Elevated OCT1 participates in colon tumorigenesis and independently predicts poor prognoses of colorectal cancer patients

CIP/KIP and INK4 families as hostages of oncogenic signaling

CIP/KIP and INK4 families of Cyclin-dependent kinase inhibitors (CKIs) are well-established cell cycle regulatory proteins whose canonical function is binding to Cyclin-CDK complexes and altering their function. Initial experiments showed that these proteins negatively regulate cell cycle progression and thus are tumor suppressors in the context of molecular oncology. However, expanded research into the functions of these proteins showed that most of them have non-canonical functions, both cell cycle-dependent and independent, and can even act as tumor enhancers depending on their posttranslational modifications, subcellular localization, and cell state context. This review aims to provide an overview of canonical as well as non-canonical functions of CIP/KIP and INK4 families of CKIs, discuss the potential avenues to promote their tumor suppressor functions instead of tumor enhancing ones, and how they could be utilized to design improved treatment regimens for cancer patients.

OCT1 regulates the migration of colorectal cancer cells by acting on LDHA

Colorectal cancer is one of the most common cancers with high morbidity and mortality. Effective treatments to improve the prognosis are still lacking. The results of online analysis tools showed that OCT1 and LDHA were highly expressed in colorectal cancer, and the high expression of OCT1 was associated with poor prognosis. Immunofluorescence demonstrated that OCT1 and LDHA co-localized in colorectal cancer cells. In colorectal cancer cells, OCT1 and LDHA were upregulated by OCT1 overexpression, but downregulated by OCT1 knockdown. OCT1 overexpression promoted cell migration. OCT1 or LDHA knockdown inhibited the migration, and the downregulation of LDHA restored the promoting effect of OCT1 overexpression. OCT1 upregulation increased the levels of HK2, GLUT1 and LDHA proteins in colorectal cancer cells. Consequently, OCT1 promoted the migration of colorectal cancer cells by upregulating LDHA.

The Regulation and Immune Signature of Retrotransposons in Cancer

Advances in sequencing technologies and the bioinformatic analysis of big data facilitate the study of jumping genes' activity in the human genome in cancer from a broad perspective. Retrotransposons, which move from one genomic site to another by a copy-and-paste mechanism, are regulated by various molecular pathways that may be disrupted during tumorigenesis. Active retrotransposons can stimulate type I IFN responses. Although accumulated evidence suggests that retrotransposons can induce inflammation, the research investigating the exact mechanism of triggering these responses is ongoing. Understanding these mechanisms could improve the therapeutic management of cancer through the use of retrotransposon-induced inflammation as a tool to instigate immune responses to tumors.

Suppression of OCT-1 in Metastatic Breast Cancer Cells Reduces Tumor Metastatic Potential, Hypoxia Resistance, and Drug Resistance

OCT-1/POU2F1 is a ubiquitously expressed transcription factor. Its expression starts at the earliest stage of embryonic development. OCT-1 controls genes involved in the regulation of differentiation, proliferation, cell metabolism, and aging. High levels of OCT-1 transcription factor in tumor cells correlate with tumor malignancy and resistance to antitumor therapy. Here, we report that suppression of OCT-1 in breast cancer cells reduces their metastatic potential and drug resistance. OCT-1 knockdown in the MDA-MB231 breast cancer cells leads to a fivefold decrease (p < 0.01) in cell migration rates in the Boyden chamber. A decrease in the transcription levels of human invasion signature (HIS) genes (ARHGDIB, CAPZA2, PHACTR2, CDC42, XRCC5, and CAV1) has been also demonstrated by real-time PCR, with high expression of these genes being a hallmark of actively metastasizing breast cancer cells. Transcriptional activity of ATF6 response elements is significantly reduced in the cell lines with decreased OCT-1 expression, which results in lower levels of adaptive EPR stress response. OCT-1 knockdown more than two times increases the MDA-MB231 cell death rate in hypoxia and significantly increases the doxorubicin or docetaxel-treated MDA-MB231 cell death rate. Our findings indicate that OCT-1 may be an important therapeutic target and its selective inhibition may have significant therapeutic effects and may improve prognosis in breast cancer patients.

