Neuropilin-2b facilitates resistance to tyrosine kinase inhibitors in non-small cell lung cancer.

OBJECTIVE: Innate and acquired resistance is the principle factor limiting the efficacy of tyrosine kinase inhibitors in lung cancer. We have observed a dramatic upregulation of the cell surface co-receptor neuropilin-2b in lung cancers clinically treated with tyrosine kinase inhibitors correlating with acquired resistance. We hypothesize that neuropilin-2b plays a functional role in acquired tyrosine kinase inhibitor resistance. METHODS: Non-small cell lung cancer proliferation and survival were determined during chronic tyrosine kinase inhibitor exposure in the presence or absence of neuropilin-2b knock-down. Interactions of neuropilin-2a and neuropilin-2b isoforms with PTEN and GSK3ß were assessed by immunoprecipitation. Neuropilin-2a and neuropilin-2b mutants deleted for their cytoplasmic domains were used to identify regions responsible for neuropilin-2b-GSK3ß interaction. Because GSK3ß is known to phosphorylate and degrade PTEN, phospho-PTEN and total PTEN levels were assessed after transfection of neuropilin-2a and neuropilin-2b wild-type and mutant constructs. RESULTS: Non-small cell lung cancer cells chronically treated with gefitinib or osimertinib developed drug resistance and exhibited logarithmic growth in the presence of endothelial growth factor receptor tyrosine kinase inhibitors. However, neuropilin-2b knockdown cells remained sensitive to gefitinib. Likewise, neuropilin-2b knockdown suppressed and neuropilin-2a knockdown enhanced cellular migration. Acquired drug resistance and cell migration correlated with neuropilin-2b-dependent AKT activation with the intermediate step of GSK3ß-dependent PTEN degradation. A specific binding site for GSK3ß on the cytoplasmic domain of neuropilin-2b was identified with truncated protein constructs and computer modeling. CONCLUSIONS: Neuropilin-2b facilitates non-small cell lung cancer resistance to tyrosine kinase inhibitors, and this biological effect relates to AKT activation. Neuropilin-2b GSK3ß interactions appear to be essential for PTEN degradation and AKT activation in lung cancer cells. Disruption of the neuropilin-2b GSK3ß interaction may represent a novel treatment strategy to preserve sensitivity to tyrosine kinase inhibitors in non-small cell lung cancer.

Cabozantinib, a New Standard of Care for Patients With Advanced Renal Cell Carcinoma and Bone Metastases? Subgroup Analysis of the METEOR Trial.

Purpose Cabozantinib, an inhibitor of tyrosine kinases including MET, vascular endothelial growth factor receptors, and AXL, increased progression-free survival (PFS), overall survival (OS), and objective response rate (ORR) in patients with advanced renal cell carcinoma (RCC) after previous vascular endothelial growth factor receptor-targeted therapy in the phase III METEOR trial. Because bone metastases are associated with increased morbidity in patients with RCC, bone-related outcomes were analyzed in METEOR. Patients and Methods Six hundred fifty-eight patients were randomly assigned 1:1 to receive 60 mg cabozantinib or 10 mg everolimus. Prespecified subgroup analyses of PFS, OS, and ORR were conducted in patients grouped by baseline bone metastases status per independent radiology committee (IRC). Additional end points included bone scan response per IRC, skeletal-related events, and changes in bone biomarkers. Results For patients with bone metastases at baseline (cabozantinib [n = 77]; everolimus [n = 65]), median PFS was 7.4 months for cabozantinib versus 2.7 months for everolimus (hazard ratio, 0.33 [95% CI, 0.21 to 0.51]). Median OS was also longer with cabozantinib (20.1 months v 12.1 months; hazard ratio, 0.54 [95% CI, 0.34 to 0.84]), and ORR per IRC was higher (17% v 0%). The rate of skeletal-related events was 23% with cabozantinib and 29% with everolimus, and bone scan response per IRC was 20% versus 10%, respectively. PFS, OS, and ORR were also improved with cabozantinib in patients without bone metastases. Changes in bone biomarkers were greater with cabozantinib than with everolimus. The overall safety profiles of cabozantinib and everolimus in patients with bone metastases were consistent with those observed in patients without bone metastases. Conclusion Cabozantinib treatment was associated with improved PFS, OS, and ORR when compared with everolimus treatment in patients with advanced RCC and bone metastases and represents a good treatment option for these patients.

