Evasion of ferroptosis has been increasingly recognized as an important mechanism underlying lenvatinib resistance in hepatocellular carcinoma (HCC). However, the roles of deubiquitinating enzymes in ferroptosis regulation and the post-translational control of key ferroptosis regulators in HCC remain poorly understood. Public lenvatinib resistance-related and ferroptosis-related datasets were analyzed to identify candidate deubiquitinating enzymes associated with HCC therapeutic resistance and ferroptotic stress. Loss- and gain-of-function assays were performed to evaluate the effects of OTUD1 on lenvatinib sensitivity, erastin-induced ferroptosis, and HCC cell growth. Subcutaneous xenograft and orthotopic tumor models were used to assess the role of OTUD1 in tumor growth and ferroptosis resistance in vivo. Western blotting, RT-qPCR, co-immunoprecipitation, cycloheximide chase, MG132 rescue, ubiquitination, SLC7A11 rescue, and ERK1/2 pathway modulation assays were conducted to investigate the underlying mechanism. Clinical HCC specimens and public datasets were analyzed to determine OTUD1 expression and its association with patient prognosis. OTUD1 was identified as a gene associated with lenvatinib resistance in HCC. Knockdown of OTUD1 sensitized HCC cells to lenvatinib, and this effect was abolished by ferroptosis inhibition. OTUD1 knockdown enhanced ferroptosis in HCC cells, whereas OTUD1 overexpression suppressed it. Moreover, OTUD1 promoted HCC growth and conferred ferroptosis resistance in mice. Mechanistically, OTUD1 interacted with solute carrier family 7 member 11 (SLC7A11) and removed its K48-linked polyubiquitin chains, thereby stabilizing SLC7A11 protein levels. In addition, ERK1/2-dependent phosphorylation of OTUD1 at Ser216 strengthened its interaction with SLC7A11, further enhancing SLC7A11 stability and promoting ferroptosis resistance. Analysis of clinical samples and public datasets further revealed that OTUD1 was upregulated in HCC tissues and correlated with poor prognosis. Our findings identify the ERK1/2–OTUD1–SLC7A11 axis as a key mechanism mediating ferroptosis resistance in HCC. These results suggest that OTUD1 may serve as a potential therapeutic target for HCC.

Following the publication of the above paper, it was drawn to the Editor's attention by a concerned reader that certain of the flow cytometric data shown in Fig. 3C, the immunohistochemical data shown in Fig. 4B and the western blots in Fig. 5B had already been submitted to, or were published in, articles in other journals that featured some of the same authors; moreover, some of these data subsequently appeared in different articles in other journals that were not connected with either this research group or this research topic. Upon investigating these issues further in the Editorial Office, it was noted that, concerning Figs. 3‑5 and as far as those papers sharing some of the same authors was concerned, the cases of data sharing weren't necessarily as simple as the data merely being duplicated. Given the sharing of these contentious data across a number of different journals, the Editor of Oncology Reports has decided that this paper should be retracted from the Journal on account of a lack of confidence in the presented data. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a reply. The Editor apologizes to the readership for any inconvenience caused. [Oncology Reports 32: 1571‑1577, 2024; DOI: 10.3892/or.2014.3386].

Treatment options for hepatocellular carcinoma (HCC) remain limited, and patient prognosis is generally poor. Therefore, elucidating the molecular mechanisms underlying HCC initiation and progression is critical for identifying novel therapeutic targets. Our previous study demonstrated that BICD cargo adaptor 1 (BICD1) was upregulated in HCC and functioned as a tumor promoter. However, the upstream regulators of BICD1 expression and the molecular basis of its pro-tumorigenic effects remain unclear. In this study, we identified Yes-associated protein (YAP) as a positive regulator of BICD1 in HCC. Mechanistically, YAP directly bound to the BICD1 promoter and enhanced its transcriptional activity. BICD1 expression was positively correlated with YAP, connective tissue growth factor (CTGF), and cysteine-rich angiogenic inducer 61 (CYR61) in HCC tissues. Functionally, BICD1 knockdown significantly attenuated hypoxia-induced proliferation, sphere formation, and migration of HCC cells, whereas BICD1 overexpression enhanced these phenotypes. In addition, BICD1 depletion markedly suppressed tumor initiation and growth in a nude mouse model. Further mechanistic investigations revealed that BICD1 interacted with hypoxia-inducible factor-1α (HIF-1α) via its C-terminal CC3 domain, thereby promoting HIF-1α nuclear translocation and transcriptional activity in HCC cells. Notably, AKT activation or knockdown of glycogen synthase kinase 3β (GSK3β) significantly enhanced the interaction between BICD1 and HIF-1α, thereby increasing HIF-1α transcriptional activity. Collectively, these findings demonstrate that YAP-driven BICD1 expression facilitates HIF-1α nuclear translocation and activation of downstream target genes, thereby promoting hypoxia-induced proliferation, stemness, and migration in HCC. This study highlights the YAP-BICD1-HIF-1α axis as a potential therapeutic target in HCC.

