Project description:Beckwith-Wiedemann syndrome (BWS) is a human stem cell disorder, and individuals with this disease have a substantially increased risk (~800-fold) of developing tumors. Epigenetic silencing of ?2-spectrin (?2SP, encoded by SPTBN1), a SMAD adaptor for TGF-? signaling, is causally associated with BWS; however, a role of TGF-? deficiency in BWS-associated neoplastic transformation is unexplored. Here, we have reported that double-heterozygous Sptbn1+/- Smad3+/- mice, which have defective TGF-? signaling, develop multiple tumors that are phenotypically similar to those of BWS patients. Moreover, tumorigenesis-associated genes IGF2 and telomerase reverse transcriptase (TERT) were overexpressed in fibroblasts from BWS patients and TGF-?-defective mice. We further determined that chromatin insulator CCCTC-binding factor (CTCF) is TGF-? inducible and facilitates TGF-?-mediated repression of TERT transcription via interactions with ?2SP and SMAD3. This regulation was abrogated in TGF-?-defective mice and BWS, resulting in TERT overexpression. Imprinting of the IGF2/H19 locus and the CDKN1C/KCNQ1 locus on chromosome 11p15.5 is mediated by CTCF, and this regulation is lost in BWS, leading to aberrant overexpression of growth-promoting genes. Therefore, we propose that loss of CTCF-dependent imprinting of tumor-promoting genes, such as IGF2 and TERT, results from a defective TGF-? pathway and is responsible at least in part for BWS-associated tumorigenesis as well as sporadic human cancers that are frequently associated with SPTBN1 and SMAD3 mutations.
Project description:Background:Renal fibrosis is a frequent pathway leading to end-stage kidney dysfunction. In addition, renal fibrosis is the ultimate manifestation of chronic kidney diseases (CKD). Long noncoding RNAs (lncRNAs) are known to be involved in occurrence of renal fibrosis, and lncRNA plasmacytoma variant translocation 1 (PVT1) has been reported to act as a key biomarker in renal diseases. However, the role of PVT1 in renal fibrosis remains unclear. Materials and Methods:HK-2 cells were treated with TGF-?1 to mimic renal fibrosis in vitro. Gene and protein expressions in HK-2 cells were measured by qRT-PCR and Western-blot, respectively. ELISA was used to test the level of creatinine (CR) and blood urea nitrogen (BUN) in serum of mice. Additionally, unilateral ureteral obstruction (UUO)-induced renal fibrosis mice model was established to investigate the effect of PVT1 on renal fibrosis in vivo. Results:PVT1 was upregulated in TGF-?1-treated HK-2 cells. In addition, TGF-?1-induced upregulation of ?-SMA and fibronectin in HK-2 cells was significantly reversed by PVT1 knockdown. Meanwhile, PVT1 bound to miR-181a-5p in HK-2 cells. Moreover, miR-181a-5p directly targeted TGF-?R1. Furthermore, miR-181a-5p antagonist could significantly reverse the anti-fibrotic effect of PVT1 knockdown. Besides, knockdown of PVT1 notably attenuated the symptom of renal fibrosis in vivo. Conclusion:Knockdown of PVT1 significantly inhibited the progression of renal fibrosis in vitro and in vivo. Thus, PVT1 may serve as a potential target for the treatment of renal fibrosis.
Project description:CHI3L1 (YKL40) is a secreted glycoprotein and elevated serum CHI3L1 level has been proved to be associated with poor prognosis in many human cancers. However, the mechanism of how CHI3L1 causes poor prognosis in cancers is still unknown. Here, considering that CHI3L1 is a liver specific/enriched protein, we use hepatocellular carcinoma as a model to study the function of CHI3L1. We showed that, both in vivo and in vitro, overexpression of CHI3L1 could promote liver cancer cells growth, migration and invasion. We then used RNA-seq to analyze the expression profiles of CHI3L1 overexpressed in two HCC cell lines and found that CHI3L1 overexpression affected genes that were involved in cell-cell adhesion, extracellular exosome and adherens junction. Western blot analysis further revealed that CHI3L1 could activate TGF-? signal pathways. Our data added new understanding of the mechanism of CHI3L1's action. 1) CHI3L1 promoted cancer cell proliferation by regulating cell cycles; 2) CHI3L1 promoted cancer cell invasion and metastasis; 3) CHI3L1 regulate liver cancer potentially by regulating the TGF-? signaling pathways; 4) CHI3L1 has direct kinase activities or activate kinase to phosphorylate SMAD2, SMAD3.
Project description:Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies and the therapeutic outcomes remain undesirable. Increasing evidence shows that aryl hydrocarbon receptor nuclear translocator like 2 (ARNTL2) plays crucial roles in tumorigenesis of multiple tumors. However, the expression status and functions of ARNTL2 in PDAC remain elusive. Here we showed that ARNTL2 expression was markedly upregulated in PDAC tissues and cell lines. elevated expression of ARNTL2 was positively related to unfavorable prognosis. Knockdown of ARNTL2 could suppress motility and invasive ability of PDAC cells in vitro, as well as tumor development in vivo. In addition, microRNA-26a-5p (miR-26a-5p) was identified as the crucial specific arbitrator for ARNTL2 expression and the expression of miR-26a-5p was inversely correlated with ARNTL2 expression in PDAC tissues. Functionally, elevated expression of miR-26a-5p was found to inhibit the proliferation, migration, and invasion of PDAC cells in vitro, while ARNTL2 increased expression could partially abolish the suppressive effect of miR-26a-5p. Mechanism study indicated that elevated expression of miR-26a-5p suppressed TGF/BETA signaling pathway by targeting ARNTL2 in PDAC cells. In conclusion, our data suggested that ARNTL2 acted as an oncogene to regulate PDAC growth. MiR-26a-5p/ARNTL2 axis may be a novel therapeutic candidate target in PDAC treatment.
