Clinicopathological Significance of Loss of ARID1A Immunoreactivity in Ovarian Clear Cell Carcinoma

Recent genome-wide analysis has demonstrated that somatic mutations in ARID1A (BAF250) are the most common molecular genetic changes in ovarian clear cell carcinoma (OCCC). ARID1A mutations, which occur in approximately half of OCCC cases, lead to deletion of the encoded protein and inactivation of the putative tumor suppressor. In this study, we determined the significance of loss of ARID1A immunoreactivity with respect to several clinicopathological features in a total of 149 OCCCs. First, we demonstrated that ARID1A immunohistochemistry showed concordance with the mutational status in 91% of cases with 100% sensitivity and 66% specificity. Specifically, among 12 OCCC cases for which ARIDA mutational status was known, ARIDIA immunoreactivity was undetectable in all 9 cases harboring ARID1A mutations and was undetectable in one of 3 cases with wild-type ARID1A. With respect to the entire cohort, ARID1A immunoreactivity was undetectable in 88 (59%) of 149 OCCCs. There was no significant difference between ARID1A negative and positive cases in terms of histopathologic features, age, clinical stage, or overall survival. In conclusion, this study provides further evidence that mutations in ARID1A resulted in loss of ARID1A protein expression in OCCC, although no significant differences between ARID1A positive and negative cases were observed with respect to any clinicopathological features examined

Resveratrol promotes expression of SIRT1 and StAR in rat ovarian granulosa cells: an implicative role of SIRT1 in the ovary

<p>Abstract</p> <p>Background</p> <p>Resveratrol is a natural polyphenolic compound known for its beneficial effects on energy homeostasis, and it also has multiple properties, including anti-oxidant, anti-inflammatory, and anti-tumor activities. Recently, silent information regulator genes (Sirtuins) have been identified as targets of resveratrol. Sirtuin 1 (SIRT1), originally found as an NAD⁺-dependent histone deacetylase, is a principal modulator of pathways downstream of calorie restriction, and the activation of SIRT1 ameliorates glucose homeostasis and insulin sensitivity. To date, the presence and physiological role of SIRT1 in the ovary are not known. Here we found that SIRT1 was localized in granulosa cells of the human ovary.</p> <p>Methods</p> <p>The physiological roles of resveratrol and SIRT1 in the ovary were analyzed. Immunohistochemistry was performed to localize the SIRT1 expression. SIRT1 protein expression of cultured cells and luteinized human granulosa cells was investigated by Western blot. Rat granulosa cells were obtained from diethylstilbestrol treated rats. The cells were treated with increasing doses of resveratrol, and subsequently harvested to determine mRNA levels and protein levels. Cell viability was tested by MTS assay. Cellular apoptosis was analyzed by caspase 3/7 activity test and Hoechst 33342 staining.</p> <p>Results</p> <p>SIRT1 protein was expressed in the human ovarian tissues and human luteinized granulosa cells. We demonstrated that resveratrol exhibited a potent concentration-dependent inhibition of rat granulosa cells viability. However, resveratrol-induced inhibition of rat granulosa cells viability is independent of apoptosis signal. Resveratrol increased mRNA levels of SIRT1, LH receptor, StAR, and P450 aromatase, while mRNA levels of FSH receptor remained unchanged. Western blot analysis was consistent with the results of quantitative real-time RT-PCR assay. In addition, progesterone secretion was induced by the treatment of resveratrol.</p> <p>Conclusions</p> <p>These results suggest a novel mechanism that resveratrol could enhance progesterone secretion and expression of luteinization-related genes in the ovary, and thus provide important implications to understand the mechanism of luteal phase deficiency.</p

Genotype-Dependent Efficacy of a Dual PI3K/mTOR Inhibitor, NVP-BEZ235, and an mTOR Inhibitor, RAD001, in Endometrial Carcinomas

The PI3K (phosphatidylinositol-3-kinase)/mTOR (mammalian target of rapamycin) pathway is frequently activated in endometrial cancer through various PI3K/AKT-activating genetic alterations. We examined the antitumor effect of NVP-BEZ235—a dual PI3K/mTOR inhibitor—and RAD001—an mTOR inhibitor—in 13 endometrial cancer cell lines, all of which possess one or more alterations in PTEN, PIK3CA, and K-Ras. We also combined these compounds with a MAPK pathway inhibitor (PD98059 or UO126) in cell lines with K-Ras alterations (mutations or amplification). PTEN mutant cell lines without K-Ras alterations (n = 9) were more sensitive to both RAD001 and NVP-BEZ235 than were cell lines with K-Ras alterations (n = 4). Dose-dependent growth suppression was more drastically induced by NVP-BEZ235 than by RAD001 in the sensitive cell lines. G1 arrest was induced by NVP-BEZ235 in a dose-dependent manner. We observed in vivo antitumor activity of both RAD001 and NVP-BEZ235 in nude mice. The presence of a MEK inhibitor, PD98059 or UO126, sensitized the K-Ras mutant cells to NVP-BEZ235. Robust growth suppression by NVP-BEZ235 suggests that a dual PI3K/mTOR inhibitor is a promising therapeutic for endometrial carcinomas. Our data suggest that mutational statuses of PTEN and K-Ras might be useful predictors of sensitivity to NVP-BEZ235 in certain endometrial carcinomas

