The stage-dependent prognostic role of ARID1A in hepatocellular carcinoma.

Background: Hepatocellular carcinoma (HCC) is one of the most common causes of cancer-related death. Although novel treatment currently achieves a better response, the majority of HCC patients develop resistance and cannot benefit. Hence, novel biomarkers for guiding therapy and predicting the prognosis are needed. Methods: Tissue microarrays of 206 HCC patients were used, and ARID1A expression was determined by immunohistochemistry. Databases were used for the verification and expansion of our results. The "rms" package of R software was used for the construction of the nomogram. Results: ARID family alterations were associated with disease-free survival (P=0.0325) and overall survival (OS) (P=0.0076). Subgroup analysis confirmed the prognostic effect of ARID1A, ARID1B, and ARID2 alterations. In addition, ARID family genomic alterations, especially ARID1A, were closely related to poor progression-free survival (ARID: P=0.0011; ARID1A: P=0.0082) and OS (ARID: P=0.0161; ARID1A: P=0.0220) after sorafenib treatment. ARID1A expression was found to display a stage-dependent effect on the prognosis, serving as a risk factor in stage I-II patients (P<0.0001) and a protective factor in stage III-IV patients (P=0.0180). Conclusions: ARID1A has dual roles in HCC in a tumor stage-dependent manner, and further study is required to uncover the complex function of ARID1A in HCC development, disease progression, and therapy.

RIT1 regulates mitosis and promotes proliferation by interacting with SMC3 and PDS5 in hepatocellular carcinoma.

BACKGROUND: As a small G protein of Ras family, Ras-like-without-CAAX-1 (RIT1) plays a critical role in various tumors. Our previous study has demonstrated the involvement of RIT1 in promoting malignant progression of hepatocellular carcinoma (HCC). However, its underlying mechanism remains unclear. METHODS: Gene set enrichment analysis (GSEA) was conducted in the TCGA LIHC cohort to investigate the underlying biological mechanism of RIT1. Live cell imaging, immunofluorescence (IF) and flow cytometry assays were used to verify biological function of RIT1 in HCC mitosis. Subcutaneous xenografting of human HCC cells in BALB/c nude mice was utilized to assess tumor proliferation in vivo. RNA-seq, co-immunoprecipitation (Co-IP), mass spectrometry analyses, western blot and IF assays were employed to elucidate the mechanisms by which RIT1 regulates mitosis and promotes proliferation in HCC. RESULTS: Our findings demonstrate that RIT1 plays a crucial role in regulating mitosis in HCC. Knockdown of RIT1 disrupts cell division, leading to G2/M phase arrest, mitotic catastrophe, and apoptosis in HCC cells. SMC3 is found to interact with RIT1 and knockdown of SMC3 attenuates the proliferative effects mediated by RIT1 both in vitro and in vivo. Mechanistically, RIT1 protects and maintains SMC3 acetylation by binding to SMC3 and PDS5 during mitosis, thereby promoting rapid cell division and proliferation in HCC. Notably, we have observed an upregulation of SMC3 expression in HCC tissues, which is associated with poor patient survival and promotion of HCC cell proliferation. Furthermore, there is a significant positive correlation between the expression levels of RIT1, SMC3, and PDS5. Importantly, HCC patients with high expression of both RIT1 and SMC3 exhibit worse prognosis compared to those with high RIT1 but low SMC3 expression. CONCLUSIONS: Our findings underscore the crucial role of RIT1 in regulating mitosis in HCC and further demonstrate its potential as a promising therapeutic target for HCC treatment.

Syntaxin-6 promotes the progression of hepatocellular carcinoma and alters its sensitivity to chemotherapies by activating the USF2/LC3B axis.

