Taisuke Inomata

Tamoxifen-induced fatty liver in patients with breast cancer

Tamoxifen is an antioestrogenic agent used worldwide as an adjuvant therapy against breast cancer. Because it has both oestrogenic and antioestrogenic effects, it can induce lipid metabolism dysfunction. Louis and colleagues reported severe lipaemia induced by tamoxifen, but, to our knowledge, there has been no report of fatty liver as a result of exposure to tamoxifen. We have carried out abdominal computed-tomography (CT) examinations annually for all patients with breast cancer in the past 8 years. 24 (36·4%) (mean age 48·7 years) of 66 patients (mean age 49·6 years) who are receiving or have received oral tamoxifen (40 mg daily) for 3–5 years showed fatty changes of the liver diagnosed on annual CT examinations. For example, a 49-year-old woman with breast cancer who had received oral tamoxifen for 1 year had severe fatty liver of 15 HU (Housfield Unit) on abdominal CT scan (figure). The criteria used for diagnosing fatty liver was the ratio of CT value (liver/spleen) less than 0·9. The onset of fatty liver was observed at 1–44 months (mean 18 months) after the start of tamoxifen intake. The area of fatty changes of liver usually progressed from focal to diffuse. The changes disappeared between 1 and 14 months after termination of tamoxifen treatment. 11 of the 24 patients showed increases in liver enzymes (aspartate aminotransferase, alanine aminotransferase, and/or -glutamyl transpeptidase), four showed rises of total cholesterol, and another nine patients showed no abnormality. Abnormalities were seen earlier on CT examination than in laboratory data. In the 24 patients with fatty liver, two showed weight gain more than 10 kg after the start of tamoxifen intake, and other patients showed no obvious changes in their bodyweight. Since severe fatty liver is related to liver cirrhosis, attention to changes in liver function is crucial. Regular CT examination, ultrasonography, or both may be needed to monitor fatty changes of the liver and to rule out liver metastasis from breast cancer during tamoxifen treatment.

New antimetastatic hypoxic cell radiosensitizers: Design, synthesis, and biological activities of 2-nitroimidazole-acetamide, TX-1877, and its analogues

We designed, based on the molecular orbital (MO) calculation, synthesized, and evaluated the biological activities of the new antimetastatic hypoxic cell radiosensitizer, 2-nitroimidazole-acetamide, TX-1877, and its analogues. Each analogue has an electron-affinic imidazole group, an acetamide group and a certain hydrophilic group to control its biological effect, toxicity, and pharmacokinetics. In in vitro radiosensitization assay, most TX-1877 analogues, which have an electron affinity (EA) of more than 0.9 eV and partition coefficient (P) of more than 0.021, showed satisfactory enhancement ratios (ER > 1.60) at doses of I mM. On the other hand, imidazole analogues, such as TX-1908 (EA = 0.67 eV), TX-1910 (EA = -0.34 eV) and TX-1931 (EA = -0.37 eV), which have low electron affinities, had an ER of 1.31 or less. TX-1877 and KIN-806 effectively inhibited tumor regrowth when administered with irradiation in vivo at a dose of 0.4 mg/g. Tumor lung metastasis was inhibited by treatment with either TX-1877 or KIN-806 without irradiation at a dose of 0.4 mg/g. TX-1877 reduced markedly the mean number of metastatic lung nodules in comparison with KIN-806. Moreover, TX-1877 and KIN-806 enhanced macrophage and helper T lymphocyte infiltration for 3 weeks after drug treatment. TX-1877 shows a high EA value and has the C2 of HOMO localizing on N-methylamide and the C2 of LUMO localizing on 2-nitroimidazole group. The MO data might be useful for designing a bifunctional hypoxic cell radiosensitizer. TX-1877 and its analogues are potential antimetastatic hypoxic cell radiosensitizers, which would improve the efficiency of radiotherapy and quality of life in cancer treatment.

