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High-grade serous ovarian cancer (HGSOC) and ovarian clear cell carcinoma (CC), are biologically aggressive tumors endowed with the ability to rapidly metastasize to the abdominal cavity and distant organs. About 10% of HGSOC and 30% of CC demonstrate HER2 IHC 3 + receptor over-expression. We evaluated the efficacy of trastuzumab deruxtecan (T-DXd; DS-8201a), a novel HER2-targeting antibody-drug conjugate (ADC) to an ADC isotype control (CTL ADC) against multiple HGSOC and CC tumor models. Eleven ovarian cancer cell lines including a matched primary and metastatic cell line established from the same patient, were evaluated for HER2 expression by immunohistochemistry and flow cytometry, and gene amplification by fluorescence in situ hybridization assays. In vitro experiments demonstrated T-DXd to be significantly more effective against HER2 3 + HGSOC and CC cell lines when compared to CTL ADC (p < 0.0001). T-DXd induced efficient bystander killing of HER2 non-expressing tumor cells when admixed with HER2 3 + cells. In vivo activity of T-DXd was studied in HER2 IHC 3 + HGSOC and CC mouse xenograft models. We found T-DXd to be significantly more effective than CTL ADC against HER2 3 + HGSOC (KR(CH)31) and CC (OVA10) xenografts with a significant difference in tumor growth starting at day 8 (p = 0.0003 for KR(CH)31, p < 0.0001 for OVA10). T-DXd also conferred a survival advantage in both xenograft models. T-DXd may represent an effective ADC against primary and metastatic HER2-overexpressing HGSOC and CC., (© 2024. The Author(s), under exclusive licence to Springer Nature B.V.)

Objective: Uterine serous carcinoma (USC) is an aggressive histologic variant of endometrial cancer which portends a poor prognosis. DHES0815A is a novel antibody-drug-conjugate (ADC) which binds specifically to HER2 overexpressing tumors at a distinct epitope from that bound by trastuzumab and pertuzumab after which it delivers the toxic payload, PBD-MA, a DNA mono-alkylating agent. The objective of this study was to evaluate the preclinical activity of DHES0815A against primary USC cell lines and xenografts., Methods: Twelve primary USC cell lines were assessed by immunohistochemistry (IHC) for HER2 protein expression and for C-erbB2 gene amplification using fluorescent in situ hybridization (FISH) analysis. Cell viability and bystander killing in USC cell lines after exposure to DHES0815A, the non-targeted ADC, and the unconjugated antibody (i.e. MHES0488A) were evaluated using flow cytometry-based-assays. In vivo activity of DHES0815A was tested against HER2/neu overexpressing USC xenografts., Results: High HER2/neu protein expression was seen in 25% (3/12) of the primary USC cell lines. USC cell lines overexpressing HER2/neu were significantly more sensitive to DHES0815A when compared to the non-targeted control ADC (p < 0.001). DHES0815A did not induce significant bystander killing of HER2/neu negative tumors when admixed with HER2/neu positive tumors. DHES0815A caused growth-inhibition and increased survival in USC HER2/neu overexpressing xenografts when compared to controls (p < 0.01)., Conclusions: DHES0815A is both highly selective and toxic to USC tumors overexpressing HER2/neu both in vitro and in vivo. HER2-directed ADCs, alone or in combination with other HER2/neu targeted agents may represent a novel treatment option for patients with tumors harboring HER2/neu overexpression refractory to trastuzumab and traditional chemotherapy., Competing Interests: Declaration of Competing Interest All authors fulfill the conditions required for authorship. Dr. Santin reports grants from PUMA, grants from IMMUNOMEDICS, grants from GILEAD, grants from SYNTHON, grants from MERCK, grants from BOEHINGER-INGELHEIM, grants from GENENTECH, grants from TESARO, during the conduct of the study. A.M. declares that she receives research-funding support from Spanish Medical Oncology Society. D.A.S reports Intuitive Surgical, Medtronic, Olympus, and Zai Lab consultant/speaker fees., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Objective: Due to previously reported trastuzumab safety concerns and the scant data available in endometrial cancer patients, we sought to assess the safety, tolerability and toxicity profile of trastuzumab in patients with advanced/recurrent uterine serous carcinoma (USC) that overexpress HER2/neu in our multicenter randomized phase II trial., Methods: Patients were randomized 1:1 to receive carboplatin/paclitaxel (C/P) for 6 cycles ± trastuzumab (T) with the experimental arm continuing to receive single agent trastuzumab maintenance treatment until disease progression/toxicity. Progression-free-survival was the primary endpoint; overall-survival and toxicity were secondary endpoints. Adverse events (AEs) were compared between treatment arms., Results: There were 28 patients in the C/P arm and 32 patients in the experimental (C/P + T) arm. Fifty-eight patients (97%) experienced 977 treatment-related AEs of which 875 (89.6%) were low-grade (grade 1-2) and 102 (10.4%) were high-grade (grade 3-5). The mean ± standard deviation of AEs per patient was 15.5 ± 16.3 in the C/P arm and 17.0 ± 16.0 in the C/P + T arm. Gastrointestinal AEs were the most common in both arms (n = 155, 15.7%) of which 94.2% were low-grade (n = 146). Importantly, no significant difference between treatment arms was detected in any system-organ class of AE including cardiac AE. Five (17%) of 29 patients who received prolonged trastuzumab maintenance therapy had no sign of cumulative toxicity after an average (range) of 5.1 (4.2-6.3) years., Conclusions: Trastuzumab appears to be safe and has a manageable toxicity profile both when used in combination with chemotherapy and when used for single agent maintenance in patients with HER2/neu positive USC. This safety profile is reassuring given the proven efficacy of trastuzumab in advanced/recurrent HER2/neu positive USC., Competing Interests: Declaration of Competing Interest All authors fulfill the conditions required for authorship., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The prognosis of advanced/recurrent cervical cancer patients remains poor. We analyzed 54 fresh-frozen and 15 primary cervical cancer cell lines, along with matched-normal DNA, by whole-exome sequencing (WES), most of which harboring Human-Papillomavirus-type-16/18. We found recurrent somatic missense mutations in 22 genes (including PIK3CA, ERBB2, and GNAS) and a widespread APOBEC cytidine deaminase mutagenesis pattern (TCW motif) in both adenocarcinoma (ACC) and squamous cell carcinomas (SCCs). Somatic copy number variants (CNVs) identified 12 copy number gains and 40 losses, occurring more often than expected by chance, with the most frequent events in pathways similar to those found from analysis of single nucleotide variants (SNVs), including the ERBB2/PI3K/AKT/mTOR, apoptosis, chromatin remodeling, and cell cycle. To validate specific SNVs as targets, we took advantage of primary cervical tumor cell lines and xenografts to preclinically evaluate the activity of pan-HER (afatinib and neratinib) and PIK3CA (copanlisib) inhibitors, alone and in combination, against tumors harboring alterations in the ERBB2/PI3K/AKT/mTOR pathway (71%). Tumors harboring ERBB2 (5.8%) domain mutations were significantly more sensitive to single agents afatinib or neratinib when compared to wild-type tumors in preclinical in vitro and in vivo models ( P = 0.001). In contrast, pan-HER and PIK3CA inhibitors demonstrated limited in vitro activity and were only transiently effective in controlling in vivo growth of PIK3CA-mutated cervical cancer xenografts. Importantly, combinations of copanlisib and neratinib were highly synergistic, inducing long-lasting regression of tumors harboring alterations in the ERBB2/PI3K/AKT/mTOR pathway. These findings define the genetic landscape of cervical cancer, suggesting that a large subset of cervical tumors might benefit from existing ERBB2/PIK3CA/AKT/mTOR-targeted drugs., Competing Interests: The authors declare no competing interest.

