http://www.molecular-cancer.com The latest research articles published by Molecular Cancer 2009-07-03T00:00:00Z This is an RSS newsfeed from BioMed Central It is intended to be used with an RSS reader. For more information about RSS newsfeeds from BioMed Central, visit http://www.biomedcentral.com/info/about/rss/ Background: Survivin is a dual function protein. It inhibits the apoptosis of cells by inhibiting caspases, and also promotes cell growth by stabilizing microtubules during mitosis. Over-expression of survivin has been demonstrated to induce drug-resistance to various chemo-therapeutic agents such as cisplatin (DNA damaging agent) and paclitaxel (microtubule stabilizer) in cancers. However, survivin-induced resistant to microtubule de-stabilizers such as Vinca alkaloids and Combretastatin A-4 (CA-4)-related compounds were seldom demonstrated in the past. Furthermore, question remains as to whether survivin plays a dominant role in processing cytokinesis or inhibiting caspases activity in cells treated with anti-mitotic compounds. The purpose of this study is to evaluate the effect of survivin on the resistance and susceptibility of human cancer cells to microtubule de-stabilizer-induced cell death. Results: BPR0L075 is a CA-4 analog that induces microtubule de-polymerization and subsequent caspase-dependent apoptosis. To study the relationship between the expression of survivin and the resistance to microtubule de-stabilizers, a KB-derived BPR0L075-resistant cancer cell line, KB-L30, was generated for this study. Here, we found that survivin was over-expressed in the KB-L30 cells. Down-regulation of survivin by siRNA induced hyper-sensitivity to BPR0L075 in KB cells and partially re-stored sensitivity to BPR0L075 in KB-L30 cells. Western blot analysis revealed that down-regulation of survivin induced microtubule de-stabilization in both KB and KB-L30 cells. However the same treatment did not enhance the down-stream caspase-3/-7 activities in BPR0L075-treated KB cells. Translocation of a caspase-independent apoptosis-related molecule, apoptosis-inducing factor (AIF), from cytoplasm to the nucleus was observed in survivin-targeted KB cells under BPR0L075 treatment. Conclusions: In this study, survivin plays an important role in the stability of microtubules, but not with caspases inhibition. Over-expression of survivin counteracts the therapeutic effect of microtubule de-stabilizer BPR0L075 probably by stabilizing tubulin polymers, instead of the inhibition of caspase activity in cancer cells. Besides microtubule-related caspase-dependent cell death, caspase-independent mitotic cell death could be initiated in survivin/BPR0L075 combination treatments. We suggest that combining microtubule de-stabilizers and survivin inhibitor may attributes better clinical outcome than the use of anti-mitotic monotherapy in clinical situations. http://www.molecular-cancer.com/content/8/1/43 Chun Hei Antonio Cheung Huang-Hui Chen Ching-Chuan Kuo Chi-Yen Chang Mohane Coumar Hsing-Pang Hsieh Jang-Yang Chang Molecular Cancer 2009, 8:43 2009-07-03T00:00:00Z doi:10.1186/1476-4598-8-43 Molecular Cancer 1476-4598 8 43 2009-07-03T00:00:00Z PDF Background: The Ras-assocation family (RASSF) of tumour suppressor genes (TSGs) contains 10 members that encode proteins containing Ras-assocation (RA) domains. Several members of the RASSF family are frequently epigenetically inactivated in cancer, however, their role in leukaemia has remained largely uninvestigated. Also, RASSF10 is a predicted gene yet to be experimentally verified. Here we cloned, characterised and demonstrated expression of RASSF10 in normal human bone marrow. We also determined the methylation status of CpG islands associated with RASSF1-10 in a series of childhood acute lymphocytic leukaemias (ALL) and normal blood and bone marrow samples. Results: COBRA and bisulphite sequencing revealed RASSF6 and RASSF10 were the only RASSF members with a high frequency of leukaemia-specific methylation. RASSF6 was methylated in 94% (48/51) B-ALL and 41% (12/29) T-ALL, whilst