T-DM1-resistant cells gain high invasive activity via EGFR and integrin cooperated pathways

Abstract

Ado-trastuzumab emtansine (Kadcyla®; T-DM1) is an antibody-drug conjugate developed to treat trastuzumab-resistant disease. Despite initial favorable outcomes, most patients eventually cease to respond due to developing acquired resistance to T-DM1. Currently, there is no targeted therapy to treat T-DM1-resistant disease. To explore novel therapeutic targets to improve therapeutic efficacy of T-DM1, we generated T-DM1-resistant cells using trastuzumab-resistant JIMT1 cells. We found that the loss of human epidermal growth factor receptor 2 confers T-DM1 resistance, which in turn activates a compensatory mechanism that increases epidermal growth factor receptor (EGFR) expression. Upregulation of EGFR increases the protein levels of α5β1 and αVβ3 integrins, resulting in enhanced motility and invasion of T-DM1-resistant cells. This study delineates previously unappreciated relationships between α5β1 and αVβ3 and suggests that specific integrins should be carefully selected as therapeutic targets to treat T-DM1-resistant disease. Specifically, silencing β1 integrin expression by siRNA in T-DM1-resistant cells destabilizes α5, but increases expression of αV, a critical integrin mediating the invasion and metastases in many different cancers. As a consequence, T-DM1-resistant cells gain metastatic potential and become more invasive. This finding is underscored by the fact that β1 integrin blockage induced by an inhibitory antibody, MAB 13, significantly increases invasion of T-DM1-resistant cells. However, the increased cell invasion induced by β1 integrin blockage can be significantly reduced by either EGFR inhibitor or specific siRNA against αV integrin. The discovery of functional cooperation between EGFR and αV integrin in regulating cell growth and invasion provides an opportunity to develop novel therapeutic strategy by dual-targeting EGFR and specific integrin to overcome T-DM1 resistance.

Combination efficacy of pertuzumab and trastuzumab for trastuzumab emtansine-resistant cells exhibiting attenuated lysosomal trafficking or efflux pumps upregulation

“…1 c, d) (consistent with findings in Ref. [ 20 , 21 ] for BT-474). HER2 downstream signaling in OE19bTDR and BT-474bTDR was also equivalent to that in the parental cells (Fig.…”

“…As third-line therapy, the continuous use of a HER-targeting drug, such as TRAS or lapatinib, with chemotherapy has been reported to prolong progression-free survival in patients [16,17]; however, data on the selection of anti-HER2 drugs in patients with T-DM1 resistance are lacking and require clarification. Recently, several possible mechanisms of T-DM1 resistance have been reported: (1) reduced binding of T-DM1 to HER2 by HER2 downregulation [18] or by mucin 4 (MUC4) [19]; (2) attenuation of AKT signal inhibition caused by phosphatase and tensin homolog (PTEN) loss [20]; (3) signaling via the EGFR [21]; (4) overexpression of adenosine triphosphate (ATP)-binding cassette (ABC) transporters that are involved in multidrug resistance [18,20,22]; (5) downregulation of the lysosomal transporter solute carrier family 46 member 2 (SLC46A2) [20,23], lysosomal metabolic disorders [24,25], or abnormal lysosomal trafficking [26]; or (6) altered microtubule dynamics through a mutation in tubulin or altered activation of mitotic regulators [27,28]. Except for (1)-(3), these resistance mechanisms are specific to T-DM1 and not to TRAS or PER.…”

ARX788, a novel anti-HER2 antibody-drug conjugate, shows anti-tumor effects in preclinical models of trastuzumab emtansine-resistant HER2-positive breast cancer and gastric cancer

“…In addition, the T-DM1-resistant RN-87 and ROE-19 cells have higher ABC transporter expression than the sensitive N-87 and OE-19 cells [19]. A complete loss of HER2 expression caused acquired T-DM1-resistance in an in vitro model using JIMT-1 breast cancer cells [26]. Here we report retained expression of HER2 in T-DM1-resistant JIMT-1 xenografts.…”

Atezolizumab potentiates Tcell-mediated cytotoxicity and coordinates with FAK to suppress cell invasion and motility in PD-L1+triple negative breast cancer cells

“…Cell invasion assay kit was obtained from Millipore (cat#ECM554) and assay was executed according to manufacturer's instructions as described previously. 38 The assay kit contains invasion chamber or inserts with 8 µm pore size polycarbonate membrane and coated with thin layer of ECMatrix. Briefly, MDA-MB-231 and BT-20 cells were trypsinized and cell suspension was pre-incubated with ATE, FAK inhibitor (PF), ATE + PF or left untreated for 30 min at 37°C.…”