Oncotarget

Oncotarget Special Collections

 

Free access to organized Oncotarget publications can be used as a resource for readers in the medical science community with the curiosity to learn about a collection of studies.

 

In honor of Breast Cancer Awareness, below is the first Oncotarget Special Collection of papers directly relating to breast cancer research.

 

Special Collection on Breast Cancer

After skin cancer, breast cancer is the most common cancer diagnosed in women in the United States. Substantial support for breast cancer awareness and research funding has helped create advances in the diagnosis and treatment of breast cancer.

Breast cancer is very treatable if detected early and is treated by a Surgical oncologist which is a doctor who is trained in treating various cancers such as breast cancer, melanoma and sarcomas.

Some symptoms of Breast cancer:
  • Lump in the breast
  • Bloody discharge from the nipple
  • Peeling, scaling, crusting or flaking of the pigmented area of skin surrounding the nipple or breast skin
It is estimated that over 40,000 deaths (women and men) from breast cancer occur each year. Breast cancer is a subtype, or speciality, inside the general study of oncology and carcinogenesis, cancer cell biology, cancer diagnosis, and cancer therapy.

What is Breast Cancer?

After skin cancer, breast cancer is the most common cancer diagnosed in women in the United States. Substantial support for breast cancer awareness and research funding has helped create advances in the diagnosis and treatment of breast cancer.

Breast cancer is very treatable if detected early and is treated by a Surgical oncologist which is a doctor who is trained in treating various cancers such as breast cancer, melanoma and sarcomas.

Some symptoms of Breast cancer:
  • Lump in the breast
  • Bloody discharge from the nipple
  • Peeling, scaling, crusting or flaking of the pigmented area of skin surrounding the nipple or breast skin
It is estimated that over 40,000 deaths (women and men) from breast cancer occur each year. Breast cancer is a subtype, or speciality, inside the general study of oncology and carcinogenesis, cancer cell biology, cancer diagnosis, and cancer therapy.

Physician type:

Surgical oncologist


ANZSRC Categories:

1112 Oncology and Carcinogenesis


RCDC Category: Breast Cancer
Keywords: breast, cancer, negative, mesenchymal, triple, epithelial, transition, trastuzumab, expression, resistance, circulating, factor, derived, prognostic, metastasis

Table of Contents

Research Papers

γKlotho is a novel marker and cell survival factor in a subset of triple negative breast cancers

DOI: 10.18632/oncotarget.6006

Nuša Trošt, Samuel Peña-Llopis, Sajjan Koirala, Jurij Stojan, Patrick Ryan Potts, Klementina Fon Tacer and Elisabeth D. Martinez _

Abstract | PDF | HTML | Supplementary Files | Altmetric Report

Over the last decade, breast cancer mortality has declined. However, triple negative breast cancer (TNBC) remains a challenging problem mostly due to early recurrence and lack of molecularly driven treatments. There is a critical need to identify subgroups of TNBC with common molecular features that can be therapeutically targeted. Here we show that in contrast to Klotho and βKlotho, the third member of the Klotho protein family, γKlotho, is overexpressed in more than 60% of TNBCs and correlates with poorer disease progression. Furthermore, we find that γKlotho is expressed in a subset of TNBC cell lines promoting cell growth. Importantly, we demonstrate that in these cells γKlotho is necessary for cell survival and that its depletion leads to constitutive ERK activation, cell cycle arrest and apoptosis. Interestingly, we observe increased oxidative stress in γKlotho-depleted cells suggesting that γKlotho enables cancer cells to cope with an oxidative environment and that cells become dependent on its expression to maintain this survival advantage. These findings indicate that γKlotho might be a potential marker for patients that would benefit from treatments that alter oxidative stress and constitutes a novel drug target for a subset of TN breast cancers.

Priority Research Papers

Histone H3 lysine 4 acetylation and methylation dynamics define breast cancer subtypes

DOI: 10.18632/oncotarget.6922

Terri L. Messier, Jonathan A. R. Gordon, Joseph R. Boyd, Coralee E. Tye, Gillian Browne, Janet L. Stein, Jane B. Lian and Gary S. Stein _

Abstract | PDF | HTML | Supplementary Files | Altmetric Report

The onset and progression of breast cancer are linked to genetic and epigenetic changes that alter the normal programming of cells. Epigenetic modifications of DNA and histones contribute to chromatin structure that result in the activation or repression of gene expression. Several epigenetic pathways have been shown to be highly deregulated in cancer cells. Targeting specific histone modifications represents a viable strategy to prevent oncogenic transformation, tumor growth or metastasis. Methylation of histone H3 lysine 4 has been extensively studied and shown to mark genes for expression; however this residue can also be acetylated and the specific function of this alteration is less well known. To define the relative roles of histone H3 methylation (H3K4me3) and acetylation (H3K4ac) in breast cancer, we determined genomic regions enriched for both marks in normal-like (MCF10A), transformed (MCF7) and metastatic (MDA-MB-231) cells using a genome-wide ChIP-Seq approach. Our data revealed a genome-wide gain of H3K4ac associated with both early and late breast cancer cell phenotypes, while gain of H3K4me3 was predominantly associated with late stage cancer cells. Enrichment of H3K4ac was over-represented at promoters of genes associated with cancer-related phenotypic traits, such as estrogen response and epithelial-to-mesenchymal transition pathways. Our findings highlight an important role for H3K4ac in predicting epigenetic changes associated with early stages of transformation. In addition, our data provide a valuable resource for understanding epigenetic signatures that correlate with known breast cancer-associated oncogenic pathways.