A 10-year experience of intraoperative radiotherapy for gastric carcinoma and a new surgical method of creating a wider irradiation field for cases of total gastrectomy patients

PURPOSE To improve the prognosis of gastric cancer, radical surgical resection with extensive lymph node dissection plus intraoperative radiation therapy (IORT) was tried in our clinic. In addition, a new operative procedure was created to obtain wider irradiation field for total gastrectomy patients. METHODS AND MATERIALS A total of 183 gastric cancer patients who underwent radical gastrectomy with or without IORT from August 1983 to July 1992 were retrospectively evaluated. The patients were divided into two groups: group 1 consisted of 58 patients who underwent radical operation plus IORT. A single dose of 28 to 30 Gy was delivered around the celiac axis with an electron beam of 12 MeV. Group 2, our historical control group, which showed no difference in age, sex and stage, consisted of 120 patients who underwent only radical surgery. In addition, a new method of total gastrectomy with IORT after mobilization of the tail and body of the pancreas was devised to get wider irradiation field for advanced gastric cancer. RESULTS Of the Stage II gastric cancer patients, all the 11 patients of group 1 are alive, whereas in group 2, the 4-year and the 8-year survival rates were 60% and 48%, respectively. In Stage III patients, the 8-year survival rate of group 1 was 55% vs. 35% in group 2. As for Stage IV patients, the 5-year survival rate of group 1 was 12% and that of group 2 was 13%. CONCLUSION Using this combined treatment modality of radical surgical operation+IORT, improved survival rates were obtained for Stage II and III gastric cancer patients. However, the method was ineffective for more advanced, Stage IV, patients. The wider irradiation field method used for total gastrectomy patients was safe and no complications were encountered.

Pifithrin-μ, an Inhibitor of Heat-Shock Protein 70, Can Increase the Antitumor Effects of Hyperthermia Against Human Prostate Cancer Cells

Hyperthermia (HT) improves the efficacy of anti-cancer radiotherapy and chemotherapy. However, HT also inevitably evokes stress responses and increases the expression of heat-shock proteins (HSPs) in cancer cells. Among the HSPs, HSP70 is known as a pro-survival protein. In this study, we investigated the sensitizing effect of pifithrin (PFT)-μ, a small molecule inhibitor of HSP70, when three human prostate cancer cell lines (LNCaP, PC-3, and DU-145) were treated with HT (43°C for 2 h). All cell lines constitutively expressed HSP70, and HT further increased its expression in LNCaP and DU-145. Knockdown of HSP70 with RNA interference decreased the viability and colony-forming ability of cancer cells. PFT-μ decreased the viabilities of all cell lines at one-tenth the dose of Quercetin, a well-known HSP inhibitor. The combination therapy with suboptimal doses of PFT-μ and HT decreased the viability of cancer cells most effectively when PFT-μ was added immediately before HT, and this combination effect was abolished by pre-knockdown of HSP70, suggesting that the effect was mediated via HSP70 inhibition. The combination therapy induced cell death, partially caspase-dependent, and decreased proliferating cancer cells, with decreased expression of c-Myc and cyclin D1 and increased expression of p21WAF1/Cip, indicating arrest of cell growth. Additionally, the combination therapy significantly decreased the colony-forming ability of cancer cells compared to therapy with either alone. Furthermore, in a xenograft mouse model, the combination therapy significantly inhibited PC-3 tumor growth. These findings suggest that PFT-μ can effectively enhance HT-induced antitumor effects via HSP70 inhibition by inducing cell death and arrest of cell growth, and that PFT-μ is a promising agent for use in combination with HT to treat prostate cancer.

