Adrenocortical tumors have a distinct, long, non-coding RNA expression profile and LINC00271 is downregulated in malignancy

BACKGROUND

Adrenocortical carcinoma is an aggressive malignancy with a low but variable overall survival rate. The role of in adrenocortical carcinoma is poorly understood. Thus, in this study we performed long noncoding RNA expression profiling in adrenocortical carcinomas, adrenocortical adenomas, and normal adrenal cortex.

METHODS

Long noncoding RNA expression profile using Human LncRNA/mRNA Expression Microarray V3.0 (Arraystar, Inc, Rockville, MD) was analyzed in samples from 11 adrenocortical adenomas, 9 adrenocortical carcinomas, and 5 normal adrenal cortex. Differentially expressed long noncoding RNAs were validated using TaqMan, real-time quantitative polymerase chain reaction with additional samples. The dataset from the adrenocortical carcinoma Cancer Genome Atlas Programproject was used to evaluate the prognostic utility of long noncoding RNAs.

RESULTS

Unsupervised hierarchical clustering showed distinct clustering of adrenocortical carcinoma samples compared with normal adrenal cortex and adrenocortical adenoma samples by long noncoding RNA expression profiles. A total of 874 long noncoding RNAs were differentially expressed between adrenocortical carcinoma and normal adrenal cortex. LINC00271 expression level was associated with prognosis, patients with low LINC00271 expression survived a shorter time than patients with high LINC00271 expression. Low LINC00271 expression was positively associated with WNT signaling, cell cycle, and chromosome segregation pathways.

CONCLUSION

Adrenocortical carcinoma has a distinct long noncoding RNA expression profile. LINC00271 is downregulated in adrenocortical carcinoma and appears to be involved in biologic pathways commonly dysregulated in adrenocortical carcinoma.

Serum RARRES2 Is a Prognostic Marker in Patients With Adrenocortical Carcinoma

CONTEXT

Retinoic acid receptor responder protein 2 (RARRES2) is a small secreted protein involved in multiple cancers, including adrenocortical carcinoma (ACC). However, discordant tumor and serum RARRES2 levels have been reported in various cancers. The etiology of this discordance is unknown and has not been studied in pair-matched tumor and serum samples.

OBJECTIVE

To determine tissue and serum RARRES2 levels in patients with adrenocortical neoplasm and to elucidate the prognostic implications of RARRES2 levels.

DESIGN, SETTINGS, AND PATIENTS

Tissue and serum RARRES2 levels were analyzed. A pair-matched analysis was performed to examine tissue and serum RARRES2 from 51 patients with benign adrenocortical tumors and 18 patients with ACC. Overall survival was analyzed based on RARRES2 expression. A mouse xenograft model was used to determine the source of serum RARRES2.

RESULTS

Patients with ACC had decreased tumor RARRES2 gene expression (P < .0001) and increased serum RARRES2 levels (P < .005) as compared with patients with benign adrenocortical tumors. Higher serum RARRES2 levels were associated with improved overall survival (P = .0227). A mouse xenograft model demonstrated that higher tissue RARRES2 expression was associated with higher RARRES2 secretion in the serum and that there was an intrinsic mechanism in maintaining serum RARRES2 homeostasis.

CONCLUSIONS

Serum and tissue RARRES2 expression levels are paradoxical in patients with ACC. The elevated RARRES2 in patient serum is unlikely to be secreted from tumor cells. Serum RARRES2 may be used as a novel prognostic marker for ACC.