Hepatocellular carcinoma (HCC) is an exceedingly aggressive form of cancer that often carries a poor prognosis, especially when it is complicated by the presence of microvascular invasion (MVI). Identifying patients at high risk of MVI is crucial for personalized treatment strategies. Utilizing the single-cell RNA-sequencing dataset (GSE242889) of HCC, we identified malignant cell subtypes associated with microvascular invasion (MVI), in conjunction with the TCGA dataset, selected a set of MVI-related genes (MRGs). We developed an optimal prognostic model comprising 11 genes (NOP16, YIPF1, HMMR, NDC80, DYNLL1, CDC34, NLN, KHDRBS3, MED8, SLC35G2, RAB3B) based on MVI-related signature genes by integrating single-cell transcriptomic analysis with 101 machine learning algorithms. This model is meticulously crafted to forecast the prognosis of individuals afflicted with hepatocellular carcinoma (HCC). Additionally, we affirmed the predictive precision and superiority of our model through a meta-analysis against existing HCC models. Furthermore, we explored the differences between high- and low-risk groups through mutation and immune infiltration analyses. Lastly, we investigated immunotherapy responses and drug sensitivities between risk groups, providing novel therapeutic insights for liver cancer.

Background Hepatocellular carcinoma (HCC) is one of the most common and challenging cancers in the world. N6-methyladenosine (m 6 A) modification and long non-coding RNAs (lncRNAs) play critical roles in the progression of HCC. However, there are few reports on genome-wide screening and functional annotations of m 6 A-methylated lncRNAs in HCC. Methods The expression levels of m 6 A methyltransferase METTL3 and the association with the prognosis in HCC were determined by RT-qPCR, public dataset platforms. Then, RNA-seq, Pearson correlation analysis, MeRIP-qPCR, RNA half-life assay, gene site-directed mutation, RIP assay and RT-qPCR analysis were employed to determine the downstream target of METTL3 in HCC. Subsequently, the expression levels and roles of lncRNA glucosylceramidase beta pseudogene 1 (GBAP1) in HCC were determined by Kaplan–meier curves, RT-qPCR, in vitro functional experiments and in vivo tumorigenesis and lung metastasis models. Then, the downstream target and pathway of GBAP1 were explored by GO biological process, KEGG pathway enrichment, luciferase reporter assay, RIP assay and rescue experiments and so on. Results METTL3 was upregulated in HCC and closely related to HCC prognosis. And METTL3 induced GBAP1 expression by acting as the m 6 A writer of GBAP1 and IGF2BP2 worked as its m 6 A reader. Clinically, GBAP1 expression was significantly associated with tumor size, venous infiltration, TNM stage and prognosis of HCC, Functionally, GBAP1 promoted HCC metastasis and growth both in vitro and in vivo. Furthermore, GBAP1 acted as the molecular sponge for miR-22-3p to increase the expression of bone morphogenetic protein receptor type 1A (BMPR1A), which then activated BMP/SMAD pathway in HCC cells. Conclusions Our findings demonstrated that METTL3-induced GBAP1 promoted migration, invasion and proliferation of HCC cells via GBAP1/miR-22-3p/BMPR1A/SMAD axis. GBAP1 could be a potential prognosis indicator and therapeutic target for HCC.

