Tumorigenesis Of Colorectal Carcinoma Research Articles

N6-methyladenosine methyltransferase KIAA1429 elevates colorectal cancer aerobic glycolysis via HK2-dependent manner

ABSTRACT Emerging evidence has emphasized the critical roles played by N6-methyladenosine RNA (m6A) modification in colorectal carcinoma (CRC) initiation and progression. However, the roles and mechanism of m6A and KIAA1429 in CRC progression require further clarification. Here, our research aimed to investigate the functions of KIAA1429 in CRC tumorigenesis. Results indicated that KIAA1429 up-regulation closely correlated to the poor prognosis of CRC patients. Bio-functional assays demonstrated that KIAA1429 promoted the aerobic glycolysis, including glucose uptake, lactate production, ATP generation and extracellular acidification rate (ECAR). Mechanistically, KIAA1429 positively up-regulated HK2 level via increasing its mRNA stability by binding the m6A site of HK2 mRNA via m6A-independent manner. Collectively, our work indicates that KIAA1429 has the potential to promote CRC carcinogenesis by targeting HK2 via m6A-independent manner, providing insight into the critical roles of m6A in CRC.

Cellular Immune Signal Exchange From Ischemic Stroke to Intestinal Lesions Through Brain-Gut Axis.

As a vital pivot for the human circulatory system, the brain-gut axis is now being considered as an important channel for many of the small immune molecules’ transductions, including interleukins, interferons, neurotransmitters, peptides, and the chemokines penetrating the mesentery and blood brain barrier (BBB) during the development of an ischemic stroke (IS). Hypoxia-ischemia contributes to pituitary and neurofunctional disorders by interfering with the molecular signal release and communication then providing feedback to the gut. Suffering from such a disease on a long-term basis may cause the peripheral system’s homeostasis to become imbalanced, and it can also lead to multiple intestinal complications such as gut microbiota dysbiosis (GMD), inflammatory bowel disease (IBD), necrotizing enterocolitis (NEC), and even the tumorigenesis of colorectal carcinoma (CRC). Correspondingly, these complications will deteriorate the cerebral infarctions and, in patients suffering with IS, it can even ruin the brain’s immune system. This review summarized recent studies on abnormal immunological signal exchange mediated polarization subtype changes, in both macrophages and microglial cells as well as T-lymphocytes. How gut complications modulate the immune signal transduction from the brain are also elucidated and analyzed. The conclusions drawn in this review could provide guidance and novel strategies to benefit remedies for both IS and relative gut lesions from immune-prophylaxis and immunotherapy aspects.

Regulation of KRAS protein expression by miR-544a and KRAS-LCS6 polymorphism in wild-type KRAS sporadic colon adenocarcinoma.

Colorectal carcinoma (CRC) results from the accumulation of genetic mutations and alterations in signaling pathways. KRAS is mutated in 40% of CRC cases and is involved in increased tumor cells proliferation and survival. Although KRAS mutations are a dominant event in CRC tumorigenesis, increased wild-type KRAS expression has a similar effect on accelerated tumor growth. In this study, we investigated the KRAS status in correlation with clinicopathological features in sporadic CRC and more importantly the role of let-7a-5p and miR-544a-3p in the regulation of wild-type KRAS protein expression in the tumor center (T1) and invasive tumor front (T2). Analysis showed that 39.1% of tumor samples had KRAS mutations. In wild-type KRAS tumors, 62.0% were positive for KRAS protein expression and there was a higher percentage of KRAS-positive tumor cells and a higher intensity of immunohistochemical reaction in T2 than in T1 samples. This could not be attributed to differences in KRAS mRNA levels, suggesting regulation via miR-544a-3p expression which was significantly decreased in T2 samples. Furthermore, we demonstrated that tumor samples carrying the KRAS-LCS6 variant allele had significantly higher protein expression of the wild-type KRAS. Our results suggest the role of the KRAS-LCS6 polymorphism and miR-544a-3p expression in the regulation of wild-type KRAS protein expression in sporadic CRC.

Ubiquitin Specific Protease 29 Functions as an Oncogene Promoting Tumorigenesis in Colorectal Carcinoma.

