Evidence is accumulating that solid tumors contain a rare phenotypically distinct population of cells, termed cancer stem cells (CSC), which give rise to and maintain the bulk of the tumor. These CSC are thought to be resistant to current chemotherapeutic strategies due to their intrinsic stemlike properties and thus may provide the principal driving force behind recurrent tumor growth. Given the high frequency of recurrent metastasis associated with human ovarian cancer, we sought to determine whether primary human ovarian tumors contain populations of cells with enhanced tumor-initiating capacity, a characteristic of CSC. Using an in vivo serial transplantation model, we show that primary uncultured human ovarian tumors can be reliably propagated in NOD/SCID mice, generating heterogeneous tumors that maintain the histological integrity of the parental tumor. The observed frequency of tumor engraftment suggests only certain subpopulations of ovarian tumor cells have the capacity to recapitulate tumor growth. Further profiling of human ovarian tumors for expression of candidate CSC surface markers indicated consistent expression of CD133. To determine whether CD133 expression could define a tumor-initiating cell population in primary human ovarian tumors, fluorescence-activated cell sorting (FACS) methods were employed. Injection of sorted CD133 1 and CD133 2 cell populations into NOD/SCID mice established that tumor-derived CD133 1 cells have an increased tumorigenic capacity and are capable of recapitulating the original heterogeneous tumor. Our data indicate that CD133 expression defines a NOD/SCID tumor initiating subpopulation of cells in human ovarian cancer that may be an important target for new chemotherapeutic strategies aimed at eliminating ovarian cancer.

Background: Triple-negative breast cancer (TNBC) accounts for 15-20% of breast cancers but is responsible for a disproportionate number of deaths. We investigated the relevance, in TNBC, of nano-sized exosomes expelled from cells. Specifically, we compared effects of exosomes derived from the claudin-low TNBC cell line Hs578T and its more invasive Hs578Ts(i) 8 variant, as well as exosomes from TNBC patient sera compared to normal sera. Methods: Exosomes were isolated from conditioned media (CM) of Hs578T and Hs578Ts(i) 8 cells and from sera by filtration and ultracentrifugation. Successful isolation was confirmed by transmission electron microscopy and immunoblotting. Subsequent analysis, of secondary/ recipient cells in response to exosomes, included proliferation; motility/migration; invasion; anoikis assays and endothelial tubule formation assays. Results: Hs578Ts(i) 8 -exosomes versus Hs578T-exosomes significantly increased the proliferation, migration and invasion capacity of all three recipient cell lines evaluated i.e. SKBR3, MDA-MB-231 and HCC1954. Exosomes from Hs578Ts(i) 8 cells also conferred increased invasiveness to parent Hs578T cells. Hs578Ts(i) 8 -exosomes increased sensitivity of SKBR3, MDA-MB-231 and HCC1954 to anoikis when compared to the effects of Hs578T-exosomes reflecting the fact that Hs578Ts(i) 8 cells are themselves innately more sensitive to anoikis. In relation to vasculogenesis and subsequent angiogenesis, Hs578Ts(i) 8 -exosomes versus Hs578T-exosomes stimulated significantly more endothelial tubules formation. Finally, our 0959-8049/$ -see front matter Ó

BACKGROUND Successful treatment of breast cancer is enhanced by early detection and, if possible, subsequent patient-tailored therapy. Toward this goal, it is essential to identify and understand the most relevant panels of biomarkers, some of which may also have relevance as therapeutic targets. METHODS We critically reviewed published literature on microRNAs (miRNAs) as relevant to breast cancer. SUMMARY Since the initial recognition of the association of miRNAs with breast cancer in 2005, studies involving cell lines, in vivo models, and clinical specimens have implicated several functions for miRNAs, including suppressing oncogenesis and tumors, promoting or inhibiting metastasis, and increasing sensitivity or resistance to chemotherapy and targeted agents in breast cancer. For example, miR-21 is overexpressed in both male and female breast tumors compared with normal breast tissue and has been associated with advanced stage, lymph node positivity, and reduced survival time. miR-21 knock-down in cell-line models has been associated with increased sensitivity to topotecan and taxol in vitro and the limitation of lung metastasis in vivo. Furthermore, the discovery of extracellular miRNAs (including miR-21), existing either freely or in exosomes in the systemic circulation, has led to the possibility that such molecules may serve as biomarkers for ongoing patient monitoring. Although additional investigations are necessary to fully exploit the use of miRNAs in breast cancer, there is increasing evidence that miRNAs have potential not only to facilitate the determination of diagnosis and prognosis and the prediction of response to treatment, but also to act as therapeutic targets and replacement therapies.