Purpose Uterine serous carcinoma is a rare, aggressive variant of endometrial cancer. Trastuzumab is a humanized monoclonal antibody that targets human epidermal growth factor receptor 2 (HER2)/neu, a receptor overexpressed in 30% of uterine serous carcinoma. This multicenter, randomized phase II trial compared carboplatin-paclitaxel with and without trastuzumab in patients with advanced or recurrent uterine serous carcinoma who overexpress HER2/neu. Methods Eligible patients had primary stage III or IV or recurrent HER2/neu-positive disease. Participants were randomly assigned to receive carboplatin-paclitaxel (control arm) for six cycles with or without intravenous trastuzumab (experimental arm) until progression or unacceptable toxicity. The primary end point was progression-free survival, which was assessed for differences between treatment arms via one-sided log-rank tests. Results From August 2011 to March 2017, 61 patients were randomly assigned. Forty progression-free survival-related events occurred among 58 evaluable participants. Among all patients, median progression-free survival was 8.0 months (control) versus 12.6 months (experimental; P = .005; hazard ratio [HR], 0.44; 90% CI, 0.26 to 0.76). Similarly, median progression-free survival was 9.3 (control) versus 17.9 (experimental) months among 41 patients with stage III or IV disease undergoing primary treatment ( P = .013; HR, 0.40; 90% CI, 0.20 to 0.80) and 6.0 (control) versus 9.2 months (experimental), respectively, among 17 patients with recurrent disease ( P = .003; HR, 0.14; 90% CI, 0.04 to 0.53). Toxicity was not different between treatment arms, and no unexpected safety signals emerged. Conclusion Addition of trastuzumab to carboplatin-paclitaxel was well tolerated and increased progression-free survival. These encouraging results deserve further investigation to determine their impact on overall survival in patients with advanced or recurrent uterine serous carcinoma who overexpress HER2/neu.

Purpose: Carcinosarcomas (CS) are highly aggressive gynecologic malignancies containing both carcinomatous and sarcomatous elements with heterogeneous HER2/neu expression. We compared the efficacy of SYD985 (Synthon Biopharmaceuticals BV), a novel HER2-targeting antibody-drug conjugate (ADC), to trastuzumab emtansine (T-DM1, Genentech-Roche) against primary uterine and ovarian CS. Experimental Design: Eight primary CS cell lines were evaluated for HER2/neu surface expression by IHC and gene amplification by FISH assays. The in vitro experiments included cytotoxicity, antibody-dependent cellular cytotoxicity (ADCC), proliferation, viability, and bystander killing. In vivo activity was studied in mouse xenograft and patient-derived xenograft (PDX) models. Results: SYD985 and T-DM1 induced similar levels of ADCC against CS cell lines with low and high HER2/neu expression when challanged in the presence of effector cells. In contrast, SYD985 was 7- to 54-fold more potent than T-DM1 in the absence of effector cells. SYD985, unlike T-DM1, was active against CS demonstrating low or heterogeneous HER2/neu expression. Specifically, the mean IC 50 values were 0.060 μg/mL and 3.221 μg/mL ( P < 0.0001) against HER2/neu 0/1+ cell lines and 0.013 μg/mL and 0.096 μg/mL ( P < 0.0001) against HER2/neu 3+ cell lines for SYD985 versus T-DM1, respectively. Importantly, unlike T-DM1, SYD985 induced efficient bystander killing of HER2/neu 0/1+ tumor cells admixed with HER2/neu 3+ cells. In vivo studies confirmed that SYD985 is more active than T-DM1 in CS and highly effective against HER2/neu expressing xenografts and PDX. Conclusions: SYD985 may represent a novel and highly effective ADC against HER2-expressing CS. Clinical studies with SYD985 in patients harboring chemotherapy-resistant CS with low/moderate and high HER2 expression are warranted. Clin Cancer Res; 23(19); 5836-45. ©2017 AACR ., (©2017 American Association for Cancer Research.)

