MTA1 Expression Research Articles

Expression of metastasis-associated protein 3 in human brain glioma related to tumor prognosis.

Glioma represents a disparate group of tumors characterized by high invasion ability, and therefore it is of clinical significance to identify molecular markers and therapeutic targets for better clinical management. Previously, metastasis-associated protein family (MTA) is considered to promote tumor cell invasion and metastasis of human malignancies. Recently, the newly identified MTA3 has been shown to play conflicting roles in human malignancies, while the expression pattern and potential clinical significance of MTA3 in human glioma have not been addressed yet. In the present study, we investigated the protein expression of MTA3 by immunohistochemistry assay and analyzed its association with glioma prognosis in 186 cases of patients. Results showed that MTA3 expression was decreased in glioma compared with that in normal brain (P < 0.05). In addition, tumors with high MTA3 expression were more likely to be of low WHO grade (P = 0.005) and reserve of body function (P = 0.014). Survival analysis showed that decreased MTA3 expression was independently associated with unfavorable overall survival of patients (P < 0.001). These results provide the first evidence that MTA3 expression was decreased in human glioma and negatively associated with prognosis of patients, suggesting that MTA3 may play a tumor suppressor role in glioma.

MTA2 enhances colony formation and tumor growth of gastric cancer cells through IL-11.

BackgroundWe have preliminarily reported MTA2 expression in gastric cancer and its biological functions by using knockdown cell models, while the molecular mechanisms of MTA2 in regulating malignant behaviors are still unclear.MethodsMTA2 overexpression models were established by transfection assay in gastric cancer cells BGC-823 and MKN28. Cell proliferation assay, colony formation in soft agar, wound-healing assay and transwell migration assay were performed with MTA2 overexpression and negative control (NC) cells. Subcutaneous xenografts and pulmonary metastasis models by BGC-823/MTA2 and BGC-823/NC cells were used to observe the capacity of growth and metastasis in vivo. Differential gene expression in MTA2 knockdown and overexpression cells was analyzed by microarrays. IL-11, which demonstrated as differential expression in microarray, was detected by real-time PCR, western blot, ELISA and immunohistochemistry staining. Recombinant human IL-11 (rhIL-11) was administrated in cell proliferation and colony formation as rescue assay.ResultsThe numbers of colonies in soft agar were significantly more in BGC-823/MTA2 and MKN28/MTA2 cells, comparing with those in their NC cells. Capabilities of cell proliferation, wound-healing and cell migration were not significantly changed in MTA2 overexpression cells. The sizes of subcutaneous xenografts and pulmonary metastases of BGC-832/MTA2 cells were significantly larger than those in BGC-823/NC group. Differential expression of IL-11 was identified by genome expression microarray both in MTA2 knockdown and overexpression cells. IL-11 expression was elevated in BGC-823/MTA2 cells, whereas reduced in SGC-7901/shMTA2 cells. Administration of rhIL-11 recovered colony formation capacity of SGC-7901/shMTA2 cells.ConclusionsMTA2 overexpression enhances colony formation and tumor growth of gastric cancer cells, but not plays important role in cancer cell migration and metastasis. IL-11 is one of the downstream effectors of MTA2 in regulating gastric cancer cells growth.Electronic supplementary materialThe online version of this article (doi:10.1186/s12885-015-1366-y) contains supplementary material, which is available to authorized users.

Inhibition of invasion and metastasis of human liver cancer HCCLM3 cells by portulacerebroside A