RASSF10 was methylated in 16% (8/51) B-ALL and 88% (23/26) T-ALL. RASSF6 and RASSF10 expression inversely correlated with methylation which was restored by treatment with 5-aza-2'deoxycytidine (5azaDC). Conclusion: This study shows the hypermethylation profile of RASSF genes in leukaemias is distinct from that of solid tumours and represents the first report of inactivation of RASSF6 or RASSF10 in cancer. These data show epigenetic inactivation of RASSF6 and RASSF10 is an extremely frequent event in the pathogenesis of childhood leukaemia. This study also warrants further investigation of the newly identified RASSF member RASSF10 and its potential role in leukaemia. http://www.molecular-cancer.com/content/8/1/42 Luke Hesson Thomas Dunwell Wendy Cooper Daniel Catchpoole Anna Brini Raffaella Chiaramonte Mike Griffiths Andrew Chalmers Eamonn Maher Farida Latif Molecular Cancer 2009, 8:42 2009-07-01T00:00:00Z doi:10.1186/1476-4598-8-42 Molecular Cancer 1476-4598 8 42 2009-07-01T00:00:00Z PDF Background: Metabolic perturbations arising from malignant transformation have not been systematically characterized in human lung cancers in situ. Stable isotope resolved metabolomic analysis (SIRM) enables functional analysis of gene dysregulations in lung cancer. To this purpose, metabolic changes were investigated by infusing uniformly labeled 13C-glucose into human lung cancer patients, followed by resection and processing of paired non-cancerous lung and non small cell carcinoma tissues. NMR and GC-MS were used for 13C-isotopomer-based metabolomic analysis of the extracts of tissues and blood plasma. Results: Many primary metabolites were consistently found at higher levels in lung cancer tissues than their surrounding non-cancerous tissues. 13C-enrichment in lactate, Ala, succinate, Glu, Asp, and citrate was also higher in the tumors, suggesting more active glycolysis and Krebs cycle in the tumor tissues. Particularly notable were the enhanced production of the Asp isotopomer with three 13C-labeled carbons and the buildup of 13C-2,3-Glu isotopomer in lung tumor tissues. This is consistent with the transformations of glucose into Asp or Glu via glycolysis, anaplerotic pyruvate carboxylation (PC), and the Krebs cycle. PC activation in tumor tissues was also shown by an increased level of pyruvate carboxylase mRNA and protein. Conclusions: PC activation - revealed here for the first time in human subjects - may be important for replenishing the Krebs cycle intermediates which can be diverted to lipid, protein, and nucleic acid biosynthesis to fulfill the high anabolic demands for growth in lung tumor tissues. We hypothesize that this is an important event in non-small cell lung cancer and possibly in other tumor development. http://www.molecular-cancer.com/content/8/1/41 Teresa Fan Andrew Lane Richard Higashi Mohamed Farag Hong Gao Michael Bousamra Donald Miller Molecular Cancer 2009, 8:41 2009-06-26T00:00:00Z doi:10.1186/1476-4598-8-41 Molecular Cancer 1476-4598 8 41 2009-06-26T00:00:00Z PDF The zebrafish has become an important model for cancer research. Several cancer models have been established by transgenic expression of human or mouse oncogenes in zebrafish. Since it is amenable to efficient transgenesis, zebrafish has immense potential to be used for studying interaction of oncogenes and pathways at the organismal level. Using the Gal4VP16-UAS binary transgenic expression approach, we established stable transgenic lines expressing an EGFP tagged activated zebrafish smoothened (smoa1). Expression of the zebrafish smoa1 itself did not lead to tumor formation either in founder fish or subsequent generations. Neither did expression of a constitutively active form of human AKT1. However, co-expression of the two oncogenes resulted in several tumor types, including spindle cell sarcoma, rhabdomyoma, ocular melanoma, astrocytoma and so on. All tumor types showed GFP expression, suggesting involvement of zebrafish smoa1 in tumorigenesis. Immunofluorescence studies showed that tumors also expressed elevated levels of