CEP192 is a novel prognostic marker and correlates with the immune microenvironment in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) responds poorly to standard chemotherapy or targeted therapy; hence, exploration for novel therapeutic targets is urgently needed. CEP192 protein is indispensable for centrosome amplification, which has been extensively characterized in both hematological malignancies and solid tumors. Here, we combined bioinformatics and experimental approaches to assess the potential of CEP192 as a prognostic and therapeutic target in HCC. CEP192 expression increased with tumor stage and was associated with poor clinicopathologic features, frequent recurrence, and higher mortality. Upon single-cell RNA sequencing, CEP192 was found to be involved in the proliferation and self-renewal of hepatic progenitor-like cells. This observation was further evidenced using CEP192 silencing, which prevented tumor cell proliferation and self-renewal by arresting cells in the G0/G1 phase of the cell cycle. Notably, CEP192 was highly correlated with multiple tumor-associated cytokine ligand-receptor axes, including IL11-IL11RA, IL6-IL6R, and IL13-IL13RA1, which could promote interactions between hepatic progenitor-like cells, PLVAP+ endothelial cells, tumor-associated macrophages, and CD4+ T cells. Consequently, CEP192 expression was closely associated with an immunosuppressive tumor microenvironment and low immunophenoscores, making it a potential predictor of response to immune checkpoint inhibitors. Taken together, our results unravel a novel onco-immunological role of CEP192 in establishing the immunosuppressive tumor microenvironment and provide a novel biomarker, as well as a potential target for therapeutic intervention of HCC.

Enhanced functional properties of human limbal stem cells by inhibition of the miR-31/FIH-1/P21 axis.

OBJECTIVE: On the basis of the functional roles of the embryonic stem cell niche (ESCN) in the human limbal stem cells (LSCs), we proposed to explore the potential roles of microRNAs in regulating the self-renewal and differentiation of LSCs cultured in the ESCN. METHODS: The LSCs were cultured in different media, either in CnT-20 media or in CnT-20 + 20% ES culture supernatant (ESC-CM). The LSCs cultured in ESC-CM were then transfected with microRNA-31 (miR-31) mimic or antago-31. The colony-forming efficiency (CFE) was analysed. Cell cycle, apoptosis, mitochondrial potential and reactive oxygen species were analysed by flow cytometry, and quantitative real-time PCR was used to determine the expression levels of FIH-1, P21, P63, ABCG2, CK3, microRNA-31, microRNA-143, microRNA-145 and microRNA-184. Indirect immunostaining was employed to detect the expression of P63, ABCG2, survivin, connexin-43 and CK3. Western blot was employed to detect the expression of FIH-1, P63, P21, CK3, caspase 3, Tcf4, ß-catenin, survivin, GSK3ß and pGSK3ß. RESULTS: Compared with cells grown in CnT-20, the level of miR-31 in cells grown in ESC-CM was lower. We investigated the roles that miR-31 and FIH-1 play in regulating the functional properties of LSCs. We used antagomirs (antago) to reduce the level of miR-31 in LSCs. Antago-31 increased FIH-1 levels and significantly reduced P21 expressional level in LSCs compared to irrelevant-antago (Ir-antago) treatment. The downregulation of miR-31 in LSCs promotes the maintenance of stemness. CONCLUSION: ES culture supernatant (ESC-CM) regulates the fate of LSCs in part by inhibiting the miR-31/FIH-1/P21 axis. This study may have a high impact on the expansion of LSCs in regenerative medicine, especially for ocular surface reconstruction.

HDAC inhibitors suppress c-Jun/Fra-1-mediated proliferation through transcriptionally downregulating MKK7 and Raf1 in neuroblastoma cells.

