Everolimus inhibits hepatoblastoma by inducing autophagy-dependent ferroptosis.

Everolimus, a known inhibitor of the mammalian target of rapamycin (mTOR), has shown uncertain efficacy in treating hepatoblastoma. This study delves into the potential anti-hepatoblastoma properties of everolimus and its intricate relationship with autophagy and ferroptosis, both in vitro and in vivo. In vivo, tumor tissue from hepatoblastoma patient and human hepatoblastoma cell line HuH-6 were xenografted into nude mice to establish xenograft models for observing the effect of everolimus on tumor growth. In vitro, HuH-6 cells were cultured to evaluate the anti-hepatoblastoma activity of everolimus. Transmission electron microscopy and microtubule-associated proteins 1 light chain 3 (LC3), beclin 1, and p62 protein expressions were employed to investigate autophagy. Additionally, indicators of cell apoptosis, reactive oxygen species (ROS) and proteins associated with ferroptosis were measured to evaluate ferroptosis. The results demonstrate that everolimus treatment effectively induced the formation of autophagosomes in hepatoblastoma cells, upregulated the LC3II/I ratio and beclin 1 expression, and downregulated p62 expression, indicating an enhanced autophagy level both in vitro and in vivo. Furthermore, everolimus treatment induced cell apoptosis, increased ROS level, elevated concentrations of malondialdehyde, 4-hydroxynonenal, and iron content, while reducing the ratio of glutathione/oxidized glutathione, and downregulating the protein expression of glutathione peroxidase 4 and solute carrier family 7 member 11, suggesting its ability to induce ferroptosis in hepatoblastoma cells. Importantly, the induction of ferroptosis by everolimus was significantly reversed in the presence of autophinib, an autophagy inhibitor, indicating the autophagy-dependent of everolimus-induced ferroptosis. Taken together, these findings suggest that everolimus holds promise as an effective anti-hepatoblastoma drug, with its mechanism of action potentially involving the induction of autophagy-dependent ferroptosis in hepatoblastoma cells.

Squalene Epoxidase: Its Regulations and Links with Cancers.

Squalene epoxidase (SQLE) is a key enzyme in the mevalonate-cholesterol pathway that plays a critical role in cellular physiological processes. It converts squalene to 2,3-epoxysqualene and catalyzes the first oxygenation step in the pathway. Recently, intensive efforts have been made to extend the current knowledge of SQLE in cancers through functional and mechanistic studies. However, the underlying mechanisms and the role of SQLE in cancers have not been fully elucidated yet. In this review, we retrospected current knowledge of SQLE as a rate-limiting enzyme in the mevalonate-cholesterol pathway, while shedding light on its potential as a diagnostic and prognostic marker, and revealed its therapeutic values in cancers. We showed that SQLE is regulated at different levels and is involved in the crosstalk with iron-dependent cell death. Particularly, we systemically reviewed the research findings on the role of SQLE in different cancers. Finally, we discussed the therapeutic implications of SQLE inhibitors and summarized their potential clinical values. Overall, this review discussed the multifaceted mechanisms that involve SQLE to present a vivid panorama of SQLE in cancers.

Systemic Analyses of Cuproptosis-Related lncRNAs in Pancreatic Adenocarcinoma, with a Focus on the Molecular Mechanism of LINC00853.

Pancreatic cancer (PC) is a deadly malignant digestive tumor with poor prognoses and a lack of effective treatment options. Cuproptosis, a recently identified copper-dependent programmed cell death type, has been implicated in multiple cancers. Long non-coding RNAs (lncRNAs) are also linked to the progression of PC. However, the role and prognostic values of cuproptosis-related lncRNAs in pancreatic adenocarcinoma (PAAD) remain unclear. In this study, we systemically analyzed the differential expressions and prognostic values of 672 cuproptosis-related lncRNAs in PAAD. Based on this, a prognostic signature including four lncRNAs (LINC00853, AC099850.3, AC010719.1, and AC006504.7) was constructed and was able to divide PAAD patients into high- and low-risk groups with significantly different prognoses. Next, we focused on lncRNA LINC00853. The differential expressions of LINC00853 between normal tissue and PAAD samples were validated by qRT-PCR. LINC00853 was knocked down by siRNA in PC cell lines BxPC-3 and PANC-1 and the oncogenic role of LINC00853 was validated by CCK8, colony formation, and EdU assays. Subsequently, LINC00853 knockdown cells were subjected to tumor xenograft tests and exhibited decreased tumor growth in nude mice. Mechanistically, knockdown of LINC00853 significantly reduced cellular glycolysis and enhanced cellular mitochondrial respiration levels in PC cells. Moreover, knockdown of LINC00853 decreased the protein level of a glycolytic kinase PFKFB3. Finally, glycolysis tests and functional tests using LINC00853 and HA-PFKFB3 indicated that the effects of LINC00853 on glycolysis and cell proliferation were mediated by PFKFB3. In conclusion, our systemic analyses have highlighted the important roles of cuproptosis-related lncRNAs in PAAD while the prognostic signature based on them showed excellent performance in PAAD patients and is expected to provide clinical guidance for individualized treatment. In addition, our findings provide a novel mechanism by which the LINC00853-PFKFB3 axis critically regulates aerobic glycolysis and cell proliferation in PC cells.

