LRF inhibits p53 expression in colon cancer cells via modulating DAP5 activity

Pokemon inhibits Bim transcription to promote the proliferation, anti-anoikis, invasion, histological grade, and dukes stage of colorectal neoplasms

PURPOSE

This study aims to determine whether Pokemon regulates Bim activity in colorectal carcinoma (CRC) carcinogenesis.

METHODS

Clinical tissue samples were analyzed to detect the expression and clinicopathological significance of Pokemon and Bim in CRC. Proliferation, apoptosis, and invasion assays were conducted to identify the regulatory effect of Pokemon on Bim. The combined treatment effects of Pokemon knockdown and diamminedichloroplatinum (DDP) were also examined.

RESULTS

Immunohistochemical analysis of 80 samples of colorectal epithelia (CRE), 80 cases of colorectal adenoma (CRA), and 160 of CRC samples revealed protein expression rates of 23.8%, 38.8%, and 70.6% for Pokemon, and 88.8%, 73.8%, and 31.9% for Bim, respectively. A significant negative correlation was observed between Pokemon and Bim expression across the CRE, CRA, and CRC lesion stages. In CRC, higher Pokemon and lower Bim expression correlated with higher histological grades, advanced Dukes stages, and increased cancer invasion. In both LoVo and HCT116 cells, overexpression of Pokemon significantly reduced Bim expression, leading to increased proliferation, resistance to anoikis, and cell invasion. Additionally, Pokemon overexpression significantly decreased DDP-induced Bim expression, reduction of anti-apoptosis and invasion, whereas Pokemon knockdown resulted in the opposite effects.

CONCLUSION

These findings suggest that Pokemon inhibits Bim transcription, thereby promoting CRC proliferation, resistance to apoptosis, invasion, and advancing histological grade and Dukes staging. Pokemon knockdown enhances the therapeutic efficacy of DDP in the treatment of CRC.

High Expression of EIF4G2 Mediated by the TUG1/Hsa-miR-26a-5p Axis Is Associated with Poor Prognosis and Immune Infiltration of Gastric Cancer

Objective

Eukaryotic translation initiation factor 4 gamma 2 (EIF4G2) is involved in the occurrence and development of various tumors. However, the effect of EIF4G2 in gastric cancer (GC) has not been fully explored. The purpose of this study was to explore the function and mechanism of EIF4G2 in GC.

Methods

The Tumor Immune Estimation Resource 2.0 database was used to analyze EIF4G2 expression in various cancers and the relationship between EIF4G2 expression and tumor-infiltrating immune cells. Gene Expression Profiling Interactive Analysis was utilized to assess the EIF4G2 expression level and its effect on survival in GC. UALCAN was conducted to analyze EIF4G2 expression in various subgroups of GC. The Kaplan–Meier plotter was employed for survival analysis. Receiver operator characteristic (ROC) curve analysis was applied to evaluate the diagnostic role of EIF4G2 in GC. LinkedOmics was used to identify the co-expressed genes and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathways. The Tumor-Immune System Interaction database was employed to analyze the correlation between EIF4G2 expression and tumor-infiltrating lymphocytes. The starBase web platform was used to predict the upstream microRNAs and long noncoding RNAs.

Results

EIF4G2 expression was upregulated in GC tissues compared to normal controls. High expression of EIF4G2 indicated poor prognosis in GC. ROC analysis revealed that EIF4G2 had good diagnostic ability to distinguish GC from normal tissues. Immune infiltration analysis indicated that EIF4G2 expression may be involved in the modulation of tumor immune infiltration in GC. Finally, we determined that the Taurine Upregulated 1 (TUG1)/hsa-miR-26a-5p/EIF4G2 axis was the most likely regulatory pathway involved in GC development.

Conclusions

EIF4G2 was upregulated in GC and elevated expression of EIF4G2 indicated unfavorable prognosis. Moreover, EIF4G2 expression may be involved in the regulation of tumor immune cell infiltration. The TUG1/hsa-miR-26a-5p axis is a likely upstream regulatory mechanism of EIF4G2 in GC. EIF4G2 may thus serve as a prognosis biomarker and present a new therapeutic target.