Emerging evidence indicates that the highly regenerative human endometrium harbors rare populations of epithelial progenitor cells. In tumors of other regenerative epithelial tissues, rare cancer stem cells (CSC) have been identified that may have originated from normal epithelial stem/progenitor cells. We hypothesized that CSC are responsible for epithelial neoplasia associated with endometrial carcinoma, the most common gynecologic malignancy in women. Stem cell characteristics of single cells isolated from endometrial carcinoma tissues from women ages 62 ± 11.8 years (n = 34) were assessed.

OBJECTIVE:To investigate the independent influence of alterations in fat mass, body fat distribution and hormone release on pubertal increases in fasting serum insulin concentrations and on insulin resistance assessed by the homeostasis model (HOMA). DESIGN AND SUBJECTS: Cross-sectional investigation of pre-(n ¼ 11, n ¼ 8), mid-(n ¼ 10, n ¼ 11), and late-pubertal (n ¼ 10, n ¼ 11) boys and girls with normal body weight and growth velocity. MEASUREMENTS: Body composition (by a four-compartment model), abdominal fat distribution and mid-thigh interfascicular plus intermuscle (extramyocellular) fat (by magnetic resonance imaging), total body subcutaneous fat (by skinfolds), mean nocturnal growth hormone (GH) release and 06:00 h samples of serum insulin, sex steroids, leptin and insulin-like growth factor-I (IGF-I). RESULTS: Pubertal insulin resistance was suggested by greater (P < 0.001) fasting serum insulin concentrations in the latepubertal than pre-and mid-pubertal groups while serum glucose concentrations were unchanged and greater (P < 0.001) HOMA values in late-pubertal than pre-and mid-pubertal youth. From univariate correlation fat mass was most related to HOMA (r ¼ 0.59, P < 0.001). Two hierarchical regression models were developed to predict HOMA. In one approach, subject differences in sex, pubertal maturation, height and weight were held constant by adding these variables as a block in the first step of the model (r 2 ¼ 0.36). Sequential addition of fat mass (FM) increased r 2 (r 2 (inc)remental ¼ 0.08, r 2 ¼ 0.44, P < 0.05) as did the subsequent addition of a block of fat distribution variables (extramyocellular fat, abdominal visceral fat, and sum of skinfolds; r 2 inc ¼ 0.11, r 2 ¼ 0.55, P < 0.05). Sequential addition of a block of hormone variables (serum IGF-I and log (10) leptin concentrations; r 2 inc ¼ 0.04, P > 0.05) did not reliably improve r 2 beyond the physical characteristic and adiposity variables. In a second model, differences in sex and pubertal maturation were again held constant (r 2 ¼ 0.25), but body size differences were accounted for using percentage fat data. Sequential addition of percentage body fat (r 2 (inc)remental ¼ 0.11, r 2 ¼ 0.36, P < 0.05), then a block of fat distribution variables (percentage extramyocellular fat, percentage abdominal visceral fat, and percentage abdominal subcutaneous fat; r 2 inc ¼ 0.08, r 2 ¼ 0.44, P ¼ 0.058), and then a block of serum IGF-I and log (10) leptin concentrations (r 2 inc ¼ 0.07, r 2 ¼ 0.51, P < 0.05) increased r 2 . Mean nocturnal GH release was not related to HOMA (r ¼ 7 0.04, P ¼ 0.75) and therefore was not included in the hierarchical regression models. CONCLUSION: Increases in insulin resistance at puberty were most related to FM. Accumulation of fat in the abdominal visceral, subcutaneous and muscular compartments may increase insulin resistance at puberty beyond that due to total body fat. Serum concentrations of leptin and IGF-I may further modulate HOMA beyond the effects of adiposity and fat distribution. However, the results...