Simple SummaryAmong other cancers, colorectal carcinoma (CRC) is one of the foremost causes of death worldwide. The mortality rate of those having CRC has increased dramatically in the past few years. Identification of novel regulatory molecules contributing to the progression of CRC remains a focus of significant interest. The oncogenic role of USP29 has recently been explored in a few cancer types. However, evidence concerning the expression of USP29 in other cancers is currently lacking. We identified that USP29 is highly expressed in CRC and may contribute to the progression of CRC. Depletion of USP29 in HCT116 by CRISPR-Cas9 system reduced the growth of cancer cells. Furthermore, our data suggests that USP29 knockdown reduced the tumor volume of mouse xenograft models. Future investigations are required to validate the outcome of USP29-targted therapy in patients having CRC.Colorectal carcinoma is the third foremost cause of cancer-related deaths and accounts for 5.8% of all deaths globally. The molecular mechanisms of colon cancer progression and metastasis control are not well studied. Ubiquitin-specific protease 29 (USP29), a deubiquitinating enzyme, is involved in the occurrence and development of wide variety of cancers. However, its clinical significance and biological roles in colorectal carcinoma (CRC) remain unexplored. In this research, we observed that the rate of USP29 overexpression was higher in colon cancer patient tissues relative to its corresponding normal tissues. CRISPR-Cas9-mediated depletion of USP29 triggered DNA double strand breaks and delayed cell-cycle progression in HCT116 cells. We also demonstrated that USP29 depletion hampers the colony formation and increases apoptosis of HCT116 cells. USP29 knockdown significantly decreased CRC cell proliferation in vitro. Depletion of USP29 in HCT116 cells substantially reduced the tumor volume of mouse xenografts. In conclusion, our study shows that elevated expression of USP29 promotes malignancy in CRC, suggesting that USP29 could be a promising target for colon cancer therapy.

Membrane-cytoplasm translocation of annexin A4 is involved in the metastasis of colorectal carcinoma.

Annexin A4 (ANXA4) is a Ca2+- and phospholipid-binding protein that belongs to the annexin family, which is involved in the development of multiple tumour types via NF-κB signalling. In this study, we verified the high expression and membrane-cytoplasm translocation of ANXA4 in colorectal carcinoma (CRC). Calcium/calmodulin-dependent protein kinase II gamma (CAMK2γ) was found to be important for high ANXA4 expression in CRC, whereas carbonic anhydrase (CA1) promoted ANXA4 aggregation in the cell membrane. An increased Ca2+ concentration attenuated the small ubiquitin-like modifier (SUMO) modification of cytoplasmic ANXA4 and ANXA4 stabilization, and relatively high expression of ANXA4 promoted CRC tumorigenesis and epithelial-mesenchymal transition (EMT).

Hypermethylation of heparanase 2 promotes colorectal cancer proliferation and is associated with poor prognosis

BackgroundThe epigenetic abnormality of tumor-associated genes contributes to the pathogenesis of colorectal carcinoma (CRC). However, methylation in colorectal cancer is still poorly characterized.MethodBy integration of DNA methylation data from the GEO database and gene expression data from The Cancer Genome Atlas database, the aberrantly methylated genes involved in CRC tumorigenesis were identified. Subsequent in vitro experiments further validated their role in CRC.ResultsWe performed integrative genomic analysis and identified HPSE2, a novel tumor suppressor gene that is frequently inactivated through promoter methylation in CRC. K-M survival analysis showed that hypermethylation–low expression of heparanase 2 (HPSE2) was related to poor patient prognosis. Overexpression of HPSE2 reduced cell proliferation in vivo and in vitro. HPSE2 could regulate the p53 signaling pathway to block the cell cycle in G1 phase.ConclusionHPSE2, a novel tumor suppressor gene that is frequently inactivated through promoter methylation in CRC. HPSE2 performs a tumor suppressive function by activating the p53/ p21 signaling cascade. The promoter hypermethylation of HPSE2 is a potential therapeutic target in patients with CRC, especially those with late-stage CRC.

