Targeting RNA Exonuclease XRN1 Potentiates Efficacy of Cancer Immunotherapy

Despite the remarkable clinical responses achieved with immune checkpoint blockade therapy, the response rate is relatively low and only a subset of patients can benefit from the treatment. Aberrant RNA accumulation can mediate IFN signaling and stimulate an immune response, suggesting that targeting RNA decay machinery might sensitize tumor cells to immunotherapy. With this in mind, we identified an RNA exoribonuclease, XRN1, as a potential therapeutic target to suppress RNA decay and stimulate antitumor immunity. Silencing of XRN1 suppressed tumor growth in syngeneic immunocompetent mice and potentiated immunotherapy efficacy, while silencing of XRN1 alone did not affect tumor growth in immunodeficient mice. Mechanistically, XRN1 depletion activated IFN signaling and the viral defense pathway; both pathways play determinant roles in regulating immune evasion. Aberrant RNA-sensing signaling proteins (RIG-I/MAVS) mediated the expression of IFN genes, as depletion of each of them blunted the elevation of antiviral/IFN signaling in XRN1-silenced cells. Analysis of pan-cancer CRISPR-screening data indicated that IFN signaling triggered by XRN1 silencing is a common phenomenon, suggesting that the effect of XRN1 silencing may be extended to multiple types of cancers. Overall, XRN1 depletion triggers aberrant RNA-mediated IFN signaling, highlighting the importance of the aberrant RNA-sensing pathway in regulating immune responses. These findings provide the molecular rationale for developing XRN1 inhibitors and exploring their potential clinical application in combination with cancer immunotherapy.

SIGNIFICANCE

Targeting XRN1 activates an intracellular innate immune response mediated by RNA-sensing signaling and potentiates cancer immunotherapy efficacy, suggesting inhibition of RNA decay machinery as a novel strategy for cancer treatment.

CD19/CD20 bispecific chimeric antigen receptor (CAR) in naïve/memory T cells for the treatment of relapsed or refractory non-Hodgkin lymphoma

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Background: Although chimeric antigen receptor (CAR)-T cells produce impressive outcomes in B-cell malignancies, a substantial fraction of patients with relapsed/refractory B-cell leukemia and lymphoma treated with anti-CD19 CAR-T cell therapy (CART19) either do not respond to treatment or relapse, with poor CAR-T cell persistence or CD19 antigen escape being two key factors that limit durability of response. In order to address these factors, we initiated a clinical trial with naïve/memory T (TN/MEM) cells engineered to express bispecific anti-CD19/CD20 CARs (CART19/20) (NCT04007029). Methods: This trial is a Phase 1, first-in-human, dose-escalation trial enrolling patients with relapsed or refractory follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), mantle-cell lymphoma (MCL) and chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Following lymphodepletion chemotherapy with fludarabine and cyclophosphamide, patients received CART19/20 cell doses ranging from 50 x 106 to 200 x 106 CAR-positive cells. The primary endpoint was to evaluate the safety of CART19/20 as measured by adverse events and dose limiting toxicities. Secondary endpoints were efficacy as assessed by disease response, progression-free survival (PFS), overall survival (OS), and CAR transgene persistence. Results: As of February 7, 2022, dose-escalation has been completed with 9 patients enrolled and 8 patients infused (3 FL, 4 DLBCL including 2 transformed follicular and 1 primary mediastinal B cell, and 1 MCL). with CART19/20 cells on this study. The median age at the time of CART19/20 infusion was 59 and median prior lines of therapy was 3.5. All patients had stage IV disease and 7 of 9 patients required bridging therapy. Grade-1 cytokine release syndrome (CRS) occurred in 6 of 8 patients, and no patient experienced immune effector cell-associated neurotoxicity syndrome ( ICANS). Among all patients, only one dose of tocilizumab was administered to one subject, and no steroids were given. With a median follow-up of 12 months from time of CART19/20 infusion (range: 4+ to 24+ months), 7 of 8 of patients remain in a complete remission. Median PFS and OS were not reached, and all patients with a complete remission demonstrate ongoing B-cell aplasia. Conclusions: This study demonstrates that CART19/20 cells are safe and effective in patients with relapsed/refractory NHL and potentially obviates the challenges of the commonest causes of relapse after CAR-T cell therapy by means of modifying TN/MEM cells and dual-antigen targeting, respectively. Given the strong safety and response observed, dose escalation was completed with the second dosing level (DL2) of 200 x 106 CAR-positive cells, and DL1 of 50 x 106 CAR-positive cells was chosen as the therapeutic dose for future trial expansion. Clinical trial information: NCT04007029.

HIV, pathology and epigenetic age acceleration in different human tissues

Epigenetic clocks based on patterns of DNA methylation have great importance in understanding aging and disease; however, there are basic questions to be resolved in their application. It remains unknown whether epigenetic age acceleration (EAA) within an individual shows strong correlation between different primary tissue sites, the extent to which tissue pathology and clinical illness correlate with EAA in the target organ, and if EAA variability across tissues differs according to sex. Considering the outsized role of age-related illness in Human Immunodeficiency Virus-1 (HIV), these questions were pursued in a sample enriched for tissue from HIV-infected individuals. We used a custom methylation array to generate DNA methylation data from 661 samples representing 11 human tissues (adipose, blood, bone marrow, heart, kidney, liver, lung, lymph node, muscle, spleen and pituitary gland) from 133 clinically characterized, deceased individuals, including 75 infected with HIV. We developed a multimorbidity index based on the clinical disease history. Epigenetic age was moderately correlated across tissues. Blood had the greatest number and degree of correlation, most notably with spleen and bone marrow. However, blood did not correlate with epigenetic age of liver. EAA in liver was weakly correlated with EAA in kidney, adipose, lung and bone marrow. Clinically, hypertension was associated with EAA in several tissues, consistent with the multiorgan impacts of this illness. HIV infection was associated with positive age acceleration in kidney and spleen. Male sex was associated with increased epigenetic acceleration in several tissues. Preliminary evidence indicates that amyotrophic lateral sclerosis is associated with positive EAA in muscle tissue. Finally, greater multimorbidity was associated with greater EAA across all tissues. Blood alone will often fail to detect EAA in other tissues. While hypertension is associated with increased EAA in several tissues, many pathologies are associated with organ-specific age acceleration.

CD70 is a promising CAR-T cell target in patients with advanced renal cell carcinoma

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Background: Renal cell carcinoma (RCC) comprises a heterogeneous group of tumors of different histological subtypes. Each subtype is characterized by distinct immunohistochemical and molecular features and different biology. Currently, patients with advanced RCC have poor disease outcomes despite recent breakthroughs in immunotherapy. Chimeric antigen receptor (CAR)-T cell therapy has produced remarkably effective and durable clinical responses in hematological malignancies. However, there have been very limited success of CAR-T cell therapy in solid tumors. CD70 and its signaling partner CD27 are cell surface molecules that have emerged as novel targets for immune modulation approach. CD70 is also a promising target for CAR-T cell therapy, as it is overexpressed on multiple types of solid tumors including RCC and not expressed in most normal tissue. Studies have shown clear cell RCC (CCRCC) commonly expresses CD70. To date, no studies has evaluated CD70 expression in metastatic RCC in comparison with primary RCC. Methods: Four Tissue Microarrays (TMAs) were constructed using 395 tumors from 374 patients with RCC, 4 to 8 cores per tumor. There were 359 primary tumors, 36 metastatic tumors, and 344 matched normal. The primary RCC included 309 CCRCC including 11 with sarcomatoid differentiation, 38 papillary RCC (pRCC) including 1 with sarcomatoid differentiation, 8 chromophobe RCC (ChRCC), and 4 collecting duct RCC (CDC). The metastatic RCC were composed of 31 CCRCC including 3 with sarcomatoid differentiation and 5 PRCC. CD70 expression was evaluated using immunohistochemistry (IHC) and Definiens image analysis. CD70 expression was measured using the percentage of CD70-positive tumor cells. A CD70-positive tumor was defined as CD70 immunopercentage ≥ cutoff value in at least one core. Results: CD70 staining was detected in tumor cells in primary and metastatic RCC, with minimal staining in normal renal parenchyma. When the positive cutoff was defined as ≥1% of tumor cells demonstrating CD70 staining, the positive rate in CCRCC, pRCC, ChRCC, CDC, and SarRCC was 98%, 32%, 0%, 11%, and 46%, respectively. When the positive cutoff was defined as ≥ 25% of tumor cells stained positive for CD70, the positive rate in CCRCC, pRCC, ChRCC, CDC, and SarRCC was 41%, 10%, 0%, 0%, and 23%, respectively. Finally, when the positive cutoff was defined as ≥50%, the positive rate in CCRCC, pRCC, ChRCC, CDC, and SarRCC was 22%, 2%, 0%, 0%, and 8%, respectively. Metastatic RCC showed a higher % of tumor cells expressing CD70 compared to primary RCC for patients with CCRCC (mean 15% vs 9%) or SarRCC (12% vs 9%). Conclusions: Clear cell and sarcomatoid RCC are the RCC subtypes that demonstrate the highest CD70 expression. CD70 expression is further increased in metastatic lesions compared to the primary tumors. Anti-CD70 CAR-T cell therapy may benefit a significant fraction of patients with advanced CCRCC and sarcomatoid RCC.

Biomarkers for Risk Stratification in Patients With Previously Untreated Follicular Lymphoma Receiving Anti-CD20-based Biological Therapy

Follicular lymphoma (FL) is an indolent B-cell neoplasm of germinal center origin. Standard treatment regimens consist of anti-CD20 therapy with or without chemotherapy. While high response rates to initial therapy are common, patients ultimately relapse or have progressive disease. Clinical risk factors such as the Follicular Lymphoma International Prognostic Index (FLIPI) have been identified, but there is a need for prognostic and predictive biomarkers. We studied markers of lymphoma cells and tumor microenvironment by immunohistochemistry in tissue samples from patients enrolled in 1 of 4 phase 2 trials of anti-CD20-based biological therapy for previously untreated grades 1 to 2 or 3A FL. Results were correlated with progression-free survival (PFS) and PFS status at 24 months. The 4 trials included 238 patients (51.1% male, median age: 55 y) with stage III, IV, or bulky stage II disease. By FLIPI, 24.6% had low-risk, 56.8% had intermediate-risk, and 18.6% had high-risk disease. The outcome differed significantly for patients treated with lenalidomide and rituximab (CALGB 50803) compared with the other 3 trials (median: PFS not reached vs. 3.0 y, hazard ratio=3.47, 95% confidence interval: 2.11-5.72); therefore, data were stratified by clinical trial (CALGB 50803 vs. all others) and adjusted for FLIPI risk group. Among 154 patients with available tissue, interfollicular BCL6 positivity, interfollicular CD10 positivity, and elevated Ki67 proliferation index ≥30% within neoplastic follicles were each associated with inferior PFS and a high risk of the early event by PFS status at 24 months. We identify promising biomarkers for FL risk stratification that warrant further validation in phase 3 trials.

