Progesterone induces apoptosis by activation of caspase-8 and calcitriol via activation of caspase-9 pathways in ovarian and endometrial cancer cells in vitro.

Previously we have shown inhibition of endometrial cancer cell growth with progesterone and calcitriol. However, the mechanisms by which the two agents attenuate proliferation have not been well characterized yet. Herein, we investigated how progesterone and calcitriol induce apoptosis in cancer cells. DNA fragmentation was upregulated by progesterone and calcitriol in ovarian and endometrial cancer cells. Time-dependent treatment of ovarian cancer cells, ES-2, and TOV-21G with progesterone enhanced caspase -8 activity after 12 h, whereas OV-90, TOV-112D, HEC-1A, and HEC-59 cells showed increased activity after 24 h. Caspase 9 activity was increased in all cell lines after 24 h treatment with calcitriol. Pretreatment of cancer cells with a caspase-8 inhibitor (z-IETD-fmk) or caspase-9 inhibitor (Z-LEHD-fmk) significantly attenuated progesterone and calcitriol induced caspase-8 and caspase-9 expression, respectively. The expression of FasL, Fas, FAD, and pro-caspase-8, which constitute the death-inducing signaling complex (DISC), was upregulated in progesterone treated cancer cells. Knockdown of FAS or FADD with specific siRNAs significantly blocked progesterone-induced caspase-8. Cleavage of the BID was not affected by caspase-8 activation suggesting the absence of cross-talk between caspase-8 and caspase-9 pathways. Calcitriol treatment decreased mitochondrial membrane potential and increased the release of cancer cytochrome C. These findings indicate that progesterone induces apoptosis through activation of caspase-8 and calcitriol through caspase-9 activation in cancer cells. A combination of progesterone-calcitriol activates both extrinsic and intrinsic apoptotic pathways in cancer cells.

A Cell Line-based Immunohistochemical p53 Expression Pattern Control Panel.

TP53 gene mutations are known to manifest in distinct p53 immunohistochemical staining patterns; overexpression, wild-type, and null. These stratified staining patterns are routinely utilized in subtyping ovarian cancer subtypes. Three ovarian cancer cell lines were used in the construction of an immunohistochemical p53 expression pattern control panel that highlight respective TP53 mutation status. The cell line control panel sections demonstrated consistent clean and easily interpretable p53 immunohistochemical staining. Procured resection, biopsy, and cytologic specimens were submitted along with either standard control tissue or a p53 cell line control panel to pathologists of varying experience for interrater reliability analysis. Individual interrater reliability was near-perfect and was improved with the p53 cell line control panel when compared with the tissue control. The cell line control panel demonstrated decreased misinterpretation of null expression pattern as wild-type. Next-generation sequencing analysis was performed on the cell lines and select cases, in which there was discordance in p53 expression pattern interpretation. Next-generation sequencing analysis demonstrated low-frequency variant mutations in some cases in which there was reviewer discordance. This study suggests the addition of a p53 cell line expression pattern control panel could potentially increase p53 interpretation accuracy for ovarian cancer subtypes. We developed a cell line-based p53 control panel that has the potential to increase individual interrater reliability for p53 immunohistochemical expression pattern determination, support immunohistochemical optimization, and direct submission of difficult to interpret p53 staining cases to next-generation sequencing.

RNA interference screening identifies clathrin-B and cofilin-1 as mediators of MT1-MMP in endometrial cancer.

The matrix metalloproteinases (MMPs) are implicated in tumor invasion and metastasis. Given their multiple tumor promoting roles, MMPs are promising targets for the treatment of metastatic cancer. Using a siRNA library screen of 140 membrane trafficking genes, we identified 41 genes in HEC-1B and 36 in Ishikawa cancer cells that decreased metalloproteinases activity. The 16 genes common in both cancer cell lines that decreased MMPs activity are involved in cargo sorting, vesicle formation and vesicle recycling. The top two genes clathrin-B and cofilin-1 were chosen for post hoc functional studies. Higher expression of both genes was confirmed in cancer cells and knockdown with respective siRNAs inhibited their invasive potential and matrix metalloproteinases activity. Membrane Type 1- Matrix Metalloproteinase (MT1-MMP) is a master switch proteinase and regulator of invasion and metastasis. A marked decrease in MT1-MMP expression and activity was seen in clathrin-B and cofilin-1 knockdown cancer cells which was associated with a marked decreased expression of invadopodia formation proteins. Our results suggest that the decreased expression of clathrin-B and cofilin-1 decreases the expression of MT1-MMP and results in attenuation of MT1-MMP at the cell surface, thus inhibiting tumor cell invasion and metastasis.