Establishment of childhood hepatoblastoma xenografts and evaluation of the anti-tumour effects of anlotinib, oxaliplatin and sorafenib.

BACKGROUND: Hepatoblastoma (HB) is a common primary malignant liver tumour in children, mainly treated by means of traditional chemotherapy using platinum and doxorubicin (ADM). There has been limited progress in the research and development of new drugs for treating HB. METHODS: A tumour biopsy from a child with HB was implanted into immunodeficient mice. The primary tumour and patient-derived xenograft (PDX) tumour were extensively characterised by histology, immunohistochemistry (IHC), and humanisation identification. We used the PDX model to evaluate the anti-tumour effects of anlotinib oxaliplatin (L-OHP) and sorafenib on childhood HB. RESULTS: The established PDX model maintained the histological characteristics of the primary tumour. Anlotinib, L-OHP, and sorafenib can significantly inhibit the tumour growth in the PDX model. There was no obvious damage of the drugs to the heart, liver and kidney of the mice, and the side effects observed were light. CONCLUSION: We have successfully established a PDX model of childhood HB. The model retains important molecular characteristics of human primary tumours. Using the model, it was found that anlotinib, L-OHP, and sorafenib have a good inhibitory effect on the growth of childhood HB. This provides a preliminary research basis for the clinical application of the drugs.

Ubiquitin-like protein FAT10 suppresses SIRT1-mediated autophagy to protect against ischemic myocardial injury.

Autophagy plays a deleterious role in ischemic myocardial injury. The deacetylase SIRT1 is a well-established regulator of autophagy that can be modified by the ubiquitin-like protein SUMO1. Our previous work demonstrated that another ubiquitin-like protein, FAT10, exerts cardioprotective effects against myocardial ischemia by stabilizing the caveolin-3 protein; however, the effects of FAT10 on autophagy through SIRT1 are unclear. Here, we constructed a Fat10-knockout rat model to evaluate the role of FAT10 in autophagy. In vivo and in vitro assays confirmed that FAT10 suppressed autophagy to protect the heart from ischemic myocardial injury. Mechanistically, FAT10 was mainly involved in the regulation of the autophagosome formation process. FAT10 affected autophagy through modulating SIRT1 degradation, which resulted in reduced SIRT1 nuclear translocation and inhibited SIRT1 activity via its C-terminal glycine residues. Notably, FAT10 competed with SUMO1 at the K734 modification site of SIRT1, which further reduced LC3 deacetylation and suppressed autophagy. Our findings suggest that FAT10 inhibits autophagy by antagonizing SIRT1 SUMOylation to protect the heart from ischemic myocardial injury. This is a novel mechanism through which FAT10 regulates autophagy as a cardiac protector.

The expression profiles and prognostic values of HSP70s in hepatocellular carcinoma.

