The role of Reg IV in colorectal cancer, as a potential therapeutic target

Elevated Risk of Adverse Prognosis in Patients with T2-3 Stage Breast Cancer Exhibiting Non-Pathological Complete Response Following Neoadjuvant Chemotherapy: Significance of Regenerating Islet-Derived Family Member 4

Objective

In this study, we aimed to establish the role of regenerating islet-derived family member 4 (Reg IV) as an independent risk factor and prognostic predictor in patients with T2-3 stage breast cancer who exhibit a non-pathological complete response (non-pCR) following neoadjuvant chemotherapy (NACT). Additionally, we examined the potential correlation and interaction between Reg IV and epidermal growth factor receptor (EGFR).

Methods

A total of 67 patients with T2-3 stage breast cancer exhibiting non-pCR after NACT between September 2019 and December 2021 were included in this study. The analysis involved Kaplan-Meier survival comparisons, pooled hazard ratios for risk quantification, Cox regression analysis to isolate the impact of Reg IV on prognosis, Riskplots for visualizing risk profiles, and SHAP analysis to assess the importance of variables in predicting outcomes.

Results

The findings indicate that patients positive for Reg IV had a significantly poorer prognosis (HR: 2.62, 95% CI: 1.06-6.47). Co-expression of Reg IV and EGFR was associated with the worst outcomes compared to patients negative for both markers. Cox regression analysis confirmed the independent prognostic impact of Reg IV (HR: 2.63, 95% CI: 1.66-3.59). Riskplot analysis showed that patients positive for both Reg IV and EGFR predominantly experienced disease progression. SHAP analysis further reinforced the significant effect of Reg IV on the disease course, without substantial interaction with EGFR.

Conclusion

Reg IV may serve as an independent risk factor and predictive marker for adverse outcomes in patients with T2-3 stage breast cancer who do not achieve non-pCR following NACT.

Regenerating gene 4 promotes chemoresistance of colorectal cancer by affecting lipid droplet synthesis and assembly

BACKGROUND

Regenerating gene 4 (REG4) has been proved to be carcinogenic in some cancers, but its manifestation and possible carcinogenic mechanisms in colorectal cancer (CRC) have not yet been elucidated. Our previous study found that the drug resistance of CRC cells may be closely linked to their fat metabolism.

AIM

To explore the role of REG4 in CRC and its association with lipid droplet formation and chemoresistance.

METHODS

We conducted a meta-analysis and bioinformatics and pathological analyses of REG4 expression in CRC. The effects of REG4 on the phenotypes and related protein expression were also investigated in CRC cells. We detected the impacts of REG4 on the chemoresistance and lipid droplet formation in CRC cells. Finally, we analyzed how REG4 regulated the transcription and proteasomal degradation of lipogenic enzymes in CRC cells.

RESULTS

Compared to normal mucosa, REG4 mRNA expression was high in CRC (P < 0.05) but protein expression was low. An inverse correlation existed between lymph node and distant metastases, tumor-node-metastasis staging or short overall survival and REG4 mRNA overexpression (P < 0.05), but vice versa for REG4 protein expression. REG4-related genes included: Chemokine activity; taste receptors; protein-DNA and DNA packing complexes; nucleosomes and chromatin; generation of second messenger molecules; programmed cell death signals; epigenetic regulation and DNA methylation; transcription repression and activation by DNA binding; insulin signaling pathway; sugar metabolism and transfer; and neurotransmitter receptors (P < 0.05). REG4 exposure or overexpression promoted proliferation, antiapoptosis, migration, and invasion of DLD-1 cells in an autocrine or paracrine manner by activating the epidermal growth factor receptor-phosphoinositide 3-kinase-Akt-nuclear factor-κB pathway. REG4 was involved in chemoresistance not through de novo lipogenesis, but lipid droplet assembly. REG4 inhibited the transcription of acetyl-CoA carboxylase 1 (ACC1) and ATP-citrate lyase (ACLY) by disassociating the complex formation of anti-acetyl (AC)-acetyl-histone 3-AC-histone 4-inhibitor of growth protein-5-si histone deacetylase;-sterol-regulatory element binding protein 1 in their promoters and induced proteasomal degradation of ACC1 or ACLY.

