Pancreatic cancer cells resistance to gemcitabine: the role of MUC4 mucin

BACKGROUND: A major obstacle to the successful management of pancreatic cancer is to acquire resistance to the existing chemotherapeutic agents. Resistance to gemcitabine, the standard first-line chemotherapeutic agent for advanced and metastatic pancreatic cancer, is mainly attributed to an altered apoptotic threshold in the pancreatic cancer. The MUC4 transmembrane glycoprotein is aberrantly overexpressed in the pancreatic cancer and recently, has been shown to increase pancreatic tumour cell growth by the inhibition of apoptosis. METHODS: Effect of MUC4 on pancreatic cancer cells resistance to gemcitabine was studied in MUC4-expressing and MUC4-knocked down pancreatic cancer cell lines after treatment with gemcitabine by Annexin-V staining, DNA fragmentation assay, assessment of mitochondrial cytochrome c release, immunoblotting and co-immunoprecipitation techniques. RESULTS: Annexin-V staining and DNA fragmentation experiment demonstrated that MUC4 protects CD18/HPAF pancreatic cancer cells from gemcitabine-induced apoptosis. In concert with these results, MUC4 also attenuated mitochondrial cytochrome c release and the activation of caspase-9. Further, our results showed that MUC4 exerts anti-apoptotic function through HER2/extracellular signal-regulated kinase-dependent phosphorylation and inactivation of the pro-apoptotic protein Bad. CONCLUSION: Our results elucidate the function of MUC4 in imparting resistance to pancreatic cancer cells against gemcitabine through the activation of anti-apoptotic pathways and, thereby, promoting cell survival

CCR9-CCL25 interactions promote cisplatin resistance in breast cancer cell through Akt activation in a PI3K-dependent and FAK-independent fashion

<p>Abstract</p> <p>Background</p> <p>Chemotherapy heavily relies on apoptosis to kill breast cancer (BrCa) cells. Many breast tumors respond to chemotherapy, but cells that survive this initial response gain resistance to subsequent treatments. This leads to aggressive cell variants with an enhanced ability to migrate, invade and survive at secondary sites. Metastasis and chemoresistance are responsible for most cancer-related deaths; hence, therapies designed to minimize both are greatly needed. We have recently shown that CCR9-CCL25 interactions promote BrCa cell migration and invasion, while others have shown that this axis play important role in T cell survival. In this study we have shown potential role of CCR9-CCL25 axis in breast cancer cell survival and therapeutic efficacy of cisplatin.</p> <p>Methods</p> <p>Bromodeoxyuridine (BrdU) incorporation, Vybrant apoptosis and TUNEL assays were performed to ascertain the role of CCR9-CCL25 axis in cisplatin-induced apoptosis of BrCa cells. Fast Activated Cell-based ELISA (FACE) assay was used to quantify <it>In situ </it>activation of PI3K^p85, Akt^Ser473, GSK-3β^Ser9and FKHR^Thr24in breast cancer cells with or without cisplatin treatment in presence or absence of CCL25.</p> <p>Results</p> <p>CCR9-CCL25 axis provides survival advantage to BrCa cells and inhibits cisplatin-induced apoptosis in a PI3K-dependent and focal adhesion kinase (FAK)-independent fashion. Furthermore, CCR9-CCL25 axis activates cell-survival signals through Akt and subsequent glycogen synthase kinase-3 beta (GSK-3β) and forkhead in human rhabdomyosarcoma (FKHR) inactivation. These results show that CCR9-CCL25 axis play important role in BrCa cell survival and low chemotherapeutic efficacy of cisplatin primarily through PI3K/Akt dependent fashion.</p

WAP four-disulfide core domain protein 2 gene(WFDC2) is a target of estrogen in ovarian cancer cells

BACKGROUND: WAP four-disulfide core domain protein 2 (WFDC2) shows a tumor-restricted upregulated pattern of expression in ovarian cancer. METHODS: We investigated the role of estradiol (E2) on cell growth in estrogen-sensitive or estrogen-insensitive ovarian cancer cell lines. Real-time (RT)-PCR and western blotting were used to examine the expression of WFDC2 at RNA and protein levels. Growth traits of cells transfected with WFDC2-shRNA or blank control were assessed using MMT arrays. Cell apoptosis was analyzed using annexin V-FITC/PI and flow cytometry. Estrogen receptor expression was evaluated using RT-PCR and flow cytometry. Apoptosis-related proteins induced by E2 directly and indirectly were determined using an antibody array comparing cells transfected with WFDC2- shRNA or a blank control. RESULTS: High-dose (625 ng/ml) E2 increased the expression of WFDC2 in HO8910 cells at both the mRNA and protein levels. However, E2 had no effect on WFDC2 expression in estrogen-insensitive SKOV3 cells. Of interest, knockdown of WFDC2 enabled a considerable estrogen response in SKOV3 cells in terms of proliferation, similar to estrogen-responsive HO8910 cells. This transformation of SKOV3 cells into an estrogen-responsive phenotype was accompanied by upregulation of estrogen receptor beta (ERß) and an effect on cell apoptosis under E2 treatment by regulating genes related to cell proliferation and apoptosis. CONCLUSIONS: We postulate that increased WFDC2 expression plays an important role in altering the estrogen pathway in ovarian cancer, and the identification of WFDC2 as a new player in endocrine-related cancer encourages further studies on the significance of this gene in cancer development and therapy. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s13048-015-0210-y) contains supplementary material, which is available to authorized users