Context: Portulacerebroside A (PCA) is a novel cerebroside compound isolated from Portulaca oleracea L. (Portulacaceae), an edible and medicinal plant distributed in the temperate and tropical zones worldwide.Objective: This study investigates the effects of PCA in human liver cancer HCCLM3 cells on metastasis and invasion.Materials and methods: After the cells were treated with PCA (2.5, 5, and 10 μg/ml) for 6, 12, 24, or 48 h, adhesion, transwell invasion, and scratch tests were conducted and cell functions were evaluated. Western blot and FQ-RT-PCR assays explored the mechanism of PCA-inhibited invasion and metastasis in the cells.Results: The adhesion rate of the cells was suppressed at 0.5 h (79.4 ± 1.0, 68.7 ± 1.3, and 58.1 ± 1.3%, versus 100 ± 1.5% in the control), 1 h (78.2 ± 1.2, 70.9 ± 1.6, and 55.4 ± 1.9%, versus 100 ± 1.2% in the control), and 1.5 h (71.6 ± 1.1, 62.3 ± 0.9, and 50.4 ± 0.9%, versus 100 ± 1.1% in the control). The 24 h invasion ability was decreased (356.6 ± 11.2, 204.0 ± 17.6, and 113.0 ± 9.5%, versus 443.6 ± 15.4% in the control). The migration capability was also restrained by PCA for 24 h (324.8 ± 25.4, 250.4 ± 21.0, and 126.3 ± 10.1, versus 381.6 ± 30.6 in the control) and 48 h (470.3 ± 34.3, 404.0 ± 19.7, and 201.0 ± 15.4, versus 752.0 ± 63.6 in the control). There was an increase in the mRNA and protein expression levels of TIMP-2 and nm23-H1, inhibition in the mRNA expression of MTA1, MMP-2, and MMP-9, and suppression in the protein expression of MTA1, RhoA, Rac1/Cdc42, MMP-2, but not RhoC and MMP-9.Conclusion: PCA suppresses the invasion and metastasis of HCCLM3 cells possibly by modulation of the mRNA and protein expression of related parameters. This is the first study to reveal a new potential therapeutic application of PCA in antimetastatic therapy for liver cancer.

MTA1--a stress response protein: a master regulator of gene expression and cancer cell behavior.

Gene mutation’s role in initiating carcinogenesis has been controversial, but it is consensually accepted that both carcinogenesis and cancer metastasis are gene-regulated processes. MTA1, a metastasis-associated protein, has been extensively researched, especially regarding its role in cancer metastasis. In this review, I try to elucidate MTA1’s role in both carcinogenesis and metastasis from a different angle. I propose that MTA1 is a stress response protein that is upregulated in various stress-related situations such as heat shock, hypoxia, and ironic radiation. Cancer cells are mostly living in a stressful environment of hypoxia, lack of nutrition, and immune reaction attacks. To cope with all these stresses, MTA1 expression is upregulated, plays a role of master regulator of gene expression, and helps cancer cells to survive and migrate out of their original dwelling.

Abstract 3199: Pterostilbene supresses prostate cancer progression in transgenic mice model

Abstract Metastasis-associated protein 1 (MTA1) is a cancer progression-related epigenetic modifier whose overexpression is associated with aggressive prostate cancer (PCa), disease recurrence and metastasis in men. We previously found that MTA1 expression is significantly increased in Pten-null murine cells, and that resveratrol and its analogues inhibit MTA1 expression. In the current study, we used the murine Pten knockout PCa model to evaluate the effect of pterostilbene (PTER) on MTA1-mediated events in PCa progression. Pterostilbene is a potent natural analogue of resveratrol with improved pharmacokinetic properties and superior pharmacological potency. The Pten conditional knockout mice that mimic human disease and provide fast stage-defined development of PCa were fed, starting at 3 weeks of age, with phytoestrogen-free diet AIN 76A and injected daily (i.p.) either with 10% DMSO (control, untreated) or with 10 mg/kg bw PTER until 6, 10, 15 and 25 weeks of age. At necropsy, mouse prostates were formalin-fixed and paraffin-embedded for histological and immunohistochemical analysis. For protein analysis, mouse prostate dissection was performed to distinguish anterior prostate (AP) and dorso-latero-ventral (DLV) lobes. Our results showed that the PTER-treated group had a lower tumor grade and higher incidence of prostate intraepithelial neoplasia (PIN) at the expense of a substantial decrease in adenocarcinoma incidence. Prostate tissues from the PTER-treated group presented a decrese in Ki67 proliferation marker-positive cells and an increase in apoptosis. As potential mechanisms of PTER efficacy, 50-75% decrease in MTA1 and pAkt levels were observed at different time points. In addition, PTER inhibited androgen receptor (AR) expression, especially in the AP. Taken together, our findings suggest that PTER blocks PCa growth and progression at PIN stage in Pten conditional knockout mice model through inhibition of MTA1-Akt axis. Citation Format: Liangfen Zhang, Swati Dhar, Agnes M. Rimando, Avinash Kumar, Janice Lage, Jack R. Lewin, Xu Zhang, Anait S. Levenson. Pterostilbene supresses prostate cancer progression in transgenic mice model. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3199. doi:10.1158/1538-7445.AM2014-3199

MTA1 overexpression induces cisplatin resistance in nasopharyngeal carcinoma by promoting cancer stem cells properties.

