Phosphorylation hotspot in the C-terminal domain of occludin regulates the dynamics of epithelial junctional complexes

The apical junctional complex (AJC), which includes tight junctions (TJs) and adherens junctions (AJs), determines the epithelial polarity, cell-cell adhesion and permeability barrier. An intriguing characteristic of a TJ is the dynamic nature of its multiprotein complex. Occludin is the most mobile TJ protein, but its significance in TJ dynamics is poorly understood. On the basis of phosphorylation sites, we distinguished a sequence in the C-terminal domain of occludin as a regulatory motif (ORM). Deletion of ORM and expression of a deletion mutant of occludin in renal and intestinal epithelia reduced the mobility of occludin at the TJs. ORM deletion attenuated Ca2+ depletion, osmotic stress and hydrogen peroxide-induced disruption of TJs, AJs and the cytoskeleton. The double point mutations T403A/T404A, but not T403D/T404D, in occludin mimicked the effects of ORM deletion on occludin mobility and AJC disruption by Ca2+ depletion. Both Y398A/Y402A and Y398D/Y402D double point mutations partially blocked AJC disruption. Expression of a deletion mutant of occludin attenuated collective cell migration in the renal and intestinal epithelia. Overall, this study reveals the role of ORM and its phosphorylation in occludin mobility, AJC dynamics and epithelial cell migration.

Abstract 5252: Quercetin inhibits prostate cancer by modulating ROS and key regulators of apoptosis and cell survival

Long latency and indolent nature of prostate cancer (PCa) provides a window of opportunity for preventive interventions using natural and synthetic agents. Hence, the focus of this study was to ascertain the chemopreventive role of Quercetin, a bioflavonoid, commonly used to treat prostatitis. Human PCa cells (LNCaP, DU145 and PC3) were treated with different concentrations of Quercetin and its effect on cell survival and apoptosis was determined by MTT assay. Human PCa cells treated with Quercetin showed significant reduction in cell viability and proliferation compared with untreated controls, which was dose and time dependent. In addition to this our FACS analysis showed higher percentage of apoptotic cells after Quercetin treatment compared to untreated cells. Quercetin induced apoptosis in PCa cells is a cumulative effect of modulation of key apoptotic proteins, changes in mitochondrial membrane potential and ROS production. Our results demonstrate that Quercetin is a potent chemopreventive agent, which may improve outcomes of PCa by inhibiting mechanisms involved in tumor progression.

Citation Format: Ashley B. Ward, Hina Mir, Neeraj Kapur, Guru Sonpavde, Shailesh Singh. Quercetin inhibits prostate cancer by modulating ROS and key regulators of apoptosis and cell survival [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 5252. doi:10.1158/1538-7445.AM2017-5252

Abstract 2328: Race specific hyper-activation of CCR9-mediated survival signals and its impact on efficacy of docetaxel in prostate cancer

Current approaches to treat and manage prostate cancer (PCa) have failed to reduce racial disparity primarily due to undefined molecular mechanism. We have shown higher expression of chemokine receptor-9 in PCa cells and CCR9 expression was higher in PCa cells (MDA-PCa-2b) derived from African American (AA) patient compared to PCa cells derived form European American (EA) patients (LNCaP and PC3). Using antibody microarray we observed hyper activation of survival molecules and down-regulation of apoptotic molecules in AA PCa cells compared to EA PCa cell lines, following CCL25 stimulation. Comparative heat map analysis showed significant increase (~2-3 fold) in phosphorylation of pro-survival proteins in AA cells compared to EA cells treated with CCL25, which was further confirmed by western blot analysis. Furthermore, CCL25 treated PCa cells showed decreased expression of pro-apoptotic proteins (Bim, Bid, Bak), which was significantly abrogated by CCR9 shRNA. This effect was more pronounced in AA cells compared to EA cells. Efficacy of docetaxel (DTX) was higher after CCR9 blockade in presence of CCL25 compared to cells treated with CCL25 without blocking CCR9. Improvement in efficacy of DTX was due to inhibition of cell survival and activation of pro-apoptotic signals following CCR9 blockade. These observations suggest potential involvement of CCR9 mediated molecular pathways in disparity associated with outcome of PCa.

