Common tcr-Beta chain rearrangements in short-term cultured lymphocytes infiltrating ovarian-tumors

We have recently reported that tumor reactive T cell lines and clones can be developed from lymphocytes infiltrating ovarian malignant tumors and ascites (TIL/TAL). These cells are currently used for immunotherapy of ovarian cancer. In this study we investigated the presence of common non-germline rearrangements at TCR Cbeta1 among freshly isolated and cultured ovarian TIL/TAL. The cultured ovarian TIL/TAL show a characteristic T cell phenotype (>95% CD3+) and mediate tumor target lysis. Our results show that non-germline rearrangements can be detected in cultured ovarian TAL isolated from ascites but not in freshly isolated TAL. Certain of rearranged bands were common among cultured TAL. In contrast, in samples of freshly isolated TIL from solid ovarian tumors localized at different organ sites, common rearrangements were found among fresh and cultured TIL. The results suggest that the observed polyclonality of T cells isolated from freshly collected ascitic tumors may be due, at least in part, to either dilution by passenger lymphocytes, or the lack of an in vivo oligoclonal response to autologous tumor, and indicate the usefulness of molecular analysis of TCR V gene segments in T cells used for immunotherapy.

Malignant CD5 B cells--biased immunoglobulin variable gene usage and autoantibody production

Malignant CD5 B cells obtained from patients with chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) were analyzed for immunoglobulin variable gene usage, CD5 gene expression and autoantibody production. A statistically significant biased usage of the VH5, VH6 and VKIII immunoglobulin variable gene families was observed. It is important to point out that both VH5 and VH6 are extremely small families which are located at the 3' extremity of the immunoglobulin variable gene locus. We determined that the transcription of the CD5 gene in T cell malignancies, CLL, SLL and a selected group of EBV transformed lines was identical. Autoantibody production was studied in a panel of heterohybridomas obtained by the fusion of CLL cells with mouse myeloma line SP2/0. A large fraction of these heterohybridomas secrete autoantibodies; some were monospecific, some bispecific and some polyspecific.

Multiple small exposures of filtered mid-UV radiation increase the resistance of Chinese hamster cells to far-UV, mid-UV and filtered mid-UV radiation

The response of Chinese hamster cells (V79-MI2G) to multiple, low doses of filtered mid-UV radiation (wavelengths longer than 300 nm) were examined over an exposure period of 30 days. Cell survival and the induction of mutation at the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) locus using resistance to 6-thioguanine (TG) were the endpoints in this study. With increasing total accumulated dose given at 500 J/m2/day as a single short exposure, an increased resistance to cell killing was observed. This increase in resistance to cell killing was accompanied by a gradual decrease in sensitivity to the induction of mutants resistant to 6-TG. Above total accumulated doses of 5000 J/m2 the frequency of 6-TG resistance did not increase. After multiple doses of filtered mid-UV radiation the cells became more resistant to subsequent challenges with acute doses of far-UV, mid-UV or filtered mid-UV. The increased resistance to the cell killing action and to the mutation induction by UV suggests that during exposure to low, multiple doses of filtered mid-UV radiation the cells become adapted to the damaging effects of filtered mid-UV radiation.

Nutritional and hormonal regulation of the activity state of hepatic branched-chain alpha-keto acid dehydrogenase complex

The hepatic branched-chain alpha-keto acid dehydrogenase complex plays an important role in regulating branched-chain amino acid levels. These compounds are essential for protein synthesis but are toxic if present in excess. When dietary protein is deficient, the hepatic enzyme is present in the inactive, phosphorylated state to allow conservation of branched-chain amino acids for protein synthesis. When dietary protein is excessive, the enzyme is in the active, dephosphorylated state to commit the excess branched-chain amino acids to degradation. Inhibition of protein synthesis by cycloheximide, even when the animal is starving for protein, results in activation of the hepatic branched-chain alpha-keto acid dehydrogenase complex to prevent accumulation of branched-chain amino acids. Likewise, the increase in branched-chain amino acids caused by body wasting during starvation and uncontrolled diabetes is blunted by activation of the hepatic branched-chain alpha-keto acid dehydrogenase complex. The activity state of the hepatic branched-chain alpha-keto acid dehydrogenase complex is regulated in the short term by the concentration of branched-chain alpha-keto acids (inhibitors of branched-chain alpha-keto acid dehydrogenase kinase) and in the long term by alteration in the total branched chain alpha-keto acid dehydrogenase kinase activity.

