Transcriptome analysis identifies TODL as a novel lncRNA associated with proliferation, differentiation, and tumorigenesis in liposarcoma through FOXM1 Running Title: TODL lncRNA as a potential therapeutic target for liposarcoma

Liposarcoma, the most common soft tissue sarcoma, is a group of fat cell mesenchymal tumors with different histological subtypes. The dysregulation of long non-coding RNAs (lncRNAs) has been observed in human cancers including a few studies in sarcoma. However, the global transcriptome analysis and potential role of lncRNAs remain unexplored in liposarcoma. The present investigation uncovers the transcriptomic profile of liposarcoma by RNA sequencing to gain insight into the global transcriptional changes in liposarcoma. Our RNA sequencing analysis has identified that many oncogenic lncRNAs are differentially expressed in different subtypes of liposarcoma including MALAT1, PVT1, SNHG15, LINC00152, and MIR210HG. Importantly, we identified a highly overexpressed, unannotated, and novel lncRNA in dedifferentiated liposarcomas. We have named it TODL, transcript overexpressed in dedifferentiated liposarcoma. TODL lncRNA displayed significantly higher expression in dedifferentiated liposarcoma cell lines and patient samples. Interestingly, functional studies revealed that TODL lncRNA has an oncogenic function in liposarcoma cells by regulating proliferation, cell cycle, apoptosis, differentiation, and tumorigenesis in the murine model. Silencing of TODL lncRNA highlighted the enrichment of several key oncogenic signaling pathways including cell cycle, transcriptional misregulation, FOXM1 network, p53 signaling, PLK1 signaling, FoxO, and signaling Aurora signaling pathways. RNA pull-down assay revealed the binding of TODL lncRNA with FOXM1, an oncogenic transcription factor, and the key regulator of the cell cycle. Silencing of TODL lncRNA also induces adipogenesis in dedifferentiated liposarcomas. Altogether, our finding indicates that TODL could be utilized as a novel, specific diagnostic biomarker, and a pharmacological target for therapeutic development in controlling aggressive and metastatic dedifferentiated liposarcomas.

Novel carfilzomib-based combinations as potential therapeutic strategies for liposarcomas

Proteasome inhibitors, such as bortezomib and carfilzomib, have shown efficacy in anti-cancer therapy in hematological diseases but not in solid cancers. Here, we found that liposarcomas (LPS) are susceptible to proteasome inhibition, and identified drugs that synergize with carfilzomib, such as selinexor, an inhibitor of XPO1-mediated nuclear export. Through quantitative nuclear protein profiling and phospho-kinase arrays, we identified potential mode of actions of this combination, including interference with ribosome biogenesis and inhibition of pro-survival kinase PRAS40. Furthermore, by assessing global protein levels changes, FADS2, a key enzyme regulating fatty acids synthesis, was found down-regulated after proteasome inhibition. Interestingly, SC26196, an inhibitor of FADS2, synergized with carfilzomib. Finally, to identify further combinational options, we performed high-throughput drug screening and uncovered novel drug interactions with carfilzomib. For instance, cyclosporin A, a known immunosuppressive agent, enhanced carfilzomib's efficacy in vitro and in vivo. Altogether, these results demonstrate that carfilzomib and its combinations could be repurposed for LPS clinical management.

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.

Identification of somatic alterations in lipoma using whole exome sequencing

Lipomas are benign fatty tumors with a high prevalence rate, mostly found in adults but have a good prognosis. Until now, reason for lipoma occurrence not been identified. We performed whole exome sequencing to define the mutational spectrum in ten lipoma patients along with their matching control samples. We presented genomic insight into the development of lipomas, the most common benign tumor of soft tissue. Our analysis identified 412 somatic variants including missense mutations, splice site variants, frameshift indels, and stop gain/lost. Copy number variation analysis highlighted minor aberrations in patients. Kinase genes and transcriptions factors were among the validated mutated genes critical for cell proliferation and survival. Pathway analysis revealed enrichment of calcium, Wnt and phospholipase D signaling in patients. In conclusion, whole exome sequencing in lipomas identified mutations in genes with a possible role in development and progression of lipomas.

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.

Targeting super-enhancer-associated oncogenes in oesophageal squamous cell carcinoma

OBJECTIVES

Oesophageal squamous cell carcinoma (OSCC) is an aggressive malignancy and the major histological subtype of oesophageal cancer. Although recent large-scale genomic analysis has improved the description of the genetic abnormalities of OSCC, few targetable genomic lesions have been identified, and no molecular therapy is available. This study aims to identify druggable candidates in this tumour.

