Abstract 2592: Helicobacter pylori-induced FGFR4 mediates nuclear accumulation of NRF2 in gastric tumorigenesis

Background: Fibroblast growth factor receptor 4 (FGFR4) is a member of the transmembrane tyrosine kinase receptor family and has been linked to a variety of malignancies. NRF2 (Nuclear factor-erythroid 2-related factor) is a cytoprotective factor and a critical regulator in the antioxidant response pathway. In this study, we sought to uncover novel functions of FGFR4 and its role in regulating the antioxidant response in gastric carcinogenesis.

Methods and Results: Using western blot and immunofluorescence, H. pylori infection in gastric cancer cell lines demonstrated high levels of reactive oxygen species and induction of both FGFR4 and NRF2. Using Flow cytometry, FGFR4 silencing resulted in decrease of NRF2 with a significant spike in ROS levels and an increase in DNA damage and cell death. FGFR4 knockdown showed a significant decrease in NRF2 transcriptional activity as measured by NRF2 ARE luciferase reporter assay and resulted in reduced mRNA levels of HO-1 (Heme Oxygenase-1), which is a classical target of NRF2. These results were confirmed by immunofluorescence showing a significant increase of nuclear accumulation of NRF2 after H. pylori infection which was abolished after FGFR4 knockdown. Similar results were found using recombinant protein FGF19, a FGFR4 ligand. C57/B6 wild-type mice were infected with the pylori strain (PMSS1). An increase in FGFR4, NRF2, and HO-1 was seen by immunofluorescence, Western blot, and quantitative real-time PCR in H. pylori-infected mice vs control mice. We observed a reduction in NRF2 in our in vitro and in vivo models using H3B-6527, a specific FGFR4 inhibitor. We also discovered an association between an increase in FGFR4 and P62 protein expressions and NRF2 protein stability. We detected a significant increase in FGFR4, NRF2, and HO1 in dysplastic and neoplastic gastric lesions using the TFF1-KO mouse model which was further aggravated by H. pylori infection. In terms of the mechanism, utilizing proximity ligation and immunoprecipitation assays, we found that FGFR4 binds to P62 to inhibit the interaction between NRF2 and KEAP1, allowing NRF2 to avoid degradation facilitating its translocation and accumulation in the nucleus.

Conclusion: These findings revealed that FGFR4 has a unique functional role in promoting gastric carcinogenesis by mediating accumulation and activation of the NRF2 antioxidant response. The use of FGFR4 inhibitors is a viable treatment option that warrants further research in patients with gastric cancer.

Citation Format: Nadeem S. Bhat, Mohammed Soutto, Xing Zhang, Zheng Chen, Ahmed Gomaa, Marwah Al-Mathkour, Selma Maacha, Heng Lu, Dunfa Peng, Zekuan Xu, Wael El-Rifai. Helicobacter pylori-induced FGFR4 mediates nuclear accumulation of NRF2 in gastric tumorigenesis [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 2592.

Abstract 5849: Activation of STAT3 is mediated by FGFR4 induction via SRC signaling after H. pylori infection

Background: Gastric cancer is considered the 5th most common form of cancer and 4th leading cause of cancer-related deaths worldwide. Due to the late stage of diagnosis, gastric cancer carries poor prognosis and poor overall survival. Infection with H. pylori is the strongest known risk factor. Fibroblast Growth Factor Receptor 4 (FGFR4) belongs to a family of highly conserved tyrosine kinases. This study investigated the molecular mechanism of FGFR4 regulation in response to H. pylori infection.

Methods and Results: Among all the FGFRs, FGFR4 mRNA expression level was the most significantly elevated in human gastric cancer samples as compared to normal samples, using Real-time qPCR. These results were confirmed using the TCGA and Geo database analysis, confirming that FGFR4 is highly expressed in gastric cancer. Using western blot, we found that FGFR4 is significantly expressed in dysplasia and adenocarcinoma lesions in the TFF1-KO gastric cancer mouse model. Following infection with H. pylori in in-vitro (J166, 7.13) and in-vivo (PMSS1) models, we detected a significant increase in the expression of FGFR4 at the protein and mRNA levels. We also detected activation of STAT3 in human gastric cell lines and mice gastric tissues. Furthermore, analysis of FGFR4 promoter revealed several putative binding sites for STAT3. To confirm that FGFR4 expression is dependent upon STAT3 activation, we performed ChIP assay and confirmed direct functional binding of STAT3 on FGFR4 promoter. Using the FGF19, the ligand for FGFR4, we found that FGF19-FGFR4 axis played a vital role in activating STAT3 through an SRC-dependent mechanism and discovered that there is a feedforward activation loop between FGFR4 and STAT3. Functionally, we found that FGFR4 protected against H. pylori-induced DNA damage and cell death.

Conclusion: Our study established a feedforward activation loop between FGFR4 and STAT3 in response to H. pylori infection and FGFR4 could be a possible druggable moiety for future therapies in gastric cancer.

Citation Format: Nadeem S. Bhat, Mohammed Soutto, Xing Zhang, Zheng Chen, Shoumin Zhu, Heng Lu, Dunfa Peng, Zekuan Xu, Wael El-Rifai. Activation of STAT3 is mediated by FGFR4 induction via SRC signaling after H. pylori infection [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 5849.

