MiR-509-3p is oncogenic, targets the tumor suppressor PHLPP2, and functions as a novel tumor adjacent normal tissue based prognostic biomarker in colorectal cancer

Vitamin D receptor regulates methyltransferase like 14 to mitigate colitis-associated colorectal cancer

Colitis-associated colorectal cancer (CAC), a serious complication of ulcerative colitis (UC), is associated with a poor prognosis. The vitamin D receptor (VDR) is recognized for its protective role in UC and CAC through the maintenance of intestinal barrier integrity and the regulation of inflammation. This study demonstrates a significant reduction in m6A-related genes, particularly methyltransferase like 14 (METTL14), in UC and CAC patients and identifies an association between METTL14 and VDR. In the azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced mouse model, vitamin D treatment increases METTL14 expression and reduces tumor burden, while Vdr-knockout mice exhibit lower METTL14 levels and increased tumorigenesis. In vitro, the VDR agonist calcipotriol upregulates METTL14 in NCM460 cells, with this effect attenuated by VDR knockdown. VDR knockdown in DLD-1 colon cancer cells decreases METTL14 expression and promotes proliferation, which is reversed by METTL14 overexpression. Mechanistic studies reveal that VDR regulates METTL14 expression via promoter binding, modulating key target genes such as SOX4, DROSH, and PHLPP2. This study highlights the role of the VDR-METTL14 axis as a protective mechanism in CAC and suggests its potential as a therapeutic target for preventing and treating CAC.

MiR-509-3p promotes gastric cancer development by activating FOXM1-mediated p38/MK2 pathway

Gastric cancer (GC), a malignant tumor, is highly prevalent, particularly in Asia. miR-509-3p plays a crucial role in regulating tumorigenesis, but its mechanism in GC remains unclear. Potential targets of miR-509-3p were identified through database analyses (miRWalk, TargetScan, ENCORI, and TCGA). The binding site between miR-509-3p and forkhead box protein M1 (FOXM1) was confirmed using a dual-luciferase assay. CCK-8, EdU, Transwell, wound healing assays, flow cytometry, and Western blot analysis were employed to examine changes in proliferation, migration, invasion, apoptosis, FOXM1, and the p38 MAPK (p38)/MAPK-activated protein kinase 2 (MK2) pathway in GC cells (MNK-45 and HGC-27) after miR-509-3p overexpression or knockdown, FOXM1 overexpression, and application of the p38 pathway agonist Anisomycin. The size and weight of subcutaneous xenografts were measured, and the effects of miR-509-3p overexpression were analyzed through histopathological staining (Tunel immunofluorescence, HE staining, Ki67, and FOXM1 immunohistochemistry). The results showed that overexpression of miR-509-3p suppressed proliferation, migration, and invasion, while accelerating apoptosis. Knockdown of miR-509-3p promoted malignant progression. miR-509-3p inhibited GC by regulating FOXM1-mediated p38/MK2 pathway activation, and miR-509-3p mimics restrained tumor growth in vivo through this pathway. In conclusion, miR-509-3p suppresses GC malignant progression by regulating FOXM1-mediated p38/MK2 pathway activation.

Differentially Expressed Somatostatin (SST) and Its Receptors (SST1-5) in Sporadic Colorectal Cancer and Normal Colorectal Mucosa

BACKGROUND/OBJECTIVES

Colorectal cancer (CRC) is one of the most common human malignancies worldwide. The somatotropin-releasing inhibitory factor/somatostatin (SRIF/SST) acts through activation of five membrane receptors (SSTRs, SST1-5). The diagnostic and prognostic role of these peptides in sporadic CRC remains unclear. This study aimed to determine the role of tissue expression of SST and all SSTRs in the pathogenesis, diagnosis, and prognosis of sporadic CRC.

METHODS

The expression of SST and all SSTRs was assessed in the tissues of CRC patients, control colorectal mucosa and lymph node metastasis from the same patients using real-time quantitative polymerase chain reaction (RT-qPCR) and immunohistochemistry (IHC).