Activator protein 1 (AP-1) is a transcriptional factor composed of the dimeric members of bZIP proteins, which are frequently deregulated in human cancer cells. In this study, we aimed to identify an oncogenic AP-1 dimer critical for the proliferation of neuroblastoma cells and to investigate whether histone deacetylase inhibitors (HDACIs), a new generation of anticancer agents, could target the AP-1 dimer. We report here that HDACIs including trichostatin A, suberoylanilidehydroxamic acid, valproic acid and M344 can transcriptionally suppress both c-Jun and Fra-1, preceding their inhibition of cell growth. c-Jun preferentially interacting with Fra-1 as a heterodimer is responsible for AP-1 activity and critical for cell growth. Mechanistically, HDACIs suppress Fra-1 expression through transcriptionally downregulating Raf1 and subsequently decreasing MEK1/2-ERK1/2 activity. Unexpectedly, HDACI treatment caused MKK7 downregulation at both the protein and mRNA levels. Deletion analysis of the 5'-flanking sequence of the MKK7 gene revealed that a major element responsible for the downregulation by HDACI is located at -149 to -3 relative to the transcriptional start site. Knockdown of MKK7 but not MKK4 remarkably decreased JNK/c-Jun activity and proliferation, whereas ectopic MKK7-JNK1 reversed HDACI-induced c-Jun suppression. Furthermore, suppression of both MKK-7/c-Jun and Raf-1/Fra-1 activities was involved in the tumor growth inhibitory effects induced by SAHA in SH-SY5Y xenograft mice. Collectively, these findings demonstrated that c-Jun/Fra-1 dimer is critical for neuroblastoma cell growth and that HDACIs act as effective suppressors of the two oncogenes through transcriptionally downregulating MKK7 and Raf1.

SOX7 interferes with ß-catenin activity to promote neuronal apoptosis.

SOX7 mediates various developmental processes. However, its role in neuronal apoptosis remains unclear. In the present study, we investigated the expression pattern and role of SOX7 in potassium deprivation-induced rat cerebellar granule neuron apoptosis. Our results showed that both mRNA and protein levels of SOX7 were upregulated when potassium was deprived. SOX7 overexpression promoted neuronal apoptosis, whereas knockdown of SOX7 protected neurons against apoptosis. Moreover, we found that ß-catenin activity was suppressed during apoptosis and that ß-catenin inhibition was crucial for potassium deprivation-induced neuronal apoptosis. This suppression was mediated by an interaction between SOX7 and ß-catenin but not by protein degradation. Lastly, we showed that ß-catenin inhibition mediated the pro-apoptotic effect of SOX7. Together, our findings demonstrated that SOX7 interfered with ß-catenin activity to promote neuronal apoptosis, which acted as a novel signaling mechanism in neuronal cell death.

Annexin A2 knockdown inhibits hepatoma cell growth and sensitizes hepatoma cells to 5-fluorouracil by regulating ß-catenin and cyclin D1 expression.

Hepatocellular carcinoma (HCC) is one of the most common cancer types, and chemotherapy plays an important role in treatment of HCC. However, long­term treatment with chemotherapeutic drugs such as 5­fluorouracil (5­FU) often results in chemoresistance, and the underlying mechanisms remain unclear. In this study, we showed that the annexin A2 (ANXA2) protein is highly expressed in hepatoma cells compared to healthy cells. Knockdown of the ANXA2 gene inhibited hepatoma cell growth, and the underlying mechanism may involve cell cycle inhibition through downregulation of ß­catenin and cyclin D1. We also investigated the role of ANXA2 in chemotherapeutic treatment with 5­FU. 5­FU inhibited hepatoma cell growth, while ANXA2 overexpression reduced, and knockdown enhanced, the effects of 5­FU on hepatoma cell growth. Furthermore, ß­catenin and cyclin D1 were asscociated with the ANXA2­induced resistance. Taken together, our data suggest that the ANXA2 protein is a critical factor in HCC and that its downregulation can enhance chemotherapeutic treatment with 5­FU. ANXA2 may thus constitute a new therapeutic target for HCC.

The suppressive role of SOX7 in hepatocarcinogenesis.

SOX7 is a transcription factor mediating various developmental processes. However, its role in hepatocellular carcinoma (HCC) remains unclear. Here, we assessed the role of SOX7 in hepatocarcinogenesis. We found HCC samples exhibited lower levels of SOX7 mRNA and protein expression than non-tumor samples, and the expression of SOX7 was negatively correlated with tumor size. SOX7 expression was also reduced in four HCC cell lines (SMMC-7721, Hep3B, HepG2 and Huh 7). Overexpression of SOX7 could inhibit HCC cell growth, with G1to S phase arrest. In SOX7-overexpression cells, cyclin D1 and c-myc, two cell cycle promoters, were down-regulated. Moreover, ectopic expression of cyclin D1 or c-myc could override G1 to S pahse arrest induced by SOX7. Furthermore, overexpression of SOX7 suppressed tumor formation with down-regulation of cyclin D1 and c-myc in vivo. The expression of Ki-67, a proliferation marker, was also reduced in SOX7-overexpression tumors. Taken together, our study suggests that SOX7 plays an important inhibitory role in hepatocarcinogenesis, and might be a novel target for HCC therapy.