Immature Colon Carcinoma Transcript-1 Research Articles

ICT1 Promotes Osteosarcoma Cell Proliferation and Inhibits Apoptosis via STAT3/BCL-2 Pathway.

Osteosarcoma (OS) is a familiar malignant bone tumor that occurs mainly in adolescents. Immature colon carcinoma transcript-1 (ICT1) is an important member of the large mitoribosomal subunit in mitochondrial ribosomes, which has been shown to be closely related to tumorigenesis. Its expression and function in OS, however, remained unclear. Here, we showed that ICT1 was significantly upregulated in OS and promoted the growth of OS cells. Mechanistically, ICT1 acted as an oncogene in OS and promoted proliferation and inhibited apoptosis of OS cells through the STAT3/BCL-2 axis. These results reveal a novel insight into the role of the ICT1/STAT3/BCL-2 axis in OS and therefore may represent a novel molecular target for novel treatments.

Knockdown of immature colon carcinoma transcript1 induces suppression of proliferation, S-phase arrest and apoptosis in leukemia cells.

Immature colon carcinoma transcript1 (ICT1), a human mitochondrial translation release factor, is a ribosome-dependent codon-independent peptidyl-tRNA hydrolase. ICT1-deficiency has been recognized as a cell growth inhibitor of hepatoblastoma and glioblastoma multiforme. To explore the role of ICT1 in human leukemia, 2short hairpin RNAs (shRNAs) targeting ICT1 sequences were designed in leukemia U937 cells. The successful infection of ICT1 in the U937 cells was observed under a fluorescence microscope and further quantified by western blotting and quantitative real-time PCR (qRT-PCR) analysis. Tetrazolium dye (MTT) assay revealed a significant decrease in proliferation of ICT1-knockdown U937 cells on the fourth and fifth day as compared with the control. Depletion of ICT1 resulted in an increase in Sphase and sub-G1 (representing cell apoptosis) fractions. AnnexinV-APC/7-AAD staining assay confirmed that knockdown of ICT1 played a crucial role in boosting early and late apoptotic programs in U937 cells. Downregulation of ICT1 also altered cyclinA2 transcription expression, caspase-3 activity and p21 protein expression. Additionally, decreased levels of heat shock protein27 (HSP27) phosphorylation at Ser78 was correlated with knockdown of ICT1 in U937 cells. Thus, we concluded that the regulatory role of ICT1 in leukemia may be used as a potential therapeutic target for the treatment of leukemia.

Immature colon carcinoma transcript-1 promotes cell growth of hepatocellular carcinoma via facilitating cell cycle progression and apoptosis resistance.

Immature colon carcinoma transcript-1 (ICT1) is a newly identified oncogene, which regulates proliferation, cell cycle progression and apoptosis of cancer cells. However, the clinical significance, biological function and underlying mechanisms of ICT1 in hepatocellular carcinoma (HCC) remain poorly known. In the present study, we showed that the expression of ICT1 in HCC tissues were notably overexpressed compared to corresponding non-tumor tissues. Accordingly, the relative levels of ICT1 were upregulated in HCC cell lines compared with LO2 cells. The positive expression of ICT1 was correlated with large tumor size and advanced TNM tumor stage. Kaplan-Meier plots indicated that ICT1-positive expression in HCC patients showed a prominent shorter survival. In addition, ICT1 knockdown inhibited proliferation and cell cycle progression, and induced apoptosis in HepG2 cells. While, ICT1 overexpression showed opposite effects on these cellular processes of Hep3B cells. Invivo experiments demonstrated that ICT1 deficiency reduced the growth of subcutaneous HCC in nude mice. Notably, ICT1 knockdown reduced the levels of CDK1, cyclinB1 and Bcl-2 and increased the expression of Bax in HepG2 cells. ICT1 overexpression resulted in upregulation of CDK1, cyclinB1 and Bcl-2, and downregulation of Bax in Hep3B cells. Furthermore, microRNA-134 (miR-134) was recognized as a direct upstream regulator and inversely modulated ICT1 abundance in HCC cells. Altogether, our data support that miR-134 regulation of ICT1 facilitates malignant phenotype of HCC cells probably via cell cycle and apoptosis-associated proteins including CDK1, cyclinB1, Bcl-2 and Bax.

