Secreted STIP1 stimulates cell proliferation of ovarian cancer through SMAD signaling pathways
Ontology highlight
ABSTRACT: Stress-induced phosphoprotein 1 (STIP1) is a co-chaperone that regulates other chaperone proteins that was recently shown to be secreted by ovarian cancer cells to induce cell proliferation. In this study, we found that STIP1 induced the phosphorylation of endogenous SMAD1/5, and knockdown of SMAD1/4/5 blocked STIP1-activated ID3 expression. Inhibition of ALK2, a serine/threonine kinase receptor, with siRNA or the specific inhibitor LDN193189, blocked STIP1-induced phosphorylation of SMAD1/5 and inhibited STIP1-related cell proliferation. The signaling pathway was found to involve binding of secreted STIP1 to ALK2, phosphorylation of SMAD, and activation of ID3 to induce cell proliferation was identified not only by in vitro immunofluorescent microscopy and biochemical identification of complex formation, but also by in vivo immunohistochemical analyses of ovarian cancer tissues. MDAH2774 cell treated with rhSTIP1 MDAH2774 cell treated without rhSTIP1 MDAH2774 cell treated with rhSTIP1-2 MDAH2774 cell treated without rhSTIP1-2
Project description:Stress-induced phosphoprotein 1 (STIP1) is a co-chaperone that regulates other chaperone proteins that was recently shown to be secreted by ovarian cancer cells to induce cell proliferation. In this study, we found that STIP1 induced the phosphorylation of endogenous SMAD1/5, and knockdown of SMAD1/4/5 blocked STIP1-activated ID3 expression. Inhibition of ALK2, a serine/threonine kinase receptor, with siRNA or the specific inhibitor LDN193189, blocked STIP1-induced phosphorylation of SMAD1/5 and inhibited STIP1-related cell proliferation. The signaling pathway was found to involve binding of secreted STIP1 to ALK2, phosphorylation of SMAD, and activation of ID3 to induce cell proliferation was identified not only by in vitro immunofluorescent microscopy and biochemical identification of complex formation, but also by in vivo immunohistochemical analyses of ovarian cancer tissues.
Project description:Stress-induced phosphoprotein 1 (STIP1), a co-chaperone that organizes other chaperones- heat shock proteins (HSP), was recently shown to be secreted by human ovarian cancer cells to induce cell proliferation. In neuronal tissues, binding to prion protein was required for STIP1 to activate the ERK (extracellular regulated MAP kinase) signaling pathways. However, in this study, we found that STIP1 stimulated cell proliferation of ovarian cancer via a bone morphogenetic protein (BMP) signaling pathway, not through the prion-ERK pathway. The STIP1 binding to a BMP receptor, ALK2 (activin A receptor, type II-like kinase 2), was necessary and sufficient to stimulate cancer cell proliferation. The binding of STIP1 to ALK2 activated the SMAD signaling pathway, leading to transcriptional activation of ID3 (inhibitor of DNA binding 3) that promotes cell proliferation. In conclusion, ovarian cancer tissues secrete STIP1 into the local environment and eventually into blood circulation of patients. In an autocrine and/or paracrine fashion, secreted STIP1 stimulates cancer cell proliferation by binding to ALK2 and activating the SMAD-ID3 signaling pathways. Elucidation of the mechanism by which STIP1 stimulates cancer cell proliferation may pave the way for developing novel therapeutic strategies for treatment of ovarian cancer. SKOV3 cell,treated without rhSTIP1 SKOV3 cell,treated with rhSTIP1 SKOV3 cell,treated without rhSTIP1-2 SKOV3 cell,treated with rhSTIP1-2
Project description:Stress-induced phosphoprotein 1 (STIP1), a co-chaperone that organizes other chaperones- heat shock proteins (HSP), was recently shown to be secreted by human ovarian cancer cells to induce cell proliferation. In neuronal tissues, binding to prion protein was required for STIP1 to activate the ERK (extracellular regulated MAP kinase) signaling pathways. However, in this study, we found that STIP1 stimulated cell proliferation of ovarian cancer via a bone morphogenetic protein (BMP) signaling pathway, not through the prion-ERK pathway. The STIP1 binding to a BMP receptor, ALK2 (activin A receptor, type II-like kinase 2), was necessary and sufficient to stimulate cancer cell proliferation. The binding of STIP1 to ALK2 activated the SMAD signaling pathway, leading to transcriptional activation of ID3 (inhibitor of DNA binding 3) that promotes cell proliferation. In conclusion, ovarian cancer tissues secrete STIP1 into the local environment and eventually into blood circulation of patients. In an autocrine and/or paracrine fashion, secreted STIP1 stimulates cancer cell proliferation by binding to ALK2 and activating the SMAD-ID3 signaling pathways. Elucidation of the mechanism by which STIP1 stimulates cancer cell proliferation may pave the way for developing novel therapeutic strategies for treatment of ovarian cancer.
