ENKUR expression induced by chemically synthesized cinobufotalin suppresses malignant activities of hepatocellular carcinoma by modulating β-catenin/c-Jun/MYH9/USP7/c-Myc axis

Abstract

ENKUR plays a crucial role in lung and colorectal cancers. Chemically synthesized cinobufotalin (CB) showed its significant anti-cancer effect in nasopharyngeal carcinoma. However, the roles of ENKUR and CB along with their correlation are still unknown in hepatocellular carcinoma (HCC). In this study, ENKUR expression in HCC tissue and cells were detected. The relationship between ENKUR expression and clinical pathology was also assessed. In vivo and in vitro experiments were conducted to explore the effects and molecular basis of ENKUR and CB in HCC. ENKUR expression was correlated with HCC progression and patient prognosis. Furthermore, ENKUR could inhibit tumor proliferation, metastasis, and sorafenib resistance in HCC. Mechanistic studies showed that ENKUR or its Enkurin domain could bind to MYH9 and decrease its expression by binding to β-catenin and inhibiting its nuclear transfer, thus decreasing c-Jun level. Low expression of MYH9 suppressed recruitment of deubiquitination enzyme USP7, promoting degradation of the c-Myc. Therefore, cell cycle and EMT signals were suppressed. CB as a safe and effective anti-cancer compound up-regulates the expression of ENKUR via inhibiting PI3K/AKT/c-Jun-mediated transcription suppression. These findings show that ENKUR induced by CB antagonizes β-catenin/c-Jun/MYH9/USP7 pathway, thus increasing c-Myc ubiquitin degradation and finally suppressing cell cycle and EMT signals.

ENKUR recruits FBXW7 to ubiquitinate and degrade MYH9 and further suppress MYH9‐induced deubiquitination of β‐catenin to block gastric cancer metastasis

“…Although MYH9 was originally identified as a tumor suppressive factor in squamous cell carcinoma of head and neck, 17 recent studies support a role for MYH9 as an oncoprotein in many tumors, including GC 18–23 . Interestingly, in previous studies, we have demonstrated that MYH9 interacted with ENKUR and antagonized ENKUR to induce‐cell growth and metastasis in hepatocellular carcinoma, lung adenocarcinoma, and nasopharyngeal carcinoma via suppressing p53 or elevating c‐Myc 13–15 . Nevertheless, there is no document to clarify the mechanism of ENKUR to modulate MYH9 in GC.…”

“… 18 , 19 , 20 , 21 , 22 , 23 Interestingly, in previous studies, we have demonstrated that MYH9 interacted with ENKUR and antagonized ENKUR to induce‐cell growth and metastasis in hepatocellular carcinoma, lung adenocarcinoma, and nasopharyngeal carcinoma via suppressing p53 or elevating c‐Myc. 13 , 14 , 15 Nevertheless, there is no document to clarify the mechanism of ENKUR to modulate MYH9 in GC.…”

“…Subsequently, ENKUR has shown promising antitumor ability to decrease cell migration and invasion in lung adenocarcinoma and colorectal cancer 11,12 . Our recent studies also showed that the ENKUR was an important tumor suppressor and mediated the small molecule chemical compound cinobufotalin to inhibit tumor proliferation, metastasis, and chemoresistance in nasopharyngeal carcinoma, hepatocellular carcinoma, and lung adenocarcinoma 13–15 . However, the influence of the ENKUR on the biological function of GC and its related molecular mechanisms have not yet been studied.…”

CCDC65, a Gene Knockout that leads to Early Death of Mice, acts as a potentially Novel Tumor Suppressor in Lung Adenocarcinoma

“…The cycloheximide (CHX) chase assay and ubiquitination assay were performed as described previously [20,21]. Cells were treated with CHX (50 μg/mL) (Selleck, Shanghai, China) for Gradient time.…”

Recent insights into USP7: Construct, pathophysiology, and inhibitors

“…IFN is not toxic to the cell itself, but it inhibits the replication of a variety of viruses and possesses antitumor activity [142] . EZH2-CCF-cGAS signaling [129] MDM2/MDMX-p53 pathway [130] FBP1-DNMT1 pathway [131] NEDD4L-SMAD pathway [132] Cell cycle and EMT pathway [133] JMJD3/CLU signaling [81] p53/TfR1 pathway [134] Wnt/β-catenin signaling [39] PI3K/Akt pathway [124] Hippo pathway [107] Akt/ERK signaling [135] NF-κB signaling [136] AMPK pathway [124] Shh pathway [16] NOX4/NLRP3 pathway [137] Glucose Metabolism signaling [138] So×9-PTHrP-PTH1R axis [58] Insulin/IGF-1-like signaling [88] HIF-1α signaling pathway [139] Hedgehog signaling [140] Shoc2-ERK1/2 pathway [141] [143,144] . For example, in response to virus invasion, the body produces IFN, and the process is mediated by several factors.…”