Background: Epithelial ovarian cancer (EOC) is an aggressive and heterogeneous disease. <10% of EOC demonstrate HER2/neu 3+ receptor over-expression. However, moderate to low (i.e., 2+ and 1+) HER2/neu expression is reported in up to 50% of EOC. The objective of this study was to compare the anti-tumor activity of SYD985, a novel HER2-targeting antibody-drug conjugate (ADC), to trastuzumab emtansine (T-DM1) in EOC models with differential HER2/neu expression., Methods: The cytotoxicity of SYD985 and T-DM1 was evaluated using ten primary EOC cell lines with 0/1+, 2+, and 3+ HER2/neu expression in antibody-dependent cellular cytotoxicity (ADCC), proliferation, viability and bystander killing experiments. Finally, the in vivo activity of SYD985 and T-DM1 was also studied in ovarian cancer xenografts., Results: SYD985 and T-DM1 induced similar ADCC in the presence of peripheral blood lymphocytes (PBL) against EOC cell lines with differential HER2/neu expression. In contrast, SYD985 was 3 to 42 fold more cytotoxic in the absence of PBL when compared to T-DM1 (p<0.0001). Unlike T-DM1, SYD985 induced efficient bystander killing of HER2/neu 0/1+ tumor cells when admixed with HER2/neu 3+ EOC cells. In vivo studies confirmed that SYD985 is significantly more active than T-DM1 against HER2/neu 3+ EOC xenografts., Conclusions: SYD985 is a novel ADC with remarkable activity against EOC with strong (3+) as well as moderate to low (i.e., 2+ and 1+) HER2/neu expression. SYD985 is more potent than T-DM1 in comparative experiments and unlike T-DM1, it is active against EOC demonstrating moderate/low or heterogeneous HER2/neu expression., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Epithelial ovarian carcinoma is the most lethal of gynecologic malignancies. There is a need to optimize the currently available treatment strategies and to urgently develop novel therapeutic agents against chemotherapy-resistant disease. The objective of our study was to evaluate neratinib's preclinical efficacy in treating HER2-amplified ovarian cancer. Neratinib's efficacy in treating HER2-amplified ovarian cancer was studied in vitro utilizing six primary tumor cell lines with differential HER2/neu expression. Flow cytometry was utilized to assess IC 50 , cell signaling changes, and cell cycle distribution. Neratinib's in vivo efficacy was evaluated in HER2-amplified epithelial ovarian carcinoma xenografts. Three of six (50%) ovarian cancer cell lines were HER2/neu-amplified. Neratinib showed significantly higher efficacy in treating HER2/neu-amplified cell lines when compared to the non-HER2/neu-amplified tumor cell lines (mean ± SEM IC 50 :0.010 μM ± 0.0003 vs. 0.076 μM ± 0.005 p < 0.0001). Neratinib treatment significantly decreased the phosphorylation of the transcription factor S6, leading to arrest of the cell cycle in G0/G1 phase. Neratinib prolonged survival in mice harboring HER2-amplified epithelial ovarian carcinoma xenografts (p = 0.003). Neratinib inhibits proliferation, signaling, cell cycle progression and tumor growth of HER2-amplified epithelial ovarian carcinoma in vitro. Neratinib inhibits xenograft growth and improves overall survival in HER2/neu-amplified ovarian cancer in vivo. Clinical trials are warranted.

Uterine serous carcinoma (USC) is an aggressive form of endometrial cancer. Up to 35% of USC may overexpress the HER2/neu oncogene at strong (i.e., 3+) levels by IHC while an additional 40% to 50% express HER2/neu at moderate (2+) or low (1+) levels. We investigated the efficacy of SYD985, (Synthon Biopharmaceuticals), a novel HER2-targeting antibody-drug conjugate (ADC) composed of the mAb trastuzumab linked to a highly potent DNA-alkylating agent (i.e., duocarmycin) in USC. We also compared the antitumor activity of SYD985 in head-to-head experiments to trastuzumab emtansine (T-DM1), a FDA-approved ADC, against multiple primary USC cell lines expressing different levels of HER2/neu in in vitro and in vivo experiments. Using antibody-dependent cellular cytotoxicity (ADCC), proliferation, viability, and bystander killing assays as well as propidium iodide-based flow cytometry assays and multiple in vivo USC mouse xenograft models, we demonstrate for the first time that SYD985 is a novel ADC with activity against USC with strong (3+) as well as low to moderate (i.e., 1+/2+) HER2/neu expression. SYD985 is 10- to 70-fold more potent than T-DM1 in comparative experiments and, unlike T-DM1, it is active against USC demonstrating moderate/low or heterogeneous HER2/neu expression. Clinical studies with SYD985 in patients harboring chemotherapy-resistant USC with low, moderate, and high HER2 expression are warranted. Mol Cancer Ther; 15(8); 1900-9. ©2016 AACR., (©2016 American Association for Cancer Research.)

