Expansion and characterization of cells from surgically removed intervertebral disc fragments in xenogen-free medium

Low back pain due to degeneration of intervertebral disc (IVD) is a major health problem resulting insignificant disability as well as adding to the economic burden. Discectomy is a very common procedure doneworldwide to relieve this pain. At present all the surgically removed disc tissue is mostly discarded. However,there are reports that state that progenitor cells in the IVD can be grown ex vivo and have the potential to beused for IVD repair and regeneration. We report here that viable cells can be harvested from surgicallyremoved, herniated disc tissue and can be potentially used in cell based therapy. Further, we have successfullyreplaced xenogenic supplements such as foetal bovine serum with either autologous serum or human plateletlysate for culturing IVD cells from patient’s surgically removed disc tissue, without loss of any cell characteristics, including cell surface markers, growth factor secretion in the conditioned medium and osteogenic andchondrogenic differentiation potential in vitro. The present work will not only contribute to overcoming someof the major barriers in carrying out human clinical trials, but also provide a cheap, alternate source of proteinsand growth factors for growing IVD cells ex vivo for therapy

Human papillomavirus (HPV) genome status & cervical cancer outcome - A retrospective study.

Background & objectives: Persistent infections with high-risk (HR) human papillomaviruses such as HPV 16, 18, 31, 33 and 45 have been identified as the major aetiological factor for cervical cancer. The clinical outcome of the disease is often determined by viral factors such as viral load, physical status and oncogene expression. The aim of the present study was to evaluate the impact of such factors on clinical outcome in HPV16 positive, locally advanced cervical cancer cases. Methods: One hundred and thirty two pretreatment cervical tumour biopsies were selected from patients undergoing radiotherapy alone (n=63) or concomitant chemo-radiation (n=69). All the samples were positive for HPV 16. Quantitative real time-PCR was carried out to determine viral load and oncogene expression. Physical status of the virus was determined for all the samples by the ratio of E2copies/E7copies; while in 73 cases, the status was reanalyzed by more sensitive APOT (amplification of papillomavirus oncogene transcripts) assay. Univariate analysis of recurrence free survival was carried out using Kaplan-Meier method and for multivariate analysis the Cox proportional hazard model was used. Results: The median viral load was 19.4 (IQR, 1.9- 69.3), with viral integration observed in 86 per cent cases by combination of the two methodologies. Both univariate and multivariate analyses identified viral physical status as a good predictor of clinical outcome following radiation treatment, with episomal form being associated with increased recurrence free survival. Interpretation & conclusions: The present study results showed that viral physical status might act as an important prognostic factor in cervical cancer.

Novel inhibitor of DNA ligase IV with a promising cancer therapeutic potential.