Promoter-enhanced neoplastic transformation after gamma-ray exposure at 10 cGy/day

We have measured gamma-ray-induced neoplastic transformation in C3H10T1/2 mouse embryo cells irradiated at an average 10 cGy/day throughout the useful life span of these cells for transformation studies. At cumulative total doses of 50, 150, 300, and 450 cGy, samples of cells were assayed for cell survival and neoplastic transformation with or without the administration of 0.1 micrograms/ml of 12-O-tetradecanoylphorbol-13-acetate (TPA) starting 24 h after the irradiation. The results indicate that, at a dose rate of 10 cGy/day, the rate of induction of neoplastic transformation is reduced by a factor of thirteen compared to that at 100 cGy/min. Still, frequencies above the background level are observed. These results are consistent with previous data which, at 144 cGy/day (0.1 cGy/min), showed that radiation-induced initiation events could be repaired during exposure, thus reducing the frequency of transformation from that observed at 100 cGy/min [A. Han et al., Cancer Res. 40, 3328-3332 (1980)]. Although the addition of TPA after the delivery of a particular dose at 10 cGy/day produced a significant increase in the frequency of neoplastic transformation, the degree of enhancement was less than after higher-dose-rate exposures [C.K. Hill et al., Radiat. Res. 109, 347-351 (1987)]. These results indicate that during 7 weeks of exposure, the repair of radiation-induced initiation was extensive but not complete, and suggest that a significant part of the damage persists which can be promoted by TPA. These observations support the inference that initiation and promotion are not tightly coupled and are probably independent processes.

Multiple, small exposures of far-ultraviolet or mid-ultraviolet light change the sensitivity to acute ultraviolet exposures measured by cell lethality and mutagenesis in V79 Chinese hamster cells

Chinese hamster V79 cells (subline MI2G) were exposed repeatedly to fractionated doses of germicidal 254 nm light (far-uv) at 6 J.m-2/fraction/day or sunlight-simulating 290-330 nm (mid-uv) at 150 J.m-2/fraction/day and sensitivities to cell killing action and mutation of far-uv and mid-uv were examined. As the number of exposure fractions increased, the cell cultures became resistant to cell killing induced by both far-uv and mid-uv. Increases in both Do and Dq were observed. Treatment with exposures of 6 J.m-2 far-uv is more efficient in yielding cell cultures that are resistant than exposures of 150 J.m-2 mid-uv. In contrast to the cells exposed to repeated far-uv, the cells exposed to repeated mid-uv were relatively more resistant to cell killing effects of mid-uv than far-uv, suggesting a possible role of photolesions other than pyrimidine dimers. When mutants resistant to 6-thioguanine were assayed during repeated exposure to far- or mid-uv light, the yield was initially linear with accumulating dose. At high total accumulated doses, the frequency decreased gradually (6 J.m-2 mid-uv) or reached a plateau (150 J.m-2 mid-uv). The sensitivity of N80 cells (exposed to 80 fractions of mid-uv) to mutation induction by uv light is higher than that of the original MI2G cells, whereas U81 cells (exposed to 81 fractions of far-uv) have a sensitivity similar to that of the original cells. Although an initial decrease in resistance to cell killing was observed, resistant cells retained their characteristics after 100 days in culture without further exposure. Cross-resistance to X rays was not shown. The data in this paper suggest that the capacity for repair of photolesions in DNA by repair processes was enhanced in cell cultures by repeated exposure to far-uv or mid-uv and that this altered the cells' ability to cope with lethal and mutagenic lesions. It remains to be seen if these changes in cell sensitivity were brought about by selective or inductive processes or a combination of both.

