Koji Enomoto

Augmentation of circulation of pedicled transverse rectus abdominis musculocutaneous flaps by microvascular surgery

The biggest problem of the TRAM flap for breast reconstruction is distal necrosis or fat lysis due to poor circulation. In order to utilise the entire TRAM flap tissue in extensive tissue defects, the contralateral rectus muscle is used as a pedicled carrier and the ipsilateral superficial or inferior epigastric vessels are anastomosed with appropriate recipient vessels in the axilla. This procedure has been performed in three cases with no necrosis, fat lysis or hardening of the flap tissue, proving adequate circulation in the flap.

Primary breast reconstruction after a standard radical mastectomy by a free flap transfer. Case report.

We present a successful clinical case (perhaps the first) of primary reconstruction of the breast after radical mastectomy by use of a free skin-fat-muscle flap.

Epidermal growth factor receptor-dependent cytotoxic effect by an EGF—ribonuclease conjugate on human cancer cell lines -A trial for less immunogenic chimeric toxin-

Abstract Mammalian pancreatic ribonuclease (RNase) was conjugated chemically via a disulfide bond to human or murine epidermal growth factor (EGF). The conjugation between EGF and RNase was ascertained by SDS-PAGE using reduced and nonreduced conjugates. The EGF–RNase conjugate retained potent RNase activity and competed with 125I-EGF for binding to EGFR to the same extent as unconjugated EGF. Both the human and murine EGF–RNase conjugates showed dose-dependent cytotoxicity against EGFR- overexpressing A431 human squamous carcinoma cells with IC50 values of 3×10-7 M and 6×10-7 M, respectively, whereas free RNase had an IC50 of 10-4 M. Against the EGFR-deficient small-cell lung cancer cell line H69, the EGF–RNase conjugate had no cytotoxic effect. The Human EGF–RNase conjugate showed dose-dependent cytotoxicity against other squamous carcinoma cell lines (TE-5, TE-1) and breast cancer cell lines (BT-20, SK-BR-3, MCF-7) and the cytotoxicity of the conjugate correlated positively with the level of expression of EGFR by each cell line. An unconjugated mixture of EGF and RNase had no greater effect than RNase alone on any cell line. Excess free EGF blocked EGF–RNase conjugate cytotoxicity against A431 cells. These results suggest that the EGF–RNase conjugate may be a more effective anticancer agent with less immunogenicity than coventional chimeric toxins.

Human breast carcinoma (MCF-7) serially transplanted into nude mice

The tumor cells (0.5 ml, 1×107) of MCF-7 line were inoculated into the subcutaneous tissue or intraperitoneum of female BALB/c nude mice. Primarily tansplanted mice were treated with 17β-estradiol dipropionate (E2) in a dose of 5 mg/kg and 17α-hydroxy progesterone caproate (Pg) in a dose of 250 mg/kg once a week. After the transferable strain was established, tumors were transplanted into female and male mice treated with E2, Pg, and E2+Pg. The tumors treated with E2 or E2+Pg grew exponentially while tumors in the other group regressed. Pg was assumed to play some role in the growth of MCF-7, in the presence of estrogen. Although cytosol estrogen receptors (ERc), nuclear estrogen receptors (ERn), and progesterone receptors (PgR) were detected by dextran coatedcharcoal method and exchange assay in the growing tumors, ERn and PgR of regressing tumors was usually negative. This MCF-7 strain in nude mice may be a promising animal model for studying chemo-hormone therapy for human breast carcinomas.

A phase III trial of oral high‐dose medroxyprogesterone acetate (MPA) versus mepitiostane in advanced postmenopausal breast cancer

A randomized controlled trial was performed to compare the therapeutic results of oral high‐dose medroxyprogesterone acetate (HD‐MPA) versus mepitiostane (MS) in the treatment of postmenopausal breast cancer. MPA was given at three doses of 400 mg orally daily to 47 patients and produced objective responses in 19 cases (40.4%). An objective response was seen in 14 of the 40 control patients given MS at two doses of 10 mg orally daily (35.0%). Among patients with bone metastases, 6 of 19 (31.6%) for HD‐MPA and 2 of 13 (15.4%) for MS showed objective responses. The other merits of HD‐MPA suggested in the study were improvement in performance status, increase in appetite, and myeloprotective effect.

