Kaoru Saito

Differential growth inhibitory effect of melatonin on two endometrial cancer cell lines.

The effect of melatonin on endometrial cancer cell growth was investigated using two cell lines, SNG‐II and Ishikawa, which are different in their estrogen receptor status. A physiological concentration of melatonin (10−9 M) showed no growth inhibitory effect on SNG‐II cells, which are estrogen receptor‐negative at all cell densities and incubation times. In contrast, melatonin significantly inhibited Ishikawa cells, which are estrogen receptor‐positive at all cell densities tested after 96 hr incubation. The greatest inhibition of Ishikawa cell growth was observed at 10−9 M melatonin, compared with other supra (10−6, 10−8 M) or subphysiological concentrations (10−10, 10−12 M). This growth inhibitory effect of melatonin on Ishikawa cells was completely blocked by 10−10 to 10−8 M concentrations of 17‐β estradiol administration. Pretreatment with luzindole, which is a selective melatonin receptor antagonist, prior to the addition of melatonin also blocked the inhibitory effect of melatonin on Ishikawa cells. This is the first study to demonstrate an anti‐proliferative effect of physiological melatonin on endometrial cancer cells in vitro. The present study revealed that melatonin also inhibits the growth of estrogen receptor positive endometrial cancer cells and that this effect of the pineal indole may be mediated by both steroid and melatonin receptors.

Expression of Apg-1, a member of the Hsp110 family, in the human testis and sperm

Apg‐1 encodes a heat shock protein belonging to the Hsp110 family and is inducible by a 32°C to 39°C heat shock in somatic cells. In mouse testicular germ cells Apg‐1 mRNA is constitutively expressed depending on the developmental stage. As human Apg‐1 has recently been identified, the expression of Apg‐1 in the human testis and sperm was investigated.

Myxoid Variant of Epithelioid Leiomyosarcoma of the Uterus

A rare case of myxoid variant of epithelioid leiomyosarcoma of the uterus in a 76‐year‐old woman is reported. Palpation and computed tomography revealed an enlarged uterus. Total hysterectomy and bilateral salpingo‐oophorectomy were performed, and a hemispheric tumor, measuring 2.7 X 2.5 X 1.8 cm, was found protruding into the uterine cavity of the upper uterine segment. The tumor contained a prominent myxoid stroma and epithelioid tumor cells, which were round and polygonal in shape and showed positive immunoreactivity for desmin and vimentin. High mitotic activity was observed in the tumor cells. Electron microscopic examination revealed bundles of filaments in the cytoplasm and fine reticular material in the extracellular matrix. Histochemically, the myxoid stroma contained abundant acid mucopolysaccharide. The tumor cells were considered to originate from smooth muscle cells, while the myxoid stroma expressed varying differentiation of uterine mesenchymal cells. The patient is currently well with no evidence of recurrence or metastasis one year after the operation. Acta Pathol Jpn 41: 778‐783, 1991.

Establishment and characterization of a cell-line originated from human mucinous cystadenocarcinoma of the ovary.

We recently established a cell line (designated 371M) derived from an ovarian mucinous cystadenocarcinoma. The tumor cells were obtained from the ascitic fluid of a 54-year-old Japanese woman while she was undergoing surgery. Adjuvant chemotherapy (combined paclitaxel and carboplatin) was administered, but was ineffective, and she died about 4 months after surgery. The 371M cells continuously propagated in vitro over a period of about 50 months and, to date, have undergone over 100 passages. They proliferated in a monolayered sheet with doubling times of 84 h and 37 h in the 10th and 34th passages, respectively. When transplanted into nude mice, the tumor histopathologically resembled the structure of the original tumor. The 371M cells secreted high levels of CA125 and CA19-9 into the culture medium. There were several abnormal chromosomes in all karyotypes selected at random. Sensitivity of 371M cells to a variety of anti-cancer drugs was examined by in vitro MTT assay, and the results suggested that CPT-11 and CDDP were more effective against 371M cells than other anti-cancer agents.

Malignant Melanoma of the Kidney Presenting as a Primary Tumor

We report a case of malignant melanoma of the kidney presenting as a primary tumor. This tumor was found incidentally in a 74‐year‐old woman. The patient underwent a right radical nephrectomy, and has been living tumor free for 2 years and 3 months. This is the first reported case of primary renal malignant melanoma. We discuss the probability that this tumor is renal in origin and directly linked to the origin of malignant melanoma.