Rong-Nian Shen

Whole-body hyperthermia decreases lung metastases in lung tumor-bearing mice, possibly via a mechanism involving natural killer cells

The effects of whole-body hyperthermia (WBH) on the course of the Lewis lung carcinoma (LLC) and B16 melanoma (B16) were examined. WBH was generated by microwave (2450 MHz) at an intraperitoneal temperature of 39.5–40.0°C and an intratumoral temperature of 40.0–40.5°C for 30 min once a week, ×3 (LLC) or ×6 (B16). The mice were sacrificed 21 days (LLC) or 42 days (B16) after tumor implantation and lung metastases were scored. Natural killer (NK)-cell activity was determined against the YAC-1 tumor target in WBH-treated tumorbearing mice as well as in tumor-bearing mice but untreated controls. The number of lung metastases was significantly reduced and NK-cell activity was higher in animals treated with WBH. Thus, this study suggests that WBH interferes with the spread of organ metastases, possibly through a mechanism involving NK cells.

A comparison of lung metastases and natural killer cell activity in daily fractions and weekly fractions of radiation therapy on murine B16a melanoma

C57BL/6J male mice were inoculated with 5 X 10(5) B16a melanoma cells. Seven days post-inoculation, when the tumor had grown to 8.0-10.0 mm in diameter, 120 tumor-bearing mice were randomly divided into three groups: (1) sham-irradiated controls, (2) mice receiving 200 cGy five times a week for 6 weeks, and (3) mice receiving 800 cGy once a week for 4 weeks. Thirty mice in each group were sacrificed 47 days postinoculation. Ten mice in each group were observed for the survival time data. The primary tumor was significantly smaller and the number of lung metastases were significantly fewer in mice treated with 800 cGy once a week compared to mice treated with 200 cGy five times a week. When natural killer (NK) cell activity was assessed against YAC-1 tumor targets, it was found to be significantly higher in mice treated with a single large weekly dose of irradiation. These results show that B16a melanoma responds more favorably to a single large dose of irradiation administered once a week compared to the smaller conventional fraction administered five times a week. This beneficial effect correlates with an increase in NK activity, indicating that there may be a causal relationship.

Clinical experience with hyperthermia in conjunction with radiation therapy.

The authors have reviewed the medical records of 421 sessions of hyperthermia treatments in 73 patients treated between 1987 and 1992 at the University Heights Cancer Center and the Indiana University Medical Center in Indianapolis, Ind. Temperatures attained during the course of therapy on each patient have been averaged and the results were evaluated for complete, partial, or no response. All patients had previously failed conventional radiation therapy, chemotherapy and surgery. Responses were defined as: (1) Complete response-lesions that completely disappeared during treatment and the response was sustained for a minimum of 6 months. (2) Partial response-lesions that underwent a reduction in size of greater than 50%. (3) No response-less than 50% reduction in tumor size during the course of treatment. Response varied somewhat according to histology and anatomical site of treatment; however, complete response was achieved in 45%, partial response in 48% (for an overall response of 93%), and no response in 7% of the patients. The response achieved varied with temperature attained and a minimum temperature of 40 degrees C for 40 min produced the greatest number of responses. Response to hyperthermia was directly related to the temperature achieved and the length of time the temperature was applied.

An Overview of the Role of Radiation Therapy and Hyperthermia in Treatment of Malignant Melanoma

From January, 1970 until December, 1987, a total of 188 malignant melanoma lesions in 92 patients were treated at the Department of Radiation Oncology, Indiana University Medical Center, Indianapolis, Indiana. Response was evaluated in 181 evaluable lesions treated by radiation alone and radiation plus hyperthermia to assess differences in response to a total dose, dose per fraction and overall time of treatment, as well as effects of adjunctive hyperthermia treatment. Different fractions of radiation, ranging from 100 cGy to 1000 cGy, were used. Local hyperthermia was administered for one hour following radiation treatment using microwave with different frequencies. The tumor temperature was also monitored during treatment. With a radiation dose of less than 400 cGy per fraction, and complete response rate (CR) was 34% (16/47) and the objective response rate (OR) was 62% (29/47). When hyperthermia was added, the complete response rate rose from 34% to 70%. With a dose of more than 400 cGy per fraction, the CR was 63% (48/77), and OR was 95% (73/77). When hyperthermia was added, the complete response rate rose from 63% to 77%.