BACKGROUND: The HSP70 family of heat shock protein plays a critical role in protein synthesis and transport to maintain protein homeostasis. Several studies have indicated that HSP70s are related to the development and occurrence of various cancers. METHODS: The relationship between the overall survival rate of hepatocellular carcinoma patients and the expression of 14 HSP70s from multiple databases, such as TCGA, ONCOMINE, cBioPortal was investigated. Western Blot and PCR were used to evaluate HSPA4 and HSPA14 expressions in various HCC cells to identify suitable cell lines for further experiments .Wound-healing assays, Transwell assays and EdU assays were used to verify the effects of HSPA4 and HSPA14 on the function of hepatocellular carcinoma cells, and statistical analysis was performed. RESULTS: Hepatocellular carcinoma tissues significantly expressed the 14 HSP70s compared to the normal samples. Besides, the high HSPA1A, HSPA1B, HSPA4, HSPA5, HSPA8, HSPA13, and HSPA14 expressions were inversely associated with the overall survival rate of patients, tumor grade, and cancer stage. A PPI regulatory network was constructed using the 14 HSP70s proteins with HSPA5 and HSPA8 at the network center. Univariate and multivariate analyses showed that HSPA4 and HSPA14 could be independent risk factors for the prognosis of hepatocellular carcinoma patients. Cell experiments have also confirmed that reducing HSPA4 and HSPA14 expressions can inhibit the invasion, metastasis, and proliferation of hepatocellular carcinoma cells. CONCLUSIONS: Therefore, the HSP70s significantly influence the occurrence and development of hepatocellular carcinoma. For instance, HSPA4 and HSPA14 can be novel therapeutic targets and prognostic biomarkers for hepatocellular carcinoma.

TAB3 upregulates PIM1 expression by directly activating the TAK1-STAT3 complex to promote colorectal cancer growth.

Transforming growth factor-ß-activated kinase 1 (TAK1)-binding protein 3 (TAB3) and the proviral integration site for Moloney murine leukaemia virus 1 (PIM1) are implicated in cancer development. In this study, we investigated the relationship between TAB3 and PIM1 in colorectal cancer (CRC) and determined the potential role and molecular mechanism of TAB3 in PIM1-mediated CRC growth. We found that TAB3 and PIM1 expression levels were positively correlated in CRC tissues. The knockdown of TAB3 significantly decreased PIM1 expression and inhibited CRC proliferation in vitro and in vivo. The upregulation of PIM1 rescued the decreased cell proliferation induced by TAB3 knockdown, whereas PIM1 knockdown decreased TAB3-enhanced CRC proliferation. Additionally, TAB3 regulates PIM1 expression through the STAT3 signalling pathway and confirmed a positive correlation between TAB3 and phosphorylated-STAT3 expression in CRC tissues. Patients with high expression of TAB3 and phosphorylated-STAT3 had the worst prognosis. Mechanistically, TAB3 regulates PIM1 expression by promoting STAT3 phosphorylation and activation through the formation of the TAB3-TAK1-STAT3 complex. Overall, a novel CRC regulatory circuit involving the TAB3-TAK1-STAT3 complex and PIM1 was identified, the dysfunction of which may contribute to CRC tumorigenesis.

GRP78 activates the Wnt/HOXB9 pathway to promote invasion and metastasis of hepatocellular carcinoma by chaperoning LRP6.

Recent studies have shown that the expression levels of glucose-regulated protein 78 (GRP78) and homeobox B9 (HOXB9) are both upregulated in hepatocellular carcinoma (HCC) and are closely related to HCC invasion and metastasis. However, whether there is a regulatory relationship between GRP78 and HOXB9 is unclear. In this study, we examined the expression of GRP78 and HOXB9 in HCC tissues and adjacent nontumor tissues. Correlation analysis indicated that GRP78 and HOXB9 expression were positively correlated. High levels of GRP78 and HOXB9 expression are closely related to worse clinicopathological features. Knockdown of GRP78 in HCC cells decreased the mRNA and protein expression of HOXB9, but increase HOXB9 expression reversed the decrease in invasion and metastasis induced by knocking down GRP78. Further experiments showed that GRP78 regulates HOXB9 through the Wnt signaling pathway by chaperoning low-density lipoprotein receptor-related protein 6 (LRP6). Importantly, we found that GPR78 promoted maturation of LRP6, while knockdown of GRP78 led to LRP6 misfolding and endoplasmic reticulum-associated degradation (ERAD). Consequently, the levels of mature LRP6 were reduced, and Wnt/HOXB9 signaling was inhibited. Our data suggest that the GRP78-LRP6-HOXB9 axis regulates the invasion and metastasis of HCC and may represent a potential therapeutic target for the treatment of HCC.

ROCK2 promotes osteosarcoma growth and metastasis by modifying PFKFB3 ubiquitination and degradation.

