Androgen Receptor Activation Induces Senescence in Thyroid Cancer Cells

Thyroid cancer (TC) is the most common endocrine malignancy, with an approximately three-fold higher incidence in women. TCGA data indicate that androgen receptor (AR) RNA is significantly downregulated in PTC. In this study, AR-expressing 8505C (anaplastic TC) (84E7) and K1 (papillary TC) cells experienced an 80% decrease in proliferation over 6 days of exposure to physiological levels of 5α-dihydrotestosterone (DHT). In 84E7, continuous AR activation resulted in G1 growth arrest, accompanied by a flattened, vacuolized cell morphology, with enlargement of the cell and the nuclear area, which is indicative of senescence; this was substantiated by an increase in senescence-associated β-galactosidase activity, total RNA and protein content, and reactive oxygen species. Additionally, the expression of tumor suppressor proteins p16, p21, and p27 was significantly increased. A non-inflammatory senescence-associated secretory profile was induced, significantly decreasing inflammatory cytokines and chemokines such as IL-6, IL-8, TNF, RANTES, and MCP-1; this is consistent with the lower incidence of thyroid inflammation and cancer in men. Migration increased six-fold, which is consistent with the clinical observation of increased lymph node metastasis in men. Proteolytic invasion potential was not significantly altered, which is consistent with unchanged MMP/TIMP expression. Our studies provide evidence that the induction of senescence is a novel function of AR activation in thyroid cancer cells, and may underlie the protective role of AR activation in the decreased incidence of TC in men.

Abstract 1405: Long non-coding RNA LINC01614 augments papillary thyroid cancer cell phenotype

Papillary thyroid cancer (PTC) accounts for the vast majority of thyroid cancer cases and despite high survival rates, disease recurrence and metastasis remain prominent issues. Therefore, there is a need to identify potential molecular markers associated with PTC that aid in early diagnosis, prognosis, and that may serve as therapeutic targets. One area of focus for cancer study is trending towards the epigenome and its functional regulators. The largest subclass of RNA molecules in the human genome consists of long intergenic non-coding RNAs (lincRNAs) with many of their functions yet to be identified. Evidence supports their roles in the regulation of gene expression, as these molecules can act as scaffolds for RNA and protein localization as well as act as molecular “sponges” for binding to and inhibiting action of specific miRNAs. Recently, long non-coding RNA molecules have been demonstrated to play roles in both the development and progression of cancer, deeming them as both attractive and specific biomarkers and/or therapeutic targets for study. Data from our patient sample biobank identified LINC01614 as being significantly upregulated (~12 fold increase) in PTC, when compared to normal, matched thyroid tissue. There was also ~30 fold increase in LINC01614 expression in male PTC, compared to ~5.5 fold increase in female PTC, highlighting a potential sex correlation for study. Thus, we are studying LINC01614 as a potential PTC biomarker. Functional analysis of LINC01614 in vitro found it to be upregulated in various thyroid cancer cell lines, specifically two PTC cell lines: TPC1 (~5 fold; RET/PTC rearrangement; female) and K1 (~2 fold; BRAFV600E; male) when compared to the immortalized “normal” thyroid cell line (Nthy-ori-3-1). To establish a phenotype for LINC01614 expression, we utilized the CRISPRi technique to knockdown expression of this lincRNA in both TPC1 and K1. Knockdown resulted in decreased healing capacity (~20% for both), clonogenicity (~50% and ~34%, respectively), and proliferation (~55% and ~45%, respectively) in both the TPC1 and K1 PTC cell lines. Studies are underway to further assess migration, invasion, and morphology in both cell lines as well as studies to elucidate potential protein interactions and mechanisms of action of LINC01614 in PTC. Studying lincRNAs and their regulatory roles in cancer cell function can aid in the identification of various molecular markers for therapeutic intervention. Elucidation of how these molecules impact PTC development and progression is a promising avenue of exploration.

