HER2 aberrations in cancer: implications for therapy

Establishment of a patient-derived orthotopic Xenograft (PDOX) model of HER-2-positive cervical cancer expressing the clinical metastatic pattern

Squamous cell carcinoma of the cervix, highly prevalent in the developing world, is often metastatic and treatment resistant with no standard treatment protocol. Our laboratory pioneered the patient-derived orthotopic xenograft (PDOX) nude mouse model with the technique of surgical orthotopic implantation (SOI). Unlike subcutaneous transplant patient-derived xenograft (PDX) models, PDOX models metastasize. Most importantly, the metastasis pattern correlates to the patient. In the present report, we describe the development of a PDOX model of HER-2-positive cervical cancer. Metastasis after SOI in nude mice included peritoneal dissemination, liver metastasis, lung metastasis as well as lymph node metastasis reflecting the metastatic pattern in the donor patient. Metastasis was detected in 4 of 6 nude mice with primary tumors. Primary tumors and metastases in the nude mice had histological structures similar to the original tumor and were stained by an anti-HER-2 antibody in the same pattern as the patient's cancer. The metastatic pattern, histology and HER-2 tumor expression of the patient were thus preserved in the PDOX model. In contrast, subcutaneous transplantation of the patient's cervical tumors resulted in primary growth but not metastasis.

Upregulation of PD-L1 and APE1 is associated with tumorigenesis and poor prognosis of gastric cancer

INTRODUCTION

Gastric cancer is a fatal malignancy with a rising incidence rate. Effective methods for early diagnosis, monitoring metastasis, and prognosis are currently unavailable for gastric cancer. In this study, we examined the association of programmed death ligand-1 (PD-L1) and apurinic/apyrimidinic endonuclease 1 (APE1) expression with the prognosis of gastric cancer.

METHODS

The expressions of PD-L1 and APE1 were detected by immunohistochemistry in 107 cases of human gastric carcinoma. The correlation of PD-L1 and APE1 expression with the clinicopathologic features of gastric carcinoma was analyzed by SPSS version 19.0.

RESULTS

The positive expression rates of PD-L1 and APE1 in gastric cancer tissues were 50.5% (54/107) and 86.9% (93/107), respectively. PD-L1 and APE1 positive expressions were significantly associated with depth of invasion, lymph node metastasis, pathological type, overall survival, and higher T stage. Furthermore, the expression of PD-L1 in highly differentiated gastric cancers was higher than that in poorly differentiated cancers (P=0.008). Moreover, the expression of APE1 and PD-L1 in gastric cancers was positively correlated (r=0.336, P<0.01). Multivariate analysis showed that the depth of invasion was a significant prognostic factor (risk ratio 19.91; P=0.000), but there was no significant relationship with PD-L1, APE1, prognosis, and other characteristics.

CONCLUSION

The deregulation of PD-L1 and APE1 might contribute to the development and the poor prognosis of gastric cancer. Our findings suggest that high expression of PD-L1 and APE1 is a risk factor of gastric cancer and a new biomarker to predict the prognosis of gastric cancer. Furthermore, our findings suggest that targeting the PD-L1 and APE1 signaling pathways may be a new strategy for cancer immune therapy and targeted therapy for gastric cancer, especially in patients with deep invasion and lymph node metastasis.

Human Epidermal Growth Factor Receptor 2 (HER2/neu) in Salivary Gland Carcinomas: A Review of Literature

The aim of our study is to assess the relation of human epidermal growth factor receptor 2 or HER2/neu with the development of salivary gland carcinomas and use of Herceptin in the treatment of these cancers. A literature search was conducted using MEDLINE accessed via the National Library of Medicine PubMed interface searching for articles from 1994 up to 2014 relating to the existence of HER-2 protein and gene in salivary gland carcinomas and HER2/neu targeted therapy, written in English language. Almost all the studies in literature reported a frequent over expression and amplification of HER2/nue in salivary duct carcinomas (SDC) compared to other salivary gland cancers. Herceptin given as a monotherapy was not effective. The data on Herceptin combined chemotherapy are potentially promising but inadequate to evaluate drug activity, as patients also received a variety of cytotoxic agents. Therefore, Herceptin contribution to tumour response outcomes could not be precisely determined and the total number of cases is not sufficient. It is recommended that further work involves a large series of HER2/neu positive salivary gland cancers (randomized control trial) treated with chemotherapy with and without Herceptin. This might need multi-institutional cooperation.

