Project description:To study wither loss of CINP rescues global gene expression by KLF5 overexpression, we compare the effect of siRNA-mediated CINP silencing on K12 cells (TSU-PR1 cell line with stable KLF5 expression).
Project description:Transcriptional profiling of differential miRNA expression in mouse RAW264.7 preosteoclast cells comparing control untreated cells with RAW264.7 cells treated for 6 days. Treatment conditiones tested included 50ng/mL RANKL or indicated bone metastasis tumor cell conditioned media from 4T1, 4T1.2, TSU-PR1, and TSU-PR1-B2 cell lines.
Project description:Transcriptional profiling of differential miRNA expression in mouse RAW264.7 preosteoclast cells comparing control untreated cells with RAW264.7 cells treated for 6 days. Treatment conditiones tested included 50ng/mL RANKL or indicated bone metastasis tumor cell conditioned media from 4T1, 4T1.2, TSU-PR1, and TSU-PR1-B2 cell lines. Two-condition experiment, Control cells vs. treated cells.
Project description:Protein tyrosine phosphatase 1B (PTP1B) plays a key role in developing different types of cancer. However, the molecular mechanism underlying this effect is unclear. To identify possible molecular targets of PTP1B that mediate its positive role in tumorigenesis, we undertook a SILAC-based phosphoproteomic approach, which allowed us to identify the Cyclin-dependent kinase 3 (Cdk3) as a novel PTP1B substrate. Molecular docking studies revealed stable interactions between the PTP1B catalytic domain and Cdk3. In addition, we observed that PTP1B dephosphorylates Cdk3 at Tyrosine residue 15 in vitro and interacts with it in the nucleus and cytoplasm of human glioblastoma (GB) cells. Finally, we found that the pharmacological inhibition of PTP1B or its depletion with siRNA leads to cell cycle arrest with the diminished activity of Cdk3, the consequent hypophosphorylation of Rb, and the down-regulation of E2F and its target genes Cdk1, Cyclin A, and Cyclin E1. These data delineate a novel signaling pathway from PTP1B to Cdk3 required for efficient cell cycle progression in an Rb-E2F dependent manner in human GB cells and suggest new therapeutic strategies for treating these tumors.
Project description:Activation of the Ras/Erk pathway upregulates expression of the Kruppel-like Factor 5 (KLF5) transcription factor, and KLF5 is a downstream mediator of Ras oncogenic signaling. Specifically, in bladder and colon cancer cell lines KLF5 upregulates the Ras-pathway target gene cyclin D1, and facilitates entry into the S phase of the cell cycle. Ras mutations are common in lung cancer, but a role for KLF5 in lung tumorigenesis has not been defined. To this end, we manipulated KLF5 expression in four Ras-mutant human lung adenocarcinoma cell lines to find that KLF5 significantly modulates anchorage-independent growth, a mutant Ras phenotype. However, in a mouse model of human lung adenocarcinoma, K-RasG12D does not critically require Klf5 to mediate oncogenesis or induce cyclin D1 expression. Patients with lung tumors expressing high levels of KLF5 have significantly better prognosis than those with low or no KLF5 expression (opposite of mutant Ras prognosis). The latter may be explained by KLF5 transcriptional repression of the ATP-binding cassette, sub-family G (WHITE), member 2 (ABCG2), an anthracycline transporter. In agreement with this, KLF5 knockdown cells display significantly more Hoechst â??side populationâ?? and resistance to doxorubicin. In summary, while KLF5 is not an obligate partner in Ras oncogenic signaling, KLF5 control of ABCG2 expression is significant to patient survival. Experiment Overall Design: Total RNA was extracted from H441 cells transduced with KLF5-specific shRNA (KD), KLF5 over expression (OE) and MSCV empty vertor (NT) respectively. The cRNAs was then hybridized to Human Genome U133 Plus 2.0 Arrays (Affymetrix) according to manufacturerâ??s protocol.