TP63, SOX2, and KLF5 Establish a Core Regulatory Circuitry That Controls Epigenetic and Transcription Patterns in Esophageal Squamous Cell Carcinoma Cell Lines

BACKGROUND & AIMS

We investigated the transcriptome of esophageal squamous cell carcinoma (ESCC) cells, activity of gene regulatory (enhancer and promoter regions), and the effects of blocking epigenetic regulatory proteins.

METHODS

We performed chromatin immunoprecipitation sequencing with antibodies against H3K4me1, H3K4me3, and H3K27ac and an assay for transposase-accessible chromatin to map the enhancer regions and accessible chromatin in 8 ESCC cell lines. We used the CRC_Mapper algorithm to identify core regulatory circuitry transcription factors in ESCC cell lines, and determined genome occupancy profiles for 3 of these factors. In ESCC cell lines, expression of transcription factors was knocked down with small hairpin RNAs, promoter and enhancer regions were disrupted by CRISPR/Cas9 genome editing, or bromodomains and extraterminal (BET) family proteins and histone deacetylases (HDACs) were inhibited with ARV-771 and romidepsin, respectively. ESCC cell lines were then analyzed by whole-transcriptome sequencing, immunoprecipitation, immunoblots, immunohistochemistry, and viability assays. Interactions between distal enhancers and promoters were identified and verified with circular chromosome conformation capture sequencing. NOD-SCID mice were given injections of modified ESCC cells, some mice where given injections of HDAC or BET inhibitors, and growth of xenograft tumors was measured.

RESULTS

We identified super-enhancer-regulated circuits and transcription factors TP63, SOX2, and KLF5 as core regulatory factors in ESCC cells. Super-enhancer regulation of ALDH3A1 mediated by core regulatory factors was required for ESCC viability. We observed direct interactions between the promoter region of TP63 and functional enhancers, mediated by the core regulatory circuitry transcription factors. Deletion of enhancer regions from ESCC cells decreased expression of the core regulatory circuitry transcription factors and reduced cell viability; these same results were observed with knockdown of each core regulatory circuitry transcription factor. Incubation of ESCC cells with BET and HDAC disrupted the core regulatory circuitry program and the epigenetic modifications observed in these cells; mice given injections of HDAC or BET inhibitors developed smaller xenograft tumors from the ESCC cell lines. Xenograft tumors grew more slowly in mice given the combination of ARV-771 and romidepsin than mice given either agent alone.

CONCLUSIONS

In epigenetic and transcriptional analyses of ESCC cell lines, we found the transcription factors TP63, SOX2, and KLF5 to be part of a core regulatory network that determines chromatin accessibility, epigenetic modifications, and gene expression patterns in these cells. A combination of epigenetic inhibitors slowed growth of xenograft tumors derived from ESCC cells in mice.

Master transcription factors form interconnected circuitry and orchestrate transcriptional networks in oesophageal adenocarcinoma

OBJECTIVE

While oesophageal squamous cell carcinoma remains infrequent in Western populations, the incidence of oesophageal adenocarcinoma (EAC) has increased sixfold to eightfold over the past four decades. We aimed to characterise oesophageal cancer-specific and subtypes-specific gene regulation patterns and their upstream transcription factors (TFs).  DESIGN: To identify regulatory elements, we profiled fresh-frozen oesophageal normal samples, tumours and cell lines with chromatin immunoprecipitation sequencing (ChIP-Seq). Mathematical modelling was performed to establish (super)-enhancers landscapes and interconnected transcriptional circuitry formed by master TFs. Coregulation and cooperation between master TFs were investigated by ChIP-Seq, circularised chromosome conformation capture sequencing and luciferase assay. Biological functions of candidate factors were evaluated both in vitro and in vivo.

RESULTS

We found widespread and pervasive alterations of the (super)-enhancer reservoir in both subtypes of oesophageal cancer, leading to transcriptional activation of a myriad of novel oncogenes and signalling pathways, some of which may be exploited pharmacologically (eg, leukemia inhibitory factor (LIF) pathway). Focusing on EAC, we bioinformatically reconstructed and functionally validated an interconnected circuitry formed by four master TFs-ELF3, KLF5, GATA6 and EHF-which promoted each other's expression by interacting with each super-enhancer. Downstream, these master TFs occupied almost all EAC super-enhancers and cooperatively orchestrated EAC transcriptome. Each TF within the transcriptional circuitry was highly and specifically expressed in EAC and functionally promoted EAC cell proliferation and survival.

CONCLUSIONS

By establishing cancer-specific and subtype-specific features of the EAC epigenome, our findings promise to transform understanding of the transcriptional dysregulation and addiction of EAC, while providing molecular clues to develop novel therapeutic modalities against this malignancy.

RNA-Binding Protein ZFP36L1 Suppresses Hypoxia and Cell-Cycle Signaling

ZFP36L1 is a tandem zinc-finger RNA-binding protein that recognizes conserved adenylate-uridylate-rich elements (ARE) located in 3'untranslated regions (UTR) to mediate mRNA decay. We hypothesized that ZFP36L1 is a negative regulator of a posttranscriptional hub involved in mRNA half-life regulation of cancer-related transcripts. Analysis of in silico data revealed that ZFP36L1 was significantly mutated, epigenetically silenced, and downregulated in a variety of cancers. Forced expression of ZFP36L1 in cancer cells markedly reduced cell proliferation in vitro and in vivo, whereas silencing of ZFP36L1 enhanced tumor cell growth. To identify direct downstream targets of ZFP36L1, systematic screening using RNA pull-down of wild-type and mutant ZFP36L1 as well as whole transcriptome sequencing of bladder cancer cells {plus minus} tet-on ZFP36L1 was performed. A network of 1,410 genes was identified as potential direct targets of ZFP36L1. These targets included a number of key oncogenic transcripts such as HIF1A, CCND1, and E2F1. ZFP36L1 specifically bound to the 3'UTRs of these targets for mRNA degradation, thus suppressing their expression. Dual luciferase reporter assays and RNA electrophoretic mobility shift assays showed that wild-type, but not zinc-finger mutant ZFP36L1, bound to HIF1A 3'UTR and mediated HIF1A mRNA degradation, leading to reduced expression of HIF1A and its downstream targets. Collectively, our findings reveal an indispensable role of ZFP36L1 as a posttranscriptional safeguard against aberrant hypoxic signaling and abnormal cell-cycle progression. SIGNIFICANCE: RNA-binding protein ZFP36L1 functions as a tumor suppressor by regulating the mRNA stability of a number of mRNAs involved in hypoxia and cell-cycle signaling.

Super-enhancer-associated MEIS1 promotes transcriptional dysregulation in Ewing sarcoma in co-operation with EWS-FLI1

As the second most common malignant bone tumor in children and adolescents, Ewing sarcoma is initiated and exacerbated by a chimeric oncoprotein, most commonly, EWS-FLI1. In this study, we apply epigenomic analysis to characterize the transcription dysregulation in this cancer, focusing on the investigation of super-enhancer and its associated transcriptional regulatory mechanisms. We demonstrate that super-enhancer-associated transcripts are significantly enriched in EWS-FLI1 target genes, contribute to the aberrant transcriptional network of the disease, and mediate the exceptional sensitivity of Ewing sarcoma to transcriptional inhibition. Through integrative analysis, we identify MEIS1 as a super-enhancer-driven oncogene, which co-operates with EWS-FLI1 in transcriptional regulation, and plays a key pro-survival role in Ewing sarcoma. Moreover, APCDD1, another super-enhancer-associated gene, acting as a downstream target of both MEIS1 and EWS-FLI1, is also characterized as a novel tumor-promoting factor in this malignancy. These data delineate super-enhancer-mediated transcriptional deregulation in Ewing sarcoma, and uncover numerous candidate oncogenes which can be exploited for further understanding of the molecular pathogenesis for this disease.

LNK suppresses interferon signaling in melanoma

LNK (SH2B3) is a key negative regulator of JAK-STAT signaling which has been extensively studied in malignant hematopoietic diseases. We found that LNK is significantly elevated in cutaneous melanoma; this elevation is correlated with hyperactive signaling of the RAS-RAF-MEK pathway. Elevated LNK enhances cell growth and survival in adverse conditions. Forced expression of LNK inhibits signaling by interferon-STAT1 and suppresses interferon (IFN) induced cell cycle arrest and cell apoptosis. In contrast, silencing LNK expression by either shRNA or CRISPR-Cas9 potentiates the killing effect of IFN. The IFN-LNK signaling is tightly regulated by a negative feedback mechanism; melanoma cells exposed to IFN upregulate expression of LNK to prevent overactivation of this signaling pathway. Our study reveals an unappreciated function of LNK in melanoma and highlights the critical role of the IFN-STAT1-LNK signaling axis in this potentially devastating disease. LNK may be further explored as a potential therapeutic target for melanoma immunotherapy.

LNK is a tumor suppressor in hematopoietic cancers, but its function in melanoma is unclear. Here, the authors show that the overexpression of LNK in melanomas correlate with hyperactive signaling of the RAS-RAF-MEK pathway and LNK enhances melanoma growth and survival and immune evasion by inhibiting IFN signalling.

