Prospects for non-immunological molecular therapeutics in melanoma

In 2006 there were 60,000 new cases of cutaneous melanoma in the European Union and 13,000 deaths (www.europeancancerleagues.org). Currently available systemic treatment options for metastatic melanoma, including both cytotoxic and immunologic therapies, produce low rates of response and have modest survival impact. Therefore, there is an urgent need for effective novel therapies. Molecularly targeted treatments have demonstrated efficacy in certain cancers e.g. in HER2-positive breast cancer and in chronic myeloid leukaemia. Several pathways are currently being investigated as potential molecular targets in melanoma. The best studied is BRAF which is frequently mutated in melanoma. A multi tyrosine kinase inhibitor, sorafenib, which targets BRAF, has shown promising activity in preclinical studies and is currently being tested in combination with chemotherapy in patients with metastatic disease. In addition to BRAF, therapies which target other components of the Raf/Ras/MAPK pathway are being investigated. Other novel targets currently being investigated include the PI3/AKT pathway, tyrosine kinases, angiogenesis, poly (ADP ribose) polymerases, survivin and heat shock protein 90. Progress on preclinical and clinical evaluation of these novel targets in melanoma will be reviewed

CD10 − /ALDH − Cells are the Sole Cisplatin-Resistant Component of a Novel Ovarian Cancer Stem Cell Hierarchy

AbstractIt is long established that tumour-initiating cancer stem cells (CSCs) possess chemoresistant properties. However, little is known of the mechanisms involved, particularly with respect to the organisation of CSCs as stem-progenitor-differentiated cell hierarchies. Here we aimed to elucidate the relationship between CSC hierarchies and chemoresistance in an ovarian cancer model. Using a single cell-based approach to CSC discovery and validation, we report a novel, four-component CSC hierarchy based around the markers cluster of differentiation 10 (CD10) and aldehyde dehydrogenase (ALDH). In a change to our understanding of CSC biology, resistance to chemotherapy drug cisplatin was found to be the sole property of CD10−/ALDH− CSCs, while all four CSC types were sensitive to chemotherapy drug paclitaxel. Cisplatin treatment quickly altered the hierarchy, resulting in a three-component hierarchy dominated by the cisplatin-resistant CD10−/ALDH− CSC. This organisation was found to be hard-wired in a long-term cisplatin-adapted model, where again CD10−/ALDH− CSCs were the sole cisplatin-resistant component, and all CSC types remained paclitaxel-sensitive. Molecular analysis indicated that cisplatin resistance is associated with inherent- and adaptive-specific drug efflux and DNA-damage repair mechanisms. Clinically, low CD10 expression was consistent with a specific set of ovarian cancer patient samples. Collectively, these data advance our understanding of the relationship between CSC hierarchies and chemoresistance, which was shown to be CSC- and drug-type specific, and facilitated by specific and synergistic inherent and adaptive mechanisms. Furthermore, our data indicate that primary stage targeting of CD10−/ALDH− CSCs in specific ovarian cancer patients in future may facilitate targeting of recurrent disease, before it ever develops.</jats:p

New era for emerging therapeutic targeting human epidermal growth factor receptor 3 (HER 3) in advanced nonsmall cell lung cancer and metastatic breast cancer

Abstract Human epidermal growth factor receptor 3 (HER3) is a member of the transmembrane receptor tyrosine kinase family. Upregulation of HER3 pathway has been implicated as a mechanism of resistance in solid tumors, particularly in estrogen receptor positive, HER2 positive breast cancer and epidermal growth factor (EGFR) mutant nonsmall cell lung cancer. Several studies suggest that HER3 overexpression represents a negative prognostic biomarker associated with poor survival. Preclinical and clinical studies of anti‐HER3 investigational therapies suggest that expression of the HER3 ligand, neuregulin, may predict response to treatment. Despite its emergence as a key cancer therapeutic target, HER3 cannot be targeted with traditional tyrosine kinase inhibitors therapy due to its weak kinase activity. Monoclonal and bispecific antibodies targeting HER3 have been developed and tested in early phase trials. Objective responses were limited when first‐generation HER3‐specific monoclonal antibodies were investigated as monotherapies in phase 1 and 2 clinical trials for nonsmall cell lung cancer (NSCLC) and metastatic breast cancer (MBC). MBC and NSCLC HER3 specific antibody‐drug conjugates have shown encouraging results in resistance in cancer cells, particularly in those that overexpress HER3. These agents have shown some promise in early phase trials in both NSCLC and MBC setting in heavily pretreated patients with varying degrees of response. It is unclear which subgroup of patients will truly benefit from targeting HER3 as these therapies are under investigation

Evaluation of IGF1R and phosphorylated IGF1R as targets in HER2-positive breast cancer cell lines and tumours

Insulin-like growth factor-1 receptor (IGF1R) signalling is implicated in resistance to trastuzumab. However, the benefit of co-targeting HER2 and IGF1R has not been extensively studied, and the relationship between activated IGF1R and clinical response to trastuzumab has not been reported. This study aimed to evaluate the combination of trastuzumab with IGF1R tyrosine kinase inhibitors (TKIs) in a panel of HER2-positive breast cancer cell lines, and to examine the relationship between IGF1R expression and activation and response to trastuzumab in HER2-positve breast cancer patients. The anti-proliferative effects of trastuzumab combined with IGF1R TKIs BMS-536924 or NVP-AEW541 were measured in nine HER2-positive cell lines. IGF1R and phosphorylated IGF1R/insulin receptor (pIGF1R/IR) were measured by immunohistochemistry in 160 tumour samples from trastuzumab-treated patients (ICORG 06-22), and were related to clinicopathological parameters and survival. The HER2-positve cell lines displayed relatively low sensitivity to IGF1R TKIs alone (IC50s: 0.7 to >10 μM). However, when combined with trastuzumab, a significantly enhanced effect was observed in six of nine cells lines treated with BMS-36924 or NVP-AEW541. Yet, neither IGF1R nor pIGF1R were predictive of response to BMS-536924 or NVP-AEW541 alone, or in combination with trastuzumab. Cytoplasmic IGF1R staining was observed in all tumours, membrane IGF1R was detected in 13.8 % (22/160), and pIGF1R/IR was detected in 48.8 % (78/160). Although membrane IGF1R staining was associated with larger tumour size (p = 0.041), younger age at diagnosis (p = 0.048), and lower tumour grade (p = 0.024), no association between IGF1R or pIGF1R/IR and patient survival was observed. In conclusion, while neither IGF1R expression nor activation was predictive of response to trastuzumab, these pre-clinical data provide evidence that co-targeting HER2 and IGF1R may be beneficial in some HER2-amplified breast cancers; the identification of accurate biomarkers of IGF1R signalling will help to select patients most likely to benefit

Effects of HER family-targeting tyrosine kinase inhibitors on antibody-dependent cell-mediated cytotoxicity in HER2-expressing breast cancer

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 (HER2þ) 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 HER2þ (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 ¼ 0.03) and associated with trastuzumab response (P ¼ 0.01). TKI treatment altered mAb-induced NK cell-mediated ADCC in vitro, but it did not consistently correlate with HER2 expression in HER2þ 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.</p