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Biomedical subjects

Y Hirokawa

Publications and source records attributed to Y Hirokawa.

104 records · Page 6Linked to original sources

Adeno-associated virus vector mediated transduction of primary normal human breast epithelial cells.

Cultured human breast epithelial cells from reduction mammoplasty specimens were transduced using an adeno-associated virus vector encoding the marker gene E. coli -galactosidase. Subconfluent, growing, breast epithelial cells were more easily transduced than confluent, quiescent, cells. Transduction of non-dividing confluent cells could be greatly increased by ultraviolet light-induced DNA damage or by prior exposure to the DNA synthesis inhibitor hydroxyurea. The effects of ultraviolet light and hydroxyurea on transduction were additive when these agents were applied together.

Breast↗

Radiotherapy combined with transcatheter arterial infusion of cisplatin versus oral fluoropyrimidine anticancer agent for locally advanced carcinoma of the uterine cervix: a prospective follow-up study.

We randomized patients with locally advanced cervical cancer to receive radiotherapy combined with transcatheter arterial infusion (TAI) of cisplatin or oral fluoropyrimidine anticancer agents, and compared the prognosis by a prospective follow-up study. Sixty patients were studied who completed their planned radiation therapy with chemotherapy at the Department of Obstetrics and Gynecology of Hiroshima University Hospital between January 1991 and December 1998. Patients were randomly assigned to receive (A) radiotherapy with TAI of 120 mg/body cisplatin twice a month at the interval of 4 weeks or (B) radiotherapy with 200 mg/day oral 5-FU or UFT every day. In both groups, radiotherapy is routinely 50 Gy of external beam irradiation to the whole pelvis and 18-20 Gy (point A dose) of intracavitary irradiation using a remote after loading system (RALS). Serious adverse reactions interfering with treatment did not appear in either group. The effective histologic response was 28/32 (87.5%) in group A and 25/28 (89.3%) in group B. The median follow-up period were 28.3 months and 25.4 months in group A and B, respectively. There was no significant difference in the overall survival and disease-free survival rates for all patients, clinical stage III and squamous cell carcinoma. We could not conclude that radiotherapy with TAI of cisplatin achieved superior therapeutic efficacy in locally advanced cervical cancer. To improve the therapeutic effects, it is important to establish a new cisplatin-containing chemoradiotherapy regimen.

Adenocarcinoma↗

Treatment of ras-induced cancers by the F-actin-bundling drug MKT-077.

A rhodacyanine dye called MKT-077 has shown a highly selective toxicity toward several distinct human malignant cell lines, including bladder carcinoma EJ, and has been subjected to clinical trials for cancer therapy. In the pancreatic carcinoma cell line CRL-1420, but not in normal African green monkey kidney cell line CV-1, it is selectively accumulated in mitochondria. However, both the specific oncogenes responsible for its selective toxicity toward cancer cells, and its target proteins in these cancer cells, still remain to be determined. This study was conducted using normal and ras-transformed NIH 3T3 fibroblasts to determine whether oncogenic ras mutants such as v-Ha-ras are responsible for the selective toxicity of MKT-077 and also to identify its targets, using its derivative called "compound 1" as a specific ligand. We have found that v-Ha-ras is responsible for the selective toxicity of MKT-077 in both in vitro and in vivo. Furthermore, we have identified and affinity purified at least two distinct proteins of 45 kD (p45) and 75 kD (p75), which bind MKT-077 in v-Ha-ras-transformed cells but not in parental normal cells. Microsequencing analysis has revealed that the p45 is a mixture of beta- and gamma-actin, whereas the p75 is HSC70, a constitutive member of the Hsp70 heat shock adenosine triphosphatase family, which inactivates the tumor suppressor p53. MKT-077 binds actin directly, bundles actin filaments by cross-linking, and blocks membrane ruffling. Like a few F-actin-bundling proteins such as HS1, alpha-actinin, and vinculin as well as F-actin cappers such as tensin and chaetoglobosin K (CK), the F-actin-bundling drug MKT-077 suppresses ras transformation by blocking membrane ruffling. These findings suggest that other selective F-actin-bundling/capping compounds are also potentially useful for the chemotherapy of ras-associated cancers.

3T3 Cells↗

An anti-Ras cancer potential of PP1, an inhibitor specific for Src family kinases: in vitro and in vivo studies.

BACKGROUND: We previously found that both PAK, a Rac/CDC42-activated Ser/Thr kinase, and its binding partner PIX are required for malignant transformation caused by oncogenic Ras mutants, such as v-Ha-Ras. Furthermore, oncogenic Ras requires an autocrine pathway to activate PAK. This pathway involves at least two distinct receptor kinases: EGF receptor (ErbB1) and ErbB2. Interestingly, both of these kinases are known to activate Src family kinases that phosphorylate CAT, another binding partner of PIX. PURPOSE: The major aim of this study was to determine whether Src family kinases are required for both Ras-induced PAK activation and malignant transformation. For this purpose, we used PP1, an inhibitor specific for Src family kinases, which does not inhibit either EGF receptor or ErbB2. METHODS AND RESULTS: We studied the effect of PP1 on the anchorage-dependent growth of normal and v-Ha-Ras transformed NIH 3T3 fibroblasts, PAK activation and anchorage-independent growth of Ras transformants, and development of Ras-induced sarcomas in nude mice. We found that PP1 (10 nM) strongly inhibits PAK activity in Ras transformants. PP1 at this concentration is known to inhibit c-Fyn kinase, but not c-Src kinase, and none of the three known Src family kinases (c-Src, c-Fyn, and c-Yes) expressed in fibroblasts is activated by v-Ha-Ras. Thus, it is most likely that the primary target of this drug is an as yet unidentified Ras-activated Tyr (Y) kinase or kinases, which we call "Ray." Although PP1 has no effect on their anchorage-dependent growth, it significantly inhibits their anchorage-independent growth in soft agar, as well as a rapid growth of Ras-induced sarcomas in mice. CONCLUSION: Like EGF receptor and ErbB2, a member of Src family kinases (most likely a new Src-related kinase called "Ray") is essential for the Ras-induced activation of PAK and the malignant transformation both in vitro and in vivo. These findings suggest that PP1 and other inhibitors specific for Src family kinases are potentially useful for the treatment of Ras-associated cancers.