Themetastasis-associated gene 1 (MTA1) oncogene hasbeen suggested to be involved in the regulation of cancer progression. However, there is still no direct evidence that MTA1 regulates cisplatin (CDDP) resistance, as well as cancer stem cell properties. In this study, we found that MTA1 was enriched in CNE1/CDDP cells. Knock down of MTA1 in CNE1/CDDP cells reversed CSCs properties and CDDP resistance. However, ectopic expression of MTA1 in CNE1 cells induced CSCs phenotypes and CDDP insensitivity. Interestingly, ectopic overexpression of MTA1-induced CSCs properties and CDDP resistance were reversed in CNE1 cells after inhibition of PI3K/Akt by LY294002. In addition, MTA1 expression and Akt activity in CNE1/CDDP cells was much higher than that in CNE1 cells. These results suggested that MTA1 may play a critical role in promoting CDDP resistance in NPC cells by regulatingcancer stem cell properties via thePI3K/Akt signaling pathway. Our findings suggested that MTA1 may be a potential target for overcoming CDDP resistance in NPC therapy.

IUGR in rats is associated with changes in placental expression of MTAs

IUGR in rats is associated with changes in placental expression of MTAs

A chromatin modifier regulates Sertoli cell response to mono-(2-ethylhexyl) phthalate (MEHP) via tissue inhibitor of metalloproteinase 2 (TIMP2) signaling

Epigenetic silencing mechanisms are essential for regulating germ cell apoptosis in response to different stimuli during complicated spermatogenesis. Herein, we report the potential signaling events related to up-regulation of metastasis associated protein 1 (Mta1), a master chromatin modifier, during mono-(2-ethylhexyl) phthalate (MEHP)-induced Sertoli cells (SCs) injury. Mta1 up-regulation correlated to the gradual increases of MYC expression in MEHP-treated SCs. Selective knockdown of MYC abolished MEHP-induced activation of Mta1, suggesting that MYC may regulate the Mta1 signaling following MEHP injury. Furthermore, MTA1 acted as a specific corepressor of tissue inhibitor of metalloproteinase 2 (Timp2) during SCs injury. Mta1 repressed Timp2 expression either directly by recruiting histone deacetylase 2 onto the Timp2 promoter or indirectly by enhancing NF-κB-mediated inflammatory responses during MEHP injury. This transcriptional and post-translational down-regulation of Timp2/TIMP2 expression consequently resulted in the stimulated activation of matrix metalloproteinase 2 (MMP2) in SCs, which should ultimately promote germ cell death upon MEHP insult. From a functional standpoint, inhibition of endogenous Mta1 expression along with anti-inflammation treatment in cultured SCs could rescue MEHP-inhibited TIMP2 and subsequently rebalanced MMP2 activity to the control level. Together with the recently reported essential role of TIMP2/MMP2 signaling in MEHP-induced specific disruption of junctional complexes in the seminiferous epithelium, our results further substantiate a critical role of Mta1 in the control of SCs response to MEHP stimulation. The MYC/Mta1/TIMP2 circuit may serve as an important scavenger mechanism to help to maintain the capacity of damaged SCs to support germ cell development following MEHP injury.

Impact of histone deacetylase 1 and metastasis-associated gene 1 expression in esophageal carcinogenesis.

Animal models are important for the development of novel therapies for esophageal cancer. Histone deacetylase 1 (HDAC1)/metastasis-associated gene (MTA1) complexes inhibit p53 acetylation and thus, inhibit p53-induced apoptosis. The aim of the present study was to evaluate HDAC1 and MTA1 expression in esophageal carcinogenesis in rats. The rats underwent a total gastrectomy followed by esophagojejunostomy to induce chronic duodenal content reflux esophagitis. The rats were sacrificed sequentially at 20, 30, 40 and 50 weeks post-surgery and the esophagi were examined. Immunohistochemical analysis was conducted to assess the expression and localization of HDAC1 and MTA1. At 20 weeks post-surgery, squamous proliferative hyperplasia and Barrett’s metaplasia (BM) were observed. While, adenocarcinoma-associated BM and squamous cell carcinoma were observed at 30–50 weeks post-surgery. The nuclear expression of HDAC1 and MTA1 was observed in all of the stages of squamous carcinogenesis and adenocarcinogenesis, although not in the normal esophageal epithelium. The expression of HDAC1 and MTA1 may be involved in duodenoesophageal reflux-induced neoplastic transformation of the esophageal mucosa into cancer cells with squamous and adeno differentiation.