Monitoring Trastuzumab Resistance and Cardiotoxicity: A Tale of Personalized Medicine

While approval of trastuzumab, a recombinant monoclonal antibody directed against HER2, along with a diagnostic kit to detect breast cancers which are positive for HER2 overexpression, has advanced a new era of stratified and personalized medicine, it also created several challenges to our scientific and clinical practice. These problems include trastuzumab resistance and trastuzumab-induced cardiotoxicity. In this review, we will summarize data from the literature regarding mechanisms of trastuzumab resistance and trastuzumab-induced cardiotoxicity and present some promising model systems that may advance our understanding of these mechanisms. Our discussion will include development of circulating tumor cells and circulating tumor DNA for monitoring tumor burden, of patient-derived xenograft models for preclinical testing of novel therapies, and of novel therapeutic strategies for trastuzumab-resistance and possible integration of these strategies in the design of co-clinical studies for testing in relevant patient subpopulations.

Evolution of targeted therapies in cancer: opportunities and challenges in the clinic

ABSTRACT 

Targeted therapies have changed the course of cancer treatment in recent years. By reducing toxicity and improving outcome, these new generations of precision medicines have extended patient lives beyond what could be achieved by the use of nontargeted therapies. In the last 2 years, several new molecular entities targeting signaling proteins and immune pathways have gone through successful clinical development resulting in their approval. These new targeted therapies require patient selection and the discovery of biomarkers of response. This review discusses the evolution of targeted therapies in cancer and challenges in translating the concepts into clinical practice.

T-DM1, a novel antibody-drug conjugate, is highly effective against uterine and ovarian carcinosarcomas overexpressing HER2

Ovarian and uterine carcinosarcoma (CS) are characterized by their aggressive clinical behavior and poor prognosis. We evaluated the efficacy of trastuzumab-emtansine (T-DM1), against primary HER2 positive and HER2 negative CS cell lines in vitro and in vivo. Eight primary CS cell lines were evaluated for HER2 amplification and protein expression by fluorescence in situ hybridization, immunohistochemistry, flow cytometry and qRT-PCR. Sensitivity to T-DM1-induced antibody-dependent-cell-mediated-cytotoxicity (ADCC) was evaluated in 4-h-chromium-release-assays. T-DM1 cytostatic and apoptotic activities were evaluated using flow cytometry based proliferation assays. In vivo activity of T-DM1 was also evaluated. HER2 protein overexpression and gene amplification were detected in 25 % (2/8) of the primary CS cell lines. T-DM1 and T were similarly effective in inducing strong ADCC against CS overexpressing HER2 at 3+ levels. In contrast, T-DM1 was dramatically more effective than T in inhibiting cell proliferation (P < 0.0001) and in inducing G2/M phase cell cycle arrest in the HER2 expressing cell lines (shift of G2/M: mean ± SEM from 14.87 ± 1.23 to 66.57 ± 4.56 %, P < 0.0001). Importantly, T-DM1 was highly active at reducing tumor formation in vivo in CS xenografts overexpressing HER2 (P = 0.0001 and P < 0.0001 compared to T and vehicle respectively) with a significantly longer survival when compared to T and vehicle mice (P = 0.008 and P = 0.0001 respectively). T-DM1 may represent a novel treatment option for the subset of HER2 positive CS patients with disease refractory to chemotherapy.

Multicentre randomised phase II trial of gemcitabine+platinum, with or without trastuzumab, in advanced or metastatic urothelial carcinoma overexpressing Her2

AIM

To investigate the efficacy and safety of gemcitabine and platinum salt, with or without trastuzumab, in patients with locally advanced or metastatic urothelial carcinoma overexpressing Her2.

METHODS

The main eligibility criterion was Her2 overexpression on immunohistochemistry (IHC 2+ or 3+) of primary tumour tissue confirmed by fluorescence in situ hybridisation (FISH). Patients were randomised to Arm A: gemcitabine 1000mg/m(2) (days 1 and 8) plus either cisplatin (70mg/m(2)) or carboplatin (AUC=5) (day 1 every 3 weeks) or Arm B: added trastuzumab (8mg/kg loading dose, then 6 mg/kg every 21 days until progression). The primary end-point was progression-free survival (PFS).