Priority Research Papers

Camptothecin targets WRN protein: mechanism and relevance in clinical breast cancer

DOI: 10.18632/oncotarget.7906

Raghavendra A. Shamanna, Huiming Lu, Deborah L. Croteau, Arvind Arora, Devika Agarwal, Graham Ball, Mohammed A. Aleskandarany, Ian O. Ellis, Yves Pommier, Srinivasan Madhusudan and Vilhelm A. Bohr _

Abstract | PDF | HTML | Supplementary Files | Altmetric Report

Werner syndrome protein (WRN) is a RecQ helicase that participates in DNA repair, genome stability and cellular senescence. The five human RecQ helicases, RECQL1, Bloom, WRN, RECQL4 and RECQL5 play critical roles in DNA repair and cell survival after treatment with the anticancer drug camptothecin (CPT). CPT derivatives are widely used in cancer chemotherapy to inhibit topoisomerase I and generate DNA double-strand breaks during replication. Here we studied the effects of CPT on the stability and expression dynamics of human RecQ helicases. In the cells treated with CPT, we observed distinct effects on WRN compared to other human RecQ helicases. CPT altered the cellular localization of WRN and induced its degradation by a ubiquitin-mediated proteasome pathway. WRN knockdown cells as well as CPT treated cells became senescent and stained positive for senescence-associated β-galactosidase at a higher frequency compared to control cells. However, the senescent phenotype was attenuated by ectopic expression of WRN suggesting functional implication of WRN degradation in CPT treated cells. Approximately 5-23% of breast cancer tumors are known to respond to CPT-based chemotherapy. Interestingly, we found that the extent of CPT-induced WRN degradation correlates with increasing sensitivity of breast cancer cells to CPT. The abundance of WRN decreased in CPT-treated sensitive cells; however, WRN remained relatively stable in CPT-resistant breast cancer cells. In a large clinical cohort of breast cancer patients, we find that WRN and topoisomerase I expression correlate with an aggressive tumor phenotype and poor prognosis. Our novel observations suggest that WRN abundance along with CPT-induced degradation could be a promising strategy for personalizing CPT-based cancer chemotherapeutic regimens.

Reviews

Osteoprotegerin rich tumor microenvironment: implications in breast cancer

DOI: 10.18632/oncotarget.8658

Sudeshna Goswami and Neelam Sharma-Walia _

Abstract | PDF | HTML | Altmetric Report

Osteoprotegerin (OPG) is a soluble decoy receptor for tumor necrosis factor (TNF)-related apoptosis inducing ligand (TRAIL). It belongs to the tumor necrosis factor receptor superfamily (TNFRSF). OPG was initially discovered to contribute to homeostasis of bone turnover due to its capability of binding to receptor activator of nuclear factor-kappaB (NF-kB). However, apart from bone turnover, OPG plays important and diverse role(s) in many biological functions. Besides having anti-osteoclastic activity, OPG is thought to exert a protective anti-apoptotic action in OPG-expressing tumors by overcoming the physiologic mechanism of tumor surveillance exerted by TRAIL. Along with inhibiting TRAIL induced apoptosis, it can induce proliferation by binding to various cell surface receptors and thus turning on the canonical cell survival and proliferative pathways. OPG also induces angiogenesis, one of the hallmarks of cancer, thus facilitating tumor growth. Recently, the understanding of OPG and its different roles has been augmented substantially. This review is aimed at providing a very informative overview as to how OPG affects cancer progression especially breast cancer.

Priority Research Papers

Hypoxia-inducible factors regulate pluripotency factor expression by ZNF217- and ALKBH5-mediated modulation of RNA methylation in breast cancer cells

DOI: 10.18632/oncotarget.11743

Chuanzhao Zhang, Wanqing Iris Zhi, Haiquan Lu, Debangshu Samanta, Ivan Chen, Edward Gabrielson and Gregg L. Semenza _

Abstract | PDF | HTML | Altmetric Report

Exposure of breast cancer cells to hypoxia increases the percentage of breast cancer stem cells (BCSCs), which are required for tumor initiation and metastasis, and this response is dependent on the activity of hypoxia-inducible factors (HIFs). We previously reported that exposure of breast cancer cells to hypoxia induces the ALKBH5-mediated demethylation of N6-methyladenosine (m6A) in NANOG mRNA leading to increased expression of NANOG, which is a pluripotency factor that promotes BCSC specification. Here we report that exposure of breast cancer cells to hypoxia also induces ZNF217-dependent inhibition of m6A methylation of mRNAs encoding NANOG and KLF4, which is another pluripotency factor that mediates BCSC specification. Although hypoxia induced the BCSC phenotype in all breast-cancer cell lines analyzed, it did so through variable induction of pluripotency factors and ALKBH5 or ZNF217. However, in every breast cancer line, the hypoxic induction of pluripotency factor and ALKBH5 or ZNF217 expression was HIF-dependent. Immunohistochemistry revealed that expression of HIF-1α and ALKBH5 was concordant in all human breast cancer biopsies analyzed. ALKBH5 knockdown in MDA-MB-231 breast cancer cells significantly decreased metastasis from breast to lungs in immunodeficient mice. Thus, HIFs stimulate pluripotency factor expression and BCSC specification by negative regulation of RNA methylation.

Priority Research Papers

Role of TP53 mutations in triple negative and HER2-positive breast cancer treated with neoadjuvant anthracycline/taxane-based chemotherapy

DOI: 10.18632/oncotarget.11891

Silvia Darb-Esfahani _, Carsten Denkert, Albrecht Stenzinger, Christoph Salat, Bruno Sinn, Christian Schem, Volker Endris, Peter Klare, Wolfgang Schmitt, Jens-Uwe Blohmer, Wilko Weichert, Markus Möbs, Hans Tesch, Sherko Kümmel, Peter Sinn, Christian Jackisch, Manfred Dietel, Toralf Reimer, Sherene Loi, Michael Untch, Gunter von Minckwitz, Valentina Nekljudova and Sibylle Loibl

Abstract | PDF | HTML | Supplementary Files | Altmetric Report

Background: TP53 mutations are frequent in breast cancer, however their clinical relevance in terms of response to chemotherapy is controversial.