Estrogen Regulates the Tumour Suppressor MiRNA-30c and Its Target Gene, MTA-1, in Endometrial Cancer

MicroRNA-30c (miR-30c) has been reported to be a tumour suppressor in endometrial cancer (EC). We demonstrate that miR-30c is down-regulated in EC tissue and is highly expressed in estrogen receptor (ER)-negative HEC-1-B cells. MiR-30c directly inhibits MTA-1 expression and functions as a tumour suppressor via the miR-30c-MTA-1 signalling pathway. Furthermore, miR-30c is decreased upon E2 treatment in both ER-positive Ishikawa and ER-negative HEC-1-B cells. Taken together, our results suggest that miR-30c is an important deregulated miRNA in EC and might serve as a potential biomarker and novel therapeutic target for EC.

Elicitation of metastasis associated protein 2 expression in the phagocytosis by murine testicular Sertoli cells

Efficient phagocytic clearance of apoptotic spermatogenic cells and residual bodies (RBs) by Sertoli cells (SCs) is crucial for functional mature spermatogenesis. However, little is known about the molecular mechanisms underlying this SCs function. Herein, we reported for the first time that SCs-expressing metastasis associated protein 2 (Mta2), a chromatin modifier playing a critical role in modifying DNA accessibility for transcriptional regulation, was steadily up-regulated when SCs were co-cultured with RBs. The most efficient stimulatory substrates for the inducement of phagocytosis-elicited Mta2 expression were RBs and fragments from apoptotic spermatocytes. Furthermore, one major result of this response is the transcriptional repression of follicle-stimulating hormone receptor gene (Fshr) expression during phagocytosis, which should lead to a low level of circulated FSH because effects of FSH on spermatogenesis is fundamentally regulated by the down-regulation of Fshr after exposure to FSH. Given that high concentration of circulated FSH inhibits SCs phagocytic activity and impairment of MTA2 expression is associated with the abnormal high level of serum FSH, our present results suggest that the FSH/MTA2/Fshr cascade may serve as an indispensable negative feedback mechanism to help to maintain low level of circulated FSH, which is required for the normal occurrence of SCs phagocytosis.

Crosstalk between VEGF and MTA1 signaling pathways contribute to aggressiveness of breast carcinoma

The expression of metastasis associated protein (MTA1) correlates well with tumor metastasis; however its role as a proangiogenic protein and the molecular mechanisms underlying the same are not fully understood. In this study the MTA1 protein was expressed and purified to evaluate its angiogenic potential. In both MCF-7 and MDA-MB-231 cells, endogenous MTA1 protein was localized in the nucleus; while added recombinant MTA1 protein was bound to cell membrane as per immunofluorescence data. MTA1 was detected both in conditioned media and in human serum samples. Recombinant MTA1 regulated cellular functions of HUVEC's such as, proliferation, tube formation, and migration. MTA1 was more potent than VEGF in inducing invasion of breast cancer cells. Analogous to VEGF, MTA1 could induce angiogenesis in both non-tumor and tumor context, as verified by rat cornea, shell less CAM and xenograft models respectively. However MTA-1 was more potent an inducer of angiogenesis. VEGF or Flt-1 gene promoter, luciferase gene reporter analysis revealed that MTA1 up regulates the expression of VEGF and its receptor Flt-1 genes. Kinetics of VEGF-induced expression of MTA1 and qPCR studies showed that there is an increased expression of MTA1 in tumor cells. VEGF induced phosphorylation of endogenous MTA1 on tyrosine residues; phosphorylation was mediated through VEGFR2 and p38-MAP kinase. Recombinant MTA1 activated signaling, in MCF-7 and MDA-MB-231 cells, involved ERK and JNK pathways. In conclusion, MTA1 is a potent angiogenic molecule and cross talk between VEGF and MTA1 protein regulates tumor angiogenesis and metastasis.