Project description:To further examine the gene expression of isolated primary mouse proximal tubular epithelial cells (mPTECs) during ex vivo culture, we have employed whole genome microarray expression profiling as a discovery platform to identify genes with the potential to distinguish the key regulatory transcription factor which was significantly altered. Primary culuture of mPTECs were cultured on culture dishes for 1 and 3 days. As compared to freshly isolated mPTECs, a 1801-gene consensus signature was identified that distinguished between day 1 and and day 3 samples. Within these genes, 78 transcriptal factors were dramatically altered. Expression of three genes (KLF5, KLF4, and CCND1) from this signature was quantified in the same RNA samples by RT-PCR. The proliferation of mouse proximal tubular epithelial cells in ex vivo culture depends on matrix stiffness. Combined analysis of the microarray and experimental data revealed that Krüppel-like factor 5 (Klf5) was the most upregulated transcription factor accompanied by Krüppel-like factor 4 (Klf4) downregulation when cells on stiff matrix. These changes were reversed by soft matrix via ERK inactivation. Knockdown of Klf5 or forced-expression of Klf4 inhibited stiff matrix-induced cell spreading and proliferation, suggesting that Klf5/Klf4 act as positive/negative regulators, respectively. Moreover, stiff matrix-activated ERK increased the protein level and nuclear translocation of mechanosensitive Yes-associated protein 1 (YAP1), which is reported to prevent Klf5 degradation. Finally, in vivo model of unilateral ureteral obstruction (UUO) revealed that matrix stiffness-regulated Klf5/Klf4 is related to the pathogenesis of renal fibrosis. In the dilated tubules of obstructed kidney, ERK/YAP1/Klf5/Cyclin D1 axis were upregulated and Klf4 was downregulated. Inhibition of collagen crosslinking by lysyl oxidase inhibitor alleviated UUO-induced tubular dilatation and proliferation with preserving Klf4 and suppressing the ERK/YAP1/Klf5/Cyclin D1 axis. This study unravels a novel mechanism how matrix stiffness regulates cellular proliferation and highlights the importance of matrix stiffness-modulated Klf5/Klf4 in the regulation of renal physiological functions and fibrosis progression. Gene expression in cultured mPTECs was measured at 0, 1 and 3 days after culturing on culture dishes.
Project description:Activation of the Ras/Erk pathway upregulates expression of the Kruppel-like Factor 5 (KLF5) transcription factor, and KLF5 is a downstream mediator of Ras oncogenic signaling. Specifically, in bladder and colon cancer cell lines KLF5 upregulates the Ras-pathway target gene cyclin D1, and facilitates entry into the S phase of the cell cycle. Ras mutations are common in lung cancer, but a role for KLF5 in lung tumorigenesis has not been defined. To this end, we manipulated KLF5 expression in four Ras-mutant human lung adenocarcinoma cell lines to find that KLF5 significantly modulates anchorage-independent growth, a mutant Ras phenotype. However, in a mouse model of human lung adenocarcinoma, K-RasG12D does not critically require Klf5 to mediate oncogenesis or induce cyclin D1 expression. Patients with lung tumors expressing high levels of KLF5 have significantly better prognosis than those with low or no KLF5 expression (opposite of mutant Ras prognosis). The latter may be explained by KLF5 transcriptional repression of the ATP-binding cassette, sub-family G (WHITE), member 2 (ABCG2), an anthracycline transporter. In agreement with this, KLF5 knockdown cells display significantly more Hoechst “side population” and resistance to doxorubicin. In summary, while KLF5 is not an obligate partner in Ras oncogenic signaling, KLF5 control of ABCG2 expression is significant to patient survival.
Project description:High-risk B-cell acute lymphoblastic leukemia (B-ALL) remains a therapeutic challenge despite advances in the use of tyrosine kinase inhibitors and chimeric- antigen-receptor engineered T cells. Lymphoblastic-leukemia precursors are highly sensitive to oxidative stress. KLF5 is a member of the Krüppel-like family of transcription factors. KLF5 expression is repressed in B-ALL, including BCR-ABL1+ B-ALL. Here, we demonstrate that forced expression of KLF5 in B-ALL cells bypasses imatinib resistance not associated with mutations of BCR-ABL. Expression of Klf5 impaired leukemogenic activity of BCR-ABL1+ B-cell precursors in vitro and in vivo. The complete genetic loss of Klf5 reduced oxidative stress, increased regeneration of reduced glutathione and decreased apoptosis of leukemic precursors. Klf5 regulation of glutathione levels was mediated by its regulation of glutathione-S-transferase Mu 1 (Gstm1), an important regulator of glutathione-mediated detoxification and protein glutathionylation. Expression of Klf5 or the direct Klf5 target gene Gstm1 inhibited clonogenic activity of Klf5∆/∆ leukemic B-cell precursors and unveiled a Klf5-dependent regulatory loop on glutamine-dependent glutathione metabolism. In summary, we describe a novel mechanism of Klf5 B-ALL suppressor activity through its direct role on the metabolism of antioxidant glutathione levels, a crucial positive regulator of leukemic precursor survival.
