Showing papers by "Cancer Research Institute published in 2006"

Neurofibromin plays a critical role in modulating osteoblast differentiation of mesenchymal stem/progenitor cells

Abstract: Mutations in the NF1 tumor suppressor gene cause neurofibromatosis type 1, a pandemic autosomal dominant genetic disorder with an incidence of 1:3000. Individuals with NF1 have a variety of malignant and non-malignant manifestations, including skeletal manifestations, such as osteoporosis, scoliosis and short statures. However, the mechanism(s) underlying the osseous manifestations in NF1 are poorly understood. In the present study, utilizing Nf1 haploinsufficient (+/-) mice, we demonstrate that Nf1+/- mesenchymal stem/progenitor cells (MSPC) have increased proliferation and colony forming unit-fibroblast (CFU-F) capacity compared with wild-type (WT) MSPC. Nf1+/- MSPC also have fewer senescent cells and have a significantly higher telomerase activity compared with WT MSPC. Nf1+/- MSPC have impaired osteoblast differentiation as determined by alkaline phosphatase staining, and confirmed by single CFU-F replating assays. The impaired osteoblast differentiation in Nf1+/- MSPC is consistent with the reduced expression of osteoblast markers at the mRNA level, including osteocalcin and osteonectin. Importantly, re-expression of the full-length NF1 GTPase activating related domain (NF1 GAP-related domain) is sufficient to restore the impaired osteoblast differentiation in Nf1+/- MSPC. Taken together, our results suggest that neurofibromin plays a crucial role in modulating MSPC differentiation into osteoblasts, and the defect in osteoblast differentiation may contribute at least in part to the osseous abnormalities seen in individuals with NF1.

Antiproliferative and Antiproteolytic activity of Pentoxifylline in cultures of B16F10 Melanoma cells

Abstract: Purpose: Pentoxifylline (PTX), a methyl xanthine derivative is widely used as a haemorheological agent in the treatment of peripheral vascular disease. In the present study, we investigated the in vitro effects of PTX on B16F10 melanoma cell proliferation, adhesion and secretion of Matrix metalloproteinases. Methods: The toxic range of PTX was evaluated using MTT test and colony formation assay. The cell cycle study of PTX treated cells was carried out using flow cytometric analysis. Adhesion assay of pretreated melanoma cells was carried out on extracellular matrix (ECM) substrates. The relative levels and activity of matrix metalloprotienase-9 (MMP-9) and MMP-2 were determined by gelatin zymography and western blotting. Results: Pentoxifylline significantly inhibited the in vitro proliferation of B16F10 cells in a concentration dependent manner and displayed an IC50 of 15.2 mM. Non-cytotoxic concentration of 1–3 mM of PTX for an exposure of 24 h demonstrated significant changes in cell morphology. A significant inhibition in G1-S phase transition was observed on PTX treatment. Pretreated F10 cells showed inhibition in adhesion to ECM components and markedly inhibited the secretion of MMP-9 and MMP-2 gelatinases. Conclusion: The results suggest that PTX even at non-toxic pharmacological concentrations acts as an effective antiproliferative agent with significant antiproteolytic and antiadhesive effects.

Mutational analysis of the cytoplasmic tail of jaagsiekte sheep retrovirus envelope protein.

Abstract: Jaagsiekte sheep retrovirus (JSRV) is the etiologic agent of a transmissible lung cancer in sheep, ovine pulmonary adenocarcinoma. JSRV is unique in that the envelope protein functions as an oncogene, since it can morphologically transform fibroblast and epithelial cells in culture and can induce lung tumors in mice. Previous studies indicated that the transmembrane (TM) protein is essential for transformation, and particular attention has focused on a YXXM motif in the cytoplasmic tail. In this study, we carried out systematic mutagenesis of the cytoplasmic tail of JSRV Env. Alanine scanning mutagenesis revealed four classes of mutants: mutants in which transformation was abrogated, those in which transformation was not affected, those with reduced transformation, and those with increased transformation (supertransformers). In general, the alanine mutations did not affect Env protein production or its localization to the plasma membrane. Three functional domains of the cytoplasmic tail were identified: an amphipathic helix at the N-terminal (juxtamembrane) side, a nonessential C-terminal region, and an internal region (including the YXXM motif) where mutations resulted in abrogation, decreases, or increases in transformation. Alanine mutations in the amphipathic helix in both the hydrophobic and hydrophilic faces generally abolished transformation. The mutation R591A showed partial transformation that was consistent with loss of signaling through the Akt-mTOR pathway and signaling predominantly through the Ras-Raf-MEK1/2-extracellular signal-regulated kinase 1/2 pathway. The supertransforming mutants generally showed increased signaling through Akt and reduced activation of p38 MAPK that is inhibitory for transformation. These mutants provide further insight into the role of the TM cytoplasmic tail in JSRV transformation.