Overexpression of MTA1 promotes invasiveness and metastasis of ovarian cancer cells

To investigate the effect of metastasis-associated gene MTA1 on proliferation and invasion potential of ovarian cancer cell line A2780. The eukaryotic expressing vector pcDNA3. 1-MTA1 was introduced into A2780 cells by gene transfection in vitro. The MTA1 mRNA and protein level in cancer cells were detected by reverse transcription polymerase chain reaction (RT-PCR) and western blot, respectively. The growth activities of cancer cells were detected by trypan blue stain method. The clone formation assay in soft agar was used to observe the proliferation of cancer cells. Wound healing assay and Transwell assay were used to evaluate migration and invasion abilities of cancer cells. And the protein level of bcl-xL in ovarian cancer cells was measured by immunohistochemistry and western blot. The TUNEL assay was performed to study the apoptosis of tumor cells. Seventy-two hours after transfection, the MTA1 expression increased significantly (P<0.01). The up-regulation of MTA1 did not affect the growth activities of cancer cells (P>0.05), but it promoted clone formation, migration and invasion abilities of cancer cells (P<0.01). The cellular expression of bcl-xL increased 65.22%, with a PI value of (71.64±5.96)%. With the up-regulation of MTA1 and bcl-xL level, the apoptotic rate of A2780 cell was decreased. MTA1 gene plays an important role in progression and metastasis of ovarian cancers, which provides an ideal strategy for gene therapy of ovarian cancers.

Metastasis tumor-associated protein 2 enhances metastatic behavior and is associated with poor outcomes in estrogen receptor-negative breast cancer

Metastasis remains a major clinical problem in breast cancer. One family of genes previously linked with metastasis is the metastasis tumor-associated (MTA) family, with members MTA1 enhancing and MTA3 inhibiting cancer metastasis. We have previously found that MTA2 enhances anchorage-independent growth in estrogen receptor α (ERα) breast cancers, and, in combination with other genes, performed as a predictive biomarker in ERα-positive breast cancer. We therefore hypothesized that MTA2 enhances breast cancer progression. To test this, cell growth, soft-agar colony formation, migration, and in vivo metastasis were examined in MTA2-overexpressing and Vector control transfected ERα-negative breast cancer cells. Pathways regulating cell-cell interaction, adhesion, and signaling through the Rho pathway were also investigated. Effects of the inhibition of the Rho pathway using a Rho Kinase inhibitor were assessed in soft-agar colony formation and motility assays in MTA2-overexpressing cells. MTA2 expression was associated with poor prognostic markers, and levels of MTA2 were associated with increased risk of early recurrence in retrospective analyses. MTA2 overexpression was associated with enhanced metastasis, and pathways regulating cell-cell interactions in vitro and in vivo. Most critically, MTA2-enhanced motility could be blocked by inhibiting Rho pathway signaling. We present the novel finding that MTA2 defined a subset of ERα-negative patients with a particularly poor outcome.

Overexpression of MTA3 Correlates with Tumor Progression in Non-Small Cell Lung Cancer

The objective of the current study was to investigate the expression pattern and clinicopathological significance of MTA3 in patients with non-small cell lung cancer (NSCLC). The expression profile of MTA3 in NSCLC tissues and adjacent noncancerous lung tissues was detected by immunohistochemistry. MTA3 was overexpressed in 62 of 108 (57.4%) human lung cancer samples and correlated with p-TNM stage (p<0.0001), nodal metastasis (p = 0.0009) and poor prognosis (p<0.05). In addition, the depletion of MTA3 expression with small interfering RNAs inhibited cell growth and colony formation in the A549 and H157 lung cancer cell lines. Moreover, MTA3 depletion induced cell cycle arrest at the G1/S boundary. Western blotting analysis revealed that the knockdown of MTA3 decreased the protein levels of cyclin A, cyclin D1 and p-Rb. These results indicate that MTA3 plays an important role in NSCLC progression.