Role of the PI3K/Akt pathway in cadmium induced malignant transformation of normal prostate epithelial cells

This study investigated the role of the PI3K/Akt pathway in cadmium (Cd) induced malignant transformation of normal prostate epithelial (PWR1E and RWPE1) cells. Both PWR1E and RWPE1 cells were exposed to 10 μM Cd for one year and designated as Cd-PWR1E and Cd-RWPE1. Cd-RWPE1 cells robustly formed tumors in athymic nude mice. Functionally, Cd-exposure induced tumorigenic attributes indicated by increased wound healing, migration and invasion capabilities in both cell lines. RT²-array analysis revealed many oncogenes including P110α, Akt, mTOR, NFKB1 and RAF were induced whereas tumor suppressor (TS) genes were attenuated in Cd-RWPE1. This was validated by individual quantitative-real-time-PCR at transcriptional and by immunoblot at translational levels. These results were consistent in Cd-PWR1E vs parental PWR1E cells. Gene Set Enrichment Analysis revealed that five prostate cancer (PCa) related pathways were enriched in Cd-exposed cells compared to their normal controls. These pathways include the KEGG- Pathways in cancer, Prostate Cancer Pathway, ERBB, Apoptosis and MAPK pathways. We selected up- and down-regulated genes randomly from the PI3K/Akt pathway array and profiled these in the TCGA/GDC prostate-adenocarcinoma (PRAD) patient cohort. An upregulation of oncogenes and downregulation of TS genes was observed in PCa compared to their normal controls. Taken together, our study reveals that the PI3K/Akt signaling is one of the main molecular pathways involved in Cd-driven transformation of normal prostate epithelial cells to malignant form. Understanding the molecular mechanisms involved in the Cd-driven malignant transformation of normal prostate cells will provide a significant insight to develop better therapeutic strategies for Cd-induced prostate cancer.

LncRNA CDKN2B-AS1/miR-141/cyclin D network regulates tumor progression and metastasis of renal cell carcinoma

The molecular heterogeneity of renal cell carcinoma (RCC) complicates the therapeutic interventions for advanced metastatic disease and thus its management remains a significant challenge. This study investigates the role of the lncRNA CDKN2B-AS1 and miR-141-3p interactions in the progression and metastasis of kidney cancer. Human renal cancer cell lines (ACHN and Caki1), normal RPTEC cells, tissue cohorts, and a series of in vitro assays and in vivo mouse model were used for this study. An overexpression of CDKN2B-AS1 was observed in RCC compared to normal samples in TCGA and our in-house SFVAMC tissue cohorts. Reciprocally, we observed reduced expression of miR-141 in RCC compared to normal in the same cohorts. CDKN2B-AS1 shares regulatory miR-141 binding sites with CCND1 and CCND2 genes. Direct interactions of CDKN2B-AS1/miR-141/Cyclin D1-D2 were confirmed by RNA immunoprecipitation and luciferase reporter assays indicating that CDKN2B-AS1/miR-141/Cyclin D1-D2 acts as a ceRNA network in RCC. Functionally, attenuation of CDKN2B-AS1 and/or overexpression of miR-141 inhibited proliferation, clonogenicity, migration/invasion, induced apoptosis in vitro and suppressed tumor growth in xenograft mouse model. Further, overexpression of CDKN2B-AS1 is positively correlated with poor overall survival of RCC patients. Expression of miR-141 also robustly discriminated malignant from non-malignant tissues and its inhibition in normal RPTEC cells induced pro-cancerous characteristics. CDKN2B-AS1 attenuation or miR-141 overexpression decreased CCND1/CCND2 expression, resulting in reduced RAC1/pPXN that are involved in migration, invasion and epithelial-mesenchymal transition. This study, for the first time, deciphered the role of CDKN2B-AS1/miR-141/Cyclin D axis in RCC and highlights this network as a promising therapeutic target for the regulation of EMT driven metastasis in RCC.

Activation of the Erk/MAPK signaling pathway is a driver for cadmium induced prostate cancer

PURPOSE

Cadmium (Cd) is reported to be associated with carcinogenesis. The molecular mechanisms associated with Cd-induced prostate cancer (PCa) remain elusive.

MATERIALS AND METHODS

RWPE1, PWR1E and DU 145 cells were used. RT2 Profiler Array, real-time-quantitative-PCR, immunofluorescence, cell cycle, apoptosis, proliferation and colony formation assays along with Gene Set Enrichment Analysis (GSEA) were performed.

RESULT

Chronic Cd exposure of non-malignant RWPE1 and PWR1E cells promoted cell survival, proliferation and colony formation with inhibition of apoptosis. Even a two-week Cd exposure of PCa cell line (DU 145) significantly increased the proliferation and decreased apoptosis. RT2 profiler array of 84 genes involved in the Erk/MAPK pathway revealed induction of gene expression in Cd-RWPE1 cells compared to RWPE1. This was confirmed by individual TaqMan gene expression analysis in both Cd-RWPE1 and Cd-PWR1E cell lines. GSEA showed an enrichment of the Erk/MAPK pathway along with other pathways such as KEGG-ERBB, KEGG-Cell Cycle, KEGG-VEGF, KEGG-Pathways in cancer and KEGG-prostate cancer pathway. We randomly selected upregulated genes from Erk/MAPK pathway and performed profile analysis in a PCa data set from the TCGA/GDC data base. We observed upregulation of these genes in PCa compared to normal samples. An increase in phosphorylation of the Erk1/2 and Mek1/2 was observed in Cd-RWPE1 and Cd-PWR1E cells compared to parental cells, confirming that Cd-exposure induces activation of the Erk/MAPK pathway.