Aberrant expression of microRNAs (miRNAs) and its dysfunction have been revealed as crucial modulators of cancer initiation and progression. MiR-129-2 has been reported to play a tumor suppressive role in different human malignancies. Here, we demonstrated that miR-129-2 was significantly decreased in hepatocellular carcinoma (HCC) tissues and cell lines. Furthermore, miR-129-2 was expressed at significant lower levels in aggressive and recurrent tumor tissues. Clinical analysis indicated that miR-129-2 expression was inversely correlated with venous infiltration, high Edmondson-Steiner grading and advanced tumor-node-metastasis (TNM) stage in HCC. Notably, miR-129-2 was an independent prognostic factor for indicating overall survival (OS) and disease-free survival (DFS) of HCC patients. Ectopic expression of miR-129-2 inhibited cell migration and invasion in vitro and in vivo. Furthermore, we confirmed that high mobility group box 1 (HMGB1) was a direct target of miR-129-2, and it abrogated the function of miR-129-2 in HCC. Mechanistic investigations showed that miR-129-2 overexpression inhibited AKT phosphorylation at Ser473 and decreased the expression of matrix metalloproteinase2/9 (MMP2/9). Upregulation of p-AKT abolished the decreased cell migration and invasion induced by miR-129-2 in HCC. Whereas inhibition of Akt phosphorylation significantly decreased HMGB1-enhanced HCC cell migration and invasion. Moreover, we found that miR-129-2 was downregulated by DNA methylation, and demethylation of miR-129-2 increased miR-129-2 expression in HCC cells and resulted in significant inhibitory effects on cell migration and invasion. In conclusion, miR-129-2 may serve as a prognostic indicator for HCC patients and exerts tumor suppressive role, at least in part, by inhibiting HMGB1.

Although FKBP prolyl isomerase 4 (FKBP4) is upregulated in WHV/c-myc mouse livers and hepatocellular carcinoma (HCC) tissues, its clinical significance, role in tumor progression, and the underlying mechanism of involvement in HCC remain unclear. In this study, data from public databases and our HCC cohort showed upregulated FKBP4 expression in tumor tissues. Increased FKBP4 levels was associated with malignant clinical features of HCC, including tumor diameter ≥ 3 cm, poor differentiation, and advanced tumor stage. Cox regression analysis recognized FKBP4 as one of the independent risk factors for poor overall survival of patients with HCC. The proliferation, migration, and invasion of SNU449 and Huh7 cells were significantly reduced by FKBP4 knockdown, but enhanced by FKBP4 overexpression. C-Myc positively regulated FKBP4 expression in HCC cells. Mechanistically, c-Myc directly binds to the FKBP4 promoter and activates gene transcription. The interaction of FKBP4 with PH domain and leucine rich repeat protein phosphatase 1 (PHLPP1) enhanced its ubiquitination and degradation, subsequently activating the protein kinase B (AKT) pathway. AKT inhibition (with MK-2206) and PHLPP1 overexpression prominently attenuated the FKBP4-induced increase in HCC cell proliferation and invasion. FKBP4 knockdown suppressed the growth of SNU449 cells in vivo. PHLPP1 overexpression markedly abolished FKBP4-enhanced HCC growth in mice. In conclusion, FKBP4 overexpression was correlated with poor prognosis in patients with HCC. C-Myc transcriptionally activated-FKBP4 interacted with PHLPP1 to enhance its ubiquitin-mediated degradation, thereby enhancing the AKT pathway and facilitating HCC cell proliferation and invasion. Our findings provide a theoretical basis for targeting FKBP4 in treating HCC.