Citation Format: Neeraj Kapur, Hina Mir, Guru Sonpavde, Shailesh Singh. Race specific hyper-activation of CCR9-mediated survival signals and its impact on efficacy of docetaxel 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 2328. doi:10.1158/1538-7445.AM2017-2328

Abstract 1263: Andrographolide inhibits prostate cancer by suppressing cytokine involved in promoting epithelial to mesenchymal transition

Mesenchymal phenotypes are responsible for cancer progression and poor therapeutic response. Hence, approaches targeting mesenchymal phenotype or inhibiting epithelial to mesenchymal transition will significantly prevent cancer progression or improve therapeutic outcome. Using in vitro models and molecular approaches we have shown that Andrographolide (AG), a compound isolated from Andrographis paniculata, shows promising effect on mesenchymal cells. It disposes PCa cells towards epithelial phenotype by modulating E-cadherin, ZEB-1, SNAIL and TWIST. In addition to these, significant inhibition in IL-6, which is known to be a poor prognostic maker, was observed in PCa cells treated with AG compared to untreated cells. This reduction in IL-6 could be due to AG induced suppression of SOCS (Suppressor of cytokine signaling) molecules. Therefore, our data underscores the ability of AG to impede cancer growth by impacting EMT and rationalizes its application as a potent therapeutic agent.

Citation Format: Hina Mir, Neeraj Kapur, Guru Sonpavde, Shailesh Singh. Andrographolide inhibits prostate cancer by suppressing cytokine involved in promoting epithelial to mesenchymal transition [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 1263. doi:10.1158/1538-7445.AM2017-1263

Andrographolide inhibits prostate cancer by targeting cell cycle regulators, CXCR3 and CXCR7 chemokine receptors

Despite state of the art cancer diagnostics and therapies offered in clinic, prostate cancer (PCa) remains the second leading cause of cancer-related deaths. Hence, more robust therapeutic/preventive regimes are required to combat this lethal disease. In the current study, we have tested the efficacy of Andrographolide (AG), a bioactive diterpenoid isolated from Andrographis paniculata, against PCa. This natural agent selectively affects PCa cell viability in a dose and time-dependent manner, without affecting primary prostate epithelial cells. Furthermore, AG showed differential effect on cell cycle phases in LNCaP, C4-2b and PC3 cells compared to retinoblastoma protein (RB(-/-)) and CDKN2A lacking DU-145 cells. G2/M transition was blocked in LNCaP, C4-2b and PC3 after AG treatment whereas DU-145 cells failed to transit G1/S phase. This difference was primarily due to differential activation of cell cycle regulators in these cell lines. Levels of cyclin A2 after AG treatment increased in all PCa cells line. Cyclin B1 levels increased in LNCaP and PC3, decreased in C4-2b and showed no difference in DU-145 cells after AG treatment. AG decreased cyclin E2 levels only in PC3 and DU-145 cells. It also altered Rb, H3, Wee1 and CDC2 phosphorylation in PCa cells. Intriguingly, AG reduced cell viability and the ability of PCa cells to migrate via modulating CXCL11 and CXCR3 and CXCR7 expression. The significant impact of AG on cellular and molecular processes involved in PCa progression suggests its potential use as a therapeutic and/or preventive agent for PCa.

Abstract 1701: CCR6 associates with colon cancer metastasis

Despite established benefits of screening, colon cancer remains a leading cause of cancer death in the U.S. Majority of colon cancer deaths result from metastasis. Effective treatments are not available for advanced disease because molecular mechanisms of initiation and progression of this disease are yet to be defined. Chemokine-chemokine receptor interaction plays an important role in cancer progression. In this study, using colon cancer tissue microarray, we have shown that expression of CCR6 was significantly higher in advanced colon cancer (p<0.0001) with distant and regional lymph node metastasis as compared to non-metastatic and adjacent normal tissues. Expression of CCR6 was further confirmed in cell lines derived from Dukes's type C and type D colon cancer patients using flow cytometric analysis. Like tissues, CCR6 expression was significantly (p<0.0001) higher in colon cancer cell lines compared to normal colon epithelial cells. Furthermore, colon cancer cells showed higher migratory potential toward chemotactic gradient of its only known natural ligand, CCL20. Cell proliferation was also inhibited in presence of CCL20. Significant decrease in E-cadherin, increased expression of vimentin, β-catenin, N-cadherin, α-SMA, SNAIL and ZEB1 was observed following CCL20 treatment. These results suggest the importance of CCR6-CCL20 axis in the etiopathogenesis of colon cancer and highlight its potential as therapeutic target.

