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Upregulation of ER Signaling as an Adaptive Mechanism of Cell Survival in HER2-Positive Breast Tumors Treated with Anti-HER2 Therapy.

ABSTRACT: To investigate the direct effect and therapeutic consequences of epidermal growth factor receptor 2 (HER2)-targeting therapy on expression of estrogen receptor (ER) and Bcl2 in preclinical models and clinical tumor samples.Archived xenograft tumors from two preclinical models (UACC812 and MCF7/HER2-18) treated with ER and HER2-targeting therapies and also HER2+ clinical breast cancer specimens collected in a lapatinib neoadjuvant trial (baseline and week 2 posttreatment) were used. Expression levels of ER and Bcl2 were evaluated by immunohistochemistry and Western blot analysis. The effects of Bcl2 and ER inhibition, by ABT-737 and fulvestrant, respectively, were tested in parental versus lapatinib-resistant UACC812 cells in vitro.Expression of ER and Bcl2 was significantly increased in xenograft tumors with acquired resistance to anti-HER2 therapy compared with untreated tumors in both preclinical models (UACC812: ER P = 0.0014; Bcl2 P < 0.001 and MCF7/HER2-18: ER P = 0.0007; Bcl2 P = 0.0306). In the neoadjuvant clinical study, lapatinib treatment for 2 weeks was associated with parallel upregulation of ER and Bcl2 (Spearman coefficient: 0.70; P = 0.0002). Importantly, 18% of tumors originally ER-negative (ER(-)) converted to ER(+) upon anti-HER2 therapy. In ER(-)/HER2(+) MCF7/HER2-18 xenografts, ER reexpression was primarily observed in tumors responding to potent combination of anti-HER2 drugs. Estrogen deprivation added to this anti-HER2 regimen significantly delayed tumor progression (P = 0.018). In the UACC812 cells, fulvestrant, but not ABT-737, was able to completely inhibit anti-HER2-resistant growth (P < 0.0001).HER2 inhibition can enhance or restore ER expression with parallel Bcl2 upregulation, representing an ER-dependent survival mechanism potentially leading to anti-HER2 resistance.

SUBMITTER: Giuliano M

PROVIDER: S-EPMC4558260 | biostudies-literature | 2015 Sep

REPOSITORIES: biostudies-literature

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Upregulation of ER Signaling as an Adaptive Mechanism of Cell Survival in HER2-Positive Breast Tumors Treated with Anti-HER2 Therapy.

Giuliano Mario M Hu Huizhong H Wang Yen-Chao YC Fu Xiaoyong X Nardone Agostina A Herrera Sabrina S Mao Sufeng S Contreras Alejandro A Gutierrez Carolina C Wang Tao T Hilsenbeck Susan G SG De Angelis Carmine C Wang Nicholas J NJ Heiser Laura M LM Gray Joe W JW Lopez-Tarruella Sara S Pavlick Anne C AC Trivedi Meghana V MV Chamness Gary C GC Chang Jenny C JC Osborne C Kent CK Rimawi Mothaffar F MF Schiff Rachel R

Clinical cancer research : an official journal of the American Association for Cancer Research 20150526 17

<h4>Purpose</h4>To investigate the direct effect and therapeutic consequences of epidermal growth factor receptor 2 (HER2)-targeting therapy on expression of estrogen receptor (ER) and Bcl2 in preclinical models and clinical tumor samples.<h4>Experimental design</h4>Archived xenograft tumors from two preclinical models (UACC812 and MCF7/HER2-18) treated with ER and HER2-targeting therapies and also HER2+ clinical breast cancer specimens collected in a lapatinib neoadjuvant trial (baseline and we ...[more]