A Phase II Multi-Center Study of Bevacizumab in Combination with Ixabepilone in Subjects with Advanced Renal Cell Carcinoma.

LESSONS LEARNED: Accrual to renal cell carcinoma trials remains a challenge despite the lack of prolonged response to the available treatments.The observation of three responses among the 30 patients with median progression-free survival and overall survival of 8.3 and 15 months, respectively, indicates the combination has some activity, but it is not sufficient for further development. BACKGROUND: Treatment of metastatic renal cell carcinoma (mRCC) remains suboptimal. Preclinical data have previously shown that ixabepilone, a microtubule-stabilizing agent approved for the treatment of breast cancer, is active in taxane-sensitive and -resistant cells. In this single-arm phase II trial, we investigated a combination of ixabepilone plus bevacizumab in patients with refractory mRCC. METHODS: We enrolled 30 patients with histologically confirmed mRCC, clear cell subtype, who had not been previously treated with ixabepilone or bevacizumab but had received at least one prior U.S. Food and Drug Administration (FDA)-approved treatment for renal cell carcinoma (RCC). The treatment regimen consisted of 6 mg/m2 ixabepilone per day for 5 days and 15 mg/kg bevacizumab every 21 days. After 6 cycles, the treatment interval could be extended to every 28 days. The primary endpoint was the objective response rate according to the Response Evaluation Criteria in Solid Tumors (RECIST). Secondary endpoints were progression-free survival (PFS), overall survival (OS), and the toxicity of the combination. RESULTS: The median number of prior therapies was two (range per patient one to five). Patients received a median of 8 cycles of ixabepilone plus bevacizumab (range 2-54). The median follow-up was 36.4 months (range 23.5-96.5). Nineteen patients (63.3%) had stable disease as a best response. Three patients (10%) had a partial response. The median PFS was 8.3 months (95% confidence interval [CI], 4.9-10.6) and the median OS was 15.0 months (95% CI, 11.3-28.8). The total number of cycle for safety evaluation was 289. Grade 3/4 adverse events (>5% incidence) included lymphopenia (16.7%), hypertension (6.7%), and leukopenia (6.7%). CONCLUSION: The combination of ixabepilone and bevacizumab was well tolerated, with modest activity in second - or later-line mRCC, but it is not recommended as a therapy without further clinical development. Alternative combinations with these agents could be explored in future studies.

Epigenetic Regulation of the Epithelial to Mesenchymal Transition in Lung Cancer.

Lung cancer is the leading cause of cancer deaths worldwide. It is an aggressive and devastating cancer because of metastasis triggered by enhanced migration and invasion, and resistance to cytotoxic chemotherapy. The epithelial to mesenchymal transition (EMT) is a fundamental developmental process that is reactivated in wound healing and a variety of diseases including cancer where it promotes migration/invasion and metastasis, resistance to treatment, and generation and maintenance of cancer stem cells. The induction of EMT is associated with reprogramming of the epigenome. This review focuses on major mechanisms of epigenetic regulation mainly in lung cancer with recent data on EZH2 (enhancer of zeste 2 polycomb repressive complex 2 subunit ), the catalytic subunit of the PRC2 (Polycomb Group PcG), that behaves as an oncogene in lung cancer associated with gene repression, non-coding RNAs and the epitranscriptome.

The neuropilin 2 isoform NRP2b uniquely supports TGFß-mediated progression in lung cancer.

