CDK5 positively regulates Notch1 signaling in pancreatic cancer cells by phosphorylation.
Ontology highlight
ABSTRACT:
SUBMITTER: Chu Q
PROVIDER: S-EPMC8178504 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:BackgroundActivated Cdk5 regulates a number of processes during nervous system formation, including neuronal differentiation, growth cone stabilization, and axonal growth. Cdk5 phosphorylates its downstream substrates located in axonal growth cones, where the highly expressed c-Jun N-terminal kinase (JNK)-interacting protein1 (JIP1) has been implicated as another important regulator of axonal growth. In addition, stringent control of the level of intracellular domain of Notch1 (Notch1-IC) plays a regulatory role in axonal outgrowth during neuronal differentiation. However, whether Cdk5-JIP1-Notch1 cooperate to regulate axonal outgrowth, and the mechanism of such joint contribution to this pathway, is presently unknown, and here we explore their potential interaction.ResultsOur interactome screen identified JIP1 as an interactor of p35, a Cdk5 activator, and we sought to explore the relationship between Cdk5 and JIP1 on the regulation of axonal outgrowth. We demonstrate that JIP1 phosphorylated by Cdk5 at Thr205 enhances axonal outgrowth and a phosphomimic JIP1 rescues the axonal outgrowth defects in JIP1-/- and p35-/- neurons. Axonal outgrowth defects caused by the specific increase of Notch1 in JIP1-/- neurons are rescued by Numb-mediated inhibition of Notch1. Finally, we demonstrate that Cdk5 phosphorylation of JIP1 further amplifies the phosphorylation status of yet another Cdk5 substrate E3-ubiquitin ligase Itch, resulting in increased Notch1 ubiquitination.ConclusionsOur findings identify a potentially critical signaling axis involving Cdk5-JIP1-Itch-Notch1, which plays an important role in the regulation of CNS development. Future investigation into the way this pathway integrates with additional pathways regulating axonal growth will further our knowledge of normal central nervous system development and pathological conditions.
| S-EPMC9115922 | biostudies-literature
Project description:BackgroundProfound chemoresistance remains an intractable obstacle in pancreatic cancer treatment. Pancreatic cancer stem cells (CSCs) and the ubiquitous hypoxic niche have been proposed to account for drug resistance. However, the mechanism involved requires further exploration. This study investigated whether the hypoxic niche enhances gemcitabine-induced stemness and acquired resistance in pancreatic cancer cells by activating the AKT/Notch1 signaling cascade. The therapeutic effects of blockading this signaling cascade on gemcitabine-enriched CSCs were also investigated.MethodsThe expression levels of CSC-associated markers Bmi1 and Sox2 as well as those of proteins involved in AKT/Notch1 signaling were measured by Western blot analysis. The expression level of the pancreatic CSC marker CD24 was measured by flow cytometry. Change in gemcitabine sensitivity was evaluated by the MTT assay. The ability of sphere formation was tested by the sphere-forming assay in stem cell medium. The ability of migration and invasion was detected by the transwell migration/invasion assay. A mouse xenograft model of pancreatic cancer was established to determine the effect of Notch1 inhibition on the killing effect of gemcitabine in vivo. The ability of metastasis was investigated by an in vivo lung metastasis assay.ResultsGemcitabine promoted pancreatic cancer cell stemness and associated malignant phenotypes such as enhanced migration, invasion, metastasis, and chemoresistance. The AKT/Notch1 signaling cascade was activated after gemcitabine treatment and mediated this process. Blockading this pathway enhanced the killing effect of gemcitabine in vivo. However, supplementation with hypoxia treatment synergistically enhanced the AKT/Notch1 signaling pathway and collaboratively promoted gemcitabine-induced stemness.ConclusionsThese findings demonstrate a novel mechanism of acquired gemcitabine resistance in pancreatic cancer cells through induction of stemness, which was mediated by the activation of AKT/Notch1 signaling and synergistically aggravated by the ubiquitous hypoxic niche. Our results might provide new insights for identifying potential targets for reversing chemoresistance in patients with pancreatic cancer.
| S-EPMC6263055 | biostudies-literature
Project description:Tumorigenesis is a multistep process involving co-operation between several deregulated oncoproteins. In this study, we unravel previously unrecognized interactions and crosstalk between Pim kinases and the Notch signaling pathway, with implications for both breast and prostate cancer. We identify Notch1 and Notch3, but not Notch2, as novel Pim substrates and demonstrate that for Notch1, the serine residue 2152 is phosphorylated by all three Pim family kinases. This target site is located in the second nuclear localization sequence (NLS) of the Notch1 intracellular domain (N1ICD), and is shown to be important for both nuclear localization and transcriptional activity of N1ICD. Phosphorylation-dependent stimulation of Notch1 signaling promotes migration of prostate cancer cells, balances glucose metabolism in breast cancer cells, and supports in vivo growth of both types of cancer cells on chick embryo chorioallantoic membranes. Furthermore, Pim-induced growth of orthotopic prostate xenografts in mice is associated with enhanced nuclear Notch1 activity. Finally, simultaneous inhibition of Pim and Notch abrogates the cellular responses more efficiently than individual treatments, opening up new vistas for combinatorial cancer therapy.