Rho-associated coiled-coil-containing protein kinase 2 (ROCK2) and 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) are widely involved in cell biological activities and play a key role in controlling various cell phenomena. However, the underlying mechanisms connecting ROCK2 and PFKFB3 in osteosarcoma growth and metastasis are poorly understood. In this study, we explored and analysed the role and molecular mechanism of ROCK2 and PFKFB3 in osteosarcoma. We analysed ROCK2 and PFKFB3 protein expression in 51 surgical specimens from osteosarcoma patients and determined the correlation between ROCK2 and PFKFB3. In addition, we used Transwell and wound-healing assays to detect cell invasion and migration and CCK8 and EdU assays to assess cell proliferation. Herein, we confirmed that ROCK2 and PFKFB3 proteins were significantly upregulated in osteosarcoma compared with adjacent normal tissues. Further studies revealed that knockdown of ROCK2 significantly decreased the expression levels of PFKFB3; moreover, growth and metastasis were decreased in shROCK2 osteosarcoma cells. Additionally, upregulation of PFKFB3 rescued the decreased proliferation and metastasis induced by ROCK2 knockdown, whereas knockdown of PFKFB3 decreased ROCK2-enhanced osteosarcoma proliferation and metastasis. These results suggest that PFKFB3 is essential for ROCK2-mediated proliferation and metastasis of osteosarcoma cells. Mechanistically, ROCK2 stabilizes PFKFB3 expression by modifying its ubiquitination and degradation. Taken together, our results link two drivers of proliferation and metastasis in osteosarcoma and identify a novel pathway for PFKFB3 regulation. Thus, we provide new evidence of the biological and clinical significance of PFKFB3 as a potential biomarker for osteosarcoma.

Ankyrin-B Q1283H Variant Linked to Arrhythmias Via Loss of Local Protein Phosphatase 2A Activity Causes Ryanodine Receptor Hyperphosphorylation.

BACKGROUND: Human loss-of-function variants of ANK2 (ankyrin-B) are linked to arrhythmias and sudden cardiac death. However, their in vivo effects and specific arrhythmogenic pathways have not been fully elucidated. METHODS: We identified new ANK2 variants in 25 unrelated Han Chinese probands with ventricular tachycardia by whole-exome sequencing. The potential pathogenic variants were validated by Sanger sequencing. We performed functional and mechanistic experiments in ankyrin-B knockin (KI) mouse models and in single myocytes isolated from KI hearts. RESULTS: We detected a rare, heterozygous ANK2 variant (p.Q1283H) in a proband with recurrent ventricular tachycardia. This variant was localized to the ZU5C region of ANK2, where no variants have been previously reported. KI mice harboring the p.Q1283H variant exhibited an increased predisposition to ventricular arrhythmias after catecholaminergic stress in the absence of cardiac structural abnormalities. Functional studies illustrated an increased frequency of delayed afterdepolarizations and Ca2+ waves and sparks accompanied by decreased sarcoplasmic reticulum Ca2+ content in KI cardiomyocytes on isoproterenol stimulation. The immunoblotting results showed increased levels of phosphorylated ryanodine receptor Ser2814 in the KI hearts, which was further amplified on isoproterenol stimulation. Coimmunoprecipitation experiments demonstrated dissociation of protein phosphatase 2A from ryanodine receptor in the KI hearts, which was accompanied by a decreased binding of ankyrin-B to protein phosphatase 2A regulatory subunit B56α. Finally, the administration of metoprolol or flecainide decreased the incidence of stress-induced ventricular arrhythmias in the KI mice. CONCLUSIONS: ANK2 p.Q1283H is a disease-associated variant that confers susceptibility to stress-induced arrhythmias, which may be prevented by the administration of metoprolol or flecainide. This variant is associated with the loss of protein phosphatase 2A activity, increased phosphorylation of ryanodine receptor, exaggerated delayed afterdepolarization-mediated trigger activity, and arrhythmogenesis.

Human Leukocyte Antigen F Locus Adjacent Transcript 10 Overexpression Disturbs WISP1 Protein and mRNA Expression to Promote Hepatocellular Carcinoma Progression.