PMID: 26015514

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Project description:BackgroundER+HER2+ breast cancer requires most types of systemic therapies perioperatively. However, treatment resistance is often experienced. The current study investigated the predictive and prognostic value of intratumoral heterogeneity and conventional clinicopathological factors in patients with ER+HER2+ breast cancer.MethodsThis research included two patient cohorts with ER+HER2+ breast cancer. Cohort A included patients who underwent surgery without neoadjuvant chemotherapy (NAC). Cohort B comprised patients who received NAC followed by surgery. Intratumoral heterogeneity was assessed via ER and HER2 double staining, and the number of cells stained with different patterns of ER and HER2 was counted.ResultsIn total, 11 of 92 tumors in cohort A and four of 45 tumors in cohort B consisted exclusively of double-positive (ER+ and HER2+) cells (homogeneous). The rest had different combinations of cells (heterogeneous). The pathological complete response (pCR) rates differed based on tumoral cell components but not intratumoral heterogeneity. The pCR rate of tumors with ER-HER2+ cells but without HER2- cells was higher than that of others (45.5% vs 4.3%; p = 0.0013). Low ER and PgR Allred scores indicated better pCR rates than high scores (p = 0.0005 and 0.024, respectively). Multivariate analysis showed that the ER Allred score and cell component of ER-HER2+ cells without HER2- cells were independent predictors of pCR (p = 0.0055 and 0.0081, respectively). In cohort B, posttreatment Ki67, but not pCR, was a prognostic factor of DFS and OS (p = 0.028 and 0.017, respectively). The prognostic value of combined posttreatment Ki67 and pCR was superior to that of either alone. Combined pCR and posttreatment Ki67 had an independent prognostic value for DFS and OS (p = 0.0068 and 0.0101, respectively).ConclusionsIn ER+HER2+ breast cancer, the presence of ER-HER2+ cells without HER2- cells was independently associated with pCR. Combined posttreatment Ki67 and pCR can be more precise in predicting prognosis than pCR alone.

Project description:Background:In premenopausal patients with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer, the gonadotoxicity of trastuzumab and lapatinib remains largely uncertain, and the prognostic effect of treatment-related amenorrhea (TRA) is unknown. Methods:In the Adjuvant Lapatinib and/or Trastuzumab Treatment Optimization (BIG 2-06) phase III trial, HER2-positive early breast cancer patients were randomized (1:1:1:1) to receive one year of trastuzumab, lapatinib, their sequence, or their combination. As per study protocol, menopausal status was collected in all patients at random assignment and at week 37 visit. We investigated TRA rates and whether TRA in patients with hormone receptor-positive and -negative tumors would impact disease-free survival (DFS) and overall survival (OS). Landmark and time-dependent modeling were used to account for guarantee-time bias. All statistical tests were two-sided. Results:A total of 2862 premenopausal women were included, of whom 1679 (58.7%) had hormone receptor-positive disease. Median age was 43 (interquartile range = 38-47) years. Similar TRA rates were observed in the trastuzumab (72.6%), lapatinib (74.0%), trastuzumab?lapatinib (72.1%), and trastuzumab+lapatinib (74.8%) arms (P = .64). The association between TRA and survival outcomes differed according to hormone-receptor status (Pinteraction for DFS = .007; Pinteraction for OS = .003). For hormone receptor-positive patients, the TRA cohort had statistically significantly better DFS (adjusted hazard ratio [aHR] = 0.58, 95% confidence interval [CI] = 0.45 to 0.76) and OS (aHR = 0.63, 95% CI = 0.40 to 0.99) than the no TRA cohort. No difference was observed in hormone receptor-negative patients. Conclusions:In this unplanned analysis, no association between TRA rate and type of anti-HER2 treatment was observed. TRA was associated with statistically significant survival benefits in premenopausal hormone receptor-positive/HER2-positive early breast cancer patients.

Dataset Information

Upregulation of ER Signaling as an Adaptive Mechanism of Cell Survival in HER2-Positive Breast Tumors Treated with Anti-HER2 Therapy.

Publications

Upregulation of ER Signaling as an Adaptive Mechanism of Cell Survival in HER2-Positive Breast Tumors Treated with Anti-HER2 Therapy.

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