Citation Format: Danielle Quaranto, Michelle Carnazza, Nicole DeSouza, Sina Dadafarin, Augustine Moscatello, Raj Tiwari, Jan Geliebter. Long non-coding RNA LINC01614 augments papillary thyroid cancer cell phenotype [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1405.

MEG3 Expression Indicates Lymph Node Metastasis and Presence of Cancer-Associated Fibroblasts in Papillary Thyroid Cancer

Papillary thyroid cancer is the most common endocrine malignancy, occurring at an incidence rate of 12.9 per 100,000 in the US adult population. While the overall 10-year survival of PTC nears 95%, the presence of lymph node metastasis (LNM) or capsular invasion indicates the need for extensive neck dissection with possible adjuvant radioactive iodine therapy. While imaging modalities such as ultrasound and CT are currently in use for the detection of suspicious cervical lymph nodes, their sensitivities for tumor-positive nodes are low. Therefore, advancements in preoperative detection of LNM may optimize the surgical and medical management of patients with thyroid cancer. To this end, we analyzed bulk RNA-sequencing datasets to identify candidate markers highly predictive of LNM. We identified MEG3, a long-noncoding RNA previously described as a tumor suppressor when expressed in malignant cells, as highly associated with LNM tissue. Furthermore, the expression of MEG3 was highly predictive of tumor infiltration with cancer-associated fibroblasts, and single-cell RNA-sequencing data revealed the expression of MEG3 was isolated to cancer-associated fibroblasts (CAFs) in the most aggressive form of thyroid cancers. Our findings suggest that MEG3 expression, specifically in CAFs, is highly associated with LNM and may be a driver of aggressive disease.

Multiomics characterization of mouse hepatoblastoma identifies yes-associated protein 1 target genes

BACKGROUND AND AIMS

Hepatoblastoma (HB) is the most common primary liver malignancy in childhood and lacks targeted therapeutic options. We previously engineered, to our knowledge, the first yes-associated protein 1 (YAP1)^S127A -inducible mouse model of HB, demonstrating tumor regression and redifferentiation after YAP1 withdrawal through genome-wide enhancer modulation. Probing accessibility, transcription, and YAP1 binding at regulatory elements in HB tumors may provide more insight into YAP1-driven tumorigenesis and expose exploitable vulnerabilities in HB.

APPROACH AND RESULTS

Using a multiomics approach, we integrated high-throughput transcriptome and chromatin profiling of our murine HB model to identify dynamic activity at candidate cis-regulatory elements (cCREs). We observed that 1301 of 305,596 cCREs exhibit "tumor-modified" (TM) accessibility in HB. We mapped 241 TM enhancers to corresponding genes using accessibility and histone H3K27Ac profiles. Anti-YAP1 cleavage under targets and tagmentation in tumors revealed 66 YAP1-bound TM cCRE/gene pairs, 31 of which decrease expression after YAP1 withdrawal. We validated the YAP1-dependent expression of a putative YAP1 target, Jun dimerization protein 2 (JDP2), in human HB cell lines using YAP1 and LATS1/2 small interfering RNA knockdown. We also confirmed YAP1-induced activity of the Jdp2 TM enhancer in vitro and discovered an analogous human enhancer in silico. Finally, we used transcription factor (TF) footprinting to identify putative YAP1 cofactors and characterize HB-specific TF activity genome wide.

CONCLUSIONS

Our chromatin-profiling techniques define the regulatory frameworks underlying HB and identify YAP1-regulated gene/enhancer pairs. JDP2 is an extensively validated target with YAP1-dependent expression in human HB cell lines and hepatic malignancies.