CONCLUSION

REG4 may be involved in chemoresistance through lipid droplet assembly. REG4 reduces expression of de novo lipid synthesis key enzymes by inhibiting transcription and promoting ubiquitination-mediated proteasomal degradation.

Regenerating Family Member 4 (Reg4) Enhances 5-Fluorouracil Resistance of Gastric Cancer Through Activating MAPK/Erk/Bim Signaling Pathway

BACKGROUND Reg4, a member of the Reg multigene family, is highly upregulated in many gastrointestinal cancers including gastric cancer (GC). The enhanced expression of Reg4 is associated with the resistance of GC to 5-fluorouracil (5-FU), while the underlying mechanism is not clear. The aim of the present study was to explore the resistant mechanism underlying 5-FU resistance. MATERIAL AND METHODS Reg4 expression was assessed by Western blot analysis for SGC-7901, BGC-823, AGS, MKN28, and MKN45. Synthetic short single strand RNA oligonucleotides and Flag-Reg4 plasmid were used to investigate the biological function of Reg4 in vitro. The cell viability assay was performed by MTT. Flow cytometry was carried out to measure the apoptosis caused by 5-FU. Reverse-transcriptase quantitative polymerase chain reaction (RT-qPCR) was used to examine the expression of 5-FU metabolism related enzymes. The effect of Reg4 on intracellular signaling was evaluated by Western blot. RESULTS Western blot analysis of 5 GC cells showed that Reg4 was low or null in SGC-7901 and BGC-823, while high in AGS, MKN28, and MKN45. Over-expression of flag-Reg4 in SGC-7901 led to an increase in cell viability and lower apoptosis with 5-FU treatment. In contrast, siRNA knockdown of Reg4 enhanced 5-FU induced apoptosis. However, over-expression or knockdown of Reg4 had no significant influence on the expression of 5-FU metabolic enzymes. Further investigation revealed that Reg4 could activate Erk1/2-Bim-caspase3 cascade. CONCLUSIONS Reg4 inhibited apoptosis through regulating MAPK/Erk/Bim signaling pathway and thereby enhanced the resistance of GC to 5-FU.

Overexpression of Long Non-Coding RNA TUG1 Promotes Colon Cancer Progression

Background

Colon cancer is one of the most prevalent and deadly cancers worldwide. It is still necessary to further define the mechanisms and explore therapeutic targets of colon cancer. Dysregulation of long noncoding RNAs (lncRNAs) has been shown to be correlated with diverse biological processes, including tumorigenesis. This study aimed to characterize the biological mechanism of taurine-upregulated gene 1 (TUG1) in colon cancer.

Material/Methods

qRT-PCR was used to analyze the expression level of TUG1 and p63 in 75 colon cancer tissues and the matched adjacent non-tumor tissue. In vitro, cultured colon cancer cell lines HCT-116 and LoVo were used as cell models. TUG1 and p63 were silenced via transferring siRNA into HCT-116 or LoVo. The effects of TUG1 were investigated by examining cell proliferation, apoptosis, and migration.

Results

Among the 75 colon cancer cases, the expression of TUG1 was significantly higher in colon cancer tissues compared with the matched adjacent non-tumor tissue, while p63 expression was lower in the tumor tissue. In HCT-116 and LoVo, the expression of TUG1 was significantly increased by p63 siRNA transfection. Furthermore, down-regulation of TUG1 by siRNA significantly inhibited the cell proliferation and promoted colon cancer cell apoptosis. In addition, inhibition of TUG1 expression significantly blocked the cell migration ability of colon cancer cells.

Conclusions

LncRNA TUG1 may serve as a potential oncogene for colon cancer. Overexpressed TUG1 may contribute to promoting cell proliferation and migration in colon cancer cells.