CONCLUSION

This study demonstrates that Erk/MAPK signaling is a major pathway involved in Cd-induced malignant transformation of normal prostate cells. Understanding these dominant oncogenic pathways may help develop optimal therapeutic strategies for PCa.

Minimally invasive plate osteosynthesis (MIPO) in AO/OTA type B displaced clavicle fractures

INTRODUCTION

Open reduction and plate fixation is known to reduce chances of malunion and symptomatic nonunion in displaced middle-third clavicle fractures. However, this treatment modality is also associated with several complications, such as hardware irritation, numbness around the surgical scar, infection, nonunion and implant failure. The minimally invasive plate osteosynthesis (MIPO) technique may reduce these complications.

OBJECTIVE

To study clinical, radiological and functional outcomes of MIPO in AO/OTA type B displaced clavicle fractures and report any complications.

MATERIALS AND METHODS

A total of 22 patients underwent internal fixation of acute displaced AO/OTA type B clavicle fractures from Jan 2014 to Dec 2015 by MIPO using locking compression plates. Patients were followed up at a regular interval and assessed clinically and radiologically. The clavicle length difference was measured. Functional assessment was done at the end of 2 year using constant shoulder score (CSS) and disability of the arm, shoulder and hand score (Quick DASH) and complications if any were noted.

RESULTS

All fractures united at a mean of 12.5 weeks. One (4.5%) patient had numbness around the surgical scar. None of the patients had wound-related complications. In four patients, hardware irritation was noted. The difference in clavicle length was not significant. All patients had excellent CSS and Quick DASH score at the final follow-up.

CONCLUSION

Internal fixation of displaced AO/OTA type B clavicle fractures by MIPO showed high fracture union rates and good functional outcomes.

Activation of STAT3 signaling is mediated by TFF1 silencing in gastric neoplasia

TFF1, a secreted protein, plays an essential role in keeping the integrity of gastric mucosa and its barrier function. Loss of TFF1 expression in the TFF1-knockout (KO) mouse leads to a pro-inflammatory phenotype with a cascade of gastric lesions that include low-grade dysplasia, high-grade dysplasia, and adenocarcinomas. In this study, we demonstrate nuclear localization of p-STAT^Y705, with significant overexpression of several STAT3 target genes in gastric glands from the TFF1-KO mice. We also show frequent loss of TFF1 with nuclear localization of STAT3 in human gastric cancers. The reconstitution of TFF1 protein in human gastric cancer cells and 3D gastric glands organoids from TFF1-KO mice abrogates IL6-induced nuclear p-STAT3^Y705 expression. Reconstitution of TFF1 inhibits IL6-induced STAT3 transcription activity, suppressing expression of its target genes. TFF1 blocks IL6Rα-GP130 complex formation through interfering with binding of IL6 to its receptor IL6Rα. These findings demonstrate a functional role of TFF1 in suppressing gastric tumorigenesis by impeding the IL6-STAT3 pro-inflammatory signaling axis.

Trefoil factor 1 (TFF1) is a protein secreted by the gastric mucosa that protects against gastric tumourigenesis. Here, the authors show that TFF1 inhibits the oncogenic inflammatory response and IL-6-mediated STAT3 activation by interfering with the binding of IL6 to its receptor IL6Rα.

Abstract LB-328: Loss of TFF1 leads to activation of RAGE in mouse and human gastric tumorigenesis

Background: The receptor for advanced glycation end products (RAGE) is a central signaling molecule in the innate immune system and is highly expressed in various cancers including gastric cancer. RAGE is a pattern recognition receptor that binds to multiple ligands leading to its activation and onset of pro-inflammatory response. Trefoil factor 1 (TFF1) is a small secreted protein expressed in the gastrointestinal tract which plays a key role in protection of gastric mucosal membrane and provides protection from injury and damage, therefore acts as tumor suppressor gene. In this study we investigated the role of TFF1 in regulation and degradation of RAGE receptor in vivo and in vitro.

Material and Results: Using quantitative real-time PCR, we observed significant increase of RAGE expression in gastric tissue from Tff1 knockout from non-dysplastic lesion; this increase of expression of RAGE was more notable in dysplastic samples, as compared to normal tissues (p<0.001). The Tff1-KO mice tissues with gastritis and low grade dysplasia (LGD) and high grade dysplasia (HGD) showed significantly progressive higher expression of RAGE, as compared to normal tissues (p<0.001). Analysis of human tissue samples demonstrated significant overexpression of RAGE, as compared to normal gastric tissues (p=0.01). Furthermore, we analyzed paired tumor and normal samples, and we found a significant up-regulation of RAGE mRNA expression in tumors compared to their corresponding normal samples (p=0.01). We also detected an inverse relationship between TFF1 and RAGE levels in mouse and human tissue samples. We next determined the levels of RAGE ligands, S100A2 and A4. The results showed significant increase in expression levels of S100A2 and A4 in human and mouse neoplastic gastric lesions, as compared to normal tissue samples (P<.01). To determine a causal relationship between TFF1 and RAGE, we used in vitro cell models. Using Western blot and RT-PCR analysis, the reconstitution of TFF1 in AGS cells showed a decrease in expression levels of RAGE, S100A2, and A4, as compared to control cells. Treatment of cancer cell lines (AGS, MKN28, and MKN45) with RAGE inhibitor Azeliragon led to significant reduction in cell viability with IC50 range AGS= 1.65µM, MKN28=1.22µM, MKN45= 1.37µM .