Abstract 3578: Novel insights into the cellular function and gene regulation of a master mutator, APOBEC3B

Unequivocally, cumulative mutations are required for the development of cancer and many sources of mutagenic activity contribute to tumorigenesis. Recent evidence has implicated that a member of cytidine deaminase family, APOBEC3B (Apolipoprotein B mRNA editing enzyme, catalytic polypeptide-like 3B or A3B) is enriched in the genomes of many human cancers such as cervical, bladder, lung, head and neck and breast cancers (Burns et al., Nature, 2013). APOBEC3B deaminate cytosines in the host genome to generate C-T mutations. Here we report for the first time that APOBEC3B is overexpressed with adrenocortical carcinoma (ACC), a very aggressive and lethal malignancy. We found that APOBEC3B is significantly overexpressed in primary and metastatic ACC as compared to normal adrenal and cortical adenomas by qPCR, immunofluorescence. We observed that γH2AX, a marker of DNA double-strand breaks co-localizes with the expression of APOBEC3B in patients with primary and metastatic ACC. Also ACC tumor samples with high APOBEC3B expression had high chromosomal gain/loss particularly in chromosome 4 and 8 compared to tumor samples with low APOBEC3B expression. To identify the cellular function of APOBEC3B, we performed transient knock-down studies in three ACC cell lines and found that it reduces cellular proliferation and induces cell cycle arrest. Furthermore, we observed that knockdown of APOBEC3B inhibits MAPK signaling by downregulating phospho ERK1/2 levels. Interestingly, we found that tumors with high APOBEC3B expression levels had twice as many TP53 inactivating mutations as compared to tumors with low levels of APOBEC3B. In order to understand the regulation of APOBEC3B expression, we analyzed the methylation status, copy number variation and potential targeting miRNAs of APOBEC3B from genome wide array platform but found no associations in human ACC samples. Therefore, we did a functional, knockdown screen of 90 cancer-associated transcription factors and found that GATA3 showed positive regulation of APOBEC3B. Our data provide novel insights into the function and regulation of APOBEC3B expression beyond its known mutagenic ability.

Citation Format: Sudheer Kumar Gara, Yi Liu-Chittenden, Shweta Kotian, Dhaval Patel, Electron Kebebew. Novel insights into the cellular function and gene regulation of a master mutator, APOBEC3B. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3578.

Abstract 3664: RARRES2 functions as a direct tumor suppressor by promoting beta-catenin phosphorylation and degradation independent of CMKLR1 and CMKLR1-mediated antitumor immune response in adrenocortical carcinoma

Tumor suppressors and the immune system are critical players in tumor suppression. However, little is known about whether a tumor suppressor can function through both immune-dependent and immune-independent mechanisms. RARRES2 is a small secreted protein that is down-regulated in multiple human cancer types such as adrenocortical carcinoma (ACC), hepatocellular carcinoma (HCC) and melanoma. It has been shown that RARRES2 can play an indirect tumor-suppressive role by acting as a chemoattractant to recruit anti-cancer immune cells expressing its receptor CMKLR1 to sites of tumor. In this study, we show that epigenetic CpG hypermethylation of RARRES2 in vivo and in vitro in ACC causes RARRES2 down-regulation. We also found that RARRES2 can function as a direct tumor suppressor and that its tumor suppressive effect does not depend on the recruitment of CMKLR1-expressing immune cells. We show that although exogenous treatment of cultured cells with recombinant human RARRES2 protein did not show any tumor-suppressive effect, transient overexpression of RARRES2 significantly inhibited cellular invasion. Stable overexpression of RARRES2 in ACC cell line NCI-H295R led to significantly reduced cell proliferation, cell invasion, and tumorigenecity in a RARRES2 dose-dependent manner. Using xenografts of stable NCI-H295R cell lines in two immunodeficient mouse models (athymic nude mice and NSG mice), we found that in the absence of functional immune cells, stable RARRES2 overexpression can still significantly suppress tumor growth in vivo. RARRES2 overexpression promoted beta-catenin phosphorylation and degradation, reduced the phosphorylation of p38 MAP kinase and inhibited the secretion of matrix metalloprotease protein 10 (MMP10) from cancer cells in a RARRES2 dose-dependent manner. Taken into account that CMKLR1 expression is barely detectable in all the cell lines tested, our results present the first evidence that RARRES2 can function as a direct tumor suppressor independent of CMKLR1 and CMKLR1-mediated anti-tumor immune response.