Splenic metastases from cervical carcinoma: a case report.

Abstract: Splenic metastasis from squamous cell carcinoma of the uterine cervix is an unusual event in the natural history of the disease. The authors report one such uncommon occurrence in a 41-year-old female who presented initially with cervical carcinoma (stage IIB) and was treated with radical radiotherapy with concurrent weekly chemotherapy. Following a disease-free interval of less than a year, she developed hepatosplenic metastases despite being locally controlled. The literature relevant to the report is also discussed. This report reaffirms the notion that splenic metastases from cervical carcinoma are rare events but can occur as part of widespread dissemination.

HLA alleles in pre-menopausal breast cancer patients from western India.

Abstract: Background & objectives: Cytotoxic function of Natural Killer (NK) cells is regulated by the products of HLA class I genes. Associations between HLA alleles and risk for cancers have been suggested earlier. Several reports further emphasize the need to examine influence of HLA genotypes on risk for malignant disorders. Therefore, we undertook this study to assess the possibility of association of HLA-class I alleles in pre-menopausal breast cancer patients. Methods: Eighty one pre-menopausal breast cancer patients and 160, age and ethnicity matched healthy women from western India were studied. Genotyping for HLA class I alleles and HLAB*40 alleles (high resolution) was performed using genotyping kits from Genovision Inc., USA. Results: Nearly two-fold higher frequency of HLA - B*40 (16%) was observed in patients compared to controls (O.R. = 2.2; 95% C.I.-1.15-4.34; P<0.02). High resolution typing for HLA-B*40 alleles revealed predominance of HLA-B*4006 allele in both the study groups. Two other important observations relate to lower frequency of HLA - B*08 in patients and homozygosity at HLA-Cw locus in significantly higher proportion of patients. Interpretation & conclusion: The nature of peptides presented by HLA-B*4006 may have implications for higher frequency of HLA-B*40 in breast cancer patients. Higher frequency of homozygosity at HLA-Cw alleles in patients suggests a role for killer immunoglobulin-like receptors (KIRs) in NK cell mediated immune surveillance. Results of this study provide directions to further analyse role of immunogenetic mechanisms governing innate and adaptive immune responses contributing to modulation of risk for breast cancer.

The synergism between Belotecan and cisplatin in gastric cancer

Abstract: Purpose: We wanted to demonstrate the anti-cancer effect and interaction between belotecan and cisplatin on gastric cancer cell line and we evaluated the mechanisms of this synergistic effect in vitro. Materials and Methods: The growth inhibitory effect of belotocan and cisplatin against several gastric cancer cell lines (SNU-5, SNU-16 and SNU-601) was estimated by tetrazolium dye assay. The effect of a combination treatment was evaluated by the isobologram method. The biochemical mechanisms for the interaction between the drugs were analyzed by measuring the formation of DNA interstrand cross-links (ICLs) and DNA topo-I activity. Results: Belotecan showed synergism with cisplatin for growth inhibitory effect on the gastric cancer cell lines SNU-5, and SNU-16, but this was subadditive on the SNU- 601 cell line. The formation of DNA ICLs in SNU- 16 cells by cisplatin was increased by combination with belotecan, but this was not affected in SNU-601 cells. The topo-I inhibition by belotecan was enhanced at high concentrations of cisplatin in SNU-16, but not in SNU-601 cells. Conclusion: Belotecan and cisplatin show various combination effect against gastric cancer cells. The synergism between cisplatin and belotecan could be the result of one of the following mechanisms: the modulating effect of belotecan on the repair of cisplatin-induced DNA adducts and the enhancing effect of cisplatin on the belotecan-induced topo-I inhibitory effect. (Cancer Res Treat. 2006;38:159-167)

