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Incidence of human papillomavirus (HPV)-associated oral cancers is on the rise. However, epidemiological data of this subset of cancers are limited. Dental hospital poses a unique advantage in detection of HPV-positive oral malignancies. We assessed the utility of formalin-fixed paraffin-embedded (FFPE) tissues, which are readily available, for evaluation of high-risk HPV infection in oral cancer. For protocol standardization, we used 20 prospectively collected paired FFPE and fresh tissues of histopathologically confirmed oral cancer cases reported in Oral Medicine department of a dental hospital for comparative study. Only short PCRs (~ 200 bp) of DNA isolated using a modified xylene-free method displayed a concordant HPV result. For HPV analysis, we used additional 30 retrospectively collected FFPE tissues. DNA isolated from these specimens showed an overall 23.4% (11/47) HPV positivity with detection of HPV18. Comparison of HPV positivity from dental hospital FFPE specimens with overall HPV positivity of freshly collected oral cancer specimens (n = 55) from three cancer care hospitals of the same region showed notable difference (12.7%; 7/55). Further, cancer hospital specimens showed HPV16 positivity and displayed a characteristic difference in reported sub-sites and patient spectrum. Overall, using a xylene-free FFPE DNA isolation method clubbed with short amplicon PCR, we showed detection of HPV-positive oral cancer in dental hospitals. [ABSTRACT FROM AUTHOR]

The present investigation was undertaken to study the effect of in vitro exposure of Colo205, colonadenocarcinoma cells, to monocarboxylate transporter inhibitor α-cyano-4-hydroxycinnamate (αCHC) on cell survival and evolution of resistance to chemotherapeutic drug cisplatin. αCHC-treated Colo205 cells showed inhibition of survival accompanied by an augmented induction of apoptosis. Changes in cell survival properties were associated with alterations in lactate efflux, pH homeostasis, expression of glucose transporters, glucose uptake, HIF-1α, generation of nitric oxide, expression pattern of some key cell survival regulatory molecules: Bcl2, Bax, active caspase-3 and p53. Pretreatment of Colo205 cells with αCHC also altered their susceptibility to the cytotoxicity of cisplatin accompanied by altered expression of multidrug resistance regulating MDR1 and MRP1 genes. This study for the first time deciphers some of the key molecular events underlying modulation of cell survival of cancer cells of colorectal origin by αCHC and its contribution to chemosensitization against cisplatin. Thus these findings will be of immense help in further research for optimizing the use of αCHC for improving the chemotherapeutic efficacy of anticancer drugs like cisplatin. [ABSTRACT FROM AUTHOR]

In the present study using a transplantable murine T cell lymphoma designated as Dalton’s lymphoma, we investigated the role of oxygen, glucose and other environmental factors in evolution of altered survival responses in tumor cells during the late tumor-bearing stages. Tumor progression was observed to be associated with an improvement in the survival ability of tumor cells. Moreover, tumor serum and ascitic fluid obtained from the late tumor bearing stage was found to augment tumor cell survival in vitro, indicating that these humoral components of tumor bearing host contain factors capable of modulating tumor survival. Progressive tumor growth was also shown to be associated with depletion in glucose and oxygen content in the fluids of tumor microenvironment along with a concomitant augmentation in the production of lactate and lactate dehydrogenase. Moreover, tumor cells expressed higher amount of mRNA for inducible nitric oxide synthase, Hypoxia inducible factor-1 and 2 and Hsp70 and VEGF proteins during the late tumor bearing stages. Splenic macrophages and non-adherent splenic lymphocytes from tumor-bearing mice showed an increased production of IL-6, TGF-β, IFN-γ, IL-2R and VEGF during the late tumor-bearing stage, which could be implicated in the differential regulation of tumor growth in a tumor stage dependent manner. In conclusion, the observations of the present study suggest that factors contained in altered tumor microenvironment may act in concert to cause behavioral alterations in tumor cells, with respect to survival, during the course of the progression of a nonsolid T cell lymphoma. [ABSTRACT FROM AUTHOR]