Syntaxin-6 (STX6), a protein of the syntaxin family, is located in the trans-Golgi network and is involved in a variety of intracellular membrane transport events. STX6 is overexpressed in different human malignant tumors. However, little is known about its exact function and molecular mechanism in hepatocellular carcinoma (HCC). In this study, we found that the expression of STX6 was significantly increased in HCC tissues and was associated with poor survival. Gain- and loss-of-function experiments showed that STX6 promotes cell proliferation and metastasis of HCC cells both in vitro and in vivo. Mechanistically, STX6 was negatively regulated by the upstream stimulatory factor 2 (USF2). In addition, STX6 facilitates the association of autophagosomes with lysosomes. Importantly, we demonstrated that STX6 overexpression, despite enhanced resistance to lenvatinib, sensitizes HCC cells to the autophagy activator rapamycin. This study revealed that, under the control of USF2, STX6 accelerates the degradation of microtubule-associated protein 1 light chain 3 beta (LC3) by promoting autophagic flux, ultimately promoting HCC progression. Collectively, we suggest that the USF2-STX6-LC3B axis is a potential therapeutic target in liver cancer.

Drug Repurposing Flubendazole to Suppress Tumorigenicity via PCSK9-dependent Inhibition and Potentiate Lenvatinib Therapy for Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is one of the most lethal malignant cancers across the world. It has a poor prognosis and lacks effective therapies, especially for patients with advanced-stage cancer, indicating an urgent need for new therapies and novel therapeutic targets. Here, by screening the U.S. Food and Drug Administration drug library against HCC cell lines, we identified that flubendazole, a traditional anthelmintic drug, could prominently suppress HCC cells in vivo and in vitro. RNA sequence analysis and cellular thermal shift assays showed that flubendazole reduced the expression of PCSK9 protein by direct targeting. The increased expression of PCSK9 in HCC tissues was demonstrated to be correlated with poor prognosis, and the inhibitory ability of flubendazole was selectively dependent on PCSK9 expression. PCSK9 knockdown abolished the antitumor effects of flubendazole in HCC. Mechanistically, flubendazole inhibited the Hedgehog signaling pathway induced by PCSK9, resulting in the downregulation of smoothened (SMO) and GLI Family Zinc Finger 1 (Gli1). Moreover, combining flubendazole with lenvatinib was found more effective than administering lenvatinib only for HCC treatment in vivo and in vitro. These findings reveal the therapeutic potential of flubendazole against HCC and provide clues on new repurposed drugs and targets for cancer treatment.

Sex Differences in Genomic Features of Hepatitis B-Associated Hepatocellular Carcinoma With Distinct Antitumor Immunity.

BACKGROUND & AIMS: Aflatoxin exposure increases the risk for hepatocellular carcinoma (HCC) in hepatitis B virus (HBV)-infected individuals, particularly males. We investigated sex-based differences in the HCC genome and antitumor immunity. METHODS: Whole-genome, whole-exome, and RNA sequencing were performed on 101 HCC patient samples (47 males, 54 females) that resulted from HBV infection and aflatoxin exposure from Qidong. Androgen on the expression of aflatoxin metabolism-related genes and nonhomologous DNA end joining (NHEJ) factors were examined in HBV-positive HCC cell lines, and further tested in tumor-bearing syngeneic mice. RESULTS: Qidong HCC differed between males and females in genomic landscape and transcriptional dysfunction pathways. Compared with females, males expressed higher levels of aflatoxin metabolism-related genes, such as AHR and CYP1A1, and lower levels of NHEJ factors, such as XRCC4, LIG4, and MRE11, showed a signature of up-regulated type I interferon signaling/response and repressed antitumor immunity. Treatment with AFB1 in HBV-positive cells, the addition of 2 nmol/L testosterone to cultures significantly increased the expression of aflatoxin metabolism-related genes, but reduced NHEJ factors, resulting in more nuclear DNA leakage into cytosol to activate cGAS-STING. In syngeneic tumor-bearing mice that were administrated tamoxifen daily via oral gavage, favorable androgen signaling repressed NHEJ factor expression and activated cGAS-STING in tumors, increasing T-cell infiltration and improving anti-programmed cell death protein 1 treatment effect. CONCLUSIONS: Androgen signaling in the context of genotoxic stress repressed DNA damage repair. The alteration caused more nuclear DNA leakage into cytosol to activate the cGAS-STING pathway, which increased T-cell infiltration into tumor mass and improved anti-programmed cell death protein 1 immunotherapy in HCCs.

FBXO9 Mediates the Cancer-Promoting Effects of ZNF143 by Degrading FBXW7 and Facilitates Drug Resistance in Hepatocellular Carcinoma.