Nitric Oxide Donor DETA/NO Inhibits the Growth of Endometrial Cancer Cells by Upregulating the Expression of RASSF1 and CDKN1A.

Nitric oxide (NO) is implicated in several biological processes, including cancer progression. At low concentrations, it promotes cell survival and tumor progression, and at high concentrations it causes apoptosis and cell death. Until now, the impact of NO donors has not been investigated on human endometrial tumors. Four cancer cell lines were exposed to different concentrations of DETA/NO for 24 to 120 h. The effects of DETA/NO on cell proliferation and invasion were determined utilizing MTS and Boyden chamber assays, respectively. The DETA/NO induced a dose and time-dependent reduction in cell viability by the activation of caspase-3 and cell cycle arrest at the G0/G1 phase that was associated with the attenuated expression of cyclin-D1 and D3. Furthermore, the reduction in the amount of CD133-expressing cancer stem-like cell subpopulation was observed following DETA/NO treatment of cells, which was associated with a decreased expression of stem cell markers and attenuation of cell invasiveness. To understand the mechanisms by which DETA/NO elicits anti-cancer effects, RNA sequencing (RNA-seq) was used to ascertain alterations in the transcriptomes of human endometrial cancer cells. RNA-seq analysis revealed that 14 of the top 21 differentially expressed genes were upregulated and seven were downregulated in endometrial cancer cells with DETA/NO. The genes that were upregulated in all four cell lines with DETA/NO were the tumor suppressors Ras association domain family 1 isoform A (RASSF1) and Cyclin-dependent kinase inhibitor 1A (CDKN1A). The expression patterns of these genes were confirmed by Western blotting. Taken together, the results provide the first evidence in support of the anti-cancer effects of DETA/NO in endometrial cancer.

Scutellaria baicalensis targets the hypoxia-inducible factor-1α and enhances cisplatin efficacy in ovarian cancer.

Hypoxia-inducible factor-1alpha (HIF-1α) is aberrantly upregulated in tumors and implicated in angiogenesis, metastasis, and drug resistance. Therefore, developing treatments that target HIF-1α may be a viable therapeutic approach. In Traditional Chinese Medicine (TCM), Scutellaria baicalensis (SB) is used for the treatment of cancer but the anti-cancer mechanisms are not known. We examined the effects of SB on HIF-1α expression in ovarian cancer (OC) cell lines grown under normoxic and hypoxic conditions. SB treatment attenuated HIF-1α expression in cancer cell lines. Treatment of cells with cycloheximide (CHX) reduced HIF-1α levels similar to cells treated with SB. Furthermore, SB-induced HIF-1α inhibition was abrogated by the proteasomal inhibitor MG132 and a lysosome inhibitor, chloroquine. Activation of PI3K/AKT and MAPK/ERK seen in OC cells was reduced with SB. Pretreatment of cells with LY294002 (phosphoinositide 3-kinase inhibitor) and PD98059 (mitogen-activated protein kinase inhibitor) reduced HIF-1α expression comparable to SB-treated cells. SB potentiated the anti-growth effects of cisplatin on OC cells by attenuating the expression of HIF-1α, ABCG1, and ABCG2. Taken together, the findings suggest that targeting HIF-1α with SB could be an effective treatment strategy for cancer and SB can improve the sensitivity of cancer cells to cisplatin, which is a major challenge in therapy for ovarian tumors.

TGF-ß Signaling in Cancer.

