Takeo Hasegawa

Increase in Tumor Oxygenation and Radiosensitivity Caused by Pentoxifylline

The effects of pentoxifylline (PTX), a drug commonly used for vascular disorders in humans, on the pO2 in SCK tumors of A/J mice and FSa-II tumors of C3Heb/FeJ mice as well as on the radioresponse of SCK tumors were investigated. When the host mice were injected intraperitoneally (ip) with 5 mg/kg PTX, the tumor pO2 increased slowly, peaked 20-50 min postinjection, and returned to its original level in 70-90 min. The magnitude of the increase in tumor pO2 varied markedly depending on the site and tumors. The magnitude of the changes in tumor pO2 after an ip injection of 25 or 50 mg/kg PTX was similar to that caused by 5 mg/kg PTX, but the pO2 tended to remain elevated longer with the higher dose of PTX. When the A/J mice bearing SCK tumors in the legs were injected ip with 50 mg/kg PTX and the tumors were X-irradiated 20 min later, the radiation-induced growth delay of the tumors was greater than that caused by X irradiation alone. The present study demonstrated that PTX is potentially useful for increasing the pO2 and the radioresponse of human tumors.

Antiangiogenesis therapy using a novel angiogenesis inhibitor, anginex, following radiation causes tumor growth delay

BackgroundThe present study investigated whether treatment with anginex, a novel antiangiogenic peptide, could block re-vascularization after radiation treatment.MethodsA squamous cell (SCCVII) xenograft tumor mouse model was employed to assess the effects of anginex given post-radiation on tumor growth, microvessel density (MVD), and oxygen levels. The oxygen status was determined by the partial pressure of O2.ResultsTumors in untreated mice increased threefold in 7.0 days, anginex-treated tumors (10 mg/kg intraperitoneal, twice) required 7.3 ± 0.9 days, and tumors exposed to 8-Gy radiation increased threefold over 11 days. Combination treatment of anginex and radiation caused the tumors to grow threefold in 16.1 ± 1.6 days, a delay which was significant and deemed supra-additive. Oxygen levels in tumors treated by stand-alone or combination therapies were significantly reduced; for example from 19.5 ± 4.9 mmHg in controls to 9.7 ± 1.9 mmHg in combination-treated, size-matched tumors. In addition, immunohistochemistry showed a decrease in MVD in the tumors treated with anginex, radiation, or the combination. These results suggest that a combination of anginex and radiation can greatly affect the amount of functional vasculature in tumors and prolong radiation-induced tumor regression.ConclusionAntiangiogenesis therapy with anginex, in addition to radiotherapy, will be useful by blocking angiogenesis-dependent regrowth of vessels.

Immune Activation and Radioprotection by Propolis

In this study, we focused on immune stimulation by Propolis, and examined changes in the effect of irradiation after Propolis administration. We also examined the radioprotective effect of Propolis by observing its effect on the immune system. The effect of immune activation by Propolis was investigated by measuring the total immunoglobulin (Ig) G and IgM. The radioprotective effect of immune activation by Propolis was investigated by measuring the T-lymphocyte subsets in the peripheral blood of mice following whole body irradiation. Compared with the control group, the IgG was significantly reduced in the Propolis group, indicating that Propolis suppressed IgG production. ELISA revealed that the amount of IgM in mouse serum was significantly higher in the Propolis group as compared with the control group, indicating that Propolis increased IgM production. The number of CD4-positive cells was increased only in the Propolis group. Likewise, the number of CD4-positive cells increased by 81% in the Propolis with irradiation group compared with the irradiation group alone. Compared with the control group, the Propolis group increased CD8-positive cells. Compared with the irradiation alone group, CD8-positive cells were decreased by Propolis with irradiation group. Propolis activated macrophages to stimulate interferon (IFN)-gamma production in association with the secondary activation of T-lymphocytes, resulting in a decrease in IgG and IgM production. Cytokines released from macrophages in mouse peripheral blood after Propolis administration activated helper T-cells to proliferate. In addition, activated macrophages in association with the secondary T-lymphocyte activation increased IFN-gamma production and stimulated proliferation of cytotoxic T-cells and suppressor T-cells, indicating the activation of cell-mediated immune responses.