MiR-205 regulation of ICT1 has an oncogenic potential via promoting the migration and invasion of gastric cancer cells

Immature colon carcinoma transcript-1 (ICT1) is a newly identified oncogene, which regulates mobility, apoptosis, cell cycle progression and proliferation of cancer cells. Nevertheless, the role of ICT1 and its clinical significance in gastric cancer (GC) is largely uncovered. Here, we found that ICT1 displayed higher expression in GC tissues compared to corresponding tumor-adjacent tissues. Further investigation confirmed ICT1 overexpression in GC cell lines. Clinical data disclosed that high ICT1 expression correlated with distant metastasis and advanced tumor-node-metastasis (TNM) stage. The Cancer Genome Atlas (TCGA) data further demonstrated that GC tissues with metastasis showed a significant higher level of ICT1 compared to those without metastasis. Furthermore, ICT1 overexpression notably predicted poor prognosis of GC patients. Functionally, we demonstrated that ICT1 knockdown suppressed invasion and migration of MGC-803 and BGC-823 cells in vitro. ICT1 overexpression promoted the mobility of SGC-7901 cells. Mechanistically, microRNA-205 (miR-205) was recognized as a direct down-regulator and inversely modulated ICT1 abundance in GC cells. miR-205 expression was down-regulated and negatively associated with ICT1 level in GC tissues. Underexpression of miR-205 indicated an obvious shorter survival of GC patients. miR-205 overexpression inhibited migration and invasion of MGC-803 cells, while these inhibitory effects were reversed by ICT1 restoration. Taken together, we have the earliest evidence that miR-205 regulation of ICT1 functions as an oncogene and prognostic biomarker in GC.

Immature colon carcinoma transcript-1 promotes proliferation of gastric cancer cells.

Gastric cancer is the fourth most common malignant tumor and has been considered as one of the leading causes of cancer-related death worldwide. The identification of the molecular mechanism during gastric cancer progression is urgently needed, which will help to develop more effective treatment strategies. As a component of the human mitoribosome, immature colon carcinoma transcript-1 (ICT1) might be involved in tumor formation and progression. However, its biological function and the corresponding mechanism in gastric cancer have been poorly characterized. To study the mechanism of ICT1 in gastric cancer, we first investigated the mRNA levels of ICT1 in human normal and gastric cancer tissues using datasets from the publicly available Oncomine database. The results showed that ICT1 is overexpressed in gastric cancer tissues. Then in order to study the role of ICT1 in gastric cancer, two shRNAs were used to silence ICT1 in MGC80-3 and AGS cells. Functional analysis showed ICT1 knockdown significantly inhibited the proliferation of gastric cancer cells and induced apoptosis. Further, mechanistic study demonstrated that ICT1 silencing induced cell-cycle arrest at G2/M phase via the suppression of cyclin A2 and cyclin B1. In addition, ICT1 silencing also increased cleaved caspase-3 and activated PARP in gastric cancer cells. These findings suggest that ICT1 may play a crucial role in promoting gastric cancer proliferation in vitro.

ICT1 predicts a poor survival and correlated with cell proliferation in diffuse large B-cell lymphoma