Cancer is a dreaded disease where effective and cheap drugs are wanting. A large body of research is trying to identify anti-cancer molecules from nature, including plants, marine organisms, microorganisms, etc., and to ultimately synthesize promising molecules in the laboratory. Antibodies to tumour antigens/ receptors, microtubule inhibitors and DNA linking agents have been developed and used as drugs. Today the thrust is on identifying druggable molecules within the tumour cell. Small molecule inhibitors, targeted against crucial enzymes such as kinases, has led to the discovery of important anti-cancer drugs such as Glivec and Gefitinib. There is a great deal of interest in the development and use of therapeutics that target DNA repair pathways. Raghavan and his group chose Ligase IV as their target in the DNA repair pathway (Srivastava et al. 2012) Maintenance of genomic integrity is essential for cell homeostasis. Efficient repair of DNA damage ensures genomic stability. However, cancer therapies such as radiation and chemotherapy function by damaging genomic DNA, by specifically targeting rapidly dividing cancer cells, ultimately leading to cell death. Most of the cancer cells are repair-deficient, thereby providing a therapeutic opportunity to target DNA repair machinery. Although radiation and genotoxic drugs are initially effective in arresting tumour growth and reducing tumour burden, resistance and disease progression eventually occur. The resistance is acquired due to constant selection pressure by the therapeutics. Genetic mutations in the DNA repair genes are not only the initiating event in a cancer cell but also its limitation because the mutated gene function is often required by the cancer cell to maintain its own survival. This limitation has been exploited to specifically kill the tumour cells by targeting the mutated DNA repair gene while sparing the normal ones, a concept known as ‘synthetic lethality’ (Kaelin 2005). One of the main DNA damage repair pathways is double strand break (DSB) repair, which includes nonhomologous end joining (NHEJ) and homologous recombination (HR). It is plausible that targeting the molecular machinery driving the DNA damage repair (DDR), particularly NHEJ with small molecule inhibitors, will effectively enhance the efficacy of current cancer treatments that generate DNA damage and exploit synthetic lethal interactions. Radiation therapy and chemotherapy leads to DSB where NHEJ plays a major role in providing resistance to these agents in a cancer cell. The initial inhibitor L189 against Ligase I, III and IV reported in literature was non-specific (Chen et al. 2008). Raghavan and his group overcame this limitation by targeted design using specific docking of Ligase IV and comparing with L189 (Srivastava et al. 2012). The clever strategy led to the discovery of a novel specific inhibitor SCR7 for Ligase IV. Using elegant experiments on cell lines and mouse model the authors convincingly demonstrated that SCR7 was a specific Ligase IV inhibitor. SCR7 inhibits end joining of double strand breaks in diverse cell types resulting in tumour regression by activation of p53 mediated apoptosis (figure 1). Notably SCR7 treatment did not result in any adverse effects in mice and did not inhibit Ligase III. The authors have envisaged and addressed the likely limitations of SCR7 as a potential anti-cancer drug in humans and have proposed that cancer cells, due to their higher replication, high DNA damage rate and defective cell-cycle checkpoints, will be more sensitive to SCR7 compared to surrounding normal tissues (Srivastava et al. 2012). This may also reduce the possibility of resistance to SCR7. The therapeutic efficacy of SCR7 could be enhanced by specific delivery of SCR7 to the tumour tissue and as adjuvant cancer therapy.

Establishment & characterization of lymphoblastoid cell lines from patients with multiple primary neoplasms in the upper aero-digestive tract & healthy individuals.

Background & objectives: A major drawback for genetic studies as well as long-term genotype-phenotype correlation studies in cancer is lack of representative human cell lines providing a continuous source of basic biomolecules and a system to carry out various experimental investigations. This can be overcome to some extent by establishing lymphoblastoid cell lines (LCLs) by infecting peripheral blood lymphocytes with Epstein Barr virus (EBV) which is known to immortalize human resting B cells in vitro giving rise to actively proliferating B-lymphoblastoid cell lines. The present study involves preparation and characterization of LCLs generated from patients with multiple primary neoplasms (MPN) of upper aero-digestive tract (UADT). Methods: Thirty seven LCLs were established from UADT MPN patients and healthy age, sex and habit matched controls using EBV crude stock. Characterization was done with respect to expression of CD-19 (Pan B-cell marker), CD3 (T cell specific marker), CD56 (NK-cell specific marker), cell morphology, ploidy analysis, genotype and gene expression comparison with the parent lymphocytes. Results: LCLs showed rosette morphology with doubling time of approximately 24 h. Ploidy analysis showed diploid DNA content which was maintained for at least 30 population doublings. When compared with parent lymphocytes there appeared no change at genetic and gene expression level. Interpretation & conclusions: Our results show that lymphoblastoid cell lines are a good surrogate of isolated lymphocytes bearing their close resemblance at genetic and phenotypic level to parent lymphocytes and are a valuable resource for understanding genotype-phenotype interactions.

Effect of suicide gene therapy in combination with immunotherapy on antitumour immune response & tumour regression in a xenograft mouse model for head & neck squamous cell carcinoma.

