Juan-Hua Quan

Toxoplasma gondii infection poses potential risks to stem cell‐based therapeutic applications; however, the effects of parasite‐derived soluble factors on mesenchymal stem cells remain unclear. Here, we investigated the impact of T. gondii ‐derived soluble factors (Tg‐SFs) on human umbilical cord‐derived mesenchymal stem cells (hUC‐MSCs). hUC‐MSCs were exposed to Tg‐SFs generated in a Transwell co‐culture system, and cellular phenotypes and p53 signalling were analysed using integrated functional and molecular approaches. Tg‐SFs induced upper‐chamber multiplicity of infection (MOI)‐dependent cytotoxicity in hUC‐MSCs, accompanied by cytoskeletal remodelling and nuclear condensation. Tg‐SFs exposure caused marked G2/M phase accumulation, which was accompanied by reduced expression of Cyclin A2, Cyclin B1, and Cyclin E2 and increased p21 expression. In addition, Tg‐SFs exposure reduced phosphorylation of CDK1 at Thr161. Tg‐SFs‐exposed hUC‐MSCs underwent significant apoptosis, as evidenced by PARP and Caspase‐3 cleavage. Mechanistically, Tg‐SFs promoted accumulation of total p53 protein and selective phosphorylation of p53 at Ser15 and Ser392, and modulated Bcl‐2 family proteins by upregulating Bax, BID, Bak, Bad, and Puma while downregulating Bcl‐xL and Mcl‐1. Pharmacological inhibition of p53 with PFT‐α and siRNA‐mediated p53 knockdown partially reversed these effects, indicating that p53 signalling contributes substantially, but not exclusively, to Tg‐SFs‐induced mitochondrial apoptosis. These findings indicate that T. gondii ‐derived soluble factors impair hUC‐MSC viability through G2/M phase accumulation and p53‐associated mitochondrial apoptosis, highlighting a potential safety consideration for MSC‐based applications under parasite‐associated conditions.

Gefitinib, a selective EGFR-tyrosine kinase inhibitor, exhibits potent cytotoxic effects on colorectal cancer cells, though its precise mechanisms are not fully understood. In this study, we demonstrated that gefitinib induces a dose-dependent cytotoxic response in Caco-2 cells, characterized by disrupted microtubule networks, impaired migration, and reduced viability. Gefitinib triggered apoptosis, as indicated by increased levels of cleaved caspase-3, PARP, and elevated late apoptosis rates. Mechanistically, gefitinib-induced endoplasmic reticulum (ER) stress, marked by the upregulation of IRE1α, CHOP, and ATF4. ER stress inhibition by 4-PBA significantly reduced apoptosis and restored mitochondrial membrane potential (MMP). Additionally, gefitinib-induced apoptosis was mediated through the mitochondrial pathway, reflected by the modulation of Bcl-2 family proteins, including the upregulation of Bax and Bim. Inhibition of the IRE1α-mediated JNK/p38 MAPK pathway further mitigated gefitinib-induced apoptosis and restored MMP. These findings highlight the critical role of ER stress and the IRE1α-JNK/p38 MAPK axis in gefitinib-induced mitochondrial apoptosis, offering potential therapeutic targets for colorectal cancer.

As a chronic inflammatory bowel disease, the pathogenesis of ulcerative colitis (UC) has not been fully elucidated. N6-methyladenosine (m6A) modification, observed in various RNAs, is implicated in inflammatory bowel diseases. Methyltransferase-like 14 (METTL14) is the major subunit of the methyltransferase complex catalyzing m6A modifications. Here, we designated to examine the regulatory effects and mechanisms of METTL14 on long non-coding RNA (lncRNA) during UC progression. METTL14 knockdown decreased cell viability, promoted apoptosis, increased cleaved PARP and cleaved Caspase-3 levels, while reducing Bcl-2 levels. METTL14 knockdown also led to a significant increase in NF-κB pathway activation and inflammatory cytokine production in the Caco-2 cells treated with TNF-α. Moreover, the suppression of METTL14 aggravated colonic damage and inflammation in our dextran sulfate sodium (DSS)-induced murine colitis model. METTL14 silencing suppressed DHRS4-AS1 expression by reducing the m6A modification of DHRS4-AS1 transcripts. Furthermore, DHRS4-AS1 mitigated inflammatory injury by targeting the miR-206/adenosine A3 receptor (A3AR) axis. DHRS4-AS1 overexpression counteracted the enhancing impact of METTL14 knockdown on TNF-α-induced inflammatory injury in Caco-2 cells. In conclusion, our findings suggest that METTL14 protects against colonic inflammatory injury in UC via regulating the DHRS4-AS1/miR-206/A3AR axis, thus representing a potential therapeutic target for UC.

