Project description:Hepatocellular carcinoma (HCC) is one of the most common malignant tumors and has a poor prognosis. Ubiquitin A-52 residue ribosomal protein fusion product 1 (UBA52) encodes a fusion protein consisting of ubiquitin and ribosomal protein L40. However, few studies have explored the effects of UBA52 on HCC. In the study, we found that UBA52 is related to autophagy by the bioinformatic analysis. High‐throughput RNA‐sequencingwas used to identifydownstreamtargetgenesof EMC6. Our results suggested that UBA52 may be a new target for the prevention or treatment of HCC.
Project description:Hepatocellular carcinoma is one of the most common fatal malignancies worldwide. Thus far, the hepatocellular carcinoma prognosis has been bleak due to deficiencies in the identification and diagnosis of early hepatocellular carcinoma. Ciclopirox olamine (CPX) is a synthetic antifungal agent and has been considered as an anti-cancer candidate drug recently, though the detailed mechanisms related to its anti-cancer effect in hepatocellular carcinoma have not yet been revealed. Here, we found that CPX could inhibit proliferation in HCC cells but not in intrahepatic cholangiocarcinoma cells by arresting the cell cycle. Moreover, the anti-cancer effects of CPX in HCC cells were also attributed to CPX-triggered ROS accumulation and DJ-1 downregulation. Additionally, CPX could promote complete autophagic flux, which alleviated the anti-cancer effect of CPX in HCC cells, whereas the ROS scavenger (NAC) would attenuate CPX-induced protective autophagy. Interestingly, CPX could also induce glycogen clustering in HCC cells. Altogether, this study provides a new insight into the detailed molecular mechanisms of CPX as an anti-cancer therapy and a strategy for treating hepatocellular carcinoma.
Project description:IntroductionAutophagy is an important mechanism of cell homeostasis maintenance. As essential serine/threonine-protein kinases, casein kinase I family members affect tumorigenesis by regulating a variety of cellular progression. However, the mechanism by which they regulate autophagy remains unclear.Materials and methodsWe silenced CK1δ/ε in cancer cells and observed cell morphology, the expression of autophagy-related genes, and its impact on cancer cell growth and viability. By inhibiting CK1δ/ε-induced upregulation of autophagy genes, we profiled the regulatory mechanism of CK1δ/ε on autophagy and cancer cell growth. The impact of CK1δ/ε inhibition on tumor cell growth was also assessed in vivo.ResultsHere, we found that CK1δ/ε played an important role in ULK1-mediated autophagy regulation in both lung cancer and melanoma cells. Mechanically, silencing CK1δ/ε increased ULK1 expression with enhanced autophagic flux and suppressed cancer cell proliferation, while ULK1 knockdown blocked the activation of autophagy caused by CK1δ/ε inhibition. By silencing CK1δ/ε in syngeneic mouse model bearing LLC1 murine lung cancer cells in vivo, we observed tumor growth suppression mediated by CK1δ/ε inhibition.ConclusionOur results provide evidence for the role of CK1δ/ε in the regulation of tumorigenesis via the ULK1-mediated autophagy, and also suggest the impact of CK1δ/ε inhibition on tumor growth and its significance as a potential therapeutic target.
Project description:Phosphoinositide-specific phospholipase C (PLC) γ1 has been reported to be involved in cancer cell proliferation and metastasis. However, whether PLCγ1 modulates autophagy and the underlying mechanism remains unclear. Here, we investigated the relationship between PLCγ1 and autophagy in the human colon cancer cell line HCT116 and hepatocellular carcinoma cell line HepG2. The results indicated that PLCγ1 inhibition via lentivirus-mediated transduction with shRNA/PLCγ1 or transient transfection with pRK5-PLCγ1 (Y783A) vector increased LC3B-II levels and the number of autophagic vacuoles and decreased p62 levels. Addition of an autophagy inhibitor led to LC3B and p62 accumulation. Furthermore, AMPK activation promoted the autophagy induced by PLCγ1 inhibition by blocking the FAK/PLCγ1 axis. In addition, PLCγ1 inhibition either blocked the mTOR/ULK1 axis or enhanced dissociation of the Beclin1-IP3R-Bcl-2 complex to induce autophagy. Taken together, our findings revealed that PLCγ1 inhibition induced autophagy and the FAK/PLCγ1 axis is a potential downstream effector of the AMPK activation-dependent autophagy signalling cascade. Both blockade of the mTOR/ULK1 axis and dissociation of the Beclin1-IP3R-Bcl-2 complex contributed to the induction of autophagy by PLCγ1 inhibition. Consequently, these findings provide novel insight into autophagy regulation by PLCγ1 in colon cancer and hepatocellular carcinoma cells.