Cell Cycle Analysis by Flow and Laser-Scanning Cytometry

Abstract: Publisher Summary The cytometric methods for cell cycle analysis can be grouped into three categories. The first comprises methods that rely on a single time point measurement of the cell population. The second category is the methods that combine time-lapse measurements of populations of cells synchronized in the cycle or whose progression through the cycle was perturbed. Methods of the third category rely on analysis of DNA replication concurrent with measurement of DNA content. The time-lapse measurements of the cohort of 5’-bromo-2’-deoxyuridine (BrdUrd)-labeled cells allows one to estimate their rate of progression through different points of the cell cycle. Apoptotic cells often have fractional DNA content due to the fact that the fragmented (low MW) DNA undergoes extraction during the staining procedure. Some cells may also lose DNA (chromatin) by shedding apoptotic bodies. Only a fraction of DNA thus remains within apoptotic cells. The expression of proliferation-associated proteins often varies during the cell cycle, as well as is different in cycling and quiescent cells.

VEGF expression is inhibited by apigenin in human breast cancer cells

Abstract: Objective To study the effects of apigenin on vascular endothelial growth factor (VEGF) in human breast cancer cells (MDA-MB-231.

The journey of biospecimens: mortuaries to biorepositories.

Abstract: Our obsession for a sneak preview inside the causation and progression of cancer revolves around the study of tumours, normal tissues and body fluids and in current parlance all these are termed as ‘Biospecimens’. In the 19 century these biospecimens comprising of human parts and organs were provided by the mortuaries and museums; in the 20 century the biospecimens were paraffin embedded tissues and were provided by the pathology departments; and in the 21 century the ultimate provider of all biospecimens will be the organised world of ‘Biorepositories’. Diligent biospecimen providers kept pace with how the clinicians, pathologists and scientists of their era could best utilise these biospecimens, which to some extent depended on the technologies available to them. The naked eye examination of the cancer affliction of various organs during autopsy studies laid foundation to principles of cancer surgery and also resulted in the famous ‘Seed and Soil’ hypothesis on cancer metastasis by Paget in 1889. Substantial progress was then made with the power of microscopy that allowed detailed study of cellular and nuclear morphology by pathologists and resulted in the all important histological types and subtypes of cancer that we presently recognize. The biospecimen par excellence of the microscopy era were tumour and normal tissues chemically fixed and paraffin embedded and stored for decades. The merger of molecular and cell biology and the emerging ‘...omics’ technologies are now demanding a large number of biospecimens in the form of fresh or frozen tumour and normal tissues and body fluids. It is believed that as the microscope led to great knowledge of histological types and subtypes, the present technologies will utilise these biospecimens to understand and define molecular types and subtypes of cancer, validate new biomarkers and lay the foundation for pathway specific or targeted therapy.

A SLAMS dunk for cancer regulators.

Abstract: Genetic regulators of cancer are identified by combining data on global gene expression and DNA copy number.

Genotoxic Activity of Ambient Air Pollution in Three European Cities: Prague, Košice and Sofia: An 'In Vitro' Study

Abstract: Exposure of human hepatoma Hep G2 cells for two hours to extractable organic matter (EOM) adsorbed on respirable airborne particles <10 μm (PM10) resulted in a linear dose-dependent increase in DNA damage (p < 0.001). There were clear locationand season-related differences in ambient air genotoxicity based on the amount of EOM associated with PM10 per unit volume of air (EOM μg/m). These data were correlated with the concentrations of benzo[a]pyrene, carcinogenic polycyclic aromatic hydrocarbons (PAHs) and total PAHs per cubic meter of air. No dose-dependent increase in the oxidative DNA damage (8-oxodG or M1dG adducts) was detected in EOM-exposed cells.