phosphorylated AKT, indicating activation of the PI3K-AKT pathway. These results suggest that co-activation of the hedgehog and AKT pathways promote tumorigenesis, and the binary transgenic approach may become an invaluable tool for studying interaction of oncogenes and oncogenic pathways in zebrafish. http://www.molecular-cancer.com/content/8/1/40 Bensheng Ju Jan Spitsbergen Christopher Eden Michael Taylor Wenbiao Chen Molecular Cancer 2009, 8:40 2009-06-25T00:00:00Z doi:10.1186/1476-4598-8-40 Molecular Cancer 1476-4598 8 40 2009-06-25T00:00:00Z PDF Background: Manipulating apoptotic resistance represents an important strategy for the treatment of hormone refractory prostate cancer. We hypothesised that the Inhibitor of Apoptosis (IAP) Proteins may be mediating this resistance and knockdown of cIAP-1, cIAP-2 and XIAP would increase sensitivity to apoptosis. Methods: cIAP-1, cIAP-2 and XIAP where knocked down either individually or in combination using siRNA in androgen independent prostate cancer PC-3 cells as confirmed by real-time PCR and western blotting. Cells were then treated with TRAIL, Etoposide, or Tunicamycin, and apoptosis assessed by PI DNA staining. Apoptosis was confirmed with Annexin V labelling and measurement of PARP cleavage, and was inhibited using the pan-caspase inhibitor, zVAD.fmk. Clonogenic assays and assessment of ID-1 expression by western blotting were used to measure recovery and proliferation. Results: PC-3 are resistant to TRAIL induced apoptosis and have elevated expression of cIAP-1, cIAP-2 and XIAP. Combined knockdown sensitised PC-3 to TRAIL induced apoptosis, but not to Etoposide or Tunicmycin, with corresponding increases in caspase activity and PARP cleavage which was inhibited by ZVAD.fmk. Triple knock down decreased proliferation which was confirmed by decreased ID-1 expression. Conclusion: Simultaneous knock down of the IAPs not only sensitised the PC-3 to TRAIL but also inhibited their proliferation rates and clonogenic survival. The inability to alter sensitivity to other triggers of apoptosis suggests that this effect is specific for death receptor pathways and knock down might facilitate immune-surveillance mechanisms to counter cancer progression and, in combination with therapeutic approaches using TRAIL, could represent an important treatment strategy. http://www.molecular-cancer.com/content/8/1/39 Catherine Gill Catherine Dowling Amanda O'Neill R. William Watson Molecular Cancer 2009, 8:39 2009-06-23T00:00:00Z doi:10.1186/1476-4598-8-39 Molecular Cancer 1476-4598 8 39 2009-06-23T00:00:00Z PDF Background: Tuberous sclerosis (TSC) is a hamartoma syndrome in which renal and lung tumors cause the greatest morbidity. Loss of either TSC1 or TSC2 in TSC hamartomas leads to activation of mTORC1 and suppression of AKT. Recent studies indicate that inhibition of mTORC1 with RAD001 (everolimus) leads to rebound activation of AKT, which could protect tumors from drug-induced cell death. Here we examine the potential benefit of inhibition of both mTOR and AKT signaling in a mouse model of TSC, using a dual pan class I PI3K/mTOR catalytic small molecule inhibitor NVP-BEZ235. Results: Using ENU to enhance Tsc2+- kidney tumor development, both RAD001 (10 mg/kg PO 5 d/week) and NVP-BEZ235 (45 mg/kg PO QD) had equivalent effects in suppressing tumor development during a 4 week treatment period, with a 99% reduction in tumor cell mass. Marked reduction in activation of mTORC1, induction of cell cycle arrest, and absence of apoptotic cell death was seen in mice treated with either drug. However, when either was discontinued, there was prompt recovery of tumor growth, with extensive proliferation. Conclusion: Both mTORC1 blockade alone and combined PI3K-mTOR blockade lead to suppression of tumor development but not tumor elimination in this TSC model. http://www.molecular-cancer.com/content/8/1/38 Kristen Pollizzi Izabela Malinowska-Kolodziej Michael Stumm Heidi Lane David Kwiatkowski Molecular Cancer 2009, 8:38 2009-06-15T00:00:00Z doi:10.1186/1476-4598-8-38 Molecular Cancer 