DESIGN

High-throughput small-molecule inhibitor screening was performed to identify potent anti-OSCC compounds. Whole-transcriptome sequencing (RNA-Seq) and chromatin immunoprecipitation sequencing (ChIP-Seq) were conducted to decipher the mechanisms of action of CDK7 inhibition in OSCC. A variety of in vitro and in vivo cellular assays were performed to determine the effects of candidate genes on OSCC malignant phenotypes.

RESULTS

The unbiased high-throughput small-molecule inhibitor screening led us to discover a highly potent anti-OSCC compound, THZ1, a specific CDK7 inhibitor. RNA-Seq revealed that low-dose THZ1 treatment caused selective inhibition of a number of oncogenic transcripts. Notably, further characterisation of the genomic features of these THZ1-sensitive transcripts demonstrated that they were frequently associated with super-enhancer (SE). Moreover, SE analysis alone uncovered many OSCC lineage-specific master regulators. Finally, integrative analysis of both THZ1-sensitive and SE-associated transcripts identified a number of novel OSCC oncogenes, including PAK4, RUNX1, DNAJB1, SREBF2 and YAP1, with PAK4 being a potential druggable kinase.

CONCLUSIONS

Our integrative approaches led to a catalogue of SE-associated master regulators and oncogenic transcripts, which may significantly promote both the understanding of OSCC biology and the development of more innovative therapies.

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

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.

Comprehensive mutational analysis of primary and relapse acute promyelocytic leukemia

Acute promyelocytic leukemia (APL) is a subtype of myeloid leukemia characterized by differentiation block at the promyelocyte stage. Besides the presence of chromosomal rearrangement t(15;17), leading to the formation of PML-RARA (promyelocytic leukemia-retinoic acid receptor alpha) fusion, other genetic alterations have also been implicated in APL. Here, we performed comprehensive mutational analysis of primary and relapse APL to identify somatic alterations, which cooperate with PML-RARA in the pathogenesis of APL. We explored the mutational landscape using whole-exome (n=12) and subsequent targeted sequencing of 398 genes in 153 primary and 69 relapse APL. Both primary and relapse APL harbored an average of eight non-silent somatic mutations per exome. We observed recurrent alterations of FLT3, WT1, NRAS and KRAS in the newly diagnosed APL, whereas mutations in other genes commonly mutated in myeloid leukemia were rarely detected. The molecular signature of APL relapse was characterized by emergence of frequent mutations in PML and RARA genes. Our sequencing data also demonstrates incidence of loss-of-function mutations in previously unidentified genes, ARID1B and ARID1A, both of which encode for key components of the SWI/SNF complex. We show that knockdown of ARID1B in APL cell line, NB4, results in large-scale activation of gene expression and reduced in vitro differentiation potential.

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.

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.

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

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.

Sperm associated antigen 9 plays an important role in bladder transitional cell carcinoma

Background

Majority of bladder cancer deaths are caused due to transitional cell carcinoma (TCC) which is the most prevalent and chemoresistant malignancy of urinary bladder. Therefore, we analyzed the role of Sperm associated antigen 9 (SPAG9) in bladder TCC.

Methodology and Findings

We examined SPAG9 expression and humoral response in 125 bladder TCC patients. Four bladder cancer cell lines were assessed for SPAG9 expression. In addition, we investigated the effect of SPAG9 ablation on cellular proliferation, cell cycle, migration and invasion in UM-UC-3 bladder cancer cells by employing gene silencing approach. Our SPAG9 gene and protein expression analysis revealed SPAG9 expression in 81% of bladder TCC tissue specimens. High SPAG9 expression (>60% SPAG9 positive cells) was found to be significantly associated with superficial non-muscle invasive stage (P = 0.042) and low grade tumors (P = 0.002) suggesting SPAG9 putative role in early spread and tumorigenesis. Humoral response against SPAG9 was observed in 95% of patients found positive for SPAG9 expression. All four bladder cancer cell lines revealed SPAG9 expression. In addition, SPAG9 gene silencing in UM-UC-3 cells resulted in induction of G₀–G₁ arrest characterized by up-regulation of p16 and p21 and consequent down-regulation of cyclin E, cyclin D and cyclin B, CDK4 and CDK1. Further, SPAG9 gene silencing also resulted in reduction in cellular growth, and migration and invasion ability of cancer cells in vitro.

Conclusions

Collectively, our data in clinical specimens indicated that SPAG9 is potential biomarker and therapeutic target for bladder TCC.