F-box proteins are critical for malignancy because they control the turnover of key proteins that govern multiple cellular processes. F-box protein 9 (FBXO9) belongs to the F-box protein family and exhibits oncogenic properties in hematological malignancies. However, the function and molecular mechanism of FBXO9 in hepatocellular carcinoma (HCC) remain unclear. Here, we report that FBXO9 was remarkably overexpressed in HCC. Loss- and gain-of-function experiments showed that FBXO9 facilitates HCC cell proliferation and metastasis both in vitro and in vivo. Mechanistically, as a direct upstream transcription factor, FBXO9 is regulated by zinc finger protein 143 (ZNF143) and accelerates tumor growth and metastasis by targeting the F-box and WD repeat domain containing 7 (FBXW7) for ubiquitination and degradation. Additionally, we found that with FBXO9 knockdown, HCC cells were more sensitive to treatment with lenvatinib and sorafenib. In summary, our results demonstrate that a ZNF143-FBXO9-FBXW7 signaling regulatory axis may be involved in tumor progression in HCC, and suggest that FBXO9 could be a potential biomarker and therapeutic target for HCC.

STAT5A modulates CDYL2/SLC7A6 pathway to inhibit the proliferation and invasion of hepatocellular carcinoma by targeting to mTORC1.

Chromodomain Y-like 2 (CDYL2), as a member of CDY family known to be involved in spermatogenesis, has been reported to participate in breast cancer development recently, but its exact biological role in hepatocellular carcinoma (HCC) remains unclear. Here, we observed that CDYL2 was down-regulated in human primary HCC tissues and the low levels of CDYL2 expression were correlated with poor survival. Gain- and loss-of-function experiments showed that CDYL2 inhibited the proliferation and metastasis of HCC cells in vitro and in vivo. Mechanistically, CDYL2 down-regulates solute carrier family 7 member 6 (SLC7A6) by decreasing the enrichment of H3K4me3 on the promoter region of SLC7A6. Additionally, we also found that signal transducer and activator of transcription 5A (STAT5A) could directly and positively regulate the expression of CDYL2. Thus, CDYL2 was regulated by STAT5A, and suppressed the amino acid transportation through down-regulation of SLC7A6, and then inhibits the mTORC1/S6K pathway, a master regulator of cell growth. Consistently, CDYL2 expression correlated significantly with STAT5A and SLC7A6 expression in HCC. Collectively, we propose a model for a STAT5A/CDYL2/SLC7A6 axis that provides novel insight into CDYL2, which may serve as a potential factor for predicting prognosis and a therapeutic target for HCC patients.

Long term outcome of prevention of liver cancer by hepatitis B vaccine: Results from an RCT with 37 years.

We aimed to evaluate the long-term efficacy of the hepatitis B vaccine in China. In an initial efficacy study, participants were collected from a cluster-randomized clinical trial conducted in 1983-90 in Qidong. All the participants in the vaccination group were vaccinated at birth, 1 and 6 months of age, and no intervention was implemented to the control group. In this 37-year extended follow-up study, the Poisson regression method was employed to derive rates per 105 person-years. The frailty Cox proportional hazard regression models obtained the hazard ratio (HR). Cumulative incidence/mortality rates were calculated and compared with log-rank tests. 41,136 in the vaccination and 41,730 in the control group were recorded. The incidence rate of liver cancer was significantly lower in the vaccinated group than in the control group [HR, 0.28; 95% confidence interval (CI) 0.11-0.70, P = 0.007]. The vaccine offers 72% (95% CI, 30-89) protection to prevent the occurrence of liver cancer. There is 70% (95% CI, 23-88) protective efficacy against liver cancer deaths and 64% (95% CI, 27-82) benefits in the prevention of deaths associated with liver diseases. Hepatitis B vaccine given at birth shows excellent protective effects in preventing the development of liver cancer and reducing mortality from liver cancer and liver diseases.