Recently, studies on transcriptome-proteome relationships have revealed mRNA/protein expression discordance for certain genes and speculated that protein posttranslational modification (PTM) may be involved. However, there is currently no evidence to support this hypothesis. Wnt-induced secreted protein-1 (WISP1) is the downstream target gene of ß-catenin and plays an important role in tumorigenesis and progression, but the expression and role of WISP1 in different tumor types are controversial. Here, we first confirmed that WISP1 protein expression was significantly down-regulated in hepatocellular carcinoma (HCC) tissue and could be an independent predictor of poor prognosis for patients with HCC. In vivo and in vitro evidence was provided that WISP1 can suppress HCC cell proliferation. Further studies have found that low WISP1 protein expression was related to expression of human leukocyte antigen F locus adjacent transcript 10 (FAT10), a specific ubiquitin-like protein with both degradation and stabilization functions, which plays an important role in PTM. FAT10 overexpression facilitated WISP1 degradation by FAT10ylation to decrease WISP1 protein expression, thus promoting HCC proliferation. Interestingly, we found and demonstrated that FAT10 overexpression could result in WISP1 protein/mRNA expression discordance, with protein expression decreasing while mRNA expression increased. The underlying mechanism is that FAT10 exerts substrate stabilization and degradation functions simultaneously, while FAT10 overexpression promotes WISP1 mRNA expression by stabilizing ß-catenin and directly degrades WISP1 protein. Conclusion: Our study demonstrated that overexpression of FAT10 results in expression discordance between WISP1 protein and mRNA, thereby promoting HCC progression by down-regulating WISP1 protein expression.

GRP78 Promotes Hepatocellular Carcinoma proliferation by increasing FAT10 expression through the NF-κB pathway.

Glucose-regulated protein 78(GRP78) and the ubiquitin-like protein FAT10 each promote proliferation in hepatocellular carcinoma(HCC). However, the relationship of GRP78 and FAT10 in HCC proliferation are still not known. In this study, we found that GRP78 and FAT10 were significantly overexpressed in HCC tissues compare with adjacent non-cancerous tissues, and a positive correlation was found between their expression and associated proliferation characteristics. High expression of GRP78 and FAT10 were positively correlated with tumor proliferation and poor prognosis in HCC. Moreover, GRP78 knockdown reduced FAT10 expression and suppressed HCC proliferation in vitro and in vivo. The effects of GRP78 knockdown were rescued by FAT10 up-regulation, whereas FAT10 knockdown reduced HCC proliferation enhanced by GRP78 up-regulation. Furthermore, GRP78 modulated FAT10 expression by regulating the NF-κB pathway, direct activation of the NF-κB pathway increased the expression of FAT10, a gene counteracting the tumor suppressor p53. Taken together, these results suggest that this newly identified GRP78-NF-κB-FAT10 axis will provide novel insight into the understanding of the regulatory mechanisms of proliferation in human HCC.

FAT10 attenuates hypoxia-induced cardiomyocyte apoptosis by stabilizing caveolin-3.

FAT10, a member of the ubiquitin-like-modifier family of proteins, plays a cardioprotective role in response to hypoxic/ischemic injury. Caveolin-3 (Cav-3), a muscle-specific caveolin family member, is involved in cardiomyocyte apoptosis. However, the link between FAT10 and Cav-3 in ischemic cardiomyocytes is unclear. In the present study, we found that both FAT10 and Cav-3 were upregulated in ischemic myocardial tissues and in hypoxic cardiomyocytes. Furthermore, our results demonstrated that FAT10 inhibits hypoxia-induced cardiomyocyte apoptosis by increasing Cav-3 expression. Importantly, following myocardial infarction, knockout of FAT10 aggravated cardiac dysfunction and increased cardiomyocyte apoptosis by reducing Cav-3 expression. Additionally, Cav-3 was degraded by the ubiquitin-proteasome system (UPS) in cardiomyocytes. Mechanistically, we found that FAT10 stabilizes Cav-3 expression by inhibiting ubiquitination-mediated degradation in cardiomyocytes. Together, these findings revealed a novel role of FAT10 in protection against ischemia-induced injury via stabilization of Cav-3, providing evidence that the FAT10/Cav-3 axis may be a potential therapeutic target for patients with ischemic heart conditions.

Overexpression of eEF1A1 regulates G1-phase progression to promote HCC proliferation through the STAT1-cyclin D1 pathway.