ASXL2 regulates hematopoiesis in mice and its deficiency promotes myeloid expansion

Chromosomal translocation t(8;21)(q22;q22) which leads to the generation of oncogenic RUNX1-RUNX1T1 (AML1-ETO) fusion is observed in approximately 10% of acute myelogenous leukemia (AML). To identify somatic mutations that co-operate with t(8;21)-driven leukemia, we performed whole and targeted exome sequencing of an Asian cohort at diagnosis and relapse. We identified high frequency of truncating alterations in ASXL2 along with recurrent mutations of KIT, TET2, MGA, FLT3, and DHX15 in this subtype of AML. To investigate in depth the role of ASXL2 in normal hematopoiesis, we utilized a mouse model of ASXL2 deficiency. Loss of ASXL2 caused progressive hematopoietic defects characterized by myeloid hyperplasia, splenomegaly, extramedullary hematopoiesis, and poor reconstitution ability in transplantation models. Parallel analyses of young and >1-year old Asxl2-deficient mice revealed age-dependent perturbations affecting, not only myeloid and erythroid differentiation, but also maturation of lymphoid cells. Overall, these findings establish a critical role for ASXL2 in maintaining steady state hematopoiesis, and provide insights into how its loss primes the expansion of myeloid cells.

The c-MYC-BMI1 axis is essential for SETDB1-mediated breast tumourigenesis

Characterising the activated oncogenic signalling that leads to advanced breast cancer is of clinical importance. Here, we showed that SET domain, bifurcated 1 (SETDB1), a histone H3 lysine 9 methyltransferase, is aberrantly expressed and behaves as an oncogenic driver in breast cancer. SETDB1 enhances c-MYC and cyclin D1 expression by promoting the internal ribosome entry site (IRES)-mediated translation of MYC/CCND1 mRNA, resulting in prominent signalling of c-MYC to promote cell cycle progression, and provides a growth/self-renewal advantage to breast cancer cells. The activated c-MYC-BMI1 axis is essential for SETDB1-mediated breast tumourigenesis, because silencing of either c-MYC or BMI1 profoundly impairs the enhanced growth/colony formation conferred by SETDB1. Furthermore, c-MYC directly binds to the SETDB1 promoter region and enhances its transcription, suggesting a positive regulatory interplay between SETDB1 and c-MYC. In this study, we identified SETDB1 as a prominent oncogene and characterised the underlying mechanism whereby SETDB1 drives breast cancer, providing a therapeutic rationale for targeting SETDB1-BMI1 signalling in breast cancer. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

A phase I, open-label, dose-escalation and cohort expansion study evaluating the safety and immune response to autologous dendritic cells transduced with AdGMCA9 in patients with metastatic renal cell carcinoma

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Background: We developed a fusion gene construct, GM-CSF + CAIX, transduced by a replication deficient adenovirus into autologous dendritic cells (DC) that are injected in patients with metastatic RCC (mRCC) in this phase 1 study targeting CAIX overexpressed on RCC tumors. Methods: A recombinant adenovirus encoding the GMCSF-CAIX fusion gene (AdGMCAIX) manufactured per GMP in collaboration with the NCI Rapid Access to Intervention Development (RAID) program. The final product was produced using DCs produced ex-vivo from patients’ peripheral blood mononuclear cells (PBMC), by culturing with GM-CSF & IL-4, then engineered with AdGMCAIX prior to intradermal injection. The injected transduced DCs were expected to stimulate an antigen specific immune response against CAIX expressing RCC. Three dose escalation cohorts (5, 15, and 50 X 106 cells/administration) were injected based on 3+3 design. DC-AdGMCAIX was given intradermally q2wkX3 doses. The primary aim is safety. Secondary aims are to evaluate immune responses & antitumor effects per RECIST 1.1. Eligibility criteria included patients with clear cell mRCC with ECOG 0-1, measurable disease, and adequate organ function. Results: Fifteen patients with clear cell mRCC were enrolled. Nine patients received all 3 planned vaccine doses, comprising DC expressing CAIX, CD11c and other relevant markers. No serious adverse events (SAEs) were seen. Grade 1/2 AEs include fatigue (3/1), leukopenia (1/1) and flu-like symptoms (0/1). Of the 9 patients who received treatment, 1 expired of progressive disease (PD), 2 patients were lost to follow-up and 6 patients are alive. Of the 6 patients, 5 have PD and are currently receiving standard-of-care therapies, and 1 has completed treatment with stable disease at 6 mon follow up and is being evaluated for retreatment. Conclusions: These early data show that autologous DC transduced by Ad-GMCAIX vector can be safely given to mRCC patients without any SAEs noted at the doses tested. These data support further development of Ad-GMCAIX vaccine strategies, either alone, or in combination with approved therapies. Clinical trial information: NCT01826877.

Circadian clock cryptochrome proteins regulate autoimmunity

The circadian system regulates numerous physiological processes including immune responses. Here, we show that mice deficient of the circadian clock genes Cry1 and Cry2 [Cry double knockout (DKO)] develop an autoimmune phenotype including high serum IgG concentrations, serum antinuclear antibodies, and precipitation of IgG, IgM, and complement 3 in glomeruli and massive infiltration of leukocytes into the lungs and kidneys. Flow cytometry of lymphoid organs revealed decreased pre-B cell numbers and a higher percentage of mature recirculating B cells in the bone marrow, as well as increased numbers of B2 B cells in the peritoneal cavity of Cry DKO mice. The B cell receptor (BCR) proximal signaling pathway plays a critical role in autoimmunity regulation. Activation of Cry DKO splenic B cells elicited markedly enhanced tyrosine phosphorylation of cellular proteins compared with cells from control mice, suggesting that overactivation of the BCR-signaling pathway may contribute to the autoimmunity phenotype in the Cry DKO mice. In addition, the expression of C1q, the deficiency of which contributes to the pathogenesis of systemic lupus erythematosus, was significantly down-regulated in Cry DKO B cells. Our results suggest that B cell development, the BCR-signaling pathway, and C1q expression are regulated by circadian clock CRY proteins and that their dysregulation through loss of CRY contributes to autoimmunity.

Kinase profiling of liposarcomas using RNAi and drug screening assays identified druggable targets

BACKGROUND

Liposarcoma, the most common soft tissue tumor, is understudied cancer, and limited progress has been made in the treatment of metastatic disease. The Achilles heel of cancer often is their kinases that are excellent therapeutic targets. However, very limited knowledge exists of therapeutic critical kinase targets in liposarcoma that could be potentially used in disease management.

METHODS

Large RNAi and small-molecule tyrosine kinase inhibitor screens were performed against the proliferative capacity of liposarcoma cell lines of different subtypes. Each small molecule inhibitor was either FDA approved or in a clinical trial.

RESULTS

Screening assays identified several previously unrecognized targets including PTK2 and KIT in liposarcoma. We also observed that ponatinib, multi-targeted tyrosine kinase inhibitor, was the most effective drug with anti-growth effects against all cell lines. In vitro assays showed that ponatinib inhibited the clonogenic proliferation of liposarcoma, and this anti-growth effect was associated with apoptosis and cell cycle arrest at the G0/G1 phase as well as a decrease in the KIT signaling pathway. In addition, ponatinib inhibited in vivo growth of liposarcoma in a xenograft model.

CONCLUSIONS

Two large-scale kinase screenings identified novel liposarcoma targets and a FDA-approved inhibitor, ponatinib with clear anti-liposarcoma activity highlighting its potential therapy for treatment of this deadly tumor.

Selinexor (KPT-330) has antitumor activity against anaplastic thyroid carcinoma in vitro and in vivo and enhances sensitivity to doxorubicin

Anaplastic thyroid carcinoma (ATC) is one of the most lethal malignancies having no effective treatment. Exportin-1 (XPO1) is the key mediator of nuclear export of many tumor suppressor proteins and is overexpressed in human cancers. In this study, we examined the therapeutic potential of selinexor (XPO1 inhibitor) against human ATC cells both in vitro and in vivo. Here, we showed that XPO1 is robustly expressed in primary ATC samples and human ATC cell lines. Silencing of XPO1 by either shRNA or selinexor significantly reduced cellular growth and induced cell cycle arrest, apoptosis of ATC cells by altering the protein expression of cancer-related genes. Moreover, selinexor significantly inhibited tumor growth of ATC xenografts. Microarray analysis showed enrichment of DNA replication, cell cycle, cell cycle checkpoint and TNF pathways in selinexor treated ATC cells. Importantly, selinexor decreased AXL and GAS6 levels in CAL62 and HTH83 cells and suppressed the phosphorylation of downstream targets of AXL signaling such as AKT and P70S6K. Finally, a combination of selinexor with doxorubicin demonstrated a synergistic decrease in the cellular proliferation of several ATC cells. These results provide a rationale for investigating the efficacy of combining selinexor and doxorubicin therapy to improve the outcome of ATC patients.

Abstract 4188: Multitargeted tyrosine kinase inhibitor identified as potential therapeutic intervention for liposarcoma using high-throughput profiling

Liposarcoma is a rare fat cell adult tumor with high risk of recurrence and metastasis, largely underserved by research community and till now limited progress has been made in treatment of this aggressive disease. We used a strategy to identify effective and potential therapeutic kinase inhibitors, irrespective of the activated kinase pathway, using small molecule kinase inhibitor panel. We screened liposarcoma cell lines of different histotypes to a panel of small molecule kinase inhibitors and analyzed using cell proliferation assay. In vitro cell proliferation assay, colony formation, cell cycle analysis, apoptosis assay and western blotting analysis were performed to investigate the effect and mechanism of inhibitor treatment on liposarcoma. Liposarcoma xenograft model system was also employed to investigate anti-tumor in vivo effects of inhibitor treatment. We observed that cell lines demonstrated diverse in vitro drug sensitivity patterns to various kinase inhibitors. Most of the cell lines showed very high sensitivity towards inhibitors targeting proteasome, protein kinase C, Hsp90, PI3K, mTOR and CDKs. Among the receptor tyrosine kinase inhibitors; Ponatinib, Dasatinib, and Sunitinib are the top most sensitive drugs affecting liposarcoma cells lines’ viability irrespective of subtypes and all these are already approved by the U.S. Food and Drug Administration to treat various cancers. We studied multi-targeted tyrosine kinase inhibitor ponatinib as an effective potential drug molecule in liposarcoma. We demonstrated that ponatinib treatment in liposarcoma cell lines reduced the levels of phosphorylated KIT compared to total KIT protein levels in dose dependent manner. Further, western blotting experiments revealed effect of ponatinib treatment on KIT downstream signalling by inhibiting the phosphorylation of AKT, ERK1/2, STAT3, mTOR, P70S6K and RB without affecting their total protein levels. Significant reduction in cell number and colonies with ponatinib treatment implicates anti-neoplastic effects in liposarcoma. Ponatinib treatment causes cell cycle arrest at G0/G1 phase by regulating CDK4 and cyclinD1 proteins levels. It also induces apoptosis of treated cells by downregulating AKT and ERK signaling pathway leading to dephosphorylation of BAD. Similar growth inhibiting effect of ponatinib was demonstrated in in vivo liposarcoma xenograft model. In vitro drug sensitivity profiling of liposarcoma highlighted Ponatinib, an oral FDA approved drug, as potential therapeutic drug candidate for treatment and management of this deadly tumor.