RESULTS

Decreased SST (mRNA and peptide) and higher SST2 and SST5 (mRNA and peptide) expression in CRC vs. control was noted. A negative correlation between SST mRNA expression and patient's age in CRC and control groups were observed. IHC study confirmed the coexpression of SSTRs in all tissue groups and significant dependence on the cellular localization. Immunoexpression of SST2 and SST3 showed the most correlations with clinicopathological data in CRC patients. Interestingly, only control tissue showed differences in SST1-5 expression depending on the colon segment.

CONCLUSIONS

Reduced SST expression in CRC indicates a weakening in its antitumor effect in this cancer in vivo. Overexpression of SST2 and SST5 in CRC suggests that these receptors play an important role in the pathogenesis of this cancer. Analysis of SST1-5 tissue expression allows for differentiation between the mucinous and nonmucinous CRC subtypes. The coexpression of all SST1-5 and overexpression of not only SST2 and SST5 in CRC may have applications for future therapy based on the SRIF system in sporadic CRC.

Helicobacter pylori infection induces gastric cancer cell malignancy by targeting HOXA-AS2/miR-509-3p/MMD2 axis

BACKGROUND

Helicobacter pylori (Hp) infection is considered to be the strongest risk factor for gastric cancer (GC). Long non-coding RNA HOXA cluster antisense RNA 2 (HOXA-AS2) has been indicated to be significantly related to Hp infection in GC patients.

OBJECTIVE

To investigate the detailed role and molecular mechanism of lncRNA HOXA-AS2 in Hp-induced GC.

METHODS

GC cells were treated with Hp filtrate for cell infection. Bioinformatics tools were utilized for survival analysis and prediction of HOXA-AS2 downstream molecules. Western blotting and RT-qPCR were utilized for assessing protein and RNA levels, respectively. Flow cytometry, colony formation and CCK-8 assays were implemented for testing HOXA-AS2 functions in Hp-infected GC cells. HOXA-AS2 localization in cells was determined by subcellular fractionation assay. The relationship between RNAs were measured by luciferase reporter assay.

RESULTS

Hp infection induced HOXA-AS2 upregulation in GC cells. Knocking down HOXA-AS2 restrained cell proliferation but promoted cell apoptosis with Hp infection. HOXA-AS2 bound to miR-509-3p, and miR-509-3p targeted monocyte to macrophage differentiation associated 2 (MMD2). Overexpressing MMD2 reversed HOXA-AS2 depletion-mediated suppression on cell aggressiveness with Hp infection.

CONCLUSION

Hp infection induces the aggressiveness of GC cells by regulating HOXA-AS2/miR-509-3p/MMD2 axis.

Recent Developments in Diagnostic and Prognostic Biomarkers for Colorectal Cancer: A Narrative Review

BACKGROUND

Colorectal cancer was reported as the second most common cause of cancer death worldwide, in the year 2020. This disease is an important public health problem considering its high incidence and mortality rates.

SUMMARY

The molecular events that lead to colorectal cancer include genetic and epigenetic abnormalities. Some of the most important molecular mechanisms involved include the APC/β-catenin pathway, the microsatellite pathway, and the CpG island hypermethylation. Evidence in the literature supports a role for the microbiota in the development of colon carcinogenesis, and specific microbes may contribute to or prevent carcinogenesis. Progress in prevention, screening, and management has improved the overall prognosis of the disease when diagnosed at an early stage; yet metastatic disease continues to have a poor long-term prognosis due to late-stage diagnosis and treatment failure. Biomarkers are a key tool for early detection and prognosis and aim to reduce morbidity and mortality associated with colorectal cancer. The main focus of this narrative review is to provide an update on the recent development of diagnostic and prognostic biomarkers in stool, blood, and tumor tissue samples.

KEY MESSAGES

The review focuses on recent investigations in microRNAs, cadherins, Piwi-interacting RNAs, circulating cell-free DNA, and microbiome biomarkers which can be applied for the diagnosis and prognosis of colorectal cancer.