IGFBP3 gene promoter methylation analysis and its association with clinicopathological characteristics of colorectal carcinoma.

Promoter methylation mediated silencing of tumor suppressor genes plays an important role in the tumorigenesis of colorectal carcinoma (CRC). Tumor suppressor gene, Insulin-like Growth Factor Binding Protein-3 (IGFBP-3) expression is frequently downregulated in CRC due to promoter methylations. The aim of this study was to analyze the methylation status of IGFBP-3 gene promoter in stage II and III of CRC cases; find its association with clinicopathological characteristics of CRC patients and the methylation patterns as a prognostic biomarker. 58 histopathologically confirmed cases of CRC were included in the study. Methylation status of IGFBP-3 gene promoter was determined by using methylation specific PCR (MS-PCR) and bisulfite sequencing. Kaplan-Meier survival curve and univariate cox regression analysis were used for survival analysis; Chi-square test used for association analysis. IGFBP3 promoter methylation was found in 37 (63.8%) out of 58 CRC cases. This promoter methylation status was significantly associated with lymph-node metastasis (P = 0.013) and the survival period. In stage II CRC cases, unmethylated gene promoter status showed better survival than the methylated. Mean overall survival (OS) of methylated and unmethylated group was 22.23months, and 49.15months respectively (P = 0.045), HR = 6.432, 95% CI 0.986-41.943. The IGFBP-3 promoter methylations found in 63.8% CRC cases in this study. The methylations was found to be associated with lymph-node metastasis and overall survival of the patients particularly in stage II CRC patients. However, promoter methylation was not associated with other clinocopathological characteristics such as age, gender, tumor location etc.

EHF promotes colorectal carcinoma progression by activating TGF-β1 transcription and canonical TGF-β signaling.

ETS homologous factor (EHF) plays a critical function in epithelial cell differentiation and proliferation. However, the roles of EHF in cancer remain largely unknown. In the present study, we investigated the expression levels, precise function and mechanism of EHF in colorectal carcinoma (CRC). We observed significantly elevated EHF expression in CRC cell lines and tissues. EHF overexpression correlated positively with poor differentiation, advanced T stage, and shorter overall survival of CRC patients. Function experiments revealed that EHF overexpression promoted CRC cell proliferation, migration, and invasion in vitro and in vivo. Mechanistically, EHF could directly upregulate transforming growth factor β1 (TGF‐β1) expression at the transcription level, thereby activating canonical TGF‐β signaling. Our findings provide novel insights into the mechanisms of EHF in tumorigenesis, invasion, and metastasis of CRC, which may help to provide new therapeutic targets for CRC intervention.

POTEE promotes colorectal carcinoma progression via activating the Rac1/Cdc42 pathway

Current studies have shown that POTE ankyrin domain family members have high expressions as tumor antigens in malignant tumors, such as prostate cancer, ovarian cancer, breast cancer and the like. POTEE is a member of the POTE anchor protein family E. However, its role in colorectal carcinoma (CRC) has not been studied. In this study, the function of POTEE in CRC was examined for the first time and its correlation with CRC cell biological behaviors was analyzed. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR), western blotting, and immunohistochemistry revealed that POTEE was remarkably overexpressed in CRC and associated with an aggressive phenotype. We also found that POTEE was localized in the cytoplasm. In addition, downregulation of POTEE expression can notably inhibit the proliferation, migration, and invasion of CRC cell in vitro, and repressed tumor growth and metastasis in vivo. In contrast, overexpression of POTEE could promote the aggressive behaviors of CRC cells. Mechanistically, POTEE promoted CRC migration, invasion and epithelial-mesenchymal transition (EMT) by increasing the activation of Rac1 and Cdc42. To summarize, these results suggested that POTEE might serve as an oncogene for CRC tumorigenesis and progression, and may become a novel molecular marker for clinical diagnosis and treatment.