P-0034 - Expression and Clinical Significance of Cd9 and Mta1 in Gastrointestinal Stromal Tumor

P-0034 - Expression and Clinical Significance of Cd9 and Mta1 in Gastrointestinal Stromal Tumor

The Metastasis-Associated Gene MTA3, a Component of the Mi-2/NuRD Transcriptional Repression Complex, Predicts Prognosis of Gastroesophageal Junction Adenocarcinoma

Gastroesophageal junction (GEJ) adenocarcinoma carries a poor prognosis that is largely attributable to early and frequent metastasis. The acquisition of metastatic potential in cancer involves epithelial-to-mesenchymal transition (EMT). The metastasis-associated gene MTA3, a novel component of the Mi-2/NuRD transcriptional repression complex, was identified as master regulator of EMT through inhibition of Snail to increase E-cadherin expression in breast cancer. Here, we evaluated the expression pattern of the components of MTA3 pathway and the corresponding prognostic significance in GEJ adenocarcinoma. MTA3 expression was decreased at both protein and mRNA levels in tumor tissues compared to the non-tumorous and lowed MTA3 levels were noted in tumor cell lines with stronger metastatic potential. Immunohistochemical analysis of a cohort of 128 cases exhibited that patients with lower expression of MTA3 had poorer outcomes. Combined misexpression of MTA3, Snail and E-cadherin had stronger correlation with malignant properties. Collectively, results suggest that the MTA3-regulated EMT pathway is altered to favor EMT and, therefore, disease progression and that MTA3 expression was an independent prognostic factor in patients with GEJ adenocarcinoma.

Abstract 4: Nuclear MTA1 overexpression is associated with aggressive prostate cancer and metastasis in African American men.

Abstract Metastasis-associate protein 1 (MTA1) plays essential role in prostate cancer (PCa) progression and metastasis. We hypothesized that nuclear MTA1 overexpression in primary tumor tissues may provide meaningful information on prediction of poor prognosis, i.e. MTA1 may serve as a prognostic biomarker for aggressive PCa and a predictor of recurrent disease and metastasis. We used tissue microarrays and clinicopathological information of 301 patients (146 Caucasian Americans and 155 African Americans) who underwent prostatectomy in University of Mississippi Medical Center, Jackson, MS and in University of Iowa, Iowa City, IA. We evaluated MTA1 expression by immunohistochemistry with the emphasis on subcellular localization and total staining score, which accounted intensity and frequency. MTA1 was detected in both cytoplasm and nucleus, however exhibited different expression patterns in terms of subcellular localization depending on pathological category of PCa and metastasis. A significant statistical correlation (p=0.063) was observed between MTA1 nuclear staining and localized PCa compared to PIN, reaching more significance with the worst grade (Gleason &amp;gt;7) and metastatic lesions (p&amp;lt;0.006). When analyzed in terms of racial differences, the difference in MTA1 nuclear overexpression between patients with localized PCa was highly significant (p&amp;lt;0.001), with Caucasian Americans showing higher levels of MTA1. However, when stratified by Gleason score, there were substantial differences in MTA1 levels in low grade tumors (Gleason ≤ 7) compared to high grade tumors (Gleason&amp;gt;7) in African Americans and not in Caucasians, indicating that MTA1 may serve as an “ethnic” biomarker for aggressive disease in African Americans. Moreover, there was a tendency for higher MTA1 nuclear staining in recurrent compared to non-recurrent group (n=50), particularly in African Americans (2.3 times difference). In summary, our observation might have clinical relevance in discriminating subset of low grade Gleason≤7 African American patients with low MTA1 expression who will remain recurrent-free from the same subset that have high MTA1 levels indicating possibility to develop more aggressive disease and metastasis. Putting together results of the current study and our previous finding that MTA1 is downregulated by dietary stilbenes we emphasize new perspectives for PCa management in African American men. Citation Format: Steven J. Dias, Xinchaun Zhou, Marina Ivanovic, Michael P. Gailey, Swati Dhar, Zhi He, Alan Penman, Anait S. Levenson. Nuclear MTA1 overexpression is associated with aggressive prostate cancer and metastasis in African American men. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4. doi:10.1158/1538-7445.AM2013-4

Abstract 5551: Role of YB-1, a regulator of epithelial to mesenchymal transition, in prostate cancer: inhibition by a dietary flavonoid fisetin.