Histopathological changes in rabbit uterus carcinoma after transcatheter arterial embolization using cisplatin

Abstract The effects of chemoembolization with cisplatin on gynecological malignancy were investigated using rabbit uterine tumors. A group of 20 rabbits were subjected to inoculation of the uterus with 5×107 VX2 carcinoma cells and 4 weeks later were divided into four groups, each consisting of five rabbits: an untreated control group, a group given cisplatin intraarterially (IA), a group subjected to transcatheter arterial embolization (TAE) with Gelfoam particles and a group subjected to transcatheter chemoembolization (TACE) with Gelfoam particles plus 1 mg/kg cisplatin. All groups were examined histologically 2 days after treatment. The untreated control group was further investigated 4 weeks after inoculation. In the untreated control group, the tumor cell nuclei varied in size and were irregular in form, and multiple nuclei and nuclear division were also observed. No necrotic zones were found up to 4 weeks after inoculation. The IA group showed no necrosis, but a few apoptotic cells were scattered throughout the tumor. In the TAE group, necrosis was observed in the center of the tumors, but proliferating cells persisted at the periphery. In the TACE group, necrosis was observed in the central part with many apoptotic cells surrounding the necrotic region in layers. The proliferating cell nuclear antigen (PCNA) index was 95.88% in the untreated control group, 86.6% in the IA group, and 8.62% in the TACE group, indicating a significant reduction in cell proliferation in the TACE group. These findings suggest that TACE results in more effective cytotoxicity than the other two treatments in uterine cancer tumor transplants.

Hydralazine at thermoradiotherapy: tumor size and blood flow effects.

PURPOSE This study was aimed to assess the dependence on tumor size and blood flow of the efficacy of a vasoactive drug hydralazine with thermoradiotherapy. METHODS AND MATERIALS Experiments were performed on mice bearing SCC-VII tumors with volumes of about 85 and 340 mm3 (7-8 or 11-12 days after transplantation, respectively). Local hyperthermia (water bath, 43 degrees C, 0.5 h) was started 3 h after irradiation of tumors. Hydralazine (2.5 mg/kg, IP) was given 0.5 h before heating. Tumor blood flow was evaluated by laser Doppler flowmetry before, during and up to 2 days after the treatments. RESULTS It was shown that hydralazine and hyperthermia, even in combination with each other, had very weak anti-tumor effect, especially for 85 mm tumors. The agents also insignificantly enhanced the efficacy of radiotherapy excluding the case of polyradiomodification for 340 mm3 tumors when a dose modifying factor of about 2.0 was achieved. Thermometry showed only a small improvement by HDZ in heating patterns of tumors of both sizes. Meanwhile, the therapeutic efficacy of hydralazine and heat was correlated with the changes in tumor blood flow, first of all with the delayed effects. The radiomodifiers induced only minor and transient suppression of perfusion in the smaller tumors, and more markedly and for longer time decreased blood flow in the larger tumors. In the latter case, the inhibiting effect of the drug plus hyperthermia remained for at least 48 h after the treatment. CONCLUSION (a) The combined use of hydralazine and heat seems to be advisable only at radiotherapy of rather large advanced tumors; (b) the efficacy of such radiomodification is correlated with prolonged inhibition of tumor blood flow by these agents; and (c) hydralazine and hyperthermia are likely to kill selectively both acutely and chronically hypoxic radioresistant cancer cells.

Enhancement of Hyperthermic Effects Using Rapid Heating

Although favorable results have been reported concerning hyperthermic treatment against malignant tumors, there are still problems such as thermometry, determination of heating region, and long treatment time. The present research, which was conducted on laboratory animals, confirmed that the antitumor effect is augmented when the temperature is rapidly increased to the target temperature, regardless of the length of hyperthermic treatment time after the target temperature has been reached. This result suggests that the time of hyperthermic treatment can be shortened. For the experiment, C3H mice were used after subcutaneously inoculating them with SCC-VII tumor in the thigh. Hyperthermic treatment was performed at 43°C and 44°C for 20 and 40min using a warm water bath and an RF heating device. Changes in tissue blood flow before and after heating, the rate of tumor growth after hyperthermic treatment, tissue denaturation by antibody tissue staining, cytokinetic activity, and apoptosis were examined in two groups: a rapid-heating group, in which the heating temperature was increased to the target temperature in 1 min, and a slow-heating group, in which the heating temperature was gradually increased to the target temperature over a period of 10min. Changes in blood flow were not observed in the slow-heating group before or after the hyperthermic treatment in normal tissue or tumor tissue. On the other hand, blood flow in normal tissue was observed to increase significantly in the rapid-heating group after heat treatment, whereas blood flow in tumor tissue was observed to decrease significantly after heat treatment. Tumor growth was significantly delayed in the RF-heating group compared with the warm water-heating group. Although the degree of delay in tumor growth was similar in the rapid-heating group (heating at 43°C for 20 min) and the slow-heating group (43°C for 40min), a strong antitumor effect was observed in the rapid-heating group, suggesting that tratment time could be shortened. Following each hyperthermic treatment, sections of extracted specimens were stained with PCNA antibodies. This method revealed a significant cytokinetic activity in the slow-heating group, suggesting that little damage was caused by heat. Induction of apoptosis, observed by APOTAG antibodies, was significant in the rapid-heating group, with a peak in programmed cell death at 6–12 h following the treatment. In addition, factor-8 antibody stain revealed reduced staining in the rapid-heating group, confirming vascular injury. These results suggested that rapid heating might augment the antitumor effect as well as shorten the time required for hyper-thermic treatment. Slow heating causes little vascular injury, maintains sufficient blood flow to provide ample oxygen and nutrition, and leaves recovery and biophylaxic action intact against injury caused by heat. On the other hand, it is thought that rapid heating can shorten the time required for hyperthermic treatment by incurring vascular disorder and thereby selectively causing fatal disorder in the tumor region.