Ulcerative colitis (UC) is a chronic and relapsing inflammatory bowel disease (IBD) characterized by colorectal inflammation. The N6-methyladenosine (m6A) modification of RNA regulates gene expression through the modulation of RNA metabolism, thus influencing various physiological and pathological processes. The aim of this study was to investigate the biological function of m6A methyltransferase METTL14 in colorectal epithelial cell inflammation. Bioinformatics analysis indicated that METTL14 expression was decreased in UC and was associated with disease severity and immune infiltration. We also noted a downregulation of METTL14 expression and a decrease in the total m6A RNA levels in TNF-α-stimulated Caco-2 cells. Moreover, METTL14 knockdown promoted inflammation and inhibited autophagy in TNF-α-stimulated Caco-2 cells, as indicated by the upregulation of NF-κB signaling and pro-inflammatory cytokine expression as well as LC3B protein downregulation. Treatment with the autophagy activator Torin-1 ameliorated the pro-inflammatory effects of METTL14 silencing. Furthermore, METTL14 knockdown significantly reduced the expression of ATG5. ATG5 overexpression could nullify the pro-inflammatory effect of METTL14 knockdown in TNF-α-stimulated Caco-2 cells. Mechanistically, METTL14 knockdown promoted ATG5 mRNA degradation, and luciferase analysis identified ATG5 as a target of m6A modification by METTL14. Taken together, silencing METTL14 promoted inflammation in Caco-2 cells via the downregulation of ATG5. Our findings revealed the importance of the m6A modification in colonic inflammation and autophagy, indicating that targeting METTL14 might be a potential therapeutic strategy for anti-inflammatory treatment in UC.

Gastric cancer represents a significant global health concern, necessitating the exploration of novel therapeutic options. Diosmetin, a natural flavonoid derived from citrus and vegetables, has demonstrated promising anti-tumor activity against various tumor cells. However, the potential anticancer effect of diosmetin in gastric cancer and its underlying mechanism have yet to be elucidated. In this study, we aimed to investigate the impact of diosmetin on cell proliferation, migration, cell cycle progression and apoptosis in human gastric cancer HGC-27 cells. Our findings revealed that diosmetin effectively suppressed cell proliferation, induced G2/M phase cell cycle arrest, and triggered cell apoptosis. Mechanistically, diosmetin downregulated the expression of antiapoptotic proteins Bcl-2 and Bcl-xL, while upregulated the level of proapoptotic proteins such as Bax, cleaved PARP and cleaved caspase-3. Additionally, diosmetin inhibited Akt and FoxO1 phosphorylation, while activated the MAPK signaling pathway. Notably, pretreatment of IGF-1, an Akt activator, attenuated the diosmetin-induced apoptosis. Furthermore, pretreatment with SP600125, a JNK inhibitor, significantly reduced the protein level of LC3B, while promoted the expression of cleaved caspase-3 and cleaved PARP. Collectively, our results suggest that diosmetin holds promise as an effective therapeutic agent against gastric cancer by inducing apoptosis through inhibition of the Akt/FoxO1 pathway and promoting protective autophagy via the MAPK/JNK signaling pathway.

Gastric cancer represents a significant global health concern, necessitating the exploration of novel therapeutic options. Diosmetin, a natural flavonoid derived from citrus and vegetables, has demonstrated promising anti-tumor activity against various tumor cells. However, the potential anticancer effect of diosmetin in gastric cancer and its underlying mechanism have yet to be elucidated. In this study, we aimed to investigate the impact of diosmetin on cell proliferation, migration, cell cycle progression and apoptosis in human gastric cancer HGC-27 cells. Our findings revealed that diosmetin effectively suppressed cell proliferation, induced G2/M phase cell cycle arrest, and triggered cell apoptosis. Mechanistically, diosmetin downregulated the expression of antiapoptotic proteins Bcl-2 and Bcl-xL, while upregulated the level of proapoptotic proteins such as Bax, cleaved PARP and cleaved caspase-3. Additionally, diosmetin inhibited Akt and FoxO1 phosphorylation, while activated the MAPK signaling pathway. Notably, pretreatment of IGF-1, an Akt activator, attenuated the diosmetin-induced apoptosis. Furthermore, pretreatment with SP600125, a JNK inhibitor, significantly reduced the protein level of LC3B, while promoted the expression of cleaved caspase-3 and cleaved PARP. Collectively, our results suggest that diosmetin holds promise as an effective therapeutic agent against gastric cancer by inducing apoptosis through inhibition of the Akt/FoxO1 pathway and promoting protective autophagy via the MAPK/JNK signaling pathway.