Citation Format: Neeraj Kapur, Hina Mir, Clarence E. Clark, Uma Krishnamurti, Derrick J. Beech, James W. Lillard, Shailesh Singh. CCR6 associates with colon cancer metastasis. [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 1701.

Abstract 5254: Andrographolide prevents prostate cancer by targeting CXCR3/CXCR7 and regulators of cell cycle

Despite state of the art cancer diagnostics and therapies offered in clinics, prostate cancer (PCa) remains the second leading cause of cancer-related deaths in men. Hence, more robust therapeutic/preventive regimes are required to combat this lethal disease. In the current study, we have tested the efficacy of andrographolide (AG), a bioactive diterpenoid isolated from Andrographis paniculata, against PCa. This natural agent selectively affects PCa cell viability in a dose and time-dependent manner, without affecting primary prostate epithelial cells. Furthermore, AG showed differential effect on phases of cell cycle in LNCaP, C4-2b and PC3 cell lines compared to retinoblastoma protein (RB-/-) lacking DU-145 cells. This agent blocked the G2/M transition in LNCaP, C4-2b and PC3 whereas DU-145 cells failed to transit G1/S phase. This difference was primarily due to switching of the activation states of cell cycle regulators in these cell lines. AG induced its effect mainly via cyclin A2 and B1 in LNCaP, C4-2b and PC3 cell lines; whereas, cyclin E related regulation was affected in DU-145 cells. Phosphorylation status of Wee1, a nuclear kinase belonging to the Ser/Thr family and CDC2 was also affected by AG. Intriguingly, AG affected cell viability and the ability of PCa cells to migrate via modulating CXCL11 and CXCR3 and CXCR7 expression. The significant impact of AG on cellular and molecular processes involved in PCa progression suggest this agent has potential to be used as a therapeutic and/or preventive modality.

Citation Format: Hina Mir, Neeraj Kapur, Rajesh Singh, Guru Sonpavde, James W. Lillard, Shailesh Singh. Andrographolide prevents prostate cancer by targeting CXCR3/CXCR7 and regulators of cell cycle. [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 5254.

Chronic ethanol feeding promotes azoxymethane and dextran sulfate sodium-induced colonic tumorigenesis potentially by enhancing mucosal inflammation

Background

Alcohol consumption is one of the major risk factors for colorectal cancer. However, the mechanism involved in this effect of alcohol is unknown.

Methods

We evaluated the effect of chronic ethanol feeding on azoxymethane and dextran sulfate sodium (AOM/DSS)-induced carcinogenesis in mouse colon. Inflammation in colonic mucosa was assessed at a precancerous stage by evaluating mucosal infiltration of neutrophils and macrophages, and analysis of cytokine and chemokine gene expression.

Results

Chronic ethanol feeding significantly increased the number and size of polyps in colon of AOM/DSS treated mice. Confocal microscopic and immunoblot analyses showed a significant elevation of phospho-Smad, VEGF and HIF1α in the colonic mucosa. RT-PCR analysis at a precancerous stage indicated that ethanol significantly increases the expression of cytokines IL-1α, IL-6 and TNFα, and the chemokines CCL5/RANTES, CXCL9/MIG and CXCL10/IP-10 in the colonic mucosa of AOM/DSS treated mice. Confocal microscopy showed that ethanol feeding induces a dramatic elevation of myeloperoxidase, Gr1 and CD68-positive cells in the colonic mucosa of AOM/DSS-treated mice. Ethanol feeding enhanced AOM/DSS-induced suppression of tight junction protein expression and elevated cell proliferation marker, Ki-67 in the colonic epithelium.

Conclusion

This study demonstrates that chronic ethanol feeding promotes colonic tumorigenesis potentially by enhancing inflammation and elevation of proinflammatory cytokines and chemokines.

Occludin deficiency promotes ethanol-induced disruption of colonic epithelial junctions, gut barrier dysfunction and liver damage in mice

BACKGROUND

Disruption of epithelial tight junctions (TJ), gut barrier dysfunction and endotoxemia play crucial role in the pathogenesis of alcoholic tissue injury. Occludin, a transmembrane protein of TJ, is depleted in colon by alcohol. However, it is unknown whether occludin depletion influences alcoholic gut and liver injury.