Hepatocellular carcinoma (HCC) is one of the most common cancers, and diabetes is a risk factor for hepatocarcinogenesis. N6-methyladenosine (m6A) methyltransferase WT1-associated protein (WTAP) is highly expressed in HCC and contributes to tumor progression. However, its role in high glucose-driven HCC progression remains unclear. The m6A quantitative assay was used to detect the m6A modification level. The levels of mRNAs and proteins were detected by qPCR, Western blot, and immunohistochemistry. CCK-8, colony formation, EdU, and transwell assays were used to detect HCC cell proliferation, invasion, and migration. Immunoprecipitation and CHX assays were used to reveal the regulatory effect of high glucose on WTAP. An RNA degradation experiment was used to explore WTAP's regulation of HK2 mRNA. To demonstrate the effect of high glucose on HCC growth in vivo, a diabetic mouse model was constructed, and HCC cells were subcutaneously injected. High glucose prominently increased the global level of m6A in HCC cells. Interestingly, high glucose upregulated WTAP protein rather than mRNA expression. We found that WTAP expression was significantly upregulated in HCC tissues, especially in tumor tissues of diabetic patients. WTAP knockdown markedly attenuated high glucose-induced abilities of HCC cell proliferation, colony formation, migration, and invasion. Meanwhile, WTAP overexpression significantly enhanced the malignant behaviors of HCC cells under low glucose conditions. High glucose reduced the ubiquitination of WTAP, thereby inhibiting its proteasomal and lysosomal degradation. Phosphorylated ERK (p-ERK) was required for high glucose-mediated WTAP stability. WTAP knockdown prominently abrogated high glucose-induced global m6A levels and HK2 expression in HCC cells. WTAP positively regulated HK2 expression by increasing mRNA stability. HK2 overexpression remarkably reversed the suppressive effects of WTAP knockdown on HCC cells. HK2 knockdown prominently abolished the promoting role of WTAP in HCC cells. Importantly, the growth of HCC cells in diabetic mice was significantly faster than that in control mice, which was prominently attenuated by WTAP knockdown. Our study demonstrated that high glucose decreased WTAP degradation and maintained its protein level by activating ERK phosphorylation. WTAP promoted HCC cell proliferation, colony formation, migration, and invasion by stabilizing HK2 mRNA.

Hepatocellular carcinoma (HCC) is the third cause of cancer-related death worldwide. Accumulating studies have demonstrated that aberrant expression of several lncRNAs was found to be involved in the hepatocarcinogenesis. In this study, a lncRNA Ftx was chosen to investigate its effects on HCC cells, and clarify the possible mechanism. We demonstrated that the lncRNA Ftx and Ftx-derived miR-545 were up-regulated in both HCC tissues and cells. MiR-545 was positively correlated with lncRNA Ftx expression. Notably, clinical association analysis revealed that the high expression of lncRNA Ftx and miR-545 was associated with poor prognostic features, and conferred a reduced 5-year overall survival (OS) and disease-free survival (DFS) of HCC patients. We found that miR-545 was a pivotal mediator in Ftx-induced promotion of HCC cell growth. Subsequently, we identified RIG-I as a direct target of miR-545. The expression of RIG-I was downregulated in HCC tissues and was inversely correlated with miR-545 expression. Our data revealed that ectopic expression of RIG-I abrogated the effects of lncRNA Ftx or miR-545 on HCC cells. LncRNA Ftx/miR-545-mediated downregulation of RIG-I led to increased Akt phosphorylation in vitro and in vivo. Inhibition of Akt phosphorylation abolished the effects of lncRNA Ftx/miR-545 on HCC cells. In conclusion, our study demonstrates that the novel pathway lncRNA Ftx/miR-545/RIG-I promotes HCC development by activating PI3K/Akt signaling, and it may serve as a novel prognostic biomarker and therapeutic target for HCC.

BACKGROUND:Fibulin-5 has been considered as a tumor suppressor through inhibiting tumor growth and invasion. Reduced expression of Fibulin-5 is frequently observed in various human cancers. In this study, we investigate the clinical significance of Fibulin-5 and its role in hepatocellular carcinoma (HCC) cell migration and invasion. METHODS:The expression of Fibulin-5 was evaluated by qRT-PCR and immunoblotting in HCC and matched noncancerous tissues. Fibulin-5 was over-expressed or knocked down by a retrovirus-mediated expression plasmid or a specific siRNA in HCC cells. Boyden chamber and Transwell assays were used to test HCC cell migration and invasion. Immunostaining was performed to determine matrix metalloproteinase-7 (MMP-7) expression in HCC specimens. MMP-7 retroviruses and siRNA were used to alter MMP-7 expression in HCC cells. RESULTS:In our study, the expression levels of Fibulin-5 protein and mRNA were down-regulated in HCC tissues as compared with those in matched noncancerous tissues. Reduced expression of Fibulin-5 was observed in all HCC cell lines (HepG2, SMMC-7721, MHCC97L, Hep3B, MHCC97H and HCC-LM3) as compare with that in a non-transformed hepatic cell line (LO2). Low expression of Fibulin-5 was significantly correlated with poor prognostic features including multiple tumor nodes, venous infiltration, high Edmondson-Steiner grading and advanced tumor-node-metastasis (TNM) tumor stage. Furthermore, we demonstrated that Fibulin-5 was a novel independent prognostic marker for predicting 5-year survival of HCC patients. Our in vitro studies showed that Fibulin-5 overexpression inhibited HCC cell migration and invasion. While Fibulin-5 knockdown increased the number of migrated and invaded HCC cells. Fibulin-5 negatively regulated MMP-7 abundance in HCC cells. Moreover, the inverse correlation between Fibulin-5 and MMP-7 expressions was observed in HCC tissues. Mechanistically, we disclosed that MMP-7 knockdown reduced the number of migrated and invaded HCC cells. Restoring MMP-7 expression abrogated the suppressive effect of Fibulin-5 on HCC cell migration and invasion in vitro, suggesting that Fibulin-5 exerted its anti-metastatic function, at least in part, by down-regulating the expression of MMP-7 in HCC cells. CONCLUSIONS:These results indicate that Fibulin-5 may serve as a prognostic biomarker and inhibits HCC invasion and metastasis by suppressing MMP-7 expression.

