RESUMO
The present study aims to investigate the roles of TCF4 and its underlying mechanism in colorectal cancer (CRC). Doxorubicin-resistant DLD-1 (DLD1 DR), TCF4 overexpression, and TCF4 knockdown cell lines were constructed. A flow cytometer was used to analyze frequencies of CD133+ cell in the DLD1 and DLD1 DR cells. Quantitative real-time PCR (qPCR) was used to determine the expressions of cancer stem cell (CSC) makers. Stemness of CRC cells were determined using tumorsphere formation assay. The correlation between TCF4 and ZEB1/ZEB2 were determined using public data from The Cancer Genome Atlas (TCGA) datasets. ZEB1/ZEB2 overexpression cell lines were constructed and cell viabilities were then determined using MTT and colony formation assays. TCF4 overexpression promoted proliferation of CRC cell lines and relative expressions of TCF4 were significantly increased in the DLD1 DR cells. TCF4 overexpression promoted CRC cell doxorubicin resistance, whereas TCF4 knockdown significantly decreased doxorubicin resistance. Additionally, TCF4 overexpression also significantly increased frequencies of CSC cells, expressions of CSC markers, and CRC ability to form tumorsphere. Furthermore, TCF4 promoted ZEB1 and ZEB2 expression, leading to CRC proliferation and doxorubicin resistance. TCF4 promoted CRC doxorubicin resistance and stemness by regulating expressions of ZEB1 and ZEB2.
Assuntos
Neoplasias Colorretais/metabolismo , Células-Tronco Neoplásicas/metabolismo , Fator de Transcrição 4/metabolismo , Homeobox 2 de Ligação a E-box com Dedos de Zinco/metabolismo , Homeobox 1 de Ligação a E-box em Dedo de Zinco/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/fisiologia , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Resistencia a Medicamentos Antineoplásicos , Humanos , Células-Tronco Neoplásicas/patologia , Fator de Transcrição 4/genética , Transfecção , Homeobox 2 de Ligação a E-box com Dedos de Zinco/biossíntese , Homeobox 2 de Ligação a E-box com Dedos de Zinco/genética , Homeobox 1 de Ligação a E-box em Dedo de Zinco/biossínteseRESUMO
AIM: To examine the expression status of long-noncoding RNA LINC00265 and mechanistically elucidate its involvements in colorectal cancer (CRC). METHODS: Relative abundances of LINC00265, miR-216b-5p, and tripartite-motif (TRIM)44 transcript were determined with real-time polymerase chain reaction. Cell viability was measured with cell counting kit-8 kit. Glucose uptake, pyruvate, and lactate production were quantified with commercially available kits. The potential regulatory effects of miR-216b-5p on both LINC00265 and TRIM44 were interrogated by luciferase reporter assay. The direct association between miR-216b-5p with both LINC00265 and TRIM44 was analyzed with pull-down assay. The TRIM44 protein was quantitated by western blotting. RESULTS: LINC00265 was upregulated in CRC both in vivo and in vitro, which intimately associated with poorer prognosis. LINC00265-deficiency resulted into decreases in cell viability, glucose uptake, pyruvate production, and lactate production. Mechanistically, LINC00265 directly bound to miR-216b-5p and negatively regulated miR-216b-5p. Consequently, the suppression on TRIM44 expression was released. Supplementation with ectopic miR-216b-5p significantly compromised the oncogenic activities of LINC00265 in CRC cells. CONCLUSION: Our study highlighted the contribution of LINC00265/miR-216b-5p/TRIM44 signaling axis in CRC.