Loss of the SxxSS Motif in a Human T-Cell Factor-4 Isoform Confers Hypoxia Resistance to Liver Cancer: An Oncogenic Switch in Wnt Signaling

PURPOSE: Aberrantly activated Wnt/β-catenin signaling is important in hepatocellular carcinoma (HCC) development. Downstream gene expressions involving the Wnt/β-catenin cascade occur through T-cell factor (TCF) proteins. Here, we show the oncogenic potential of human TCF-4 isoforms based on the expression of a single conserved SxxSS motif. METHODS: We investigated the TCF-4J and K isoform pair characterized by the presence (K) or absence (J) of the SxxSS motif. The mRNA expression profiles were examined in 47 pairs of human HCCs and adjacent non-cancerous liver tissues by RT-PCR. Proliferation, sphere assays and immunoblot analysis were performed under normoxia and hypoxia conditions. The ability of HCC cells overexpressing TCF-4J (J cells) and K (K cells) to grow as solid tumors in nude mice was explored. RESULTS: TCF-4J expression was significantly upregulated in HCC tumors compared to corresponding peritumor and normal liver and was preferentially expressed in poorly differentiated HCCs. In contrast, TCF-4K was downregulated in those same HCC tumors. TCF-4J-overexpressing HCC cells (J cells) revealed a survival advantage under hypoxic conditions, high proliferation rate and formation of aggregates/spheres compared to overexpression of TCF-4K (K cells). The hypoxic J cells had high expression levels of HIF-2α and EGFR as possible mechanisms to promote tumorigenesis. Increased stability of HIF-2α under hypoxia in J cells was associated with a decreased level of von Hippel-Lindau (VHL) protein, a known E3 ligase for HIF-αs. In a xenograft model, the J cells rapidly developed tumors compared to K cells. Tumor tissues derived from J cells exhibited high expression levels of HIF-2α and EGFR compared to the slow developing and small K cell derived tumors. CONCLUSIONS: Our results suggest that the specific TCF-4J isoform, which lacks a regulatory SxxSS motif, has robust tumor-initiating potential under hypoxic conditions

FXYD3 functionally demarcates an ancestral breast cancer stem cell subpopulation with features of drug-tolerant persisters

乳がんの再発を起こす原因細胞を解明. 京都大学プレスリリース. 2023-11-16.The heterogeneity of cancer stem cells (CSCs) within tumors presents a challenge in therapeutic targeting. To decipher the cellular plasticity that fuels phenotypic heterogeneity, we undertook single-cell transcriptomics analysis in triple-negative breast cancer (TNBC) to identify subpopulations in CSCs. We found a subpopulation of CSCs with ancestral features that is marked by FXYD domain–containing ion transport regulator 3 (FXYD3), a component of the Na⁺/K⁺ pump. Accordingly, FXYD3⁺ CSCs evolve and proliferate, while displaying traits of alveolar progenitors that are normally induced during pregnancy. Clinically, FXYD3⁺ CSCs were persistent during neoadjuvant chemotherapy, hence linking them to drug-tolerant persisters (DTPs) and identifying them as crucial therapeutic targets. Importantly, FXYD3⁺ CSCs were sensitive to senolytic Na⁺/K⁺ pump inhibitors, such as cardiac glycosides. Together, our data indicate that FXYD3⁺ CSCs with ancestral features are drivers of plasticity and chemoresistance in TNBC. Targeting the Na⁺/K⁺ pump could be an effective strategy to eliminate CSCs with ancestral and DTP features that could improve TNBC prognosis

Inhibitory Effects of the New Bombesin Receptor Antagonist RC-3095 on the Luteinizing Hormone Release in Rats

The effects of bombesin receptor antagonist RC-3095 and gastrin-releasing peptide [GRP (14–27)] on basal luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone levels, as well as on the release of LH and FSH in response to LH-releasing hormone, were studied in normal and castrated male rats. We also examined the release of LH and FSH after intracerebroventricular injection of RC-3095 under different types of anesthesia (urethane, sodium pentobarbital, Metofane). Following injection of 10 µg RC-3095 into the lateral brain ventricle, serum LH levels were rapidly and significantly (p < 0.001) lowered. This effect lasted for at least 60 min and was not affected by the type of anesthetic used. Serum FSH levels were not affected by intracerebroventricular administration of RC-3095 or GRP (14–27), indicating different central control mechanisms between LH and FSH release. The suppressive effect of RC-3095 on LH release could be completely prevented by prior intracerebroventricular administration of GRP (14–27) at a dose of 1 µg, but intravenous administration of either peptide RC-3095 or GRP (14–27) did not change the basal levels of LH, FSH, and testosterone. The pituitary LH response to LH-releasing hormone was also not modified by intravenous administration of RC-3095. These results indicate that bombesin-like peptides might be involved in control of LH release from the pituitary by an action on the CNS which is mediated by specific bombesin receptors