Citation Format: Deepika Kanojia, Manoj Garg, Jakki Martinez, Anand M.T., Samuel B Luty, Ngan B Doan, Jonathan W Said, Jeffrey W Tyner, H Phillip Koeffler. Multitargeted tyrosine kinase inhibitor identified as potential therapeutic intervention for liposarcoma using high-throughput profiling [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 4188. doi:10.1158/1538-7445.AM2017-4188

Abstract 2569: BCL6 promotes glioma and serves as a novel therapeutic target

ZBTB transcription factors orchestrate gene transcription during tissue development. However, their roles in glioblastoma multiforme (GBM) remain unexplored. Here, through a functional screening of ZBTB genes, we identify that BCL6 is required for GBM cell proliferation and is overexpressed in GBM samples. Using a somatic transgenic mouse model, Bcl6 confers the proliferative and invasive stimuli to glioma cells in vivo. Moreover, we discover AXL as a novel downstream target of BCL6. Through AXL, BCL6 enhances both MEK-ERK and S6K-RPS6 axes. Pharmacological inhibition of BCL6 activity effectively blocks GBM growth and inhibits AXL expression. Together, these findings uncover a novel glioma-promoting role of BCL6, and provide the rationale of targeting BCL6 as a potential therapeutic approach.

Citation Format: Liang Xu, Ye CHEN, Marina Dutra-Clarke, Anand Mayakonda, Masaharu Hazawa, Steve E. Savinoff, Ngan Doan, Jonathan W. Said, William H. Yong, Henry Yang, Ling-Wen Ding, Yan-Yi Jiang, Jeffrey W. Tyner, Jianhong Ching, Jean-Paul Kovalik, Markus Müschen, Joshua J. Breunig, De-Chen Lin, Phillip Koeffler. BCL6 promotes glioma and serves as a novel therapeutic target [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 2569. doi:10.1158/1538-7445.AM2017-2569

Abstract 1524: BCL6 modulates the TP53 and STAT pathways in glioma

Glioblastoma multiforme (GBM) remains the most aggressive brain malignancy with little improvement in prognosis or therapy for decades. Recently, we identified BCL6, also known as ZBTB27, to be a novel oncogene in GBM. In this study, we performed IHC analysis of 153 primary human glioma specimens and 8 normal brain samples. BCL6 expression is robustly elevated in tumor samples and positively correlated with glioma pathological grade. High BCL6 expression strongly predicts a worse prognosis of GBM patients. Depletion of BCL6 in human GBM cells reduced the incorporation of BrdU, promoted the cellular senescence and inhibited the growth of human GBM cells in vivo. Next, genome-wide occupancy of BCL6 in GBM cells was characterized by ChIP-seq assay. Genomic regions centered on BCL6 peaks are co-enriched with RNA-Pol II and flanked with strong H3K27ac and H3K4me3 modifications. MYC and two long non-coding RNAs MALAT1 and NEAT1 were identified as novel BCL6 targets in GBM. Moreover, pathway enrichment analysis of BCL6 peak-associated genes reveals a significant enrichment of JAK-STAT, TP53, ERBB and MAPK pathways. We demostrated further that BCL6 represses the TP53 pathway and promotes the JAK-STAT pathway activation in GBM cells. Together, our findings uncover potential downstream targets and provide a better understanding of BCL6 function in GBM.

Citation Format: Ye Chen, Liang Xu, Marina Dutra-Clarke, Anand Mayakonda, De-Chen Lin, Lynnette Koh, Yuk Kien Chong, Edwin Sandanaraj, Vikas Madan, Henry Yang, Ngan Doan, Jonathan W. Said, William H. Yong, Markus Müschen, Beng Ti Ang, Carol Tang, Joshua J. Breunig, Phillip Koeffler. BCL6 modulates the TP53 and STAT pathways in glioma [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 1524. doi:10.1158/1538-7445.AM2017-1524

A 17-gene panel for prediction of adverse surgical pathology in the setting of MRI-guided prostate biopsy

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Background: A 17 gene panel (Oncotype Dx Genomic Prostate Score, GPS) has been validated as an independent predictor of adverse pathology (AP, defined as pathological GS 4+3 or higher and/or pT3+) in men treated with radical prostatectomy (RP) for prostate cancer (PCa). Multiparametric Magnetic Resonance Imaging (mpMRI) may help guide prostate biopsies. We explored synergies between GPS and mpMRI to aid in PCa management decisions. Methods: A cohort of men with NCCN Low and Intermediate-Risk PCa who were managed with RP was identified from a clinical database. Patients were required to have had a simultaneous mpMRI-guided and systematic biopsy and to have undergone RP within 6 months. Biopsy tissue of the highest Gleason pattern was used for calculation of GPS. The primary endpoint was AP. Secondary endpoints included the range of GPS within UCLA prostate MRI risk groups and median GPS when there was discrepancy between MRI and systematic biopsy Gleason Score (GS). Logistic regression models were fit to evaluate the relationship between GPS (per 20 units) and AP. Results: 134 men met criteria for the primary endpoint. Median age was 62 years (range 46-77). NCCN Low & Intermediate-Risk PCa was present in 16%, and 84% of men, respectively. Biopsy GS 3+3/3+4/4+3 was present in 19%, 67%, and 13%, respectively. In a univariable model, GPS was associated with AP (OR 3.8, 95% CI 2.1 to 7.4, p < 0.001). After adjustment for highest biopsy GS and clinical T-stage, GPS remained significantly associated with AP (OR 3.4, 95% CI 1.8 to 6.8, p = 0.0004). A wide and overlapping distribution of GPS was noted across UCLA MRI prostate risk groups, indicating that GPS provides information that is distinct from what can be determined from mpMRI. When there was a discrepancy between mpMRI and systematic biopsy GS, mpMRI targeted lesions with higher GS had higher median GPS (33, range 13-70) than systematic biopsies with higher GS (median GPS 25, range 15-55). Conclusions: GPS provides independent and complementary prognostic information to mpMRI-guided biopsies. The combination of mpMRI for biopsy guidance and GPS for molecular analysis may optimize prediction of AP and improve patient selection for treatment versus surveillance.

Radiotherapy versus radical prostatectomy for Gleason score 9-10 prostate adenocarcinoma: A multi-institutional comparative analysis of 1001 patients treated in the modern era

7

Background: To compare the outcomes of a modern cohort of patients with Gleason Score (GS) 9-10 prostate adenocarcinoma (CaP) following treatment with external beam radiotherapy (EBRT), extremely dose-escalated radiotherapy (as exemplified by EBRT with a brachytherapy boost [EBRT+BT]), and radical prostatectomy (RP). Methods: One-thousand-and-one patients with biopsy GS 9-10 CaP who received definitive treatment between 2000 and 2013 were included (347 treated with EBRT, 330 with EBRT+BT, and 324 with RP). Kaplan-Meier analysis and multivariate Cox regression compared 5- and 10-year rates of distant metastasis-free survival (DMFS), cancer-specific survival (CSS), and overall survival (OS). Prostate cancer-mortality (PCSM) rates were compared with a competing risk analysis. Results: The median followup periods were 4.8, 6.4, and 5.1 years among patients receiving EBRT, EBRT + BT, and RP. The median doses among EBRT and EBRT+BT patients were equivalent to 78 Gy and 90 Gy in 2 Gy fractions. Over 90% of patients treated with EBRT or EBRT+BT received ADT (median durations of 18 months and 12 months, respectively). Nearly 40% of RP patients received postoperative RT, primarily in the salvage setting. Five- and 10-year DMFS rates were significantly higher with EBRT+BT (91.6% and 81.3%) than with EBRT (79.6% and 65.8%; p < 0.0001) or RP (77.9% and 60.1%; p < 0.0001). Five- and 10-year PCSM rates were significantly lower with EBRT+BT (3.8% and 14.1%) than with EBRT (10.3% and 25.2%; 5- and 10-year hazard ratios of 0.38 and 0.47; p = 0.003) or RP (8.9% and 20.3%; 5- and 10-year hazard ratios of 0.39 and 0.55; p = 0.02). Overall 5- and 10-year OS rates were 85.7% and 64.7% and were similar between cohorts (p > 0.1). Conclusions: Extremely dose-escalated radiotherapy offered improved systemic control and reduced PCSM when compared with either EBRT or RP. Notably, this was achieved despite a significantly shorter median duration of ADT than in the EBRT arm. This is hypothesis generating as it suggests that improved local control via dose-escalation may have systemic control and survival implications even for patients with very high risk disease.

Molecular mechanism and therapeutic implications of selinexor (KPT-330) in liposarcoma

Exportin-1 mediates nuclear export of multiple tumor suppressor and growth regulatory proteins. Aberrant expression of exportin-1 is noted in human malignancies, resulting in cytoplasmic mislocalization of its target proteins. We investigated the efficacy of selinexor against liposarcoma cells both in vitro and in vivo. Exportin-1 was highly expressed in liposarcoma samples and cell lines as determined by immunohistochemistry, western blot, and immunofluorescence assay. Knockdown of endogenous exportin-1 inhibited proliferation of liposarcoma cells. Selinexor also significantly decreased cell proliferation as well as induced cell cycle arrest and apoptosis of liposarcoma cells. The drug also significantly decreased tumor volumes and weights of liposarcoma xenografts. Importantly, selinexor inhibited insulin-like growth factor 1 (IGF1) activation of IGF-1R/AKT pathway through upregulation of insulin-like growth factor binding protein 5 (IGFBP5). Further, overexpression and knockdown experiments showed that IGFBP5 acts as a tumor suppressor and its expression was restored upon selinexor treatment of liposarcoma cells. Selinexor decreased aurora kinase A and B levels in these cells and inhibitors of these kinases suppressed the growth of the liposarcoma cells. Overall, our study showed that selinexor treatment restored tumor suppressive function of IGFBP5 and inhibited aurora kinase A and B in liposarcoma cells supporting the usefulness of selinexor as a potential therapeutic strategy for the treatment of this cancer.