Methods: 450 pre-therapeutic, formalin-fixed, paraffin-embedded core biopsies from the phase II neoadjuvant GeparSixto trial that included HER2-positive and triple negative breast cancer (TNBC) were subjected to Sanger sequencing of exons 5-8 of the TP53 gene. TP53 status was correlated to response to neoadjuvant anthracycline/taxane-based chemotherapy with or without carboplatin and trastuzumab/lapatinib in HER2-positive and bevacizumab in TNBC. p53 protein expression was evaluated by immunohistochemistry in the TNBC subgroup.

Results: Of 450 breast cancer samples 297 (66.0%) were TP53 mutant. Mutations were significantly more frequent in TNBC (74.8%) compared to HER2-positive cancers (55.4%, P < 0.0001). Neither mutations nor different mutation types and effects were associated with pCR neither in the whole study group nor in molecular subtypes (P > 0.05 each). Missense mutations tended to be associated with a better survival compared to all other types of mutations in TNBC (P = 0.093) and in HER2-positive cancers (P = 0.071). In TNBC, missense mutations were also linked to higher numbers of tumor-infiltrating lymphocytes (TILs, P = 0.028). p53 protein overexpression was also linked with imporved survival (P = 0.019).

Conclusions: Our study confirms high TP53 mutation rates in TNBC and HER2-positive breast cancer. Mutations did not predict the response to an intense neoadjuvant chemotherapy in these two molecular breast cancer subtypes.

Priority Research Papers

Association of breast cancer risk with genetic variants showing differential allelic expression: Identification of a novel breast cancer susceptibility locus at 4q21

DOI: 10.18632/oncotarget.12818

Yosr Hamdi _, Penny Soucy, Véronique Adoue, Kyriaki Michailidou, Sander Canisius, Audrey Lemaçon, Arnaud Droit, Irene L Andrulis, Hoda Anton-Culver, Volker Arndt, Caroline Baynes, Carl Blomqvist, Natalia V. Bogdanova, Stig E. Bojesen, Manjeet K. Bolla, Bernardo Bonanni, Anne-Lise Borresen-Dale, Judith S. Brand, Hiltrud Brauch, Hermann Brenner, Annegien Broeks, Barbara Burwinkel, Jenny Chang-Claude, NBCS Collaborators, Fergus J. Couch, Angela Cox, Simon S. Cross, Kamila Czene, Hatef Darabi, Joe Dennis, Peter Devilee, Thilo Dörk, Isabel Dos-Santos-Silva, Mikael Eriksson, Peter A. Fasching, Jonine Figueroa, Henrik Flyger, Montserrat García-Closas, Graham G. Giles, Mark S. Goldberg, Anna González-Neira, Grethe Grenaker-Alnæs, Pascal Guénel, Lothar Haeberle, Christopher A. Haiman, Ute Hamann, Emily Hallberg, Maartje J. Hooning, John L. Hopper, Anna Jakubowska, Michael Jones, Maria Kabisch, Vesa Kataja, Diether Lambrechts, Loic Le Marchand, Annika Lindblom, Jan Lubinski, Arto Mannermaa, Mel Maranian, Sara Margolin, Frederik Marme, Roger L. Milne, Susan L. Neuhausen, Heli Nevanlinna, Patrick Neven, Curtis Olswold, Julian Peto, Dijana Plaseska-Karanfilska, Katri Pylkäs, Paolo Radice, Anja Rudolph, Elinor J. Sawyer, Marjanka K. Schmidt, Xiao-Ou Shu, Melissa C. Southey, Anthony Swerdlow, Rob A.E.M. Tollenaar, Ian Tomlinson, Diana Torres, , Celine Vachon, Ans M.W. Van Den Ouweland, Qin Wang, Robert Winqvist, kConFab/AOCS Investigators, Wei Zheng, Javier Benitez, Georgia Chenevix-Trench, Alison Easton, Tomi Pastinen, Silje Nord and Jacques Simard

Abstract | PDF | HTML | Supplementary Files | Altmetric Report

There are significant inter-individual differences in the levels of gene expression. Through modulation of gene expression, cis-acting variants represent an important source of phenotypic variation. Consequently, cis-regulatory SNPs associated with differential allelic expression are functional candidates for further investigation as disease-causing variants. To investigate whether common variants associated with differential allelic expression were involved in breast cancer susceptibility, a list of genes was established on the basis of their involvement in cancer related pathways and/or mechanisms. Thereafter, using data from a genome-wide map of allelic expression associated SNPs, 313 genetic variants were selected and their association with breast cancer risk was then evaluated in 46,451 breast cancer cases and 42,599 controls of European ancestry ascertained from 41 studies participating in the Breast Cancer Association Consortium. The associations were evaluated with overall breast cancer risk and with estrogen receptor negative and positive disease. One novel breast cancer susceptibility locus on 4q21 (rs11099601) was identified (OR = 1.05, P = 5.6x10-6). rs11099601 lies in a 135 kb linkage disequilibrium block containing several genes, including, HELQ, encoding the protein HEL308 a DNA dependant ATPase and DNA Helicase involved in DNA repair, MRPS18C encoding the Mitochondrial Ribosomal Protein S18C and FAM175A (ABRAXAS), encoding a BRCA1 BRCT domain-interacting protein involved in DNA damage response and double-strand break (DSB) repair. Expression QTL analysis in breast cancer tissue showed rs11099601 to be associated with HELQ (P = 8.28x10-14), MRPS18C (P = 1.94x10-27) and FAM175A (P = 3.83x10-3), explaining about 20%, 14% and 1%, respectively of the variance inexpression of these genes in breast carcinomas.