Conclusion: Our data demonstrate, for the first time, that high levels of RAGE and its ligands S100A2 and A4 are mechanistically related to TFF1 levels. RAGE inhibitors demonstrated a therapeutic efficacy in pre-clinical in vitro models. Additional in vitro and in vivo studies are planned to determine the functional, mechanistic and therapeutic outcomes of RAGE in gastric tumorigenesis.

Citation Format: Nadeem S. Bhat, Mohammed Soutto, Zheng Chen, Shoumin Zhu, Huma Naz, Ahmed Gomaa, Sen Wang, Barry I. Hudson, El-Rifai Wael. Loss of TFF1 leads to activation of RAGE in mouse and human gastric tumorigenesis [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 LB-328.

Abstract 4659: Cadmium induced malignant transformation involves activation of the Erk/MAPK pathway

Cadmium (Cd) is a chemical pollutant of the natural and occupational environment and is reported to be associated with human carcinogenesis. The molecular mechanisms associated with Cd-induced prostate cancer remain elusive. This study provides evidence that Erk/MAPK signaling is a carcinogenic molecular fingerprint for Cd induced prostate cancer. Cd exposed RWPE1 (Cd-RWPE1) cells robustly formed tumors in nude mice. Functionally, chronic Cd exposure of RWPE1 cells promoted cell survival, proliferation and colony formation with inhibition of apoptosis. RT2 PCR array analysis of 84 genes involved in the Erk/MAPK pathway revealed induction of gene expression in Cd-RWPE1 cells compared to RWPE1. This was confirmed by individual TaqMan gene expression analysis. Gene Set Enrichment Analysis (GSEA) for differentially expressed genes in Cd-RWPE1 showed an enrichment of the Erk/MAPK pathway along with other pathways such as KEGG-ERBB, KEGG-Cell Cycle, KEGG-VEGF, KEGG-Pathways in cancer and KEGG-prostate cancer pathway. We randomly selected upregulated genes from the Erk/MAPK pathway and performed profile analysis in a prostate adenocarcinoma data set (n=534) from the TCGA/GDC data base. We observed upregulation of these genes in prostate cancer compared to normal prostate samples. Taken together, these data reveal that Erk/MAPK signaling is a major pathway involved in Cd-induced malignant transformation of normal prostate epithelial cells. Understanding the dominant oncogenic pathways involved in the malignant transformation of normal prostate epithelial cells may help develop optimal therapeutic strategies for prostate cancer.

Citation Format: Pritha Dasgupta, Priyanka Kulkarni, Nadeem S. Bhat, Ravi Gupta, Yutaka Hashimoto, Sharanjot Saini, Altaf A. Dar, Varahram Shahryari, Soichiro Yamamura, Yuichiro Tanaka, Marisa Shiina, Rajvir Dahiya, Shahana Majid. Cadmium induced malignant transformation involves activation of the Erk/MAPK pathway [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 4659.

Abstract 3549: Elevated miR-141-3p inhibits renal cell carcinoma aggressiveness by targeting epithelial-to-mesenchymal transition pathway

Objective: Clear cell renal cell carcinoma (ccRCC), a common histological subtype of renal cell carcinoma (RCC) are categorized by their aggressive nature and comprise 90% of metastatic RCCs. Despite recent advances, management of the disease in the advanced metastatic phase is a significant challenge. Expression of miR-141-3p (miR-141) is low and function as tumor suppressor in various cancers. However, its association with long non-coding RNAs (lncRNAs) in RCC is not well understood. This study shows that miR-141 interacts with lncRNAs, and plays vital role in the regulation of stemness and epithelial-to-mesenchymal transition (EMT) in RCC.

Experimental Design: Human renal cancer cell lines (ACHN and Caki-1), normal renal epithelial cells, RPTEC and tumor tissues were used for this study. We analyzed the expression of miR-141 in tissue samples and cell lines, and studied the function of miR-141 in kidney cancer progression using in vitro and in vivo models. Statistical analysis was performed to determine the clinical significance of miR-141 in kidney cancer patients.

Results: Reduced expression of miR-141 was observed in ccRCC clinical specimens and cell lines. To elucidate the epigenetic role of miR-141 silencing in RCC, methylation status of CpG islands in its putative promoter region was analyzed. Result showed significant increase in miR-141 expression after 5-Aza-CdR treatment indicating that promoter hypermethylation is responsible for its inactivation. Ectopic expression of miR-141 reduced cell proliferation, clonogenicity, migration, invasion and induced apoptosis and cell cycle arrest compared to controls. An increase in cleaved PARP, cleaved caspase-3 and epithelial marker (CLDN1) was observed with a concomitant decrease in stemness (KLF4, Nanog) and EMT markers (FN1, VIM). We further investigated the biological significance of miR-141 in RCC. Loss of miR-141 function in RPTEC cells induced pro-cancerous characteristics. In addition, we examined lncRNAs (CDKN2B-As1, PCAT1 and PVT1) that bind to miR-141 and are overexpressed in RCC clinical samples compared to controls. Reduced expression of these lncRNAs was observed in RCC cells with overexpression of miR-141, supporting the notion that miR-141 interacts with these lncRNAs in RCC. Finally, in vivo experiment in nude mice revealed that intra-tumoral administration of miR-141 in the established tumors significantly suppressed tumor growth compared to controls. Furthermore, statistical analysis of patient samples showed that miR-141 may serve as a RCC diagnostic biomarker.