Sperm-associated antigen 9 is a novel biomarker for colorectal cancer and is involved in tumor growth and tumorigenicity

Colorectal cancer (CRC) is the second most common tumor in developed countries. The present study was undertaken to determine the expression of the sperm-associated antigen 9 gene (SPAG9) as a possible biomarker in CRC, to investigate its correlation with humoral immune response and different stages and grades in CRC patients, and to explore its possible role in colon tumorigenesis in vitro and in an in vivo mouse model. SPAG9 expression was determined by RT-PCR, in situ RNA hybridization, and immunohistochemistry. Humoral response against SPAG9 was detected by enzyme-linked immunosorbent assay and Western blotting. SPAG9 gene silencing was performed using plasmid-based small interfering RNA to study various malignant properties of colon cancer cells in vitro and in vivo. The majority of CRC patients showed SPAG9 expression and generated humoral response. There was a close relationship between SPAG9 protein expression and humoral immune response in the majority of early-stage CRC patients, indicating that anti-SPAG9 antibodies could be a novel serum biomarker for early diagnosis. The down-regulation of SPAG9 (mediated by small interfering RNA) inhibited malignant properties in in vitro and significantly suppressed tumor growth in vivo. These findings collectively suggest that SPAG9 may have a role in tumor development and early spread and thus could serve as a novel target for early detection and for cancer immunotherapy.

Germ cell-specific heat shock protein 70-2 is expressed in cervical carcinoma and is involved in the growth, migration, and invasion of cervical cells

BACKGROUND

Cervical cancer is a major cause of death among women worldwide, and the most cases are reported in the least developed countries. Recently, a study on DNA microarray gene expression analysis demonstrated the overexpression of heat shock protein 70-2 (HSP70-2) in cervical carcinoma cells (HeLa). The objective of the current study was to evaluate the association between HSP70-2 expression in cervical carcinogenesis and its potential role in various malignant properties that result in disease progression.

METHODS

HSP70-2 expression was examined in various cervical cancer cell lines with different origins and in clinical cervical cancer specimens by reverse transcriptase-polymerase chain reaction (RT-PCR), flow cytometry, and immunohistochemistry (IHC) analyses. A plasmid-based, short-hairpin RNA approach was used specifically to knock down the expression of HSP70-2 in cervical tumor cells in vitro and in vivo to examine the role of HSP70-2 on various malignant properties.

RESULTS

RT-PCR and IHC analyses revealed HSP70-2 expression in 86% of cervical cancer specimens. Furthermore, knockdown of HSP70-2 expression significantly reduced cellular growth, colony formation, migration, and invasion in vitro and reduced tumor growth in vivo. A significant association of HSP70-2 gene and protein expression was observed among the various tumor stages (P=.046) and different grades (P=.006), suggesting that HSP70-2 expression may be an indicator of disease progression.

CONCLUSIONS

The current findings suggested that HSP70-2 may play an important role in disease progression in cervical carcinogenesis. Patients who had early stage disease and low-grade tumors had HSP70-2 expression, supporting its potential role in early detection and aggressive treatment modalities for cervical cancer management.

Sperm associated antigen 9 expression and humoral response in chronic myeloid leukemia

Early diagnosis and cure for patients with chronic myeloid leukemia (CML) exhibit significant clinical challenges because of the disease progression from chronic phase (CP) into a rapidly fatal blast crisis. Our earlier studies suggested an association of sperm associated antigen 9 (SPAG9) with various human malignancies. The present investigation revealed that SPAG9 mRNA and protein are expressed in CML patients (88%), in K562 and KCL-22 cells. Further, SPAG9 protein expression was also detected on cell surface suggesting that this molecule may be a suitable target for immunotherapy. Interestingly, 90% CML-CP patients showed humoral response against SPAG9, suggesting its important role in early diagnostic of CML-CP. Further investigation is warranted in establishing the potential of SPAG9 as a biomarker and immunotherapeutic target for early treatment of CML-CP patients.

Small interfering RNA-mediated down-regulation of SPAG9 inhibits cervical tumor growth

BACKGROUND

The expression of the SPAG9 is associated with various human malignancies. Earlier work revealed a significant association of SPAG9 expression with the early spread of cervical cancer, making it an attractive therapeutic target. Here, the authors investigated the role of SPAG9 in carcinogenesis of squamous cell carcinoma (SCC) of the cervix. Furthermore, they sought to determine whether ablation of SPAG9 expression reduces the tumor growth of cervical SCC in vivo.

