Abstract 4047: Potential role of CXCR6-CXCL16 in prostate cancer progression and chemotherapeutic efficacy

Despite recent advances in treatment and clinical management, prostate cancer is still a leading cause of cancer related deaths among men, primarily because etiopathogenesis of PCa is not well defined. In this regard, chemokines and their corresponding receptors have been shown to play major role in PCa progression, which are often associated with poor therapeutic outcomes. Hence, the focus of this study is to determine the potential role of CXCR6 and its natural ligand CXCL16 in PCa pathogenesis, and potential impact of CXCR6-CXCL16 axis on efficacy of docetaxel, which is currently offered in the clinics as standard care.

We investigated expression of CXCR6 and CXCL16 in clinical samples, prostate cancer cell lines and normal prostatic epithelial cells. Expression of CXCR6 and CXCL16 was significantly higher in PCa samples compared to their respective controls, and expression of CXCR6/ CXCL16 was correlated with tumor stage and grades. Similar to patient's samples, expression of CXCR6/CXCL16 was significantly higher in PCa cell lines compared to normal prostatic epithelial cells. Furthermore, levels of phospho -ERK1/2 and -NF-kB, known to be involved in cell growth and survival, were significantly higher in PCa cells treated with CXCL16 compared to untreated controls. In addition to these, role of CXCR6- CXCL16 on genes responsible for cellular adhesion and epithelial-mesenchymal transition were examined. Interestingly, expression of surface E-cadherin and β−catenin following CXCL16 treatment was significantly inhibited compared to untreated cells, suggesting the involvement of CXCR6-CXCL16 interaction in PCa cell migration. Additionally, CXCR6 expressing PCa cells expressed higher α−smooth muscle actin protein, another EMT marker presumably induced by elevated TGF-β, following CXCL16 stimulation. Furthermore, expression of CXCR6, CXCL16 and MMP(s) were elevated in PCa cell following docetaxel treatment in a time and dose dependent manner compared to controls. This may explain the increased efficacy of docetaxel when used in combination with anti-CXCR6 antibody as compared to docetaxel alone. These findings suggest that CXCR6-CXCL16 axis plays a crucial role in pathogenesis of PCa, and inhibition of this axis may have significant impact on disease progression and therapeutics outcomes.

Citation Format: Pranav Gupta, Ashley B. Ward, Hina Mir, Gurpreet Kaur, William E. Grizzle, James W. Lillard, Shailesh Singh. Potential role of CXCR6-CXCL16 in prostate cancer progression and chemotherapeutic efficacy. [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 4047. doi:10.1158/1538-7445.AM2014-4047

Abstract 2128: The effects of Quercetin on prostate cancer

Prostate cancer (PCa) affects nearly 80% of men worldwide and is the second leading killer after lung cancer. The efficacy of current treatments offered in the clinics is highly compromised due to indolent nature of PCa, which provides large window of opportunity for prevention. Hence, the major focus of this study is to determine the chemo-preventive effects of Quercetin, a bioflavonoid, on prostate cancer. Effect of Quercetin on cell viability and IC50 was determined by MTT assay. The effect of Quercetin on cell motility was determined by wound healing assay. Potential role of Quercetin on cell cycle, apoptosis as well as genes involved in cell motility and invasion was determined using flow cytometry, Real-time qPCR and ELISA. Furthermore, Quercetin induced changes in signaling molecules involved in cell survival/apoptosis, cell cycle and cytoskeletal rearrangement was determined using antibody microarray. Prostate cancer cells treated with Quercetin showed dose and time dependent inhibition of proliferation/viability, and induction of apoptosis as compared to normal prostatic epithelial cells and untreated controls. Prostate cancer cell motility was inhibited in Quercetin treated cells. Prostate cancer cells were arrested in G2 phase of the cell cycle following Quercetin treatment. In addition to these, we found differential expression of caspases, matrix metalloproteinases (MMPs) and tissue inhibitor of MMPs in different PCa cell lines compared to untreated controls. Furthermore, antibody microarray analysis demonstrated selective modulation of genes and associated signaling cascades responsible for apoptosis induction, cellular motility, adhesion and invasion in Quercetin treated cells compared to controls. These findings suggest Quercetin as a potent chemo-preventive agent. In addition to this it can be also used with chemotherapeutic agents directed to G2 phase of the cell cycle, which may improve the efficacy of chemotherapeutics offered in clinics to treat advance prostate cancer.

