Combined effects of hyperthermia, bleomycin, and X rays on Ehrlich ascites tumor

The combined effects of water-bath hyperthermia at 42.5 degrees C for 30 min, 1/10 LD50 Bleomycin iv, and 200 rad x irradiation were studied in DDD strain male mice with Ehrlich ascites tumor. The objective was to acquire data on the optimum regimen for a combined administration of these three modalities. The treatments were given 10 days after the inoculation of 2 X 10(6) of the cells into the right hind limb. Concomitant application of the three modalities led to an 80% regression. A single modality produced no significant effect and a 30-50% regression occurred when only two modalities were combined. To assess the influence of timing and sequence, hyperthermia was applied at 1, 2, 4, and 6 hr before, after, or simultaneously with the combination of Bleomycin and 200 rad X ray. A significant effect was obtained in the case of concomitant application of the three and hyperthermia was effective when applied within 2 hr before or after administration of Bleomycin plus irradiation. This enhancement disappeared at 4-hr intervals.     

The effects of hyperthermia on the cell cycle of Ehrlich ascites cancer cellsin vivo

The effects of hyperthermia on the cell cycle of Ehrlich ascites cancer cells were studied, and these effects simultaneously evaluated in terms of prolonging the survival of test mice inoculated with tumor cells from heat-treated mice. DDY mice bearing Ehrlich ascites cancer cells were placed in a water bath at 37°C, 39°C, 41°C, 32°C or 43°C. The heating of mice at 41°C, 42°C and 43°C induced the accumulation of cancer cells at the G₂M phase of the cell cycle with many cells exhibiting polyploidy (16C). The extent of accumulation increased as the temperature of incubation was raised, however the interrupted cell cycle resumed 120 hours after heating. The retransplantation of cells from the heat-treated mice revealed that the mice which were inoculated with Ehrlich ascites cancer cells from mice heated at 43°C survived longer, while the mice which were inoculated with Ehrlich ascites cancer cells from mice heated at 39°C survived for only a slightly shorter time than those which were inoculated with cells from mice heated at 37°C.     

The effects of hyperthermia on the cell cycle of Ehrlich ascites cancer cells in vivo

The effects of hyperthermia on the cell cycle of Ehrlich ascites cancer cells were studied, and these effects simultaneously evaluated in terms of prolonging the survival of test mice inoculated with tumor cells from heat-treated mice. DDY mice bearing Ehrlich ascites cancer cells were placed in a water bath at 37 degrees C, 39 degrees C, 41 degrees C, 42 degrees C. The heating of mice at 41 degrees C, 42 degrees C and 43 degrees C induced the accumulation of cancer cells at the G2M phase of the cell cycle with many cells exhibiting polyploidy (16 C). The extent of accumulation increased as the temperature of incubation was raised, however the interrupted cell cycle resumed 120 hours after heating. The retransplantation of cells from the heat-treated mice revealed that the mice which were inoculated with Ehrlich ascites cancer cells from mice heated at 43 degrees C survived longer, while the mice which were inoculated with Ehrlich ascites cancer cells from mice heated at 39 degrees C survived for only a slightly shorter time than those which were inoculated with cells from mice heated at 37 degrees C.     

Experimental studies on effects of total-body and local hyperthermia on metastases in mice

To study the effects of total-body hyperthermia (TBH) and local one (LH) on tumor metastases in animal experiments, heat was delivered to Lewis lung carcinoma (LLC)-bearing C57BL/6 mice and mouse ascites hepatoma-134 (MH-134)-bearing C3H/He mice, by water bath immersion systemically and locally. Rectal temperature in TBH was kept at 40 or 42 degrees C, while intratumor temperature in LH, at 40, 42, or 43 degrees C, respectively for 30 min. Also backgrounds of spread of lung metastasis of LLC in the case of TBH at 42 degrees C have been investigated as well as strategic preventive measures for it. The following results were obtained: The growth of primary LLC and MH-134 tumors was inhibited by TBH and LH at 42 degrees C and LH at 43 degrees C. The lung metastases of LLC increased by TBH at 42 degrees C. The lymph node metastases of MH-134 decreased by LH at 43 degrees C. The increase of lung metastases of LLC by 42 degrees C TBH occurred within 24hr after the session, presumably due to the increase in intravascular invasion of tumor cells and accelerated implantation of them according to histological changes of lungs. The observable tendency toward lung metastases continued for 48hr after treatment, coincidentally with distinctness in observation of histological changes. The increase mentioned above could be prevented by combined use of 42 degrees C TBH with anticancer drugs, as cis-diamminedichloroplatinum II or mitomycin-C. This combination resulted in further inhibition of tumor growth of primary LLC also, than non-combined 42 degrees C TBH. Considering the above facts, combined treatment of TBH with anticancer drugs is believed much valid clinically, in preventing metastases and making higher exertions of antitumor effects.     