HER2/neu gene amplification and PIK3CA driver mutations are common in uterine serous carcinoma (USC) and may represent ideal therapeutic targets against this aggressive variant of endometrial cancer. We examined the sensitivity to neratinib, taselisib, and the combination of the two compounds in in vitro and in vivo experiments using PIK3CA-mutated and PIK3CA wild-type HER2/neu-amplified USC cell lines. Cell viability and cell-cycle distribution were assessed using flow-cytometry assays. Downstream signaling was assessed by immunoblotting. Preclinical efficacy of single versus dual inhibition was evaluated in vivo using two USC xenografts. We found both single-agent neratinib and taselisib to be active but only transiently effective in controlling the in vivo growth of USC xenografts harboring HER2/neu gene amplification with or without oncogenic PIK3CA mutations. In contrast, the combination of the two inhibitors caused a stronger and long-lasting growth inhibition in both USC xenografts when compared with single-agent therapy. Combined targeting of HER2 and PIK3CA was associated with a significant and dose-dependent increase in the percentage of cells in the G0-G1 phase of the cell cycle and a dose-dependent decline in the phosphorylation of S6. Importantly, dual inhibition therapy initiated after tumor progression in single-agent-treated mice was still remarkably effective at inducing tumor regression in both large PIK3CA and pan-ErbB inhibitor-resistant USC xenografts. Dual HER2/PIK3CA blockade may represent a novel therapeutic option for USC patients harboring tumors with HER2/neu gene amplification and mutated or wild-type PIK3CA resistant to chemotherapy., (©2015 American Association for Cancer Research.)

Objective: Carcinosarcoma is a deadly gynecologic malignancy with few effective treatment options. The study of new therapies is difficult because of its rarity. The objective of this study was to determine the efficacy of neratinib in the treatment of HER2 amplified carcinosarcoma., Methods: The efficacy of neratinib in the treatment of HER2 amplified carcinosarcoma was determined in vitro using seven primary carcinosarcoma cell lines with differential expression of HER2/neu. Data regarding IC50, cell cycle distribution, and cell signaling changes were assessed by flow cytometry. The efficacy of neratinib was determined in treating mice harboring HER2 amplified carcinosarcoma xenografts., Results: Two of seven (28.5%) carcinosarcoma cell lines were HER2/neu amplified. HER2/neu amplified cell lines SARARK6 and SARARK9 were significantly more sensitive to neratinib than the five non-HER2/neu amplified carcinosarcoma cell lines (mean±SEM IC50:0.014μM±0.004vs.0.164μM±0.019 p=0.0003). Neratinib treatment caused a significant build up in G0/G1 phase of the cell cycle, arrest auto phosphorylation of HER2/neu and activation of S6. Neratinib inhibited tumor growth (p=0.012) and prolonged survival in mice harboring HER2 amplified carcinosarcoma xenografts (p=0.0039)., Conclusions: Neratinib inhibits HER2 amplified carcinosarcoma proliferation, signaling, cell cycle progression and tumor growth in vitro. Neratinib inhibits HER2/neu amplified xenograft growth and improves overall survival. Clinical trials are warranted., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Objectives: We evaluated the role of PIK3CA-mutations as mechanism of resistance to trastuzumab in primary HER2/neu-amplified uterine-serous-carcinoma (USC) cell lines., Methods: Fifteen whole-exome-sequenced USC cell lines were tested for HER2/neu-amplification and PIK3CA-mutations. Four HER2/neu-amplified USC (2-harbouring wild-type-PIK3CA-genes and 2-harbouring oncogenic-PIK3CA-mutations) were evaluated in in vitro dose-titration-proliferation-assays, cell-viability and HER2 and S6-protein-phosphorylation after exposure to trastuzumab. USC harbouring wild-type-PIK3CA were transfected with plasmids encoding oncogenic PIK3CA-mutations (i.e., H1047R/R93Q) and exposed to trastuzumab. Finally, trastuzumab efficacy was tested by using two USC xenograft mouse models., Results: Seven out of fifteen (46%) of the USC cell lines were HER2/neu-amplified by fluorescence in situ hybridisation. Within these tumours four out of seven (57%) were found to harbour oncogenic PIK3CA-mutations vs two out of eight (25%) of the HER2/neu not amplified cell lines (P=0.01). HER2/neu-amplified/PIK3CA-mutated USC were highly resistant to trastuzumab when compared with HER2/neu-amplified/wild-type-PIK3CA cell lines (P=0.02). HER2/neu-amplified/PIK3CA wild-type cell lines transfected with oncogenic PIK3CA-mutations increased their resistance to trastuzumab (P<0.0001). Trastuzumab was effective in reducing tumour growth (P=0.001) and improved survival (P=0.0001) in mouse xenografts harbouring HER2-amplified/PIK3CA wild-type USC but not in HER2-amplified/PIK3CA-mutated tumours., Conclusions: Oncogenic PIK3CA mutations are common in HER2/neu-amplified USC and may constitute a major mechanism of resistance to trastuzumab treatment.

Uterine serous carcinoma (USC) is an aggressive subtype of endometrial cancer that carries an extremely poor prognosis. Up to 35 % of USC may overexpress the epidermal growth factor receptor-2 (HER2/neu) at strong (i.e., 3+) level by immunohistochemistry (IHC) or harbor HER2/neu gene amplification by fluorescence in situ hybridization (FISH). In this study, we assessed the sensitivity of a panel of USC cell lines with and without HER2/neu gene amplification to dacomitinib (PF-00299804), an irreversible pan-human epidermal growth factor receptor tyrosine kinase inhibitor. Eight primary cell lines (i.e., four harboring HER2/neu gene amplification by FISH and four FISH- cell lines), all demonstrating similar in vitro growth rates, were evaluated in viability/proliferation assays. The effect of dacomitinib on cell growth, cell cycle distribution, and signaling was determined using flow cytometry-based assays. Dacomitinib caused a significantly stronger growth inhibition in HER2/neu FISH+ USC cell lines when compared to FISH- USC (dacomitinib half maximal inhibitory concentration (IC50) mean ± SEM = 0.02803 ± 0.003355 μM in FISH+ versus 1.498 ± 0.2209 μM in FISH- tumors, P < 0.0001). Dacomitinib growth inhibition was associated with a significant and dose-dependent decline in phosphorylated HER2/neu and S6 transcription factor and a dose-dependent and time-dependent cell cycle arrest in G0/G1 in FISH+ USC. Dacomitinib is remarkably effective against chemotherapy-resistant HER2/neu gene-amplified USC. Clinical studies with dacomitinib in HER2/neu FISH+ USC patients resistant to standard salvage chemotherapy are warranted.