The transforming growth factor-ß (TGF-ß) is a family of structurally related proteins that comprises of TGF-ß, activins/inhibins, and bone morphogenic proteins (BMPs). Members of the TGF-ß family control numerous cellular functions including proliferation, apoptosis, differentiation, epithelial-mesenchymal transition (EMT), and migration. The first identified member, TGF-ß is implicated in several human diseases, such as vascular diseases, autoimmune disorders, and carcinogenesis. Activation of the TGF-ß receptor by its ligands induces the phosphorylation of serine/threonine residues and triggers phosphorylation of the intracellular effectors, SMADs. Upon activation, SMAD proteins translocate to the nucleus and induce transcription of their target genes, regulating several cellular functions. TGF-ß dysregulation has been implicated in carcinogenesis. In early stages of cancer, TGF-ß exhibits tumor suppressive effects by inhibiting cell cycle progression and promoting apoptosis. However, in late stages TGF-ß exerts tumor promoting effects, increasing tumor invasiveness, and metastasis. Furthermore, the TGF-ß signaling pathway communicates with other signaling pathways in a synergistic or antagonistic manner and regulates cellular functions. Elevated TGF-ß activity has been associated with poor clinical outcome. Given the pivotal role of TGF-ß in tumor progression, this pathway is an attractive target for cancer therapy. Several therapeutic tools such as TGF-ß antibodies, antisense oligonucleotides, and small molecules inhibitors of TGF-ß receptor-1 (TGF-ßR1) have shown immense potential to inhibit TGF-ß signaling. Finally, in the interest of developing future therapies, further studies are warranted to identify novel points of convergence of TGF-ß with other signaling pathways and oncogenic factors in the tumor microenvironment.

Nestin: A biomarker of aggressive uterine cancers.

OBJECTIVE: Evidence of potential prognostic and predictive value for nestin was investigated in well-annotated uterine cancers (UCs). METHODS: Nestin expression and previously-published biomarkers were evaluated by immunohistochemistry (IHC) in UC tissue microarrays. Biomarkers were categorized as low vs. high, and nestin was cut at 10% positive staining. Relationship between nestin and clinicopathologic factors, biomarkers and outcome were evaluated using exact/log-rank testing or logistic/Cox modeling. RESULTS: There were 323 eligible cases, 34% had advanced stage disease, 37% had type II disease, and 5% were carcinosarcomas. High nestin, observed in 19% of cases, was more common in advanced vs. early stage disease, type II cancers or uterine carcinosarcoma vs. type I cancers, grade 3 disease, positive lymphovascular space invasion (LVSI) and tumors >6cm (p<0.05). Nestin was inversely correlated with ER, PR and TFF3, and correlated with p53 and IMP3. Women with high vs. low nestin had worse progression-free survival (PFS) and cancer-specific survival overall, and worse PFS in the subset who received no adjuvant therapy or radiation, or had early stage, type I disease or tumors with both low and high ER, PR, TFF3, PTEN, p53 or IMP3. The relationship between nestin and PFS was independent of stage, LVSI and risk categorization but not type of UC. CONCLUSIONS: High nestin was more common in UCs with aggressive features and poor outcome. Nestin may represent a predictive biomarker for treatment selection for patients previously considered to be lower risk and a candidate for no or radiation-based adjuvant therapy, and compliment ER/PR testing.

Progestins inhibit calcitriol-induced CYP24A1 and synergistically inhibit ovarian cancer cell viability: An opportunity for chemoprevention.

OBJECTIVES: Previously we have shown in endometrial cells that progesterone (P4) and calcitriol (CAL, 1,25(OH)2D3) synergistically promote apoptosis and that progestins induce expression of the vitamin D receptor. In the current study we examined the progestin/vitamin D combination in ovarian cells and searched for other progestin-related effects on vitamin D metabolism that may underlie the novel interaction between progestins and vitamin D, including whether progestins inhibit CYP24A1, the enzyme that renders CAL inactive. METHODS: We investigated the impact of P4 on CAL-induced CYP24A1 expression in cancer cell lines expressing progesterone receptors (PRs), [OVCAR-5, OVCAR-3-PGR (PR-transfected OVCAR-3 ovarian line), and T47D-WT, T47D-A and T47D-B (breast lines expressing PRs or individual PR isoforms)] or lines that do not express PRs (OVCAR-3 and T47D-Y). We examined CYP24A1 expression using RT-PCR and western blotting, and apoptosis by TUNEL. We also investigated P4 inhibition of Cyp24a1 in ovaries from CAL-treated mice. RESULTS: CAL treatment induced CYP24A1 expression. When co-treated with P4, cell lines expressing PRs showed marked inhibition of CYP24A1 expression (p<0.001), along with increased apoptosis (p<0.01); cells not expressing PRs did not. Mouse ovaries showed a significant reduction in CAL-induced Cyp24a1 mRNA (p<0.001) and protein (p<0.01) in response to P4. CONCLUSIONS: We show for the first time that progestins and vitamin D synergistically reduce cell viability and induce apoptosis in ovarian cells and that progestins PR-dependently inhibit CAL-induced CYP24A1, thus extending CAL activity. The combination of progestins and vitamin D deserves further consideration as a strategy for inhibiting ovarian carcinogenesis.