Citation Format: Ashley B. Ward, Pranav Gupta, Gurpreet Kaur, Hina Mir, James W. Lillard, Shailesh Singh. The effects of Quercetin on prostate cancer. [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 2128. doi:10.1158/1538-7445.AM2014-2128

Proteases involved during oxidative stress-induced poly(ADP-ribose) polymerase-mediated cell death in Dictyostelium discoideum

Apoptosis involves a cascade of caspase activation leading to the ordered dismantling of critical cell components. However, little is known about the dismantling process in non-apoptotic cell death where caspases are not involved. Dictyostelium discoideum is a good model system to study caspase-independent cell death where experimental accessibility of non-apoptotic cell death is easier and molecular redundancy is reduced compared with other animal models. Poly(ADP-ribose) polymerase (PARP) is one of the key players in cell death. We have previously reported the role of PARP in development and the oxidative stress-induced cell death of D. discoideum. D. discoideum possesses nine PARP genes and does not have a caspase gene, and thus it provides a better model system to dissect the role of PARP in caspase-independent cell death. The current study shows that non-apoptotic cell death in D. discoideum occurs in a programmed fashion where proteases cause mitochondrial membrane potential changes followed by plasma membrane rupture and early loss of plasma membrane integrity. Furthermore, the results suggest that calpains and cathepsin D, which are instrumental in dismantling the cell, act downstream of PARP. Thus, PARP, apoptosis inducing factor, calpains and cathepsin D are the key players in D. discoideum caspase-independent cell death, acting in a sequential manner.

A novel recessive mutation in the gene ELOVL4 causes a neuro-ichthyotic disorder with variable expressivity

Background

A rare neuro-ichthyotic disorder characterized by ichthyosis, spastic quadriplegia and intellectual disability and caused by recessive mutations in ELOVL4, encoding elongase-4 protein has recently been described. The objective of the study was to search for sequence variants in the gene ELOVL4 in three affected individuals of a consanguineous Pakistani family exhibiting features of neuro-ichthyotic disorder.

Methods

Linkage in the family was searched by genotyping microsatellite markers linked to the gene ELOVL4, mapped at chromosome 6p14.1. Exons and splice junction sites of the gene ELOVL4 were polymerase chain reaction amplified and sequenced in an automated DNA sequencer.

Results

DNA sequence analysis revealed a novel homozygous nonsense mutation (c.78C > G; p.Tyr26*).

Conclusions

Our report further confirms the recently described ELOVL4-related neuro-ichthyosis and shows that the neurological phenotype can be absent in some individuals.

Modelling Behaviour of PET for Stretch and Micro-Blow Moulding Applications Using an Elasto-Visco-Plastic Material Model

Polyethylene terephthalate (PET) has been widely used in the stretch blow moulding (SBM) process for packaging applications. Finite element analysis has become extensively useful for assessing container designs and enabling the designers to perform analyses earlier in the design cycle to determine the best material and the best structure. However, there are several challenging issues due to various processing parameters and complex material behaviour, which is both temperature and strain-rate dependent. In this paper, we generalize the G'Sell-Jonas law in the three-dimensional (3D) case to model and simulate the elasto-visco-plastic (EVP) behaviour of PET, taking into account strain-hardening and strain-softening. In addition, it is observed that the internal pressure (inside the preform) is significantly different from the nominal pressure (imposed in the blowing device upstream) since the internal pressure and the enclosed volume of the preform are fully coupled. In order to accurately simulate this phenomenon, a thermodynamic model was used to characterize the pressure-volume relationship (PVR). The predicted pressure evolution is therefore more realistic when imposing only the machine power of the blowing device (air compressor or vacuum pump). Mechanical and temperature equilibrium equations are fully nonlinear and solved separately with implicit schemes on the current deformed configuration, which is updated at each time step. Biaxial characterization tests were used to determine the model parameters in order to simulate the SBM process using the PVR. Three industrial case studies, comparing simulated thickness predictions to experimental measurements, will be presented in order to illustrate the applicability of the proposed model.

Staurosporine induced poly (ADP-ribose) polymerase independent cell death in Dictyostelium discoideum

In the present study D. discoideum has been used as a model organism to understand the role of poly (ADP-ribose) polymerase (PARP) in caspase independent paraptotic cell death pathways. D. discoideum lacks caspases and Bcl-2 family proteins; nevertheless it has 9 potential genes for PARP. PARP has been known to get activated in various cell death associated diseases. In this study kinetics of cell death induced by staurosporine (STS), a bacterial alkaloid, was established to unravel the role of PARP. It was found that STS induced cell death in D. discoideum did not involve PARP activation, however it involved cathepsin D. Results indicated that an alternative mechanism may be existing in D. discoideum that lacks Bcl-2 family proteins for STS induced cell death that evades Bax involvement.