Immature colon carcinoma transcript-1 (ICT1) is a crucial member of the large mitoribosomal subunit in mitochondrial ribosome, which has been shown to be closely related to tumorigenesis. Its expression and function in human diffuse large B-cell lymphoma (DLBCL), however, remained elusive. In this study, analysis of public available Oncomine database suggested that the expression levels of ICT1 mRNA was significantly upregulated in DLBCL tissues. Consistently, we described ICT1 was remarkably upregulated in fresh DLBCL samples compared with the corresponding normal tissues using quantitative reverse-transcription polymerase chain reaction (qRT-PCR) and Western blotting. Moreover, ICT1 overexpression was associated with the poor overall survival (OS) of DLBCL patients. Finally, we used DLBCL cell lines to further probe the potential mechanisms, and found shRNA-mediated knockdown of ICT1 significantly suppressed DLBCL cell proliferation, induced cell cycle arrest at G0/G1 phase and apoptosis in vitro. Further verification showed that inhibition of ICT1 gene expression caused the upregulation of the p21, Bad and caspase-3, and downregulation of PCNA, Survivin, CDK4, CDK6 and Cyclin D1. Taken together, this study suggested that ICT1 may play an oncogenic role in human DLBCL by promoting cell proliferation and it might be a biomarker of unfavorable prognosis in DLBCL patients.

ICT1 knockdown inhibits breast cancer cell growth via induction of cell cycle arrest and apoptosis.

The protein encoded by immature colon carcinoma transcript1 (ICT1) is a component of the human mitochondrial ribosome, and is reported to be implicated in cell proliferation, viability and apoptosis of HeLa cells. This study was conducted to investigate the role of ICT1 in human breast cancer. Oncomine database was used to investigate ICT1 expression in human breast cancer tissues compared to normal tissues. The results showed that ICT1 was highly overexpressed in various human breast cancer subtypes. Then short hairpin RNA (shRNA)-mediated knockdown of ICT1 was performed in human breast cancer ZR-75-30 and T-47D cells. A series of functional analysis, including MTT, colony formation and flow cytometry assays were conducted after ICT1 knockdown. Our results demonstrated that knockdown of ICT1 significantly suppressed cell viability and proliferation through cell cycle arrest at the G2/Mphase and induced apoptosis in breast cancer cells. Furthermore, knockdown of ICT1 altered signaling pathways associated with cell growth and apoptosis, including phospho‑BAD (Ser112), phospho-PRAS40 (Thr246) and induction of phospho‑AMPKα (Thr172). Additionally, it was further confirmed by western blot analysis that ICT1 knockdown altered the expression of apoptosis- or cell cycle‑related proteins such as Bcl-2, caspase-3, CDK1, CDK2 and cyclinB. In conclusion, targeting ICT1 in breast cancer cells may provide a new strategy for breast cancer gene therapy.

Integrated analysis of different microarray studies to identify candidate genes in type 1 diabetes.

Type 1 diabetes (T1D), an autoimmune disease, occurs most commonly in children. Identifying altered gene expression in peripheral blood mononuclear cells (PBMCs) of T1D may lead to new strategies for preserving or improving β-ell function in patients with T1D. The Gene Expression Omnibus database was searched for microarray studies in PBMCs of T1D. Subsequently, gene expression datasets from multiple microarray studies were integrated to obtain differentially expressed genes (DEGs) between T1D and normal controls (NC). Gene function analysis was performed to determine the functions of the DEGs identified. Four microarray studies were available for analysis, including 199 T1D samples and 74 NC samples. Analysis revealed 695 genes that were significantly differentially expressed in PBMCs from T1D compared with NC samples, with 450 upregulated and 245 downregulated. Signal transduction (gene ontology [GO]: 0007165; false discovery rate [FDR] = 1.54 × 10-7 ) and protein binding (GO: 0005515; FDR = 2.93 × 10-24 ) were significantly enriched for the GO categories of biological processes and molecular functions, respectively. The most significant pathway in the Kyoto Encyclopedia of Genes and Genomes analysis was arachidonic acid metabolism (FDR = 1.44 × 10-3 ). Protein-protein interaction network analysis showed that the significant hub proteins contained immature colon carcinoma transcript1 (ICT1; degree = 214; clustering coefficient [C] = 4.39 × 10-5 ), zinc finger and BTB domain containing 16 (ZBTB16; degree = 112; C = 8.04 × 10-4 ), and SERTA domain containing 1 (SERTAD1; degree = 38; C = 0.0014). This integrated analysis will help develop improved therapies and interventions for T1D by identifying novel drug targets.