PHARMACOLOGICAL ASSESSMENT OF HISPIDULIN - A NATURAL BIOACTIVE FLAVONE.

Hispidulin is well-known natural bioactive flavone on behalf of its pharmacological aspects. This review contains data on isolation, synthetic methodology, pharmacokinetics and bioactivities of hispidulin. The article provides a critical assessment of present knowledge about hispidulin with some clear conclusions, perspectives and directions for future research in potential applications.

Inhibition of Transforming Growth Factor-ß (TGF-ß) Signaling by Scutellaria baicalensis and Fritillaria cirrhosa Extracts in Endometrial Cancer.

Transforming growth factor-ß (TGF-ß), regulates cell proliferation, angiogenesis, metastasis, and is an inducer of epithelial-mesenchymal transition (EMT). Cancer cells exhibit activated TGF-ß/SMAD signaling pathway and its inhibition is an attractive strategy for cancer treatment. The Chinese Herbs Scutellaria baicalensis (SB) and Fritillaria cirrhosa (FC) have been shown to be beneficial to cancer patients, but the mechanisms by which the extracts of two herbs elicit the beneficial effects are unclear. In this study, we have used human endometrial cancer cells to assess the anticancer efficacy of SB and FC on TGF-ß signaling pathway components. SB and FC treatment of cancer cells resulted in a significant decrease in expression of TGF-ß isoforms, TGF-ß receptors, and SMADs. Both herbs effectively inhibited basal and TGF-ß1-induced cancer cell proliferation and invasion, which was accompanied with abrogation of Snail, Slug, matrix metalloproteinases (MMPs), αvß3 integrin, focal adhesion kinase (FAK), and p-FAK expression. An inhibitor of TGF-ßRI blocked TGF-ß1-induced cell invasion and significantly diminished antitumor effects of SB and FC. These results suggest that SB and FC block endometrial cancer growth by downregulating TGF-ß/SMAD signaling pathway.

The Chinese herbs Scutellaria baicalensis and Fritillaria cirrhosa target NFκB to inhibit proliferation of ovarian and endometrial cancer cells.

The herbs Scutellaria baicalensis (SB) and Fritillaria cirrhosa (FC) are widely used in Chinese medicine to treat several aliments and as an adjuvant to chemotherapy of lung cancer. No information is available regarding the two herbs' influence on ovarian and endometrial cancer. To fill this data gap we compared cell growth responses to SB and FC in ovarian and endometrial cancer cell lines. Dose-dependent cell growth inhibition was observed following higher doses in all cell lines while lower doses stimulated growth in only endometrial cell lines. Higher doses of SB and FC significantly decreased cell growth on soft agar and decreased the invasive potential of cancer cells. Treatment of cells with both herbs resulted in activation of caspase-3, G0 /G1 phase cell cycle arrest, downregulation of cyclins D1 and D3 and induction of p27. Both herbs decreased NFκB DNA binding, reduced expression of phosphorylated IκBα, abrogated NFκB activation, and downregulated NFκB-regulated metastasis-promoting proteins in cancer cells. Furthermore, knockdown of NFκB attenuated SB- and FC-induced cell growth inhibition. These results suggest that inhibition of NFκB activation may be an important mechanism for growth suppression by SB and FC. Data indicate that these herbs may represent a new source of agents for NFκB inhibition in cancer therapy.

PHARMACOLOGICAL ASSESSMENT OF HISPIDULIN--A NATURAL BIOACTIVE FLAVONE.

Hispidulin is well-known natural bioactive flavone on behalf of its pharmacological aspects. This review contains data on isolation, synthetic methodology, pharmacokinetics and bioactivities of hispidulin. The article provides a critical assessment of present knowledge about hispidulin with some clear conclusions, perspectives and directions for future research in potential applications.

Progesterone and calcitriol attenuate inflammatory cytokines CXCL1 and CXCL2 in ovarian and endometrial cancer cells.