Genomic landscape of liposarcoma

Liposarcoma (LPS) is the most common type of soft tissue sarcoma accounting for 20% of all adult sarcomas. Due to absence of clinically effective treatment options in inoperable situations and resistance to chemotherapeutics, a critical need exists to identify novel therapeutic targets. We analyzed LPS genomic landscape using SNP arrays, whole exome sequencing and targeted exome sequencing to uncover the genomic information for development of specific anti-cancer targets. SNP array analysis indicated known amplified genes (MDM2, CDK4, HMGA2) and important novel genes (UAP1, MIR557, LAMA4, CPM, IGF2, ERBB3, IGF1R). Carboxypeptidase M (CPM), recurrently amplified gene in well-differentiated/de-differentiated LPS was noted as a putative oncogene involved in the EGFR pathway. Notable deletions were found at chromosome 1p (RUNX3, ARID1A), chromosome 11q (ATM, CHEK1) and chromosome 13q14.2 (MIR15A, MIR16-1). Significantly and recurrently mutated genes (false discovery rate < 0.05) included PLEC (27%), MXRA5 (21%), FAT3 (24%), NF1 (20%), MDC1 (10%), TP53 (7%) and CHEK2 (6%). Further, in vitro and in vivo functional studies provided evidence for the tumor suppressor role for Neurofibromin 1 (NF1) gene in different subtypes of LPS. Pathway analysis of recurrent mutations demonstrated signaling through MAPK, JAK-STAT, Wnt, ErbB, axon guidance, apoptosis, DNA damage repair and cell cycle pathways were involved in liposarcomagenesis. Interestingly, we also found mutational and copy number heterogeneity within a primary LPS tumor signifying the importance of multi-region sequencing for cancer-genome guided therapy. In summary, these findings provide insight into the genomic complexity of LPS and highlight potential druggable pathways for targeted therapeutic approach.

CRM1 Inhibition Promotes Cytotoxicity in Ewing Sarcoma Cells by Repressing EWS-FLI1-Dependent IGF-1 Signaling

Ewing sarcoma (EWS) is an aggressive bone malignancy that mainly affects children and young adults. The mechanisms by which EWS (EWSR1) fusion genes drive the disease are not fully understood. CRM1 (XPO1) traffics proteins from the nucleus, including tumor suppressors and growth factors, and is overexpressed in many cancers. A small-molecule inhibitor of CRM1, KPT-330, has shown therapeutic promise, but has yet to be investigated in the context of EWS. In this study, we demonstrate that CRM1 is also highly expressed in EWS. shRNA-mediated or pharmacologic inhibition of CRM1 in EWS cells dramatically decreased cell growth while inducing apoptosis, cell-cycle arrest, and protein expression alterations to several cancer-related factors. Interestingly, silencing of CRM1 markedly reduced EWS-FLI1 fusion protein expression at the posttranscriptional level and upregulated the expression of the well-established EWS-FLI1 target gene, insulin-like growth factor binding protein 3 (IGFBP3), which inhibits IGF-1. Accordingly, KPT-330 treatment attenuated IGF-1-induced activation of the IGF-1R/AKT pathway. Furthermore, knockdown of IGFBP3 increased cell growth and rescued the inhibitory effects on IGF-1 signaling triggered by CRM1 inhibition. Finally, treatment of EWS cells with a combination of KPT-330 and the IGF-1R inhibitor, linsitinib, synergistically decreased cell proliferation both in vitro and in vivo Taken together, these findings provide a strong rationale for investigating the efficacy of combinatorial inhibition of CRM1 and IGF-1R for the treatment of EWS. Cancer Res; 76(9); 2687-97. ©2016 AACR.

Head and neck Epstein-Barr virus mucocutaneous ulcer: Case report and literature review

OBJECTIVES/HYPOTHESIS

To report the clinical presentation, treatment, and management outcomes of patients with Epstein-Barr virus-positive mucocutaneous ulcer (EBVMCU) of the head and neck, which is a newly characterized pathologic entity with aggressive morphology but follows an indolent, self-limiting clinical course.

STUDY DESIGN

Case report and literature review.

METHODS

A case of EBVMCU of the base of tongue is reported and a retrospective review of all cases of EBVMCU of the head and neck at a single academic institution was conducted between January 1, 1986 and April 1, 2015. The MEDLINE database was additionally queried from January 1, 1950 to April 1, 2015 for all reports of EBVMCU of the head and neck, and all pertinent clinical data were extracted.

RESULTS

The clinical presentation, treatment, and response of a patient with EBVMCU of the base of tongue are presented. Interim follow-up of the patient has revealed a complete remission with discontinuation of immunosuppression and rituximab therapy. A review of the literature supports conservative management and reduction of immunosuppression. Overall, 96.6% of patients with follow-up greater than 2 months achieved complete remission with conservative management. The current study is the largest series to report on the clinical presentation and treatment outcomes of EBVMCU of the head and neck.

CONCLUSIONS

EBVMCU tends to follow an indolent and self-limiting clinical course, responding to reduction of immunosuppression and conservative treatment. It is imperative for clinicians to consider EBVMCU in the differential diagnosis of mucocutaneous ulcers of the head and neck to avoid excessive treatment.

LEVEL OF EVIDENCE

Laryngoscope, 126:2500-2504, 2016.

Genomic characterization of sarcomatoid transformation in clear cell renal cell carcinoma

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Background: Sarcomatoid transformation in renal cell carcinoma (ccRCC) is one of the worst prognostic factors and outcome is extremely poor. We evaluate genetic alterations implicated in this process. Methods: Nephrectomy specimens from ccRCC with sarcomatoid transformation had DNA extracted from carcinoma, sarcomatoid, and normal kidney regions. Exome capture/Illumina sequencing was performed in 21 samples. Somatic mutation calling was accomplished by comparing sarcomatoid-normal and carcinoma-normal pairs. Results: Two tumors had evidence of hypermutation and a mutational signature consistent with mismatch repair deficiency. In the remaining tumors, 42.6% of somatic mutations were shared. Sarcomatoid regions had a greater mutation burden (p = 4.0x10-4). A low percentage (57.9%) of tumors had mutations in VHL. Mutations in ccRCC driver genes, including PBRM1, PTEN, SETD2, ARID1A, and BAP1, were common. All mutations in ARID1A and BAP1 were specific to sarcomatoid regions. A high percentage (31.5%) of TP53 mutations were observed, all specific to sarcomatoid regions and occurring with loss of heterozygosity. Lastly, mutations in genes not previously described in ccRCC were observed, most sarcomatoid-specific. These include genes implicated in cell adhesion, polarity, motility, and WNT signaling (FAT1, FAT2, FAT3, PTK7), retinoic acid-regulated cell differentiation (RQCD1, LRIF1), and ubiquitinated protein trafficking and cytokinesis (TSG101). Conclusions: Sarcomatoid transformation in ccRCC results from clonal divergence from a common somatic cell of origin. The sarcomatoid region has significantly greater mutational burden of known cancer driver genes. TP53 mutations occurred at a high frequency and were exclusive to the sarcomatoid region. Hypermutation is a unique characteristic observed in a subset of tumors. Additional cohorts and mechanistic studies are critical to elucidate the role of candidate driver alterations.

Genomic landscape of liposarcoma

Liposarcoma (LPS) is the most common type of soft tissue sarcoma accounting for 20% of all adult sarcomas. Due to absence of clinically effective treatment options in inoperable situations and resistance to chemotherapeutics, a critical need exists to identify novel therapeutic targets. We analyzed LPS genomic landscape using SNP arrays, whole exome sequencing and targeted exome sequencing to uncover the genomic information for development of specific anti-cancer targets. SNP array analysis indicated known amplified genes (MDM2, CDK4, HMGA2) and important novel genes (UAP1, MIR557, LAMA4, CPM, IGF2, ERBB3, IGF1R). Carboxypeptidase M (CPM), recurrently amplified gene in well-differentiated/de-differentiated LPS was noted as a putative oncogene involved in the EGFR pathway. Notable deletions were found at chromosome 1p (RUNX3, ARID1A), chromosome 11q (ATM, CHEK1) and chromosome 13q14.2 (MIR15A, MIR16-1). Significantly and recurrently mutated genes (false discovery rate < 0.05) included PLEC (27%), MXRA5 (21%), FAT3 (24%), NF1 (20%), MDC1 (10%), TP53 (7%) and CHEK2 (6%). Further, in vitro and in vivo functional studies provided evidence for the tumor suppressor role for Neurofibromin 1 (NF1) gene in different subtypes of LPS. Pathway analysis of recurrent mutations demonstrated signaling through MAPK, JAK-STAT, Wnt, ErbB, axon guidance, apoptosis, DNA damage repair and cell cycle pathways were involved in liposarcomagenesis. Interestingly, we also found mutational and copy number heterogeneity within a primary LPS tumor signifying the importance of multi-region sequencing for cancer-genome guided therapy. In summary, these findings provide insight into the genomic complexity of LPS and highlight potential druggable pathways for targeted therapeutic approach.

Abstract A2-20: Integrative study of genomic alterations in liposarcoma

Liposarcoma (LPS) is the most common type of soft tissue sarcoma and accounts for approximately 20% of all adult sarcomas. Due to absence of clinically effective treatment options with a high rate of recurrence and resistance to conventional therapeutics agent, a critical need exists to identify the therapeutic targets for treating this deadly disease. Our study aims to further understanding of LPS pathobiology by constructing a detailed genetic and molecular landscape of LPS through a series of integrated comprehensive genomic and transcriptomic analysis.

We performed SNP CHIP array analysis on 92 LPS cases and 13 LPS cell lines, whole-exome sequencing analysis of 12 LPS-normal paired samples, transcriptome sequencing of 5 cases, targeted whole-exome sequencing of 86 LPS cases and 13 LPS cell lines and intra-tumor heterogeneity analysis in LPS.