Conclusion: Our results demonstrate that miR-141 overexpression inhibits RCC progression and inhibits epithelial-to-mesenchymal transition. These studies also show that miR-141 may be a useful RCC biomarker for early detection and monitoring RCC progression.

Citation Format: Pritha Dasgupta, Priyanka Kulkarni, Shahana Majid, Varahram Shahryari, Nadeem S. Bhat, Yutaka Hashimoto, Marisa Shiina, Guoren Deng, Sharanjot Saini, Soichiro Yamamura, Yuichiro Tanaka, Rajvir Dahiya. Elevated miR-141-3p inhibits renal cell carcinoma aggressiveness by targeting epithelial-to-mesenchymal transition pathway [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 3549.

Abstract 5040: Involvement of PI3K/Akt pathway in cadmium triggered aggressive prostate cancer

Cadmium (Cd) has been implicated in cancer development and classified as a type I carcinogen by the International Agency for Cancer Research. The etiology of prostate cancer development is associated with multitude of causative risk factors including exposure to cadmium. However, the molecular mechanisms associated with Cd-induced prostate cancer remain elusive. This study provides evidence that PI3K/Akt signaling is a major molecular pathway involved in Cd induced malignant transformation of normal prostate epithelial cells. Functionally, Cd exposure induced aggressive behavior as indicated by increased proliferation, migration and invasion in Cd-RWPE1 cells compared to parental RWPE1. PI3K/Akt pathway is constitutively activated in prostate cancer driving the most aggressive forms of cancer and metastasis. Consistent with these findings, the RT2 PCR array analysis of 84 genes involved in the PI3K/Akt pathway revealed induction of gene expression in catalytic units (P110α, Akt, mTOR, NFKB1, RAF etc.) with a concomitant reduction in expression of regulatory units (PIK3R1, PIK3R2, PTEN etc.) of the PI3K/Akt pathway in Cd-RWPE1 cells compared to parental RWPE1. This was confirmed by individual quantitative real-time PCR analysis using TaqMan gene expression assay probes. Effect of Cd on the translation of the PI3K/Akt pathway genes was examined by immunoblot assays. Gene Set Enrichment Analysis (GSEA) for differentially expressed genes in Cd-RWPE1 showed 5 overlapping pathways that were enriched in Cd-treated cells (Cd-RWPE1) and negatively correlated with parental RWPE1. The overlapping pathways include KEGG Apoptosis pathway (ES=0.56, NES=1), KEGG ERBB pathway (ES=0.25, NES=1), KEGG MAPK pathway (ES=0.48, NES=1), KEGG Pathways in cancer (ES=0.33, NES=1) and KEGG Prostate Cancer pathway (ES=0.35, NES=1). Interestingly, all these pathways are implicated in prostate cancer progression and metastasis. We randomly selected up- and down-regulated genes from the PI3K/Akt pathway in PCR array and performed profile analysis in a prostate adenocarcinoma data set (n=534) from the TCGA/GDC data base. We observed upregulation of the oncogenes along with downregulation of tumor suppressors in prostate cancer compared to normal prostate samples. Taken together, these data reveal that Cd exposure induced aggressive malignant characteristics in normal prostate epithelial cells via modulation of the PI3K/Akt signaling pathway. Understanding the molecular mechanisms involved in the malignant transformation of normal prostate epithelial cells may help develop optimal therapeutic strategies for advanced prostate cancer.

Citation Format: Priyanka Kulkarni, Pritha Dasgupta, Nadeem S. Bhat, Yutaka Hashimoto, Sharanjot Saini, Altaf A. Dar, Varahram Shahryari, Marisa Shiina, Soichiro Yamamura, Yuichiro Tanaka, Rajvir Dahiya, Shahana Majid. Involvement of PI3K/Akt pathway in cadmium triggered aggressive prostate 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 5040.

TFF1 antagonizes TIMP-1 mediated proliferative functions in gastric cancer

Tissue inhibitor matrix metalloproteinase-1 (TIMP1) is one of four identified members of the TIMP family. We evaluated the role of TIMP1 in gastric cancer using human and mouse tissues along with gastric organoids and in vitro cell models. Using quantitative real-time RT-PCR, we detected significant overexpression of TIMP1 in the human gastric cancer samples, as compared to normal stomach samples (P < 0.01). We also detected overexpression of Timp1 in neoplastic gastric lesions of the Tff1-knockout (KO) mice, as compared to normal stomach tissues. Reconstitution of TFF1 in human gastric cancer cell lines led to a significant decrease in the mRNA expression level of TIMP1 (P < 0.05). In vitro analysis demonstrated that TIMP1 mRNA expression is induced by TNF-α and activation of NF-κB whereas inhibition of NF-κB using BAY11-7082 led to inhibition of NF-κB and downregulation of TIMP1. Western blot analysis confirmed the decrease in TIMP1 protein level following reconstitution of TFF1. By using immunofluorescence, we showed nuclear localization of NF-κB and expression of TIMP1 in gastric organoids established from the Tff1-KO stomach where reconstitution of Tff1 using recombinant protein led to a notable reduction in the expression of both NF-κB and TIMP1. Using EDU assay, as a measure of proliferating cells, we found that TIMP1 promotes cellular proliferation whereas TFF1 reconstitution leads to a significant decrease in cellular proliferation (P < 0.05). In summary, our findings demonstrate overexpression of TIMP1 in mouse and human gastric cancers through NF-kB-dependent mechanism. We also show that TFF1 suppresses NF-κB and inhibits TIMP1-mediated proliferative potential in gastric cancer.