Melanoma-Targeted Chemothermotherapy and In Situ Peptide Immunotherapy through HSP Production by Using Melanogenesis Substrate, NPrCAP, and Magnetite Nanoparticles

Exploitation of biological properties unique to cancer cells may provide a novel approach to overcome difficult challenges to the treatment of advanced melanoma. In order to develop melanoma-targeted chemothermoimmunotherapy, a melanogenesis substrate, N-propionyl-4-S-cysteaminylphenol (NPrCAP), sulfur-amine analogue of tyrosine, was conjugated with magnetite nanoparticles. NPrCAP was exploited from melanogenesis substrates, which are expected to be selectively incorporated into melanoma cells and produce highly reactive free radicals through reacting with tyrosinase, resulting in chemotherapeutic and immunotherapeutic effects by oxidative stress and apoptotic cell death. Magnetite nanoparticles were conjugated with NPrCAP to introduce thermotherapeutic and immunotherapeutic effects through nonapoptotic cell death and generation of heat shock protein (HSP) upon exposure to alternating magnetic field (AMF). During these therapeutic processes, NPrCAP was also expected to provide melanoma-targeted drug delivery system.

The use of a hypoxic cell radiosensitizer AK-2123 gave no improvement in thermoradiotherapy combined with hydralazine

An electron-affinic compound, AK-2123, and the anti-hypertensive agent, hydralazine, were combined with radiation and hyperthermia for treatment of murine SCC-VII tumours. Hydralazine markedly decreased tumour perfusion while AK-2123 had no influence on it. Hydralazine enhanced the tumouricidal effects of hyperthermia alone and in combination with radiation. AK-2123 provided a radiosensitization which was significant only in tumours irradiated without supplementary hyperthermia. The greatest tumour response was achieved when thermoradiotherapy was combined with hydralazine alone; the additional use of AK-2123 with this treatment combination did not further increase the effect. It is concluded that hydralazine plus heat virtually eliminated a hypoxia-related radioresistance in tumours, thus removing the requirement for AK-2123 administration.

Combined effects of radiation and ultrasound on ICR mice in the preimplantation stage

Embryos of ICR mice at the preimplantation stage of development were used to examine the single and combined effects of ultrasound (US) and radiation. Pregnant mice were exposed to a single dose of whole body gamma radiation and/or US at 2 hpc (hours postconception) or 3 hpc. The exposure duration was 10 min with 1-MHz continuous wave US at 1 or 2 W/cm(2) by I(SPTA) (intensities of spatial peak temporal average). Gamma irradiation of pregnant mice (2 hpc) was at 0.5 Gy at a dosage rate of 0.2 Gy/min. The rate for ultrasonic irradiation was a dose of 1 or 2 W/cm(2), considered by some to be too high in therapy, such as for arthritis in the rehabilitation area of the medical application. Various malformations were recognized, and the incidence of malformations in the 0.5-Gy exposure and the control groups were compared. A greater number of malformations were observed in the 0.5-Gy exposure group relative to the 0.5-Gy plus 1.0 W/cm(2) US exposure group. Therefore, the synergistic effects of radiation relate to external malformations, the number of implantations, and the rate of embryonic death due to US. It appears that US may act to repair DNA damaged by ionizing radiation. The cell cycle of the fertilized egg is delayed, which may be the mechanism by which lesions induced by ionizing radiation are healed by ultrasonic irradiation.

Transcatheter arterial embolization as a method of cisplatin-retention enhancement on the VX2 tumor uterus transplants

PurposeEnhanced cisplatin (Pt) retention using transcatheter arterial chemoembolization (TAE) with Gelfoam particles was studied in rabbit uterine tumors.MethodsTen rabbit uteri were inoculated with 5 X 107 cells of VX2 carcinoma. Three to four weeks later cisplatin, 1 mg/kg, was injected, either with (TAE group) or without (IA group) being mixed with small Gelfoam particles, into the aortic bifurcation over 5 s. Blood and tissue concentration of cisplatin were determined.ResultsSlower arterial blood clearance of Pt was observed in the TAE group compared with the IA group, whereas the venous blood Pt clearance curves were similar for both groups. The uterine tumor Pt concentration at 80 min was found to be 2.52-fold higher after TAE compared with LA (p < 0.01). In the pelvic metastatic lymph nodes, the Pt concentration was 4.63 times higher after TAE than after IA (p < 0.01).ConclusionThese data indicate that TAE is an effective means of increasing tissue concentration in uterine tumors.