Vitamin D suppresses CD133+/CD44 + cancer stem cell stemness by inhibiting NF-κB signaling and reducing NLRP3 expression in triple-negative breast cancer.

BACKGROUND AND OBJECTIVE: This study aims to investigate the role of Vitamin D (VD) in regulating the stemness and survival of CD133+/CD44 + breast cancer stem cells, and to explore the role of NLRP3 in this process. METHODS: Breast cancer tissues were collected for RXRα and VDR expression analysis. A triple-negative breast cancer cell line was cultured and stem-like cells (CD133 + CD44+) isolated using flow cytometry. These cells were treated with VD, analyzing their stem-like properties, apoptosis and proliferation, as well as P65 nuclear expression and NLRP3 expression. After NLRP3 inflammasome activator treatment, the parameters were reassessed. RXRα and VDR interaction was confirmed using co-immunoprecipitation (CoIP). Finally, a subcutaneous xenograft model of triple-negative breast cancer was treated with VD and subsequently analyzed for stem-like properties, proliferation, apoptosis, and NLRP3 expression levels. RESULTS: CD133+/CD44 + stem cells expressed high levels of SOX2 and OCT4. VD treatment resulted in a significant decrease in SOX2 and OCT4 expression, fewer sphere-forming colonies, lower proliferation ability, and more apoptosis. Additionally, VD treatment inhibited NF-κB signaling and reduced NLRP3 expression. The NLRP3 activator BMS-986,299 counteracted the effects of VD in vitro. In vivo, VD inhibited the growth of breast cancer stem cells, reducing both tumor volume and weight, and decreased NLRP3, SOX2, and OCT4 expression within tumor tissues. CONCLUSION: Findings elucidate that VD mediates the modulation of stemness in CD133+/CD44 + breast cancer stem cells through the regulation of NLRP3 expression. The research represents novel insights on the implications for the application of VD in cancer therapies.

Comparison of 6-min walk test distance vs. estimated maximum oxygen consumption for predicting postoperative pulmonary complications in patients undergoing upper abdominal surgery: a prospective cohort study.

OBJECTIVE: The present study aims to evaluate the predictive ability of estimated maximum oxygen consumption (e[Formula: see text]O2max) and 6-min walk distance (6MWD) for postoperative pulmonary complications (PPCs) in adult surgical patients undergoing major upper abdominal surgery. METHOD: This study was conducted by collecting data prospectively from a single center. The two predictive variables in the study were defined as 6MWD and e[Formula: see text]O2max. Patients scheduled for elective major upper abdominal surgery from March 2019 to May 2021 were included. The 6MWD was measured for all patients before surgery. e[Formula: see text]O2max was calculated using the regression model of Burr, which uses 6MWD, age, gender, weight, and resting heart rate (HR) to predict aerobic fitness. The patients were categorized into PPC and non-PPC group. The sensitivity, specificity, and optimum cutoff values for 6MWD and e[Formula: see text]O2max were calculated to predict PPCs. The area under the receiver operating characteristic curve (AUC) of 6MWD or e[Formula: see text]O2max was constructed and compared using the Z test. The primary outcome measure was the AUC of 6MWD and e[Formula: see text]O2max in predicting PPCs. In addition, the net reclassification index (NRI) was calculated to assess ability of e[Formula: see text]O2max compared with 6MWT in predicting PPCs. RESULTS: A total of 308 patients were included 71/308 developed PPCs. Patients unable to complete the 6-min walk test (6MWT) due to contraindications or restrictions, or those taking beta-blockers, were excluded. The optimum cutoff point for 6MWD in predicting PPCs was 372.5 m with a sensitivity of 63.4% and specificity of 79.3%. The optimum cutoff point for e[Formula: see text]O2max was 30.8 ml/kg/min with a sensitivity of 91.6% and specificity of 79.3%. The AUC for 6MWD in predicting PPCs was 0.758 (95% confidence interval (CI): 0.694-0.822), and the AUC for e[Formula: see text]O2max was 0.912 (95%CI: 0.875-0.949). A significantly increased AUC was observed in e[Formula: see text]O2max compared to 6MWD in predicting PPCs (P < 0.001, Z = 4.713). And compared with 6MWT, the NRI of e[Formula: see text]O2max was 0.272 (95%CI: 0.130, 0.406). CONCLUSION: The results suggested that e[Formula: see text]O2max calculated from the 6MWT is a better predictor of PPCs than 6MWD in patients undergoing upper abdominal surgery and can be used as a tool to screen patients at risk of PPCs.

Vitamin D-induced vitamin D receptor expression induces tamoxifen sensitivity in MCF-7 stem cells via suppression of Wnt/ß-catenin signaling.

Objective: Cancer stem cells (CSCs) are responsible for the drug resistance of breast cancers. Vitamin D deficiency promotes tumor resistance. The present study examined the effect of vitamin D and vitamin D receptor (VDR) expression on the tamoxifen resistance of CSCs. Methods: MCF-7 cells were treated with 1,25(OH)2D3 and their levels of VDR expression, viability, and apoptosis were detected. CD133+ MCF-7 stem cells were identified and transfected with a VDR-overexpression plasmid. The tamoxifen concentration that reduced MCF-7 cell viability by 50% (IC50) was determined. The activation of Wnt/ß-catenin signaling was also investigated. Results: Vitamin D reduced the viability of MCF-7 cells and promoted their apoptosis. Vitamin D enhanced VDR expression and induced DNA damage. When CD133+ stem cells were separated from MCF-7 cells, the IC50 of tamoxifen for stem cells was significantly higher than that of parental MCF-7 cells, suggesting a higher tamoxifen resistance in MCF-7 stem cells. Levels of VDR expression and Wnt/ß-catenin signaling in CD133+ cells were markedly lower and higher than those in CD133- cells, respectively. Stem cells transfected with VDR overexpression plasmids showed decreased tamoxifen IC50 values, viability, spheroid formation, and expression of Wnt and ß-catenin proteins when compared with control cells. Cell apoptosis was increased by transfection with a VDR overexpression plasmid. Finally, the inhibitory effects induced by VDR overexpression could be reversed by the VDR inhibitor, calcifediol. Conclusion: Stem cells contributed to the tamoxifen resistance of MCF-7 cells. Vitamin D-induced VDR expression increased the sensitivity of MCF-7 stem cells to tamoxifen by inhibiting Wnt/ß-catenin signaling.