| S-EPMC5190019 | biostudies-literature
Project description:The bromodomain and extraterminal (BET) proteins are epigenetic "readers" of acetylated histones in chromatin and have been identified as promising therapeutic targets in diverse cancers. However, it remains unclear how individual family members participate in cancer progression and small molecule inhibitors such as JQ1 can target functionally independent BET proteins. Here, we report a signaling pathway involving BRD4 and the ligand/receptor pair Jagged1/Notch1 that sustains triple-negative breast cancer migration and invasion. BRD4, but not BRD2 or BRD3, regulated Jagged1 expression and Notch1 signaling. BRD4-selective knockdown suppressed Notch1 activity and impeded breast cancer migration and invasion. BRD4 was required for IL6-stimulated, Notch1-induced migration and invasion, coupling microenvironment inflammation with cancer propagation. Moreover, in patients, BRD4 and Jagged1 expression positively correlated with the presence of distant metastases. These results identify a BRD4/Jagged1/Notch1 signaling pathway that is critical for dissemination of triple-negative breast cancer. Cancer Res; 76(22); 6555-67. ©2016 AACR.
| S-EPMC5290198 | biostudies-literature
Project description:Pancreatic cancer remains a lethal disease with limited treatment options. At the time of diagnosis, approximately 80% of these patients present with unresectable tumors caused by either locally advanced lesions or progressive metastatic growth. Therefore, development of novel treatment strategies and new therapeutics is needed. Xanthohumol (XN) has emerged as a potential compound that inhibits various types of cancer, but the molecular mechanism underlying the effects of XN remains unclear. In the present study, we have assessed the efficacy of XN on pancreatic cancer cell lines (AsPC-1, PANC-1, L3.6pl, MiaPaCa-2, 512, and 651) against cell growth in real time and using colony-forming assays. Treatment with XN resulted in reduction in cellular proliferation in a dose- and time-dependent manner. The growth suppression effect of XN in pancreatic cancer cell lines is due to increased apoptosis via the inhibition of the Notch1 signaling pathway, as evidenced by reduction in Notch1, HES-1, and survivin both at mRNA as well as protein levels. Notch1 promoter reporter analysis after XN treatment indicated that XN downregulates Notch promoter activity. Importantly, overexpression of active Notch1 in XN-treated pancreatic cancer cells resulted in negation of growth suppression. Taken together, these findings demonstrate, for the first time, that the growth suppressive effect of XN in pancreatic cancer cells is mainly mediated by Notch1 reduction.
| S-EPMC4554525 | biostudies-literature
Project description:Although aberrant expression of miR-34a, an essential tumor suppressor miRNA, has been frequently observed in colon cancer (CCa), whether miR-34a can regulate CCa progression by modulating other facets of this malignancy (such as multidrug resistance, MDR) remains unknown. Here, we report for the first time that miR-34a expression was significantly downregulated in clinical CCa samples from oxaliplatin-resistant patients and in experimentally established multidrug-resistant CCa cells. By using histoculture drug response assay, we further confirmed that clinical CCa samples with lower miR-34a expression appeared to be more resistant to chemotherapy. Functionally, ectopic expression of exogenous miR-34a resensitized multidrug-resistant HCT-8/OR cells to oxaliplatin treatment, whereas miR-34a inhibition augmented the oxaliplatin resistance in chemosensitive HCT-8 cells. Mechanistically, miR-34a positively regulated the mRNA stability of the ornithine decarboxylase antizyme 2 (OAZ2) by directly targeting its three prime untranslated region (3'UTR). Consequently, suppression of the expression of miR-34a/OAZ2 signaling by chemotherapeutic agents significantly enhanced the activation of MDR-associated ATP-binding cassette (ABC) transporters and antiapoptosis pathways, thus leading to MDR development in CCa cells. Collectively, our combined analysis reveals a critical role of miR-34a/OAZ2 cascade in conferring a proper cellular response to CCa chemotherapy.
| S-EPMC6098920 | biostudies-literature
Project description:OBJECTIVES:Notch1 regulates tumor biology in a complex, context-dependent manner. The roles of Notch1 in tongue cancer are still controversial. The aim of this study is to investigate the roles of Notch1 in tongue cancer. MATERIALS AND METHODS:The expression of Notch1 was tested between tongue cancer and normal samples by using immunohistochemistry. Tongue cancer cells were transfected with siRNA or plasmid, respectively. Cell proliferation, apoptosis, migration and invasion ability were tested in appropriate ways. The subcutaneous tumor model was established to observe the tumor growth. RESULTS:Notch1 was upregulated in tongue carcinoma tissues and the expression of Notch1 was related with tumor stage and differentiation. Overexpression of Notch1 could increase tongue cancer cells proliferation, invasion and migration. But inhibited the expression of Notch1 could decrease cells proliferation, invasion and migration and promote cell apoptosis in vitro and in vivo. CONCLUSION:Our results prove that the oncogenic role of Notch1 in tongue cancer and provide the direction of targeted therapy of tongue cancer.