Neuropilins (NRP1 and NRP2) are co-receptors for heparin-binding growth factors and class 3 semaphorins. Different isoforms of NRP1 and NRP2 are produced by alternative splicing. We found that in non-small cell lung cancer (NSCLC) cell lines, transforming growth factor-ß (TGFß) signaling preferentially increased the abundance of NRP2b. NRP2b and NRP2a differ only in their carboxyl-terminal regions. Although the presence of NRP2b inhibited cultured cell proliferation and primary tumor growth, NRP2b enhanced cellular migration, invasion into Matrigel, and tumorsphere formation in cultured cells in response to TGFß signaling and promoted metastasis in xenograft mouse models. These effects of overexpressed NRP2b contrast with the effects of overexpressed NRP2a. Hepatocyte growth factor (HGF)-induced phosphorylation of the kinase AKT was specifically promoted by NRP2b, whereas inhibiting the HGF receptor MET attenuated NRP2b-dependent cell migration. Unlike NRP2a, NRP2b did not bind the PDZ domain scaffolding protein GAIP carboxyl terminus-interacting protein (GIPC1) and only weakly recruited phosphatase and tensin homolog (PTEN), potentially explaining the difference between NRP2b-mediated and NRP2a-mediated effects. Analysis of NSCLC patient tumors showed that NRP2b abundance correlated with that of the immune cell checkpoint receptor ligand PD-L1 as well as with epithelial-to-mesenchymal transition (EMT) phenotypes in the tumors, acquired resistance to epidermal growth factor receptor (EGFR) inhibitors, disease progression, and poor survival in patients. NRP2b knockdown attenuated the acquisition of resistance to the EGFR inhibitor gefitinib in cultured NSCLC cells. Thus, in NSCLC, NRP2b contributed to the oncogenic response to TGFß and correlated with tumor progression in patients.

A phase 2 study of the sphingosine-1-phosphate antibody sonepcizumab in patients with metastatic renal cell carcinoma.

BACKGROUND: Upregulation of sphingosine-1-phosphate (S1P) may mediate resistance to vascular endothelial growth factor (VEGF)-directed therapies and inhibit antitumor immunity. Antagonism of S1P in preclinical models appears to overcome this resistance. In this phase 2 study, the authors assessed the activity of sonepcizumab, a first-in-class inhibitor of S1P, in patients with metastatic renal cell carcinoma (mRCC) with a history of prior VEGF-directed therapy. METHODS: Patients were required to have clear cell mRCC and to have received treatment with at least 1 prior VEGF-directed agent. Prior treatment with immunotherapeutic agents and ≤1 mammalian target of rapamycin inhibitors was permitted. The primary endpoint of the study was progression-free survival. Additional endpoints included response rate and safety, and overall survival (OS) performed post hoc. RESULTS: A total of 40 patients were enrolled with a median of 3 prior therapies (range, 1-5 prior therapies), 78% of whom had intermediate-risk disease by second-line International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) criteria. Although the current study did not achieve its primary endpoint based on the 2-month progression-free survival, a median OS of 21.7 months was observed. Four patients (10%) demonstrated a partial response, with a median duration of response of 5.9 months. No grade 3/4 treatment-related adverse events were observed in >5% of patients (adverse events were graded and recorded for each patient using Common Terminology Criteria for Adverse Events [version 4.0]); the most frequent grade 1/2 treatment-related adverse events were fatigue (30%), weight gain (18%), constipation (15%), and nausea (15%). Biomarker studies demonstrated an increase in S1P concentrations with therapy. Comprehensive genomic profiling of 3 patients with a clinical benefit of >24 months indicated von Hippel-Lindau (VHL) and polybromo-1 (PBRM1) alterations. CONCLUSIONS: The encouraging OS and favorable safety profile observed with sonepcizumab should prompt further investigation of the agent in combination with VEGF-directed agents or checkpoint inhibitors. Cancer 2017;123:576-582. © 2016 American Cancer Society.