1476-4598 8 38 2009-06-15T00:00:00Z XML Background: Pancreatic cancer (PaCa) is a fatal human cancer due to its exceptional resistance to all current anticancer therapies. The cytoprotective enzyme heme oxygenase-1 (HO-1) is significantly overexpressed in PaCa and seems to play an important role in cancer resistance to anticancer treatment. The inhibition of HO-1 sensitized PaCa cells to chemo- and radiotherapy in vitro.Therefore, we investigated the effects of HO-1 and its metabolites biliverdin, carbon monoxide and iron on PaCa cells.PaCa cell lines with divergent HO-1 expression patterns were used in a murine orthotopic cancer model. HO-1 expression and activity was regulated by zinc (inhibition) and cobalt (induction) protoporphyrin. Furthermore, the influence of cellular HO-1 levels and its metabolites on effects of standard chemotherapy with gemcitabine was tested in vivo and in vitro. Results: High HO-1 expression in PaCa cell lines was associated with increased chemoresistance in vitro. Chemoresistance to gemcitabine was increased during HO-1 induction in PaCa cells expressing low levels of HO-1. The inhibition of HO-1 activity in pancreatic tumors with high HO-1 boosted chemotherapeutic effects in vivo significantly. Furthermore, biliverdin and iron promoted PaCa resistance to chemotherapy. Consequently, specific iron chelation by desferrioxamine revealed profound anticancerous effects. Conclusion: In summary, the inhibition of HO-1 and the chelation of iron in PaCa cells were associated with increased sensitivity and susceptibility of pancreatic tumors to chemotherapy in vivo. The metabolites biliverdin and iron seem to be involved in HO-1-mediated resistance to anticancer treatment. Therefore, HO-1 inhibition or direct interference with its metabolites may evolve new PaCa treatment strategies. http://www.molecular-cancer.com/content/8/1/37 Philipp Nuhn Beat Kunzli Rene Hennig Tomas Mitkus Tadas Ramanauskas Rainer Nobiling Stefan Meuer Helmut Friess Pascal Berberat Molecular Cancer 2009, 8:37 2009-06-09T00:00:00Z doi:10.1186/1476-4598-8-37 Molecular Cancer 1476-4598 8 37 2009-06-09T00:00:00Z XML Background: The HMGA2 gene encodes a protein that alters chromatin structure. Deregulation, typically through chromosomal rearrangements, of HMGA2 has an important role in the development of several mesenchymal neoplasms. These rearrangements result in the expression of a truncated protein lacking the acidic C-terminus, a fusion protein consisting of the AT-hook domains encoded by exons 1–3 and parts from another gene, or a full-length protein; loss of binding sites for regulatory microRNA molecules from the 3' untranslated region (UTR) of HMGA2 has been suggested to be a common denominator. Methods: Seventy adipocytic tumors, representing different morphologic and cytogenetic subgroups, were analyzed by qRT-PCR to study the expression status of HMGA2; 18 of these tumors were further examined by PCR to search for mutations or deletions in the 3'UTR. Results: Type (full-length or truncated) and level of expression varied with morphology and karyotype, with the highest levels in atypical lipomatous tumors and lipomas with rearrangements of 12q13-15 and the lowest in lipomas with 6p- or 13q-rearrangements, hibernomas, spindle cell lipomas and myxoid liposarcomas. All 18 examined tumors showed reduced or absent expression of the entire, or parts of, the 3'UTR, which was not due to mutations at the DNA level. Conclusion: In adipocytic tumors with deregulated HMGA2 expression, the 3'UTR is consistently lost, either due to physical disruption of HMGA2 or a shift to production of shorter 3'UTR. http://www.molecular-cancer.com/content/8/1/36 Hammurabi Bartuma Ioannis Panagopoulos Anna Collin Domenico Trombetta Henryk Domanski Nils Mandahl Fredrik Mertens Molecular Cancer 2009, 8:36 2009-06-09T00:00:00Z doi:10.1186/1476-4598-8-36 Molecular Cancer 1476-4598 8 36 2009-06-09T00:00:00Z XML Background: Dysregulated Notch signalling is believed to play an important role in the development and maintenance of T cell leukaemia. At