Project description:Glycogen synthase kinase-3β (GSK-3β) has been recently identified as an important regulator of stem cell function. In vitro studies show that GSK-3β inhibition delays proliferation of human haematopoietic progenitor cells while increasing numbers of late dividing multipotent progenitors. Gene expression analysis revealed that GSK-3β inhibition modulates the expression of a subset of genes that are transcriptional targets for cytokines. GSK-3β inhibition antagonised down-regulation of genes encoding cyclin dependent kinase inhibitor p57 and a member of the growth arrest and DNA damage 45 family, GADD45B as well as up-regulation of cyclin D1 by cytokines, providing a possible mechanism for the BIO-induced delay in cell cycle progression. Surprisingly, inhibition of GSK-3β earlier shown to prevent β-catenin degradation and promote the nuclear accumulation of β-catenin was not sufficient to activate its transcriptional targets in haematopoietic stem cells. GSK-3β inhibition up-regulated the expression of a several positive regulators of stem cell function suppressed during cytokine-induced proliferation. The data supports a clinical role for GSK-3β inhibition to improve engraftment efficiency of ex vivo expanded stem cells. Total RNA was isolated from three groups following expansion of CD34+ cells in cytokikes and then treatment with BIO, as described below.
Project description:To further examine the gene expression of isolated primary mouse proximal tubular epithelial cells (mPTECs) during ex vivo culture, we have employed whole genome microarray expression profiling as a discovery platform to identify genes with the potential to distinguish the key regulatory transcription factor which was significantly altered. Primary culuture of mPTECs were cultured on culture dishes for 1 and 3 days. As compared to freshly isolated mPTECs, a 1801-gene consensus signature was identified that distinguished between day 1 and and day 3 samples. Within these genes, 78 transcriptal factors were dramatically altered. Expression of three genes (KLF5, KLF4, and CCND1) from this signature was quantified in the same RNA samples by RT-PCR. The proliferation of mouse proximal tubular epithelial cells in ex vivo culture depends on matrix stiffness. Combined analysis of the microarray and experimental data revealed that Krüppel-like factor 5 (Klf5) was the most upregulated transcription factor accompanied by Krüppel-like factor 4 (Klf4) downregulation when cells on stiff matrix. These changes were reversed by soft matrix via ERK inactivation. Knockdown of Klf5 or forced-expression of Klf4 inhibited stiff matrix-induced cell spreading and proliferation, suggesting that Klf5/Klf4 act as positive/negative regulators, respectively. Moreover, stiff matrix-activated ERK increased the protein level and nuclear translocation of mechanosensitive Yes-associated protein 1 (YAP1), which is reported to prevent Klf5 degradation. Finally, in vivo model of unilateral ureteral obstruction (UUO) revealed that matrix stiffness-regulated Klf5/Klf4 is related to the pathogenesis of renal fibrosis. In the dilated tubules of obstructed kidney, ERK/YAP1/Klf5/Cyclin D1 axis were upregulated and Klf4 was downregulated. Inhibition of collagen crosslinking by lysyl oxidase inhibitor alleviated UUO-induced tubular dilatation and proliferation with preserving Klf4 and suppressing the ERK/YAP1/Klf5/Cyclin D1 axis. This study unravels a novel mechanism how matrix stiffness regulates cellular proliferation and highlights the importance of matrix stiffness-modulated Klf5/Klf4 in the regulation of renal physiological functions and fibrosis progression.