Erratum: Roche, J. et al. Global Decrease of Histone H3K27 Acetylation in ZEB1-Induced Epithelial to Mesenchymal Transition in Lung Cancer Cells. Cancers, 2013, 5, 334-356.

n/a.

Urothelial carcinoma of donor origin in a kidney transplant patient.

BACKGROUND: Malignancy after transplantation is an uncommon multifactorial occurrence. Immunosuppression to prevent graft rejection is described as a major risk factor in malignancy development in the post-transplant state. Donor-derived malignancy is a rare reported complication. Herein, we review our patient history and discuss diagnostic strategies and the implications of immunosuppression for donor-derived malignancy. CASE PRESENTATION: This is a 69-year-old man with post-renal-transplant urothelial carcinoma determined to be of donor origin. His course was complicated by BK virus at six years post-transplant; urothelial carcinoma was identified nine years post-transplant. Cystectomy was performed, but because of immunosuppression and underlying chronic kidney disease, the patient was considered ineligible for adjuvant chemotherapy. Two years after resection, screening MRI demonstrated retroperitoneal lymphadenopathy and a right upper pole mass in the transplanted kidney. Urine cytology confirmed the presence of malignant cells; FISH showed 2-8 copies of the X chromosome and no Y chromosome consistent with female origin of the malignant cells. CT-guided renal mass and paraaortic lymph node biopsies demonstrated that about 50 % of cells had an XY complement, while the remainder showed a XX genotype by chromosomal SNP microarray analysis. Immunosuppression was discontinued and the donor kidney removed. X/Y FISH of the urothelial carcinoma identified in the explanted kidney confirmed that the malignant cells were of female donor origin. Follow-up at 3, 6 and 12 months after discontinuation of immunosuppression and surgery demonstrated normalization of the lymphadenopathy and absence of new lesions. CONCLUSIONS: Immunosuppression is a major risk factor for development of malignancy in transplant recipients. Donor-derived malignancy can arise and current molecular studies allow an accurate diagnosis. Withdrawal of immunosuppression and surgical resection of the transplant kidney proved an effective treatment in our case.

ZEB1 Mediates Acquired Resistance to the Epidermal Growth Factor Receptor-Tyrosine Kinase Inhibitors in Non-Small Cell Lung Cancer.

Epithelial-mesenchymal transition (EMT) is one mechanism of acquired resistance to inhibitors of the epidermal growth factor receptor-tyrosine kinases (EGFR-TKIs) in non-small cell lung cancer (NSCLC). The precise mechanisms of EMT-related acquired resistance to EGFR-TKIs in NSCLC remain unclear. We generated erlotinib-resistant HCC4006 cells (HCC4006ER) by chronic exposure of EGFR-mutant HCC4006 cells to increasing concentrations of erlotinib. HCC4006ER cells acquired an EMT phenotype and activation of the TGF-ß/SMAD pathway, while lacking both T790M secondary EGFR mutation and MET gene amplification. We employed gene expression microarrays in HCC4006 and HCC4006ER cells to better understand the mechanism of acquired EGFR-TKI resistance with EMT. At the mRNA level, ZEB1 (TCF8), a known regulator of EMT, was >20-fold higher in HCC4006ER cells than in HCC4006 cells, and increased ZEB1 protein level was also detected. Furthermore, numerous ZEB1 responsive genes, such as CDH1 (E-cadherin), ST14, and vimentin, were coordinately regulated along with increased ZEB1 in HCC4006ER cells. We also identified ZEB1 overexpression and an EMT phenotype in several NSCLC cells and human NSCLC samples with acquired EGFR-TKI resistance. Short-interfering RNA against ZEB1 reversed the EMT phenotype and, importantly, restored erlotinib sensitivity in HCC4006ER cells. The level of micro-RNA-200c, which can negatively regulate ZEB1, was significantly reduced in HCC4006ER cells. Our results suggest that increased ZEB1 can drive EMT-related acquired resistance to EGFR-TKIs in NSCLC. Attempts should be made to explore targeting ZEB1 to resensitize TKI-resistant tumors.