Abstract 767: Role of COL26A1 in papillary thyroid cancer invasion

Papillary thyroid cancer (PTC) accounts for 70-80% of all thyroid cancer cases and has been increasing in incidence over the last few decades. It is now the 8th most common cancer in women in the United States and the most common cancer in women under 25 years of age. PTC is often curable, as the tumors are most often slow-growing and surgically resectable and lymphatic spread does not worsen the generally favorable prognosis. However, there are aggressive forms of PTC that are not adequately treated by current therapeutic modalities and invasion into surrounding tissue next to the thyroid worsens the prognosis. Utilizing the NYMC biobank of PTC patient samples, meta-analysis of RNASeq data was performed, ranking differentially expressed genes between invasive vs noninvasive and lymph node positive vs lymph node negative samples. These genes were analyzed in conjunction with the GDC’s The Cancer Genome Atlas (TCGA) Thyroid Cancer (THCA) study, in which the Kaplan Meier survival curve identified genes with a significant impact on survival and those that were increased in metastatic tissue samples. Of the top differentially expressed genes that were increased in patients with extrathyroidal extension and lymph node metastasis, COL26A1 significantly inversely associated with survival (p = 0.0086). COL26A1 codes for collagen type XXVI α1 chain with known roles in degradation of the ECM and collagen chain trimerization. In TCGA datasets, COL26A1 expression was significantly correlated with clinical attributes including MACIS score (q = .001), differentiation score (q = 0.025), and tumor stage (q = 0.025). COL26A1 expression was increased 3-fold in papillary thyroid cancer cell line K1 when compared to normal thyroid cancer cells, NThy-ori 3-1. Two CRISPR guides designed to target COL26A1 were introduced into K1 resulting in repression of COL26A1 by 50% in both knockdowns. COL26A1 repression decreased the proliferation (33%), tumorigenicity (86%), invasion (33%), and migration capacity (73%). Furthermore, knockdown of COL26A1 leads to decreased cell-to-cell adhesion in culture. Thus, COL26A1 may have potential use as a prognostic marker and actionable therapeutic target for small molecule inhibitors. Long noncoding RNAs (lncRNAs) have vast implications in different cancer types with roles in gene expression via modulation of coding and noncoding RNAs. lncRNAs are tissue- and stage- specific and stable in serum alluding to their ability to be used in thyroid cancer prognosis and diagnosis. Therefore, we investigated the mRNA-miRNA-lncRNA axis involved in regulation of COL26A1 utilizing Qiagen Ingenuity Pathway Analysis (IPA). We have identified potential pathways linking COL26A1 with PTC, highlighting those involved in proliferation, migration, invasion, and adhesion. Investigation into these molecular interactions and pathways can elucidate the role of COL26A1 and allow for its optimal targeting for treatment of invasive papillary thyroid cancer.

Citation Format: Michelle Carnazza, Danielle Quaranto, Nicole DeSouza, Sina Dadafarin, Augustine Moscatello, Raj K. Tiwari, Jan Geliebter. Role of COL26A1 in papillary thyroid cancer invasion [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 767.

Androgen Activity Is Associated With PD-L1 Downregulation in Thyroid Cancer

Thyroid cancer is the most prevalent endocrine malignancy in the United States with greater than 53,000 new cases in 2020. There is a significant gender disparity in disease incidence as well, with women developing thyroid cancer three times more often than men; however, the underlying cause of this disparity is poorly understood. Using RNA-sequencing, we profiled the immune landscape of papillary thyroid cancer (PTC) and identified a significant inverse correlation between androgen receptor (AR) levels and the immune checkpoint molecule PD-L1. The expression of PD-L1 was then measured in an androgen responsive-thyroid cancer cell line. Dihydrotestosterone (DHT) treatment resulted in significant reduction in surface PD-L1 expression in a time and dose-dependent manner. To determine if androgen-mediated PD-L1 downregulation was AR-dependent, we treated cells with flutamide, a selective AR antagonist, and prior to DHT treatment to pharmacologically inhibit AR-induced signaling. This resulted in a > 90% restoration of cell surface PD-L1 expression, suggesting a potential role for AR activity in PD-L1 regulation. Investigation into the AR binding sites showed AR activation impacts NF-kB signaling by increasing IkBα and by possibly preventing NF-kB translocation into the nucleus, reducing PD-L1 promoter activation. This study provides evidence of sex-hormone mediated regulation of immune checkpoint molecules in vitro with potential ramification for immunotherapies.