Cytokines/chemokines are key players in cancer-related inflammation. Increasing evidence suggests that chemokines produced by tumor cells are the mediators of metastasis. Thus, agents that can downregulate chemokines expression have potential against cancer metastasis. We have previously shown inhibition of ovarian and endometrial cancer cell growth with progesterone and calcitriol. In the present study, we evaluated the effect of these two agents on the expression of inflammatory genes. Using a RT-PCR array of inflammatory cytokines/chemokines and their receptors, we found a marked attenuation of CXCL1 and CXCL2 (GRO-α and -ß) in cancer cells by both treatments. Knockdown of NFκB resulted in a reduced expression of CXCL1 and CXCL2 and the inhibitory effect of progesterone and calcitriol on the expression of chemokines was abrogated in NFκB-silenced cancer cells. Silencing of IκBα increased the expression of CXCL1 and CXCL2 in cancer cells, which can be attributed to the increased activation of NFκB-p65, caused by the lack of its inhibitor. Progesterone and calcitriol-induced inhibition was abolished in IκBα-knockdown cells. Our results demonstrate that suppression of IκBα phosphorylation by progesterone and calcitriol contributes to the reduced expression of CXCL1 and CXCL2. Downregulation of CXCL1 and CXCL2 was associated with a marked inhibition of metastasis-promoting genes. Overall, our results indicate that progesterone and calcitriol inhibit IκBα phosphorylation, NFκB activation, and the expression of NFκB regulated metastasis promoting genes. These results provide attractive data for the possible use of progesterone and calcitriol in the management of endometrial and ovarian tumors.

Progesterone inhibits growth and induces apoptosis in cancer cells through modulation of reactive oxygen species.

OBJECTIVE: Progesterone (P4) has been implicated as a protective factor for ovarian and endometrial cancers, yet little is known about its mechanism of action. We have shown apoptosis in ovarian and endometrial cancer cells with high doses of P4. Increased generation of reactive oxygen species (ROS) and an altered redox status have long been observed in cancer cells. The goal of this study was to assess the effect of P4 on cell growth, ROS generation, oxidative stress markers, and the expression of antioxidant proteins. METHODS: All experiments were performed in vitro using cancer cell lines. Cell proliferation was determined using MTS proliferation assay. Production of ROS in cells was measured with the ROS indicator dye, aminophenyl fluorescein. Alterations in expression of antioxidant and apoptotic proteins were assessed by Western blotting. RESULTS: The exposure of ovarian and endometrial cancer cell cultures to various doses of P4 caused a dose-dependent decrease in cell viability and the activation of caspase-3. Levels of ROS, markers of oxidative stress, and antioxidant proteins were elevated in cancer cells compared to normal cells and a marked decrease in their expression was seen following P4 treatment. In cancer cells, ROS was elevated while p-53 expression was low. P4 exposure of cells resulted in increased p-53 and BAX and decreased BCL-2 expression. CONCLUSIONS: The data indicates that P4 has antioxidant effects. It alleviates ROS stress and causes apoptosis by upregulating proapoptotic (p-53 and BAX) and decreasing antiapoptotic (BCL-2) gene expression in cancer cells. These findings could have potential therapeutic implications.

Curcumin suppresses constitutive activation of STAT-3 by up-regulating protein inhibitor of activated STAT-3 (PIAS-3) in ovarian and endometrial cancer cells.

Signal transducer and activator of transcription-3 (STAT-3) is constitutively activated in ovarian and endometrial cancers and is implicated in uncontrolled cell growth. Thus, its disruption could be an effective approach to control tumorigenesis. Curcumin is a dihydroxyphenolic compound, with proven anti-cancer efficacy in various cancer models. We examined the anti-tumor mechanism of curcumin on STAT-3 and on the negative regulators of STAT-3, including suppressors of cytokine signaling proteins (SOCS-1 and SOCS-3), protein inhibitors of activated STAT (PIAS-1 and PIAS-3), and SH2 domain-containing phosphatases (SHP-1 and SHP-2) in ovarian and endometrial cancer cell lines. Treatment of cancer cells with curcumin induced a dose- and time-dependent decrease of constitutive IL-6 expression and of constitutive and IL-6-induced STAT-3 phosphorylation, which is associated with decreased cell viability and increased cleavage of caspase-3. The inhibition of STAT-3 activation by curcumin was reversible, and phosphorylated STAT-3 levels returned to control levels 24 h after curcumin removal. Compared to normal cells baseline expression of SOCS-3 was high in cancer cells and a marked decrease in SOCS-3 expression was seen following curcumin treatment. Overexpression of SOCS-3 in curcumin-treated cells increased expression of phosphorylated STAT-3 and resulted in increased cell viability. Normal ovarian and endometrial cells exhibited high expression of PIAS-3 protein, whereas in cancer cells the expression was greatly reduced. Curcumin increased PIAS-3 expression in cancer cells. Of significance, siRNA-mediated knockdown of PIAS-3 overcomes the inhibitory effect of curcumin on STAT-3 phosphorylation and cell viability. In conclusion, curcumin suppresses JAK-STAT signaling via activation of PIAS-3, thus attenuating STAT-3 phosphorylation and tumor cell growth.