We found a variety of genomic aberrations including point mutations, copy number changes, genomic rearrangements, and fusion genes in different subtypes of LPS using next generation sequencing technology. SNP CHIP array analysis revealed significant recurrent copy number amplifications and deletions involving many important well-known cancer genes. One of the important potentially druggable alteration of carboxypeptidase M gene was emerged as new therapeutic strategy in SNP array analysis. The biological and functional characterization of carboxypeptidase M as therapeutic target was done in detail using LPS cell lines and mouse xenograft model system. Using whole exome sequencing, a total 377 potential somatic changes were identified and validated by Sanger sequencing in Discovery cohort. We analyzed the spectrum of mutations detected by whole exome sequencing and found presence of two distinct mutational signatures. Next, a Prevalence Set of additional 86 LPS patients' samples was examined by targeted exome sequencing and numerous non-synonymous mutations identified were validated using Sanger sequencing. Targeted exome sequencing revealed significant recurrent alterations in cell adhesion [60% of cases], DNA damage repair [65% of cases] and kinase [36% of cases] signalling pathways leading to identification of genes that can be potentially targeted using currently available drugs. A class of genes with regulatory roles in axon guidance and cancer cell growth, survival, invasion and angiogenesis were also found to be mutated. RNA sequencing was performed on 5 LPS samples of different histotypes to explore fusion genes. We identified various fusion genes and validated 29 chimeric fusion transcripts using RT-PCR followed by Sanger sequencing across the fusion junctions. We also found the well-known and established classical fusion in LPS cases. Intra-tumor heterogeneity analysis indicates ongoing regional clonal evolution due to the presence of unique mutations in different tumor regions of the same patient tumor sample. Mutations confined to only one of the three tumor regions indicate that interrogation of a single tumor site is not representative of the entire mutational landscape of a patient's tumor. A phylogenetic tree of different tumor regions by clonal ordering shows branching tumor evolution indicating that the majority of genetic events occurred after tumors diverged.

The present investigation provides insights into the underlying mechanism driving liposarcomagenesis and also identifies new therapeutic targets which need to be further investigated. Comprehensive genomic characterization will improve our understanding of the LPS molecular genetics and lay the foundation to refine diagnostic classifications, determine prognosis and develop new therapeutics for treating LPS.

Note: This abstract was not presented at the conference.

Citation Format: Deepika Kanojia, Manoj Garg, Yasunobu Nagata, Dhong Hyun Lee, Hans-Ulrich Klein, Christoph Bartenhagen, Anand M T, Ngan B Doan, Jonathan W Said, Henry Yang, Charles Forscher, Martin Dugas, Seishi Ogawa, H Phillip Koeffler. Integrative study of genomic alterations in liposarcoma. [abstract]. In: Proceedings of the AACR Special Conference on Translation of the Cancer Genome; Feb 7-9, 2015; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(22 Suppl 1):Abstract nr A2-20.

Abstract 122: PARK2 is a negative regulator of Wnt and EGFR pathways in glioma

PARK2 is an E3 ubiquitin ligase whose dysfunction has been associated with the progression of autosomal recessive juvenile Parkinson's disease and human malignancies. However, its role in cancer remains to be explored. In this study, we report that PARK2 is frequently deleted and underexpressed in human glioma, and low PARK2 expression is associated with poor survival in cohorts of both low-grade glioma and glioblastoma multiforme (GBM). Functional studies revealed a tumor-suppressive role of PARK2 in GBM cells. Restoration of PARK2 significantly inhibited glioma cell growth both in vitro and in vivo, while depletion of endogenous PARK2 promoted cell proliferation. cDNA microarray analysis showed that PARK2 expression strongly altered the activity of both the Wnt and EGFR pathways. Immunoblot analysis confirmed that ectopic expression of PARK2 suppressed the intracellular levels of β-catenin, EGFR, as well as their down-stream targets including Cyclin D1, TCF4, c-Myc, p-AKT and p-S6K, etc. Notably, PARK2 physically interacted with both β-catenin and EGFR, and promoted their ubiquitination in an E3-ligase dependent manner. Similar to the ligase-dead PARK2 mutant (C431S), three PARK2 mutants harboring cancer-derived somatic mutations (T173A, T240M and P294S) showed decreased ability to ubiquitinate either β-catenin or EGFR proteins. We further found that PARK2 attenuated the cellular response to both Wnt3a and EGF stimulation, suggesting PARK2 is a negative regulator of both the Wnt and EGFR pathways. Lastly, inspired by these newly identified functions of PARK2, we tested and proved that the combination of small-molecule inhibitors targeting both Wnt-β-catenin and EGFR-AKT pathways synergistically impaired glioma cell viability. In aggregate, our findings uncover novel, cancer-associated functions of PARK2 and provide a potential therapeutic approach to treat glioma.

Citation Format: Liang Xu, De-Chen Lin, Ye Chen, Haiyan Yan, Masaharu Hazawa, Ngan Doan, Jonathan W. Said, Ling-Wen Ding, Li-Zhen Liu, Henry Yang, Shi-zhu Yu, Michael Kahn, Dong Yin, Phillip Koeffler. PARK2 is a negative regulator of Wnt and EGFR pathways in glioma. [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 122. doi:10.1158/1538-7445.AM2015-122

Genomic and Functional Analysis of the E3 Ligase PARK2 in Glioma

PARK2 (PARKIN) is an E3 ubiquitin ligase whose dysfunction has been associated with the progression of Parkinsonism and human malignancies, and its role in cancer remains to be explored. In this study, we report that PARK2 is frequently deleted and underexpressed in human glioma, and low PARK2 expression is associated with poor survival. Restoration of PARK2 significantly inhibited glioma cell growth both in vitro and in vivo, whereas depletion of PARK2 promoted cell proliferation. PARK2 attenuated both Wnt- and EGF-stimulated pathways through downregulating the intracellular level of β-catenin and EGFR. Notably, PARK2 physically interacted with both β-catenin and EGFR. We further found that PARK2 promoted the ubiquitination of these two proteins in an E3 ligase activity-dependent manner. Finally, inspired by these newly identified tumor-suppressive functions of PARK2, we tested and proved that combination of small-molecule inhibitors targeting both Wnt-β-catenin and EGFR-AKT pathways synergistically impaired glioma cell viability. Together, our findings uncover novel cancer-associated functions of PARK2 and provide a potential therapeutic approach to treat glioma.

Randomized clinical trial of brewed green and black tea in men with prostate cancer prior to prostatectomy

BACKGROUND

Preclinical and epidemiologic studies suggest chemopreventive effects of green tea (GT) and black tea (BT) in prostate cancer. In the current study we determined the effect of GT and BT consumption on biomarkers related to prostate cancer development and progression.

METHODS

In this exploratory, open label, phase II trial 113 men diagnosed with prostate cancer were randomized to consume six cups daily of brewed GT, BT or water (control) prior to radical prostatectomy (RP). The primary endpoint was prostate tumor markers of cancer development and progression determined by tissue immunostaining of proliferation (Ki67), apoptosis (Bcl-2, Bax, Tunel), inflammation (nuclear and cytoplasmic nuclear factor kappa B [NFκB]) and oxidation (8-hydroxydeoxy-guanosine [8OHdG]). Secondary endpoints of urinary oxidation, tea polyphenol uptake in prostate tissue, and serum prostate specific antigen (PSA) were evaluated by high performance liquid chromatography and ELISA analysis.

RESULTS

Ninety three patients completed the intervention. There was no significant difference in markers of proliferation, apoptosis and oxidation in RP tissue comparing GT and BT to water control. Nuclear staining of NFκB was significantly decreased in RP tissue of men consuming GT (P = 0.013) but not BT (P = 0.931) compared to water control. Tea polyphenols were detected in prostate tissue from 32 of 34 men consuming GT but not in the other groups. Evidence of a systemic antioxidant effect was observed (reduced urinary 8OHdG) only with GT consumption (P = 0.03). GT, but not BT or water, also led to a small but statistically significant decrease in serum prostate-specific antigen (PSA) levels (P = 0.04).

CONCLUSION

Given the GT-induced changes in NFκB and systemic oxidation, and uptake of GT polyphenols in prostate tissue, future longer-term studies are warranted to further examine the role of GT for prostate cancer prevention and treatment, and possibly for other prostate conditions such as prostatitis.

Establishment and characterization of novel human primary and metastatic anaplastic thyroid cancer cell lines and their genomic evolution over a year as a primagraft

CONTEXT

Anaplastic thyroid cancer (ATC) has no effective treatment, resulting in a high rate of mortality. We established cell lines from a primary ATC and its lymph node metastasis, and investigated the molecular factors and genomic changes associated with tumor growth.

OBJECTIVE

The aim of the study was to understand the molecular and genomic changes of highly aggressive ATC and its clonal evolution to develop rational therapies.

DESIGN

We established unique cell lines from primary (OGK-P) and metastatic (OGK-M) ATC specimen, as well as primagraft from the metastatic ATC, which was serially xeno-transplanted for more than 1 year in NOD scid gamma mice were established. These cell lines and primagraft were used as tools to examine gene expression, copy number changes, and somatic mutations using RNA array, SNP Chip, and whole exome sequencing.

RESULTS

Mice carrying sc (OGK-P and OGK-M) tumors developed splenomegaly and neutrophilia with high expression of cytokines including CSF1, CSF2, CSF3, IL-1β, and IL-6. Levels of HIF-1α and its targeted genes were also elevated in these tumors. The treatment of tumor carrying mice with Bevacizumab effectively decreased tumor growth, macrophage infiltration, and peripheral WBCs. SNP chip analysis showed homozygous deletion of exons 3-22 of the PARD3 gene in the cells. Forced expression of PARD3 decreased cell proliferation, motility, and invasiveness, restores cell-cell contacts and enhanced cell adhesion. Next generation exome sequencing identified the somatic changes present in the primary, metastatic, and primagraft tumors demonstrating evolution of the mutational signature over the year of passage in vivo.