Nivolumab in renal cell carcinoma.

INTRODUCTION: Immune-based therapies (e.g., IL-2, IFN) have been used for some time in advanced clear cell renal cell carcinoma (RCC) with overall modest success. Recent advances have demonstrated that tumor cells evade immune-mediated destruction by inducing inhibitory signals that result in effector T-cell exhaustion. One mechanism involves interaction between the T-cell programmed death-1 (PD-1) receptor and its ligand, PD ligand-1, expressed on tumor and inflammatory cells. Nivolumab , an anti-PD-1 antibody, blocks this pathway, thereby reversing T-cell suppression and activating antitumor responses. AREAS COVERED: In this review, the authors summarize selected aspects of PD-1 signaling, the development of immune checkpoint therapeutic agents, and clinical data regarding the safety and efficacy of nivolumab in RCC from Phase I and II clinical trials. EXPERT OPINION: Objective responses and safety profiles of single-agent nivolumab are favorable in patients with previously treated and treatment-naive metastatic RCC. Combination therapies involving nivolumab are ongoing and have generated encouraging results. The use of nivolumab will have substantial impact on the management of patients with RCC.

A Phase I/II Trial of BNC105P with Everolimus in Metastatic Renal Cell Carcinoma.

PURPOSE: BNC105P inhibits tubulin polymerization, and preclinical studies suggest possible synergy with everolimus. In this phase I/II study, efficacy and safety of the combination were explored in patients with metastatic renal cell carcinoma (mRCC). EXPERIMENTAL DESIGN: A phase I study in patients with clear cell mRCC and any prior number of therapies was conducted using a classical 3 + 3 design to evaluate standard doses of everolimus with increasing doses of BNC105P. At the recommended phase II dose (RP2D), patients with clear cell mRCC and one to two prior therapies (including ≥ 1 VEGF-TKI) were randomized to BNC105P with everolimus (arm A) or everolimus alone (arm B). The primary endpoint of the study was 6-month progression-free survival (6MPFS). Secondary endpoints included response rate, PFS, overall survival, and exploratory biomarker analyses. RESULTS: In the phase I study (N = 15), a dose of BNC105P at 16 mg/m(2) with everolimus at 10 mg daily was identified as the RP2D. In the phase II study, 139 patients were randomized, with 69 and 67 evaluable patients in arms A and B, respectively. 6MPFS was similar in the treatment arms (arm A: 33.82% vs. arm B: 30.30%, P = 0.66) and no difference in median PFS was observed (arm A: 4.7 mos vs. arm B: 4.1 mos; P = 0.49). Changes in matrix metalloproteinase-9, stem cell factor, sex hormone-binding globulin, and serum amyloid A protein were associated with clinical outcome with BNC105P. CONCLUSIONS: Although the primary endpoint was not met in an unselected population, correlative studies suggest several biomarkers that warrant further prospective evaluation.

Nivolumab for Metastatic Renal Cell Carcinoma: Results of a Randomized Phase II Trial.

