Extracellular vesicles released by hypoxia-induced tumor-associated fibroblasts impart chemoresistance to breast cancer cells via long noncoding RNA H19 delivery.

Recently, extracellular vesicles (EVs) have been emphasized in regulating the hypoxic tumor microenvironment of breast cancer (BC), where tumor-associated fibroblasts (TAFs) play a significant role. In this study, we describe possible molecular mechanisms behind the pro-tumoral effects of EVs, secreted by hypoxia (HP)-induced TAFs, on BC cell growth, metastasis, and chemoresistance. These mechanisms are based on long noncoding RNA H19 (H19) identified by microarray analysis. We employed an in silico approach to identify differentially expressed lncRNAs that were associated with BC. Subsequently, we explored possible downstream regulatory mechanisms. We isolated EVs from TAFs that were exposed to HP, and these EVs were denoted as HP-TAF-EVs henceforth. MTT, transwell, flow cytometry, and TUNEL assays were performed to assess the malignant phenotypes of BC cells. A paclitaxel (TAX)-resistant BC cell line was constructed, and xenograft tumor and lung metastasis models were established in nude mice for in vivo verification. Our observation revealed that lncRNA H19 was significantly overexpressed, whereas miR-497 was notably downregulated in BC. HP induced activation of TAFs and stimulated the secretion of EVs. Coculture of HP-TAF-EVs and BC cells led to an increase in TAX resistance of the latter. HP-TAF-EVs upregulated methylation of miR-497 by delivering lncRNA H19, which recruited DNMT1, thus lowering the expression of miR-497. In addition, lncRNA H19-containing HP-TAF-EVs hindered miR-497 expression, enhancing tumorigenesis and TAX resistance of BC cells in vivo. Our study presents evidence for the contribution of lncRNA H19-containing HP-TAF-EVs in the reduction of miR-497 expression through the recruitment of DNMT1, which in turn promotes the growth, metastasis, and chemoresistance of BC cells.

Preoperative Nutritional Status of Infants with Non-Restricted Ventricular Septal Defect and Its Influence on Postoperative Recovery.

PURPOSE: This study described the preoperative nutritional status of infants with nonrestricted ventricular septal defects (VSDs) and evaluated its effect on postoperative recovery. METHODS: We retrospectively collected data from infants with nonrestricted VSD who received surgical treatment in our hospital from January 2020 to December 2021 and analyzed their preoperative nutritional status and postoperative recovery. RESULTS: Fifty (53.8%) patients were underweight (weight for age Z score (WAZ) ≤-1), and 31 (33.3%) patients were malnourished (WAZ ≤-2). The mechanical ventilation time, duration of intensive care unit stay and hospital stay time after surgery of patients with WAZ ≤-2 were significantly longer than those of patients with WAZ >-2 (p < 0.05). The results of linear correlation analysis showed that age, WAZ and prealbumin were negatively correlated with mechanical ventilation time, duration of intensive care unit stay and hospital stay time after surgery, respectively. Multiple linear regression analysis showed that mechanical ventilation time = 7.080 - 0.668 WAZ - 0.013 prealbumin - 0.618 age (R2: 0.729, F: 79.773, p: 0.001); duration of intensive care unit admission = 11.775 - 1.385 WAZ - 0.018 prealbumin - 0.102 age (R2: 0.714, F: 74.072, p: 0.001); and hospital stay time = 17.663 - 1.673 WAZ - 0.017 prealbumin - 1.07 age (R2: 0.711, F: 72.842, p: 0.001). CONCLUSION: The incidence of malnutrition in infants with nonrestricted VSD was very high, and malnutrition had a significant adverse effect on postoperative recovery. Malnutrition significantly prolonged mechanical ventilation time, duration of intensive care unit stay and hospital stay after surgery.