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Liver cancer, which is the second leading cause of tumor-associated mortality, is of great concern worldwide due to its resistance to chemotherapeutic drugs. Transcatheter arterial chemoembolization (TACE) has previously been used as a treatment for unresectable liver tumors in China; however, the response to TACE treatment differs between patients. It has been reported that hepatitis B virus (HBV)-as sociated tumors are less sensitive to TACE treatment compared with non-HBV-associated liver cancer. Previous studies have demonstrated that exosomes serve a crucial role in hepatic carcinoma chemoresistance. We therefore hypothesized that HBV may modulate chemosensitivity via exosomes. The aim of the present study was to investigate how exosomes affect chemoresistance by assessing their role in chaperone-mediated autophagy (CMA)-dependent chemoresistance in HBV-associated liver cancer. Iconography data from HBV-positive and HBV-negative patients with hepatic carcinoma receiving TACE treatment were assessed, and it was revealed that the tumor volume was decreased in the patients with non-HBV-associated liver cancer compared with that in the patients with HBV-associated tumors following TACE therapy. Furthermore, it was revealed that exosomes from HBV-infected liver cancer cells were able to downregulate cell apoptosis when treated with oxaliplatin compared with exosomes from normal HepG2 cells. Furthermore, the results demonstrated that HBV-associated exosomes modulate cell death via activating the CMA pathway, and its key molecule, lysosome-associated membrane protein (Lamp2a), was also upregulated. Lamp2a-knockdown was also found to reverse anti-apoptotic effects in liver cancer. Taken together, the results of the present study suggest that chemoresistance in patients with HBV-associated hepatic tumors may be mediated by exosomes, and thus may provide a basis for the development of novel treatment strategies for chemoresistant liver cancer.

Abstract. The interleukin (IL)-17/IL-17 receptor (IL-17R)complex has been shown to be important for the regulation of inflammation; however, its role in the regulation of tumor processes has recently emerged as a research focus. The present study demonstrated that oxaliplatin was able to increase the levels of IL-17/IL-17R in hepatocellular carcinoma (HCC) patients and cells lines, and that it had important roles in reducing the susceptibility of the cells to oxaliplatin-induced apoptosis. Furthermore, the expression of autophagy-related proteins was induced by IL-17/IL-17R and autophagy was shown to induce resistance to oxaliplatin in HCC. In addition, the janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway was shown to be an important pathway in the induction of autophagy in response to oxaliplatin. Autopjhagy was inhibited by 3-methyladenine and JAK2/STAT3 signaling was blocked by AG490, which induced apoptosis in SMMC7721 cells treated with oxaliplatin. The results of the present study may help to elucidate the mechanism underlying the role of IL-17/IL-17R-induced autophagy in the chemoresistance of HCC, as well as help to establish and develop measures to overcome chemoresistance in HCC. IntroductionHepatocellular carcinoma (HCC) is a major malignancy worldwide and its incidence is increasing annually; it is the second most common cause of cancer-associated mortality (1).The majority of patients have a low survival rate as a result of locally advanced or metastatic diseases, and surgery is feasible for only a small percentage of patients with HCC. Therefore, chemotherapy is the optimal therapeutic strategy for inoperable HCC (2). Oxaliplatin has been widely used in chemotherapy to reduce tumor recurrence and prolong survival in patients with HCC because of its fewer side effects compared with other platinum drugs (3). However, chemoresistance to oxaliplatin in the form of suppressed HCC apoptosis is commonly observed (4).Interleukin-17 (IL-17) is predominantly secreted by interleukin-17-producing T-helper (Th17) cells, which participate in the progression and pathogenesis of inflammatory diseases (3). The IL-17 receptor (IL-17R) is expressed on the surface of numerous cells, including macrophages, dendritic cells, epithelial cells, fibroblasts and T lymphocytes (5,6). Previous studies reported that IL-17-producing cells accumulated in tumors (7,8), and that patients with malignant serum effusions (9) or multiple myeloma (10) showed significantly higher serum levels of IL-17. Furthermore, patients with persistently higher levels of IL-17 demonstrated the requirement for longer courses of chemotherapy, since these patients comprised a significant proportion of all cases of recurrence (11). Typically, IL-17 does not engage with Toll/IL-1 receptor (TIR) domain-containing adaptors, such as MyD88, TIR domain-containing adapter protein inducing interferon-β or IL-1 receptor-associated kinases (12). Rather, IL-17 signals through nuclear factor (NF)-κB (13), mitogen-activated pro...