PURPOSE: Nivolumab is a fully human immunoglobulin G4 programmed death-1 immune checkpoint inhibitor antibody that restores T-cell immune activity. This phase II trial assessed the antitumor activity, dose-response relationship, and safety of nivolumab in patients with metastatic renal cell carcinoma (mRCC). PATIENTS AND METHODS: Patients with clear-cell mRCC previously treated with agents targeting the vascular endothelial growth factor pathway were randomly assigned (blinded ratio of 1:1:1) to nivolumab 0.3, 2, or 10 mg/kg intravenously once every 3 weeks. The primary objective was to evaluate the dose-response relationship as measured by progression-free survival (PFS); secondary end points included objective response rate (ORR), overall survival (OS), and safety. RESULTS: A total of 168 patients were randomly assigned to the nivolumab 0.3- (n = 60), 2- (n = 54), and 10-mg/kg (n = 54) cohorts. One hundred eighteen patients (70%) had received more than one prior systemic regimen. Median PFS was 2.7, 4.0, and 4.2 months, respectively (P = .9). Respective ORRs were 20%, 22%, and 20%. Median OS was 18.2 months (80% CI, 16.2 to 24.0 months), 25.5 months (80% CI, 19.8 to 28.8 months), and 24.7 months (80% CI, 15.3 to 26.0 months), respectively. The most common treatment-related adverse event (AE) was fatigue (24%, 22%, and 35%, respectively). Nineteen patients (11%) experienced grade 3 to 4 treatment-related AEs. CONCLUSION: Nivolumab demonstrated antitumor activity with a manageable safety profile across the three doses studied in mRCC. No dose-response relationship was detected as measured by PFS. These efficacy and safety results in mRCC support study in the phase III setting.

Homeobox gene expression in acute myeloid leukemia is linked to typical underlying molecular aberrations.

BACKGROUND: Although distinct patterns of homeobox (HOX) gene expression have been described in defined cytogenetic and molecular subsets of patients with acute myeloid leukemia (AML), it is unknown whether these patterns are the direct result of transcriptional alterations or rather represent the differentiation stage of the leukemic cell. METHOD: To address this question, we used qPCR to analyze mRNA expression of HOXA and HOXB genes in bone marrow (BM) samples of 46 patients with AML and sorted subpopulations of healthy BM cells. These various stages of myeloid differentiation represent matched counterparts of morphological subgroups of AML. To further study the transcriptional alterations of HOX genes in hematopoiesis, we also analyzed gene expression of epigenetic modifiers in the subpopluations of healthy BM and leukemic cells. RESULTS: Unsupervised hierarchical clustering divided the AMLs into five clusters characterized by the presence of prevalent molecular genetic aberrations. Notably, the impact of genotype on HOX gene expression was significantly more pronounced than that of the differentiation stage of the blasts. This driving role of molecular aberrations was best exemplified by the repressive effect of the PML-RARa fusion gene on HOX gene expression, regardless of the presence of the FLT3/ITD mutation. Furthermore, HOX gene expression was positively correlated with mRNA levels of histone demethylases (JMJD3 and UTX) and negatively correlated with gene expression of DNA methyltranferases. No such relationships were observed in subpopulations of healthy BM cells. CONCLUSION: Our results demonstrate that specific molecular genetic aberrations, rather than differentiation per se, underlie the observed differences in HOX gene expression in AML. Moreover, the observed correlations between epigenetic modifiers and HOX expression that are specific to malignant hematopoiesis, suggest their potential causal relationships.

The emerging role of class-3 semaphorins and their neuropilin receptors in oncology.

The semaphorins, discovered over 20 years ago, are a large family of secreted or transmembrane and glycophosphatidylinositol -anchored proteins initially identified as axon guidance molecules crucial for the development of the nervous system. It has now been established that they also play important roles in organ development and function, especially involving the immune, respiratory, and cardiovascular systems, and in pathological disorders, including cancer. During tumor progression, semaphorins can have both pro- and anti-tumor functions, and this has created complexities in our understanding of these systems. Semaphorins may affect tumor growth and metastases by directly targeting tumor cells, as well as indirectly by interacting with and influencing cells from the micro-environment and vasculature. Mechanistically, semaphorins, through binding to their receptors, neuropilins and plexins, affect pathways involved in cell adhesion, migration, invasion, proliferation, and survival. Importantly, neuropilins also act as co-receptors for several growth factors and enhance their signaling activities, while class 3 semaphorins may interfere with this. In this review, we focus on the secreted class 3 semaphorins and their neuropilin co-receptors in cancer, including aspects of their signaling that may be clinically relevant.