Inhibition of human epithelial ovarian cancer cell growth in vitro by agonistic and antagonistic analogues of luteinizing hormone-releasing hormone (cell proliferation/(3H)thymidine incorporation/luteinizing hormone-releasing hormone receptor/gynecologic cancer)

In this study, we investigated the effects of luteinizing hormone-releasing hormone (LH-RH) agonist (D-Trp6)LH-RH, LH-RH antagonist (Ac-D-Nal(2)1,D- Phe(pCI)2,D-Pal(3)3,D-Cit6,D-Ala'0)LH-RH (SB-75), and estra- diol on the growth of human epithelial ovarian cancer cell line OV-1063. Cells were cultured under estrogen-deprived condi- tions. Estradiol inhibited cell proliferation, as measured by cell number at 10-9-10-7 M and p3H)thymidine incorporation into DNA at 10-'3-10-9 M. Both LH-RH analogs inhibited cell growth dose dependently in the range 10-8_10-5 M, but SB-75 induced a greater growth inhibition than (D-Trp6)LH-RH. In OV-1063 cells, 1251-labeled (D-Trp6)LH-RH was bound to one class of specific, saturable binding sites with high affinity (Kd - 1.4 ? 0.3 nM) and low capacity (4000 binding sites per cell). I-51_labeled (D-Trp6)LH-RH could be displaced by unlabeled (D-Trp6)LH-RH and SB-75, suggesting that both analogs are bound to the same receptor on OV-1063 cells. Ligand binding was dependent on time and temperature. Receptor internal- ization assay showed that the ligand-receptor complex was internalized at 37?C, which indicates the presence of biologi- cally active LH-RH receptors on OV-1063 cells. These results suggest that estradiol and LH-RH analogs can suppress the growth of OV-1063 human epithelial ovarian cancer cells by a direct action and that the inhibitory effect of LH-RH analogs is mediated through the high-affinity LH-RH receptors

Stimulation by Bombesin and Inhibition by Bombesin/Gastrin-releasing Peptide Antagonist RC-3095 of Growth of Human Breast Cancer Cell Lines

Recently, it was reported that bombesin/gastrin-releasing peptide (GRP) have mitogenic effects on some human breast cancer cell lines. In this study, we investigated the effects of bombesin/GRP and its receptor antagonist (RC-3095) on the proliferation of three breast cancer cell lines, MDA-MB-231, MCF-7 MIII, and MCF-7. Stimulation by bombesin and inhibition by RC-3095 of cell growth were found in MDA-MB-231 and MCF-7 MIII cells cultured in phenol red-free medium with 5% heat-inactivated and dextran-coated charcoal-treated fetal bovine serum (DCC-FBS). A stimulatory effect by bombesin was not observed in the presence of untreated FBS. [3H]Thymidine incorporation into DNA in these cells was suppressed by RC-3095. MCF-7 cells failed to respond to bombesin and RC-3095 in the presence of either FBS or DCC-FBS. GRP-like immunoreactivity was found in the cell extracts and FBS, but it was undetectable in DCC-FBS. It appears that the stimulatory effect of bombesin on cell proliferation of MCF-7 MIII and MDA-MB-231 cell lines could be obtained because of reduction in the levels of some serum factors in DCC-FBS. These results suggest that bombesin/GRP can act as growth factors through bombesin/GRP receptors in some human breast cancers

Effect of Luteinizing Hormone-Releasing Hormone Analogs on the Rat Ovarian Follicle Development

Our objective was to study the direct action of luteinizing hormone-releasing hormone (LHRH) agonist buserelin and LHRH antagonist Cetrorelix (SB-75) on cell proliferation and differentiation in the rat ovarian follicle. Preovulato-ry follicles were isolated from PMSG-primed immature rats and incubated in the presence or absence of hCG (10 IU/ml), buserelin (10-9-10-6M) or Cetrorelix (10-9-10-6M) for 12 h in vitro. Buserelin induced meiotic maturation of the follicle-enclosed oocytes dose-dependently. The percentage of oocytes with germinal vesicle breakdown at 10-6M buserelin (73.3%) did not differ from that of hCG-treated control (73.3%). Buserelin also significantly stimulated prostaglandin E2 and progesterone production by follicles, but not estradiol production. Granulosa cells were obtained from the preovulatory follicles and cultured for 5 days. Epidermal growth factor (EGF) stimulated granulosa cell growth at concentrations of 1, 10 and 100 ng/ml. In contrast, both buserelin and Cetrorelix inhibited granulosa cell growth dose-dependently in the range of 10-10-10-5 M, with Cetrorelix inducing a greater growth inhibition than buserelin. Electrophoretic analysis of genomic DNA extracted from granulosa cells treated with 10-6M concentration of either LHRH analog revealed a definitive ladder pattern of oligonucleosomal length DNA fragments characteristic of apoptosis. Western blotting detected that EGF-induced tyrosine phosphorylation was not affected by either analog. These results demonstrate that LHRH agonist and antagonist inhibit directly proliferation of granulosa cells through apoptosis, without interference with EGF receptor phosphorylation, whereas LHRH agonist stimulates cell differentiation in the preovulatory follicle