Citation Format: Yi Liu-Chittenden, Kelli Gaskins, Sophie Wang, Electron Kebebew. RARRES2 functions as a direct tumor suppressor by promoting beta-catenin phosphorylation and degradation independent of CMKLR1 and CMKLR1-mediated antitumor immune response in adrenocortical carcinoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3664.

Integrated genome-wide analysis of genomic changes and gene regulation in human adrenocortical tissue samples

To gain insight into the pathogenesis of adrenocortical carcinoma (ACC) and whether there is progression from normal-to-adenoma-to-carcinoma, we performed genome-wide gene expression, gene methylation, microRNA expression and comparative genomic hybridization (CGH) analysis in human adrenocortical tissue (normal, adrenocortical adenomas and ACC) samples. A pairwise comparison of normal, adrenocortical adenomas and ACC gene expression profiles with more than four-fold expression differences and an adjusted P-value < 0.05 revealed no major differences in normal versus adrenocortical adenoma whereas there are 808 and 1085, respectively, dysregulated genes between ACC versus adrenocortical adenoma and ACC versus normal. The majority of the dysregulated genes in ACC were downregulated. By integrating the CGH, gene methylation and expression profiles of potential miRNAs with the gene expression of dysregulated genes, we found that there are higher alterations in ACC versus normal compared to ACC versus adrenocortical adenoma. Importantly, we identified several novel molecular pathways that are associated with dysregulated genes and further experimentally validated that oncostatin m signaling induces caspase 3 dependent apoptosis and suppresses cell proliferation. Finally, we propose that there is higher number of genomic changes from normal-to-adenoma-to-carcinoma and identified oncostatin m signaling as a plausible druggable pathway for therapeutics.

Phase I trial of systemic intravenous infusion of interleukin-13-Pseudomonas exotoxin in patients with metastatic adrenocortical carcinoma

Adrenocortical carcinoma (ACC) is a rare but lethal malignancy without effective current therapy for metastatic disease. IL-13-PE is a recombinant cytotoxin consisting of human interleukin-13 (IL-13) and a truncated form of Pseudomonas exotoxin A (PE). The main objectives of this Phase I dose-escalation trial were to assess the maximum-tolerated dose (MTD), safety, and pharmacokinetics (PK) of IL-13-PE in patients with metastatic ACC. Eligible patients had confirmed IL-13 receptor alpha 2 (IL-13Rα2) expressions in their tumors. IL-13-PE at dose of 1-2 μg/kg was administered intravenously (IV) on day 1, 3, and 5 in a 4-week cycle. Six patients received 1 μg/kg and two patients received 2 μg/kg of IL-13-PE. Dose-limiting toxicity was observed at 2 μg/kg, at which patients exhibited thrombocytopenia and renal insufficiency without requiring dialysis. PK analysis demonstrated that at MTD, the mean maximum serum concentration (Cmax ) of IL-13-PE was 21.0 ng/mL, and the terminal half-life of IL-13-PE was 30-39 min. Two (25%) of the eight patients had baseline neutralizing antibodies against PE. Three (75%) of the remaining four tested patients developed neutralizing antibodies against IL-13-PE within 14-28 days of initial treatment. Of the five patients treated at MTD and assessed for response, one patient had stable disease for 5.5 months before disease progression; the others progressed within 1-2 months. In conclusion, systemic IV administration of IL-13-PE is safe at 1 μg/kg. All tested patients developed high levels of neutralizing antibodies during IL-13-PE treatment. Use of strategies for immunodepletion before IL-13-PE treatment should be considered in future trials.

Inhibition of Survivin with YM155 Induces Durable Tumor Response in Anaplastic Thyroid Cancer

PURPOSE

Anaplastic thyroid cancer (ATC) is a rare but lethal malignancy without any effective therapy. The aim of this study is to use a high-throughput drug library screening to identify a novel therapeutic agent that targets dysregulated genes/pathways in ATC.

EXPERIMENTALDESIGN

We performed quantitative high-throughput screening (qHTS) in ATC cell lines using a compound library of 3,282 drugs. Dysregulated genes in ATC were analyzed using genome-wide expression analysis and immunohistochemistry in human ATC tissue samples and ATC cell lines. In vitro and in vivo studies were performed for determining drug activity, effectiveness of targeting, and the mechanism of action.