Assuntos
Neoplasias Colorretais/genética , Glicólise/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Ácido Láctico/biossíntese , RNA Longo não Codificante/metabolismo , Proteínas com Motivo Tripartido/metabolismo , Linhagem Celular Tumoral , Sobrevivência Celular/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Reação em Cadeia da Polimerase em Tempo Real , Transdução de Sinais/genéticaRESUMO
BACKGROUND/AIMS: MicroRNAs (miRNAs) are a group of small RNA molecules that post-transcriptionally regulate gene expression. Aberrant expression of miRNAs has been associated with tumorigenesis in various cancers. miR-544a is an understudied miRNA that has recently been implicated in regulating invasion in lung cancer. However, its role in regulating invasion and the underlying mechanism have not been investigated in colorectal cancer (CRC) cells. METHODS: Microarray analysis was performed in metastatic colorectal tumor samples and their matched normal tissues to identify differentially expressed miRNAs. Quantitative real-time PCR was used to detect miR-544a levels in tumor samples and CRC cell lines with varying metastatic properties. miR-544a mimic or inhibitor was transfected into SW480 and HCT116 cells, respectively, followed by wound healing and invasion assays. Western Blot and luciferase assay were performed to investigate the direct target of miR-544a. Xenograft mouse models was used to examine in vivo function of miR-544a. RESULTS: Our data showed that expression of miR-544a was significantly up-regulated in metastatic tumor samples and CRC cell lines. Inhibition of miR-544a reduced migration and invasion in HCT116 cells. Homeobox A10 (HOXA10) was the direct target of miR-544a which was required for the function of miR-544a in regulating invasiveness. miR-544a inhibitor and/or HOXA10 overexpression reduced lung metastases in HCT116 xenografts. CONCLUSIONS: Our study demonstrates that miR-544a regulates invasive and metastatic properties of CRC cells by modulating HOXA10 expression level both in vitro and in vivo. miR-544a may represent a new therapeutic target for the intervention of metastatic colorectal cancer.
Assuntos
Carcinoma/genética , Neoplasias Colorretais/genética , Proteínas de Homeodomínio/genética , MicroRNAs/genética , Animais , Western Blotting , Células CACO-2 , Carcinoma/patologia , Carcinoma/secundário , Adesão Celular , Linhagem Celular Tumoral , Movimento Celular/genética , Neoplasias Colorretais/patologia , Feminino , Células HCT116 , Proteínas Homeobox A10 , Proteínas de Homeodomínio/metabolismo , Humanos , Immunoblotting , Imuno-Histoquímica , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/secundário , Camundongos , Camundongos Nus , Invasividade Neoplásica/genética , Metástase Neoplásica , Transplante de Neoplasias , Reação em Cadeia da Polimerase em Tempo Real , Regulação para CimaRESUMO
Oncogene and non-oncogene addictions describe the phenomenon that tumor cells become reliant on certain genes for maintenance of malignancy. Reversal of these mutations profoundly affects tumor growth and survival, providing a fundamental rationale for development of targeted cancer therapy. However, inadequate knowledge on cancer signaling networks and lack of potential drug targets limited its clinical application. A screen was conducted using a custom small interfering RNA (siRNA) library in colorectal cancer (CRC). Transient knockdown followed by cell proliferation assays were performed to validate the essentiality of PRKDC (Protein Kinase, DNA-Activated, Catalytic Polypeptide) in CRC. Western blot analysis was performed to examine the mechanism by which PRKDC confers selective survival advantage in CRC cells. Inducible knockdown and overexpression cell lines were introduced into nude mice to assess PRKDC dependency of CRC cells in vivo. PRKDC expression level in patient samples and overall survival of patients with low or high PRKDC expression were analyzed. Transient knockdown of PRKDC reduced cell proliferation/survival in HCT116 and DLD1, but not FHC cells. PRKDC down-regulation induced apoptosis partially through inhibiting AKT activation, and sensitized HCT116 cells to chemotherapeutic agents interfering with DNA replication. Inducible knockdown of PRKDC inhibited tumor growth in vivo. PRKDC was up-regulated in cancerous tissues compared with normal tissues. Patients with high PRKDC expression showed poorer overall survival. PRKDC is an essential gene required for CRC cell proliferation/survival, which may represent as a potential prognostic biomarker and an ideal therapeutic target for CRC.