Project description:Epigenetically silenced Ink4a-Arf locus is activated by loss of H3K27me3 in cellular senescence, where secreted factor expression is also involved. Here we analyzed epigenome and transcriptome alteration during Ras-induced senescence using mouse embryonic fibroblast (MEF). Seventeen genes with H3K27me3 loss and H3K4me3 gain showed marked upregulation, including p16Ink4a and Bmp2, a secreted factor for BMP/SMAD signal. Smad6, specific BMP/SMAD pathway inhibitor, was identified as the only one gene showing de novo H3K27 trimethylation with H3K4me3, resulting in strong repression. Ras-activated cells senesced with SMAD1/5/8 phosphorylation, and they escaped from senescence with decreased SMAD1/5/8 phosphorylation when introducing Smad6 or knocking-down Bmp2.
Project description:PD-0332991 is a selective inhibitor of the CDK4/6 kinases with the ability to block retinoblastoma (Rb) phosphorylation in the low nanomolar range. Here we investigate the role of CDK4/6 inhibition in human ovarian cancer. We examined the effects of PD-0332991 on proliferation, cell-cycle, apoptosis, and Rb phosphorylation using a panel of 40 established human ovarian cancer cell lines. Molecular markers for response prediction, including p16 and Rb, were studied using gene expression profiling, Western blot, and arrayCGH. Multiple drug effect analysis was used to study interactions with chemotherapeutic drugs. Expression of p16 and Rb was studied using immunohistochemistry in a large clinical cohort ovarian cancer patients. Concentration-dependent anti-proliferative effects of PD-0332991were seen in all ovarian cancer cell lines, but varied significantly between individual lines. Rb proficient cell lines with low p16 expression were most responsive to CDK4/6 inhibition. Copy number variations of CDKN2A, Rb, CCNE1, and CCND1 were associated with response to PD-0332991. CDK4/6 inhibition induced G0/G1 cell cycle arrest, blocked Rb phosphorylation in a concentration and time dependent manner, and enhanced the effects of chemotherapy. Rb proficiency with low p16 expression was seen in 97/262 (37%) of ovarian cancer patients and associated with adverse clinical outcome (progression free survival, adjusted relative risk 1.49, 95%CI 0.99-2.22, p =0.054). PD-0332991 shows promising biologic activity in ovarian cancer cell lines. Assessment of Rb and p16 expression may help select patients most likely to benefit from CDK4/6 inhibition in ovarian cancer. Gene expression of 40 individual ovarian cell lines relative to an ovarian cell line reference mix containing equal amounts of 41 ovarian cell lines (including OCC-1 which was later identified as originating from mouse). The expression data was correllated with cell line growth response to CDK 4/6 inhibitor PD-0332991 to identify genes associated with drug sensitivity and resistance.