METHODS

Wild type (WT) and occludin deficient (Ocln(-/-)) mice were fed 1-6% ethanol in Lieber-DeCarli diet. Gut permeability was measured by vascular-to-luminal flux of FITC-inulin. Junctional integrity was analyzed by confocal microscopy. Liver injury was assessed by plasma transaminase, histopathology and triglyceride analyses. The effect of occludin depletion on acetaldehyde-induced TJ disruption was confirmed in Caco-2 cell monolayers.

RESULTS

Ethanol feeding significantly reduced body weight gain in Ocln(-/-) mice. Ethanol increased inulin permeability in colon of both WT and Ocln(-/-) mice, but the effect was 4-fold higher in Ocln(-/-) mice. The gross morphology of colonic mucosa was unaltered, but ethanol disrupted the actin cytoskeleton, induced redistribution of occludin, ZO-1, E-cadherin and β-catenin from the junctions and elevated TLR4, which was more severe in Ocln(-/-) mice. Occludin knockdown significantly enhanced acetaldehyde-induced TJ disruption and barrier dysfunction in Caco-2 cell monolayers. Ethanol significantly increased liver weight and plasma transaminase activity in Ocln(-/-) mice, but not in WT mice. Histological analysis indicated more severe lesions and fat deposition in the liver of ethanol-fed Ocln(-/-) mice. Ethanol-induced elevation of liver triglyceride was also higher in Ocln(-/-) mice.

CONCLUSION

This study indicates that occludin deficiency increases susceptibility to ethanol-induced colonic mucosal barrier dysfunction and liver damage in mice.

Performance of rapid influenza diagnostic tests (QuickVue) for influenza A and B Infection in India

BACKGROUND

Rapid point-of-care (POC) tests provide an economical alternative for rapid diagnosis and treatment of influenza, especially in public health emergency situations.

OBJECTIVES

To test the performance of a rapid influenza diagnostic test, QuickVue (Quidel) as a POC test against a real-time polymerase chain reaction (RT-PCR) assay for detection of influenza A and B in a developing country setting.

STUDY DESIGN

In a prospective observational design, 600 patients with influenza-like illness (ILI) or with severe acute respiratory illness (SARI) who were referred to the Influenza Clinic of a tertiary care hospital in Srinagar, India from September 2012 to April 2013, were enrolled for diagnostic testing for influenza using QuickVue or RT-PCR. All influenza A-positive patients by RT-PCR were further subtyped using primers and probes for A/H1pdm09 and A/H3.

RESULTS

Of the 600 patients, 186 tested positive for influenza A or B by RT-PCR (90 A/H1N1pdm09, 7 A/H3 and 89 influenza B), whereas only 43 tested positive for influenza (influenza A=22 and influenza B=21) by QuickVue. Thus, the sensitivity of the QuickVue was only 23% (95% confidence interval, CI: 17.3-29.8) and specificity was 100% (95% CI: 99.1-100) with a positive predictive value (PPV) of 100% (95% CI 91.8-100) and a negative predictive value (NPV) of 74.3% (95% CI: 70.5-77.9) as compared to RT-PCR.

CONCLUSIONS

The high specificity of QuickVue suggest that this POC test can be a useful tool for patient management or triaging during a public health crisis but a low sensitivity suggests that a negative test result need to be further tested using RT-PCR.

Glutamine supplementation attenuates ethanol-induced disruption of apical junctional complexes in colonic epithelium and ameliorates gut barrier dysfunction and fatty liver in mice