RESULTS

Among 563 screened patients, 75 (13.3%) were Her2 positive (IHC 2+/3+ and FISH+) and 61 met all eligibility criteria (median age, 64 years; 54/61 males; 50/61 baseline ECOG-PS 0-1; 11 locally advanced and 50 metastatic). There was no significant difference between Arms A and B in median PFS (10.2 versus 8.2 months, respectively, p=0.689), objective response rate (65.5% versus 53.2%, p=0.39), and median overall survival (15.7 versus 14.1 months, respectively, p=0.684). In an exploratory analysis, trastuzumab-treated patients receiving cisplatin rather than carboplatin-based chemotherapy fared better (PFS: 10.6 versus 8.0; OS: 33.1 versus 9.5 months). Myelosuppression was the main grade 3/4 toxicity. A case of grade 3 cardiotoxicity and one death from febrile neutropenia occurred in arm B.

CONCLUSION

The unexpectedly low incidence of Her2 overexpression precluded the detection of a significant difference in efficacy on addition of trastuzumab to platinum-based chemotherapy with gemcitabine. However, the satisfactory tolerance of the combination warrants further studies, especially of the cisplatin-based combination, in well-defined patient subsets.

Knockdown of EGFR inhibits growth and invasion of gastric cancer cells

The epidermal growth factor receptor (EGFR) is an oncogenic trans-membranous receptor, which is overexpressed in multiple human cancers. However, the role of EGFR in gastric cancer (GC) is still elusive. In this study, we aimed to investigate the expression and molecular mechanisms of EGFR in GC cells. Forty cases of GC and the corresponding adjacent non-cancerous tissues (ANCT) were collected, and the expression of EGFR was assessed using immunohistochemistry in biopsy samples. Furthermore, EGFR signaling was blocked by constructed recombinant small hairpin RNA lentiviral vector (Lv-shRAGE) used to transfect into human GC SGC-7901 cells. The expression of AKT, proliferating cell nuclear antigen (PCNA) and matrix metallopeptidase-9 (MMP-9) was detected by real-time PCR and western blotting assays. Cell proliferative activities and invasive capability were, respectively, determined by MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) and Transwell assays. Cell apoptosis and cycle distribution were analyzed by flow cytometry. EGFR was found highly expressed in cancer tissues compared with the ANCT and correlated with lymph node metastases. Knockdown of EGFR reduced cell proliferation and invasion of GC with decreased expression of AKT, PCNA and MMP-9 and induced cell apoptosis and cycle arrest. Upregulation of EGFR expression is associated with lymph node metastases of GC, and blockade of EGFR signaling suppresses growth and invasion of GC cells through AKT pathway, suggesting that EGFR may represent a potential therapeutic target for this aggressive malignancy.

Stromal expression of miR-21 identifies high-risk group in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype defined by the lack of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 expression. Expression of miR-21, an oncomiR, is frequently altered and may be distinctly expressed in the tumor stroma. Because tumor lesions are a complex mixture of cell types, we hypothesized that analysis of miR-21 expression at single-cell resolution could provide more accurate information to assess disease recurrence risk and BC-related death. We implemented a fully automated, tissue slide-based assay to detect miR-21 expression in 988 patients with BC. The miR-21(High) group exhibited shorter recurrence-free survival [hazard ratio (HR), 1.71; P < 0.001] and BC-specific survival (HR, 1.96; P < 0.001) in multivariate regression analyses. When tumor compartment and levels of miR-21 expression were considered, significant associations with poor clinical outcome were detected exclusively in tumor epithelia from estrogen receptor- and/or progesterone receptor-positive human epidermal growth factor receptor 2-negative cases [recurrence-free survival: HR, 3.67 (P = 0.006); BC-specific survival: HR, 5.13 (P = 0.002)] and in tumor stroma from TNBC cases [recurrence-free survival: HR, 2.59 (P = 0.013); BC-specific survival: HR, 3.37 (P = 0.003)]. These findings suggest that the context of altered miR-21 expression provides clinically relevant information. Importantly, miR-21 expression was predominantly up-regulated and potentially prognostic in the tumor stroma of TNBC.

A phase I trial of combination trastuzumab, lapatinib, and bevacizumab in patients with advanced cancer

PURPOSE

Preclinical data indicate that combination HER2-directed and anti-VEGF therapy may bypass resistance to trastuzumab. A phase I trial was performed to assess safety, activity, and correlates.

EXPERIMENTAL DESIGN

Patients with advanced, refractory malignancy were enrolled (modified 3 + 3 design with expansions for responding tumor types). Patients received lapatinib daily for 21 days, and bevacizumab and trastuzumab every 3 weeks. Correlates included HER2 extracellular domain levels (ECD) and single nucleotide polymorphisms (SNPs).