Objective: To evaluate the efficacy of taselisib, a selective inhibitor of PIK3CA, against primary uterine serous carcinomas (USC) harboring PIK3CA mutations and HER2/neu gene amplification., Methods: Sensitivity to taselisib was evaluated by flow-cytometry viability assays in vitro against nine primary USC cell lines. Cell cycle distribution and downstream signaling were assessed by measuring the DNA content of cells and by phosphorylation of the S6 protein by flow-cytometry. Preclinical efficacy of taselisib was also evaluated in vivo in a mouse model., Results: Four USC cell lines harbored HER2/neu gene amplification by FISH and two of them harbored oncogenic PIK3CA mutations. Taselisib caused a strong differential growth inhibition in both HER2/neu FISH positive and HER2/neu FISH positive/PIK3CA mutated USC cell lines when compared to lines that were FISH negative and PIK3CA wild type (taselisib IC50 mean±SEM=0.042±0.006μM in FISH+ versus 0.38±0.06μM in FISH-tumors, P<0.0001). Taselisib growth-inhibition was associated with a significant and dose-dependent increase in the percentage of cells in the G0/G1 phase of the cell cycle and dose-dependent decline in the phosphorylation of S6. Taselisib was highly active at reducing tumor growth in vivo in USC mouse xenografts harboring PIK3CA mutation and overexpressing HER2/neu (P=0.007). Mice treated with taselisib had significantly longer survival when compared to control mice (P<0.0001)., Conclusions: Taselisib represents a novel therapeutic option in patients harboring PIK3CA mutations and/or HER2/neu gene amplification., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Uterine serous carcinomas (USCs) are an aggressive form of uterine cancer that may rely on HER2/neu amplification as a driver of proliferation. The objective of this paper is to assess the sensitivity of USC cell lines with and without HER2/neu gene amplification to afatinib, an irreversible ErbB tyrosine kinase inhibitor, and to test the efficacy of afatinib in the treatment of HER2-amplified USC xenografts., Methods: Eight of fifteen primary USC cell lines (four with HER2 amplification and four without) demonstrating similar in vitro growth rates were treated with scalar concentrations of afatinib. Effects on cell growth, signalling and cell cycle distribution were determined by flow cytometry assays. Mice harbouring xenografts of HER2/neu-amplified USC were treated with afatinib by gavage to determine the effect on tumour growth and overall survival., Results: Primary chemotherapy-resistant USC cell lines harbouring HER2/neu gene amplification were exquisitely sensitive to afatinib exposure (mean ± s.e.m. IC50=0.0056 ± 0.0006 μM) and significantly more sensitive than HER2/neu-non-amplified USC cell lines (mean ± s.e.m. IC50=0.563 ± 0.092 μM, P<0.0001). Afatinib exposure resulted in abrogation of cell survival, inhibition of HER2/neu autophosphorylation and S6 transcription factor phosphorylation in HER2/neu overexpressing USC and inhibited the growth of HER2-amplified tumour xenografts improving overall survival (P=0.0017)., Conclusions: Afatinib may be highly effective against HER2/neu-amplified chemotherapy-resistant USC. The investigation of afatinib in patients harbouring HER2/neu-amplified USC is warranted.

Amplification of c-erbB2 has been reported in over 30% of uterine serous carcinoma (USC) and found to confer poor survival because of high proliferation and increased resistance to therapy. In this study, we evaluated for the first time Trastuzumab emtansine (T-DM1), a novel antibody-drug conjugate, against multiple epidermal growth factor receptor-2 (HER2)-positive USC cells in vitro followed by developing a supportive in vivo model. Fifteen primary USC cell lines were assessed by immunohistochemistry (IHC) and flow cytometry for HER2 protein expression. C-erbB2 gene amplification was evaluated using fluorescent in situ hybridization. Sensitivity to T-DM1 and trastuzumab (T)-induced antibody-dependent cell-mediated cytotoxicity was evaluated in 5-h chromium release assays. T-DM1 and T cytostatic and apoptotic activities were evaluated using flow-cytometry-based proliferation assays. In vivo activity of T-DM1 versus T in USC xenografts in SCID mice was also evaluated. High levels of HER2 protein overexpression and HER2 gene amplification were detected in 33% of USC cell lines. T-DM1 was considerably more effective than trastuzumab in inhibiting cell proliferation and in causing apoptosis (P = 0.004) of USC showing HER2 overexpression. Importantly, T-DM1 was highly active at reducing tumor formation in vivo in USC xenografts overexpressing HER2 (P = 0.04) and mice treated with TDM-1 had significantly longer survival when compared to T-treated mice and control mice (P ≤ 0.0001). T-DM1 shows promising antitumor effect in HER2-positive USC cell lines and USC xenografts and its activity is significantly higher when compared to T. T-DM1 may represent a novel treatment option for HER2-positive USC patients with disease refractory to trastuzumab and traditional chemotherapy., (© 2014 The Authors. Cancer Medicine published by John Wiley & Sons Ltd.)