Abstract 2254: Coding and noncoding RNA determinants of invasion and migration in papillary thyroid cancer

Papillary thyroid cancer (PTC) is now the 8th most common cancer in women in the United States and has been increasing in incidence over the last few decades. While it is often curable, aggressive forms of PTC that are not adequately treated by current therapeutic modalities invade into surrounding tissue, with a poor prognosis. Thus, the identification of genes involved in PTC migration and invasion is an unmet need. Differentially expressed (PTC vs. matched, normal) coding and noncoding genes from our own biobank were ranked, comparing invasive vs noninvasive, and lymph node positive vs lymph node negative samples. This analysis was supplemented with the interrogation s of The Cancer Genome Atlas (TCGA) PTC gene expression database for survival-associated genes (Kaplan Meier survival curves) utilizing the Xena Browser. This meta-analysis identified genes with a significant impact on survival, that correlated with lymph node metastasis and tumor invasion. SPOCK3, a Ca+2-binding proteoglycan protein with metalloendopeptidase activity, with a role in both extracellular matrix (ECM) degradation and ERK signaling, correlated with both invasiveness and lymph node spread. SLC30A3 (Solute Carrier Family 30 Member 3), involved in the accumulation of zinc in synaptic vesicles and the transport of sugars, bile salts, organic acids, metal ions and amine compounds, also correlated with both invasiveness and lymph node spread. COL26A1, was found to be correlated to tumor invasion and codes for collagen type XXVI α1 chain with known roles in degradation of the ECM and collagen chain trimerization. Long noncoding RNAs (lncRNAs) have vast implications in different cancer types with roles in gene expression via modulation of coding and noncoding RNAs, and are cell, tissue and stage-specific. lncRNAs were identified that correlated with differentiation, invasion and lymph node spread. CRISPR guides were designed and introduced into thyroid cancer cell lines and decreased the invasion and migration capacity of the thyroid cancer cells. This implies their potential use as prognostic markers and actionable therapeutic targets for small molecule inhibitors.

Citation Format: Michelle Carnazza, Sina Dadafarin, Augustine Moscatello, Raj Tiwari, Jan Geliebter. Coding and noncoding RNA determinants of invasion and migration in papillary thyroid cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2254.

Randomized Trial of a Year-Long USMLE Step 1 Preparation Near-Peer Teaching Program

Near-peer teaching (NPT) is a peer-assisted learning method that has been adopted by medical schools as studies have reported benefits to both tutors and tutees. Published studies suggest students may benefit from NPT programs when preparing for the US Medical Licensing Examination (USMLE) Step 1 exam, but they did not use a randomized controlled trial methodology. To determine the impact of a year-long NPT preparation program for the Step 1 examination, we conducted a randomized-controlled trial among second-year medical students at New York Medical College during the 2017-2018 and 2018-2019 academic years. Students who enrolled in the study were invited to complete a post-exam survey, and Step 1 examination scores of intervention and control groups were compared, controlling for preexisting academic differences and demographic traits. While the majority of students reported NPT program participation was a valuable use of their time, we found no significant difference in Step 1 scores between intervention and control groups. Notably, students identifying as female, underrepresented in medicine (UIM) or socioeconomically disadvantaged (SED) enrolled in higher proportions compared to the combined M2 student body of the 2017-2018 and 2018-2019 academic years. Our results may highlight the limitations of NPT programs for board examination preparation and inform the future design of peer-assisted learning programs within medical schools.

