Search

A 58-year-old woman presented with pelvic, para-aortic masses and two isolated nodules in the right lung 6 years after hysterectomy and bilateral salpingo-oophorectomy for uterine leiomyoma. Laparotomy was carried out and all the intra-abdominal tumors were excised; pathology showed metastatic low-grade leiomyosarcomas. Immunohistochemical staining revealed a high expression level of estrogen and progesterone receptors in these tumors. The pulmonary nodules were left and the patient was given oral medroxyprogesterone acetate 200 mg daily after the operation. One of the pulmonary masses regressed progressively and had disappeared 7 months later on chest X-ray examination. However, the other was persistent. She then received wedge resection to excise the pulmonary nodule, which showed the same histologic pattern as the abdomen masses. However, the immunohistochemical staining on this nodule showed positive estrogen receptor expression but was negative for progesterone receptor expression. After the operation, she maintained progestin treatment and was tumor free for the following 12 months.

Streptomycin is a common antibiotic used in culture media. It is also a known blocker of stretch-activated and mechanosensitive ion channels in neurons and cardiac myocytes. But very little information is available on its effect in the regulation of epithelial ion channels. Osmotic swelling is a kind of mechanical stretch. The opening of stretch-activated Ca(2+) channels contributes to hypotonicity-induced Ca(2+) influx which is necessary for the activation of volume-regulated Cl(-) channels in human cervical cancer cells. This study aimed to investigate the role of streptomycin in cell volume regulation. Treatment of cervical cancer SiHa cells with streptomycin and its analogues (gentamicin and netilmicin) did not affect the basal cytosolic Ca(2+) ([Ca(2+)](i)) level. But it attenuated the hypotonicity-stimulated increase of [Ca(2+)](i) in a dose-dependent manner with half-maximal inhibitory concentrations (IC(50)) of 25, 90 and 200 microM for streptomycin, gentamicin and netilmicin, respectively, when measured at room temperature. In contrast, under free extracellular Ca(2+) condition, hypotonic stress only induced a small, progressive increase of [Ca(2+)](i), while 500 microM streptomycin did not affect this Ca(2+) signaling. Streptomycin and its analogues (gentamicin and netilmicin) also inhibited the activation of volume-regulated Cl(-) channels in a dose-dependent manner with IC(50) of 30, 95 and 250 microM at room temperature, respectively. Chronic culture with 50 microM streptomycin downregulates the activity of volume-regulated Cl(-) channels and retards the process of regulatory volume decrease in SiHa cells and MDCK cells. We suggest that using cells chronically cultured with streptomycin to study epithelial ion channels risks studying cellular and molecular pathology rather than physiology.

This study aimed to examine the activation of poly(ADP-ribose) polymerase (PARP) and the accumulation of its end product, poly(ADP-ribose) (PAR), in uterine leiomyoma specimens obtained from 25 patients receiving Leuplin depot [leuprorelin acetate, depot (LA)] treatment and 46 control patients and explore their correlation with tumor shrinkage and degeneration caused by the therapy. Immunoblotting analysis showed that specimens from LA-treated patients had higher PARP expression. The numbers of both PARP- and PAR-immunolabeled cells were higher in leiomyoma with LA treatment. This was correlated with the clinical response of LA therapy that LA induced more leiomyoma degeneration. The analysis of power Doppler sonography indicated a progressive decrease in blood supply to tumor following LA treatment. In vitro experiments using primarily cultured leiomyoma cells exhibited that the deprivation of serum or ovarian hormones or LA directly failed to induce PARP and PAR production. Our results suggested that reduced blood flow and subsequent ischemic damages in leiomyoma could be responsible for PARP overexpression and PAR accumulation, clinical response, and tumor degeneration caused by LA treatment.

We report the case of a 31-year-old woman with an androgen-producing sclerosing stromal tumor found during the eighth week of gestation in association with ascites and elevated serum androgen and cancer antigen (CA)-125 levels. The combined features of ascites, elevated serum androgen and elevated CA-125 in association with this rare type of ovarian tumor is unusual. Surgical removal of the tumor resulted in relief of symptoms, resolution of ascites, and decreases in serum androgen and CA-125 levels. The pregnancy was uneventful.

Hypotonicity-induced Ca2+ entry is a critical signal for the normal regulatory volume decrease in human cervical cancer cells. The aim of this study was to explore the role of myosin light chain kinase (MLCK) in the regulation of hypotonicity-induced Ca2+ signalling and Cl- channel activity. Blockade of MLCK activity by MLCK(11-19) amide, a substrate-specific peptide inhibitor, markedly attenuated hypotonicity-induced Ca2+ entry. A similar result was obtained with ML-7, a synthetic naphthalenesulphonyl derivative that inhibits the binding of ATP to MLCK. More than 85% of the activity of the volume-regulated Cl- channel was suppressed when intracellular Ca2+ was buffered to near zero in the absence of extracellular Ca2+, suggesting that hypotonicity-induced Ca2+ signalling is important for the activation of the volume-regulated Cl- channel. Intracellular dialysis with MLCK(11-19) amide or ML-7 concentration-dependently reduced the amplitude and rate of activation of the volume-regulated Cl- channel. Swelling-activated taurine transport was also inhibited concentration dependently by ML-7 and MLCK(11-19) amide with IC(50) values of 6.4 and 2.0 microM, respectively. Hypotonicity induced MLC phosphorylation which was mediated totally by MLCK and depended on Ca2+ entry. However, phosphorylated MLC per se was not involved critically in the regulation of Ca2+ entry and activation of volume-sensitive organic osmolyte/anion channels (VSOAC). We propose that MLCK has a novel function in regulating the activation of VSOAC by mediating Ca2+ entry in response to hypotonicity. This function of MLCK on Ca2+ signalling does not correlate with MLC phosphorylation.

Intracellular pH (pH(i)) homeostasis was investigated in human cervical cancer SiHa cells undergoing regulatory volume decrease (RVD) to determine which transport systems were involved. Using isoform-specific primers, mRNA transcripts of Na(+)/H(+) exchanger isoform 1 (NHE1) and isoform 3 were identified by reverse transcriptase polymerase chain reaction (RT-PCR) and the results confirmed by Western immunoblotting. From anion exchanger isoforms 1-3 (AE1-3), only the mRNA transcript of AE2 was identified by RT-PCR and the identity was confirmed by digestion with a specific restriction endonuclease. SiHa cells loaded with the fluorescent dye 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein and resuspended in isotonic media showed a stable pH(i). In contrast, a gradual internal acidification took place following resuspension in hypotonic media. The NHE inhibitors, HOE694 (10 microM) and amiloride (1 mM), showed a similar potency in enhancing the rate and extent of the hypotonicity-induced internal acidification. The absence of extracellular Na(+) also substantially enhanced the acidification during RVD. These results suggest that internal acidification during RVD is mainly compensated by the operation of NHE1. Extracellular Cl(-) was critically necessary for the pH(i) acidification during RVD. The hypotonicity-induced acidification was significantly attenuated by 100 microM 4,4'-diisothiocyanostilbene-2,2'-disulfonic acid, a concentration inhibiting more than 90% AE activity. This indicates that AE2 mediates a net Cl(-) influx with compensating HCO(3)(-) efflux during RVD. We conclude that AE2 operates in parallel with NHE1 to regulate pH(i) during RVD of human cervical cancer cells.