Hepatocellular carcinoma (HCC) is a common cancer worldwide with an aggressive and highly proliferative activity. Studies had confirmed that HCC cell proliferation is associated with the cell cycle's G1 phase, but the detailed molecular mechanism has not been thoroughly elucidated to date. Eukaryotic translation elongation factor 1A1 (eEF1A1) is an evolutionarily conserved elongation factor protein and is involved in tumor cell proliferation. However, which phase of the cell cycle is regulated by eEF1A1 to influence cell proliferation in HCC and its detailed molecular mechanism remain unclear. In this study, we observed that eEF1A1 influences HCC cell proliferation by regulating the cell cycle's G1 phase. In addition, eEF1A1 influences G1 phase by regulating cyclin D1 expression, promoting HCC cell proliferation both in vitro and in vivo. Moreover, our results indicated that eEF1A1 regulates cyclin D1 expression through STAT1 signaling. STAT1 increases the transcriptional activity of cyclin D1 by binding to the cyclin D1 promoter. Taken together, these findings enabled us to identify a novel mechanism by which eEF1A1 regulates the cell cycle's G1 phase to promote tumor proliferation by regulating cyclin D1 expression through STAT1 signaling in HCC.

Carborane Derivative Conjugated with Gold Nanoclusters for Targeted Cancer Cell Imaging.

Polyhedral borane derivatives have been utilized in the treatment of boron neuron capture therapy (BNCT) for brain glioma, and much attention has been paid to search excellent biocompatible boron-rich composites for effective cancer BNCT therapy. In this study, we have exploited the self-assembly of the gold nanoclusters with carborane amino derivatives (GNCs-CB) for the precise bioimaging of cancer cells and targeted delivery of this carborane compound to the tumors. Our observations demonstrate that the GNCs-CB can readily realize accurate tumor imaging and long-term accumulation in tumor sites by EPR effect and nanometer size effect, and thus efficiently implement tumor-targeting delivery of the carborane derivative and facilitate the real-time fluorescent visualization monitoring of the carborane targeted delivery process. This makes it possible to realize the accurate location of the tumor by the carborane derivative and reduce the damage to normal tissues in the process of boron neutron capture therapy through imaging guided treatment.

Rock2 promotes RCC proliferation by decreasing SCARA5 expression through ß-catenin/TCF4 signaling.

Rho-associated coiled-coil forming protein kinase 2 (Rock2), as a key effector of the small GTPase RhoA, is involved in tumor development. Scavenger receptor class A member 5 (SCARA5) is an important regulator of biological processes in cancer cells. However, the roles and relationship of Rock2 and SCARA5 in renal cell carcinoma (RCC) remain unclear. In this study, we found that Rock2 expression was markedly increased in clinical RCC tissues compared with that in adjacent non-cancerous tissues. High expression of Rock2 was inversely correlated with patient survival in RCC, which indicated that Rock2 may be a prognostic marker in human RCC. In addition, Rock2 knockdown increased SCARA5 expression and suppressed RCC cell proliferation both in vitro and in vivo. Furthermore, we found that the ß-catenin/TCF4 pathway contributed to the effect of Rock2 on SCARA5-mediated RCC proliferation. Taken together, these results suggest that this newly identified Rock2-ß-catenin/TCF4-SCARA5 axis will provide novel insight into the understanding of the regulatory mechanisms of proliferation in human RCC.

Rock2 stabilizes ß-catenin to promote tumor invasion and metastasis in colorectal cancer.

Rho-associated coiled-coil-containing protein kinase 2 (Rock2) is an effector for the small GTPase Rho and plays an important role in tumor progression and metastasis. However, the effect of Rock2 in colorectal cancer (CRC) still remains unclear. In this study, we found that Rock2 expression was markedly increased in clinical CRC tissues compared with adjacent non-cancerous tissues. High expression of Rock2 was correlated with tumor metastasis and poor prognosis in CRC. In addition, the knockdown of Rock2 suppressed the invasion and metastasis of CRC cells both in vitro and in vivo. Furthermore, we found that the ß-catenin/TCF4 pathway contributed to the effects of Rock2 in CRC cells, and Rock2 stabilized ß-catenin by preventing its ubiquitination and degradation. Taken together, this novel pathway for ß-catenin control plays a biologically relevant role in CRC metastasis.

Rock2 promotes the invasion and metastasis of hepatocellular carcinoma by modifying MMP2 ubiquitination and degradation.