Differential role of poly(ADP-ribose) polymerase in D. discoideum growth and development

BACKGROUND

Poly(ADP-ribose) polymerase is evolutionarily conserved as a responder to various forms of stress. Though PARP's role in cell death is well addressed, its role in development and multicellularity is still an enigma. We have previously reported the role of PARP in oxidative stress induced delayed development of D. discoideum.

RESULTS

In the current study we highlight the involvement of PARP during D. discoideum development. Oxidative stress affects expression of aca and cAR1 thus affecting aggregation. Although parp expression is not affected during oxidative stress but it is involved during normal development as confirmed by our PARP down-regulation studies. Constitutive PARP down-regulation resulted in blocked development while no effect was observed on D. discoideum growth. Interestingly, stage specific PARP down-regulation arrested development at the slug stage.

CONCLUSION

These results emphasize that PARP is essential for complex differentiation and its function may be linked to multicellularity. This is the first report where the involvement of PARP during normal multicellular development in D. discoideum, an ancient eukaryote, is established which could be of evolutionary significance. Thus our study adds one more role to the multitasking function of PARP.

Mutation analysis of the ASPM gene in 18 Pakistani families with autosomal recessive primary microcephaly

Autosomal recessive primary microcephaly (MCPH) is a rare neurological disorder, in which the patients exhibit reduced occipital frontal head circumference (>3 standard deviations) and mild-to-severe mental retardation. Autosomal recessive primary microcephaly is genetically heterogeneous and 7 loci have been reported to date. Mutations in ASPM (abnormal spindle-like, microcephaly associated) gene are the most common cause of autosomal recessive primary microcephaly in the majority of the reported families. In the current investigation, we have located and studied 21 families with autosomal recessive primary microcephaly. Genotyping using polymorphic microsatellite markers linked to 7 autosomal recessive primary microcephaly loci revealed linkage of 18 families to the MCPH5 locus. Sequence analysis of the ASPM gene in 18 linked families detected 2 novel nonsense mutations (c.2101C>T/p.Q701X; c.9492T>G/p.Y3164X) in 2 families and 2 novel deletion mutations (c.6686delGAAA/p.R2229TfsX9; c.77delG/p.G26AfsX41) in 2 other families. Three previously described mutations (c.3978G>A/p.W1326X; c.1260delTCAAGTC/p.S420SfsX32; c.9159delA/p.K3053NfsX4) were also detected in 11 families. These identified mutations extended the body of evidence implicating the ASPM gene in the pathogenesis of human hereditary primary microcephaly.

Delayed repair of congenital diaphragmatic hernia with early high-frequency oscillatory ventilation during preoperative stabilization

PURPOSE

The authors reviewed their experience in the management of CDH after the introduction of early high-frequency oscillatory ventilation (HFOV) during the preoperative stabilization period and delayed CDH repair.

METHODS

This is a retrospective analysis of 24 consecutive infants with CDH treated at University of California, Irvine Medical Center (UCIMC) during a 36-month period from January 1993 to December 1996.

RESULTS

Two patients were excluded from the study: one fetus with a prenatal diagnosis was referred for fetal surgery; one infant received CDH repair at another institution 2 weeks before transfer to UCIMC. Eight (36%) infants were inborn, and nine (41%) had a prenatal diagnosis of CDH. Median gestational age was 40 weeks (range, 29 to 42 weeks). Median birth weight was 3,019 g (range, 1,205 to 4,337 g). The defect was left sided in 18 infants (86%). Twenty-one infants were intubated within 5 hours of life, 15 had an AaDO2 greater than 610, 11 had an oxygenation index greater than 40, and 11 had a pH of less than 7.2. The median ratio of pulmonary artery pressure to systemic blood pressure was 0.93 (range, 0.51 to 1.15) in 12 infants. Eighteen infants were placed on HFOV within a median of 1 hour of life. Nitric oxide was given to six infants and surfactant to eight. Four infants were referred for extracorporeal membrane oxygenation (ECMO). Repair of CDH was performed on infants at a median age of 33.5 hours (range, 5.5 to 322). Six (30%) received a prosthetic patch. Overall 18 of 22 infants survived (81%); three survivors received ECMO. Two infants of the survivor group had congenital heart anomalies: one ventricular septal defect (VSD) and one double-outlet right ventricle with a VSD. Of the four nonsurvivors, one had lethal cardiac anomalies and bilateral CDH, two had severe bilateral pulmonary hypoplasia (one received ECMO), and one infant was a 29-week premature baby who did not qualify for ECMO.

CONCLUSION

We report a survival rate of 81% (18 of 22) with the management of CDH by delayed surgical repair, early postnatal HFOV, and selective referral for ECMO.