Elevated miR-182-5p Associates with Renal Cancer Cell Mitotic Arrest through Diminished MALAT-1 Expression

The molecular heterogeneity of clear cell renal carcinoma (ccRCC) makes prediction of disease progression and therapeutic response difficult. Thus, this report investigates the functional significance, mechanisms of action, and clinical utility of miR-182-5p and metastasis-associated lung adenocarcinoma transcript 1 (MALAT1/NEAT2), a long noncoding RNA (lncRNA), in the regulation of kidney cancer using human kidney cancer tissues as well as in vitro and in vivo model systems. Profiling of miR-182-5p and MALAT-1 in human renal cancer cells and clinical specimens was done by quantitative real-time PCR (qPCR). The biological significance was determined by series of in vitro and in vivo experiments. The interaction between miR-182-5p and MALAT-1 was investigated using luciferase reporter assays. In addition, the effects of miR-182-5p overexpression and MALAT-1 downregulation on cell-cycle progression were assessed in ccRCC cells. The data indicate that miR-182-5p is downregulated in ccRCC; the mechanism being CpG hypermethylation as observed from 5-Aza CdR treatment that decreased promoter methylation and expression of key methylation regulatory genes like DNMT1, DNMT3a, and DNMT3b Overexpression of miR-182-5p-inhibited cell proliferation, colony formation, apoptosis, and led to G₂-M-phase cell-cycle arrest by directly targeting MALAT-1 Downregulation of MALAT-1 led to upregulation of p53, downregulation of CDC20, AURKA, drivers of the cell-cycle mitotic phase. Transient knockdown of MALAT-1 mimicked the effects of miR-182-5p overexpression. Finally, overexpression of miR-182-5p decreased tumor growth in mice, compared with controls; thus, demonstrating its antitumor effect in vivo Implications: This is the first study that offers new insight into role of miR-182-5p/MALAT-1 interaction on inhibition of ccRCC progression. Mol Cancer Res; 16(11); 1750-60. ©2018 AACR.

Abstract 2457: Epithelial-to-mesenchymal transition and stemness: Key targets of HOTAIR-miR-203 interaction in renal cell carcinoma

Background: Tumor metastasis and recurrence are major obstacles in renal cell carcinoma (RCC) treatment. RCC aggressiveness is highly associated with stemness and epithelial-to-mesenchymal transition (EMT) which involves increased cellular migration, invasion, inhibition of apoptosis and senescence. HOX transcript antisense RNA (HOTAIR), a lncRNA, is reported to be over-expressed, whereas miR-203 has low expression and is a tumor suppressor in various cancers. However, their association and role in RCC is not well understood. The aim of the present study was to examine the interaction of HOTAIR and miR-203 in the regulation of stemness and EMT in RCC.

Experimental Procedure: ACHN, Caki-1 (human RCC cell lines), normal renal epithelial cells HK-2 and clinical specimens were used for this study. Profiling of HOTAIR and miR203 expression were done by quantitative real-time PCR and luciferase assay was performed to confirm their interaction. Attenuation of HOTAIR (25nM siRNA) and overexpression of miR-203 (10nM mimic) for 72 hours were used for functional studies. The biological role of miR-203 and its interaction with HOTAIR was also investigated using nude mouse models.

Results: HOTAIR was observed to be overexpressed in RCC cell-lines and clinical specimens whereas, miR-203 was significantly under-expressed when compared to normal cells and tissues. Overexpression of miR-203 altered the cell cycle, inhibited epithelial-to-mesenchymal transition (EMT) and decreased cell proliferation along with induction of epithelial marker proteins and decrease in mesenchymal and stemness marker proteins. Conversely, knockdown of miR-203 in non-malignant HK-2 cells induced pro-cancerous characteristics. Direct binding of miR-203 to HOTAIR was shown by RNA immunoprecipitation and luciferase assay. Attenuation of HOTAIR expression reduced cell migration, invasion, and induced apoptosis, mimicking the effects of miR-203 overexpression. Administration of miR-203 mimic to established tumors in nude mice significantly suppressed tumor growth compared to controls.

Conclusion: Our results show that HOTAIR-miR-203 interaction inhibits EMT and stemness to regulate RCC progression. Statistical analysis of the clinicopathological data from kidney cancer patients suggests that HOTAIR and miR-203 may be useful in RCC diagnostics and therapeutics.

Citation Format: Pritha Dasgupta, Priyanka Kulkarni, Shahana Majid, Varahram Shahryari, Yutaka Hashimoto, Nadeem S. Bhat, Marisa Shiina, Guoren Deng, Sharanjot Saini, Soichiro Yamamura Yamamura, Yuichiro Tanaka, Rajvir Dahiya. Epithelial-to-mesenchymal transition and stemness: Key targets of HOTAIR-miR-203 interaction in renal cell carcinoma [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 2457.