Rho-associated coiled-coil-containing protein kinase 2 (Rock2) is a downstream effector of Rho that plays an important role in the tumorigenesis and progression of hepatocellular carcinoma (HCC). Matrix metalloproteinase 2 (MMP2) is a master regulator of tumor metastasis. In this study, we investigated the collections of Rock2 and MMP2 in HCCs and determined the potential role and molecular mechanism of Rock2 in MMP2-mediated invasiveness and metastasis. We found that Rock2 and MMP2 were markedly overexpressed in HCCs compared with the corresponding adjacent tissues, where a positive correlation in their expression was found. The knockdown of Rock2 significantly decreased MMP2 expression and inhibited the invasion and metastasis of HCC in vitro and in vivo. Additionally, the upregulation of MMP2 rescued the decreased migration and invasion induced by the knockdown of Rock2, whereas the knockdown of MMP2 decreased Rock2-enhanced HCC migration and invasion. Mechanistically, Rock2 stabilized MMP2 by preventing its ubiquitination and degradation. Together, our results link two drivers of invasion and metastasis in HCC and identify a novel pathway for MMP2 control.

Ubiquitin-specific protease 54 regulates GLUT1-mediated aerobic glycolysis to inhibit lung adenocarcinoma progression by modifying p53 degradation.

Lung adenocarcinoma (LUAD) is one of the most prevalent types of cancer. Ubiquitination is crucial in modulating cell proliferation and aerobic glycolysis in cancer. The frequency of TP53 mutations in LUAD is approximately 50%. Currently, therapeutic targets for wild-type (WT) p53-expressing LUAD are limited. In the present study, we systemically explored the expression of ubiquitin-specific protease genes using public datasets. Then, we focused on ubiquitin-specific protease 54 (USP54), and explored its prognostic significance in LUAD patients using public datasets, analyses, and an independent cohort from our center. We found that the expression of USP54 was lower in LUAD tissues compared with that in the paracancerous tissues. Low USP54 expression levels were linked to a malignant phenotype and worse survival in patients with LUAD. The results of functional experiments revealed that up-regulation of USP54 suppressed LUAD cell proliferation in vivo and in vitro. USP54 directly interacted with p53 protein and the levels of ubiquitinated p53 were inversely related to USP54 levels, consistent with a role of USP54 in deubiquitinating p53 in p53-WT LUAD cells. Moreover, up-regulation of the USP54 expression inhibited aerobic glycolysis in LUAD cells. Importantly, we confirmed that USP54 inhibited aerobic glycolysis and the growth of tumor cells by a p53-mediated decrease in glucose transporter 1 (GLUT1) expression in p53-WT LUAD cells. Altogether, we determined a novel mechanism of survival in the p53-WT LUAD cells to endure the malnourished tumor microenvironment and provided insights into the role of USP54 in the adaptation of p53-WT LUAD cells to metabolic stress.

FAT10 mediates the sorafenib-resistance of hepatocellular carcinoma cells by stabilizing E3 ligase NEDD4 to enhance PTEN/AKT pathway-induced autophagy.

Although sorafenib is the first-line therapeutic agent for advanced hepatocellular carcinoma (HCC), the development of drug resistance in HCC cells limits its clinical efficacy. However, the key factors involved in mediating the sorafenib resistance of HCC cells and the underlying mechanisms have not been elucidated. In this study, we generated sorafenib-resistant HCC cell lines, and our data demonstrate that HLA-F locus-adjacent transcript 10 (FAT10), a ubiquitin-like protein, is markedly upregulated in sorafenib-resistant HCC cells and that reducing the expression of FAT10 in sorafenib-resistant HCC cells increases sensitivity to sorafenib. Mechanistically, FAT10 stabilizes the expression of the PTEN-specific E3 ubiquitin ligase NEDD4 that causes downregulation of PTEN, thereby inducing AKT-mediated autophagy and promoting the resistance of HCC cells to sorafenib. Moreover, we screened the small molecule Compound 7695-0983, which increases the sensitivity of sorafenib-resistant HCC cells to sorafenib by inhibiting the expression of FAT10 to inhibit NEDD4-PTEN/AKT axis-mediated autophagy. Collectively, our preclinical findings identify FAT10 as a key factor in the sorafenib resistance of HCC cells and elucidate its underlying mechanism. This study provides new mechanistic insight for the exploitation of novel sorafenib-based tyrosine kinase inhibitor (TKI)-targeted drugs for treating advanced HCC.