Previous in vitro studies showed that glutamine (Gln) prevents acetaldehyde-induced disruption of tight junctions and adherens junctions in Caco-2 cell monolayers and human colonic mucosa. In the present study, we evaluated the effect of Gln supplementation on ethanol-induced gut barrier dysfunction and liver injury in mice in vivo. Ethanol feeding caused a significant increase in inulin permeability in distal colon. Elevated permeability was associated with a redistribution of tight junction and adherens junction proteins and depletion of detergent-insoluble fractions of these proteins, suggesting that ethanol disrupts apical junctional complexes in colonic epithelium and increases paracellular permeability. Ethanol-induced increase in colonic mucosal permeability and disruption of junctional complexes were most severe in mice fed Gln-free diet. Gln supplementation attenuated ethanol-induced mucosal permeability and disruption of tight junctions and adherens junctions in a dose-dependent manner, indicating the potential role of Gln in nutritional intervention to alcoholic tissue injury. Gln supplementation dose-dependently elevated reduced-protein thiols in colon without affecting the level of oxidized-protein thiols. Ethanol feeding depleted reduced protein thiols and elevated oxidized protein thiols. Ethanol-induced protein thiol oxidation was most severe in mice fed with Gln-free diet and absent in mice fed with Gln-supplemented diet, suggesting that antioxidant effect is one of the likely mechanisms involved in Gln-mediated amelioration of ethanol-induced gut barrier dysfunction. Ethanol feeding elevated plasma transaminase and liver triglyceride, which was accompanied by histopathologic lesions in the liver; ethanol-induced liver damage was attenuated by Gln supplementation. These results indicate that Gln supplementation ameliorates alcohol-induced gut and liver injury.

CCR9/CCL25 expression in non-small cell lung cancer correlates with aggressive disease and mediates key steps of metastasis

Poor clinical outcome of lung cancer (LuCa) is primarily due to lack of knowledge about specific molecules involved in its progression and metastasis. In this study, we for the first time show the clinical and biological significance of CC chemokine receptor-9 (CCR9) in non-small cell lung cancer (NSCLC). Expression of CCR9 and CCL25, the only natural ligand of CCR9, was significantly higher (p < 0.0001) in NSCLC tissues and serum respectively, compared to their respective controls. Interestingly, expression of both CCR9 and CCL25 was significantly higher in adenocarcinomas (ACs) compared to squamous cell carcinomas (SCCs) (p = 0.04, and p < 0.0001). Similar to tissues, AC and SCC cell lines were positive for CCR9 expression. Despite of marginal difference in CCR9 expression, AC cells showed higher migratory and invasive potential in response to CCL25, compared to SCC cells. This differential biological response of AC cells was primarily due to differential expression of matrix metalloproteinases and tissue inhibitor of metalloproteinases under the influence of CCL25. Our results suggest CCR9 as a potential target for developing new treatment modality for NSCLC. Additionally, differential serum CCL25 level in ACs and SCCs, two NSCLC subtypes, suggest its potential as a non-invasive diagnostic/prognostic biomarker.

Abstract 3499: Improving therapeutic efficacy of Docetaxel in breast cancer

Chemotherapy is the preferred choice for treatment of advance breast cancer (BrCa). In most cases, cytotoxic drugs are used at or near a maximum tolerated dose (MTD) to achieve maximum response and eradicate the neoplastic cells, at the same time MTD doses are often toxic and have severe side effects. Lower dose i.e. “optimal biological response modifier dose” (OBRMD) provides potentially beneficial responses, but is not capable of achieving optimal clinical response. Hence, the focus of this study was to achieve the optimal therapeutic outcome of Docetaxel (DTX) at a lower dose by using it in combination with Apigenin (API), a dietary flavonoid present in fruits and vegetables. Effect of DTX and API, either alone or in combination on BrCa cells viability and apoptosis was determined by MTT assay and flow cytometry, respectively. We further investigated the mechanism of enhanced efficacy of DTX using western blot analysis and real time qPCR. Significant decrease in cell viability was observed when cells were treated with low dose DTX in combination with API as compared to either of the agent used individually in MDA-MB-231, MDA-MB-468 and MCF 10A cells. Real time analysis showed that API up regulates pro-apoptotic molecules and down regulates anti-apoptotic molecules when using in combination with DTX. These findings suggest that Apigenin is capable of reducing the effective dose of docetaxel. Hence, this new modality may have better therapeutic outcome with minimal or no toxicity.

Citation Format: Jeronay King, Hina Mir, Neeraj Kapur, Shailesh Singh. Improving therapeutic efficacy of Docetaxel in breast cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3499. doi:10.1158/1538-7445.AM2015-3499

Abstract 5190: CCR6-mediated molecular mechanisms involved in colon cancer

Colon cancer is one of the leading causes of death due to cancer worldwide. Molecular mechanism of initiation and progression of this disease is yet to be defined. Chemokines and their corresponding receptors have been shown to play important role in progression of many cancers including colon. In this study we have demonstrated that CCR6 is highly expressed in colon cancer and is associated with key steps of metastasis. Cell migration, adhesion and invasion are the key features of cancer progression. This process initiates with the change of less motile epithelial phenotype to a more motile mesenchymal type, the phenomenon known as epithelial-mesenchymal transition (EMT). Interestingly, stimulation of colon cancer cell with CCL20, which is the only natural ligand for CCR6, showed significant decrease in E-cadherin. Furthermore, increased Vimentin, beta-Catenin, N-cadherin, alpha-Smooth Muscle Actin (αSMA) and Snail following CCL20 treatment implicates potential role of CCR6-CCL20 axis in transition to mesenchymal phenotype. Hence, strategies directed to this chemokine-receptor axis may improve therapeutic outcome of colon cancer.