The association of aberrant expression of NLRP3 and p-S6K1 in colorectal cancer

Colorectal carcinoma (CRC) is one of the most common malignancies worldwide, and except for surgery, treatments effects are limited. Recently, NLRP3 has been reported as an activator in the tumorigenesis of CRC. However, the function and mechanism of NLRP3 in CRC remains elusive. In this study, we revealed that NLRP3 was elevated in CRC tissues and related to clinical factors, such as lymph node invasion and tumor-node-metastasis (TNM) stage. Moreover, NLRP3-positive patients had a poor prognosis. Furthermore, univariate and multivariate analysis revealed that NLRP3 expression was an independent prognostic factor for the survival of CRC patients. We investigated whether NLRP3 linked with the mTOR-S6K1 pathway. The expression of p-S6K1 was upregulated in CRC tissues and NLRP3 expression level was positively associated with the p-S6K1 level. Thus, targeting NLRP3 may be promising for targeted therapy of CRC, especially for mTORC1-targeted resistant patients.

Long noncoding RNA LRRC75A-AS1 inhibits cell proliferation and migration in colorectal carcinoma.

With the continuous improvement of technology in the molecular field, more and more evidence indicated that long noncoding RNAs (lncRNAs) are widely expressed in a broad spectrum of human tumors, playing an important role in the development and progression of tumors. Most studies reported that lncRNAs might serve as reliable biomarkers and effective clinical therapeutic target. Leucine-rich repeat containing 75 A-antisense RNA1 (LRRC75A-AS1) was reported to be relevant to many types of cancers and indicated to do influence on colorectal carcinoma (CRC). This research firstly examined the role of LRRC75A-AS1 in CRC and analyzed its association with the biological behaviors of CRC cells. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) brought to light that LRRC75A-AS1 was remarkably expressed at low levels in CRC tissues. We also found that LRRC75A-AS1 was localized in the cytoplasm. In addition, LRRC75A-AS1 knockdown also notably promoted CRC cell proliferation, metastasis, invasion, and colony formation. To summarize, these experimental results showed that LRRC75A-AS1 might serve as an anti-oncogene for CRC tumorigenesis and advancement, and it may become a novel molecular marker for clinical diagnosis. Impact statement It is reported that colorectal cancer has seriously threatened human health. The incidence of colorectal cancer in China is increasing year by year. At present, the treatment of cancer is gradually developing towards individualized treatment whose core is targeted therapy, and molecular pathology is the basis of targeted therapy. Previous studies have shown that in addition to protein-coding genes that regulate tumor invasion and metastasis, there are also some non-coding genes involved in tumor encroachment and spread. Our study found that long noncoding RNA LRRC75A-AS1 is closely related to CRC and is related to its proliferation and migration. And it may become a novel molecular marker for clinical diagnosis and treatment.

Activation and Expression of Peroxisome Proliferator-Activated Receptor Alpha Are Associated with Tumorigenesis in Colorectal Carcinoma.

Peroxisome proliferator-activated receptor alpha (PPAR-α) belongs to the PPAR family and plays a critical role in inhibiting cell proliferation and tumorigenesis in various tumors. However, the role of PPAR-α in colorectal tumorigenesis is unclear. In the present study, we found that fenofibrate, a PPAR-α agonist, significantly inhibited cell proliferation and induced apoptosis in colorectal carcinoma cells. In addition, PPAR-α was expressed in the nucleus of colorectal carcinoma cells, and the expression of nuclear PPAR-α increased in colorectal carcinoma tissue compared with that of normal epithelium tissue (P<0.01). The correlation between the expression of nuclear PPAR-α and clinicopathological factors was evaluated in human colorectal carcinoma tissues, and the nuclear expression of PPAR-α was significantly higher in well-to-moderately differentiated adenocarcinoma than in mucinous adenocarcinoma (P<0.05). These findings indicate that activation of PPAR-α may be involved in anticancer effects in colorectal carcinomas, and nuclear expression of PPAR-α may be a therapeutic target for colorectal adenocarcinoma treatment.