Promotion, dose rate, and repair processes in radiation-induced neoplastic transformation

C3H10T1/2 cells were exposed to low doses of 60Co gamma rays at 100 or 0.10 cGy/min and the incidence of neoplastic transformation was assayed with or without the addition of tetradecanoylphorbol-13-acetate (TPA). As we reported earlier [A. Han, C. K. Hill, and M. M. Elkind, Cancer Res. 40, 3328-3332 (1980); C. K. Hill, A. Han, F. Buonaguro, and M. M. Elkind, Carcinogenesis 5, 193-197 (1984)], the frequency of neoplastic transformation per unit dose following low doses appears to be linear and is reduced 2.3-fold at 0.10 cGy/min compared to 100 cGy/min. We report now that the addition of TPA 24 h after irradiation appreciably enhances the frequency after both low- and high-dose-rate exposures. The enhancement indicates that TPA leads to the expression of potentially effective, preneoplastic damage due to gamma rays. Our data suggest that the enhancement of transformation by TPA is essentially independent of dose rate. Also, our results suggest that the sector of preneoplastic damage which is repaired during protracted exposures becomes unavailable to enhancement by TPA.

Central metabolism of beta-endorphin in different species of temperature acclimated rodents

The purpose of this study was to characterize the central metabolism/processing of beta-endorphin in wild, desert rodents and to study the effect of heat and cold acclimation on central metabolism/processing and beta-endorphin half-life. This report suggests that a shift occurs in the processing of beta-endorphin in desert rodents acclimated to heat and cold leading to an accumulation of gamma-type endorphins. The data support a significant difference in beta-endorphin half-life between the rodents and the laboratory white rat.

Neoplastic transformation is enhanced by multiple low doses of fission-spectrum neutrons

The neoplastic transformation of C3H mouse 10T1/2 cells was measured induced by fission-spectrum neutrons delivered at a high dose rate in five fractions over 4 days. The transformation frequency was significantly enhanced over that due to single equivalent total doses. These new data, in the low dose region, demonstrate an increased transformation frequency by fractionated versus single exposures of high-dose-rate fission-spectrum neutrons; an increase equal to that observed with low-dose-rate fission-spectrum neutrons (i.e., 0.086 rad/min). Estimates of the dose modifying factor (DMF), based upon the ratio of the initial linear portions of the induction curves for high and for low dose rates, suggest the same DMF (approximately 7.8) for both five daily fractions of high-dose-rate neutrons and for low-dose-rate neutrons. However, when these results are compared to those following high-dose-rate 60Co gamma rays (100 rad/min), the relative biological effectiveness (RBE) for low-dose-rate fission-spectrum neutrons based upon slope ratios is 19.6; similarly, the RBE relative to five daily fractions of 60Co gamma rays is 78.8.

Differences in sensitivity between human, mouse and Chinese hamster cells to killing by monochromatic ultraviolet light

Irradiation of human (IMR-91), mouse (10T1/2) and Chinese hamster (V79) fibroblasts with monochromatic ultraviolet light (u.v.) in the far-, mid-, and near-u.v. regions resulted in cell-strain-specific changes in sensitivity as a function of the wavelength used. The data suggested cell-strain-specific action spectra for cell killing by ultraviolet light that did not correlate with the ability of examined cells to excise pyrimidine dimers.