Citation Format: Neeraj Kapur, Hina Mir, Rajesh Singh, Shailesh Singh. CCR6-mediated molecular mechanisms involved in colon cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5190. doi:10.1158/1538-7445.AM2015-5190

Abstract 5362: Andrographolide inhibits prostate cancer by modulating chemokine and cytokines

Treatment options for androgen independent prostate cancer (PCa) are limited. Hence, new treatment strategies are needed to treat/prevent hormone refractory advance disease. Major focus of this study was to develop non-toxic therapeutic/preventive option for PCa. Andrographolide (AG), a bioactive diterpenoid isolated from Andrographis paniculata showed dose and time dependent inhibition of PCa cells (PC3, DU145 and LNCaP). This inhibition in growth was due to selective modulation of chemokines and cytokines required for PCa cell growth and proliferation. Specifically, CXCR3 and CXCR7 expression was reduced after AG treatment. Interestingly, AG inhibited IL-6 expression, which is known to be associated with advance PCa and also highly produced by the aggressive PCa cell compared to less aggressive or normal prostatic epithelial cells. Hence, AG may be offered as a new therapeutic/preventive agent against PCa due to its ability to inhibit key chemokines and cytokines required for PCa progression and supporting hormone refractory PCa.

Citation Format: Hina Mir, Neeraj Kapur, Rajesh Singh, Guru Sonpavde, James W. Lillard, Shailesh Singh. Andrographolide inhibits prostate cancer by modulating chemokine and cytokines. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5362. doi:10.1158/1538-7445.AM2015-5362

Abstract 4107: CCR9/CCL25 mediates epithelial-mesenchymal transition in prostate cancer

Prostate cancer (PCa) is the second leading cause of cancer-related deaths in men, despite the treatment options offered in the clinics. Hence, it is important to further elucidate the molecular mechanisms of PCa progression in order to design more effective treatment strategies. PCa metastasis is a multi-step process that involves epithelial-mesenchymal transition (EMT), during which stationary epithelial cancer cells adopt a mesenchymal phenotype that better suits for survival and motility. We have previously shown that CCR9-expressing PCa cells migrate to and invade distal secondary sites under the influence of chemokine CCL25, its natural ligand. However, the precise molecular mechanisms facilitating EMT in PCa are still not fully understood. Here, we investigated the biological significance of CCR9/CCL25 signaling in inducing EMT in PCa. Modulation of several EMT markers was assessed by western blot and real time qPCR in metastatic PCa cell lines, with or without CCL25 activation. Our results show that following CCL25 stimulation, CCR9 signaling differentially modulates expression of the EMT markers E-cadherin and N-Cadherin in PCa cells, as compared to untreated controls. These findings suggest that the CCR9-CCL25 axis plays an important role in mediating EMT in PCa, thereby increasing the ability of PCa cells to metastasize.

Citation Format: Patrick P. Carriere, Hina Mir, Neeraj Kapur, Rajesh Singh, Guru Sonpavde, James W. Lillard, Shailesh Singh. CCR9/CCL25 mediates epithelial-mesenchymal transition in prostate cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4107. doi:10.1158/1538-7445.AM2015-4107

ALDH2 Deficiency Promotes Ethanol-Induced Gut Barrier Dysfunction and Fatty Liver in Mice

BACKGROUND

Acetaldehyde, the toxic ethanol (EtOH) metabolite, disrupts intestinal epithelial barrier function. Aldehyde dehydrogenase (ALDH) detoxifies acetaldehyde into acetate. Subpopulations of Asians and Native Americans show polymorphism with loss-of-function mutations in ALDH2. We evaluated the effect of ALDH2 deficiency on EtOH-induced disruption of intestinal epithelial tight junctions and adherens junctions, gut barrier dysfunction, and liver injury.