Abstract The most common signature of aggressive cancers such as prostate cancer (PCa) involves metastasis. Tumor cell migration is a key step for formation of cancer metastasis and recent data suggest that mammalian target of rapamycin (mTOR) controls the metastatic landscape of PCa by regulating the expression of genes known to be involved in PCa metastasis. Also, current estimates suggest that PI3K/Akt/mTOR signaling is upregulated in 30-50% of PCa patients. We observed that the expression of a set of four signature genes YB-1, MTA1, CD-44 and vimentin, regulated by mTOR and known to be involved in metastasis, is significantly higher in PCa PC-3 and DU145 cells compared to normal prostate epithelial cells. siRNA mediated knockdown of YB-1 in both PC-3 and DU-145 cells resulted in inhibition of EMT as seen by a significant decrease in mesenchymal morphology associated with induction of E-cadherin and inhibition of YB-1. We recently showed that fisetin, a dietary flavonoid, is also a specific inhibitor of the mTOR pathway. We hypothesized that fisetin will inhibit epithelial to mesenchymal transition (EMT) in PCa cells by binding to and inhibiting the YB-1. Using in silico docking studies, we observed that fisetin interacts with the cold shock domain (CSD) of the YB-1 molecule. Fisetin binds to YB-1 protein located on residues from β1 and β4 strands of the CSD and shows consistent binding modes and tight affinity within the amino acid pocket. Calculated free binding energy for these conformations ranged from -11.9845 to -9.6273 kcal/mol suggesting strong binding affinity. Treatment of PCa PC-3 and DU145 cells with fisetin (0-80 μM) resulted in inhibition of cell motility that was associated with inhibition of phosphorylation of mTOR at Ser2481 and Ser2448 and YB-1. Using immuno-fluorescence we found that fisetin treatment induced E-cadherin re-expression and inhibited vimentin expression in both DU-145 and PC-3 cells suggesting a reversal of the EMT. This reversal of EMT phenotype was also associated with induction of occludin and claudin-1 and inhibition of fibronectin, N-cadherin, MTA1 and CD-44 expression. We also observed that fisetin treatment inhibited nuclear expression of repressors of EMT such as Snail, Slug and Twist. Because tumor cell migration is a key step for formation of cancer metastasis, we determined the effect of fisetin on cell migration using PC-3 cells. Fisetin treatment inhibited cell migration at both 40 and 80 μM that was associated with decrease in the expression of MMP2 and MMP9. In summary, we observed that YB-1 expression induces EMT in PCa cells and identified fisetin as a novel agent that binds to it and potentially interferes with its activity. Based on our observations we suggest that fisetin could be developed as a clinically relevant inhibitor of mTOR/YB-1 with therapeutic benefit for PCa metastasis and invasion. Citation Format: Vaqar Mustafa Adhami, Mohammad Imran Khan, Rahul K. Lall, Imtiaz A. Siddiqui, Deeba N. Syed, Mario Sechi, Shah-Jahan M. Dodwad, Hasan Mukhtar. Role of YB-1, a regulator of epithelial to mesenchymal transition, in prostate cancer: inhibition by a dietary flavonoid fisetin. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 5551. doi:10.1158/1538-7445.AM2013-5551

MTA2 expression is a novel prognostic marker for pancreatic ductal adenocarcinoma

The aim of this study was to detect MTA2 expression in pancreatic ductal adenocarcinoma (PDA) and to analyze its association with prognosis of PDA patients. MTA2 mRNA and protein expression were determined by real-time quantitative reverse transcriptase-polymerase chain reaction and immunohistochemistry in specimens of primary cancer and their adjacent noncancerous tissues in PDA patients. We found that MTA2 mRNA and protein expression levels were both significantly upregulated in PDA lesions compared with adjacent noncancerous tissues. Immunohistochemistry showed that high MTA2 expression was correlated with poor tumor differentiation, TNM stage, and lymph node metastasis. Kaplan-Meier survival analysis showed that patients with high expression levels of MTA2 showed lower overall survival rate than those with low expression levels. Multivariate analysis showed that high MTA2 protein expression was an independent prognostic factor for PDA patients. Our study suggests that overexpression of MTA2 may play an important role in the progression of PDA and MTA2 expression may serve as a biomarker for poor prognosis for PDA.