Raya Leibowitz-Amit

Mimp, a Mitochondrial Carrier Homologue, Inhibits Met-HGF/SF-Induced Scattering and Tumorigenicity by Altering Met-HGF/SF Signaling Pathways

We have recently shown that Mimp, a mitochondrial carrier protein homologue, is induced by Met-hepatocyte growth factor/scatter factor (HGF/SF) signaling and decreases the mitochondrial membrane potential in DA3 mammary adenocarcinoma cells. We show here that induction of Mimp leads to growth arrest in response to HGF/SF by arresting cells at the S phase of the cell cycle. Induction of Mimp or its transient expression does not lead to apoptosis. Mimp also attenuates HGF/SF-induced cellular scattering in vitro and tumor growth in vivo. The exogenous induction of Mimp at levels similar to its endogenous induction by HGF/SF increases the level of the Met protein and its phosphorylation by HGF/SF but reduces the levels of Shc and prevents the HGF/SF-induced tyrosine phosphorylation of Grb2 and Shc. In contrast, the level of phosphatidylinositol 3-kinase (PI3K) increases following Mimp induction and the level of phosphorylated PI3K in response to HGF/SF is unaffected by the exogenous induction of Mimp. Moreover, exogenous Mimp prevents the HGF/SF-induced transcription of the serum response element-luciferase reporter gene. Our results show that Mimp expression reduces Met-HGF/SF-induced proliferation and scattering by attenuating and altering the downstream signaling of Met. These data show a new link between a tyrosine kinase growth factor receptor and a mitochondrial carrier homologue that regulates cellular growth, motility, and tumorigenicity.

Is there a "Trial Effect" on Outcome of Patients with Metastatic Renal Cell Carcinoma Treated with Sunitinib?

Purpose Studies suggested the existence of a ‘trial effect, in which for a given treatment, participation in a clinical trial is associated with a better outcome. Sunitinib is a standard treatment for metastatic renal cell carcinoma (mRCC). We aimed to study the effect of clinical trial participation on the outcome of mRCC patients treated with sunitinib, which at present, is poorly defined. Materials and Methods The records of mRCC patients treated with sunitinib between 2004-2013 in 7 centers across 2 countries were reviewed. We compared the response rate (RR), progression free survival (PFS), and overall survival (OS), between clinical trial participants (n=49) and a matched cohort of non-participants (n=49) who received standard therapy. Each clinical trial participant was individually matched with a non-participant by clinicopathologic factors. PFS and OS were determined by Cox regression. Results The groups were matched by age (median 64), gender (male 67%), Heng risk (favorable 25%, intermediate 59%, poor 16%), prior nephrectomy (92%), RCC histology (clear cell 86%), pre-treatment NLR (>3 in 55%, n=27), sunitinib induced hypertension (45%), and sunitinib dose reduction/treatment interruption (41%). In clinical trial participants versus non-participants, RR was partial response/stable disease 80% (n=39) versus 74% (n=36), and progressive disease 20% (n=10) versus 26% (n=13) (p=0.63, OR 1.2). The median PFS was 10 versus 11 months (HR=0.96, p=0.84), and the median OS 23 versus 24 months (HR=0.97, p=0.89). Conclusions In mRCC patients treated with sunitinib, the outcome of clinical trial participants was similar to that of non-participants who received standard therapy.

Alterations of microRNAs throughout the malignant evolution of cutaneous squamous cell carcinoma: The role of miR-497 in epithelial to mesenchymal transition of keratinocytes

Skin carcinogenesis is known to be a multi-step process with several stages along its malignant evolution. We hypothesized that transformation of normal epidermis to cutaneous squamous cell carcinoma (cSCC) is causally linked to alterations in microRNAs (miRNA) expression. For this end we decided to evaluate their alterations in the pathologic states ending in cSCC. Total RNA was extracted from formalin fixed paraffin embedded biopsies of five stages along the malignant evolution of keratinocytes towards cSCC: Normal epidermis, solar elastosis, actinic keratosis KIN1-2, advanced actinic keratosis KIN3 and well-differentiated cSCC. Next-generation small RNA sequencing was performed. We found that 18 miRNAs are overexpressed and 28 miRNAs are underexpressed in cSCC compared to normal epidermis. miR-424, miR-320, miR-222 and miR-15a showed the highest fold change among the overexpressed miRNAs. And miR-100, miR-101 and miR-497 showed the highest fold change among the underexpressed miRNAs. Heat map of hierarchical clustering analysis of significantly changed miRNAs and principle component analysis disclosed that the most prominent change in miRNAs expression occurred in the switch from ‘early’ stages; normal epidermis, solar elastosis and early actinic keratosis to the ‘late’ stages of epidermal carcinogenesis; late actinic keratosis and cSCC. We found several miRNAs with ‘stage specific’ alterations while others display a clear ‘gradual’, either progressive increase or decrease in expression along the malignant evolution of keratinocytes. The observed alterations focused in miRNAs involved in the regulation of AKT/mTOR or in those involved in epithelial to mesenchymal transition. We chose to concentrate on the evaluation of the molecular role of miR-497. We found that it induces reversion of epithelial to mesenchymal transition. We proved that SERPINE-1 is its biochemical target. The present study allows us to further study the pathways that are regulated by miRNAs along the malignant evolution of keratinocytes towards cSCC.