Abstract 195: SPARCL1 is an angiocrine inhibitor of tumorigenesis in colorectal carcinoma

Abstract Colorectal carcinoma (CRC) is the second leading cause of cancer-related mortality worldwide. The contribution of the tumor microenvironment (TME) to CRC pathogenesis is well established, whereby the dominance of one immune response (Th1) over another (Th17) can yield opposite effects on patient prognosis. We recently reported on TME-dependent vascular plasticity in CRC and identified the secreted protein, acidic and rich in cysteine-like 1 (SPARCL1) as a marker thereof. SPARCL1 is a matricellular protein expressed and secreted exclusively by the vascular system (endothelial and mural cells). In previous studies, gene expression analyses in CRC tumor tissues of different patient cohorts congruently showed a significant loss of SPARCL1 in colon and rectum adenocarcinomas as compared to uninvolved colon tissues and indicated that this loss is TME-dependent. Specifically, high SPARCL1 expression was associated with a Th1-TME, reduced incidence of distant metastasis and increased cancer-related survival. In contrast, SPARCL1 expression was lost in aggressive CRC with a non-Th1-TME. Here we show in functional analyses that SPARCL1 inhibits angiogenesis in different in vitro (endothelial cell proliferation, capillary formation on matrigel, 3D spheroid sprouting), ex vivo (fetal mouse metatarsal explant) and in vivo (FITC-dextran vascular permeability) assays. Moreover, increased tumor cell colonization is detected in the lungs of SPARCL1-knockout mice, further consolidating the anti-tumorigenic function of SPARCL1. To characterize the molecular mechanism of SPARCL1 anti-angiogenic function, we identified the TGF-β co-receptor Endoglin as a cellular receptor for SPARCL1 and found that SPARCL1 regulates ERK1/2 activity. The RAS-ERK pathway is amplified in more than half of all CRC tumors and as such is considered an important therapeutic target. Interestingly, SPARCL1 regulates ERK1/2 not only through phosphorylation but also through its subcellular localization. We show that SPARCL1 induces ERK1/2 phosphorylation preferentially in the cytoplasm and activates specifically cytoplasmic substrates downstream of it. Finally, we show that the regulation of ERK1/2 by SPARCL1 is not limited to endothelial cells but extends to epithelial CRC cells, indicative of autocrine and paracrine functions of SPARCL1. In summary, our study indicates that SPARCL1 is a TME-dependent angiocrine tumor suppressor in CRC acting through the regulation of ERK1/2 activity. This finding opens novel perspectives elucidating the crosstalk between the TME and the ERK signaling pathway and accordingly may enable new strategies to overcoming drug resistance and/or therapy-oriented patient stratification. Citation Format: Clara Tenkerian, Daniela Regensburger, Victoria Langer, Anika Klingler, Anne Borau, Heinrich Sticht, Andreas Ramming, Thomas Wohlfahrt, Benjamin Schmid, Valérie Méniel, Robert Grützmann, Nathalie Britzen-Laurent, Vera Schellerer, Michael Stürzl, Elisabeth Naschberger. SPARCL1 is an angiocrine inhibitor of tumorigenesis in colorectal carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 195.

Abstract 5162: Role of IFN-gamma-activation of distinct tumor and stromal cell populations in colorectal carcinoma pathogenesis