Recent data suggest that rare stem cell populations with the capacity to self renew and drive tumor formation are a feature of solid tumors. Several investigators have identified putative stem cells from solid tumors and cancer cell lines following isolation of a side population (SP) defined by dye exclusion. We investigated this parameter in our efforts to identify an endometrial cancer (EnCa) stem cell population. Multiple EnCa cell lines were assessed and verapamil sensitive SP and non-SP cells were isolated from two human EnCa cell lines. The functional significance of the SP and non-SP derived from AN3CA was evaluated in vitro and in vivo. SP cells proliferated at a significantly slower rate than the non-SP fraction, and a larger proportion of the SP cells were in the G 1 phase of the cell cycle as compared to the non-SP fraction. The SP fraction was more resistant to the chemotherapeutic agent paclitaxel. The SP comprised ~0.02% of the initial AN3CA cell population and this proportion of SP cells was maintained within the larger heterogeneous population following repeated passages of purified SP cells. These findings suggest that SP cells derived from the AN3CA cell line have the stem cell properties of low proliferative activity, chemoresistance and self-renewal. We also tested relative tumor formation activity of the SP and non-SP fractions. Only the SP fraction was tumorigenic. Additionally, we identified SP fractions in primary EnCa. Together these results are consistent with the hypothesis that EnCa contain a subpopulation of tumor initiating cells with stem like properties.

Both endogenous and exogenous cannabinoids exert a potent and direct relaxant effect on human pregnant myometrium, which is mediated through the CB(1) receptor. This highlights a possible role for endogenous cannabinoids during human parturition and pregnancy. These results also support the view that the use of exogenous cannabinoids during pregnancy is not linked independently with preterm labor.

Endometrial cancer is the leading gynecologic cancer in women in the United States with 52,630 women predicted to be diagnosed with the disease in 2014. The objective of this study was to determine if progesterone (P4) receptor membrane component 1 (PGRMC1) influenced endometrial cancer cell viability in response to chemotherapy in vitro and in vivo. A Jentiviral-based shRNA knockdown approach was used to generate stable PGRMC1-intact and PGRMC1-deplete Ishikawa endometrial cancer cell lines that also lacked expression of the classical progesterone receptor (PGR). Progesterone treatment inhibited mitosis of PGRMC1-intact, but not PGRMC1-deplete cells, suggesting that PGRMC1 mediates the anti-mitotic actions of P4.To test the hypothesis that PGRMC1 attenuates chemotherapy-induced apoptosis, PGRMC1-intact and PGRMC1-deplete cells were treated in vitro with vehicle, P4 (1 μM), doxorubicin (Dox. 2 μg/ml). or P4 + Dox for 48 h. Doxorubicin treatment of PGRMC1-intact cells resulted in a significant increase in cell death; however, co-treatment with P4 significantly attenuated Dex-induced cell death. This response to P4 was lost in PGRMC1-deplete cells. To extend these observations in vivo, a xenograft model was employed where PGRMC1-intact and PGRMC1-deplete endometrial tumors were generated following subcutaneous and intraperitonea l inoculation of immunocompromised NOD/SCIO and nude mice, respectively. Tumors derived from PGRMC1-deplete cells grew slower than tumors from PGRMC1-intact cells. Mice harboring endometrial tumors were then given three treatments of vehicle (1:1 cremophor EL: ethanol + 0.9% saline) or chemotherapy [Paclitaxel (15 mg/kg, i.p.) followed after an interval of 30 minutes by CARBOplatin (SO mg/kg)] at five day intervals. In response to chemotherapy, tumor volume decreased approximately four-fold more in PGRMC1-deplete tumors when compared with PGRMC1 intact control tumors, suggesting that PGRMC1 promotes tumor cell viability during chemotherapeutic stress. In sum, these in vitro and in vivo findings demonstrate that PGRMC1 plays a prominent role in the growth and chemoresistance of human endometrial tumors.