Immature Colon Carcinoma Transcript-1 (ICT1) Expression Correlates with Unfavorable Prognosis and Survival in Patients with Colorectal Cancer.

Colorectal cancer (CRC) is the third leading cause of death from cancer worldwide. Immature colon carcinoma transcript-1 (ICT1) has been reported to be correlated with lung cancer; however, whether ICT1 is a functional gene in CRC, as well as the molecular mechanism underlying ICT1 mediation of colorectal-tumor formation, remains unknown. The expression of ICT1 was firstly determined by using immunohistochemistry in 861 CRC specimens. The correlation of ICT1 expression with clinicopathological parameters and the survival rate was analyzed. Furthermore, we investigated the effect of ICT1 silencing on CRC cell proliferation and migration by MTT, colony formation, flow cytometry, and transwell in vitro. ICT1 is highly expressed in a cohort of human CRCs, and that higher ICT1 expression may lead to reduced overall survival rate of CRC. Likewise, ICT1 silencing lowered the cell viability through cell-cycle arrest, inhibited cell migration, and induced apoptosis in CRC. We further revealed a novel mechanism in which ICT1 promoted CRC growth via the intracellular AMPK, SAPK/JNK, and PARP signaling pathways. Our data showed that ICT1 could be an important target for CRC diagnosis and treatment.

Abstract 2292: The role of immature colon carcinoma transcript 1 during c-myc deregulation in fast-onset mouse plasmacytoma

Abstract Murine plasmacytoma (mPCT) models human blood cancers that involve the deregulation of c-myc by a translocation that juxtaposes c-myc to one of the immunoglobin loci. The fast-developing mPCT does not depend on c-myc translocation; rather infection with v-abl/c-myc retrovirus produces elevated c-myc levels. Chromosome 11 subcytoband E2 is always (100%) found duplicated compared to slow-developing mPCT (7.1%). The gene, immature colon carcinoma transcript1 (ict1) is located within 11E2 and overexpressed as a result of 11E2 duplication. The effect of ict1 overexpression during c-myc deregulation may contribute to the aggressive development of mPCT. Here we look at the tumorigenic potential of ict1 in vitro. The ict1 gene has been cloned into an Ecdysone inducible vector and transiently transfected (Nucleofection) into mouse PreB cells that also have inducible c-myc expression activated by 4-hydroxytamoxifen. This allows us to look at overexpression of ict1 along with c-myc simultaneously or each separately. Immunofluorescence was used to confirm overexpression of the target genes. Proliferation and apoptosis levels were determined for each condition by Edu and TUNEL assay respectively. Metaphase spreads were prepared before and after each experiment. We have confirmed by immunofluorescence overexpression of ict1 using the inducible vector system. A study in these cell lines shows that ict1 overexpression increases cell proliferation levels, and may reduce apoptosis compared to cells that were not induced for ict1/c-myc expression. Metaphase spreads show normal diploid chromosome number of 40 (at time 0, and every 24 hours). Further genetic analysis to identify any chromosomal abnormalities that may account for these changes will be performed (SKY). We have identified a potential role of ict1 overexpression in vitro. In order to further explore these results we will try to restore proliferation and apoptotic levels relative to a normal PreB cell phenotype in plasmacytoma cells in vitro in the MOPC 460D cell line, and ex vivo in plasmacytoma cells isolated from PCT-carrying mice. 11E2 is syntenic to human chromosome 17q25, which has chromosomal abnormalities in many other neoplasms, such as acute and chronic myeloid leukemia, neuroblastoma, breast, ovarian, thyroid cancers. If we can identify the role of overexpression of ict1 during c-myc deregulation in fast-onset mPCT, we can gain insight into the aggressiveness of the disease progression and determine if ict1 could lead to a new therapeutic target for aggressive blood cancers with c-myc deregulation. Citation Format: Amy K. Dahl, Ruedee Sakulratchata, Sabine Mai. The role of immature colon carcinoma transcript 1 during c-myc deregulation in fast-onset mouse plasmacytoma. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2292. doi:10.1158/1538-7445.AM2015-2292

Immature Colon Carcinoma Transcript 1 Is Essential for Prostate Cancer Cell Viability and Proliferation.