METHODS

A plasmid-based small interfering RNA approach was used to specifically knock down the expression of SPAG9 in SiHa cells derived from SCC of the cervix in vitro and in vivo. Reverse transcriptase polymerase chain reaction, immunofluorescence staining, flow cytometry, cellular growth, colony formation, migration, invasion, and wound healing assays were studied to characterize SPAG9 in vitro. Furthermore, a cervical cancer xenograft model in nude mice was established to investigate whether knockdown of SPAG9 reduces the tumor growth of cervical SCC in vivo.

RESULTS

The results demonstrated that silencing the SPAG9 by small interfering RNA resulted in inhibition of cell growth, colony formation, migration, and invasion. The authors showed for the first time that the knockdown of SPAG9 expression by small interfering RNA significantly suppressed the tumor growth of cervical SCC in vivo.

CONCLUSIONS

These results suggest that SPAG9 expression may play a pivotal role in tumor growth and could contribute to the early spread of cervical cancer. Small interfering RNA-mediated down-regulation of SPAG9 represents a promising therapeutic approach for the treatment of cervical cancer.

Sperm-associated antigen 9: a novel diagnostic marker for thyroid cancer

CONTEXT

Cancer-testis antigens are the unique class of testis proteins expressed in tumor but not healthy tissue except testis and might represent ideal targets for the development of novel diagnostics and therapeutic methods in thyroid cancer, which is the most common malignancy of the endocrine system.

OBJECTIVE

Our objective was to investigate the clinical relevance of cancer-testis antigen sperm-associated antigen 9 (SPAG9) as early diagnostic and therapeutic target in thyroid cancer.

DESIGN, SETTING, AND SUBJECTS

SPAG9 gene and protein expression was determined in thyroid cancer cell lines in 138 thyroid tumor specimens, 60 adjacent noncancerous tissues (ANCT), 22 multinodular goiters (nonneoplastic hyperplasia), and 20 follicular adenoma tissue samples by RT-PCR, in situ RNA hybridization, and immunohistochemistry. Gene silencing approach was used to examine the effects of suppression of SPAG9 protein on cellular growth and colony formation. Humoral immune response against SPAG9 in thyroid cancer patients was analyzed using ELISA.

RESULTS

SPAG9 mRNA and protein expression was detected in 78% of the thyroid cancer patients but not multiple goiters and follicular adenoma disease patients. It is interesting to note that majority of early-stage (T1) thyroid cancer patients exhibited higher antibody response against SPAG9. Small interfering RNA-mediated knockdown of SPAG9 expression in thyroid cancer cell significantly reduced cellular growth and colony formation.

CONCLUSIONS

SPAG9 expression may play a role in cellular growth and thyroid carcinogenesis. These findings support a potential role for SPAG9 as diagnostic biomarker as well as a possible therapeutic target in thyroid cancer treatment.

Sperm-associated antigen 9 is a biomarker for early cervical carcinoma

BACKGROUND

Cervical cancer is the second most common malignancy in women, with nearly half a million new cases diagnosed each year worldwide. The authors' recent studies have suggested an association of the cancer testis antigen sperm-associated antigen 9 (SPAG9) in ovarian carcinomas. The aim of the current study was to evaluate the clinical utility of SPAG9 expression and humoral immune response in cervical carcinomas.

METHODS

SPAG9 mRNA expression was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR) and in situ RNA hybridization. In addition, the authors investigated SPAG9 protein expression by immunohistochemistry and analyzed its association with various stages and grades of cervical cancer patients. They also tested the humoral immune response against SPAG9 in cervical cancer patients.

RESULTS

RT-PCR, in situ RNA hybridization, and immunohistochemical analyses revealed that SPAG9 expression was significantly associated with tumor grades in 82% of early stage cervical cancer specimens. SPAG9 antibodies were detected in approximately 80% of cervical cancer patients, but not in healthy controls. Statistical analysis revealed that a significant proportion of early stage cancer patients with a high SPAG9 immunoreactivity score (IRS) exhibited significantly higher antibody response against SPAG9 compared with moderate SPAG9 IRSs, suggesting a close relation between SPAG9 protein expression and humoral immune response.

CONCLUSIONS

The current study findings revealed that in early stage cervical cancer, a substantial number of patients exhibited SPAG9 expression and generated SPAG9 antibodies, supporting its potential role in early detection and diagnosis in cervical cancer management. Furthermore, these findings provide leads for future development of noninvasive serologic biomarkers for the early detection, diagnosis, and treatment of cervical cancer.