Genome-wide detection and analysis of CRISPR-Cas off-targets

The clustered, regularly interspersed, short palindromic repeats (CRISPR) technology is revolutionizing biological studies and holds tremendous promise for treating human diseases. However, a significant limitation of this technology is that modifications can occur on off-target sites lacking perfect complementarity to the single guide RNA (sgRNA) or canonical protospacer-adjacent motif (PAM) sequence. Several in vivo and in vitro genome-wide off-target profiling approaches have been developed to inform on the fidelity of gene editing. Of these, GUIDE-seq has become one of the most widely adopted and reproducible methods. To allow users to easily analyze GUIDE-seq data generated on any sequencing platform, we developed an open-source pipeline, GS-Preprocess, that takes standard base-call output in bcl format and generate all required input data for off-target identification using bioconductor package GUIDEseq for off-target identification. Furthermore, we created a Docker image with GS-Proprocess, GUIDE-seq, and all its R and system dependencies already installed. The bundled pipeline will empower end users to streamline the analysis of GUIDE-seq data and motivate their use of higher throughput sequencing with increased multiplexing for GUIDE-seq experiments.

Abstract 2236: Mechanism of androgen-mediated down-regulation of PD-L1 in thyroid cancer

The incidence of thyroid cancer (ThCa) has more than doubled in the last 20 years and the associated healthcare costs of treating ThCa nears $20 billion in the United States alone. An important disparity exists in the incidence of ThCa, with women developing the disease approximately three times more often than men. A potential explanation of this sex disparity is differences in immune elimination of nascent tumor cells between men and women. Previously, our lab investigated the role androgen receptor (AR) activity may play in thyroid cancer development using an androgen-responsive cell culture model. We further studied the effect of androgen on immune checkpoint molecule expression and identified a significant reduction in PD-L1 transcription and surface expression. In this project, we aim to identify the molecular mechanisms linking AR activity to PD-L1 downregulation. First, we generated two new AR-responsive culture models from a papillary thyroid cancer as well as an anaplastic thyroid cancer cell line for all downstream experiments. These cell lines recapitulated the effect of 5α-dihydrotestosterone (DHT) on PD-L1 expression we previously observed, namely a 70% reduction in PD-L1 expression. We then identified AR binding sites from a collection of AR Chromatin Immunoprecipitation (ChIP)-Sequencing studies from the Cistrome Database. Interestingly, members of the interferon gamma (IFNγ) signaling pathway showed significant AR binding to the promoter or gene body, including negative regulators of IFNγ transcription such as PIAS1. Given the well-known role IFNγ signaling in the regulation of PD-L1, we then performed co-treatment with IFNγ and DHT. Surprisingly, DHT effectively eliminated IFNγ-mediated upregulation of PD-L1 in both cell culture models. We followed up the study by examining STAT1/STAT3 phosphorylation and IRF-1 expression using western blots to identify modulation of the JAK/STAT/IRF axis by AR. Next, we performed CRIPSR-Interference (CRISPRi) in cells co-treated with DHT and IFNγ to determine AR-responsive genes in the IFNγ signaling pathway identified by examination of Cistrome ChIP-Seq that mediated the attenuation of PD-L1 expression in response to DHT. Finally, since AR ChIP studies in the Cistrome database were predominately from prostate cancer cell lines and primary prostate cancer tissue, we performed Cleavage Under Targets and Release Using Nuclease (CUT&RUN) to map AR binding sites genome-wide in our thyroid cancer cell lines. We plan to expand our investigation beyond cultured cells and are optimizing CUT&RUN to examine AR-binding sites in primary human thyroid cancer tissue. By elucidating the regulatory interactions between interferon, AR, and PD-L1 expression, we can potentially better explain the discrepancy between ThCa incidence among the sexes and identify novel immunotherapeutic targets.

Citation Format: Sina Dadafarin, Michelle A. Carnazza, Augustine Moscatello, Raj Tiwari, Jan Geliebter. Mechanism of androgen-mediated down-regulation of PD-L1 in thyroid cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2236.

Dickkopf-3 in aberrant endothelial secretome triggers renal fibroblast activation and endothelial-mesenchymal transition

Background

Our laboratory has previously demonstrated that Sirt1endo-/- mice show endothelial dysfunction and exaggerated renal fibrosis, whereas mice with silenced endothelial transforming growth factor beta (TGF-β) signaling are resistant to fibrogenic signals. Considering the fact that the only difference between these mutant mice is confined to the vascular endothelium, this indicates that secreted substances contribute to these contrasting responses.