Project description:The tightly controlled BMP-Smad1 pathway is essential for embryonic development and postnatal tissue homeostasis. Dysfunction of BMP-Smad1 signaling also leads to tumor development such as juvenile polyposis and Cowden syndromes and various tumors in mouse models, with unknown pathological mechanisms. Here we establish a link between the BMP-Smad pathway and the prominent tumor suppressor Atm-p53 pathway. We identify activated nuclear Smad1 as an Atm substrate under genotoxic stress. Atm-mediated Smad1 S239 phosphorylation disrupts Smad1 interaction with protein phosphatase PPM1A and enhances Smad1 activation and up-regulation, which not only turns on target genes including Cdk1nc but also interacts with p53 and inhibits Mdm2-mediated p53 ubiquitination, leading to p53 stabilization. Functionally, Smad1 acts like a tumor suppressor in DNA damage response, cell transformation and tumorigenesis in a p53-dependent manner. Sequencing of the gastric cancer samples revealed that Smad1 is frequently mutated, with S239 as mutational hotspot. This study thus establishes the BMP-Smad1 pathway as an integral part of DNA damage response, which can suppresses tumorigenesis via p53. Transformed MEFs (Smad1f/f, Smad1f/f Cre) treated with 50ng/ml BMP2, 1 ug/ml doxorubincin, or both for different periods of time. The mRNA levels of all genes were compared using microarray analysis.
Project description:NRAS-mutant melanoma is currently a challenge to treat. This is due to an absence of inhibitors directed against NRAS, along with acquired and adaptive resistance of this tumor type to inhibitors in the MAPK pathway. Inhibitors to MEK (mitogen-activated protein kinase kinase) have shown some promise for this tumor type. In this work we explored the use of MEK inhibitors for NRAS-mutant melanoma, and at the same time investigated the impact of the brain micro-environment, specifically astrocytes, on the response of a melanoma brain metastatic cell line to MEK inhibition. This led to the surprising finding that astrocytes enhance the sensitivity of melanoma tumors to MEK inhibitors (MEKi). We show that MEKi cause an upregulation of the transcription factor ID3, but this is blocked by conditioned media from astrocytes. We show that silencing ID3 enhances the sensitivity of melanoma to MEK inhibitors, thus mimicking the effect of the brain microenvironment. Moreover, we report that ID3 is a client protein of the chaperone HSP70, and that HSP70 inhibition causes ID3 to misfold and accumulate in a detergent-insoluble fraction in cells. We show that HSP70 inhibitors synergize with MEK inhibitors against NRAS-mutant melanoma, and that this combination significantly enhances the survival of mice in two different models of NRAS-mutant melanoma. These studies highlight ID3 as a mediator of adaptive resistance, and support the combined use of MEK and HSP70 inhibitors for the therapy of NRAS-mutant melanoma.
Project description:PD-0332991 is a selective inhibitor of the CDK4/6 kinases with the ability to block retinoblastoma (Rb) phosphorylation in the low nanomolar range. Here we investigate the role of CDK4/6 inhibition in human ovarian cancer. We examined the effects of PD-0332991 on proliferation, cell-cycle, apoptosis, and Rb phosphorylation using a panel of 40 established human ovarian cancer cell lines. Molecular markers for response prediction, including p16 and Rb, were studied using gene expression profiling, Western blot, and arrayCGH. Multiple drug effect analysis was used to study interactions with chemotherapeutic drugs. Expression of p16 and Rb was studied using immunohistochemistry in a large clinical cohort ovarian cancer patients. Concentration-dependent anti-proliferative effects of PD-0332991were seen in all ovarian cancer cell lines, but varied significantly between individual lines. Rb proficient cell lines with low p16 expression were most responsive to CDK4/6 inhibition. Copy number variations of CDKN2A, Rb, CCNE1, and CCND1 were associated with response to PD-0332991. CDK4/6 inhibition induced G0/G1 cell cycle arrest, blocked Rb phosphorylation in a concentration and time dependent manner, and enhanced the effects of chemotherapy. Rb proficiency with low p16 expression was seen in 97/262 (37%) of ovarian cancer patients and associated with adverse clinical outcome (progression free survival, adjusted relative risk 1.49, 95%CI 0.99-2.22, p =0.054). PD-0332991 shows promising biologic activity in ovarian cancer cell lines. Assessment of Rb and p16 expression may help select patients most likely to benefit from CDK4/6 inhibition in ovarian cancer.
Project description:Primary objectives: To ascertain whether orally delivered Simvastatin affects levels of apoptosis, proliferation and bone morphogenetic protein pathway activation in colorectal cancer in humans.
Primary endpoints: Levels of BMP2 and 4 and phospho-Smad1 in surgical resection specimens.levels of apoptosis and proliferation in surgical resection specimenslevels of angiogenesis in surgical resection specimens