Progesterone-Calcitriol Combination Enhanced Cytotoxicity of Cisplatin in Ovarian and Endometrial Cancer Cells In Vitro.

: Initially, patients that respond to cisplatin (DDP) treatment later relapse and develop chemoresistance. Agents that enhance DDP effectiveness will have a significant impact on cancer treatment. We have shown pronounced inhibitory effects of the progesterone-calcitriol combination on endometrial and ovarian cancer cell growth. Here, we examined whether and how progesterone-calcitriol combination potentiates DDP anti-tumor effects in cancer cells. Ovarian and endometrial cancer cells treated with various concentrations of DDP showed a concentration-dependent decrease in cell proliferation. Concurrent treatment of cells with DDP and progesterone-calcitriol ombination potentiated anticancer effects of DDP compared to DDP-calcitriol, or DDP-progesterone treated groups. The anticancer effects were mediated by increased caspase-3, BAX, and decreased BCL2 and PARP-1 expression in DDP and progesterone-calcitriol combination-treated cells. Stimulation of the PI3K/AKT and MAPK/ERK pathways seen in cancer cells was reduced in DDP-progesterone-calcitriol treated cells. Pretreatment of cells with specific inhibitors further diminished AKT and ERK expression. Furthermore, progesterone-calcitriol potentiated the anti-growth effects of DDP on cancer cells by attenuating the expression of SMAD2/3, multidrug resistance protein- 1 (MDR-1), and ABC transporters (ABCG1, and ABCG2), thereby impeding the efflux of chemo drugs from cancer cells. These results suggest a potential clinical benefit of progesterone-calcitriol combination therapy when used in combination with DDP.

TGF-ß signaling proteins and CYP24A1 may serve as surrogate markers for progesterone calcitriol treatment in ovarian and endometrial cancers of different histological types.

BACKGROUND: Strategies are needed to coordinately block drivers and induce suppressors of cancer to reduce incidence and improve outcomes for individuals with inherited or acquired risk. We previously reported the chemopreventive and therapeutic efficacy of the combination of progestin and calcitriol in transformed and malignant endometrioid endometrial cancer (EC) and in ovarian cancer models involving attenuated expression of TGF-ß signaling proteins and progestin-mediated inhibition of calcitriol-induced CYP24A1 expression. This study aims to expand the applications for this combination to other subtypes of endometrial and ovarian cancers, including those with mutations in ARID1A or PIK3CA, DNA mismatch repair (MMR) deficiency or BRCA1 null status. METHODS: Ovarian and EC cell lines of different histotypes were cultured with either progesterone, calcitriol, or the combination of progesterone and calcitriol for 3 or 5 days. The end points for this in vitro investigation included assessments of cell growth by (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) (MTS) assays and the expression of TGF-ß ligands, receptors, SMAD proteins and CYP24A1 by western blotting. RESULTS: Treatment of ovarian clear cell carcinoma, endometrioid carcinoma, papillary serous adenocarcinoma, BRCA1 null, and DNA MMR deficient EC cell lines with progesterone alone or in combination with calcitriol inhibited cell growth and expression of TGF-ß1, TGF-ß2, TGF-Rß1, TGF-ßR2, pSMAD2/3 and CYP24A1. Expression of TGF-ßR3, SMAD-4, progesterone receptor (PR) and vitamin-D receptor (VDR) was not altered in any cell line tested except, ES-2, where VDR expression was upregulated in response to treatment. CONCLUSIONS: These results suggest that progesterone alone and progesterone-calcitriol combination have broad application in both chemopreventive and therapeutic settings that merit further development in a wide variety of ovarian and ECs, including those derived from germline or somatic mechanisms. Moreover, our data suggest that TGF-ß signaling proteins and CYP24A1 may be effective surrogate markers indicative of treatment response.

Beta-catenin mediates alteration in cell proliferation, motility and invasion of prostate cancer cells by differential expression of E-cadherin and protein kinase D1.