Bevacizumab Treatment for Symptomatic Radiation Necrosis Diagnosed by Amino Acid PET

Bevacizumab is effective in treating radiation necrosis; however, radiation necrosis was not definitively diagnosed in most previous reports. Here we used amino acid positron emission tomography to diagnose radiation necrosis for the application of bevacizumab in treating progressive radiation necrosis. Lesion/normal tissue ratios of <2.5 on (18)fluoride-labeled boronophenylalanine-positron emission tomography were defined as an indication of effective bevacizumab treatment. Thirteen patients were treated with bevacizumab at a dose of 5 mg/kg every 2 weeks. Two patients were excluded because of adverse events. The median reduction rate in perilesional edema was 65.5%. Karnofsky performance status improved in six patients after bevacizumab treatment. Lesion/normal tissue ratios on (18)fluoride-labeled boronophenylalanine-positron emission tomography (P = 0.0084) and improvement in Karnofsky performance status after bevacizumab treatment (P = 0.0228) were significantly associated with reduced rates of perilesional edema. Thus, (18)fluoride-labeled boronophenylalanine-positron emission tomography could be useful for diagnosing radiation necrosis and predicting the efficacy of bevacizumab in progressive radiation necrosis.

Changes in the Ki-67 Labeling Rates of Head and Neck Squamous Cell Carcinomas during Preoperative Radiation Therapy

Immunostaining with Ki-67 monoclonal antibody was performed on frozen sections of biopsy specimens obtained before and during preoperative radiation therapy from 21 patients with head and neck squamous cell carcinoma. The Ki-67 labeling rates before radiation therapy and at radiation doses of 10 and 20 Gy ranged from 21 to 71% (mean: 35.0%), from 7 to 49% (mean: 25.8%) and from 1 to 44% (mean: 14.8%), respectively. One of the 2 patients whose tumors showing Ki-67 labeling rates of greater than 48% (mean +1 SD) before radiation therapy suffered local relapse shortly after the treatment. Moreover, tumors with rapidly decreased Ki-67 labeling rates (lower than 3%) at radiation doses of 20 Gy were related to poor clinical outcome: 4 out of 6 patients whose tumors showed Ki-67 labeling rates below 3% (mean -1 SD) at 20 Gy of irradiation had local relapses or showed distant metastases. These findings indicate that immunostaining with Ki-67 monoclonal antibody of biopsy specimens of head and neck squamous cell carcinoma, before and during radiation therapy, is very useful in assessing the clinical outcome of the patients.

Stereotactic radiosurgery (SRS) for multiple metastatic brain tumors : effects of the number of target tumors on exposure dose in normal brain tissues

AbstractBackground. This study was carried out to clarify the practical limit of the number of stereotactic radiosurgery (SRS)-targeted tumors based on the irradiation dose of normal brain tissues. Methods. Twenty-five patients with multiple brain metastases who received SRS from October 1998 to May 2002 were enrolled in the study. In each patient, the treatment options were thoroughly studied before deciding upon a course of treatment. The number of irradiated targets was increased one by one until all of the targets were included in a treatment plan. Given a surface dose of 25 Gy, we calculated the dose volume histogram (DVH) for the entire brain in each treatment plan and compared it with those of other treatment plans. Ultimately, only 5 of the 25 patients received irradiation for all of their tumors; the others received selective irradiation targeting only those tumors that were causing symptoms. Results. When the number of targets increased, the DVH curve shifted to the right. The volume of the brain irradiated at a dose of 5 Gy or higher was 25.7% or less for 4 or fewer targets, 45.7% for 5–6 targets, 81.0% for 7–8 targets and 100% for 9–11 targets. When the number of the targets exceeded 8, more than 50% of the entire brain was irradiated at levels of at least 8.7 Gy. The dose distribution became very complex as the number of targets increased. Although the survival time of the group in which tumors were selectively targeted was longer than that in the group in which all tumors were irradiated, the difference between the two groups was not statistically significant (P = 0.2537). Conclusion. In SRS for multiple brain metastases, risks of both acute and late sequelae may increase because the exposure dose to normal brain tissues increases with increased numbers of target tumors. Dose distribution becomes more complex according to the increase in the number of targets. Based on our DVH curves, we conclude that the exposure dose to normal brain tissues is acceptable when the number of targets is less than 7. Importantly, our study also reveals that it may not be necessary or desirable to irradiate all metastatic tumors.