Changes in the hormone receptors of human breast carcinoma xenografts in nude mice by treatment with cytotoxic agents

We examined the effect of chemotherapeutic agents on the estrogen receptors (ER) of breast carcinomasin vivo using human breast carcinoma strains (Br-10, T-61) serially transplanted into nude mice. When the tumor size reached approximately 1×1×1 cm, mitomycin C (MMC) at doses of 1, 2 and 4.5 mg/kg and cyclophosphamide (CPA) at a dose of 120 mg/kg, were administered once intraperitoneally, and the ERs of the tumors were measured sequentially by the dextran-coated charcoal method. Four days after the MMC administration at above doses, the binding sites of ER in Br-10 were not reduced and binding affinity was not affected. When the changes in ER content with time after the treatment with 4.5 mg/kg MMC and 120 mg/kg CPA were investigated, the ER content was found to be stable until 4 days after the treatment with both drugs, although the growth of T-61 had been significantly inhibited by the drugs. From these findings, it seems reasonable to initiate chemotherapy before endocrine therapy, since the chemotherapeutic agents did not reduce the ER content of the breast cancer strains.

Mode of Action of Estra-1,3,5(10)-triene-3,17β-diol 3-Benzoate 17-((4-(4-Bis(2-chloroethyl)amino)phenyl)-1-oxobutoxy)acetate) on Human Breast Carcinoma Xenografts in Nude Mice

To elucidate the mode of action of busramustine (KM2210), 17β‐ and α‐busramustine, estradiol and chlorambucil were used for experimental chemo‐ and endocrino‐therapy against hormone‐dependent (T‐61) and independent (MX‐1) human breast carcinomas serially transplanted into BALB/cA female nude mice. Busramustine was administered po daily for 3 weeks at doses of 12.5–300 mg/kg for the β‐isomer and 25–300 mg/kg for the α‐isomer. Five to 50 mg of estradiol per kg was administered im once, and 3 to 6 mg of chlorambucil per kg was administered po daily for 3 weeks. All of the compounds were effective against estrogen receptor‐positive T‐61 with a clear dose‐response relationship, while estrogen receptor‐negative MX‐1 was sensitive to all of the agents except estradiol. Since the α‐isomer of busramustine was effective against both tumor lines, the mode of action of 17β‐busramustine may not be related to estrogenic action by estradiol released from the maternal compound. However, 17bT‐busramustine generated the estrogen receptor system of T‐61 tumor and resulted in the endometrial hyperplasia of tumor‐bearing nude mice, suggesting that this compound also has estrogenic action on transplanted human breast carcinoma and tumor‐bearing host mice, besides non‐estrogenic antitumor activity on human breast carcinoma xenografts.

Phase II study of KRN8602, 3′-deamino-3′-morpholino- 13-deoxo-10-hydroxycarminomycin hydrochloride, MX2 · HCl in patients with metastatic breast cancer

Purpose: KRN8602 (3′-deamino-3′-morpholino-13-deoxo-10-hydroxycarminomycin hydrochloride, MX2 · HCl) is a newly developed anthracycline that has been found to be effective against multidrug-resistant tumor cells in vitro and in vivo. In order to clinically confirm these promising preclinical observations, we performed a phase II trial of KRN8602 in patients with anthracycline-resistant metastatic breast cancer. Methods: Of 41 patients registered with metastatic breast cancer, 37 were eligible and were given at least two cycles of KRN8602 15 mg/m2 per day at 3–4 week intervals by intravenous bolus injection on days 1, 2, and 3. Results: Of the 37 patients, 6 (16.2%, with a 95% confidence interval of 4.3–28.1%) had a partial response (PR). No complete responses (CRs) were observed. The difference between response rates according to prior history of anthracycline administration was not significant. Myelosuppression was moderately severe, with grade 3 or 4 leukopenia occurring in 65%. Severe nausea/vomiting was observed in 44% of the patients. Conclusions: The results indicate that KRN8602 has modest activity in refractory metastatic breast cancer and is associated with relatively severe toxicity. Furthermore, the preclinical finding that KRN8602 overcomes anthracycline resistance was not reliably reproduced in this clinical phase II trial.