TLR4 regulatory region variants reduce the susceptibility of small-cell lung cancer in Chinese population

OBJECTIVES

Toll-like receptors (TLRs) participate in the induction and regulation of immune responses and are closely related to the occurrence and development of small-cell lung cancer (SCLC). This study aimed to investigate the impact of polymorphisms in the regulatory regions of TLRs on the susceptibility of SCLC.

METHODS

The case-control study included 304 SCLC patients and 304 healthy controls. TLRs gene polymorphisms were genotyped by PCR-restrictive fragment length polymorphism analysis and TaqMan assay. Unconditional logistic regression was used to estimate odds ratio (OR) and its 95% confidence interval (95% CI).

RESULTS

Our results showed that TLR4 rs1927914 GG genotype and TLR4 rs7869402 TT genotype reduced the risk of SCLC with OR (95% CI) of 0.54 (0.32-0.90) and 0.47 (0.28-0.80), respectively. Stratified analysis suggested that TLR4 rs1927914 GG genotypes significantly reduced the risk of SCLC among male (OR = 0.35; 95% CI, 0.18-0.69; P < 0.01), the younger patients (OR = 0.49; 95% CI, 0.26-0.94; P = 0.03) and non-drinkers (OR = 0.47; 95% CI, 0.24-0.89; P = 0.02). TLR4 rs7869402 CT or TT genotype significantly reduced the susceptibility to SCLC among male patients (OR = 0.37; 95% CI, 0.19-0.71, P < 0.01), the younger patients (OR = 0.41; 95% CI, 0.22-0.79; P < 0.01), smokers (OR = 0.25; 95% CI, 0.10-0.60; P < 0.01) and drinkers (OR = 0.31; 95% CI, 0.11-0.88; P = 0.03). TLR3 rs5743303, TLR4 rs11536891, TLR5 rs1640816 and TLR7 rs3853839 had no significant correlation with the risk of SCLC.

CONCLUSIONS

These findings emphasized the important role of TLR4 in the development of SCLC.

OCT1 Is a Poor Prognostic Factor for Breast Cancer Patients and Promotes Cell Proliferation via Inducing NCAPH

Octamer transcription factor 1 (OCT1) is a transcriptional factor reported to be a poor prognostic factor in various cancers. However, the clinical value of OCT1 in breast cancer is not fully understood. In the present study, an immunohistochemical study of OCT1 protein was performed using estrogen receptor (ER)-positive breast cancer tissues from 108 patients. Positive OCT1 immunoreactivity (IR) was associated with the shorter disease-free survival (DFS) of patients (p = 0.019). Knockdown of OCT1 inhibited cell proliferation in MCF-7 breast cancer cells as well as its derivative long-term estrogen-deprived (LTED) cells. On the other hand, the overexpression of OCT1 promoted cell proliferation in MCF-7 cells. Using microarray analysis, we identified the non-structural maintenance of chromosomes condensin I complex subunit H (NCAPH) as a novel OCT1-taget gene in MCF-7 cells. Immunohistochemical analysis showed that NCAPH IR was significantly positively associated with OCT1 IR (p < 0.001) and that positive NCAPH IR was significantly related to the poor DFS rate of patients (p = 0.041). The knockdown of NCAPH inhibited cell proliferation in MCF-7 and LTED cells. These results demonstrate that OCT1 and its target gene NCAPH are poor prognostic factors and potential therapeutic targets for patients with ER-positive breast cancer.

Investigation of the Genome-Wide Genetic and Epigenetic Networks for Drug Discovery Based on Systems Biology Approaches in Colorectal Cancer

Colorectal cancer (CRC) is the third most commonly diagnosed type of cancer worldwide. The mechanisms leading to the progression of CRC are involved in both genetic and epigenetic regulations. In this study, we applied systems biology methods to identify potential biomarkers and conduct drug discovery in a computational approach. Using big database mining, we constructed a candidate protein-protein interaction network and a candidate gene regulatory network, combining them into a genome-wide genetic and epigenetic network (GWGEN). With the assistance of system identification and model selection approaches, we obtain real GWGENs for early-stage, mid-stage, and late-stage CRC. Subsequently, we extracted core GWGENs for each stage of CRC from their real GWGENs through a principal network projection method, and projected them to the Kyoto Encyclopedia of Genes and Genomes pathways for further analysis. Finally, we compared these core pathways resulting in different molecular mechanisms in each stage of CRC and identified carcinogenic biomarkers for the design of multiple-molecule drugs to prevent the progression of CRC. Based on the identified gene expression signatures, we suggested potential compounds combined with known CRC drugs to prevent the progression of CRC with querying Connectivity Map (CMap).