Abstract 1111: Role of a prometastatic miRNA as a negative regulator of the key metastasis suppressor genes in renal cell carcinoma

Background: Renal cell carcinoma (RCC) is among the ten leading cancer types in United States. The 5-year relative survival rate of regional or localized RCC is 65-92%, while that of metastatic RCC is only 12%. Tumor recurrence and metastasis represent two major obstacles in the successful treatment of cancer. Emerging lines of evidence suggest that cancer aggressiveness is associated with epithelial to mesenchymal transition (EMT). Therefore, it is of critical importance to regulate EMT and to develop effective therapeutic strategies for the treatment of recurrent and metastatic cancer. Critical regulators of EMT include transcription repressors and microRNAs that target key proteins involved in EMT. MicroRNAs are implicated in regulating cancer progression and metastasis. Here we show that miR-720 is positively associated with RCC by negatively regulating key metastasis suppressing genes.

Methods: We performed a series of in vitro and in vivo experiments including qRT-PCR, FACS cell cycle and apoptosis, chemotactic transwell migration and invasion, immunoblotting and luciferase reporter assays along with intratumoral xenograft mouse model.

Results: Elevated levels of miR-720 were observed in a panel of RCC cell lines and clinical tissues compared to non-malignant cell line and normal samples. Loss of miR-720 function inhibited proliferation, migration and invasion and induced apoptosis in RCC cell lines in vitro and repressed tumor growth in xenograft mouse model. Conversely, gain of miR-720 function in non-malignant HK-2 cells induced pro-cancerous characteristics. Silencing of miR-720 caused a marked induction in the levels of endogenous αE-catenin and E-cadherin protein levels in anti720 transfected cells compared to control. Whereas, miR-720 overexpression in RCC cell lines reduced activity of a luciferase reporter gene fused to the wild-type αE-catenin or E-cadherin 3' UTR compared to non-specific 3' UTR control indicating that αE-catenin-E-cadherin complex is a direct and functional target of miR-720 in RCC. We also observed attenuation of β-Catenin, CD44 and Akt expression in RCC cells transfected with miR-720 inhibitor compared to control. Further, miR-720 exhibited clinical significance in RCC. Expression of miR-720 significantly distinguished malignant from normal samples. Elevated miR-720 levels positively correlated with higher Fuhrman grade, pathological stage and poor overall survival of RCC patients.

Conclusion: These findings uncover a new regulatory network in RCC involving metastasis-promoting miR-720 that directly targets expression of key metastasis-suppressing proteins E-cadherin and αE-catenin complex. These results suggest that therapeutic regulation of miR-720 may provide an opportunity to regulate EMT and metastasis in RCC.

Citation Format: Nadeem S. Bhat, Altaf A. Dar, Sharanjot Saini, Varahram Shahryari, Soichiro Yamamura, Yuichiro Tanaka, Taku Kato, Yutaka Hashimoto, Marisa Shiina, Priyanka Kulkarni, Pritha Dasgupta, Z Laura Tabatabai, Guoren Deng, Rajvir Dahiya, Shahana Majid. Role of a prometastatic miRNA as a negative regulator of the key metastasis suppressor genes in renal cell carcinoma [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 1111.

MicroRNA-203 Inhibits Long Noncoding RNA HOTAIR and Regulates Tumorigenesis through Epithelial-to-mesenchymal Transition Pathway in Renal Cell Carcinoma

This study aims to investigate the role of miR-203-HOTAIR interaction in the suppression of renal cell carcinoma (RCC). We employed series of in vitro assays such as proliferation, invasion, migration, and colony formation along with in vivo tumor xenograft model. Profiling of miR-203 and HOTAIR expression revealed that miR-203 was significantly underexpressed, whereas HOTAIR was overexpressed in RCC cell lines and clinical specimens compared with normal cell line and tissue. Both miR-203 and HOTAIR expression significantly distinguished malignant from normal tissues and significantly correlated with clinicopathologic characteristics of patients. Overexpression of miR-203 significantly inhibited proliferation, migration, and invasion with an induction of apoptosis and cell-cycle arrest. However, HOTAIR suppression resulted in the similar functional effects in the same RCC cell lines. In silico, RNA-22 algorithm showed a binding site for miR-203 in HOTAIR. We observed a direct interaction between miR-203 and HOTAIR by RNA-immunoprecipitation (RIP) and luciferase reporter assays. We show that miR-203-HOTAIR interaction resulted in the inhibition of epithelial-to-mesenchymal transition (EMT) and metastatic genes as indicated by induction of key metastasis-suppressing proteins E-cadherin, claudin (epithelial markers), and PTEN along with induction of tumor suppressor genes p21 and p27. A significant decrease in vimentin (mesenchymal marker), KLF4, and Nanog (stemness markers) was also observed. This is the first report demonstrating miR-203-mediated regulation of HOTAIR induces tumor suppressor effects in RCC by regulating EMT and metastatic pathway genes. Thus, the study suggests that therapeutic regulation of HOTAIR by miR-203 overexpression may provide an opportunity to regulate RCC growth and metastasis. Mol Cancer Ther; 17(5); 1061-9. ©2018 AACR.