High-Throughput Architecture for Discovering Combination Cancer Therapeutics

Purpose The amount of available next-generation sequencing data of tumors, in combination with relevant molecular and clinical data, has significantly increased in the last decade and transformed translational cancer research. Even with the progress made through data-sharing initiatives, there is a clear unmet need for easily accessible analyses tools. These include capabilities to efficiently process large sequencing database projects to present them in a straightforward and accurate way. Another urgent challenge in cancer research is to identify more effective combination therapies. Methods We have created a software architecture that allows the user to integrate and analyze large-scale sequencing, clinical, and other datasets for efficient prediction of potential combination drug targets. This architecture permits predictions for all genes pairs; however, Food and Drug Administration-approved agents are currently lacking for most of the identified gene targets. Results By applying this approach, we performed a comprehensive study and analyzed all possible combination partners and identified potentially synergistic target pairs for 38 approved targets currently in clinical use. We further showed which genes could be synergistic prediction markers and potential targets with MAPK/ERK inhibitors for the treatment of melanoma. Moreover, we integrated a graph analytics technique in this architecture to identify pathways that could be targeted synergistically to enhance the efficacy of certain therapeutics in cancer. Conclusion The architecture and the results presented provide a foundation for discovering effective combination therapeutics.

Association between the Absolute Baseline Lymphocyte Count and Response to Neoadjuvant Platinum-based Chemotherapy in Muscle-invasive Bladder Cancer

AIMSnPlatinum-based neoadjuvant chemotherapy (NAC) improves overall survival in muscle-invasive bladder cancer (MIBC). A pathological complete response (pCR) at radical cystectomy after NAC is associated with better overall survival, but there are no established predictive biomarkers of response to NAC in MIBC. The aim of this study was to find laboratory variables associated with pCR following NAC.nnnMATERIALS AND METHODSnWe carried out a retrospective review of MIBC patients treated with NAC followed by radical cystectomy at the Sheba Medical Center between 2005 and 2015. Overall survival was calculated using the Kaplan-Meier product-limit method and compared between patients who achieved or did not achieve pCR using the Log-rank test. Baseline and pre-surgery laboratory values were collected and compared between patients who subsequently achieved pCR and those who did not using logistic regression.nnnRESULTSnFifty-eight patients underwent radical cystectomy after NAC, with a median follow-up of 32 (range 4.8-111.4) months from diagnosis. Of 55 patients with documented pathological outcome on radical cystectomy, 17 (31%) achieved pCR (complete responders). Of the 15 complete responders with follow-up data, 13 (87%) were still alive at time of last follow-up for this study (July 2015). Patients who did not achieve pCR had a significantly worse overall survival than complete responders (Pxa0=xa00.0007). The baseline lymphocyte count, neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR) were significantly associated with response (Pxa0=xa00.037, Pxa0=xa00.045, Pxa0=xa00.042, respectively) on univariate analysis, whereas baseline albumin, haemoglobin, neutrophils, platelets and the total white blood count were not significantly associated with response. Lymphocyte counts were significantly higher in responders than non-responders throughout three time points (Pxa0=xa00.003 using a generalised linear mixed model).nnnCONCLUSIONSnA high baseline level of lymphocytes is associated with the achievement of pCR at radical cystectomy after NAC, which, in turn, is associated with a significantly longer overall survival. Our results suggest that chemosensitivity in MIBC is associated with lymphocyte count.