Priority Research Papers

LINC00520 is induced by Src, STAT3, and PI3K and plays a functional role in breast cancer

DOI: 10.18632/oncotarget.11962

Whitney S. Henry, David G. Hendrickson, Francisco Beca, Benjamin Glass, Marianne Lindahl-Allen, Lizhi He, Zhe Ji, Kevin Struhl, Andrew H. Beck, John L. Rinn and Alex Toker _

Abstract | PDF | HTML | Supplementary Files | Altmetric Report

Long non-coding RNAs (lncRNAs) have been implicated in normal cellular homeostasis as well as pathophysiological conditions, including cancer. Here we performed global gene expression profiling of mammary epithelial cells transformed by oncogenic v-Src, and identified a large subset of uncharacterized lncRNAs potentially involved in breast cancer development. Specifically, our analysis revealed a novel lncRNA, LINC00520 that is upregulated upon ectopic expression of oncogenic v-Src, in a manner that is dependent on the transcription factor STAT3. Similarly, LINC00520 is also increased in mammary epithelial cells transformed by oncogenic PI3K and its expression is decreased upon knockdown of mutant PIK3CA. Additional expression profiling highlight that LINC00520 is elevated in a subset of human breast carcinomas, with preferential enrichment in the basal-like molecular subtype. ShRNA-mediated depletion of LINC00520 results in decreased cell migration and loss of invasive structures in 3D. RNA sequencing analysis uncovers several genes that are differentially expressed upon ectopic expression of LINC00520, a significant subset of which are also induced in v-Src-transformed MCF10A cells. Together, these findings characterize LINC00520 as a lncRNA that is regulated by oncogenic Src, PIK3CA and STAT3, and which may contribute to the molecular etiology of breast cancer.

Research Papers

SNPs in the interleukin-12 signaling pathway are associated with breast cancer risk in Puerto Rican women

DOI: 10.18632/oncotarget.27707

Angel Núñez-Marrero, Nelly Arroyo, Lenin Godoy, Mohammad Zillur Rahman, Jaime L. Matta and Julie Dutil _

Abstract | PDF | HTML | Supplementary Files | Altmetric Report

Interleukin-12 (IL-12) is a proinflammatory cytokine that links innate and adaptive immune responses against tumor cells. Single Nucleotide Polymorphisms (SNPs) in IL-12 genes have been associated with cancer risk. However, limited studies have assessed the role of IL-12 in breast cancer (BC) risk comprehensively, and these were done in European and Asian populations. Here, we evaluated the association of the IL-12 signaling pathway and BC risk in Puerto Rican women. A genetic association study was completed with 461 BC cases and 463 non-BC controls. By logistic regression, IL-12 signaling SNPs were associated with an increased BC risk, including rs2243123 (IL12A), rs3761041, rs401502 and rs404733 (IL12RB1), rs7849191 (JAK2), rs280500 (TYK2) and rs4274624 (STAT4). Conversely, other SNPs were associated with reduced BC risk including rs438421 (IL12RB1), rs6693065 (IL12RB2), rs10974947, and rs2274471 (JAK2), rs10168266 and rs925847 (STAT4), and rs2069718 (IFNG). Analyses based in hormone receptors such as estrogen (ER) and progesterone (PR) receptors also revealed protective (for SNPs rs3212227-IL12B; rs3024896 and rs3821236-STAT4) and predisposing (for rs2069705-IFNG SNP) BC associations. Haplotype analysis showed a decreased BC risk for IL12B and STAT4 SNPs, whereas increased risk for IL12RB1 SNPs. This study suggests a role of the IL-12 signaling axis and BC risk. SNPs in this pathway may alter IL-12 induced anti-tumor responses and modulate BC predisposition in a population-specific context. Functional studies will be necessary to confirm these findings, which potentially may benefit IL-12 related immunotherapeutic approaches towards BC.

Research Papers

Sequencing for an interdisciplinary molecular tumor board in patients with advanced breast cancer: experiences from a case series

DOI: 10.18632/oncotarget.27704

Christina Walter, Andreas Hartkopf _, Andre Koch, Marion Klaumünzer, Martin Schulze, Eva-Maria Grischke, Florin-Andrei Taran, Sara Brucker, Florian Battke and Saskia Biskup

Abstract | PDF | HTML | Supplementary Files | Altmetric Report | Press Release

Purpose: High throughput panel sequencing to tailor therapy in precision oncology promises to improve outcome in patients with metastatic breast cancer. However, data that clearly show any benefit from such an approach is still pending.

Materials and Methods: We performed a retrospective analysis of advanced breast cancer patients that underwent panel sequencing for suggestion of target related drugs. We aimed to (i) determine the frequency of actionable mutations per patient and to (ii) assess the clinical impact of results on treatment options.

Results: A total of 52 patients underwent panel sequencing of archived tumor tissue. Every sample showed at least one affected gene, accounting for actionable mutations in 45 of 52 patients (87%). New treatment options that would not have been used as indicated by standard predictive markers (such as hormonal receptor status or HER2-status) were found in 22 of 52 patients (42%). We detected therapeutic relevant pathogenic germline variants in 9,6% (5/52) of the patients.

Conclusions: Using a high throughput-panel sequencing approach to identify actionable mutations in patients with metastatic breast cancer, we identified potential target-related treatment options in a large proportion of our patients, some of which would not have been considered without this data. Prospective clinical trials with compounds targeting the identified actionable mutations are needed to determine which treatments can indeed improve survival or quality of life by limiting exposure to ineffective drugs in advanced breast cancer.