RESULTS

qHTS identified 100 active compounds in three ATC cell lines. One of the most active agents was the first-in-class survivin inhibitor YM155. Genome-wide expression analysis and immunohistochemistry showed overexpression of survivin in human ATC tissue samples, and survivin was highly expressed in all ATC cell lines tested. YM155 significantly inhibited ATC cellular proliferation. Mechanistically, YM155 inhibited survivin expression in ATC cells. Furthermore, YM155 treatment reduced claspin expression, which was associated with S-phase arrest in ATC cells. In vivo, YM155 significantly inhibited growth and metastases and prolonged survival.

CONCLUSIONS

Our data show that YM155 is a promising anticancer agent for ATC and that its target, survivin, is overexpressed in ATC. Our findings support the use of YM155 in clinical trials as a therapeutic option in advanced and metastatic ATC.

ZNF367 inhibits cancer progression and is targeted by miR-195

Background

Several members of the zinc finger protein family have been recently shown to have a role in cancer initiation and progression. Zinc finger protein 367 (ZNF367) is a member of the zinc finger protein family and is expressed in embryonic or fetal erythroid tissue but is absent in normal adult tissue.

Methodology/Principal Findings

We show that ZNF367 is overexpressed in adrenocortical carcinoma, malignant pheochromocytoma/paraganglioma and thyroid cancer as compared to normal tissue and benign tumors. Using both functional knockdown and ectopic overexpression in multiple cell lines, we show that ZNF367 inhibits cellular proliferation, invasion, migration, and adhesion to extracellular proteins in vitro and in vivo. Integrated gene and microRNA expression analyses showed an inverse correlation between ZNF367 and miR-195 expression. Luciferase assays demonstrated that miR-195 directly regulates ZNF367 expression and that miR-195 regulates cellular invasion. Moreover, integrin alpha 3 (ITGA3) expression was regulated by ZNF367.

Conclusions/Significance

Our findings taken together suggest that ZNF367 regulates cancer progression.

The Hippo effector Yorkie controls normal tissue growth by antagonizing scalloped-mediated default repression

The Hippo tumor suppressor pathway restricts tissue growth by inactivating the transcriptional coactivator Yki. Although Sd has been implicated as a DNA-binding transcription factor partner for Yki and can genetically account for gain-of-function Yki phenotypes, how Yki regulates normal tissue growth remains a long-standing puzzle because Sd, unlike Yki, is dispensable for normal growth in most Drosophila tissues. Here we show that the yki mutant phenotypes in multiple developmental contexts are rescued by inactivation of Sd, suggesting that Sd functions as a default repressor and that Yki promotes normal tissue growth by relieving Sd-mediated default repression. We further identify Tgi as a cofactor involved in Sd's default repressor function and demonstrate that the mammalian ortholog of Tgi potently suppresses the YAP oncoprotein in transgenic mice. These findings fill a major gap in Hippo-mediated transcriptional regulation and open up possibilities for modulating the YAP oncoprotein in cancer and regenerative medicine.

Genetic and pharmacological disruption of the TEAD-YAP complex suppresses the oncogenic activity of YAP

The Drosophila TEAD ortholog Scalloped is required for Yki-mediated overgrowth but is largely dispensable for normal tissue growth, suggesting that its mammalian counterpart may be exploited for selective inhibition of oncogenic growth driven by YAP hyperactivation. Here we test this hypothesis genetically and pharmacologically. We show that a dominant-negative TEAD molecule does not perturb normal liver growth but potently suppresses hepatomegaly/tumorigenesis resulting from YAP overexpression or Neurofibromin 2 (NF2)/Merlin inactivation. We further identify verteporfin as a small molecule that inhibits TEAD-YAP association and YAP-induced liver overgrowth. These findings provide proof of principle that inhibiting TEAD-YAP interactions is a pharmacologically viable strategy against the YAP oncoprotein.