Abstract 5602: Regulation of immune checkpoint genes revealed by a melanoma tumor cancer genome atlas (TCGA) analysis - potential implications for improving immunotherapy

Introduction: The interface between T lymphocytes and cancer or antigen presenting cells (C/APCs) is multi-faceted and complex. This interface, now designated 9the immunological synapse9, comprises of both co-inhibitory and co-stimulatory transmembrane protein pairs (9checkpoint proteins9) that all serve to modulate the signal transmitted to the T lymphocyte, leading to either activation, anergy or exhaustion. Immune checkpoint inhibitors have anti-neoplastic activity in a wide range of malignancies, but not all cancers and not all patients with a given cancer respond to the currently available checkpoint inhibitors. Micro-RNAs (miRNAs) are short intracellular RNA molecules known to be master regulators of gene expression. Our aim was to study the associations between a miRNA that was previously implicated in cancer and immune checkpoint genes. Methods: Bioinformatic analyses of the expression of mRNAs and miRNAs from 451 samples was performed using the melanoma TCGA database. Correlation coefficients between the expression of mRNAs or mRNAs/miRNAs were calculated using the Spearman rho method. Survival analysis was performed using the Kaplan-Meier method. Potential 39UTR binding sites of miRNAs were found using the web-based tool www.targetscan.org. Results: Of 22 mRNAs of checkpoint genes assessed, the expression of 19 was highly positively correlated to each other. These mRNAs code for both co-inhibitory and co-stimulatory proteins at the T cell and the C/APC sides of the immunological synapse, suggesting that there is joint transcriptional regulation on the expression of these checkpoint genes. The expression of one specific miRNA was also significantly positively correlated with the expression of eight of these checkpoint mRNAs (PD1L, PD1L, B7.1, ICOS, BTLA, LAG3, CTLA4, TNFRSF9). The significant positive correlation between this miRNA and B7.1 and PD1L was verified in 18 cell lines in vitro, with rho correlation coefficients of 0.72 and 0.61, respectively (p=0.001 and 0.01, respectively). This possibly indicates a joint transcriptional regulation on this miRNA and the mRNAs. Bioinformatic analyses suggest that this miRNA may potentially target the 39UTR of 6 of these mRNAs (PD1, PD1L, B7.1, ICOS, BTLA, TNFRSF9). Data from 163 stage III melanoma patients with documented survival data show that a high expression level of this miRNA and a low expression level of either B7.1, B7.2, CD28, ICOS, ICOSL, OX40, OX40L, TNFRSF18 or PD1L was each significantly associated with poor prognosis relative to all other expression groups. Eight of these nine mRNAs are co-stimulatory. Conclusions: It is tempting to speculate that aberrant co-regulation of the miRNA-mRNAs, leading to high levels of the miRNA and low levels of co-stimulatory checkpoint genes is associated with worse outcome, potentially as a result of 9immune evasion9 due to decreased co-stimulation at the synapse. Citation Format: Raya Leibowitz-Amit, Jason Roszik, Dror Avni, Elizabeth Grimm. Regulation of immune checkpoint genes revealed by a melanoma tumor cancer genome atlas (TCGA) analysis - potential implications for improving immunotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5602. doi:10.1158/1538-7445.AM2017-5602

Baseline neutrophil to lymphocyte ratio as a prognostic marker for patients with muscle-invasive bladder cancer being treated with neoadjuvant chemotherapy.

468 Background: The neutrophil-to-lymphocyte ratio (NLR), an inflammatory marker, has been associated with a poor prognosis in several solid malignancies. In muscle-invasive bladder cancer (MIBC), an elevated pre-cystectomy NLR has been shown to predict for poor survival; however, its role in prognostication for patients being treated with neoadjuvant chemotherapy (NAC) is unknown. We evaluated the baseline NLR as an independent prognostic factor in patients with MIBC treated with NAC. Methods: Patients with MIBC treated with NAC in Alberta from 2005 to 2015, and at the Princess Margaret Hospital in Ontario from 2005 to 2013 were evaluated. All 290 patients treated with NAC were included; 272 were evaluable for NLR and outcomes. Patient, disease, and treatment-related factors were evaluated. NLR was examined prior to initiation of preoperative chemotherapy. The prognostic role of NLR on overall survival (OS) and progression-free survival (PFS) was determined using Cox proportional hazard regression analys...

Association of changes in biomarkers with treatment with cabozantinib (Cabo) in metastatic castration-resistant prostate cancer (mCRPC): A post-hoc analysis of the 100mg nonrandomized expansion cohort of a randomized discontinuation trial.