BackgroundMatrix stiffness is strongly associated with hepatocarcinogenesis and significantly influences the properties of hepatocellular carcinoma (HCC). Investigating matrix stiffness-related signatures provides crucial insights into HCC prognosis and therapeutic response.MethodsMulti-omics data from liver hepatocellular carcinoma (LIHC) were integrated using 10 clustering algorithms, identifying three subgroups with distinct survival outcomes and treatment responses. A matrix stiffness-related signature comprising 57 genes was constructed by evaluating 101 machine learning algorithm combinations. PPARG, the key gene with the greatest contribution to the model, was selected for validation. Single-cell RNA sequencing (scRNA-seq) and spatial transcriptomics (ST) analyses assessed matrix stiffness activity scores across different cell subgroups and examined PPARG spatial localization within tissues. Experimental studies and bioinformatics analyses further explored the role of PPARG in HCC carcinogenesis and the immune microenvironment.ResultsThe matrix stiffness-related signature demonstrated superior prognostic prediction performance in both training and validation cohorts compared to other existing HCC signatures. Distinct immune and mutation landscape characteristics were observed between patients categorized into high and low matrix stiffness groups. PPARG functioned in tumorigenesis through HSC activation and immune suppression. Furthermore, increased matrix stiffness was found to upregulate PPARG expression, promoting cell proliferation, activating lipid metabolism, and enhancing the stemness of HCC cells through the MAPK signaling pathway. Targeting PPARG with trametinib displayed an enhanced therapy response.ConclusionsThe matrix stiffness-related signature not only serves as a robust prognostic tool but also aids in identifying immune characteristics and optimizing therapeutic strategies, thus advancing personalized medicine for patients with HCC.

Background Autoimmune liver diseases (AILDs) encompass autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), and primary sclerosing cholangitis (PSC). The onset of these diseases is fundamentally influenced by genetic susceptibility. Although various extrahepatic factors are potentially linked to AILDs, the genetic underpinnings and mechanisms of these associations remain unclear. Methods Utilizing large-scale genome-wide association study (GWAS) data, this study systematically investigated the relationships between extrahepatic autoimmune diseases (EHAIDs), immune cells, and various triggering factors with AILDs. Mendelian randomization (MR) was employed to assess the causal effects of these extrahepatic factors on AILDs, complemented by linkage disequilibrium score (LDSC) regression to uncover shared genetic architecture and causal effects underlying the associations between autoimmune diseases. We employed colocalization, enrichment analysis, and protein-protein interaction (PPI) network to identify the functions of shared loci. Additionally, we proposed that activated immune cells in the circulation may contribute to liver and biliary tract inflammation via migration, mediating the impact of extrahepatic factors on AILDs. This hypothesis was tested using two mediation analysis methods: two-step MR (TSMR) and multivariable MR (MVMR). Results Causal associations between multiple extrahepatic factors and AILDs were identified. Notably, CD27+ B cells were found to be a risk factor for PBC, while PSC progression was associated with CD28+ CD8+ T cells exhaustion and increased levels of CD28- CD8+ T cells. Mediation analyses revealed 64 pathways via TSMR and 15 pathways via MVMR, indicating that the effects of extrahepatic factors on AILDs may be mediated by circulating immune cells. The shared genetic architecture also contributed to these associations. Analysis of shared loci and gene functions identified ATXN2 as being shared between PBC and 9 EHAIDs, while SH2B3 and PSMG1 were shared with 6 and 5 EHAIDs, respectively, in PSC. Conclusions Our research compared three distinct AILDs, enhancing the understanding of their etiology and providing new evidence on risk factors, diagnostic markers, and potential therapeutic targets.