Short article: Influence of regulatory NLRC5 variants on colorectal cancer survival and 5-fluorouracil-based chemotherapy

BACKGROUND

NLRC5 is an interferon γ-inducible protein, which plays a role in immune surveillance with a potential influence on cancer survival.

OBJECTIVE

We aimed to evaluate the effect of potential regulatory variants in NLRC5 on overall survival and survival after 5-fluorouracil (5-FU)-based therapy of colorectal cancer (CRC) patients.

PATIENTS AND METHODS

We carried out a case-only study in a Czech population of 589 cases; 232 received 5-FU-based therapy. Eleven variants within NLRC5 were selected using in-silico tools. Associations between polymorphisms and survival were assessed by Cox regression analysis adjusting for age at diagnosis, sex, and TNM stage. Survival curves were derived using the Kaplan-Meier method.

RESULTS

Two variants showed a significant association with survival. All patients and metastasis-free patients at the time of diagnosis (pM0) who were homozygous carriers of the minor allele of rs27194 had a decreased overall survival (OSall and OSpM0) and event-free survival (EFSpM0) under a recessive model (OSall P=0.003, OSpM0 P=0.005, EFSpM0 P=0.01, respectively). OS was also decreased for all patients and for pM0 patients who carried at least one minor allele of rs289747 (OSall P=0.03 and OSpM0 P=0.003, respectively). Among CRC patients, who underwent a 5-FU-based adjuvant regimen, rs12445252 was associated with OSall, OSpM0 and EFSpM0, according to the dosage of the minor allele T (OSall P=0.0004, OSpM0 P=0.0001, EFSpM0 P=0.008, respectively).

CONCLUSION

Our results showed that polymorphisms in NLRC5 may be used as prognostic markers of survival of CRC patients, as well as for survival in response to 5-FU treatment.

Metformin Targets Mitochondrial Glycerophosphate Dehydrogenase to Control Rate of Oxidative Phosphorylation and Growth of Thyroid Cancer In Vitro and In Vivo

Purpose: Mitochondrial glycerophosphate dehydrogenase (MGPDH) is the key enzyme connecting oxidative phosphorylation (OXPHOS) and glycolysis as well as a target of the antidiabetic drug metformin in the liver. There are no data on the expression and role of MGPDH as a metformin target in cancer. In this study, we evaluated MGPDH as a potential target of metformin in thyroid cancer and investigated its contribution in thyroid cancer metabolism.Experimental Design: We analyzed MGPDH expression in 253 thyroid cancer and normal tissues by immunostaining and examined its expression and localization in thyroid cancer-derived cell lines (FTC133, BCPAP) by confocal microscopy. The effects of metformin on MGPDH expression were determined by qRT-PCR and Western blot analysis. Seahorse analyzer was utilized to assess the effects of metformin on OXPHOS and glycolysis in thyroid cancer cells. We analyzed the effects of metformin on tumor growth and MGPDH expression in metastatic thyroid cancer mouse models.Results: We show for the first time that MGPDH is overexpressed in thyroid cancer compared with normal thyroid. We demonstrate that MGPDH regulates human thyroid cancer cell growth and OXPHOS rate in vitro Metformin treatment is associated with downregulation of MGPDH expression and inhibition of OXPHOS in thyroid cancer in vitro Cells characterized by high MGPDH expression are more sensitive to OXPHOS-inhibitory effects of metformin in vitro and growth-inhibitory effects of metformin in vitro and in vivoConclusions: Our study established MGPDH as a novel regulator of thyroid cancer growth and metabolism that can be effectively targeted by metformin. Clin Cancer Res; 24(16); 4030-43. ©2018 AACR.