Objectives: Uterine serous carcinoma (USC) represents an aggressive variant of endometrial cancer and accounts for a large proportion of deaths annually. HER2/neu amplification is associated with USC in approximately 30-35% of cases. The objective of this study was to determine the sensitivity of a panel of primary USC cell lines to the small tyrosine kinase inhibitor neratinib, an ErbB1 and HER2 inhibitor, both in vitro and in vivo., Methods: HER2/neu amplification was determined by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) in 24 USC cell lines. Flow cytometry was used to determine the effects of neratinib on cell viability, cell cycle distribution and signaling in vitro. Mice harboring HER2/neu amplified xenografts were treated with neratinib to assess the efficacy of the drug in vivo., Results: HER2/neu amplification was noted in 8/24 primary cell lines. Data regarding the efficacy of neratinib was determined using 4 HER2 amplified cell lines and 4 non-amplified cell lines with similar growth rates. Data revealed that cell lines with HER2/neu amplification were exquisitely more sensitive to neratinib compared to non-amplified cell lines (mean ± SEM IC50: 0.011μM ± 0.0008 vs. 0.312μM ± 0.0456 p<0.0001). Neratinib caused arrest in the G0/G1 phase of the cell cycle and resulted in decreased autophosphorylation of HER2 and activation of S6. Neratinib treated mice harboring xenografts of HER2/neu amplified USC showed delayed tumor growth and improved overall survival compared to vehicle (p=0.0019)., Conclusions: Neratinib may be a potential treatment option for patients harboring HER2/neu amplified USC. Clinical trials for this subset of endometrial cancer patients are warranted., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Objective: To evaluate c-erbB2 gene amplification in a series of primary uterine serous carcinoma (USC) cell lines. To assess the efficacy of AZD8055, a novel dual mTORC1/2 inhibitor against primary HER2/neu amplified vs HER2/neu not amplified USC cell lines., Methods: Twenty-two primary USC cell lines were evaluated for c-erbB2 oncogene amplification by FISH assays. In vitro sensitivity to AZD8055 was evaluated by flow-cytometry-based viability and proliferation assays. Cell cycle profile and downstream cellular responses to AZD8055 were assessed by measuring the DNA content of cells and by phosphorylation of the S6 protein by flow-cytometry., Results: Nine of 22 (40.9%) USC cell lines demonstrated c-erbB2 gene amplification by FISH. AZD8055 caused a strong differential growth inhibition in USC cell lines, with high HER-2/neu-expressors demonstrating significantly higher sensitivity when compared to low HER-2/neu-expressors (AZD-8055 IC50 mean±SEM=0.27±0.05μM in c-erbB2 amplified versus 1.67±0.68μM in c-erbB2 not amplified tumors, P=0.03). AZD8055 growth-inhibition was associated with a significant and dose-dependent increase in the percentage of cells blocked in the G0/G1 cell cycle phase and a dose-dependent decline in pS6 levels in both c-erbB2 amplified vs c-erbB2 not amplified USC cell lines., Conclusions: AZD8055 may represent a novel targeted therapeutic agent in patients harboring advanced/recurrent/refractory USC. c-erbB2 gene amplification may represent a biomarker to identify USC patients who may benefit most from the use of AZD8055., (© 2013.)

Carcinosarcomas of the female genital tract are rare tumors with an aggressive clinical behavior. Trastuzumab, a humanized monoclonal antibody, acts by binding to HER2/neu extracellular domain and exhibits therapeutic efficacy in HER2/neu-overexpressing cancers. Two uterine carcinosarcomas (UMMT-ARK-1, UMMT-ARK-2) and 2 ovarian carcinosarcomas (OMMT-ARK-1, OMMT-ARK-2) were established as primary tumor cell lines in vitro and evaluated for HER2/neu expression by immunohistochemistry, fluorescent in situ hybridization analysis, quantitative real-time polymerase chain reaction, and for membrane-bound complement regulatory proteins CD46, CD55, and CD59 by flow cytometry. Sensitivity to trastuzumab-dependent cell-mediated cytotoxicity (ADCC) and complement-dependent cytotoxicity was studied in 5-hr chromium release assays. HER2/neu expression was demonstrated in OMMT-ARK-1 and OMMT-ARK-2. OMMT-ARK-2 demonstrated an amplification of the c-erbB2 gene by fluorescent in situ hybridization analysis and a high sensitivity to ADCC (mean killing, 45.6%; range, 32.3%-72.6%). A lower level of killing was detected against the fluorescent in situ hybridization analysis-negative OMMT-ARK-1 cell line (mean, 26.5%; range, 21.0%-31.8%). CD46, CD55, and CD59 membrane-bound complement regulatory proteins were expressed at high levels in all primary mixed müllerian tumor cell lines, and all these tumors were found to be highly resistant to complement-dependent cytotoxicity with or without trastuzumab. Addition of untreated and heat-inactivated plasma did not significantly decrease ADCC against OMMT-ARK-2 cell line, suggesting that while the cell line is highly resistant to complement, irrelevant IgG does not significantly alter the ability of trastuzumab to mediate ADCC. Our results suggest that HER2/neu may represent a novel target for the immunotherapy of a subset of human carcinosarcomas refractory to salvage chemotherapy.

Background: We evaluated the expression of CD46, CD55 and CD59 membrane-bound complement-regulatory proteins (mCRPs) in primary uterine serous carcinoma (USC) and the ability of small interfering RNA (siRNA) against these mCRPs to sensitise USC to complement-dependent cytotoxicity (CDC) and antibody (trastuzumab)-dependent cellular cytotoxicity (ADCC) in vitro., Methods: Membrane-bound complement-regulatory proteins expression was evaluated using real-time PCR (RT-PCR) and flow cytometry, whereas Her2/neu expression and c-erbB2 gene amplification were assessed using immunohistochemistry, flow cytometry and fluorescent in-situ hybridisation. The biological effect of siRNA-mediated knockdown of mCRPs on HER2/neu-overexpressing USC cell lines was evaluated in CDC and ADCC 4-h chromium-release assays., Results: High expression of mCRPs was found in USC cell lines when compared with normal endometrial cells (P<0.05). RT-PCR and FACS analyses demonstrated that anti-mCRP siRNAs were effective in reducing CD46, CD55 and CD59 expression on USC (P<0.05). Baseline complement-dependent cytotoxicity (CDC) against USC cell lines was low (mean ± s.e.m.=6.8 ± 0.9%) but significantly increased upon CD55 and CD59 knockdown (11.6 ± 0.8% and 10.7 ± 0.9%, respectively, P<0.05). Importantly, in the absence of complement, both CD55 and CD59, but not CD46, knockdowns significantly augmented ADCC against USC overexpressing Her2/neu., Conclusion: Uterine serous carcinoma express high levels of the mCRPs CD46, CD55 and CD59. Small interfering RNA inhibition of CD55 and CD59, but not CD46, sensitises USC to both CDC and ADCC in vitro, and if specifically targeted to tumour cells, may significantly increase trastuzumab-mediated therapeutic effect in vivo.

