Loss of WAVE3 sensitizes triple-negative breast cancers to chemotherapeutics by inhibiting the STAT-HIF-1α-mediated angiogenesis

Abstract

Chemoresistance allows for disease to recur and ultimately causes the death of most breast cancer patients. This scenario is particularly relevant in patients harboring triple-negative breast cancer (TNBC) tumors for which there are no effective FDA-approved drugs. However, a recent study determined that TNBCs can be segregated into 6 genetically distinct subtypes that do in fact exhibit differential rates of pathological complete response (pCR) to standard-of-care chemotherapies. Of these, the mesenchymal and mesenchymal stem-like subtypes of TNBCs exhibit the lowest rates of pCR when treated with standard-of-care chemotherapies. WAVE3 is an actin-cytoskeleton remodeling protein, and recent studies have highlighted a potential role for WAVE3 in promoting tumor progression and metastasis in TNBC. However, whether WAVE3 activity is involved in the development of chemoresistance in TNBCs remains unclear. Here we show that loss of WAVE3 expression resensitizes human TNBC cells to doxorubicin and docetaxel, as measured by increased apoptosis and cell death. We also show that WAVE3 knockdown in the chemotherapy-treated TNBC cells results in inhibition of STAT1 phosphorylation, as well as a significant decrease in expression levels of its downstream effector HIF-1a. Since HIF-1a is a major activator of VEGF-A production, and therefore a stimulator of tumor angiogenesis, loss of HIF-1a in the WAVE3-knockdown cells resulted in the inhibition the chemotherapy-mediated VEGF-A secretion and the downstream activation of angiogenesis, a phenomenon that often accompanies chemoresistance. Our data identify a critical role of WAVE3 in sensitizing TNBC to chemotherapy by inhibiting the STAT1!HIF-1a!VEGF-A signaling axis, and support the possibility that WAVE3 inhibition may be a promising target for TNBC cancer therapy.

The WAVE3-YB1 interaction regulates cancer stem cells activity in breast cancer

“…We have previously reported on the effect of siRNA- and shRNA-mediated knockdown WAVE3 expression on cell migration and invasion in cancer cells [ 17 , 18 , 20 , 21 , 23 , 27 ]. However, the effect of complete loss of WAVE3 expression using CRISPR/Cas9 has never been reported before.…”

“…Recently, we observed aberrant WAVE3 expression to be associated with the development of chemoresistant phenotypes in TNBCs [ 23 , 27 ], a trait that is also commonly attributed to cancer stem cells (CSCs) [ 28 – 32 ]. Unfortunately, the molecular mechanisms operating in coupling chemoresistance of CSCs to aberrant WAVE3 activity remain to be fully elucidated.…”

miR-138–Mediated Regulation of KINDLIN-2 Expression Modulates Sensitivity to Chemotherapeutics

“…Subconfluent cell cultures were treated with either the diluent or docetaxel (5 nM) for 12 h, after which cells were detached by trypsinization and washed with Hank’s Balanced Salt Solution with Ca2+, Mg2+, and 0.1% BSA. Cells were processed for flow cytometry as previously described (15;16) and following the manufacturer (Roche In-Situ Cell Death Detection Kit, Fluorescein). Annexin V and propidium iodide was used to quantify apoptotic and dead cells, respectively (16).…”

“…Cells were processed for flow cytometry as previously described (15;16) and following the manufacturer (Roche In-Situ Cell Death Detection Kit, Fluorescein). Annexin V and propidium iodide was used to quantify apoptotic and dead cells, respectively (16). For the quantification of β1 and β3 integrin surface expression, we used PE mouse anti-human CD29 and FITC mouse anti-human CD61, and their respective PE and FITC mouse IgG controls (BD Pharmigen; Franklin Lakes), NJ.…”

“…We followed the standard procedures for Western blotting as previously described (10–12;15;16). Signals were quantified using the ImageJ software according to the parameters described in ImageJ user guide (http://rsbweb.nih.gov/ij/docs/guide/146.html).…”