Research Papers

Induction of phenotypic changes in HER2-postive breast cancer cells in vivo and in vitro

DOI: 10.18632/oncotarget.27679

Anastasia Frank-Kamenetskii, Julia Mook, Meredith Reeves, Corinne A. Boulanger, Thomas J. Meyer, Lauren Ragle, H. Caroline Jordan, Gilbert H. Smith and Brian W. Booth _

Abstract | PDF | HTML | Altmetric Report | Press Release

The influence of breast cancer cells on normal cells of the microenvironment, such as fibroblasts and macrophages, has been heavily studied but the influence of normal epithelial cells on breast cancer cells has not. Here using in vivo and in vitro models we demonstrate the impact epithelial cells and the mammary microenvironment can exert on breast cancer cells. Under specific conditions, signals that originate in epithelial cells can induce phenotypic and genotypic changes in cancer cells. We have termed this phenomenon “cancer cell redirection.” Once breast cancer cells are redirected, either in vivo or in vitro, they lose their tumor forming capacity and undergo a genetic expression profile shift away from one that supports a cancer profile towards one that supports a non-tumorigenic epithelial profile. These findings indicate that epithelial cells and the normal microenvironment influence breast cancer cells and that under certain circumstances restrict proliferation of tumorigenic cells.

Research Papers

Th1 cytokines in conjunction with pharmacological Akt inhibition potentiate apoptosis of breast cancer cells in vitro and suppress tumor growth in vivo

DOI: 10.18632/oncotarget.27556

Loral Showalter, Brian J. Czerniecki and Gary K. Koski _

Abstract | PDF | HTML | Supplementary Files | Altmetric Report | Press Release

Targeted drug approaches have been a major focus for developing new anticancer therapies. Although many such agents approved in the last 20 years have improved outcomes, almost all have underperformed expectations. The full potential of such agents may yet be obtained through novel combinations. Previously, we showed that anti-estrogen drugs combined with a dendritic cell-based anti-HER-2 vaccine known to induce strong Th1-polarized immunity dramatically improved clinical response rates in patients with HER-2pos/ERpos early breast cancer. Here, we show that the small molecule Akt antagonist MK-2206, when combined with the Th1 cytokines IFN-gamma and TNF-alpha, maximize indicators of apoptotic cell death in a panel of phenotypically-diverse human breast cancer lines. These findings were mirrored by other, structurally-unrelated Akt-targeting drugs that work through different mechanisms. Interestingly, we found that MK-2206, as well as the other Akt antagonist drugs, also had a tendency to suppress Th1 cytokine expression in stimulated human and murine lymphocytes, potentially complicating their use in conjunction with active immunotherapy. After verifying that MK-2206 plus IFN-gamma could show similar combined effects against breast cancer lines, even in the absence of TNF-alpha, we tested in a rodent HER-2pos breast cancer model either a HER-2-based DC vaccine, or recombinant IFN-gamma with or without MK-2206 administration. We found that for MK-2206, co-administration of recombinant IFN-gamma outperformed co-administration of DC vaccination for slowing tumor growth kinetics. These findings suggest a combined therapy approach for Akt-targeting drugs that incorporates recombinant Interferon-gamma and is potentially translatable to humans.

Research Papers

Inhibition of HAS2 and hyaluronic acid production by 1,25-Dihydroxyvitamin D3 in breast cancer

DOI: 10.18632/oncotarget.27587

Carmen J. Narvaez, Erika LaPorta, Samantha Robilotto, Jennifer Liang and JoEllen Welsh _

Abstract | PDF | HTML | Supplementary Files | Altmetric Report | Press Release

1,25-Dihydroxyvitamin D3 (1,25D3) induces growth arrest and apoptosis in breast cancer cells in vivo and in vitro, however the exact mechanisms are unclear. Although the vitamin D receptor (VDR), a ligand dependent transcription factor, is required for growth regulation by vitamin D, the specific target genes that trigger these effects are unknown. Genomic profiling of murine mammary tumor cells with differential VDR expression identified 35 transcripts that were altered by the 1,25D3-VDR complex including Hyaluronan Synthase-2 (Has2). Here we confirmed that 1,25D3 reduces both HAS2 gene expression and hyaluronic acid (HA) synthesis in multiple models of breast cancer. Furthermore, we show that the growth inhibitory effects of 1,25D3 are partially reversed in the presence of high molecular weight HA. HAS2 expression and HA production are elevated in immortalized human mammary epithelial cells induced to undergo epithelial-mesenchymal transition (EMT) through stable expression of TGFβ, SNAIL or TWIST and in those expressing oncogenic H-RASV12, indicating that deregulation of HA production may be an early and frequent event in breast tumorigenesis. 1,25D3 also reduces HA secretion and acts additively with an HA synthesis inhibitor to slow growth of cells expressing TGFβ, SNAIL and TWIST. Analysis of mammary gland and tumors from Vdr knockout mice suggest that loss of VDR is associated with enhanced HAS2 expression and HA production in vivo. These data define a novel role for 1,25D3 and the VDR in control of HA synthesis in epithelial tissues that likely contributes to its anti-cancer actions.

Research Papers

Baicalin inhibits the TGF-β1/p-Smad3 pathway to suppress epithelial-mesenchymal transition-induced metastasis in breast cancer

DOI: 10.18632/oncotarget.27677

Ding-Kuo Liu, Hui-Feng Dong, Rui-Fen Liu and Xi-Long Xiao _

Abstract | PDF | HTML | Altmetric Report

TGF-β1 is an epithelial-mesenchymal transition (EMT)-inducing factor that is critical in tumor progression. However, whether the effect of TGF-β1 on breast cancer is through the EMT pathway remains to be determined, and drug development based on this mechanism needs to be improved. Results of this study showed that TGF-β1 dysregulation significantly correlated with the expression levels of EMT-associated markers and transcriptional factors. Exogenous expression of TGF-β1 promoted breast cancer cell metastasis and EMT progression. In addition, direct binding of baicalin to TGF-β1 caused its inactivation, which subsequently blocked signal transduction and inhibited breast cancer cell metastasis. In vivo experiment results further invalidated the inhibitory effect of baicalin on TGF-β1-induced tumor metastasis. These results suggest that baicalin, an active ingredient used in traditional Chinese medicine, exhibits a potential therapeutic effect on breast cancer metastasis by regulating TGF-β1-dependent EMT progression.