Prostate cancer is the second leading cause of cancer-related death among men in the United States. More recently, immature colon carcinoma transcript 1 (ICT1) has been reported to be overexpressed in various kinds of cancer cells. However, the role of ICT1 in human prostate cancer has not yet been determined. The authors selected two ICT1-specific short hairpin RNA (shRNA) sequences to block its endogenous expression in human androgen-independent prostate cancer cell lines DU145 and PC-3. Decreased ICT1 expression by either specific shRNA significantly inhibited cell viability and proliferation. Moreover, compared to controls, ICT1-silenced cells were more inclined to redistribute in the G2/M phase, leading to cell cycle arrest. Flow cytometry and Annexin V-APC/7-AAD double staining confirmed that knockdown of ICT1 increased late apoptotic cells. Furthermore, they found that ICT1 knockdown restricting G2-M transition may be partly through suppression of CDK1 and Cyclin B1. Knockdown of ICT1 induced apoptosis through activation of poly ADP-ribose polymerase and caspase 3, upregulation of Bax expression, and downregulation of Bcl-2 expression in DU145 cells. In conclusion, this study highlights the crucial role of ICT1 in promoting prostate cancer cell proliferation in vitro. The depletion of ICT1 by lentivirus-mediated shRNA or small molecular inhibitor may provide a novel therapeutic approach for the treatment of prostate cancer.

Knockdown of immature colon carcinoma transcript-1 inhibits proliferation of glioblastoma multiforme cells through Gap 2/mitotic phase arrest.

“Glioblastoma multiforme” (GBM) is the frequent form of malignant glioma. Immature colon carcinoma transcript-1 (ICT1) is essential for cell vitality and mitochondrial function and has been recognized in several human cancers. In the study reported here, we attempted to evaluate the functional role of ICT1 in GBM cells. Lentivirus-mediated RNA interference (RNAi) was applied to silence ICT1 expression in human GBM cell lines U251 and U87. Cell proliferation was measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony-formation assays. Cell-cycle progression was determined by flow cytometry with propidium iodide staining. The results revealed that lentivirus-mediated short hairpin RNA (shRNA) can specifically suppress the expression of ICT1 in U251 and U87 cells. Functional investigations proved for the first time, as far as we are aware, that ICT1 knockdown significantly inhibited the proliferation of both cell lines. Moreover, the cell cycle of U251 cells was arrested at Gap 2 (G2)/mitotic (M) phase after ICT1 knockdown, with a concomitant accumulation of cells in the Sub-Gap 1 (G1) phase. This study highlights the crucial role of ICT1 in promoting GBM cell proliferation, and provides a foundation for further study into the clinical potential of lentivirus-mediated silencing of ICT1 for GBM therapy.

A functional peptidyl-tRNA hydrolase, ICT1, has been recruited into the human mitochondrial ribosome.

Bioinformatic analysis classifies the human protein encoded by immature colon carcinoma transcript-1 (ICT1) as one of a family of four putative mitochondrial translation release factors. However, this has not been supported by any experimental evidence. As only a single member of this family, mtRF1a, is required to terminate the synthesis of all 13 mitochondrially encoded polypeptides, the true physiological function of ICT1 was unclear. Here, we report that ICT1 is an essential mitochondrial protein, but unlike the other family members that are matrix-soluble, ICT1 has become an integral component of the human mitoribosome. Release-factor assays show that although ICT1 has retained its ribosome-dependent PTH activity, this is codon-independent; consistent with its loss of both domains that promote codon recognition in class-I release factors. Mutation of the GGQ domain common to ribosome-dependent PTHs causes a loss of activity in vitro and, crucially, a loss of cell viability, in vivo. We suggest that ICT1 may be essential for hydrolysis of prematurely terminated peptidyl-tRNA moieties in stalled mitoribosomes.