Research Papers: Pathology:
Chaperone-mediated autophagy compensates for impaired macroautophagy in the cirrhotic liver to promote hepatocellular carcinoma
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Srinivas Chava1, Christine Lee1, Yucel Aydin2, Partha K. Chandra1, Asha Dash1, Milad Chedid1, Swan N. Thung3, Krzysztof Moroz1, Tong Wu1, Nabeen C. Nayak4 and Srikanta Dash1
1 Department of Pathology and Laboratory Medicine, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
2 Department of Medicine, Division of Gastroenterology and Hepatology, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
3 The Lillian and Henry M. Stratton-Hans Popper Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
4 Senior Consultant and Advisor, Sir Ganga Ram Hospital, Department of Pathology, New Delhi, India
Srikanta Dash, email:
Keywords: liver cirrhosis, hepatocellular carcinoma, macroautophagy, chaperone-mediated autophagy, endoplasmic reticulum, Pathology Section
Received: January 12, 2017 Accepted: March 19, 2017 Published: March 29, 2017
Macroautophagy and chaperone-mediated autophagy (CMA) represent two major lysosomal degradation processes and often compensate for one another to facilitate cell survival. The aim of this study was to determine whether these autophagy pathways could compensate for one another to promote HCC cell survival in the cirrhotic liver. Analysis of normal liver tissue showed no expression of glypican-3 or p62 proteins, suggesting that macroautophagy is the major contributor to autophagic flux under non-pathological conditions. Of 46 cirrhotic livers with HCC examined, 39 (84%) of HCCs showed increased expression of p62, and 36 (78%) showed increased expression of glypican-3, while adjacent non-tumorous hepatocytes were negative for expression of p62 and glypican-3, similar to normal liver tissue. These results suggest that macroautophagy flux is impaired in HCC. Furthermore, more than 95% of HCCs showed altered expression of LAMP-2A compared to the surrounding non-tumorous cirrhotic liver, consistent with induction of CMA in HCC. Elevated expression of glucose-regulated protein 78 (GRP78) and heat shock cognate protein (Hsc70) were detected in 100% of HCC and adjacent non-tumorous cirrhotic livers, suggesting that unresolved ER-stress is associated with HCC risk in liver cirrhosis. Interestingly, inhibition of lysosomal degradation using hydroxychloroquine (HCQ) induced expression of the tumor suppressor p53, promoted apoptosis, and inhibited HCC growth, whereas activation of autophagy using an mTOR inhibitor (Torin1) promoted HCC growth. Results of this study suggest that induction of CMA compensates for the impairment of macroautophagy to promote HCC survival in the cirrhotic liver.
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