The occurrence of cancer is often accompanied by immune evasion and tumor-promoting inflammation, with interleukins (IL) playing a pivotal role in the immune-inflammatory mechanism. However, the precise contribution of serum interleukins in cancer remains elusive. We obtained GWAS summary data for 35 interleukins from eight independent large-scale serum proteome studies of European ancestry populations and for 23 common cancers from the FinnGen Consortium. We then conducted a multicenter Mendelian Randomization (MR) study to explore the relationship between systemic inflammatory status and cancers. 24 causal associations between interleukins and cancers were supported by multicenter data, 18 of which were reported for the first time. Our results indicated that IL-1α (Hodgkin lymphoma), IL-5 (bladder cancer), IL-7 (prostate cancer), IL-11 (bone malignant tumor), IL-16 (lung cancer), IL-17A (pancreatic cancer), IL-20 (bladder cancer), IL-22 (lymphocytic leukemia), IL-34 (breast cancer), IL-36β (prostate cancer), and IL-36γ (liver cancer) were risk factors for related cancers. Conversely, IL-9 (malignant neoplasms of the corpus uteri), IL-17C (liver cancer), and IL-31 (colorectal cancer, bladder cancer, pancreatic cancer, and cutaneous melanoma) exhibited protective effects against related cancers. Notably, the dual effects of serum interleukins were also observed. IL-18 acted as a risk factor for prostate cancer, however, was a protective factor against laryngeal cancer. Similarly, IL-19 promoted the development of lung cancer and myeloid leukemia, while conferring protection against Breast, cervical, and thyroid cancers. Our study confirmed the genetic association between multiple serum interleukins and cancers. Immune and anti-inflammatory strategies targeting these associations provide opportunities for prevention and treatment.

Hypoxic microenvironment plays a critical role in solid tumor growth, metastasis and angiogenesis. Hypoxia-inducible factors (HIFs), which are canonical transcription factors in response to hypoxia, are stabilized under hypoxia and they coordinate the process of hypoxia-induced gene expression leading to cancer progression. Increasing evidence has indicated that long noncoding RNAs (lncRNAs) which are closely associated with cancer play crucial roles in hypoxia-mediated HCC progression, while the mechanisms are largely unknown. Here, we identified a novel lncRNA SZT2-AS1 in HCC, which was induced by hypoxia in a HIF-1-dependent manner and promoted HCC growth, metastasis and angiogenesis. The clinical data indicated that SZT2-AS1 level was substantially upregulated in HCC and significantly associated with poor clinical outcomes, and acted as an independent prognostic predictor. Mechanistically, SZT2-AS1, in turn, recruited HIF-1α and HIF-1β to form the HIF-1 heterodimer. And SZT2-AS1 was required for the occupancy of HIF-1 to hypoxia response elements (HREs) and HIF target gene transcription. In addition, SZT2-AS1 was required for hypoxia-induced histone trimethylation (H3K4me3 and H3K36me3) at HREs. Through recruiting methyltransferase SMYD2, SZT2-AS1 promoted trimethylation modification of H3K4 and H3K36 in HCC cells. Taken together, our results uncovered a lncRNA-involved positive feedback mechanism under hypoxia and established the clinical value of SZT2-AS1 in prognosis and potential therapeutic strategy for HCC. Significance: LncRNA SZT2-AS1 involves in a positive feedback mechanism under hypoxia, which provides a therapeutic strategy for HCC.