RESULTS

Ninety-four patients were treated (median = four prior systemic therapies). The most common related adverse events ≥ grade 2 were diarrhea (n = 33, 35 %) and hypertension (n = 10, 11 %). The recommended phase 2 dose was trastuzumab 6 mg/m(2) (loading = 8 mg/m(2)) and bevacizumab 15 mg/kg every 3 weeks, with lapatinib 1,250 mg daily (full FDA-approved dose of each drug). One patient (1 %) achieved a complete response (CR); eight (9 %), a partial response (PR) (includes breast (n = 7, one of which was HER2 2+ by IHC) and salivary ductal carcinoma (n = 1); and 14 (15 %), stable disease (SD) ≥6 months (total SD ≥ 6 months/PR/CR =23 (25 %). All patients with PR/CR received prior trastuzumab +/- lapatinib. SD ≥ 6 months/PR/CR rate and time to treatment failure (TTF) correlated with elevated baseline HER2 ECD (N = 75 patients tested) but not with HER2 SNPs.

CONCLUSIONS

Combination trastuzumab, lapatinib, and bevacizumab was well-tolerated and demonstrated antitumor activity in heavily pretreated patients with advanced malignancy.

Molecular mechanisms underlying the role of microRNAs in the chemoresistance of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is an extremely severe disease where the mortality and incidence rates are almost identical. This is mainly due to late diagnosis and limited response to current treatments. The tumor macroenvironment/microenvironment have been frequently reported as the major contributors to chemoresistance in PDAC, preventing the drugs from reaching their intended site of action (i.e., the malignant duct cells). However, the recent discovery of microRNAs (miRNAs) has provided new directions for research on mechanisms underlying response to chemotherapy. Due to their tissue-/disease-specific expression and high stability in tissues and biofluids, miRNAs represent new promising diagnostic and prognostic/predictive biomarkers and therapeutic targets. Furthermore, several studies have documented that selected miRNAs, such as miR-21 and miR-34a, may influence response to chemotherapy in several tumor types, including PDAC. In this review, we summarize the current knowledge on the role of miRNAs in PDAC and recent advances in understanding their role in chemoresistance through multiple molecular mechanisms.

Trastuzumab emtansine is active on HER-2 overexpressing NSCLC cell lines and overcomes gefitinib resistance

Background

HER-2 represents a relatively new therapeutic target for non small cell lung cancer (NSCLC) patients. The incidence for reported HER-2 overexpression/amplification/mutations ranges from 2 to 20% in NSCLC. Moreover, HER-2 amplification is a potential mechanism of resistance to tyrosine kinase inhibitors of the epidermal growth factor receptor (EGFR-TKI) (about 10% of cases). T-DM1, trastuzumab emtansine is an antibody-drug conjugate composed by the monoclonal antibody trastuzumab and the microtubule polymerization inhibitor DM1. The activity of T-DM1 has been studied in breast cancer but the role of T-DM1 in lung cancer remains unexplored.

Methods

Antiproliferative and proapoptotic effects of T-DM1 have been investigated in different NSCLC cell lines by MTT, crystal violet staining, morphological study and Western blotting. HER-2 expression and cell cycle were evaluated by flow cytometry and Western blotting. Antibody dependent cell cytotoxicity (ADCC) was measured with a CytoTox assay. Xenografted mice model has been generated using a NSCLC cell line to evaluate the effect of T-DM1 on tumor growth. Moreover, a morphometric and immunohistochemical analysis of tumor xenografts was conducted.

Results

In this study we investigated the effect of T-DM1 in a panel of NSCLC cell lines with different HER-2 expression levels, in H1781 cell line carrying HER-2 mutation and in gefitinib resistant HER-2 overexpressing PC9/HER2cl1 cell clone. T-DM1 efficiently inhibited proliferation with arrest in G2-M phase and induced cell death by apoptosis in cells with a significant level of surface expression of HER-2. Antibody-dependent cytotoxicity assay documented that T-DM1 maintained the same activity of trastuzumab. Our data also suggest that targeting HER-2 with T-DM1 potentially overcomes gefitinib resistance. In addition a correlation between cell density/tumor size with both HER-2 expression and T-DM1 activity was established in vitro and in an in vivo xenograft model.

Conclusions

Our results indicate that targeting HER-2 with T-DM1 may offer a new therapeutic approach in HER-2 over-expressing lung cancers including those resistant to EGFR TKIs.