Project description:Ubiquitin-specific protease 22 (USP22) has been identified as a potential marker for cancer stem cells in hepatocellular carcinoma (HCC). It can promote HCC stemness, which is considered a driver of tumorigenesis. Here, we sought to determine the role of USP22 in tumorigenesis, elucidate its underlying mechanism, and explore its therapeutic significance in HCC. As a result, we found that tissue-specific Usp22 overexpression accelerated tumorigenesis, whereas Usp22 ablation decelerated it in a c-Myc/NRasGV12-induced HCC mouse model and that the mammalian target of rapamycin complex 1 (mTORC1) pathway was activated downstream. USP22 overexpression resulted in increased tumorigenic properties that were reversed by rapamycin in vitro and in vivo. In addition, USP22 activated mTORC1 by deubiquitinating FK506-binding protein 12 (FKBP12) and activated mTORC1, in turn, further stabilizing USP22 by inhibiting autophagic degradation. Clinically, HCC patients with high USP22 expression tend to benefit from mTOR inhibitors after liver transplantation (LT). Our results revealed that USP22 promoted tumorigenesis and progression via an FKBP12/mTORC1/autophagy positive feedback loop in HCC. Clinically, USP22 may be an effective biomarker for selecting eligible recipients with HCC for anti-mTOR-based therapy after LT.
Project description:Hepatocellular carcinoma (HCC) poses a substantial global health burden, with poor prognosis and high mortality rates. Dysregulated lipid metabolism has emerged as a critical driver of HCC progression. While mTORC1 signaling is known to promote lipid synthesis in HCC, the regulatory mechanisms governing mTORC1 remain largely unclear. Here, we demonstrate that mTORC1 inhibition significantly reduces lipogenesis in HCC and uncover a regulatory axis involving the transcription factor ATF3 and the leucine-arginine transporter SLC7A7. Transcriptomic analysis of HCC patients reveals an inverse correlation between ATF3 expression and lipid synthesis, a finding corroborated by experimental validation. Mechanistically, ATF3 suppresses mTORC1 signaling, thereby inhibiting lipid biosynthesis, with SLC7A7 identified as a key intermediary in this process. Specifically, ATF3 binds to the enhancer region of SLC7A7, driving its transcriptional activation and subsequently restraining mTORC1 activity. Functional assays in ATF3-overexpressing and -knockdown HCC cell lines further confirm ATF3's role as a tumor suppressor. Our study identifies a novel ATF3-SLC7A7-mTORC1 regulatory axis that attenuates lipogenesis and tumorigenesis in HCC, establishing a critical link between lipid metabolism and hepatocarcinogenesis. These findings offer new insights into potential therapeutic targets for the treatment of HCC.
Project description:SOCS5 is a member of the suppressor of cytokine signaling (SOCS) protein family with important yet incompletely understood biological functions in cancer. In hepatocellular carcinoma (HCC), controversial tumor-promoting and tumor-suppressive roles of SOCS5 have been reported. Our study aims to unravel novel functions of SOCS5 in HCC, especially that affecting metastasis. We examined the expression levels of SOCS5 in HCC using publicly available datasets, and in our patient cohort, using quantitative real-time PCR, western blotting, and immunohistochemistry. The association of SOCS5 expression with clinical pathological data of HCC patients was examined and that with the mTOR pathway was predicted. We further studied the effects of SOCS5 on PI3K/Akt/mTOR activity; HCC cell autophagy, migration, and invasion; and HCC cell metastasis in vitro and in vivo. We observed that SOCS5 was significantly overexpressed in HCC tissues, compared to adjacent non-tumor liver tissues, in both the public datasets and in our patient cohort. SOCS5 overexpression was significantly and inversely correlated with HCC patient prognosis. Moreover, SOCS5 overexpression promoted HCC cell migration and invasion in vitro by inactivating PI3K/Akt/mTOR-mediated autophagy. Conversely, SOCS5 inhibition suppressed HCC cell migration and invasion in vitro by activating PI3K/Akt/mTOR-mediated autophagy. Dual inhibition of SOCS5 and mTOR further enhanced autophagy and the subsequent anti-metastatic effects on HCC cells. In vivo, stable knockdown of SOCS5 reduced HCC cell metastasis. Overall, our study revealed a novel metastasis-promoting function of SOCS5 in HCC, acting via the PI3K/Akt/mTOR-mediated autophagy pathway. Combined inhibition of SOCS5 and mTOR may be a potential therapeutic approach to inhibit HCC metastasis and prolong patient survival.
Project description:Autophagy is a "self-degradative" process and is involved in the maintenance of cellular homeostasis and the control of cellular components by facilitating the clearance or turnover of long-lived or misfolded proteins, protein aggregates, and damaged organelles. Autophagy plays a dual role in cancer, including in tumor progression and tumor promotion, suggesting that autophagy acts as a double-edged sword in cancer cells. Liver cancer is one of the greatest leading causes of cancer death worldwide due to its high recurrence rate and poor prognosis. Especially in China, liver cancer has become one of the most common cancers due to the high infection rate of hepatitis virus. In primary liver cancer, hepatocellular carcinoma (HCC) is the most common type. Considering the perniciousness and complexity of HCC, it is essential to elucidate the function of autophagy in HCC. In this review, we summarize the physiological function of autophagy in cancer, analyze the role of autophagy in tumorigenesis and metastasis, discuss the therapeutic strategies targeting autophagy and the mechanisms of drug-resistance in HCC, and provide potential methods to circumvent resistance and combined anticancer strategies for HCC patients.