Sperm associated antigen 4 promotes SREBP1-mediated de novo lipogenesis via interaction with lamin A/C and contributes to tumor progression in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a highly malignant tumor and its progression is associated with altered lipid metabolism in precancerous lesions, such as non-alcoholic fatty liver disease. Here, we identified sperm associated antigen 4 (SPAG4), and explored its oncogenic role in HCC progression. Database analysis and immunohistochemistry indicated increased level of SPAG4 in HCC tissues which was of prognostic value. Gain/loss-of-function experiments showed that SPAG4 exerted oncogenic roles in HCC growth both in vitro and in vivo. RNA sequencing revealed activation of a lipogenic state and SREBP1-mediated pathway following SPAG4 overexpression. Mechanistically, the N-terminal region of SPAG4 bound to lamin A/C, which increased SREBP1 expression, nuclear translocation, and transcriptional activity. Treatment with orlistat, a lipid synthesis inhibitor, reversed SPAG4-mediated oncogenic effects, and its efficacy varied with SPAG4 level. The effect of orlistat was further amplified when combined with sorafenib in tumor xenograft mouse models. Our study provides evidence that SPAG4 mediates HCC progression by affecting lipid metabolism. Administration of orlistat combined with sorafenib reverses SPAG4-mediated oncogenesis in HCC cells and ectopic xenograft tumors in mice, suggesting that this pathway represents a potential target for HCC treatment.

B-Cell Receptor-Associated Protein 31 Promotes Metastasis via AKT/ß-Catenin/Snail Pathway in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is one of the most lethal cancer worldwide, characterized with high heterogeneity and inclination to metastasize. Emerging evidence suggests that BAP31 gets involved in cancer progression with different kinds. It still remains unknown whether and how BAP31 plays a role in HCC metastasis. Epithelial-mesenchymal transition (EMT) has been a common feature in tumor micro-environment, whose inducer TGF-ß increased BAP31 expression in this research. Elevated expression of BAP31 was positively correlated with tumor size, vascular invasion and poor prognosis in human HCC. Ectopic expression of BAP31 promoted cell migration and invasion while BAP31 knockdown markedly attenuated metastatic potential in HCC cells and mice orthotopic xenografts. BAP31 induced EMT process, and enhanced the expression level of EMT-related factor Snail and decreased contents and membrane distribution of E-cadherin. BAP31 also activated AKT/ß-catenin pathway, which mediated its promotional effects on HCC metastasis. AKT inhibitor further counteracted the activated AKT/ß-catenin/Snail upon BAP31 over-expression. Moreover, silencing Snail in BAP31-overexpressed cells impaired enhanced migratory and invasive abilities of HCC cells. In HCC tissues, BAP31 expression was positively associated with Snail. In conclusion, BAP31 promotes HCC metastasis by activating AKT/ß-catenin/Snail pathway. Thus, our study implicates BAP31 as potential prognostic biomarker, and provides valuable information for HCC prognosis and treatment.

Neonatal hepatitis B vaccination protects mature adults from occult virus infection.

BACKGROUND: Among elder children/young adults who received hepatitis B virus (HBV) vaccination during infancy, the serological status of HBsAg-negative and anti-HBc-positive [HBsAg(-)/anti-HBc(+)] was frequently reported, indicating potential occult HBV infection (OBI). It is required to define the long-term protection of neonatal vaccination against OBI in their mature adulthood. METHODS: Building upon the 1983-1990 established Qidong Hepatitis B Intervention Study, we sampled 10% of the 28-35-year-old participants, who remained in the cohort by 2012. Each participant was tested for serological markers of HBsAg, anti-HBs, HBeAg, anti-HBe and anti-HBc. HBV-DNA and relaxed circular DNA (rcDNA) were determined in some HBsAg(-)/anti-HBc(+) individuals. RESULTS: Totally, 3615 individuals from the neonatal vaccination group and 3100 individuals from the control group donated blood samples, respectively. In the vaccination group, the prevalence of HBsAg was 1.58% (57/3615), HBsAg(-)/anti-HBc(+) was 4.70% (170/3615), significantly lower than in the control group, which was 7.45% (231/3100) and 19.48% (640/3100) respectively (all p < 0.001). With aging, HBsAg(-)/anti-HBc(+) prevalence increased in the sampled participants from the control group (pfor trend < 0.001), but uncertain from the vaccination group. Of HBsAg(-)/anti-HBc(+), HBV-DNA was detected in 13.08% (17/130) from the vaccination group, and in 4.18% (12/287) from the control group. HBV rcDNA was detected in most sera that were tested positive for HBV-DNA. CONCLUSIONS: OBI occurred in some vaccinated adults. However, neonatal HBV vaccination kept the effective protection against OBI in mature adults.