Mothers' accounts of their stillbirth experiences and of their subsequent relationships with their living infant:an interpretative phenomenological analysis

BACKGROUND: Due to contradictory findings regarding the effects of seeing and holding stillborn infants on women's worsening mental health symptoms, there is a lack of clear of guidance in stillbirth bereavement care. Although some current research examines this phenomenon we are still not certain of the meaning of such experiences to women and what effects there may be on her subsequent parenting. Thus the present study focuses on the meaning of the stillbirth experience to women and its influence on the subsequent pregnancy and subsequent parenting from the mothers' own experiences. METHODS: A purposive sample of six women who experienced a stillbirth during their first pregnancy and who then went on to give birth to a living child after a further pregnancy, took part in email interviews, providing rich and detailed experiential narratives about both the stillbirth itself, and their relationship with their living child. An Interpretive Phenomenological Analysis was carried out in order to focus on mothers making sense of such experiences. RESULTS: Analysis of written accounts led to the development of three overarching themes. In 'Broken Canopy', 'How This Happened' and 'Continuing Bonds', their accounts revealed an ongoing process where women accepted a new 'unsafe' view of the world, re-evaluated their view of self and others, and established relationships with both the deceased and the living infant. CONCLUSIONS: This study provided an insight into the stillbirth experience of mothers and its meaning to them with an existential focus. Typically the mother struggled with the contradictory process of accepting the existence of her deceased baby (this baby once lived) while being aware of the nonexistence (this baby). Meeting the dead baby was a crucial point at which the mother started processing her grief. The importance of individual differences in dealing with stressful situations was highlighted in terms of attachment strategies. Subsequent parenting experiences of mothers were very much influenced by their own previous experiences. Although some mothers managed to integrate this trauma into their life some remained very concerned and anxious about future and this anxiety then translated into their parenting experiences

Protein-Binding Microarray Analysis of Tumor Suppressor AP2α Target Gene Specificity

Cheap and massively parallel methods to assess the DNA-binding specificity of transcription factors are actively sought, given their prominent regulatory role in cellular processes and diseases. Here we evaluated the use of protein-binding microarrays (PBM) to probe the association of the tumor suppressor AP2α with 6000 human genomic DNA regulatory sequences. We show that the PBM provides accurate relative binding affinities when compared to quantitative surface plasmon resonance assays. A PBM-based study of human healthy and breast tumor tissue extracts allowed the identification of previously unknown AP2α target genes and it revealed genes whose direct or indirect interactions with AP2α are affected in the diseased tissues. AP2α binding and regulation was confirmed experimentally in human carcinoma cells for novel target genes involved in tumor progression and resistance to chemotherapeutics, providing a molecular interpretation of AP2α role in cancer chemoresistance. Overall, we conclude that this approach provides quantitative and accurate assays of the specificity and activity of tumor suppressor and oncogenic proteins in clinical samples, interfacing genomic and proteomic assays

Treatment of PC3 prostate cancer cells with mitoxantrone, etoposide, doxorubicin and carboplatin induces distinct alterations in the expression of kallikreins 5 and 11

Several of the novel kallikrein-related peptidases (tissue kallikreins; KLKs) are emerging new serum and/or tissue biomarkers for prostate cancer (CaP) diagnosis, prognosis and monitoring. In the present research approach, our objective was to investigate the possible alterations in the mRNA expression levels of KLKS and KLK11 genes in prostate cancer cells PC3 as a response to treatment with Mitoxantrone, Etoposide, Doxorubicin and Carboplatin. Viability was assessed with the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoIium bromide) assay after cell treatment with either mitoxantrone (2 μM), etoposide (20 μM),doxorubicin (I μM),or carboplatin (15 μM),for 24,48 and 72 hours. Additionally, trypan blue staining revealed that in PC3 cells all drugs displayed almost the same limited necrotic effects which appeared mainly at 72 hours of treatment. PC3 prostate cancer cells showed a concentration- and time-dependent increased cytotoxicity to the drugs under study which was mainly due to reduction of cell proliferation efficiency. Distinct modulations of KLKS and KLK11 genes, at the mRNA level, were observed, supporting a drug-dependent cell response. Our experimental data demonstrate that the molecular profile mainly of KLK5 gene may serve as a new potential molecular biomarker predicting treatment response in CaP cells. © 2009 Schattauer GmbH