CONCLUSION

To our knowledge, we established the first paired human primary and metastatic ATC cell lines offering unique possibilities for comparative functional investigations in vitro and in vivo. Our exome sequencing also identified novel mutations, as well as clonal evolution in both the metastasis and primagraft.

SETDB1 accelerates tumourigenesis by regulating the WNT signalling pathway

We investigated the oncogenic role of SETDB1, focusing on non-small cell lung cancer (NSCLC), which has high expression of this protein. A total of 387 lung cancer cases were examined by immunohistochemistry; 72% of NSCLC samples were positive for SETDB1 staining, compared to 46% samples of normal bronchial epithelium (106 cases) (p <0.0001). The percentage of positive cells and the intensity of staining increased significantly with increased grade of disease. Forced expression of SETDB1 in NSCLC cell lines enhanced their clonogenic growth in vitro and markedly increased tumour size in a murine xenograft model, while silencing (shRNA) SETDB1 in NSCLC cells slowed their proliferation. SETDB1 positively stimulated activity of the WNT-β-catenin pathway and diminished P53 expression, resulting in enhanced NSCLC growth in vitro and in vivo. Our finding suggests that therapeutic targeting of SETDB1 may benefit patients whose tumours express high levels of SETDB1.

Synergistic effect of JQ1 and rapamycin for treatment of human osteosarcoma

Bromodomain and extra terminal domain (BET) proteins are important epigenetic regulators facilitating the transcription of genes in chromatin areas linked to acetylated histones. JQ1, a BET protein inhibitor, has antiproliferative activity against many cancers, mainly through inhibition of c-MYC and upregulation of p21. In this research, we investigated the use of JQ1 for human osteosarcoma (OS) treatment. JQ1 significantly inhibited the proliferation and survival of OS cells inducing G1 cell cycle arrest, premature senescence, but little effect on apoptosis. Interestingly, c-MYC protein levels in JQ1-treated cells remained unchanged, whereas the upregulation of p21 protein was still observable. Although effective in vitro, JQ1 alone failed to reduce the size of the MNNG/HOS xenografts in immunocompromised mice. To overcome the resistance of OS cells to JQ1 treatment, we combined JQ1 with rapamycin, an mammalian target of rapamycin (mTOR) inhibitor. JQ1 and rapamycin synergistically inhibited the growth and survival of OS cells in vitro and in vivo. We also identified that RUNX2 is a direct target of bromodomain-containing protein 4 (BRD4) inhibition by JQ1 in OS cells. Chromatin immunoprecipitation (ChIP) showed that enrichment of BRD4 protein around RUNX2 transcription start sites diminished with JQ1 treatment in MNNG/HOS cells. Overexpression of RUNX2 protected JQ1-sensitive OS cells from the effect of JQ1, and siRNA-mediated inhibition of RUNX2 sensitized the same cells to JQ1. In conclusion, our findings suggest that JQ1, in combination with rapamycin, is an effective chemotherapeutic option for OS treatment. We also show that inhibition of RUNX2 expression by JQ1 partly explains the antiproliferative activity of JQ1 in OS cells.

Abstract 2819: Efficacy and safety of the Ad-GM·CAIX dendritic cell-based vaccine in treating in vivo metastatic renal cell carcinoma compared to sunitinib monotherapy and simultaneous vaccine-sunitinib combination therapy

Metastatic clear cell renal cell carcinoma (ccRCC) disease is responsible for significant morbidity and represents the main cause of death in patients with advanced ccRCC. We have developed a novel dendritic cell based vaccine targeting human carbonic anhydrase IX (hCAIX; DC-Ad-GM·CAIX) and compared it with the ccRCC standard-of-care drug, sunitinib as a monotherapy and in simultaneous vaccine-sunitinib combination therapy.

Immunocompetent mice (Balb/c) were orthotopically-transplanted with syngeneic RCC-hCAIXpositive (NPR-IX) tumor cells, immunized, and/or treated with sunitinib at low-dose (5mg/kg/d), high-dose (40mg/kg/d) or untreated. At termination, primary tumor size (weight), lung metastatic burden, hCAIX and immune-markers expression levels were compared.

Mono-immunotherapy with DC-Ad-GM·CAIX vaccine suppressed metastatic tumor growth: the total number of metastatic heterotypic foci (i.e., hCAIX positive and negative foci) following vaccination decreased 2.5 fold compared with untreated mice (P&lt;0.05). When counting only the hCAIX positive metastatic tumor cells, the decrease in the metastatic tumor burden compared to untreated mice was even more pronounced (&gt;10 fold). Vaccination alone resulted in reduced primary tumor burden of RCC-hCAIXpositive cells to &lt;25% of the tumor cell population, with the remaining cells lacking hCAIX expression (hCAIXnegative); there was no significant overall primary tumor reduction compared to untreated mice. In contrast, sunitinib, whether given as high-dose monotherapy or in combination with the vaccine, inhibited the primary orthotopic tumors, achieving 35% (P=0.0001) and 51% (P=1.7e-7) tumor reduction, respectively. However, sunitinib monotherapy was less effective in reducing the metastatic tumor burden compared with the vaccine.

In fact, simultaneous administration of vaccine and sunitinib increased the metastatic tumor burden in heterotypic tumors composed also of hCAIXnegative cells.

In conclusion, this preclinical study demonstrates that (i) the DC-Ad-GM·CAIX vaccine effectively controls both primary and metastatic hCAIXpositive tumors and forms the basis for a phase I trial in metastatic ccRCC patients, which has been initiated at UCLA (http://clinicaltrials.gov number NCT01826877), (ii) Antigen editing with loss of hCAIX is an important immune escape mechanism, (iii) This in vivo study raises caution regarding the use of DC-Ad-GM·CAIX vaccine in simultaneous combination therapies with sunitinib.

Co-corresponding Authors: ASB and JR

Citation Format: Edward N. Rampersaud, Jonathan W. Said, Adrian Bot, Frédéric D. Birkhäuser, Nils Kroeger, Gang Zeng, Fairooz F. Kabbinavar, Antoni Ribas, Allan J. Pantuck, Arie S. Belldegrun, Joseph Riss. Efficacy and safety of the Ad-GM·CAIX dendritic cell-based vaccine in treating in vivo metastatic renal cell carcinoma compared to sunitinib monotherapy and simultaneous vaccine-sunitinib combination therapy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2819. doi:10.1158/1538-7445.AM2014-2819

Abstract 5570: Laminin-5 gamma-2 (LAMC2) is highly expressed in anaplastic thyroid carcinoma and is associated with tumor progression, migration and invasion by modulating signaling of EGFR

Context: Anaplastic thyroid carcinoma (ATC) is an aggressive malignancy having no effective treatment. Laminin subunit gamma-2 (LAMC2) is an epithelial basement membrane protein involved in cell migration and tumour invasion and might represent an ideal target for the development of novel therapeutic approaches for ATC.

Objective: Study the role of LAMC2 in ATC tumorigenesis.

Design: LAMC2 expression was evaluated by RT-PCR, western blotting and immunohistochemistry in tumor specimens, adjacent non-cancerous tissues and cell lines. shRNA approach was used to investigate the effect of LAMC2 knockdown on tumorigenesis of ATC.

Results: LAMC2 was highly expressed in ATC samples and cell lines compared to normal thyroid tissues. Silencing LAMC2 by shRNA in ATC cells moderately inhibited cell growth in liquid culture and dramatically decreased growth in soft agar and in xenografts growing in immunodeficient mice. Silencing LAMC2 caused cell cycle arrest and significantly suppressed migration, invasion and wound healing of ATC cells. Rescue experiments by overexpressing LAMC2 in LAMC2 knockdown cells, reversed the inhibitory effects as shown by increased cell proliferation and colony formation. Microarray data demonstrated that LAMC2 shRNA significantly altered expression of genes associated with migration, invasion, proliferation and survival. Immunoprecipitation and co-localization experiments showed that LAMC2 bound to EGFR in ATC cells. Silencing LAMC2 partially blocked EGF-mediated activation of EGFR and its downstream pathway. Interestingly, cetuximab (EGFR blocking antibody) or EGFR siRNA additively enhanced the anti-proliferative activity of the LAMC2 knockdown ATC cells compared to control cells.

Conclusions: To our knowledge, this is the first report investigating the effect of LAMC2 on cell growth, cell cycle, migration, invasion and EGFR signaling in ATC cells, suggesting that LAMC2 may be a potential therapeutic target for treatment of ATC.

Citation Format: Manoj Garg, Deepika Kanojia, Ryoko Okamoto, Vikas Madan, Wenwen Chien, Abhishek Sampath, Ling-Wen Ding, Meng Xuan, Jonathan W Said, Ngan Doan, Li-Zhen Liu, Henry Yang, Sigal Gery, Gleen D Braunstein, H.Phillip Koeffler. Laminin-5 gamma-2 (LAMC2) is highly expressed in anaplastic thyroid carcinoma and is associated with tumor progression, migration and invasion by modulating signaling of EGFR. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5570. doi:10.1158/1538-7445.AM2014-5570

Chromosome 8 alterations and PTEN loss in Gleason grade 3 tumor to predict the presence of unsampled grade 4 tumor: Implications for active surveillance

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Background: A key eligibility criterion in many active surveillance (AS) programs is that the biopsy exhibit only Gleason pattern 3 (G3) for a Gleason score of 6 or less. However, 25 to 35% of biopsy Gleason 6 is upgraded to Gleason 7 or higher in the prostatectomy (RP) specimen. Thus, there is a great need for biomarkers that, when measured on G3 tissue in a Gleason 6 biopsy, can predict the presence of unsampled higher grade tumor in the whole prostate. We evaluated PTEN loss by immunohistochemistry (IHC), and PTEN deletion, chromosome 8q (MYC) gain and 8p (LPL) loss by fluorescence in situ hybridization (FISH) for their ability to predict unsampled G4 tumor. Methods: A tissue microarray (TMA) was constructed of RP tissue from three groups of patients (n=50 per group) whose prostates exhibited only Gleason 3+3, only 3+4, or only 4+3 tumor, matched on age, year of RP, and race. In each patient, multiple cores sampled only from areas of G3 were evaluated for PTEN deletion by FISH, PTEN loss by IHC, and chromosome 8p/8q alterations by FISH. Biomarker results were compared between Gleason 6 versus 7 tumors using conditional logistic regression. Results: Patients underwent RP in 2001 to 2009, had median age 60, and median prostate-specific antigen 5.2; 63% of tumors were organ confined. In univariate analyses 8q gain (odds ratio OR=8.9, p<.0001), 8p loss (OR=6.9, p<.0001), PTEN loss by IHC (OR=5.7, p=.025), but not PTEN deletion by FISH (OR=1.5, p=.477) were significantly more common in G3 cores from Gleason 7 tumors than G3 cores from Gleason 6 tumors. In multivariable analyses, 8q gain (OR=6.2, p=.002) and 8p loss (OR=5.2, p=.0002) remained highly significant. At least one high risk biomarker (8q gain, 8p loss, PTEN loss, or PTEN deletion) was found in 35.7% of Gleason 3+3 versus 77.1% of Gleason 3+4 versus 91.3% of Gleason 4+3 tumors, p<.0001. Adjustment for confounding factors did not change the results. Conclusions: Chromosomal 8q gains (MYC), 8p loss (LPL), and PTEN loss measured in Gleason G3 TMA cores strongly differentiate whether the core comes from Gleason 6 or Gleason 7 tumor. If validated in biopsy Gleason 6 cores to predict prostatectomy Gleason 7 tumor these biomarkers could facilitate safe selection of men for active surveillance.