| S-EPMC5884382 | biostudies-literature
Project description:Evidence is accumulating for the role of cancer stem cells (CSCs) in mediating chemoresistance in patients with metastatic colorectal cancer (mCRC). A disintegrin and metalloproteinase domain 17 (ADAM17; also known as tumor necrosis factor-?-converting enzyme [TACE]) was shown to be overexpressed and to mediate cell proliferation and chemoresistance in CRC cells. However, its role in mediating the CSC phenotype in CRC has not been well-characterized. The objective of the present study was to determine whether ADAM17 regulates the CSC phenotype in CRC and to elucidate the downstream signaling mechanism that mediates cancer stemness. We treated established CRC cell lines and a newly established human CRC cell line HCP-1 with ADAM17-specific small interfering RNA (siRNA) or the synthetic peptide inhibitor TAPI-2. The effects of ADAM17 inhibition on the CSC phenotype and chemosensitivity to 5-fluorouracil (5-FU) in CRC cells were examined. siRNA knockdown and TAPI-2 decreased the protein levels of cleaved Notch1 (Notch1 intracellular domain) and HES-1 in CRC cells. A decrease in the CSC phenotype was determined by sphere formation and ALDEFLUOR assays. Moreover, TAPI-2 sensitized CRC cells to 5-FU by decreasing cell viability and the median lethal dose of 5-FU and increasing apoptosis. We also showed the cleavage and release of soluble Jagged-1 and -2 by ADAM17 in CRC cells. Our studies have elucidated a role of ADAM17 in regulating the CSC phenotype and chemoresistance in CRC cells. The use of drugs that inhibit ADAM17 activity might increase the therapeutic benefit to patients with mCRC and, potentially, those with other solid malignancies.
| S-EPMC4807666 | biostudies-literature
Project description:The breast cancer stem cells (BCSC) play important roles in breast cancer occurrence, recurrence and metastasis. However, the role of estrogen signaling, a signaling pathway important in development and progression of breast cancer, in regulation of BCSC has not been well established. Previously, we identified and cloned a variant of estrogen receptor α, ER-α36, with a molecular weight of 36 kDa. ER-α36 lacks both transactivation domains AF-1 and AF-2 of the 66 kDa full-length ER-α (ER-α66) and mediates rapid estrogen signaling to promote proliferation of breast cancer cells. In this study, we aim to investigate the function and the underlying mechanism of ER-α36-mediated rapid estrogen signaling in growth regulation of the ER-positive breast cancer stem/progenitor cells. ER-positive breast cancer cells MCF7 and T47D as well as the variants with different levels of ER-α36 expression were used. The effects of estrogen on BCSC's abilities of growth, self-renewal, differentiation and tumor-seeding were examined using tumorsphere formation, flow cytometry, indirect immunofluorence staining and in vivo xenograft assays. The underlying mechanisms were also studied with Western-blot analysis. We found that 17-β-estradiol (E2β) treatment increased the population of ER-positive breast cancer stem/progenitor cells while failed to do so in the cells with knocked-down levels of ER-α36 expression. Cells with forced expression of recombinant ER-α36, however, responded strongly to E2β treatment by increasing growth in vitro and tumor-seeding efficiency in vivo. The rapid estrogen signaling via the AKT/GSK3β pathway is involved in estrogen-stimulated growth of ER-positive breast cancer stem/progenitor cells. We concluded that ER-α36-mediated rapid estrogen signaling plays an important role in regulation and maintenance of ER-positive breast cancer stem/progenitor cells.
| S-EPMC3928099 | biostudies-literature
Project description:Liver cancer stem cells (LCSCs) initiate hepatocellular carcinoma (HCC) and contribute to its recurrence and treatment resistance. Studies have suggested ZBP-89 as a candidate tumor suppressor in HCC. We explored the role of ZBP-89 in the regulation of LCSCs. This study was performed in liver tissue samples from 104 HCC patients, 2 cell lines and mouse tumor models. We demonstrated that ZBP-89 was weakly expressed in LCSCs. Patients with high expression of LCSC markers displayed reduced survivals and higher recurrence rates after curative surgical operation. The expression of ZBP-89 was predictive for decreased recurrence. LCSC markers were negatively correlated with ZBP-89 in HCC tissues and in enriched liver tumor spheres. The exogenous expression of ZBP-89 attenuated the tumor-sphere formation and secondary colony formation capabilities of LCSCs in vitro and tumorigenicity in vivo. Furthermore, the negative effect of ZBP-89 on cancer stemness was Notch1-dependent. Localized with Notch1 intracellular domain (NICD1) in the nucleus, ZBP-89 repressed the Notch1 signaling pathway by competitive binding to NICD1 with MAML1. Collectively, ZBP-89 negatively regulates HCC stemness via inhibiting the Notch1 signaling.
| S-EPMC7226908 | biostudies-literature