We have previously demonstrated that Protein Kinase D1 (PKD1) interacts with E-cadherin and is associated with altered cell aggregation and motility in prostate cancer (PC). Because both PKD1 and E-cadherin are known to be dysregulated in PC, in this study we investigated the functional consequences of combined dysregulation of PKD1 and E-cadherin using a panel of human PC cell lines. Gain and loss of function studies were carried out by either transfecting PC cells with full-length E-cadherin and/or PKD1 cDNA or by protein silencing by siRNAs, respectively. We studied major malignant phenotypic characteristics including cell proliferation, motility, and invasion at the cellular level, which were corroborated with appropriate changes in representative molecular markers. Down regulation or ectopic expression of either E-cadherin or PKD1 significantly increased or decreased cell proliferation, motility, and invasion, respectively, and combined down regulation cumulatively influenced the effects. Loss of PKD1 or E-cadherin expression was associated with increased expression of the pro-survival molecular markers survivin, beta-catenin, cyclin-D, and c-myc, whereas overexpression of PKD1 and/or E-cadherin resulted in an increase of caspases. The inhibitory effect of PKD1 and E-cadherin on cell proliferation was rescued by coexpression with beta-catenin, suggesting that beta-catenin mediates the effect of proliferation by PKD1 and E-cadherin. This study establishes the functional significance of combined dysregulation of PKD1 and E-cadherin in PC and that their effect on cell growth is mediated by beta-catenin.

Protein kinase D1 (PKD1) influences androgen receptor (AR) function in prostate cancer cells.

Protein kinase D1 (PKD1), founding member of PKD protein family, is down-regulated in advanced prostate cancer (PCa). We demonstrate that PKD1 and androgen receptor (AR) are present as a protein complex in PCa cells. PKD1 is associated with a transcriptional complex which contains AR and promoter sequence of the Prostate Specific Antigen (PSA) gene. Ectopic expression of wild type PKD1 and the kinase dead mutant PKD1 (K628W) attenuated the ligand-dependent transcriptional activation of AR in prostate cancer cells and yeast cells indicating that PKD1 can affect AR transcription activity, whereas knocking down PKD1 enhanced the ligand-dependent transcriptional activation of AR. Co-expression of kinase dead mutant with AR significantly inhibited androgen-mediated cell proliferation in both LNCaP and DU145 PC cells. Our data demonstrate for the first time that PKD1 can influence AR function in PCa cells.

Progesterone and calcitriol reduce invasive potential of endometrial cancer cells by targeting ARF6, NEDD9 and MT1-MMP.

Previously, we have demonstrated that progesterone and calcitriol synergistically inhibit growth of endometrial and ovarian cancer by enhancing apoptosis and causing cell cycle arrest. Metastasis is the main reason of mortality in cancer patients. Activation of ADP-Ribosylation Factor 6 (ARF6), Neural Precursor cell expressed Developmentally Downregulated 9 (NEDD9), and Membrane-Type-1 Matrix Metalloproteinase (MT1-MMP) have been implicated in promoting tumor growth and metastasis. We examined the effects of progesterone, calcitriol and progesterone-calcitriol combination on metastasis promoting proteins in endometrial cancer. Expression of ARF6, NEDD9, and MT1-MMP was enhanced in advanced-stage endometrial tumors and in cancer cell lines compared to normal tissues and immortalized EM-E6/E7-TERT endometrial epithelial cells. Knockdown of these proteins significantly inhibited the invasiveness of the cancer cells. The expression levels of all three proteins was reduced with progesterone and progesterone-calcitriol combination treatment, whereas calcitriol alone showed no effect on their expression but moderately decreased MT1-MMP activity. Fluorescence microscopy showed membrane expression of MT1-MMP in vehicle and calcitriol-treated endometrial cancer cells. However, progesterone and calcitriol-progesterone combination treatment revealed MT1-MMP in the cytoplasm. Furthermore, progesterone and calcitriol reduced the activity of MT1-MMP, MMP-9, and MMP-2. In addition, invadopodia regulatory proteins were attenuated in both progesterone and progesterone-calcitriol combination treated cells as well as in MT1-MMP knockdown cells. Thus, targeting the aberrant MT1-MMP signaling with progesterone-calcitriol may be a novel approach to impede MT1-MMP mediated cancer dissemination and may have therapeutic benefits for endometrial cancer patients.