Action spectra for killing and mutation of Chinese hamster cells exposed to mid- and near-ultraviolet monochromatic light

We have examined the response of Chinese hamster V79 cells to monochromatic light of selected wavelengths in the mid- to near-UV region, using cell survival and induction of mutants resistant to 6-thioguanine (6-TG) or ouabain (OUA) as end points. As the wavelength increased from 313 to 405 nm, the induction of mutants resistant to 6-TG and to OUA decreased to a greater degree than did cell survival. Cells resistant to OUA were induced with considerably lesser efficiency at wavelengths of 313 and 334 nm than cells resistant to 6-TG. No mutants resistant to either 6-TG or OUA were induced by 405-nm light, and no mutants resistant to OUA were induced by 365-nm light. Thus, cell killing and mutation induction have different action spectra, and furthermore, action spectra for mutation induction at the HGPRT and Na+/K+-ATPase loci are different from each other. These observations imply important differences in the cellular mechanisms, and/or lesions, for cell inactivation, induction of 6-TG and OUA resistance for V79 cells exposed to near-UV monochromatic light.

Repair processes and radiation quality in neoplastic transformation of mammalian cells

Appropriate in vitro mammalian cell systems facilitate the study of cellular mechanisms of radiation oncogenesis. C3H 10T1/2 cells derived from mouse embryo have been used to study the effects of protracted irradiation on cell killing and incidence of neoplastic transformation. Neoplastic transformation in these cells results in the appearance of colonies of densely piled up, disorganized cells that grow on top of the contact inhibited monolayer of nontransformed cells. Protracted exposures of 60Co gamma rays or fission-spectrum neutrons (from the JANUS reactor at the Argonne National Laboratory) were given either at low dose rates or as multifractionated regimens using high dose rates. Dose protraction of gamma rays by multifractionation at a high dose rate (50 rad/min) results in appreciable reduction in cell killing and also significantly reduces the incidence of neoplastic transformation. Irradiation at a low dose rate has the same qualitative effect. In contrast, protracted exposures of fission-spectrum neutrons, given at a low dose rate (0.086 or 0.43 rad/min), result in significant enhancement of the frequency of transformation in the dose region of up to 80 rad. However, the survival of cells is essentially the same as that for the same single dose of neutrons given at a high dose rate. These observations are consistent with net "error-free" repair of transformational damage following protracted exposure of a low LET radiation and possibly a net "error-prone" repair of transformational damage after protracted irradiations with fission-spectrum neutrons.

Fission-spectrum neutrons at a low dose rate enhance neoplastic transformation in the linear, low dose region (0-10 cGy)

The neoplastic transformation of C3H 10T1/2 cells induced by fission-spectrum neutrons delivered at a high dose rate is linear up to 40 cGy. Reducing the dose rate increases the frequency of transformation in the low dose region. At a dose rate of 0.086 cGy min-1, the initial part of the induction curve remains linear but it has a slope 9-fold greater than the initial part of the curve at a high dose rate.

Accumulation of unesterified arachidonic acid in ischemic canine myocardium. Relationship to a phosphatidylcholine deacylation-reacylation cycle and the depletion of membrane phospholipids

Studies in ischemic canine left ventricle have shown that the depletion of membrane phospholipids is a critical event in the development of a sarcolemmal calcium permeability defect and associated irreversible myocyte injury. The mechanism of phospholipid loss is unclear, but may be due to the activation of endogenous phospholipases. Since arachidonic acid is a fatty acid found almost entirely in phospholipid, increases in arachidonate provide evidence for increased phospholipase activity. The present study was designed to examine the temporal relationship of the accumulation of free arachidonate with the onset of phospholipid depletion during fixed ligation of the left anterior descending coronary artery in canine myocardium. The following results were demonstrated in ischemic canine myocardium: (1) the accumulation of unesterified arachidonate is minimal during 10-30 minutes of ischemia, but is significantly increased after prolonging the duration of ischemia to 1-3 hours; (2) significant increases in arachidonate precede the development of a significant decrease in total phospholipid content; (3) the decrease in the arachidonate content of phosphatidylcholine is accompanied by similar decreases in all of the fatty acyl moieties; (4) the arachidonate content of lysophosphatidylcholine and diacylglycerol are unchanged during myocardial ischemia; (5) there is evidence of a deacylation-reacylation cycle in phosphatidylcholine prior to the accumulation of free arachidonate; (6) the fatty acyl specificity of the lysophosphatidylcholine acyltransferase corresponds to the pattern of fatty acyl remodeling of phosphatidylcholine during early myocardial ischemia. These data suggest that the accumulation of arachidonate may be a more sensitive measure of phospholipid degradation than the decrease in total phospholipid content in ischemic canine myocardium. It is postulated that the defective reacylation of arachidonate into phosphatidylcholine may contribute to the net loss of membrane phospholipid during myocardial ischemia.