Methods

We performed an unbiased proteomic analysis of the secretome of renal microvascular endothelial cells (RMVECs) isolated from these two mutants. We cultured renal fibroblasts and RMVECs and used microfluidic devices for coculturing.

Results

Dickkopf-3 (DKK3), a putative ligand of the Wnt/β-catenin pathway, was present exclusively in the fibrogenic secretome. In cultured fibroblasts, DKK3 potently induced myofibroblast activation. In addition, DKK3 antagonized effects of DKK1, a known inhibitor of the Wnt pathway, in conversion of fibroblasts to myofibroblasts. In RMVECs, DKK3 induced endothelial-mesenchymal transition and impaired their angiogenic competence. The inhibition of endothelial outgrowth, enhanced myofibroblast formation and endothelial-mesenchymal transition were confirmed in coculture. In reporter DKK3-eGFP × Col3.6-GFPcyan mice, DKK3 was marginally expressed under basal conditions. Adriamycin-induced nephropathy resulted in upregulation of DKK3 expression in tubular and, to a lesser degree, endothelial compartments. Sulindac sulfide was found to exhibit superior Wnt pathway-suppressive action and decreased DKK3 signals and the extent of renal fibrosis.

Conclusions

In conclusion, this unbiased proteomic screen of the profibrogenic endothelial secretome revealed DKK3 acting as an agonist of the Wnt pathway, enhancing formation of myofibroblasts and endothelial-mesenchymal transition and impairing angiogenesis. A potent inhibitor of the Wnt pathway, sulindac sulfide, suppressed nephropathy-induced DKK3 expression and renal fibrosis.

Abstract 3570: Investigating coding and non-coding RNA in papillary thyroid cancer

Thyroid cancer is among the most common endocrine malignancies, with papillary thyroid cancer (PTC) accounting for approximately 80% of new thyroid cancer cases in 2017 (ACS). Despite the high sensitivity (95%) of ultrasound-guided fine needle aspiration biopsies (FNAB), approximately 20% of FNA biopsies are indeterminate, which require resection, despite the fact that about 50% are benign. The outcome is that many patients undergo surgical resection of benign disease resulting in avoidable iatrogenic morbidity, and about $700 million in health care costs. Thus, identifying diagnostic/prognostic molecular signatures of PTC would greatly reduce the number of costly, unnecessary resections following indeterminate biopsies. Following consenting of NYEEI patients, surgery, and diagnosis by the pathologist, RNA was prepared from PTC and matched-normal tissue samples, rRNA eliminated and RNA-Seq performed (100bp, paired-end). STARv2.5.2b/ htseq-countv0.6.1 and DESeq2 were used to align raw sequences, and measure transcript abundance. Preliminary bioinformatics analysis was performed with Advaita's iPathway Software. Over 1500 protein-coding transcripts, and 386 lincRNAs achieved 1.5 fold level differential expression (p= 0.05). Gene Ontology enrichment analysis indicated that locomotion, cell motility, signaling, cell differentiation and cell communication were among the most statistically significantly biological processes altered between PTC and matched-normal tissue. Cytokine, signal transducer, ion channel activity, receptor and growth factor activities were among the most statistically significantly molecular functions altered between PTC and matched, normal tissue. Additionally, Pathway Analysis indicated that cell adhesion molecules, cytokine-cytokine receptor, ECM-receptor, cancer, proteoglycans and Jak-Stat signaling were significantly altered. Thyroid differentiation scores (TDS) were calculated for each patients and correlations between differentially expressed lincRNA’s and the TDS were identified. We expect followup experiments modulating the expression of lincRNAs most strongly correlated to the TDS will augment the expression of iodine-handling genes and differentiation in PTC cell lines. We anticipate that the detailed bioinformatics analysis of our coding and noncoding databases in addition to evidence from in vitro studies will yield new diagnostic/prognostic biomarkers, and therapeutic targets.