Objective: To compare the in vitro sensitivity/resistance to patupilone versus paclitaxel in uterine serous papillary carcinoma (USPC) with high versus low HER-2/neu expression., Methods: Six primary USPC cell lines, half of which overexpress HER-2/neu at a 3+ level, were evaluated for growth rate and tested for their in vitro sensitivity/resistance to patupilone versus paclitaxel by MTS assays. Quantitative RT-PCR was used to identify potential mechanisms underlying the differential sensitivity/resistance to patupilone versus paclitaxel in primary USPC cell lines., Results: Cell lines overexpressing HER-2/neu showed higher proliferation when compared to low HER-2/neu-expressing cell lines. Compared to low-expressing cell lines, high HER-2/neu expressors were significantly more sensitive to patupilone than to paclitaxel (P<0.0002). In contrast, there was no appreciable difference in sensitivity to patupilone versus paclitaxel in primary USPC cell lines with low HER-2/neu expression. Higher levels of β-tubulin III (TUBB3) and P-glycoprotein (ABCB1) were detected in USPC cell lines with high versus low HER-2/neu expression (P<0.05)., Conclusions: USPC overexpressing HER-2/neu display greater in vitro sensitivity to patupilone and higher levels of the patupilone molecular target TUBB3 when compared to low HER-2/neu expressors. Due to the adverse prognosis associated with HER-2/neu overexpression in USPC patients, patupilone may represent a promising novel drug to combine to platinum compounds in this subset of aggressive endometrial tumors., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Objective: We sought to identify effective chemotherapy regimens against uterine serous papillary adenocarcinoma (USPC)., Study Design: Six USPC, half of which overexpress HER-2/neu at 3+ level, were evaluated for growth rate and in vitro sensitivity to 14 single-agent chemotherapies and 5 combinations by ChemoFx (Precision Therapeutics Inc, Pittsburgh, PA)., Results: Cell lines overexpressing HER-2/neu showed higher proliferation when compared to low HER-2/neu-expressing cell lines and a lower half maximum inhibitory concentration (IC(50)) when exposed to the majority of single-agent chemotherapies. High HER-2/neu expressors were more sensitive to platinum compounds, manifesting a 5.22-fold decrease in carboplatin-IC(50) (P = .005) and a 5.37-fold decrease in cisplatin-IC(50) (P = .02). When all cell lines were analyzed as a group, chemotherapy agents tested demonstrated lower IC(50) when used in combination than as individual agents., Conclusion: USPC overexpressing HER-2/neu display greater in vitro sensitivity to platinum compounds when compared to low HER-2/neu expressors. Higher proliferative capability rather than increased drug resistance may be responsible for the adverse prognosis associated with HER-2/neu overexpression in USPC., (Copyright (c) 2010 Mosby, Inc. All rights reserved.)

Objective: To study the effect of trastuzumab in patients with progressive or recurrent metastatic endometrial carcinoma shown by immunohistochemistry to overexpress the HER2/neu receptor., Methods: Disease progression was examined in 2 patients who met the study criteria, had c-erbB2 gene amplification by fluorescence in situ hybridization, and were treated with trastuzumab following radiation treatment and/or salvage chemotherapy., Results: The clinical responses to trastuzumab as a single agent or in combination with chemotherapy were confirmed in both patients by serial CT scans and serum CA-125 evaluations. These patients with progressive or recurrent metastatic disease experienced relief from their symptoms and prolonged survival with no significant toxicity observed., Conclusion: Trastuzumab may be a viable therapeutic option as single agent or in combination with chemotherapy in patients with advanced, recurrent, and/or metastatic endometrial carcinomas overexpressing HER2/neu.

Background: Overexpression of the epidermal growth factor type II receptor HER-2/neu has been associated with resistance to chemotherapy and poor survival in several human tumors. In the current study, the authors have determined the frequency and clinical significance of HER-2/neu gene amplification in uterine serous papillary endometrial carcinoma (USPC), a highly aggressive variant of endometrial carcinoma., Methods: Fluorescence in situ hybridization (FISH) assay was used to analyze gene amplification in paraffin blocks from 30 women harboring Stage IA-IV USPC treated at the University of Arkansas for Medical Sciences (Little Rock, AR) from 1997 to 2004. Chromosome 17 polysomy status by FISH was also assessed in all specimens. USPC patient survival in relation to HER-2/neu gene amplification was analyzed using Kaplan-Meier curves in conjunction with the log-rank test., Results: Amplification of the HER-2/neu gene by FISH was observed in 14 of the 30 (47%) cases. Heterogeneity was noted in 4 of 14 cases in the amplification of the HER-2/neu gene within the same tumor samples with pockets of amplified tumor cells amidst nonamplified tumor cells. Patients with USPC harboring tumors with HER-2/neu gene amplification had a significantly shorter survival time from diagnosis to disease-related death when compared with FISH-negative patients (P = 0.0008). African-American (AA) patients were found to have a poorer prognosis compared with Caucasian (C) women (P = 0.01) and to harbor USPC with significantly higher levels of HER-2/neu gene amplification (P = 0.02)., Conclusions: HER-2/neu gene amplification in USPC was found to be an important prognostic indicator for poor outcome that occurs more frequently in AA when compared with C patients. Determination of HER-2/neu gene amplification may guide clinical management of patients with USPC and may have important implications for the implementation of novel treatment strategies.