Validation of the CAIX score as a prognostic biomarker for lymphatic spread and cancer-specific survival

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Background: We recently developed a novel CAIX density scoring system that was found to be a significant prognostic biomarker in a cohort of patients with high-risk clear cell renal cell carcinoma (ccRCC). We sought to validate the association of CAIX score with lymphatic spread and survival in a cohort of patients with ccRCC. Methods: We reviewed the clinical and pathologic records of 418 patients who underwent radical nephrectomy at UCLA between 1985 and 1999. Clinical features included age, gender, race/ethnicity, and ECOG performance status. Pathologic features included TNM stage, nuclear grade, UCLA Integrated Staging System (UISS), and CAIX staining. CAIX score was stratified into low (0–99), intermediate (100–199), and high (200–300). We examined the association between the CAIX score, disease severity, and survival using logistic and Cox regression analyses, respectively. Results: Mean CAIX score was 237.4 (SD 98.3). Approximately 26% of patients with low CAIX scores had lymphatic involvement, compared with 28% of those with intermediate scores, and 8% with high scores, p<0.01. On multivariate analysis, patients with high CAIX scores had a significantly lower risk of lymphatic involvement (OR 0.19, p<0.01). When compared with those with low CAIX scores, patients with high CAIX scores were significantly less likely to recur (HR 0.53, p=0.02) or die (HR 0.41, p<0.01). Patients with intermediate scores were no less likely to recur HR 0.93, p=0.85) or die of their disease (HR 0.69, p=0.34). Lastly, patients with high-risk non-metastatic ccRCC were less likely to recur (HR 0.04, p<0.01). Conclusions: The CAIX score can help identify the majority of patients presenting with lymphatic spread and serves as a statistically significant prognostic biomarker for recurrence-free and disease-free survival after nephrectomy. We recommend that utility CAIX score be quantified for all patients with high-risk disease.

The role of obesity in the incidence of lymphatic spread, disease-free, and overall survival: Data from the ARISER clinical trial

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Background: The role of obesity and the incidence of high-risk clear cell renal cell carcinoma (ccRCC) are poorly understood. We examined the association of obesity with lymphatic spread and survival using data from an international Phase III clinical trial testing the efficacy of adjuvant treatment with cG250 antibody in subjects with non-metastatic (ccRCC) at high risk for recurrence. Methods: We reviewed the clinical and pathologic records of 864 patients across three continents and 14 countries that were enrolled in a prospective, double blind, placebo controlled study of adjuvant cG250 Ab treatment for high-risk ccRCC. Clinical features analyzed included age, gender, race, body mass index (BMI), and performance status. A single pathologist centrally reviewed the specimens for TNM stage and nuclear grade. BMI was stratified into normal (<25 kg/m2), overweight (25.0–29.9 kg/m2), obese (30.0–34.9 kg/m2), and morbidly obese (≥35 kg/m2). We examined the association between BMI, disease severity, and survival using logistic and Cox regression analyses, respectively. Results: Mean BMI was 28.2 kg/m2. The vast majority of our cohort was overweight (43%) and an additional 29% were obese (or morbidly obese). The incidence of lymphatic spread decreased with rising BMI: normal was 11%; overweight was 8%; obese was 5%; and morbidly obese was 2%. Obesity was associated with improved disease-free and overall survival, log rank=0.01 and <0.01, respectively. When compared with those who were normal in weight, subjects who were obese (HR 0.50, p<0.01) and morbidly obese (HR 0.22, p<0.01) had significantly improved overall survival. A trend towards improved disease-free survival was found among subjects who were obese (HR 0.77, p=0.10) and morbidly obese (HR 0.69, p=0.09). Conclusions: While we cannot speak to the association between obesity and ccRCC, our study demonstrates that in a cohort of nephrectomized patients with high-risk disease, obesity is associated with a lower risk of lymphatic spread and improved overall survival.

Laminin-5γ-2 (LAMC2) is highly expressed in anaplastic thyroid carcinoma and is associated with tumor progression, migration, and invasion by modulating signaling of EGFR

CONTEXT

Anaplastic thyroid carcinoma (ATC) is an aggressive malignancy having no effective treatment. Laminin subunit-γ-2 (LAMC2) is an epithelial basement membrane protein involved in cell migration and tumor invasion and might represent an ideal target for the development of novel therapeutic approaches for ATC.

OBJECTIVE

The objective of the investigation was to study the role of LAMC2 in ATC tumorigenesis.

DESIGN

LAMC2 expression was evaluated by RT-PCR, Western blotting, and immunohistochemistry in tumor specimens, adjacent noncancerous tissues, and cell lines. The short hairpin RNA (shRNA) approach was used to investigate the effect of LAMC2 knockdown on the tumorigenesis of ATC.

RESULTS

LAMC2 was highly expressed in ATC samples and cell lines compared with normal thyroid tissues. Silencing LAMC2 by shRNA in ATC cells moderately inhibited cell growth in liquid culture and dramatically decreased growth in soft agar and in xenografts growing in immunodeficient mice. Silencing LAMC2 caused cell cycle arrest and significantly suppressed the migration, invasion, and wound healing of ATC cells. Rescue experiments by overexpressing LAMC2 in LAMC2 knockdown cells reversed the inhibitory effects as shown by increased cell proliferation and colony formation. Microarray data demonstrated that LAMC2 shRNA significantly altered the expression of genes associated with migration, invasion, proliferation, and survival. Immunoprecipitation studies showed that LAMC2 bound to epidermal growth factor receptor (EGFR) in the ATC cells. Silencing LAMC2 partially blocked epidermal growth factor-mediated activation of EGFR and its downstream pathway. Interestingly, cetuximab (an EGFR blocking antibody) or EGFR small interfering RNA additively enhanced the antiproliferative activity of the LAMC2 knockdown ATC cells compared with the control cells.

CONCLUSIONS

To our knowledge, this is the first report investigating the effect of LAMC2 on cell growth, cell cycle, migration, invasion, and EGFR signaling in ATC cells, suggesting that LAMC2 may be a potential therapeutic target for the treatment of ATC.

Association between tumor-associated macrophage infiltration, high grade prostate cancer, and biochemical recurrence after radical prostatectomy

BACKGROUND

Tumor-associated macrophages (TAMs) are a key component of the inflammatory microenvironment. Their role in prostate cancer development and progression remains unclear. We examined whether the amount of TAMs in prostate cancer is: 1) higher than prostatic intraepithelial neoplasia (PIN) and benign tissue 2) associated with poorly differentiated disease, and 3) predictive of biochemical recurrence among surgically treated men.

METHODS

A tissue microarray (TMA) of prostatectomy specimens from 332 patients was stained for CD68, a TAM marker. A separate TMA was used for validation. Associations between mean TAMs in cancer cores and PSA recurrence were determined by Cox proportional hazards models after adjusting for age, preoperative PSA, race, body mass index, pathologic Gleason sum, seminal vesicle invasion, extracapsular extension, and margin status.

RESULTS

Mean TAM number was higher in cancer versus PIN and benign tissue (p<0.0001). Mean TAM number was higher in Gleason grade 4 cores vs. Gleason grade 3 cores (p=0.003). On multivariable analysis, no association was observed between mean TAM number per cancer core and biochemical recurrence in either cohort.

CONCLUSION

Mean TAM number was higher in cancer cores vs. PIN and benign tissue, and higher in high grade prostate cancer supporting the potential role of TAMs in prostate cancer development. However, TAMs were not associated with biochemical recurrence after radical prostatectomy suggesting TAM counts do not provide independent prognostic value among surgically treated men. Further studies are required to elucidate the functional significance of TAMs in the prostate cancer microenvironment.

Off-target effects of c-MET inhibitors on thyroid cancer cells

Aberrantly activated c-MET signaling occurs in several cancers, promoting the development of c-MET inhibitors. In this study, we found that eight of eight thyroid cancer cell lines (including six anaplastic thyroid cell lines) have prominent expression of c-MET protein. Fifty percent of the thyroid cancer cell lines (four of eight) were growth inhibited by two small molecule c-MET inhibitors (tivantinib and crizotinib) associated with apoptosis and G(2)-M cell-cycle arrest. However, crizotinib did not inhibit 50% proliferation of thyroid cancer cells (SW1736 and TL3) at a concentration at which the drug completely inhibited ligand-stimulated c-MET phosphorylation. However, tivantinib was less potent than crizotinib at inhibiting c-MET phosphorylation, but was more potent than crizotinib at decreasing cell growth. Suppressing c-MET protein expression and phosphorylation using siRNA targeting c-MET did not induce cell-cycle arrest and apoptosis. Taken together, tivantinib and crizotinib have off-target(s) activity, contributing to their antitumor activity. In vivo study showed that crizotinib markedly inhibited the growth of thyroid cancer cells (SW1736) in immunodeficient mice. In summary, c-MET inhibitors (tivantinib and crizotinib) suppress the growth of aggressive thyroid cancer cells, and this potential therapeutic benefit results from their non-MET-targeting effects.