Research Papers

Novel role for the Golgi membrane protein TMEM165 in control of migration and invasion for breast carcinoma

DOI: 10.18632/oncotarget.27668

Pavitra Murali, Blake P. Johnson, Zhongpeng Lu, Leslie Climer, Danielle A. Scott, Francois Foulquier, Gabriela Oprea-Ilies, Vladimir Lupashin, Richard R. Drake and Karen L. Abbott _

Abstract | PDF | HTML | Supplementary Files | Altmetric Report | Press Release

The TMEM165 gene encodes for a multiple pass membrane protein localized in the Golgi that has been linked to congenital disorders of glycosylation. The TMEM165 protein is a putative ion transporter that regulates H+/Ca++/Mn++ homeostasis and pH in the Golgi. Previously, we identified TMEM165 as a potential biomarker for breast carcinoma in a glycoproteomic study using late stage invasive ductal carcinoma tissues with patient- matched adjacent normal tissues. The TMEM165 protein was not detected in non-malignant matched breast tissues and was detected in invasive ductal breast carcinoma tissues by mass spectrometry. Our hypothesis is that the TMEM165 protein confers a growth advantage to breast cancer. In this preliminary study we have investigated the expression of TMEM165 in earlier stage invasive ductal carcinoma and ductal carcinoma in situ cases. We created a CRISPR/Cas9 knockout of TMEM165 in the human invasive breast cancer cell line MDAMB231. Our results indicate that removal of TMEM165 in these cells results in a significant reduction of cell migration, tumor growth, and tumor vascularization in vivo. Furthermore, we find that TMEM165 expression alters the glycosylation of breast cancer cells and these changes promote the invasion and growth of breast cancer by altering the expression levels of key glycoproteins involved in regulation of the epithelial to mesenchymal transition such as E-cadherin. These studies illustrate new potential functions for this Golgi membrane protein in the control of breast cancer growth and invasion.

Research Papers

Working together for the family: determination of HER oncogene co-amplifications in breast cancer

DOI: 10.18632/oncotarget.27671

Sergio Laurito, María Teresita Branham, Emanuel Campoy, Sebastián Real, Juan Cueto, Guillermo Urrutia, Francisco Gago, Olga Tello, Telma Glatstein, Paola De la Iglesia, Lilit Atanesyan, Suvi Savola and Maria Roqué _

Abstract | PDF | HTML | Supplementary Files | Altmetric Report | Press Release

HER2 is a well-studied tyrosine kinase (TK) membrane receptor which functions as a therapeutic target in invasive ductal breast carcinomas (IDC). The standard of care for the treatment of HER2-positive breast is the antibody trastuzumab. Despite specific treatment unfortunately, 20% of primary and 70% of metastatic HER2 tumors develop resistance. HER2 belongs to a gene family, with four members (HER1-4) and these members could be involved in resistance to anti-HER2 therapies. In this study we designed a probemix to detect the amplification of the four HER oncogenes in a single reaction. In addition, we developed a protocol based on the combination of MLPA with ddPCR to detect the tumor proportion of co-amplified HERs. On 111 IDC, the HER2 MLPA results were validated by FISH (Adjusted r2 = 0,91, p < 0,0001), CISH (Adjusted r2 = 0,938, p < 0,0001) and IHC (Adjusted r2 = 0,31, p < 0,0001). HER1-4 MLPA results were validated by RT-qPCR assays (Spearman Rank test p < 0,05). Of the 111 samples, 26% presented at least one HER amplified, of which 23% showed co-amplifications with other HERs. The percentage of cells with HER2 co-amplified varied among the tumors (from 2–72,6%). Independent in-silico findings show that the outcome of HER2+ patients is conditioned by the status of HER3 and HER4. Our results encourage further studies to investigate the relationship with patient’s response to single or combined treatment. The approach could serve as proof of principle for other tumors in which the HER oncogenes are involved.

Research Papers

Amplifications of stemness genes and the capacity of breast tumors for metastasis

DOI: 10.18632/oncotarget.27608

Nikolai Litviakov _, Marina Ibragimova, Matvey Tsyganov, Polina Kazantseva, Irina Deryusheva, Alina Pevzner, Artem Doroshenko, Eugeny Garbukov, Natalia Tarabanovskaya and Elena Slonimskaya

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Introduction: The phenomenon of non-CSC (cancer stem cell) to CSC plasticity has been previously described in multiple studies and occurs during the ectopic expression of stemness genes such as OCT3, SOX2, KLF4, MYC, NOTCH1, and NANOG. In our opinion, acquiring the ability to ectopically express stemness genes, selected by bioinformatics analysis and, accordingly, non-CSC to CSC plasticity, is due to amplification of genes at the following locations: 3q, 5p, 6p, 7q, 8q, 13q, 9p, 9q, 10p, 10q21.1, 16p, 18chr, 19p. This paper demonstrates the significance of stemness gene amplifications leading to metastasis and stem-like cancer cell activity.

Materials and Methods: In our studies, stemness gene amplifications were determined using the CytoScan HD Array. We studied the association of changes in stemness gene amplifications in tumors with metastasis treated with neoadjuvant chemotherapy (NAC) in 50 patients with breast cancer. We used qPCR to evaluate the expression of 13 stemness genes in tumors before and after NAC in 98 patients with breast cancer. Using primary cultures from the breast tumor of patient St23784/17 with stemness gene amplifications (SOX2, MYC, KLF4, NOTCH1, NODAL) and patient Ti41749/17 without stemness gene amplifications in the tumor, we studied the expression of stemness genes, proliferative tumor stem-cell activity, mammosphere formation, and expression of the CD44 tumor stem cell marker.

Results: The occurrence of amplifications at regions of stemness gene localization during NAC (22% cases) in residual tumors was associated with a very high metastasis rate (91% cases). Eliminating tumor clones with stemness gene amplifications using NAC (42% cases) led to 100% metastasis-free survival.