Background & objectives: Prodrug activation strategy as well as immunotherapy have been widely used for cancer gene therapy. In the present study, using a head and neck squamous cell carcinoma (HNSCC) xenograft nude mouse model, we have investigated whether the two therapies in combination could improve tumour cell kill. We also investigated induction of immune effector cells viz., NK (DX5+) and DC (CD11c+) in vivo, post-combination gene therapy. Methods: A retroviral vector producing cell line (PLTK47.1 VPC) carrying Herpes simplex virus thymidine kinase gene (HSVtk) was used for intratumoural injection into NT8e xenograft tumours followed by the prodrug ganciclovir (GCV). IL-2 plasmid DNA was injected intramuscularly. Immune cells were analyzed by flow-cytometry. Non parametric ANOVA was performed with Kruskal Wallis test. Results: IL-2 could induce proliferation of both NK cells (DX5+) and dendritic cells (CD11c+) in vivo. Apoptosis was higher in combination therapy group as compared to HSVtk/GCV alone or IL-2 alone and was mediated through caspase-3 dependent pathway. Significant reduction in tumour volume was seen in all 3 treatment arms as compared to controls. Interpretation & conclusions: Combination of suicide gene therapy and immunotherapy leads to successful tumour regression in a HNSCC xenograft mouse model. Immunotherapy could help in a systemic long lived anti-tumour immune response which would prove powerful for the treatment of metastatic cancers, and also for minimal residual disease. The results of this study may form the basis for Phase 1 clinical trials.

Genotype, phenotype and cancer: role of low penetrance genes and environment in tumour susceptibility.

Role of heredity and lifestyle in sporadic cancers is well documented. Here we focus on the influence of low penetrance genes and habits, with emphasis on tobacco habit in causing head and neck cancers. Role of such gene-environment interaction can be well studied in individuals with multiple primary cancers. Thus such a biological model may elucidate that cancer causation is not solely due to genetic determinism but also significantly relies on lifestyle of the individual.

Comparison of the activities of wild type and mutant enhancing factor/mouse secretory phospholipase A2 proteins.

Enhancing factor (EF) protein, an isoform of secretory phospholipase A2 (PLA2), was purified as a modulator of epidermal growth factor from the small intestine of the Balb/c mouse. It was for the first time that a growth modulatory property of sPLA2 was demonstrated. Deletion mutation analysis of EF cDNA carried out in our laboratory showed that enhancing activity and phospholipase activity are two separate activities that reside in the same molecule. In order to study the specific amino acids involved in each of these activities, two site-directed mutants of EF were made and expressed in vitro. Comparison of enhancing activity as well as phospholipase A2 activity of these mutant proteins with that of wild type protein helped in identification of some of the residues important for both the activities

Heparin inhibits enhancing factor/phospholipase A2 activity and its binding to the cell surface.

Enhancing factor (EF), a mouse intestinal phospholipase A2 (PLA2), has been isolated and characterized. EF increases the binding of epidermal growth factor (EGF) to A431 cells almost two-fold by interacting with EGF. EF binds to a 100 kDa cell surface receptor and brings about an increase in the binding of EGF. In the present study we demonstrate that EF is a heparin binding protein and at the time of iodination of EF, the heparin binding site of EF has to be protected. Heparin inhibits the enhancing activity of EF as well as the binding of labelled EF to A431 cells. Inhibition of binding of EF to cells by heparin indicates that heparin binding region forms at least part of the receptor binding domain. These data suggest that the receptor for EF on the cell surface could be a heparin sulphate proteoglycan.

Trace amounts of enhancing factor/phospholipase A2 in mouse peritoneal exudate cells.

Enhancing factor (EF), a mouse phospholipase A2 (PLA2), has been purified from the small intestines, based on its ability to increase the binding of epidermal growth factor in a radioreceptor assay. EF/PLA2 was found to be localized predominantly in the Paneth cells in the small intestines. Whether mouse intestinal EF/PLA2 is identical/similar to mouse secretory PLA2 was to be determined. Phospholipases are known to play a crucial role in the process of inflammation. This paper reports the presence of trace amounts of EF/PLA2 in the peritoneal exudate cells. Western blot analysis of the acid extracts showed the presence of a 14 kDa immunologically cross-reactive protein. RT-PCR analysis using EF specific primers amplified a ~ 700 bp product which was further confirmed to be EF-specific by nested PCR analysis and sequencing. Presence of EF in the peritoneal exudate cells could be a unique mode of transport of growth factor modulator to the site of injury to aid in regeneration/cell proliferation of damaged tissue.