Abstract Tumor and stromal cell plasticity induced by different tumor microenvironments (TMEs) has a significant impact on tumorigenesis of colorectal carcinoma (CRC). Specifically the role of the immunological TME has been investigated intensively. The prognosis of CRC is influenced by the density and localization of infiltrating T cells. Moreover, the presence of an mRNA expression profile indicative of a type 1 adaptive immune response (high IFN-γ and IFN-induced gene expression, cytotoxic T cell (CTL) signature) represents a positive prognostic factor for patients with CRC. IFN-γ is a major mediator of the Th1 immune response, which is produced by NK, NKT, Th1 cells and CTL. The role of IFN-γ in anti-tumor immune response has been mainly attributed to the immune-modulatory activity of the cytokine, such as the recruitment and activation of cytotoxic T-cells or monocytes. However, the expression of the IFN-γ receptor is ubiquitous and studies of IFN-γ-induced genes expression in CRC revealed that many different cell types are stimulated by the cytokine within a tumor, including tumor cells and stromal cells such as macrophages/monocytes and endothelial cells. In vitro, IFN-γ shows anti-tumorigenic activities in CRC cell lines, activates monocytes and exerts potent anti-angiogenic effects on endothelial cells. Here we investigated the cell-type-specific impact of the response to IFN-γ on CRC development using mouse strains with conditional knock-out of the IFN-γ receptor in intestinal epithelial cells (Villin-Cre), T-cells (CD4-Cre), myeloid cells (CD11b-Cre) and endothelial cells (Tie2-Cre + BMT). Tumor growth was chemically induced by injection of azoxymethane combined with three cycles of treatment with dextran-sodium sulfate. This model recapitulates inflammation-induced carcinogenesis. Our results revealed increased tumor numbers and load when the IFN-γ response was blocked in epithelial cells, despite an initial attenuation of inflammation. Tumors that developed in Ifngr2-Villin-Cre mice showed an attenuated IFN-γ response, and a decrease of CD8+ T cell infiltration, cell death and hypoxia. Abrogation of the IFN-γ-response in endothelial cells also fostered tumor growth, which could be attributed to an increase of angiogenesis. Surprisingly, only a modest effect was seen in the T-cell-specific knock-out, in comparison to the myeloid-specific knock-out, which was associated with a strong increase of tumor numbers and load. The latter indicated that the anti-tumorigenic activity mediated by IFN-γ relies to a larger extent on the innate than on the adaptive immune response. Our study documents that the anti-tumorigenic activity of IFN-γ is based on direct effects on epithelial tumor cells and on the vasculature, as well as on the involvement of the innate immune response. Citation Format: Nathalie Britzen-Laurent, Wei Guo, Victoria Langer, Svetlana Khoziainova, Thomas Weisenburger, Thomas H. Winkler, Julia Straube, Maximilian J. Waldner, Christoph Becker, Elisabeth Naschberger, Lisa Skottke, Tripal Philipp, Sergei Grivennikov, Michael Stürzl. Role of IFN-gamma-activation of distinct tumor and stromal cell populations in colorectal carcinoma pathogenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5162.

MicroRNA-202-5p functions as a tumor suppressor in colorectal carcinoma by directly targeting SMARCC1

Recently, microRNAs (miRNAs) have been emerged as critical regulators for human diseases and as prognostic markers in several tumors, including colorectal carcinoma (CRC). Herein, we identified a tumor-suppressive miRNA, miR-202-5p, which may suppress CRC tumorigenesis. SWI/SNF related, matrix associated, actin dependent regulator of chromatin subfamily c member 1 (SMARCC1) is a susceptibility gene in CRC. However, the role of SMARCC1 in CRC tumorigenesis has not been elucidated. In our present study, we demonstrated that miR-202-5p was a tumor-suppressive miRNA in CRC progression. We found that expression of miR-202-5p was obviously decreased in CRC tissues. Down-regulation of miR-202-5p was associated with postoperative survival. Overexpression of miR-202-5p inhibited the growth and metastasis of CRC cells. The SMARCC1 was a direct target of miR-202-5p and promoted the growth and metastasis of CRC cells. Further study showed that SMARCC1 could reverse the inhibitory effect of miR-202-5p on growth and metastasis of CRC cells. In conclusion, our data highlight the key role of miR-202-5p in the progression of CRC. Thus, miR-202-5p may be a potential prognostic marker and of treatment relevance for CRC progression intervention.

STAT1-mediated upregulation of lncRNA LINC00174 functions a ceRNA for miR-1910-3p to facilitate colorectal carcinoma progression through regulation of TAZ

Several of the thousands of human long noncoding RNAs (lncRNAs) have been functionally characterized, yet their potential involvement in colorectal carcinoma (CRC) remains poorly understood. In present study, we aim to investigate the role of lncRNA LINC00174 in CRC carcinogenesis. We observed that increased expression of LINC00174 in CRC tissues and cells in comparison to their corresponding controls. Moreover, the aberrant overexpression of LINC00174 indicated the poor prognosis of CRC patients. Silence of LINC00174 was able to repress CRC cell growth in vitro and in vivo. We first reported that transcription factor STAT1 mediated LINC00174 expression in CRC. In addition, rescue assay was performed to further confirm that LINC00174 contributed to CRC progression by regulating miR-1910-3p/TAZ signal pathway. Taken together, our study discovered the oncogenic role of LINC00174 in clinical specimens and cellular experiments, showing the potential LINC00174/miR-1910-3p/TAZ pathway. This results and findings provide a novel insight for CRC tumorigenesis.