Hypoxic microenvironment plays a critical role in solid tumor growth, metastasis and angiogenesis. Hypoxia-inducible factors (HIFs), which are canonical transcription factors in response to hypoxia, are stabilized under hypoxia and coordinate the process of hypoxia-induced gene expression, leading to cancer progression. Increasing evidence has uncovered that long noncoding RNAs (lncRNAs), which are closely associated with cancer, play crucial roles in hypoxia-mediated HCC progression, while the mechanisms are largely unknown. Here, we identified SZT2-AS1 as a novel lncRNA in HCC, which was induced by hypoxia in a HIF-1-dependent manner and promoted HCC growth, metastasis and angiogenesis both in vitro and in vivo. And SZT2-AS1 also mediated the hypoxia-induced HCC progression. Clinical data indicated that SZT2-AS1 level was substantially increased in HCC and closely associated with poor clinical outcomes, acting as an independent prognostic predictor. Mechanistically, SZT2-AS1 recruited HIF-1α and HIF-1β to form the HIF-1 heterodimer, and it was required for the occupancy of HIF-1 to hypoxia response elements (HREs) and HIF target gene transcription. In addition, SZT2-AS1 was required for hypoxia-induced histone trimethylation (H3K4me3 and H3K36me3) at HREs. Through recruiting methyltransferase SMYD2, SZT2-AS1 promoted trimethylation of H3K4 and H3K36 in HCC cells. Taken together, our results uncovered a lncRNA-involved positive feedback mechanism under hypoxia and established the clinical value of SZT2-AS1 in prognosis and as a potential therapeutic target in HCC.

BackgroundTo predict the early recurrence of HCC patients who received radical resection using preoperative variables based on Gd-EOB-DTPA enhanced MRI, followed by the comparison with the postoperative model and clinical staging systems.MethodsOne hundred and twenty-nine HCC patients who received radical resection were categorized into the early recurrence group (n=48) and the early recurrence-free group (n=81). Through COX regression analysis, statistically significant variables of laboratory, pathologic, and Gd-EOB-DTPA enhanced MRI results were identified. The preoperative and postoperative models were established to predict early recurrence, and the prognostic performances and differences were compared between the two models and clinical staging systems.ResultsSix variables were incorporated into the preoperative model, including alpha-fetoprotein (AFP) level, aspartate aminotransferase/platelet ratio index (APRI), rim arterial phase hyperenhancement (rim APHE), peritumoral hypointensity on hepatobiliary phase (HBP), CERHBP (tumor-to-liver SI ratio on hepatobiliary phase imaging), and ADC value. Moreover, the postoperative model was developed by adding microvascular invasion (MVI) and histological grade. The C-index of the preoperative model and postoperative model were 0.889 and 0.901 (p=0.211) respectively. Using receiver operating characteristic curve analysis (ROC) and decision curve analysis (DCA), it was determined that the innovative models we developed had superior predictive capabilities for early recurrence in comparison to current clinical staging systems. HCC patients who received radical resection were stratified into low-, medium-, and high-risk groups on the basis of the preoperative and postoperative models.ConclusionThe preoperative and postoperative MRI-based models built in this study were more competent compared with clinical staging systems to predict the early recurrence in hepatocellular carcinoma.

Zinc finger protein 131 (ZNF131), a member of BTB-ZF transcription factors, has been previously reported as an oncogene in several human cancers. However, the function and underlying mechanism of ZNF131 in hepatocellular carcinoma (HCC) are still unclear. In our study, the upregulated expression of ZNF131 mRNA was confirmed in HCC tissues by analyzing the TCGA and GEO datasets. The immunohistochemical staining data also revealed the overexpression of ZNF131 protein in HCC samples. High expression of ZNF131 predicted poor overall survival and disease-free survival in HCC patients. ZNF131 knockdown inhibited the proliferation and colony formation and led to G2/M phase arrest of HCC cells, while its overexpression promoted HCC cell proliferation, cell cycle progression and colony formation. Moreover, ZNF131 silencing repressed the growth of HCC cells in nude mice. Yes-associated protein 1 (YAP1) was recognized as an upstream regulator of ZNF131. Both YAP1 knockdown and inactivation reduced ZNF131 expression in HCC cells, and YAP1 overexpression enhanced ZNF131 level. Interestingly, we found that poly(A) binding protein interacting protein 1 (PAIP1) was a novel target of ZNF131. ZNF131 silencing downregulated while ZNF131 overexpression upregulated PAIP1 expression in HCC cells. The luciferase reporter assay demonstrated that ZNF131 regulated PAIP1 expression at the transcription level. Notably, we revealed that ZNF131 activated the AKT signaling by enhancing PAIP1 expression in HCC cells. AKT inhibitor markedly attenuated ZNF131-enhanced HCC cell proliferation. Restoring PAIP1 expression abrogated the inhibitory effects of ZNF131 knockdown on HCC cell proliferation and colony formation. To conclude, ZNF131 was highly expressed and acted as an oncogene in HCC. ZNF131, which was activated by YAP1, promoted HCC cell proliferation through transcriptional regulation of PAIP1.