Expression profile and promoter analysis of HEPIS

Human embryo lung cellular protein interacting with severe acute respiratory syndrome-coronavirus nonstructural protein-10 (HEPIS) is a novel transcriptional repressor, the expression profile and promoter activity of which have not been well studied. In the present study, in situ hybridization of RNA was used to study differential HEPIS expression levels in different types of cancer and normal tissues. A total of six truncated lengths of the HEPIS promoter regulatory sequences were cloned into the pGL3-basic vector, and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and dual luciferase reporter assays were performed. The results of RT-qPCR demonstrated that HEPIS expression levels differed across four breast cancer cell lines. The results of the dual luciferase reporter assays revealed that the activities of the reporter gene fragments spanning -1334/+373, -1203/+373, -1060/+373 and -899/+373 bp were higher compared with the reporter gene fragments spanning -759/+373 and -279/+373 bp. A search of the transcription factor database TRANSFAC identified numerous octamer transcription factor-1 (OCT-1), nuclear factor (NF)-κB and C-JUN transcription factor binding sites located on the HEPIS promoter (pHEPIS). Furthermore, the results revealed that mutations of the OCT-1 (-1236/-1223 bp), NF-κB (-1186/-1176 bp) and C-JUN (-856/-846 bp) sites on the human pHEPIS resulted in a decrease in luciferase activity. A chromatin immunoprecipitation assay revealed that OCT-1, NF-κB and C-JUN bound to pHEPIS in a site-dependent manner at the basal state. The TRANSFAC database was used to analyze the pHEPIS of multiple species and several activator protein-1, NF-κB and OCT-1 transcription factor binding sites were predicted. In conclusion, the results of the present study suggest that HEPIS is expressed at different levels in multiple organs and breast cancer cell lines. Furthermore, these findings indicate that OCT-1, NF-κB and C-JUN transcription factors are associated with transcriptional regulation of the HEPIS gene.

Investigation of single and synergic effects of NLRC5 and PD-L1 variants on the risk of colorectal cancer

Constitutive activation of interferon signaling pathways has been reported in colorectal cancer (CRC), leading to a strong CD8+ T cell response through stimulation of NLRC5 expression. Primed CD8+ T cell expansion, however, may be negatively regulated by PD-L1 expression. Additionally, aberrant PD-L1 expression enables cancer cells to escape the immune attack. Our study aimed to select potential regulatory variants in the NLRC5 and PD-L1 genes by using several online in silico tools, such as UCSC browser, HaploReg, Regulome DB, Gtex Portal, microRNA and transcription factor binding site prediction tools and to investigate their influence on CRC risk in a Czech cohort of 1424 CRC patients and 1114 healthy controls. Logistic regression analysis adjusted for age and gender reported a moderate association between rectal cancer risk and two NLRC5 SNPs, rs1684575 T>G (OR: 1.60, 95% CI: 1.13-2.27, recessive model) and rs3751710 (OR: 0.70, 95% CI: 0.51-0.96, dominant model). Given that a combination of genetic variants, rather than a single polymorphism, may explain better the genetic etiology of CRC, we studied the interplay between the variants within NLRC5, PD-L1 and the previously genotyped IFNGR1 and IFNGR2 variants, to evaluate their involvement in the risk of CRC development. Overall we obtained 18 pair-wise interactions within and between the NLRC5 ad PD-L1 genes and 6 more when IFNGR variants were added. Thirteen out of the 24 interactions were below the threshold for the FDR calculated and controlled at an arbitrary level q*<0.10. Furthermore, the interaction IFNGR2 rs1059293 C>T-NLRC5 rs289747 G>A (P<0.0001) remained statistically significant even after Bonferroni correction. Our data suggest that not only a single genetic variant but also an interaction between two or more variants within genes involved in immune regulation may play important roles in the onset of CRC, providing therefore novel biological information, which could eventually improve CRC risk management but also PD-1-based immunotherapy in CRC.

