Fig. 7: miR-142-3p regulates HIF1A/LOX/ITGA5 axis to confer chemosensitization in TNBC.

a Venn diagram of combinatorial target prediction analysis. Number of miRNAs targeting HIF1A (blue), LOX (green) and ITGA5 (orange) is shown. Eight miRNAs predicted to target all three genes are shown. b Heatmap showing Pearson’s correlation coefficients between miR-142-3p and HIF1A gene signature score, LOX and ITGA5 mRNA expressions in patients from GSE19783. An intense blue color shows a stronger negative correlation. c Kaplan–Meier survival curve in chemotherapy-treated TNBC patients (n = 106) based on low vs. high (median) miR-142-3p expression. d Table summarizing the association of miR-142-3p expression with survival in different breast cancer subtypes with or without chemotherapy. e, f qRT-PCR analyses of miR-142-3p expression in doxorubicin-sensitive (n = 11) vs. doxorubicin-resistant (n = 12) xenografts (e) and in MDA-MB-231 cells under hypoxia for 4 h (n = 3) (f). g. qRT-PCR of miR-142-3p upon transfection with two different siRNAs targeting HIF1A for 48 h (n = 3). h, i qRT-PCR (n = 3) (h) and western blot (i) analyses of HIF/LOX/ITGA5 axis upon miR-142-3p transfection. j. Western blot analyses of the HIF1A/LOX/ITGA5 axis in MDA-MB-231 xenografts stably expressing miR-142-3p. k Graphical representation of miR-142-3p binding sites within the 3′-UTRs of HIF1A, LOX and ITGA5. l. Luciferase reporter assay with 3′-UTRs of HIF1A, LOX or ITGA5 in MDA-MB-231 cells transfected with miR-Negative or miR-142-3p (n = 4 (HIF1A and LOX), n = 3–4 for (ITGA5)). m Percentage growth inhibition in collagen-embedded MDA-MB-231 cells after transfection with miR-142-3p in the presence or absence of doxorubicin (n = 4). n Immunofluorescence staining of Cleaved Caspase-3 (red) and F-actin (green) in miR-Negative or miR-142-3p transfected MDA-MB-231 cells in the presence or absence of doxorubicin. o. Quantification of Cleaved Caspase-3 positive cells from n. p. Western blot of cleaved PARP upon miR-142-3p transfection with or without doxorubicin treatment for 72 h. Data represents mean ± SD. Two-sided Student’s t-test was used to calculate statistical difference between two groups. One-way ANOVA with Dunnett’s test was performed to compare mean of combination-treated group with single agent treatments in m. Significance for survival analyses was calculated by log-rank (Mantel-Cox) test. HR hazard ratio. Scale bar = 50 µm for n. Source data are provided as a Source data file.