196 Background: Cabo, an oral inhibitor of receptor tyrosine kinases (RTK) including MET and VEGFR2, showed activity in early clinical studies in mCRPC, and is being investigated in phase 3 trials. Our primary aim was to retrospectively study the potential association between plasma concentrations of known markers of hypoxia, RTK cell signaling, inflammation, bone metabolism, chemo-attraction and epithelial-mesenchymal transition with response to Cabo in patients (pts) who received 100mg daily as part of a phase 2 non-randomized expansion cohort (NCT00940225). Methods: Our cohort of mCRPC pts with available plasma samples comprised of 81 pts with bone lesions assessed for bone scan response (BSR, defined as ≥30% decrease in lesion area compared to baseline). Thirty three pts also had measurable disease and were assessed for RECIST response. Plasma samples were available for all pts at baseline, at 6 weeks and at time of best response. Levels of 27 plasma biomarkers were measured in duplicate using ELISA. ...

Abstract 3721: Rapid widening of age and race health disparities in prostate cancer outcomes within the United States, 1973-2014:

Introduction Little is known concerning how cancer-outcome disparities have changed over time. We investigated how age and race disparities in prostate cancer (PCa) survival have changed in the USA over the last 40 years. Methods We utilized the SEER database to track PCa outcomes. Incl. criteria: subjects with PCa diagnosed 1973 - 2008, aged 50-89 yrs. Excl. criteria: multiple primary cancers, unknown stage. Results 658,916 PCa patients were analyzed. Median follow up for alive patients was 54m (interquart. range 39-75m). Median age of diagnosis decreased from 73 to 60 yrs from 1973 to 2008, and the proportion aged > = 70 yrs decreased from 62% to 40%. The proportion diagnosed with metastatic disease decreased from 18% to 4%; likewise amongst those with M0 disease the proportion with T3-4 decreased from 41% to 17%. The remainder of the results are confined to M0 disease. Four-year cancer specific death decreased progressively for all age groups. But whereas 4 year cancer specific mortality dropped from 24% to 3% in those aged 50-54, it only decreased from 38% to 18% in those aged 85-89. Whereas the hazard ratio (HR) for cancer-specific death for those aged 85-89 (50-54 year old subjects reference group) was 1.6 in 1973-9, in 2000-8 it was 10.9 (table). The widening age disparities were only marginally altered by incorporation of ‘tumor stage’ into the model. Similar widening age disparities were seen in metastatic disease. Race-related disparities also widened over the study period; the HR for death increasing from 1.1 (1973-79) to 1.3 (2000-8). Conclusions Age- and Race- related health disparities in survival outcomes in both metastatic and non-metastatic prostate cancer have greatly widened over the past 40 years; this effect appears to be accelerating and is not explained by delayed diagnosis. Since outcome disparities have grown against a backdrop of improved screening, diagnosis and treatment, it appears that measures targeted at these populations will be needed in order to redress the imbalance. Citation Format: Richard J. Lawrence, Damien Urban, Talia Golan, Akram Saad, Raanan Berger, Raya Leibowitz-Amit, Jair Bar, Robert Den, Jeffrey Goldstein, Zvi Symon. Rapid widening of age and race health disparities in prostate cancer outcomes within the United States, 1973-2014. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3721. doi:10.1158/1538-7445.AM2015-3721

Neoadjuvant gemcitabine-cisplatin (GC) for muscle-invasive bladder cancer (MIBC): Does midway CT staging predict for pathologic complete response (pCR)?

306 Background: Neoadjuvant cisplatin-based chemotherapy (NC) improves overall survival in MIBC, with pCR post radical cystectomy (RC) linked to better outcomes. NC is underutilized in part due to concerns over disease progression during NC. Midway radiological CT (post 2 NC cycles) may identify patients (pts) progressing on NC who should proceed to definitive therapy (DT). Methods: We reviewed 39 MIBC pts planned to receive 4 cycles of NC (GC) between Jan2005-April2013. Most pts (70%) had midway CT staging. A radiological response was defined as clear improvement in tumour +/- nodal status on CT compared to baseline, taking into account prior trans-urethral resection of bladder tumour; any other result was considered no response. DT consisted of RC, concurrent chemoradiation (CCR), or radiation alone (R). Descriptive statistics and Fisher’s exact test examined associations between disease characteristics and outcomes. Results: Overall, 28 pts (72%) completed planned NC; 7 pts (18%) stopped early due to n...