It has been observed that the progressive ascitic growth of a transplantable T cell lymphoma of spontaneous origin, designated as Dalton's lymphoma (DL), induces inhibition of various immune responses and is associated with an involution of the thymus accompanied by a massive depletion of the cortical region and alteration in the distribution of thymocytes, with a decrease in CD4+CD8+, CD4+CD8- and CD4-CD8+ thymocytes. Morphological evaluation of thymocytes from DL-bearing mice revealed that with the progression of DL, a majority of thymocytes exhibited morphological features characteristic of apoptotic cell death, which included contracted cell bodies, condensed, uniformly circumscribed and densely stained chromatin, and membrane-bound apoptotic bodies containing one or more nuclear fragments. Quantitative and qualitative analysis of the DNA extracted from the thymocytes of DL-bearing mice revealed DNA fragmentation that increased concomitantly with the progression of DL and showed an oligonucleosomal DNA ladder pattern upon agarose gel electrophoresis, a hallmark of apoptotic cell death. Attempts to identify apoptotic factor(s) showed that the serum of DL-bearing mice contained certain soluble factor(s) that augmented the induction of apoptotis in thymocytes in a time- and dose-dependent manner. Although DL cells or their products, such as DL-cell-conditioned medium or DL-cell-free ascitic fluid, could also induce apoptosis of thymocytes in vitro, the magnitude of the same was consistently lower than that induced by the serum of DL-bearing mice. Further, elucidation of the mechanism of apoptosis induction in thymocytes with respect to the involvement of apoptosis-related genes revealed that the death pathway followed an interleukin-1 β-converting-enzyme-dependent, Fas-mediated apoptotic cascade, with a concomitant increase in the protein products of the bax, bad, p53, fas and fasL genes and cleavage of the 23-kD N-terminal fragment of Bcl-2 that exhibited Bax-like death effector properties. Copyright © 2000 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

Age-dependent tumor cytolytic functions of tumor-associated macrophages (TAM) obtained from mice bearing different stages of Dalton's lymphoma (DL), a spontaneous T cell lymphoma, were studied. Mice were separated into three groups on the basis of their reproductive status as indicator of age: young (prereproductive); adult (reproductive) and old (postreproductive). DL was injected (1 × 105 cells/mouse) intraperitoneally in mice; days 4, 10 and 16 from the day of injection were referred to as early, mid and late tumor stages, respectively. Normal peritoneal macrophages and macrophages isolated from the ascitic fluid of DL-bearing mice (TAM); 1 × 105 cells activated with lipopolysaccharide (LPS) plus interferon-γ (IFN-γ) and assayed for age-dependent alterations in macrophage tumoricidal functions such as: tumor cell binding, cytotoxicity, production of reactive nitrogen intermediates (RNI), expression of inducible nitric oxide synthase (iNOS) and oncostatin-M (OSM) were observed. TAM from old mice were observed to be inhibited with respect to tumor cell binding, cytotoxicity and expression of iNOS and OSM, as compared to macrophages of young and adult mice. TAM obtained from early tumor stages showed augmented tumor cytotoxicity as well as enhanced expression of iNOS and OSM in all the age groups. This effect was most pronounced in the TAM obtained from adult mice and least in the TAM obtained from old mice. The reasons for the observed difference are discussed. These observations should be helpful in understanding the effect of progressive tumor growth and age on the functions of TAM and their responsiveness towards therapeutic manipulations. [ABSTRACT FROM AUTHOR]

The effect of the ascitic growth of Dalton's lymphoma (DL), a T cell lymphoma, on the immune responses of the host mice to exogenous antigens, with respect to the humoral response, delayed-type hypersensitivity (DTH) response and the antigen-presenting ability of macrophages was investigated. The humoral immune response to sheep red blood cells (SRBC) as well as the antigen-presenting ability of macrophages (with keyhole limpet hemocyanin as the standard antigen) in the DL-bearing mice were consistently higher than in the normal mice, although the magnitude showed a decline during later tumor stages. However, the DTH response to SRBC was suppressed in the DL-bearing mice compared with the response in the normal mice. The possible mechanisms are discussed. In vivo administration of FK565, a synthetic biological response modifier, enhanced the humoral immune response as well as the antigen-presenting ability of the macrophages in the normal and early DL-bearing mice, whereas these immune responses n the later tumor-bearing animals were found to be nonresponsive to FK565 treatment. In contrast, the DTH response in the normal as well as in the DL-bearing mice was suppressed on FK565 administration. This is the first study of its kind regarding the effect of the ascitic growth of any T cell lymphoma on various aspects of the immune response to exogenous antigens and the correlation thereof with an immuno-modulator. Copyright © 1997 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]