Analysis of the t(3;8) of hereditary renal cell carcinoma: a palindrome-mediated translocation.

It has emerged that palindrome-mediated genomic instability generates DNA-based rearrangements. The presence of palindromic AT-rich repeats (PATRRs) at the translocation breakpoints suggested a palindrome-mediated mechanism in the generation of several recurrent constitutional rearrangements: the t(11;22), t(17;22), and t(8;22). To date, all reported PATRR-mediated translocations include the PATRR on chromosome 22 (PATRR22) as a translocation partner. Here, the constitutional rearrangement, t(3;8)(p14.2;q24.1), segregating with renal cell carcinoma in two families, is examined. The chromosome 8 breakpoint lies in PATRR8 in the first intron of the RNF139 (TRC8) gene, whereas the chromosome 3 breakpoint is located in an AT-rich palindromic sequence in intron 3 of the FHIT gene (PATRR3). Thus, the t(3;8) is the first PATRR-mediated, recurrent, constitutional translocation that does not involve PATRR22. Furthermore, we detect de novo translocations similar to the t(11;22) and t(8;22), involving PATRR3 in normal sperm. The breakpoint on chromosome 3 is in proximity to FRA3B, the most common fragile site in the human genome and a site of frequent deletions in tumor cells. However, the lack of involvement of PATRR3 sequence in numerous FRA3B-related deletions suggests that there are several different DNA sequence-based etiologies responsible for chromosome 3p14.2 genomic rearrangements.

A phase II trial of AS1411 (a novel nucleolin-targeted DNA aptamer) in metastatic renal cell carcinoma.

BACKGROUND: DNA aptamers represent a novel strategy in anti-cancer medicine. AS1411, a DNA aptamer targeting nucleolin (a protein which is overexpressed in many tumor types), was evaluated in patients with metastatic, clear-cell, renal cell carcinoma (RCC) who had failed treatment with ≥1 prior tyrosine kinase inhibitor. METHODS: In this phase II, single-arm study, AS1411 was administered at 40 mg/kg/day by continuous intravenous infusion on days 1-4 of a 28-day cycle, for two cycles. Primary endpoint was overall response rate; progression-free survival (PFS) and safety were secondary endpoints. RESULTS: 35 patients were enrolled and treated. One patient (2.9 %) had a response to treatment. The response was dramatic (84 % reduction in tumor burden by RECIST 1.0 criteria) and durable (patient remains free of progression 2 years after completing therapy). Whole exome sequencing of this patient's tumor revealed missense mutations in the mTOR and FGFR2 genes which is of interest because nucleolin is known to upregulate mTOR pathway activity by enhancing AKT1 mRNA translation. No other responses were seen. Thirty-four percent of patients had an AS1411-related adverse event, all of which were mild or moderate. CONCLUSIONS: AS1411 appears to have minimal activity in unselected patients with metastatic RCC. However, rare, dramatic and durable responses can be observed and toxicity is low. One patient in this study had an excellent response and was found to have FGFR2 and mTOR mutations which will be of interest in future efforts to discover and validate predictive biomarkers of response to nucleolin targeted compounds. DNA aptamers represent a novel way to target cancer cells at a molecular level and continue to be developed with a view to improving treatment and imaging in cancer medicine.

Global Decrease of Histone H3K27 Acetylation in ZEB1-Induced Epithelial to Mesenchymal Transition in Lung Cancer Cells.