Sperm-associated antigen 9, a novel biomarker for early detection of breast cancer

To date, there have been no tumor biomarkers validated and incorporated into oncologic practice for the early diagnosis of breast cancer. Recently, we showed that sperm-associated antigen 9 (SPAG9), a member of cancer testis (CT) antigen family, is associated with ovarian carcinomas. In the present study, we investigated SPAG9 expression and humoral immune response in breast cancer. We further evaluated the diagnostic potential of autoantibodies to SPAG9 protein in various stages, grades, and histotypes of breast cancer. We analyzed the association of SPAG9 immunoreactivity score (IRS) with predicted risk of breast cancer recurrence over 10 years. Our reverse transcription-PCR and immunohistochemical analyses revealed SPAG9 expression in 88% breast cancer specimens independent of tumor stages and grades. Further, the humoral immune response against SPAG9 was detected in 80% breast cancer patients with SPAG9-expressing tumors. The linear regression modeling predicted a direct relationship between presence of lymphovascular invasion and high SPAG9 IRS, whereas the univariate and multivariate logistic regression models predicted a strong association of SPAG9 IRS with tumor grade. Further, our data indicated a significant higher trend of SPAG9 IRS with the predicted high risk of breast cancer recurrence. The present investigation reports for the first time SPAG9 expression and humoral immune response in early stages and low-grade breast cancer. Although our data indicated that autoantibodies against SPAG9 represent a promising approach for the development of biomarker, further large-scale validation studies are required to establish its potential use in early diagnosis and monitoring of breast cancer recurrence.

Sperm-associated antigen 9 is associated with tumor growth, migration, and invasion in renal cell carcinoma

Renal cell carcinoma (RCC) represents one of the most resistant tumors to radiation and chemotherapy. Current therapies for RCC patients are inefficient due to the lack of diagnostic and therapeutic markers. Our recent studies have suggested an association of sperm-associated antigen 9 (SPAG9) with ovarian carcinomas. In the present study, we investigated the clinical relevance of SPAG9 in RCC patients. RT-PCR analysis showed expression of SPAG9 transcript in RCC tissues and RCC cell lines. In situ RNA hybridization and immunohistochemistry analyses confirmed the expression of SPAG9 in 88% of cancer patients, suggesting that SPAG9 participates in renal cancer. In addition, immunoblotting and ELISA analyses revealed a humoral immune response against SPAG9 in the sera of RCC patients but not in healthy individuals. Consistent with the clinical findings, knockdown of SPAG9 expression in RCC cells with specific siRNA significantly reduced cell growth and colony formation. Using in vitro wound healing and Matrigel invasion assays, we found that cell migration and invasive ability were also significantly inhibited. Furthermore, in vivo xenograft studies in nude mice revealed that administration of a SPAG9 siRNA plasmid significantly inhibited tumor growth. In conclusion, SPAG9 expression is associated with clinicopathologic features of tumors, suggesting that SPAG9 could contribute to the early spread of cancer. These results indicate that SPAG9 may have a role in tumor development and metastasis and thus could serve as a novel target for early detection and treatment of RCC.

Sperm-associated antigen 9, a novel cancer testis antigen, is a potential target for immunotherapy in epithelial ovarian cancer

PURPOSE

Cancer testis antigens are a group of tumor antigens with gene expression restricted to male germ cells in the testis and in various cancerous tissues. Recently, we reported a novel testis-specific sperm-associated antigen 9 (SPAG9) gene, a new member of the c-Jun NH(2)-terminal kinase-interacting protein family, having functional role in sperm-egg fusion and mitogen-activated protein kinase signaling pathway. National Center for Biotechnology Information Blast searches revealed SPAG9 nucleotide sequence similarities with expressed sequence tags of various cancerous tissues. In an effort to examine the clinical utility of SPAG9, we investigated the SPAG9 mRNA and protein expression in epithelial ovarian cancer (EOC). Humoral immune response to SPAG9 was also evaluated in EOC patients.

EXPERIMENTAL DESIGN

We determined the expression profile of SPAG9 transcript by reverse transcription-PCR and RNA in situ hybridization and SPAG9 protein expression by immunohistochemistry in EOC specimens and human ovarian cancer cell lines. Using ELISA and Western blotting, we analyzed specific antibodies for SPAG9 in sera from patients with EOC.

RESULTS

SPAG9 mRNA and protein expression was detected in 90% of EOC tissues and in all three human ovarian cancer cell lines. Specific SPAG9 antibodies were detected in 67% of EOC patients and not in sera from healthy individuals.

CONCLUSIONS

Our findings indicate that SPAG9 is highly expressed in EOC and immunogenic in patients. Humoral immune response against SPAG9 in early stages of EOC suggests its important role in early diagnostics. These results collectively suggest that SPAG9, a novel member of cancer testis antigen family, could be a potential target for the development of diagnostic and therapeutic methods in EOC.