MicroRNA-720 Regulates E-cadherin-αE-catenin Complex and Promotes Renal Cell Carcinoma

miRNAs are implicated in regulating cancer progression and metastasis. Here, we show that miR-720 is positively associated with renal cell carcinoma (RCC). Elevated levels of miR-720 were observed in a panel of RCC cell lines and clinical tissues compared with nonmalignant cell line and normal samples. Loss of miR-720 function inhibited proliferation, migration, and invasion and induced apoptosis in RCC cell lines in vitro and repressed tumor growth in xenograft mouse models. Conversely, gain of miR-720 function in nonmalignant HK-2 cells induced procancerous characteristics. Silencing of miR-720 caused a marked induction in the levels of endogenous αE-catenin and E-cadherin protein levels in anti720 transfected cells compared with control, whereas miR-720 overexpression in RCC cell lines reduced activity of a luciferase reporter gene fused to the wild-type αE-catenin or E-cadherin 3'UTR compared with nonspecific 3'UTR control, indicating that αE-catenin-E-cadherin complex is a direct and functional target of miR-720 in RCC. We also observed attenuation of β-catenin, CD44, and Akt expression in RCC cells transfected with miR-720 inhibitor compared with control. Furthermore, miR-720 exhibited clinical significance in RCC. Expression of miR-720 significantly distinguished malignant from normal samples. Elevated miR-720 levels positively correlated with higher Fuhrman grade, pathologic stage, and poor overall survival of RCC patients. These findings uncover a new regulatory network in RCC involving metastasis-promoting miR-720 that directly targets expression of key metastasis-suppressing proteins E-cadherin and αE-catenin complex. These results suggest that therapeutic regulation of miR-720 may provide an opportunity to regulate EMT and metastasis in RCC. Mol Cancer Ther; 16(12); 2840-8. ©2017 AACR.

Abstract LB-326: A novel oncomiR negatively regulates PTEN pathway in prostate cancer

Prostate carcinogenesis involves alterations in several signaling pathways, the most prominent being the PI3K/AKT pathway. This pathway is constitutively active and drives prostate cancer (PCa) progression to advanced metastatic disease. PTEN, a critical tumor and metastasis suppressor gene negatively regulates cell survival, proliferation, migration and angiogenesis via the PI3K/Akt pathway. PTEN is mutated, downregulated/dysfunctional in many cancers and its dysregulation correlates with poor prognosis in PCa. Here, we demonstrate that a novel microRNA, microRNA-4534 (miR-4534) is overexpressed in PCa and show that miR-4534 is hypermethylated in normal tissues and cell lines compared to PCa tissues/cells. miR-4534 exerts its oncogenic effects partly by downregulating the tumor suppressor PTEN gene. Knockdown of miR-4534 impaired cell proliferation, migration/invasion and induced G0/G1 cell cycle arrest and apoptosis in PCa. Suppression of miR-4534 and its effects on tumor growth was confirmed in a xenograft mouse model. We performed parallel experiments in non-cancer RWPE1 cells by overexpessing miR-4534 followed by functional assays. Overexpression of miR-4534 induced pro-cancerous characteristics in this non-cancer cell line. Kaplan-Meier and ROC analyses revealed that miR-4534 has potential to independently distinguish malignant from normal tissues and positively correlated with poor overall and PSA recurrence free survival. Taken together, our results show that depletion of miR-4534 in PCa induces a tumor suppressor phenotype partly through induction of PTEN. These results have important implications for identifying and defining the role of new PTEN regulators such as microRNAs in prostate tumorigenesis. Understanding aberrantly overexpressed miR-4534 and its downregulation of PTEN will provide mechanistic insight and therapeutic targets for PCa therapy.

Note: This abstract was not presented at the meeting.

Citation Format: Nadeem S. Bhat, Melissa Colden, Prerna Arora, Altaf A. Dar, Sharanjot Saini, Varahram Shahryari, Soichiro Yamamura, Yuichiro Tanaka, Taku Katu, Yutaka Hashimoto, Marisa Shiina, Priyanka Kulkarni, Pritha Dasgupta, Mitsuho Imai-sumida, Shigekatsu Maekawa, Guoren Deng, Rajvir Dahiya, Shahana Majid. A novel oncomiR negatively regulates PTEN pathway in prostate cancer [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 LB-326. doi:10.1158/1538-7445.AM2017-LB-326

Neurological deficit and canal compromise in thoracolumbar and lumbar burst fractures

PURPOSE

To assess whether canal compromise determines neurological deficit in thoracolumbar and lumbar burst fractures.

METHODS

105 patients aged 17 to 60 (mean, 34) years who had burst fractures in the thoracolumbar (n=82) and lumbar (n=23) regions were included. Fractures were classified according to the Denis classification. The extent of spinal canal compromise was assessed by computed tomography, and the neurological status according to the modified Frankel grading for traumatic paraplegia.

RESULTS

19 (18%) of the patients had no neurological deficit. Of the remaining 86 (82%) with a deficit, 26 had complete paraplegia. The correlation between the type of the burst fracture and the severity of neurological deficit was not significant (Chi squared=10.57, p=0.835). The mean extent of spinal canal compromise in patients with deficits was 50%, whereas in patients with no deficit it was 36%. The difference between the extent of canal compromise and the severity of neurological deficit at the thoracolumbar and lumbar spine was not significant (p=0.08). Further subanalysis revealed a significant correlation at T11 and T12 (p=0.007) but not at the L1 (p=0.42) level.

CONCLUSION

When studying neurological deficit, T11 and T12 injuries should be analysed separately from L1 injuries.