In patients who developed hematogenic metastases after treatment, the expression of 7/13 stemness genes in the residual tumor after NAC was statistically higher than in patients without metastases. Primary cultures of EpCam+ tumor cells from patients with stemness gene amplifications revealed high proliferative activity. After the 3rd passage, the number of tumor cells increased 30-fold. Due to IL-6, this cell population showed a 2.5-fold increase in the EpCam+CD44hiCD24–/low and 2-fold decrease in the EpCam+CD44lowCD24 subpopulations of tumor stem cells; the formation of mammospheres was also observed. Primary cultures of EpCam+ tumor cells from the patient with no stemness gene amplifications had relatively low proliferative activity. IL-6 caused a 2.3-fold increase in the EpCam+CD44lowCD24 and 2-fold decrease in the EpCam+CD44hiCD24–/low subpopulations of tumor stem cells with no induction of mammospheres.

Conclusions: The results of this study show that stemness gene amplifications in tumor cells are associated with metastasis and determine their potential stem property activation and non-CSC to CSC plasticity with the formation of EpCam+CD44hiCD24–/low cells, active proliferation, mammosphere formation, and metastasis.

Research Papers

Expression of receptor activator of NFkB (RANK) drives stemness and resistance to therapy in ER+HER2- breast cancer

DOI: 10.18632/oncotarget.27576

Inês Gomes, Bernardo P. de Almeida, Sara Dâmaso, André Mansinho, Inês Correia, Sara Henriques, Raquel Cruz-Duarte, Guilherme Vilhais, Pedro Félix, Patrícia Alves, Patrícia Corredeira, Nuno L. Barbosa-Morais, Luis Costa and Sandra Casimiro _

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The role of RANKL-RANK pathway in progesterone-driven mammary carcinogenesis and triple negative breast cancer tumorigenesis has been well characterized. However, and despite evidences of the existence of RANK-positive hormone receptor (HR)-positive breast tumors, the implication of RANK expression in HR-positive breast cancers has not been addressed before. Here, we report that RANK pathway affects the expression of cell cycle regulators and decreases sensitivity to fulvestrant of estrogen receptor (ER)-positive (ER+)/HER2- breast cancer cells, MCF-7 and T47D. Moreover, RANK overexpressing cells had a staminal and mesenchymal phenotype, with decreased proliferation rate and decreased susceptibility to chemotherapy, but were more invasive in vivo. In silico analysis of the transcriptome of human breast tumors, confirmed the association between RANK expression and stem cell and mesenchymal markers in ER+HER2- tumors. Importantly, exposure of ER+HER2- cells to continuous RANK pathway activation by exogenous RANKL, in vitro and in vivo, induced a negative feedback effect, independent of RANK levels, leading to the downregulation of HR and increased resistance to hormone therapy. These results suggest that ER+HER2- RANK-positive cells may constitute an important reservoir of slow cycling, therapy-resistance cancer cells; and that RANK pathway activation is deleterious in all ER+HER2- breast cancer cells, independently of RANK levels.

Research Papers

Distinct pattern of one-carbon metabolism, a nutrient-sensitive pathway, in invasive breast cancer: A metabolomic study

DOI: 10.18632/oncotarget.27575

Jéssica Reis Santos _, Dan Linetzky Waitzberg, Ismael Dale Cotrim Guerreiro da Silva, Tharcisio Citrangulo Tortelli Junior, Luciana Rodrigues Carvalho Barros, Gisele André Baptista Canuto, Andréa Tedesco Faccio, Lydia Fumiko Yamaguchi, Massuo Jorge Kato, Marina Franco Maggi Tavares, Ana Cristina Martinez, Ângela Flavia Logullo, Raquel Suzana M.M. Torrinhas and Graziela Ravacci

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Altered cell metabolism is a hallmark of cancer and critical for its development. Particularly, activation of one-carbon metabolism in tumor cells can sustain oncogenesis while contributing to epigenetic changes and metabolic adaptation during tumor progression. We assessed whether increased one-carbon metabolism activity is a metabolic feature of invasive ductal carcinoma (IDC). Differences in the metabolic profile between biopsies from IDC (n = 47) and its adjacent tissue (n = 43) and between biopsies from different breast cancer subtypes were assessed by gas spectrometry in targeted (Biocrates Life Science®) and untargeted approaches, respectively. The metabolomics data were statistically treated using MetaboAnalyst 4.0, SIMCA P+ (version 12.01), Statistica 10 software and t test with p < 0.05. The Cancer Genome Atlas breast cancer dataset was also assessed to validate the metabolomic profile of IDC. Our targeted metabolomics analysis showed distinct metabolomics profiles between IDC and adjacent tissue, where IDC displayed a comparative enrichment of metabolites involved in one-carbon metabolism (serine, glycine, threonine, and methionine) and a predicted increase in the activity of pathways that receive and donate carbon units (i.e., folate, methionine, and homocysteine). In addition, the targeted and untargeted metabolomics analyses showed similar metabolomics profiles between breast cancer subtypes. The gene set enrichment analysis identified different transcription-related functions between IDC and non-tumor tissues that involved one-carbon metabolism. Our data suggest that one-carbon metabolism may be a central pathway in IDC and even in general breast tumors, representing a potential target for its treatment and prevention.