Multifractionation of 60Co gamma-rays reduces neoplastic transformation in vitro

Incidences of neoplastic transformation of 10T 1/2 cells, derived from a C3H mouse embryo, were measured following irradiation of cells with 60Co gamma-rays delivered in single total doses, from 25 to 300 rads, or in different numbers of fractions and with different time intervals between fractions. Throughout the range of total doses that was examined (25-300 rads) exposure of asynchronous, actively growing 10T 1/2 cells to a dose of gamma-rays in five equal daily fractions, rather than in a single exposure, results in a significant reduction in transformation frequency. The initial part of the induction curve fits a straight line quite well. The slope of the line for five daily fractions is approximately 3-fold less steep than that for single exposures. A further increase in the interfraction interval, to 48 h, or further reductions in the dose per fraction, led to additional decreases in the incidence of neoplastic transformation. Our observations are consistent with a net 'error-free' repair of subtransformation damage as a result of protracted irradiation with 60Co gamma-rays.

Repair of neoplastic transformation damage following protracted exposures to 60Co gamma-rays

The incidences of neoplastic transformation induced by 60Co gamma-rays in exponentially growing mouse embryo 10T1/2 cells were measured following acute and protracted exposures. Delivery of 60Co gamma-rays at a low dose rate (0.1, 0.5, 2.5 cGy min-1) compared with a high dose rate (100 cGy min-1) results in appreciable, dose rate dependent reductions in cell killing and, independent of the effect on cell survival, reduces significantly the incidence of neoplastic transformation. Exposure of exponentially growing 10T 1/2 cells to a dose of gamma-rays in 5 equal daily fractions also significantly reduces transformation frequency, compared with delivery in a single dose, throughout the dose range examined (25-300 cGy). The initial parts of the induction curves are fitted quite well by a linear dose dependence. The slopes of the regression lines for multifractionation delivery or irradiation at 0.1 cGy min-1, are one-third and one-half, respectively, of those for single exposures at a high dose rate. Increasing the inter-fraction interval up to 48 h, or reduction of the dose per fraction further reduce incidence of neoplastic transformation. We conclude that protracted exposures of low LET radiation result in a net "error-free" repair of subtransformation damage.

Possible error-prone repair of neoplastic transformation induced by fission-spectrum neutrons

We have examined the effect of fission-spectrum neutrons from the JANUS reactor at Argonne National Laboratory, delivered either as acute or protracted irradiation, on the incidence of neoplastic transformation in the C3H 10T1/2 mouse embryo cell line. Acute exposures were delivered at 10-38 cGy min-1, protracted exposures at 0.086 or 0.43 cGy min-1. The total doses for both ranged from 2.4 to 350 cGy. In the low dose region (2.4-80 cGy), there was a large enhancement in transformation frequency when the neutrons were delivered at the low dose rates compared with the high dose rates, but the survival of the cells was not significantly different between the two exposures conditions. Analysis of the initial parts of the curves shows that the regression line for protracted doses is about 9 times steeper than that for single acute exposures. Finally, the possibility is discussed that an "error-prone" repair process may be causing the enhanced transformation frequency by protracted neutron exposures.