Objective: To evaluate and compare HER2/neu protein overexpression and gene amplification in uterine serous papillary endometrial cancer (USPC)., Study Design: Immunohistochemical (IHC) and fluorescent in situ hybridization (FISH) assays were used to analyze and compare HER2/neu protein expression and gene amplification, respectively, in paraffin blocks from 26 women harboring stage IA to IV USPC treated at the University of Arkansas for Medical Sciences from 1997 to 2004. Chromosome 17 polysomy status by FISH was also assessed in all specimens., Results: Moderate-to-strong expression of HER2/neu protein was noted in 16 (62%) of 26 USPC samples evaluated, with 7 (27%) samples showing moderate staining (2+) and 9 (35%) showing strong staining (3+) for HER2/neu. Amplification of the ERBB2 gene by FISH was observed in 11 of the 26 (42%) cases. Protein overexpression and gene amplification were found to correlate in 100% (9 of 9) of the 3+ positive tumors and 2 out of 7 (29%) of the 2+ positive tumors. Heterogeneity was noted in 3 cases in the amplification of the HER2/neu gene within the same tumor samples with pockets of amplified tumor cells amidst nonamplified tumor cells. None of the 10 USPC cases scored by IHC as 0 or 1+ was found positive for ERBB2 amplification by FISH., Conclusions: Amplification of the HER2/neu oncogene represents a common finding in USPC. FISH analysis should be used for confirmation of gene amplification in USPC showing 2+ expression of HER2/neu. Prior screening and selection of appropriate immunohistochemistry-positive areas may be beneficial in the selection of some USPC patients undergoing FISH analysis.

Objective: The purpose of this study was to compare HER-2/neu expression on biopsies obtained from early stage cervical cancer, primary cell lines established therefrom, established cervical cancer cell lines, and metastatic or recurrent sites of disease; and to evaluate the sensitivity of primary cervical cancer cell lines to treatment with a humanized MAb against HER-2/neu (Herceptin)., Methods: Surface HER-2/neu expression on 18 cervical cancer cell lines was compared to HER-2/neu detection by immunohistochemistry on biopsies obtained from the original tumors (10 patients) and sites of recurrence (2 patients). Primary cell lines were tested for sensitivity to Herceptin-mediated antibody-dependent cellular cytotoxicity (ADCC) and sensitivity to Herceptin-mediated inhibition of proliferation., Results: Nine out of 10 primary (90%) and 8 out of 8 (100%) established cervical cancer cell lines expressed HER-2/neu by flow cytometry. Surprisingly, all HER-2/neu-positive primary cell lines were derived from tumor biopsies that scored negative (i.e., 0 to 1+) for HER-2/neu expression by immunohistochemistry. Heavy staining for HER-2/neu (i.e., 3+) was found in the recurrent/metastatic lesions of the two relapsed patients. Importantly, all HER-2/neu-positive primary cell lines were highly sensitive to Herceptin-mediated ADCC, and their proliferation was also significantly inhibited by Herceptin. A significant enhancement of Herceptin-mediated ADCC was demonstrated when effector cells were exposed to low doses of IL-2 in vitro., Conclusions: Early stage cervical cancer may develop a population of HER-2/neu-positive cells with a selective growth advantage over HER-2/neu-negative cells. Therapy which targets HER-2/neu may be more effective in patients with cervical cancer than indicated by the commonly low expression of HER-2/neu in tumors removed at the time of primary treatment.

Purpose: Uterine serous papillary carcinoma (USPC) is a highly aggressive variant of endometrial cancer and histologically similar to high-grade ovarian cancer. HER-2/neu, the transmembrane receptor encoded by the c-erbB2 gene, is overexpressed by immunohistology in approximately 25% of ovarian cancers. In this study, we have evaluated the expression of HER-2/neu in several fresh, established, paraffin-embedded, fixed USPCs. In addition, we have tested the sensitivity of USPC cells to Herceptin treatment., Experimental Design: Ten consecutive USPC specimens were assessed by immunohistochemistry for the intensity of expression of HER-2/neu. In addition, three USPC cell lines were analyzed for expression of HER-2/neu by flow cytometry as well as for sensitivity to Herceptin-mediated, complement-dependent cytotoxicity, antibody-dependent cellular cytotoxicity (ADCC), and inhibition of cell proliferation., Results: Eight of 10 (80%) of the USPCs assessed immunohistochemically for the intensity of expression of HER-2/neu stained heavily for HER-2/neu (2+ to 3+). Fresh and established primary USPC cell lines were found to express significantly more HER-2/neu receptor by flow cytometry (on the average, 10-fold greater) when compared with HER-2/neu-positive primary or established breast and ovarian cancer cell lines (P < 0.001). Importantly, although these USPC cell lines were resistant to chemotherapy in vivo and to natural killer- and complement-mediated cytotoxicity in vitro, they were found to be highly sensitive to Herceptin-mediated ADCC. USPC cell proliferation was also inhibited by Herceptin. A significant enhancement of ADCC was demonstrated when effector cells were exposed to low doses of IL-2 in vitro. Physiological concentrations of human serum IgG did not inhibit Herceptin-mediated ADCC against USPC., Conclusions: On the basis of these findings and previous reports showing a positive in vivo correlation between efficacy of Herceptin therapy and the level of HER-2/neu overexpression by tumor cells, we propose that Herceptin might be a novel and attractive therapeutic strategy in patients harboring chemotherapy-resistant, recurrent, or metastatic USPC.