A reliable method for quantitating chromatin fragments by flow cytometry to predict the effect of total body irradiation and hyperthermia on mice

The frequencies of chromatin fragments, including micronuclei, in murine thymus cells, spleen cells and bone marrow cells have been used as a quantitative indicator of gamma-ray induced chromosome damage and could be used to screen potential radioprotective agents as well. The yield of chromatin fragments induced in mice receiving different dosage levels of total body irradiation alone and in mice also given whole body hyperthermia as a potent radioprotector were assessed by flow cytometric analysis. Our results demonstrated that chromatin fragments induced by irradiation in vivo was clearly dose-dependent and that chromatin fragments could potentially serve as a biological indicator of radiation damage. One hour of whole body hyperthermia at 40 degrees C (+/- 0.2 degree C) given 20 hours before a lethal dosage (900 cGy) of total body irradiation protects 100% of DBA/2 mice from an LD 100/16 irradiation dose (dose of irradiation that killed 100% of the mice in 16 days). This is in good agreement with the percent of chromatin fragments formed in the cells of the protected animals, which showed no significant difference from those observed in the normal mice. The results indicate that whole body hyperthermia protected the thymus and bone marrow from irradiation damage. This study provides further evidence which supports that whole body hyperthermia can act as a potent radioprotector in vivo. Measurement of the frequencies of chromatin fragments by flow cytometry is simple and reliable. The method can be applied to screen radioprotective agents.

Micronuclei Assay — A Predictive Variable for Tumor Response to Treatment

Our preliminary data indicate that the formation of micronuclei (MN) in treated tumor cells is a predictive variable for tumor response to treatment. In a pilot study involving four patients who received both radiation therapy and hyperthermia, fine needle aspirate (FNA) samples were taken and analyzed before therapy, and after each 1000 centigray (cGy) up to 3000 cGy. The results indicate a correlation between increasing formation of micronuclei and decreasing tumor volume. All of the patients in this Study have had their tumors under control for at least one year. Our preliminary data demonstrated that a high level of micronuclei in tumor cells correlates with favorable response of the tumor to treatment with radiation and heat. The assay is easy to perform and FNA biopsy could be done in the clinic with minimal discomfort to the patient.

THE THERAPEUTIC EFFECT OF NATURIN-2 ON LEWIS LUNG CARCINOMA AND MURINE-AIDS

The immune system plays a major role in immuno-surveillance, and its impairment has been linked to cancer and immuno-deficiency disorders including AIDS. (1–3) The biological response modifier (BRM) is a term used for an agent whose antitumor effects were thought to be exerted through modulation of the host’s immune system, as contrasted with the antitumor effects of traditional chemotherapeutic drugs and irradiation which kill cancer cells directly. The BRMs are synthetic compounds or naturally occurring proteins that alter host immune responses and have been applied to a broad range of agents including cytokines. These cytokines include, but are not limited to, the interferons, the inter-leukins, the tumor necrosis factors, the hematopoietic colony stimulating factors, etc. More recent studies in our laboratory have demonstrated the potential of the interleukins and colony stimulating factors to decrease the metastatic potential of the B16 melanoma and the Lewis Lung Carcinoma and potential usefulness is that mice infected with the retrovirus (Friend Virus) can be rescued from death. This treatment was associated with restoration of immunosuppression and enhancement of immune function. The cytokines can act in greater than additive fashion and combinations of therapies are possible. (3–6)