A Positive Feedback Loop of AKR1C3-Mediated Activation of NF-κB and STAT3 Facilitates Proliferation and Metastasis in Hepatocellular Carcinoma.

AKR1C3 is an enzyme belonging to the aldo-ketoreductase family, the members of which catalyze redox transformations involved in biosynthesis, intermediary metabolism, and detoxification. AKR1C3 plays an important role in tumor progression and metastasis, however, little is known about the function and the molecular mechanism underlying the role of AKR1C3 in hepatocellular carcinoma (HCC). In this study, we report that AKR1C3 is significantly upregulated in HCC and that increased AKR1C3 is associated with poor survival. AKR1C3 positively regulated HCC cell proliferation and metastasis in vitro and in vivo. AKR1C3 promoted tumor proliferation and metastasis by activating NF-κB signaling. Furthermore, AKR1C3 regulated NF-κB activity by modulating TRAF6 and inducing its autoubiquitination in HCC cells. Activation of NF-κB released proinflammatory factors that facilitated the phosphorylation of STAT3 and increased tumor cell proliferation and invasion. Gain- and loss-of-function experiments showed that AKR1C3 promoted tumor proliferation and invasion via the IL6/STAT3 pathway. STAT3 also directly bound the AKR1C3 promoter and increased transcription of AKR1C3, thereby establishing a positive regulatory feedback loop. Treatment with the AKR1C3 inhibitors indocin and medroxyprogesterone acetate inhibited tumor growth and invasion and promoted apoptosis in HCC cells. Collectively, these results indicate that a AKR1C3/NF-κB/STAT3 signaling loop results in HCC cell proliferation and metastasis and could be a promising therapeutic target in HCC. SIGNIFICANCE: These findings elucidate a novel AKR1C3-driven signaling loop that regulates proliferation and metastasis in HCC, providing potential prognostic and therapeutic targets in this disease.

Correction: Upregulation of SNX5 predicts poor prognosis and promotes hepatocellular carcinoma progression by modulating the EGFR-ERK1/2 signaling pathway.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

TP53 R249S mutation detected in circulating tumour DNA is associated with Prognosis of hepatocellular carcinoma patients with or without hepatectomy.

BACKGROUND AND AIMS: Somatic mutation R249S in TP53 is highly common in hepatocellular carcinoma (HCC). We aim to investigate the effects of R249S in ctDNA on the prognosis of HCC. METHODS: We analysed three cohorts including 895 HCC patients. TP53 mutation spectrum was examined by direct sequencing of genomic DNA from tissue specimens in HCC patients with hepatectomy (Cohort 1, N = 260). R249S and other recurrent missense mutations were assessed for their biological functions and associations with overall survival (OS) and progression-free survival (PFS) of HCC patients in Cohort 1. R249S within circulating tumour DNA (ctDNA) was detected through droplet digital polymerase chain reaction (ddPCR) and its association with OS and PRS was analysed in HCC patients with (Cohort 2, N = 275) or without (Cohort 3, N = 360) hepatectomy. RESULTS: In Cohort 1, R249S occupied 60.28% of all TP53 mutations. Overexpression of R249S induced more serious malignant phenotypes than those of the other three identified TP53 recurrent missense mutations. Additionally, R249S, but not other missense mutations, was significantly associated with worse OS (P = .006) and PFS (P = .01) of HCC patients. Consistent with the results in Cohort 1, HCC patients in Cohorts 2 and 3 with R249S had worse OS (P = 8.291 × 10-7 and 2.608 × 10-7 in Cohorts 2 and 3, respectively) and PFS (P = 5.115 × 10-7 and 5.900 × 10-13 in Cohorts 2 and 3, respectively) compared to those without this mutation. CONCLUSIONS: TP53 R249S mutation in ctDNA may serve as a promising prognosis biomarker for HCC patients with or without hepatectomy.