3T3 Cells↗

Signal therapy for RAS-induced cancers in combination of AG 879 and PP1, specific inhibitors for ErbB2 and Src family kinases, that block PAK activation.

BACKGROUND: Both EGF family ligands and ErbB family receptor kinases act upstream of RAS to induce mitogenesis of normal cells, such as NIH 3T3 fibroblasts. However, oncogenically mutated RAS, such as v-Ha-RAS is constitutively activated and therefore no longer requires these ligands or receptors for its activation. Nevertheless, it up-regulates the expression of these EGF family ligands. To understand the biologic significance of RAS-induced up-regulation of these ligands in both RAS-induced PAK activation and malignant transformation, we have conducted the following studies, based on the previous observations that (1) the N-terminal SH3 domain of PIX selectively binds a Pro-rich domain of 18 amino acids of PAKs, CDC42/Rac-dependent Ser/Thr kinase family, and (2) this specific interaction is essential for both PAK activation and membrane ruffling RESULTS: Using four distinct, cell-permeable, and highly specific inhibitors, namely WR-PAK18, which blocks the PAK-PIX interaction; AG 1478, which inhibits ErbB1 kinase activity; and AG 825 or AG 879, which inhibits ErbB2 kinase activity, we demonstrate that (1) the PAK-PIX interaction is essential for v-Ha-RAS-induced malignant transformation; (2) v-Ha-RAS requires not only ErbB1 but also ErbB2, which are activated through two independent autocrine pathways to induce both the PIX/Rac/CDC42-dependent PAK activation and malignant transformation in vitro; and (3) a combination of AG 879 and the Src family kinase-specific inhibitor PP1 suppresses almost completely the growth of RAS-induced sarcomas in nude mice. CONCLUSION: These findings not only change our conventional view on the role of these RAS-inducible ligands and ErbB family receptors (serving as RAS activators) but also suggest a new avenue for the treatment of RAS-associated cancers by a combination of inhibitors specific for ERbB, Src, or PAK family kinases.

3T3 Cells↗

Consistency of variables in PCS and JASTRO great area database.

PURPOSE: To examine whether the Patterns of Care Study (PCS) reflects the data for the major areas in Japan, the consistency of variables in the PCS and in the major area database of the Japanese Society for Therapeutic Radiology and Oncology (JASTRO) were compared. METHODS AND PATIENTS: Patients with esophageal or uterine cervical cancer were sampled from the PCS and JASTRO databases. From the JASTRO database, 147 patients with esophageal cancer and 95 patients with uterine cervical cancer were selected according to the eligibility criteria for the PCS. From the PCS, 455 esophageal and 432 uterine cervical cancer patients were surveyed. Six items for esophageal cancer and five items for uterine cervical cancer were selected for a comparative analysis of PCS and JASTRO databases. RESULTS: Esophageal cancer: Age (p=.0777), combination of radiation and surgery (p=.2136), and energy of the external beam (p=.6400) were consistent for PCS and JASTRO. However, the dose of the external beam for the non-surgery group showed inconsistency (p=.0467). Uterine cervical cancer: Age (p=.6301) and clinical stage (p=.8555) were consistent for the two sets of data. However, the energy of the external beam (p<.0001), dose rate of brachytherapy (p<.0001), and brachytherapy utilization by clinical stage (p<.0001) showed inconsistencies. CONCLUSION: It appears possible that the JASTRO major area database could not account for all patients' backgrounds and factors and that both surveys might have an imbalance in the stratification of institutions including differences in equipment and staffing patterns.

Adult↗

Prognostic factors for patients with esophageal cancer treated with radiation therapy in PCS: a preliminary study.

PURPOSE: We investigated the prognostic factors, with special reference to age, for esophageal cancer patients, who did not receive surgery but were treated with radiation in the context of a Patterns of Care Study (PCS) in Japan. PATIENTS AND METHODS: The fifth PCS database format employed in the United States was used to collect information on 455 esophageal cancer patients by external audit. The data of patients who had not received surgery (n=252) were further selected and divided into two age groups, patients 75 years old or older (n=90) and patients younger than 75 years (n=162). Cox's proportional hazards model was used for the statistical analysis, with crude survival as the endpoint. Variables tested were age; Karnofsky performance status (KPS); history of pulmonary disease, cardiovascular disease, and diabetes; AJCC stage; external dose; treatment period; combination with chemotherapy; utilization of brachytherapy, and stratification of institutions. RESULTS: Statistically significant prognostic factors for all patients in the non-surgery group were KPS p=.0001), stage (p=.0001), and utilization of brachytherapy (p=.0102). For younger patients, KPS (p=.0001), stage (p=.0007), external dose (p=.0001), and utilization of brachytherapy (p=.0034) were significant, and for the elderly, stage (p=.0001) and external dose (p=.0006). CONCLUSION: Although this was a preliminary study, age was not a significant prognostic factor for esophageal cancer patients in the non-surgery group, and making the external dose more than 60 Gy appears to be effective for improving survival of elderly as well as younger patients.

Adenocarcinoma↗