Enhanced antitumor effects of bleomycin and moderate hyperthermia by additional use of ethanol

The combined effects of moderate local hyperthermia, bleomycin and ethanol were investigated with Lewis lung carcinoma tumors in female C57BL/6 mice. Different combinations of treatments were performed on days 4 and 7 after tumor implantation. Combined treatment of 41°C hyperthermia and bleomycin resulted in mild reductions of tumor growth. Hyperthermia plus bleomycin led to marked reduction in tumor growth under the condition of a 43°C temperature. The antitumor effects of 41°C hyperthermia combined with bleomycin were enhanced by the additional use of ethanol, and these effects were more remarkable than those of 43°C hyperthermia and bleomycin. A possible application of these findings to clinical therapy for advanced esophageal cancer was discussed.     

Enhanced antitumor effects of bleomycin and moderate hyperthermia by additional use of ethanol

The combined effects of moderate local hyperthermia, bleomycin and ethanol were investigated with Lewis lung carcinoma tumors in female C57BL/6 mice. Different combinations of treatments were performed on days 4 and 7 after tumor implantation. Combined treatment of 41 degrees C hyperthermia and bleomycin resulted in mild reductions of tumor growth. Hyperthermia plus bleomycin led to marked reduction in tumor growth under the condition of a 43 degrees C temperature. The antitumor effects of 41 degrees C hyperthermia combined with bleomycin were enhanced by the additional use of ethanol, and these effects were more remarkable than those of 43 degrees C hyperthermia and bleomycin. A possible application of these findings to clinical therapy for advanced esophageal cancer was discussed.     

Combined cell killing effects of anticancer drugs and hyperthermia in vitro

Using an in vitro colony forming assay system, cytotoxic effects of anticancer drugs, adriamycin (ADM) and peplomycin (PEP), and the combined effect of hyperthermia and anticancer drugs on cultivated KK-47 cells were investigated. From the response curves obtained at 42 and 43 degrees C hyperthermia, 20% growth inhibition time (IT20) at 42 and 43 degrees C hyperthermia and 50% growth inhibition time (IT50) at 43 degrees C were calculated. The IT20 and IT50 hyperthermia were combined with a 2-hour treatment of each of the anticancer drugs. When the hyperthermia was combined with various concentrations of ADM ranging from 0.005 to 0.1 microgram/ml, enhanced cell killing effects were obtained at the concentrations of less than 0.02 microgram/ml of ADM, whereas, there was no increase in cell killing effect at the concentrations of more than 0.05 microgram/ml of ADM. The combination of hyperthermia with PEP considerably enhanced the cell killing effects with an increase of PEP concentration.     

Experimental studies of the effects of local hyperthermia on blood flow, oxygen pressure and pH in tumors

The heat-induced environmental changes in tumor tissues are considered to influence the antitumor effect of hyperthermia or hyperthermochemotherapy, which is believed to complement the direct lethal effect of heat on tumor cells. The effects of local hyperthermia on the blood flow, oxygen pressure and pH in tissues were investigated using AH-100B tumor bearing rats, by immersing the tumor in a water bath at 41 degrees, 43 degrees and 45 degrees C. These parameters were measured in the marginal and deeper sites of the tumor mass, and in the normal muscle adjacent to the tumor. During immersion at 41 degrees C, blood flow in the tissue was increased at each site, and during immersion at 43 degrees C, tissue blood flow increased initially at each site, but decreased with time to rates below that of the unheated tissue. During immersion at 45 degrees C, the blood flow decreased markedly in each tissue. The changes in oxygen pressure and pH in each tissue were similar to those observed in the blood flow during localized heating at 41 degrees, 43 degrees and 45 degrees C. In local thermochemotherapy, the initial stage of hyperthermic treatment seems to be the most suitable time for administering carcinostatics, since it is the time when tumor blood flow has not yet decreased.     