ZNF143-Mediated H3K9 Trimethylation Upregulates CDC6 by Activating MDIG in Hepatocellular Carcinoma.

Zinc finger protein 143 (ZNF143) belongs to the zinc finger protein family and possesses transcription factor activity by binding sequence-specific DNA. The exact biological role of ZNF143 in hepatocellular carcinoma (HCC) has not been investigated. Here we report that ZNF143 is overexpressed in HCC tissues and its overexpression correlates with poor prognosis. Gain- and loss-of-function experiments showed that ZNF143 promoted HCC cell proliferation, colony formation, and tumor growth in vitro and in vivo. ZNF143 accelerated HCC cell-cycle progression by activating cell division cycle 6 (CDC6). Mechanistically, ZNF143 promoted expression of CDC6 by directly activating transcription of histone demethylase mineral dust-induced gene (MDIG), which in turn reduced H3K9me3 enrichment in the CDC6 promoter region. Consistently, ZNF143 expression correlated significantly with MDIG and CDC6 expression in HCC. Collectively, we propose a model for a ZNF143-MDIG-CDC6 oncoprotein axis that provides novel insight into ZNF143, which may serve as a therapeutic target in HCC. SIGNIFICANCE: These findings describe the mechanism by which ZNF143 promotes HCC proliferation and provide important clues for exploring new targets and strategies for clinical treatment of human liver cancer.

Upregulation of SNX5 predicts poor prognosis and promotes hepatocellular carcinoma progression by modulating the EGFR-ERK1/2 signaling pathway.

Endocytosis is an essential component of cell motility, which facilitates the malignant behavior of cancer. Sorting nexin (SNX) family members are associated with tumor progression. However, the role and mechanism of SNX5 in hepatocellular carcinoma (HCC) progression remain largely unknown. In this study, we investigated the clinical significance and possible involvement of SNX5 in the progression of HCC. Here, we showed that SNX5 was upregulated in tumors compared with adjacent nontumorous tissues in HCC patients. The upregulation of SNX5 in HCC was associated with vascular invasion, intrahepatic metastasis, and poor prognosis. The overexpression of SNX5 promoted HCC cell proliferation, migration, invasion, and metastasis, whereas silencing SNX5 expression resulted in decreased cell proliferation, migration, and invasion. Knockdown of SNX5 significantly inhibited HCC cell proliferation by inducing G1/S transition arrest. Mechanistically, we demonstrated that SNX5 promoted cell proliferation, migration, and invasion via the activation of the EGFR-ERK1/2 pathway by blocking EGF-mediated EGFR internalization. We found that SNX5 interacted with EGFR in HCC cells. Moreover, SNX5-induced cell proliferation, migration, and invasion were partially reversed by the knockdown of EGFR or by ERK1/2 inhibitors. In addition, we demonstrated that SNX5 knockdown sensitized HCC cells to tyrosine kinase inhibitors, including erlotinib and sorafenib. Taken together, our results indicate that SNX5 promotes HCC cell proliferation and metastasis via inhibiting the endocytosis and degradation of EGFR, thereby activating the ERK1/2 signaling pathway. Our work also suggests that SNX5 is a potential therapeutic target for HCC.

TCF12 promotes the tumorigenesis and metastasis of hepatocellular carcinoma via upregulation of CXCR4 expression.