Role of ZBTB7A zinc finger in tumorigenesis and metastasis

The zinc finger and BTB (broad-complex, tramtrack and bric a brac) domain containing protein 7A (ZBTB7A) is a pleiotropic transcription factor that plays an important role in various stages of cell proliferation, differentiation, and other developmental processes. ZBTB7A is a member of the POK family that directly and specifically binds to short DNA recognition sites located near their target genes thereby acting as transcriptional activator or repressor. ZBTB7A overexpression has been associated with tumorigenesis and metastasis in various human cancer types, including breast, prostate, lung, ovarian, and colon cancer. However in some instances downregulation of ZBTB7A results in tumor progression, suggesting its role as a tumor suppressor. ZBTB7A is involved with complicated regulatory networks which include protein-protein and protein-nucleic acid interactions. ZBTB7A involvement in cancer progression and metastasis is perhaps enabled through the regulation of various signaling pathways depending on the type and genetic context of cancer. The association of ZBTB7A with other proteins affects cancer aggressiveness, therapeutic resistance and clinical outcome. This review focuses on the involvement of ZBTB7A in various signaling pathways and its role in cancer progression. We will also review the literature on ZBTB7A and cancer which could be potentially explored for its therapeutic implications.

ZBTB7A functioned as an oncogene in colorectal cancer

Background

Despite zinc finger and BTB domain-containing 7A (ZBTB7A) documented importance in multiple tumors, the function and clinical value in Colorectal cancer (CRC) remain elusive. The aim of this study was to evaluate the functional roles and the clinical value of ZBTB7A in CRC progression.

Methods

The level of ZBTB7A was detected in a large cohort of CRC patients (n = 189) by immunohistochemistry (IHC), and we analyzed the diagnostic and prognostic value of the protein. In addition, the functional roles of ZBTB7A on CRC were explored in vitro and in vivo.

Results

Survival analyses indicated that patients with high ZBTB7A expression made the prognosis worse (P = 0.024). Functionally, knockdown of ZBTB7A could markedly inhibit tumor proliferation in vitro and in vivo, whereas ZBTB7A overexpression displayed the opposite results.

Conclusions

ZBTB7A was associated with poor survival outcomes and functioned as an oncogene in CRC patients, indicating that it is a potential prognostic biomarker and therapeutic target for CRC patients.

Emerging role of ZBTB7A as an oncogenic driver and transcriptional repressor

ZBTB7A is a member of the POK family of transcription factors that possesses a POZ-domain at the N-terminus and Krüppel-like zinc-finger at the c-terminus. ZBTB7A was initially isolated as a protein that binds to the inducer of the short transcript of HIV-1 virus TAT gene promoter. The protein forms a homodimer through protein-protein interaction via the N-terminus POZ-domains. ZBTB7A typically binds to the DNA elements through its zinc-finger domains and represses transcription both by modification of the chromatin organization and through the direct recruitment of transcription factors to gene regulatory regions. ZBTB7A is involved in several fundamental biological processes including cell proliferation, differentiation, and development. It also participates in hematopoiesis, adipogenesis, chondrogenesis, cellular metabolism and alternative splicing of BCLXL, DNA repair, development of oligodendrocytes, osteoclast and unfolded protein response. Aberrant ZBTB7A expression promotes oncogenic transformation and tumor progression, but also maintains a tumor suppressive role depending on the type and genetic context of cancer. In this comprehensive review we provide information about the structure, function, targets, and regulators of ZBTB7A and its role as an oncogenic driver and transcriptional repressor in various human diseases.

The multi-faceted functioning portrait of LRF/ZBTB7A

Transcription factors (TFs) consisting of zinc fingers combined with BTB (for broad-complex, tram-track, and bric-a-brac) domain (ZBTB) are a highly conserved protein family that comprises a multifunctional and heterogeneous group of TFs, mainly modulating cell developmental events and cell fate. LRF/ZBTB7A, in particular, is reported to be implicated in a wide variety of physiological and cancer-related cell events. These physiological processes include regulation of erythrocyte maturation, B/T cell differentiation, adipogenesis, and thymic insulin expression affecting consequently insulin self-tolerance. In cancer, LRF/ZBTB7A has been reported to act either as oncogenic or as oncosuppressive factor by affecting specific cell processes (proliferation, apoptosis, invasion, migration, metastasis, etc) in opposed ways, depending on cancer type and molecular interactions. The molecular mechanisms via which LRF/ZBTB7A is known to exert either physiological or cancer-related cellular effects include chromatin organization and remodeling, regulation of the Notch signaling axis, cellular response to DNA damage stimulus, epigenetic-dependent regulation of transcription, regulation of the expression and activity of NF-κB and p53, and regulation of aerobic glycolysis and oxidative phosphorylation (Warburg effect). It is a pleiotropic TF, and thus, alterations to its expression status become detrimental for cell survival. This review summarizes its implication in different cellular activities and the commonly invoked molecular mechanisms triggered by LRF/ZBTB7A’s orchestrated action.