Research Papers

Proteomic analysis of combined IGF1 receptor targeted therapy and chemotherapy identifies signatures associated with survival in breast cancer patients

DOI: 10.18632/oncotarget.27566

Tali Sinai-Livne, Metsada Pasmanik-Chor, Zoya Cohen, Ilan Tsarfaty, Haim Werner _ and Raanan Berger

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Clinical, epidemiological and experimental data identified the insulin-like growth factor-1 receptor (IGF1R) as a candidate therapeutic target in oncology. While this paradigm is based on well-established biological facts, including the potent anti-apoptotic and cell survival capabilities of the receptor, most Phase III clinical trials designed to target the IGF1R led to disappointing results. The present study was aimed at evaluating the hypothesis that combined treatment composed of selective IGF1R inhibitor along with classical chemotherapy might be more effective than individual monotherapies in breast cancer treatment. Analyses included comprehensive measurements of the synergism achieved by various combination regimens using the CompuSyn software. In addition, proteomic analyses were conducted to identify the proteins involved in the synergistic killing effect at a global level. Data presented here demonstrates that co-treatment of IGF1R inhibitor along with chemotherapeutic drugs markedly improves the therapeutic efficiency in breast cancer cells. Of clinical relevance, our analyses indicate that high IGF1R baseline expression may serve as a predictive biomarker for IGF1R targeted therapy. In addition, we identified a ten-genes signature with potential predictive value. In conclusion, the use of a series of bioinformatics tools shed light on some of the biological pathways that might be responsible for synergysm in cancer therapy.

Reviews

Risk factors for breast cancer brain metastases: a systematic review

DOI: 10.18632/oncotarget.27453

Lola Koniali, Andreas Hadjisavvas, Anastasia Constantinidou, Kyproula Christodoulou, Yiolanda Christou, Christiana Demetriou, Andreas S. Panayides, Constantinos Pitris, Constantinos S. Pattichis, Eleni Zamba-Papanicolaou and Kyriacos Kyriacou _

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Background: Brain metastasis (BM) is an increasingly common and devastating complication of breast cancer (BC).

Methods: A systematic literature search of EMBASE and MEDLINE was conducted to elucidate the current state of knowledge on known and novel prognostic factors associated with 1) the risk for BCBM and 2) the time to brain metastases (TTBM).

Results: A total of 96 studies involving institutional records from 28 countries were identified. Of these, 69 studies reported risk factors of BCBM, 46 factors associated with the TTBM and twenty studies examined variables for both outcomes. Young age, estrogen receptor negativity (ER-), overexpression of human epidermal factor (HER2+), and higher presenting stage, histological grade, tumor size, Ki67 labeling index and nodal involvement were consistently found to be independent risk factors of BCBM. Of these, triple-negative BC (TNBC) subtype, ER-, higher presenting histological grade, tumor size, and nodal involvement were also reported to associate with shorter TTBM. In contrast, young age, hormone receptor negative (HR-) status, higher presenting stage, nodal involvement and development of liver metastasis were the most important risk factors for BM in HER2-positive patients.

Conclusions: The study provides a comprehensive and individual evaluation of the risk factors that could support the design of screening tools and interventional trials for early detection of BCBM.

Research Papers

Exercise reduces immune suppression and breast cancer progression in a preclinical model

DOI: 10.18632/oncotarget.27464

Erik Wennerberg, Claire Lhuillier, Marissa D. Rybstein, Kyle Dannenberg, Nils-Petter Rudqvist, Graeme J. Koelwyn, Lee W. Jones and Sandra Demaria _

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Exercise is associated with favorable changes in circulating immune cells and improved survival in early-stage breast cancer patients, but the mechansims remain to be fully elucidated. Preclinical studies indicate that physical activity started before tumor injection reduces tumor incidence and progression. Here we tested whether exercise has anti-tumor effects in mice with established 4T1 mammary carcinoma, a mouse model of triple negative breast cancer. Exercise slowed tumor progression and reduced the tumor-induced accumulation of myeloid-derived suppressor cells (MDSCs). The reduction in MDSCs was accompanied by a relative increase in natural killer and CD8 T cell activation, suggesting that exercise restores a favorable immune environment. Consistently, exercise improved responses to a combination of programmed cell death protein 1 (PD-1) blockade and focal radiotherapy. These data support further investigations of exercise in breast cancer patients treated with combinations of immunotherapy and cytotoxic agents to improve cancer outcomes.

Research Papers

Therapeutic inhibition of Mcl-1 blocks cell survival in estrogen receptor-positive breast cancers

DOI: 10.18632/oncotarget.27070

Michelle M. Williams, David L. Elion, Bushra Rahman, Donna J. Hicks, Violeta Sanchez and Rebecca S. Cook

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Cancers often overexpress anti-apoptotic Bcl-2 proteins for cell death evasion, a recognized hallmark of cancer progression. While estrogen receptor (ER)-α+ breast cancers express high levels of three anti-apoptotic Bcl-2 family members (Bcl-2, Bcl-xL, and Mcl-1), pharmacological inhibition of Bcl-2 and/or Bcl-xL fails to induce cell death in ERα+ breast cancer cell lines, due to rapid and robust Mcl-1 upregulation. The mechanisms of acute Mcl-1 upregulation in response to Bcl-2/Bcl-xL inhibition remain undefined in in ERα+ breast cancers. We report here that blockade of Bcl-2 or Bcl-xL, alone or together, rapidly induced mTOR signaling in ERα+ breast cancer cells, rapidly increasing cap-dependent Mcl-1 translation. Cells treated with a pharmacological inhibitor of cap-dependent translation, or with the mTORC1 inhibitor RAD001/everolimus, displayed reduced protein levels of Mcl-1 under basal conditions, and failed to upregulate Mcl-1 protein expression following treatment with ABT-263, a pharmacological inhibitor of Bcl-2 and Bcl-xL. Although treatment with ABT-263 alone did not sustain apoptosis in tumor cells in culture or in vivo, ABT-263 plus RAD001 increased apoptosis to a greater extent than either agent used alone. Similarly, combined use of the selective Mcl-1 inhibitor VU661013 with ABT-263 resulted in tumor cell apoptosis and diminished tumor growth in vivo. These findings suggest that rapid Mcl-1 translation drives ABT-263 resistance, but can be combated directly using emerging Mcl-1 inhibitors, or indirectly through existing and approved mTOR inhibitors.



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