Project description:Pancreatic ductal adenocarcinoma (PDA) remains a lethal human malignancy with historically limited success in treatment. The role of aberrant Notch signaling, which requires the constitutive activation of ?-secretase, in the initiation and progression of PDA is well defined and inhibitors of this pathway are currently in clinical trials. Here we investigated the in vivo therapeutic effect of PF-03084014, a selective ?-secretase inhibitor, alone and in combination with gemcitabine in pancreatic cancer xenografts. PF-03084014 treatment inhibited the cleavage of nuclear Notch 1 intracellular domain and Notch targets Hes-1 and Hey-1. Gemcitabine treatment showed good response but not capable of inducing tumor regressions and targeting the tumor-resident cancer stem cells (CD24(+)CD44(+) and ALDH(+) tumor cells). A combination of PF-03084014 and gemcitabine treatment resulted tumor regression in 3 of 4 subcutaneously implanted xenograft models. PF-03084014, and in combination with gemcitabine reduced putative cancer stem cells, indicating that PF-03084014 target the especially dangerous and resilient cancer stem cells within pancreatic tumors. Tumor re-growth curves plotted after drug treatments demonstrated that the effect of the combination therapy was sustainable than that of gemcitabine. Notably, in a highly aggressive orthotopic model, PF-03084014 and gemcitabine combination was effective in inducing apoptosis, inhibition of tumor cell proliferation and angiogenesis, resulting in the attenuation of primary tumor growth as well as controlling metastatic dissemination, compared to gemcitabine treatment. In summary, our preclinical data suggest that PF-03084014 has greater anti-tumor activity in combination with gemcitabine in PDA and provides rationale for further investigation of this combination in PDA.
Project description:The TGF-beta signaling pathway has a complex role in regulating mammary carcinogenesis. Here we demonstrate that the type III TGF-beta receptor (TbetaRIII, or betaglycan), a ubiquitously expressed TGF-beta coreceptor, regulated breast cancer progression and metastasis. Most human breast cancers lost TbetaRIII expression, with loss of heterozygosity of the TGFBR3 gene locus correlating with decreased TbetaRIII expression. TbetaRIII expression decreased during breast cancer progression, and low TbetaRIII levels predicted decreased recurrence-free survival in breast cancer patients. Restoring TbetaRIII expression in breast cancer cells dramatically inhibited tumor invasiveness in vitro and tumor invasion, angiogenesis, and metastasis in vivo. TbetaRIII appeared to inhibit tumor invasion by undergoing ectodomain shedding and producing soluble TbetaRIII, which binds and sequesters TGF-beta to decrease TGF-beta signaling and reduce breast cancer cell invasion and tumor-induced angiogenesis. Our results indicate that loss of TbetaRIII through allelic imbalance is a frequent genetic event during human breast cancer development that increases metastatic potential.
Project description:Breast cancer progression and metastasis have been linked to abnormal signaling by transforming growth factor-? (TGF-?) cytokines. In early-stage breast cancers, TGF-? exhibits tumor suppressor activity by repressing cell proliferation and inducing cell death, whereas in advanced-stage tumors, TGF-? promotes invasion and metastatic dissemination. The molecular mechanisms underlying pro-oncogenic activities of TGF-? are not fully understood. The present study validates the role of TGF-? signaling in cancer progression and explores mediators of pro-oncogenic TGF-? activities using the LM3 mammary adenocarcinoma cell line, derived from a spontaneous murine mammary adenocarcinoma. Expression of kinase-inactive TGF-? receptors decreased both basal and TGF-?-induced invasion. Analysis of signal transduction mediators showed that p38MAPK and MEK contribute to TGF-? stimulation of cell motility and invasion. TGF-? disrupted the epithelial actin structures supporting cell-cell adhesions, and increased linear actin filaments. Moreover, MEK and p38MAPK pathways showed opposite effects on actin remodeling in response to TGF-?. Blockade of Raf-MEK signaling enhanced TGF-? induction of actin stress-fibers whereas p38MAPK inhibitors blocked this effect. A novel observation was made that TGF-? rapidly activates the actin nucleation Arp2/3 complex. In addition, TGF-? stimulated matrix metalloproteinase MMP-9 secretion via a MAPK-independent pathway. Experiments using syngeneic mice showed that kinase-inactive TGF-? receptors inhibit the first stages of LM3 tumor growth in vivo. Our studies demonstrate that autocrine TGF-? signaling contributes to the invasive behavior of mammary carcinoma cells. Moreover, we show that both MAPK-dependent and -independent pathways are necessary for TGF-?-induced effects. Therefore, MEK-ERK and p38 MAPK pathways are potential venues for therapeutic intervention in pro-oncogenic TGF-? signaling.