Citation Format: Sina Dadafarin, Anvita Gupta, Katharine Dermigny, Leyla Cavdar, Brandon Pecchia, Melanie Jones, Timmy O'Connell, JK Rasamny, Nina Suslina, Codrin Iacob, Monica Schwarcz, Ameet Kamat, Cameron Budenz, Craig Berzofsky, Deya Jourdy, Tali Lando, Stimson Schantz, Sarnath Singh, Edward Shin, Augustine Moscatello, Raj Tiwari, Jan Geliebter. Investigating coding and non-coding RNA in papillary thyroid cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3570.

Abstract 3237: Combinatorial immune checkpoint inhibitor therapy in anaplastic thyroid cancer

Anaplastic thyroid cancer(ATC) is a rare but extremely aggressive form of endocrine malignancy that accounts for only 1-2% of total thyroid cancer cases but responsible for 20-30% of annual mortality from thyroid cancer in the USA. Genetic lesion landscape in ATC is not conducive to multiple targeted therapies. BRAF mutation is one of the dominant genetic lesions observed in 30-40% of ATC cases and 98% of them are BRAFV600E positive. Due to the limited therapeutic efficacy of BRAFV600E inhibitor vemurafenib, identification of novel therapeutic candidates would provide a viable alternative. Immunecheckpoint therapies have showed huge promise in recent years but are relatively underexplored in ATC patients. To this end, 4 ATC cell lines 8505C, T238, SW1736 and HTh74; 3 PTC cell lines TPC-1, BCPAP and K1 and 1 FTC cell line CGTH-W-1 were screened for expression of 29 immune-checkpoint molecules by qRT PCR with or without 10μM vemurafenib treatment for 24 hrs. Initial screening revealed a differential expression level of the transcripts among the cells. Vemurafenib treatment further up regulated expression of CD160, HVEM, BTLA, TIM3 and galectin9 in cell lines positive for BRAFV600E mutation (8505C, SW1736, BCPAP) and the ones harboring an additional PIK3CA mutation (T238, K1). This observation was further confirmed by immunocytochemistry. CD160 was not detected in any of the cell lines except for K1, TPC-1 and NTHY at protein level. Flow cytometry confirmed presence of BTLA, HVEM and TIM3 on the surface of these tumor cells which would enable them to engage their cognate ligands on T cells and suppress antitumor immune response. Western blots confirmed upregulation of BTLA, HVEM, TIM3 and galectin 9 in response to vemurafenib in both BRAFV600E positive cell lines and HTh74. Expression of these molecules were also validated by immunohistochemistry in patient samples. In an effort to evaluate the functional activity of these immunecheckpoint molecules, co-culture studies were done. Both HVEM and BTLA showed immunomodulatory capability and were capable of redirecting T cell differentiation towards a suppressive phenotype. Preclinical studies with combination of BRAFV600E or PI3K inhibitor and antagonistic antibodies against these molecules are currently underway. This study has identified two novel immune checkpoint molecules in ATC and might provide viable therapeutic targets.

Citation Format: Sanjukta Chakraborty, Rachana R. Maniyar, Sina Dadafarin, Ghada Ben Rahoma, Sarnath Singh, Augustine Moscatello, Jan Geliebter, Raj K. Tiwari. Combinatorial immune checkpoint inhibitor therapy in anaplastic thyroid cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3237.

Abstract 2469: Coding and non-coding RNA in papillary thyroid cancer - markers for disease progression