TCF12, which is known to be involved in the regulation of cell growth and differentiation, has been reported to function as an oncogene or a tumor suppressor gene in the progression of various malignant tumors. However, its function and molecular mechanism in hepatocellular carcinoma (HCC) remain unclear. Methods: Stable ectopic TCF12 expression or knockdown in HCC cell lines was established by lentiviral infection. Then, MTT, colony formation, migration, invasion and HUVECs tube formation assays as well as an orthotopic xenograft model were used to investigate the biologic function of TCF12 in HCC cells in vitro and in vivo. Subsequently, RNA-Seq analysis was utilized to explore the target genes regulated by TCF12. RT-qPCR, western blotting, a dual-luciferase reporter assay, Ch-IP, CHIP-Seq and functional rescue experiments were used to confirm the target gene regulated by TCF12. Finally, RT-qPCR, western blot and immunohistochemical (IHC) staining were performed to detect the expression level of TCF12 and to analyze the correlation of TCF12 with downstream genes as well as the clinical significance of TCF12 in human primary HCC. Results: Our functional studies revealed that stable overexpression of TCF12 in human HCC cells enhanced cell proliferation, migration and invasion in vitro and in vivo, whereas knockdown of TCF12 showed opposing effects. Mechanistically, CXCR4 was a downstream target of TCF12, and TCF12 directly bound to the CXCR4 promoter to regulate its expression. Moreover, CXCR4, with its ligand CXCL12, played a critical role in tumor progression induced by TCF12 via activation of the MAPK/ERK and PI3K/AKT signaling pathways. Clinically, IHC analysis revealed that TCF12 was significantly associated with poor survival of HCC patients and that TCF12 expression was closely correlated with CXCR4 expression in primary HCC tissues. Conclusion: Our findings are the first to indicate that TCF12 could promote the tumorigenesis and progression of HCC mainly by upregulating CXCR4 expression and is a prognostic indicator for patients with HCC.

HIF-1α-induced RIT1 promotes liver cancer growth and metastasis and its deficiency increases sensitivity to sorafenib.

Ras-like-without-CAAX-1 (RIT1) belongs to the RAS superfamily of small GTPases, which plays critical roles in tumor progression. However, little is known about the roles of RIT1 in hepatocellular carcinoma (HCC). Here we found that RIT1 expression was positively associated with the presence of intrahepatic metastasis and the histological grade of HCC and higher RIT1 expression indicated shorter overall survival in HCC patients. In vitro and in vivo studies revealed that RIT1 functioned as an oncogene, as overexpression of RIT1 enhanced HCC cell proliferation and aggressive behavior, whereas silencing RIT1 expression repressed the malignant behaviors. Furthermore, RIT1 deficiency increased drug sensitivity to sorafenib treatment. We further demonstrated that hypoxia-inducible factor 1α (HIF-1α) directly transcriptionally upregulated RIT1, and its stableness was positively correlated with RIT1 expression in HCC tissues. Knockdown of RIT1 attenuated the invasion and migration induced by hypoxia. Collectively, our data highlight the significance of HIF-1α/RIT1 axis in driving HCC progression and sorafenib resistance.

Characterization of rare NEIL1 variants found in East Asian populations.

The combination of chronic dietary exposure to the fungal toxin, aflatoxin B1 (AFB1), and hepatitis B viral (HBV) infection is associated with an increased risk for early onset hepatocellular carcinomas (HCCs). An in-depth knowledge of the mechanisms driving carcinogenesis is critical for the identification of genetic risk factors affecting the susceptibility of individuals who are HBV infected and AFB1 exposed. AFB1-induced mutagenesis is characterized by G to T transversions. Hence, the DNA repair pathways that function on AFB1-induced DNA adducts or base damage from HBV-induced inflammation are anticipated to have a strong role in limiting carcinogenesis. These pathways define the mutagenic burden in the target tissues and ultimately limit cellular progression to cancer. Murine data have demonstrated that NEIL1 in the DNA base excision repair pathway was significantly more important than nucleotide excision repair relative to elevated risk for induction of HCCs. These data suggest that deficiencies in NEIL1 could contribute to the initiation of HCCs in humans. To investigate this hypothesis, publicly-available data on variant alleles of NEIL1 were analyzed and compared with genome sequencing data from HCC tissues derived from individuals residing in Qidong County (China). Three variant alleles were identified and the corresponding A51V, P68H, and G245R enzymes were characterized for glycosylase activity on genomic DNA containing a spectrum of oxidatively-induced base damage and an oligodeoxynucleotide containing a site-specific AFB1-formamidopyrimidine guanine adduct. Although the efficiency of the P68H variant was modestly decreased, the A51V and G245R variants showed nearly wild-type activities. Consistent with biochemical findings, molecular modeling of these variants demonstrated only slight local structural alterations. However, A51V was highly temperature sensitive suggesting that its biological activity would be greatly reduced. Overall, these studies have direct human health relevance pertaining to genetic risk factors and biochemical pathways previously not recognized as germane to induction of HCCs.