Effects of HER Family–targeting Tyrosine Kinase Inhibitors on Antibody-dependent Cell-mediated Cytotoxicity in HER2-expressing Breast Cancer

Abstract

Purpose: Antibody-dependent cell-mediated cytotoxicity (ADCC) is one mechanism of action of the monoclonal antibody (mAb) therapies trastuzumab and pertuzumab. Tyrosine kinase inhibitors (TKIs), like lapatinib, may have added therapeutic value in combination with mAbs through enhanced ADCC activity. Using clinical data, we examined the impact of lapatinib on HER2/EGFR expression levels and natural killer (NK) cell gene signatures. We investigated the ability of three TKIs (lapatinib, afatinib, and neratinib) to alter HER2/immune-related protein levels in preclinical models of HER2-positive (HER2+) and HER2-low breast cancer, and the subsequent effects on trastuzumab/pertuzumab-mediated ADCC. Experimental Design: Preclinical studies (proliferation assays, Western blotting, high content analysis, and flow cytometry) employed HER2+ (SKBR3 and HCC1954) and HER2-low (MCF-7, T47D, CAMA-1, and CAL-51) breast cancer cell lines. NCT00524303 provided reverse phase protein array–determined protein levels of HER2/pHER2/EGFR/pEGFR. RNA-based NK cell gene signatures (CIBERSORT/MCP-counter) post-neoadjuvant anti-HER2 therapy were assessed (NCT00769470/NCT01485926). ADCC assays utilized flow cytometry–based protocols. Results: Lapatinib significantly increased membrane HER2 levels, while afatinib and neratinib significantly decreased levels in all preclinical models. Single-agent lapatinib increased HER2 or EGFR levels in 10 of 11 (91%) tumor samples. NK cell signatures increased posttherapy (P = 0.03) and associated with trastuzumab response (P = 0.01). TKI treatment altered mAb-induced NK cell–mediated ADCC in vitro, but it did not consistently correlate with HER2 expression in HER2+ or HER2-low models. The ADCC response to trastuzumab and pertuzumab combined did not exceed either mAb alone. Conclusions: TKIs differentially alter tumor cell phenotype which can impact NK cell–mediated response to coadministered antibody therapies. mAb-induced ADCC response is relevant when rationalizing combinations for clinical investigation.

Neratinib plus trastuzumab is superior to pertuzumab plus trastuzumab in HER2-positive breast cancer xenograft models

“…Further, a substantial inhibition in the total EGFR, HER2, and HER3 levels was observed with neratinib, both alone and even more so in combination with trastuzumab. Our findings are in line with recent preclinical reports showing downregulation of total HER receptor levels in HER2-positive cell models treated with neratinib 32 , 33 . In contrast, with lapatinib alone, the phospho and total HER3 levels were either marginally increased or remained unaffected, potentially suggesting the feedback upregulation of HER3 levels following lapatinib treatment 8 , 34 .…”

The Prognostic Impact of HER2 Genetic and Protein Expression in Pancreatic Carcinoma—HER2 Protein and Gene in Pancreatic Cancer

“…However, what would need to be considered is that trastuzumab has several suppression mechanisms of HER2-dependent cell proliferation such as inhibiting HER2-receptor dimerization, preventing the sloughing of the extracellular domain, and immune activation [40]. Upon an immune reaction, some studies demonstrated that breast cancer cells with HER2 low levels resulted in initiating an immune response to breast cancer through the HER2 receptor, and the HER2 protein level was not the only factor indicating the drug response [41,42]. Nevertheless, a further study is required to clarify the mechanism of reaction in cancer with HER2 low expression.…”

A CIBERSORTx-based immune cell scoring system could independently predict the prognosis of patients with myelodysplastic syndromes

“…It has been shown to outperform other methods in estimating the relative proportion of closely related cell types in bulk tumors without physical cell sorting 12,13 . While the utility of CIBERSORT and CIBERSORTx has been validated in multiple tumor types [14][15][16][17] , their applicability in hematological malignancies remains scarce. A study demonstrated higher fraction of M2 macrophage as a predictor of inferior event-free survival (EFS) and overall survival (OS) in patients with acute myeloid leukemia (AML), and identified the macrophage marker CD206 as a novel prognostic indicator in these patients 18 .…”