METHODS

Wild-type and ALDH2-deficient mice were fed EtOH (1 to 6%) in Lieber-DeCarli diet for 4 weeks. Gut permeability in vivo was measured by plasma-to-luminal flux of FITC-inulin, tight junction and adherens junction integrity was analyzed by confocal microscopy, and liver injury was assessed by the analysis of plasma transaminase activity, histopathology, and liver triglyceride.

RESULTS

EtOH feeding elevated colonic mucosal acetaldehyde, which was significantly greater in ALDH2-deficient mice. ALDH2(-/-) mice showed a drastic reduction in the EtOH diet intake. Therefore, this study was continued only in wild-type and ALDH2(+/-) mice. EtOH feeding elevated mucosal inulin permeability in distal colon, but not in proximal colon, ileum, or jejunum of wild-type mice. In ALDH2(+/-) mice, EtOH-induced inulin permeability in distal colon was not only higher than that in wild-type mice, but inulin permeability was also elevated in the proximal colon, ileum, and jejunum. Greater inulin permeability in distal colon of ALDH2(+/-) mice was associated with a more severe redistribution of tight junction and adherens junction proteins from the intercellular junctions. In ALDH2(+/-) mice, but not in wild-type mice, EtOH feeding caused a loss of junctional distribution of tight junction and adherens junction proteins in the ileum. Histopathology, plasma transaminases, and liver triglyceride analyses showed that EtOH-induced liver damage was significantly greater in ALDH2(+/-) mice compared to wild-type mice.

CONCLUSIONS

These data demonstrate that ALDH2 deficiency enhances EtOH-induced disruption of intestinal epithelial tight junctions, barrier dysfunction, and liver damage.

Cognitive workload modulation through degraded visual stimuli: a single-trial EEG study

OBJECTIVE

Our experiments explored the effect of visual stimuli degradation on cognitive workload.

APPROACH

We investigated the subjective assessment, event-related potentials (ERPs) as well as electroencephalogram (EEG) as measures of cognitive workload.

MAIN RESULTS

These experiments confirm that degradation of visual stimuli increases cognitive workload as assessed by subjective NASA task load index and confirmed by the observed P300 amplitude attenuation. Furthermore, the single-trial multi-level classification using features extracted from ERPs and EEG is found to be promising. Specifically, the adopted single-trial oscillatory EEG/ERP detection method achieved an average accuracy of 85% for discriminating 4 workload levels. Additionally, we found from the spatial patterns obtained from EEG signals that the frontal parts carry information that can be used for differentiating workload levels.

SIGNIFICANCE

Our results show that visual stimuli can modulate cognitive workload, and the modulation can be measured by the single trial EEG/ERP detection method.

Response of Dictyostelium discoideum to UV-C and involvement of poly (ADP-ribose) polymerase

OBJECTIVES

Radiation and chemical mutagens are direct DNA-damaging agents and ultraviolet (UV) radiation is frequently used in biological studies. Consequent to ozone depletion, UV-C could become a great challenge to living organisms on earth, in the near future. The present study has focused on the role of poly (ADP-ribose) polymerase (PARP) during UV-C-induced growth and developmental changes in Dictyostelium discoideum, a phylogenetically important unicellular eukaryote.

MATERIALS AND METHODS

Dictyostelium discoideum cells were exposed to different doses of UV-C and PARP activity, and effects of its inhibition were studied. Expression of developmentally regulated genes yakA, car1, aca, csA, regA, ctnA, ctnB, gp24, hspD and dsn were analysed using semiquantitative RT-PCR.

RESULTS

We report that the D. discoideum cells displayed PARP activation within 2 min of UV-C irradiation and there was increase in NO levels in a dose-dependent manner. UV-C-irradiated cells had impaired growth, delayed or blocked development and delayed germination compared to control cells. In our previous studies we have shown that inhibition of PARP recovered oxidative stress-induced changes in D. discoideum; however, intriguingly PARP inhibition did not correct all defects as effectively in UV-C-irradiated cells. This possibly was due to interplay with increased NO signalling.

CONCLUSIONS

Our results signify that UV-C and oxidative stress affected growth and development in D. discoideum by different mechanisms; these studies could provide major clues to complex mechanisms of growth and development in higher organisms.