This article is aimed at exploring the relationship between the phosphatase 2A catalytic subunit Cα (PP2Acα, encoded by PPP2CA) and methyltransferase‐like 3 (METTL3) in the malignant progression of gastric cancer (GC). Through analyzing the bioinformatics database and clinical tissue immunohistochemistry results, we found that abnormal PP2Acα and METTL3 levels were closely related to the malignant progression of GC. To explore the internal connection between PP2Acα and METTL3 in the progression of GC, we carried out cellular and molecular experiments and finally proved that PP2Acα inhibition can upregulate METTL3 levels by activating ATM activity, thereby promoting the malignant progression of GC.

Disturbance of commensal intestinal microbiota is related to chronic inflammatory dermatosis. We analyzed the diversity of the gut microbiota to characterize the biological variation of psoriasis (Ps). Significant differences of gut microbiome profiles were revealed in murine model with psoriasis by sequencing 16S rRNA V3-V4 variable region. Group comparisons included the imiquimod cream (IMQ group, n=8), the imiquimod cream and antibiotics (ATB) (PC+IMQ group, n=8) and the healthy control (CTRL group, n=8). The gut microbiota existed in Ps groups including IMQ group and PC+IMQ group encompassed less diversity than controls, which were attributed to decreased presence of several taxa. The two Ps groups were characterized by significant reduction in firmicutes. In this study, microbiota of psoriasis was defined by an increase presence of Bacteroides. After treated with ATB, we found substantial increase of Lactobacillales but significant decrease of Clostridiales and Coriobacteriales. Relative lower abundance of multiple intestinal bacteria was observed in Ps groups. Although part of genera were concomitantly reduced in both IMQ and PC+IMQ conditions, we discovered the specialty of PC+IMQ group samples was that contained lower abundance of beneficial taxa. Characteristics of gut microbiota profiles in Ps mice were comparable to profiles in patients with Ps, which were related to alteration of specific inflammatory proteins in disease groups but were significantly different from control group. Thus, this study emphasizes the role of intestinal microbiota in the pathogenesis of Ps and provides new insight for investigating association between intestinal microbes and immune inflammation.

Colorectal cancer (CRC) is one of the most prevalent malignant tumors worldwide, with its pathogenesis tightly linked to the regulation of cell death. Ferroptosis plays a pivotal role in the initiation, progression, and treatment of CRC. In our previous studies, we demonstrated that PPP2CA knockdown enhances the malignant phenotype of CRC cells while increasing their susceptibility to ferroptosis, albeit this latter effect frequently mitigates the malignant phenotype. The present study aims to further elucidate the regulatory mechanism underlying the association between PPP2CA and ferroptosis.​ Lentiviral-mediated PPP2CA knockdown was performed in CRC cell lines HCT116 and SW480 to establish stable PPP2CA-knockdown models, and PPP2CA gene expression in these models was verified. Colony formation assays and scratch wound healing assays were used to assess the proliferative and migratory capacities of CRC cells after PPP2CA knockdown. Additionally, CRC samples from The Cancer Genome Atlas (TCGA) database were analyzed via bioinformatics approaches to identify ferroptosis-related genes closely correlated with PPP2CA, with subsequent validation in model cells. The STRING database was employed to analyze the interaction networks between PPP2CA and target ferroptosis-related genes, predict potential signaling pathways via which PPP2CA regulates cellular ferroptosis, and validate these findings in model cells.​ Compared with the control group, HCT116 and SW480 cells in the PPP2CA-knockdown group exhibited significantly enhanced proliferative and migratory capacities. Bioinformatics analysis identified the top 10 most significant ferroptosis-related genes associated with PPP2CA. Validation in model cells showed that the expression levels of transferrin receptor (TFRC) and acyl-CoA synthetase long-chain family member 4 (ACSL4) were significantly upregulated. STRING analysis and in-model-cell validation indicated that increased mTOR phosphorylation subsequent to PPP2CA knockdown could upregulate the protein expression levels of transferrin receptor (TfR, encoded by the TFRC gene) and ACSL4, and this effect could be reversed by the mTOR inhibitor rapamycin.​ Thus, PPP2CA knockdown enhances the malignant phenotype of CRC cells, while potentially upregulating the expression of ferroptosis-related genes TFRC and ACSL4 via the mTOR signaling pathway, thereby increasing ferroptosis sensitivity.