Different N-terminal isoforms of Oct-1 control expression of distinct sets of genes and their high levels in Namalwa Burkitt's lymphoma cells affect a wide range of cellular processes

Oct-1 transcription factor has various functions in gene regulation. Its expression level is increased in several types of cancer and is associated with poor survival prognosis. Here we identified distinct Oct-1 protein isoforms in human cells and compared gene expression patterns and functions for Oct-1A, Oct-1L, and Oct-1X isoforms that differ by their N-terminal sequences. The longest isoform, Oct-1A, is abundantly expressed and is the main Oct-1 isoform in most of human tissues. The Oct-1L and the weakly expressed Oct-1X regulate the majority of Oct-1A targets as well as additional sets of genes. Oct-1X controls genes involved in DNA replication, DNA repair, RNA processing, and cellular response to stress. The high level of Oct-1 isoforms upregulates genes related to cell cycle progression and activates proliferation both in Namalwa Burkitt's lymphoma cells and primary human fibroblasts. It downregulates expression of genes related to antigen processing and presentation, cytokine-cytokine receptor interaction, oxidative metabolism, and cell adhesion, thus facilitating pro-oncogenic processes.

Genome-wide analysis of DNA copy number alterations in early and advanced gastric cancers

To better understand progressive changes in gastric cancer (GC), early and advanced GCs (EGC and AGC, respectively) were examined for copy number alterations (CNAs). A crypt isolation method was used to isolate DNA from tumors and normal glands in 20 AGCs, and fresh tumor samples were obtained from 45 EGCs. We assessed CNAs for differentiated-type GCs using an Infinium HumanCytoSNP-12v2.1 BeadChip in EGCs and AGCs. The most frequent aberrations in EGC were gains at 8q23.3 (42.2%) and 8q23.2 (40%), and loss of heterozygosity (LOH) at 3p14.2 (24.2%), suggesting that these CNAs were involved in the development of EGC. On the other hand, the highest frequencies of gains in AGC were found at 8q24.21 (65%) and 8q24.3 (60%). The most frequent LOHs in AGC were at 11q24.3-25, 11q23.2-24.1, 11q14.1, and 12p11.21-13.33, whereas that in EGC was at 3p14.2. In addition, regions of copy-neutral LOHs in AGC were detected at 11q21, 11q13.3-14.3, 11q11, 11p13-15.3, 12q21.1, 12q12-13.3 and 5q33.3-35.1. Comparisons of gains in EGC and AGC showed significant differences at 12q22-q23.2, 12q21.33, 11p12, 11p14.1, 12q21.31-32.32, 3p12.3, 3p14.1, 10p15.1, 1q24.2 and 2q12.1. Copy neutral LOHs were significantly higher in AGC than in EGC at 14q32.11-32.33, 14q21.3, 14q11.2, 5q11.2, 5q 13.3, 14q21.1-23.2, 14q13.2-13.3, 5q12.1-12.3, 5q11.1, and 17p13.3. The total lengths of the CNAs were significantly greater in AGC than in EGC. We found that the pattern of CNAs in AGC was quite different from that in EGC. We suggest that increasing numbers of CNAs are associated with disease progression from EGC to AGC. © 2016 Wiley Periodicals, Inc.

The Oct1 transcription factor and epithelial malignancies: Old protein learns new tricks

The metazoan-specific POU domain transcription factor family comprises activities underpinning developmental processes such as embryonic pluripotency and neuronal specification. Some POU family proteins efficiently bind an 8-bp DNA element known as the octamer motif. These proteins are known as Oct transcription factors. Oct1/POU2F1 is the only widely expressed POU factor. Unlike other POU factors it controls no specific developmental or organ system. Oct1 was originally described to operate at target genes associated with proliferation and immune modulation, but more recent results additionally identify targets associated with oxidative and cytotoxic stress resistance, metabolic regulation, stem cell function and other unexpected processes. Oct1 is pro-oncogenic in multiple contexts, and several recent reports provide broad evidence that Oct1 has prognostic and therapeutic value in multiple epithelial tumor settings. This review focuses on established and emerging roles of Oct1 in epithelial tumors, with an emphasis on mechanisms of transcription regulation by Oct1 that may underpin these findings. This article is part of a Special Issue entitled: The Oct Transcription Factor Family, edited by Dr. Dean Tantin.