a cellular level, Notch signalling promotes proliferation and inhibits apoptosis of T cell acute lymphoblastic leukaemia (T-ALL) cells. In this study we aimed to identify novel transcriptional targets of Notch signalling in the T-ALL cell line, Jurkat. Results: RNA was prepared from Jurkat cells retrovirally transduced with an empty vector (GFP-alone) or vectors containing constitutively active forms of Notch (N1ΔE or N3ΔE), and used for Affymetrix microarray analysis. A subset of genes found to be regulated by Notch was chosen for real-time PCR validation and in some cases, validation at the protein level, using several Notch-transduced T-ALL and non-T-ALL leukaemic cell lines. As expected, several known transcriptional target of Notch, such as HES1 and Deltex, were found to be overexpressed in Notch-transduced cells, however, many novel transcriptional targets of Notch signalling were identified using this approach. These included the T cell costimulatory molecule CD28, the anti-apoptotic protein GIMAP5, and inhibitor of DNA binding 1 (1D1). Conclusion: The identification of such downstream Notch target genes provides insights into the mechanisms of Notch function in T cell leukaemia, and may help identify novel therapeutic targets in this disease. http://www.molecular-cancer.com/content/8/1/35 Nicholas Chadwick Leo Zeef Virginia Portillo Carl Fennesy Fiona Warrander Sarah Hoyle Anne-Marie Buckle Molecular Cancer 2009, 8:35 2009-06-09T00:00:00Z doi:10.1186/1476-4598-8-35 Molecular Cancer 1476-4598 8 35 2009-06-09T00:00:00Z XML Background: Wee1 is a tyrosine kinase regulating S-G2 cell cycle transition through the inactivating phosphorylation of CDC2. The inhibition of Wee1 kinase by a selective small molecule inhibitor significantly enhances the anti-tumor efficacy of DNA damaging agents, specifically in p53 negative tumors by abrogating S-G2 checkpoints, while normal cells with wild-type p53 are not severely damaged due to the intact function of the G1 checkpoint mediated by p53. Since the measurement of mRNA expression requires a very small amount of biopsy tissue and is highly quantitative, the development of a pharmacodynamic (PD) biomarker leveraging mRNA expression is eagerly anticipated in order to estimate target engagement of anti-cancer agents. Results: In order to find the Wee1 inhibition signature, mRNA expression profiling was first performed in both p53 positive and negative cancer cell lines treated with gemcitabine and a Wee1 inhibitor, MK-1775. We next carried out mRNA expression profiling of skin samples derived from xenograft models treated with the Wee1 inhibitor to identify a Wee1 inhibitor-regulatory gene set. Then, the genes that were commonly modulated in both cancer cell lines and rat skin samples were extracted as a Wee1 inhibition signature that could potentially be used as a PD biomarker independent of p53 status. The expression of the Wee1 inhibition signature was found to be regulated in a dose-dependent manner by the Wee1 inhibitor, and was significantly correlated with the inhibition level of a direct substrate, phosphorylated-CDC2. Individual genes in this Wee1 inhibition signature are known to regulate S-G2 cell cycle progression or checkpoints, which is consistent with the mode-of-action of the Wee1 inhibitor. Conclusion: We report here the identification of an mRNA gene signature that was specifically changed by gemcitabine and Wee1 inhibitor combination treatment by molecular profiling. Given the common regulation of expression in both xenograft tumors and animal skin samples, the data suggest that the Wee1 inhibition gene signature might be utilized as a quantitative PD biomarker in both tumors and surrogate tissues, such as skin and hair follicles, in human clinical trials. http://www.molecular-cancer.com/content/8/1/34 Shinji Mizuarai Kazunori Yamanaka Hiraku Itadani Tsuyoshi Arai Toshihide Nishibata Hiroshi Hirai Hidehito Kotani Molecular Cancer 2009, 8:34 2009-06-08T00:00:00Z doi:10.1186/1476-4598-8-34 Molecular Cancer 1476-4598 8 34 2009-06-08T00:00:00Z XML