Thyroid cancer is among the most common endocrine malignancies, with papillary thyroid cancer (PTC) accounting for approximately 80% of new thyroid cancer cases in 2017 (ACS). Despite the high sensitivity (95%) of ultrasound-guided fine needle aspiration biopsies (FNAB), approximately 20% of FNA biopsies are indeterminate, which require resection, despite the fact that about 50% are benign. The outcome is that many patients undergo surgical resection of benign disease resulting in avoidable iatrogenic morbidity, and about $700 million in health care costs. Thus, identifying diagnostic/prognostic molecular signatures of PTC would greatly reduce the number of costly, unnecessary resections following indeterminate biopsies. Following consenting of NYEEI patients, surgery, and diagnosis by the pathologist, RNA was prepared from PTC and matched-normal tissue samples, rRNA eliminated and RNA-Seq performed (100bp, paired-end). STARv2.5.2b/ htseq-countv0.6.1 and DESeq2 were used to align raw sequences, and measure transcript abundance. Preliminary bioinformatics analysis was performed with Advaita's iPathway Software. Over 1500 protein-coding transcripts, and 386 lincRNAs achieved 1.5 fold level differential expression (p= 0.05). Gene Ontology enrichment analysis indicated that locomotion, cell motility, signaling, cell differentiation and cell communication were among the most statistically significantly biological processes altered between PTC and matched-normal tissue. Cytokine, signal transducer, ion channel activity, receptor and growth factor activities were among the most statistically significantly molecular functions altered between PTC and matched, normal tissue. Additionally, Pathway Analysis indicated that cell adhesion molecules, cytokine-cytokine receptor, ECM-receptor, cancer, proteoglycans and Jak-Stat signaling were significantly altered. Linc01614, linc00475, linc01510, RP11-244M2.1, linc00511, linc01314 and linc00973 were the most overexpressed lncRNAs. Patients who had lymph node metastasis showed differential expression compare to patients with localized disease. These same patients had statistically significantly alterations in the negative regulation of adhesion-dependent cell spreading and cell-matrix adhesion, establishment of cell polarity, and protein kinase C signaling according to Gene Ontology enrichment analysis. In addition to capturing protein coding transcripts, our RNA processing technique has enriched our RNASeq database for novel, noncoding RNAs that are known to play critical roles in cell homeostasis. The biological significance of differentially expressed RNA transcripts is currently being investigated. We anticipate that the detailed bioinformatics analysis of our coding and noncoding databases will yield new diagnostic/prognostic biomarkers, and therapeutic targets.

Citation Format: Sina Dadafarin, Anvita Gupta, Katharine Dermigny, Melanie Jones, Timmy O'Connell, JK Rasamny, Nina Suslina, Iacob Iacob, Monica Schwarcz,, Ameet Kamat, Cameron Budenz, Craig Berzofsky, Deya Jourdy, Tali Lando, Stimson Schantz, Sarnath Singh, Edward Shin, Augustine Moscatello, Raj Tiwari, Jan Geliebter. Coding and non-coding RNA in papillary thyroid cancer - markers for disease progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2469.

The third path of tubulointerstitial fibrosis: aberrant endothelial secretome

The secretome, defined as a portion of proteins secreted by specific cells to the extracellular space, secures a proper microenvironmental niche not only for the donor cells, but also for the neighboring cells, thus maintaining tissue homeostasis. Communication via secretory products exists between endothelial cells and fibroblasts, and this local mechanism maintains the viability and density of each compartment. Endothelial dysfunction, apart from obvious cell-autonomous defects, leads to the aberrant secretome, which predisposes fibroblasts to acquire a myofibroblastic fibrogenic phenotype. In our recent profiling of the secretome of such dysfunctional profibrogenic renal microvascular endothelial cells, we identified unique profibrogenic signatures, among which we detected ligands of Notch and Wnt-β-catenin pathways. Here, we stress the role of reprogramming cues in the immediate microenvironment of (myo)fibroblasts and the contribution of the endothelial secretome to the panoply of instructive signals in the vicinity of fibroblasts. We hope that this brief overview of endothelial-fibroblast communication in health and disease will lead to eventual unbiased proteomic mapping of individual secretomes of glomerular and tubular epithelial cells, pericytes, and podocytes through reductionist approaches to allow for the synthetic creation of a complex network of secretomic signals acting as reprogramming factors on individual cell types in the kidney. Knowledge of profibrogenic and antifibrogenic signatures in the secretome may garner future therapeutic efforts.