Experimental studies of the effects of local hyperthermia on blood flow,oxygen pressure and pH in tumors

The heat-induced environmental changes in tumor tissues are considered to influence the antitumor effect of hyperthermia or hyperthermochemotherapy, which is believed to complement the direct lethal effect of heat on tumor cells. The effects of local hyperthermia on the blood flow, oxygen pressure and pH in tissues were investigated using AH-100B tumor bearing rats, by immersing the tumor in a water bath at 41°, 43° and 45°C. These parameters were measured in the marginal and deeper sites of the tumor mass, and in the normal muscle adjacent to the tumor. During immersion at 41°C, blood flow in the tissue was increased at each site, and during immersion at 43°C, tissue blood flow increased initially at each site, but decreased with time to rates below that of the unheated tissue. During immersion at 45°C, the blood flow decreased markedly in each tissue. The changes in oxygen pressure and pH in each tissue were similar to those observed in the blood flow during localized heating at 41°, 43° and 45°C. In local thermochemotherapy, the initial stage of hyperthermic treatment seems to be the most suitable time for administering carcinostatics, since it is the time when tumor blood flow has not yet decreased.     

Influence of differences in tumor vascularity upon the effects of hyperthermia

Summary Utilizing two types of human renal carcinoma heterotransplanted in nude mice, we investigated the variations in hyperthermic effects (42.5°C for 30 min) caused by differences in tumor type with special reference to variations in tumor vascularity. In the hypovascular JRC1 strain, sporadic vascular dilation was observed throughout the tumors after heating. Destruction of tumor cells was observed mainly in the region of dilation. In the hypervascular JRC11 strain, homogenous vascular dilation was observed immediately after heating, mainly at the periphery of tumors. There was a decrease in the viability of cells in the center of the tumor. Therefore, the hypervascular tumors showed greater destruction mainly at the center where blood circulation was reduced. The range of necrosis was also greatly affected by the extent of vascular dilation caused by heating in hypovascular tumors.     

An experimental study of enhanced cell killing by hyperthermia and bleomycin

Summary In vitro cell killing effects from heating and/or bleomycin have been investigated using the KK-47 cell line derived from a human bladder carcinoma and the colonyforming assay system. Percent survivals of the asynchronous cells heated to 40°, 41°, 42° and 43°C for 30 min were 96.6%, 93.3%, 91.4% and 71.2%, respectively, and those at 43° C for 2 h were 80.6%, 75.5%, 46.0% and 1.4%, respectively. The survival percentages of the cells treated with bleomycin at the concentrations of 1, 3, 6 and 10 g per ml at 37°C for 30 min were 66.0%, 40.4%, 21.9% and 11.9%, respectively. When hyperthermia at 43°C was combined with bleomycin, a greatly enhanced cell killing effect was obtained by preheating and simultaneous heating as compared with the effect of post-heating.     

Combination effects of CDDP and hyperthermia in mouse bladder tumor (MBT-2)

The combination effects of CDDP and hyperthermia in mouse bladder tumor (MBT-2) were investigated both in vivo and in vitro. MBT-2 was transplanted into the hind leg of a C3H/He mouse. Then the leg was dipped in a hot water bath immediately after the intraperitoneal administration of CDDP. The antitumor effects were evaluated from tumor volume. The CDDP plus hyperthermia (43 degrees C) group showed remarkable tumor growth retardation. The in vitro colony forming assay showed that MBT-2 cultured cells treated with CDDP at 42 degrees C exhibited great colony forming inhibition in comparison with the CDDP alone cells. The effects of CDDP plus hyperthermia on the cell cycle progression of MBT-2 cultured cells were studied by using flow cytometry. The results showed that the cells treated with CDDP at 42 degrees C exhibited an accumulation of cells in the C2 phase for many hours as compared with the CDDP alone cells, indicating thermal enhancement of DNA damage in MBT-2 cultured cells treated with CDDP.