Immunohistochemical Study of Mononuclear Cell Infiltrates in Squamous Cell Carcinoma of Oral Cavity and Paranasal Sinus

Serial frozen sections were prepared from 22 squamous cell carcinomas of oral cavity and paranasal sinus. Mononuclear cell infiltrates were stained by the biotin-avidin-horseradish peroxidase method using a panel of 10 mouse monoclonal antibodies to human leukocyte antigens. The degree of infiltration was graded from + + + (marked) to - (absent). The infiltration of anti-Leu-4-reactive cells (Leu-4+ cells) was grade + + or + + + in 14 of 22 cases. In 13 of 22 cases, infiltration of Leu-3a + 3b+ cells (helper/inducer T lymphocytes) was grade + + (moderate). In 5 of 20 cases, infiltration of Leu-2a+ cells (cytotoxic/suppressor T lymphocytes) was grade + +. As for B lymphocytes, infiltration of Leu-12+ cells was grade + + in only 2 of 19 cases. In conclusion, T lymphocyte infiltrates were commonly seen in squamous cell carcinoma in oral cavity and paranasal sinus and the number of patients with grade + + infiltration of helper/inducer T lymphocytes significantly predominated over that of patients with infiltration of cytotoxic/suppressor T lymphocytes grade + +.

TX-1877: design, synthesis, and biological activities as a BRM-functional hypoxic cell radiosensitizer

PURPOSE 2-Nitroimidazole acetamide TX-1877 and its derivatives (TX-1877 analogs) were designed, synthesized, and evaluated by their in vitro and in vivo radiosensitization, tumor growth control, suppression of lung metastasis, and immunopotentiation, as biological response modifier (BRM)-functional hypoxic cell radiosensitizers. MATERIALS AND METHODS TX-1877 analogs were designed and synthesized in our laboratory. In vitro radiosensitizing ability was estimated using EMT6/KU cells under hypoxic conditions. In vivo radiosensitization, antimetastasis, and immunopotentiation were evaluated using female C3H/He mice bearing the SCCVII tumor. Days (15 or 10) after the inoculation of 10(5) SCCVII tumor cells into the hinder thigh, a drug (0.4 mg/g) was administered i.p. and local irradiation of 30 Gy was given at 30 min after its administration. Tumor growth was observed for 20 days and mice were euthanized to count the number of metastatic nodules on the surface of the lungs. Tumor tissues were extirpated and stained by the ABC method at 1, 2, and 3 weeks after treatment for immunological evaluation. RESULTS Novel types of bifunctional radiosensitizers, TX-1877 and its analogs possessing BRM-functions (i.e., antimetastatic and immunopotentiation effects) were developed. In vitro radiosensitizing abilities of TX-1877 and its analogs, with their partition coefficient values of more than 0.050, were comparable to misonidazole (MISO) at their doses of 1 mM. Tumor regrowth was suppressed evidently 20 days after the treatment in the irradiated group with TX-1877 (TX-1877 plus R) and with KIN-806 (KIN-806 plus R). The former group reduced markedly the mean number of metastatic lung nodules regardless of radiation therapy. TX-1877 and KIN-806 plus R induced helper T lymphocytes. The TX-1877, TX-1877 plus R, KIN-806, and KIN-806 plus R enhanced macrophage infiltration for 3 weeks after treatment. CONCLUSION TX-1877 is an excellent BRM-functional hypoxic cell radiosensitizer, expected to be useful for clinical use.

Changes in Peripheral Lymphocyte Subsets during Radiotherapy for Lung Cancer Patients

In order to better understand the immunologic effects of irradiation, blood levels of lymphocyte subsets were sequentially monitored in 37 patients before and during irradiation treatment for lung cancer. During irradiation, the peripheral blood levels of each T cell subgroup, OKT3-reactive (OKT3+), OKT4+, OKT8+ and OKT11+ lymphocytes showed similar radiosensitivity. No selective depletion of either OKT4+ or OKT8+ lymphocytes was seen. The levels of OKT6+ and OKT9+ lymphocytes were different depending on the case. At the end of irradiation, the percent of lymphocytes bearing the OKT10 antigen increased significantly. As to OKM1+ and OKIa1+ lymphocytes, the levels were almost consistent but showed a rather big standard deviation.