BACKGROUND:The occurrence and progression of hepatocellular carcinoma (HCC) are significantly affected by DNA damage response (DDR). Exploring DDR-related biomarkers can help predict the prognosis and immune characteristics of HCC. METHODS:First, the single-cell RNA sequencing (scRNA-seq) dataset GSE242889 was processed and performed manual annotation. Then we found the marker genes of DDR-active subgroups based on "AUCell" algorithm. The "Limma" R package was used to identify differentially expressed genes (DEGs) between tumor and normal samples of HCC. The risk prognostic model was constructed by filtering genes using univariate Cox and LASSO regression analyses. Finally, the signatures were analyzed for immune infiltration, gene mutation, and drug sensitivity. Last but not least, KPNA2, which had the largest coefficient in our model was validated by experiments including western blot, MTT, colony formation and γ-H2AX assays. RESULTS:We constructed a prognostic model based on 5 DDR marker genes including KIF2C, CDC20, KPNA2, UBE2S and ADH1B for HCC. We also proved that the model had an excellent performance in both training and validation cohorts. Patients in the high-risk group had a poorer prognosis, different immune features, gene mutation frequency, immunotherapy response and drug sensitivity compared with the low-risk group. Besides, our experimental results proved that KPNA2 was up-regulated in liver cancer cells than in hepatocytes. More importantly, the knockdown of KPNA2 significantly inhibited cell variability, proliferation and promoted DNA damage. CONCLUSIONS:We innovatively integrated scRNA-seq and bulk RNA sequencing to construct the DDR-related prognostic model. Our model could effectively predict the prognosis, immune landscape and therapy response of HCC.

[This corrects the article DOI: 10.7150/thno.26789.].

Matrix stiffness is a central modulator of hepatic stellate cells (HSCs) activation and hepatic fibrogenesis. However, the long non-coding RNAs (lncRNAs)-regulated transcriptional factors linking matrix stiffness to alterations in HSCs phenotype are not completely understood. In this study, we investigated the effects of matrix stiffness on HSCs activation and its potential mechanism. Through analysis the RNA-seq data with human primary HSCs cultured on 0.4 kPa and 25.6 kPa hydrogel, we identified that forkhead box protein C2 (FOXC2) and its antisense lncRNA FXOC2-AS1 as the new mechanosensing transcriptional regulators that coordinate HSCs responses to the matrix stiffness, moreover, FOXC2 and FOXC2-AS1 expression were also elevated in human fibrosis and cirrhosis tissues. The matrix stiffness was sufficient to activate HSCs into myofibroblasts, resulting in nuclear accumulation of FOXC2. Disrupting FOXC2 and FOXC2-AS1 level abrogated stiffness-induced activation of HSCs. Further mechanistic studies displayed that stiffness-upregulated lncRNA FOXC2-AS1 had no influence on transcription of FOXC2. FOXC2-AS1 exerted its biological function through maintaining the RNA stability of FOXC2, and protecting FOXC2 mRNA from degradation by RNA exosome complex. Additionally, rescue assays confirmed that reintroduction of FOXC2 in FOXC2-AS1-depleted HSCs reversed the repression of FOXC2-AS1 knockdown on stiffness-induced HSCs activation. In AAV6-treated mice fibrotic models, targeting FOXC2 in vivo lead to a reduced degree of liver fibrosis. In sum, our study uncovers a reciprocal crosstalk between matrix stiffness and FOXC2-AS1/FOXC2 axis leading to modulation of HSCs mechanoactivation and liver fibrosis, and present AAV6 shRNA as an effective strategy that targets FOXC2 leading to the resolution of liver fibrosis.