The epithelial to mesenchymal transition (EMT) enables epithelial cells with a migratory mesenchymal phenotype. It is activated in cancer cells and is involved in invasion, metastasis and stem-like properties. ZEB1, an E-box binding transcription factor, is a major suppressor of epithelial genes in lung cancer. In the present study, we show that in H358 non-small cell lung cancer cells, ZEB1 downregulates EpCAM (coding for an epithelial cell adhesion molecule), ESRP1 (epithelial splicing regulatory protein), ST14 (a membrane associated serine protease involved in HGF processing) and RAB25 (a small G-protein) by direct binding to these genes. Following ZEB1 induction, acetylation of histone H4 and histone H3 on lysine 9 (H3K9) and 27 (H3K27) was decreased on ZEB1 binding sites on these genes as demonstrated by chromatin immunoprecipitation. Of note, decreased H3K27 acetylation could be also detected by western blot and immunocytochemistry in ZEB1 induced cells. In lung cancers, H3K27 acetylation level was higher in the tumor compartment than in the corresponding stroma where ZEB1 was more often expressed. Since HDAC and DNA methylation inhibitors increased expression of ZEB1 target genes, targeting these epigenetic modifications would be expected to reduce metastasis.

Neuropilin-2 Is upregulated in lung cancer cells during TGF-ß1-induced epithelial-mesenchymal transition.

The epithelial-mesenchymal transition (EMT) and its reversal, mesenchymal-epithelial transition (MET), are fundamental processes involved in tumor cell invasion and metastasis. SEMA3F is a secreted semaphorin and tumor suppressor downregulated by TGF-ß1 and ZEB1-induced EMT. Here, we report that neuropilin (NRP)-2, the high-affinity receptor for SEMA3F and a coreceptor for certain growth factors, is upregulated during TGF-ß1-driven EMT in lung cancer cells. Mechanistically, NRP2 upregulation was TßRI dependent and SMAD independent, occurring mainly at a posttranscriptional level involving increased association of mRNA with polyribosomes. Extracellular signal-regulated kinase (ERK) and AKT inhibition blocked NRP2 upregulation, whereas RNA interference-mediated attenuation of ZEB1 reduced steady-state NRP2 levels. In addition, NRP2 attenuation inhibited TGF-ß1-driven morphologic transformation, migration/invasion, ERK activation, growth suppression, and changes in gene expression. In a mouse xenograft model of lung cancer, NRP2 attenuation also inhibited locally invasive features of the tumor and reversed TGF-ß1-mediated growth inhibition. In support of these results, human lung cancer specimens with the highest NRP2 expression were predominantly E-cadherin negative. Furthermore, the presence of NRP2 staining strengthened the association of E-cadherin loss with high-grade tumors. Together, our results demonstrate that NRP2 contributes significantly to TGF-ß1-induced EMT in lung cancer.

Multiplexed specific label-free detection of NCI-H358 lung cancer cell line lysates with silicon based photonic crystal microcavity biosensors.

We experimentally demonstrate label-free photonic crystal (PC) microcavity biosensors in silicon-on-insulator (SOI) to detect the epithelial-mesenchymal transition (EMT) transcription factor, ZEB1, in minute volumes of sample. Multiplexed specific detection of ZEB1 in lysates from NCI-H358 lung cancer cells down to an estimated concentration of 2 cells per micro-liter is demonstrated. L13 photonic crystal microcavities, coupled to W1 photonic crystal waveguides, are employed in which resonances show high Q in the bio-ambient phosphate buffered saline (PBS). When the sensor surface is derivatized with a specific antibody, the binding of the corresponding antigen from a complex whole-cell lysate generates a change in refractive index in the vicinity of the photonic crystal microcavity, leading to a change in the resonance wavelength of the resonance modes of the photonic crystal microcavity. The shift in the resonance wavelength reveals the presence of the antigen. The sensor cavity has a surface area of ∼11µm(2). Multiplexed sensors permit simultaneous detection of many binding interactions with specific immobilized antibodies from the same bio-sample at the same instant of time. Specificity was demonstrated using a sandwich assay which further amplifies the detection sensitivity at low concentrations. The device represents a proof-of-concept demonstration of label-free, high throughput, multiplexed detection of cancer cells with specificity and sensitivity on a silicon chip platform.