Clinicopathological significance of G9A expression in colorectal carcinoma.

G9A, the primary histone methyltransferase (HMTase) for histone H3 lysine 9, is upregulated in numerous types of cancer and is critical for tumor cell proliferation. The present study aimed to investigate the G9A expression level in colorectal carcinoma (CRC) to evaluate the clinical significance of G9A in CRC. First, the present study detected the expression of G9A protein in 100 pairs of CRC specimens by immunohistochemistry staining and analyzed the correlations between G9A expression and pathological tumor features. It was found that G9A expression was increased markedly in CRC tumor specimens and the high expression was associated with tumor distant metastasis. Oncomine database analysis demonstrated an elevated expression level of G9A in various types of CRC. In total, 6 public available data sets from the Gene Expression Omnibus (GEO) were used and Gene set enrichment analysis (GSEA) was conducted. The results of the bioinformatics analysis demonstrated that high G9A expression was associated with American Joint Committee on Cancer staging, tumor differentiation, tumor relapse of CRC, and may serve a role in CRC cell proliferation. These findings suggested that G9A was overexpressed in CRC and involved in the tumorigenesis and distant metastasis of CRC. The expression level may also serve as a potential indicator for tumor recurrence in CRC. The present findings aided in the understanding of the crucial role of G9A in tumorigenesis and also offered novel ideas for CRC therapy.

SUMOylation of IQGAP1 promotes the development of colorectal cancer

IQGAP1 is a conserved multifunctional protein implicated in tumorigenesis. An aberrant expression of IQGAP1 widely exists in many cancers, but the SUMOylation modification of IQGAP1 in carcinogenesis is unknown by now. Here we first time explore biological functions of IQGAP1 SUMOylation in promoting colorectal cancer progression in vitro and in vivo. The expression of IQGAP1 and its SUMOylation level are both increased in human colorectal carcinoma (CRC) cells and tissues. IQGAP1 is mainly SUMOylated by SUMO1 at the K1445 residue, which could stabilize IQGAP1 by reducing protein ubiquitination. IQGAP1 SUMOylation improves CRC cell growth, cell migration and tumorigenesis in vivo through activating the phosphorylation of ERK, MEK and AKT. While the SUMOylation site mutation at K1445 of IQGAP1 greatly reduces CRC cell proliferation, migration ability and tumor growth of CRC-xenograft mice by suppressing phosphorylation of ERK, MEK and AKT. Our findings discover the IQGAP1 SUMOylation is a novel regulatory mechanism to enhance tumorigenesis and development of CRC in vitro and in vivo.

Knockdown of lncRNA HNF1A-AS1 inhibits oncogenic phenotypes in colorectal carcinoma.

Long non-coding RNAs (lncRNAs) have been demonstrated to serve important roles in the development and progression of cancer. Recently HNF1A antisense RNA 1 (HNF1A-AS1), a lncRNA, has been reported as exhibiting a potential oncogenic role in the development of many types of cancer. However, the expression and the role of HNF1A-AS1 in colorectal carcinoma (CRC) remains unclear. In the present study, the role of HNF1A-AS1 in CRC was examined for the first time and its correlation with CRC cell biological behaviors was analyzed. The results demonstrated that HNF1A-AS1 was distinctly upregulated in CRC tissues and associated with CRC metastasis to the lymph nodes. Reverse transcription-quantitative polymerase chain reaction revealed that HNF1A-AS1 was also upregulated in CRC cell lines and localized in the nucleus. In addition, knockdown of HNF1A-AS1 expression notably inhibited CRC cell proliferation, migration, invasion and colony formation, and suppressed S-phase entry in vitro. Taken together, these results suggested that HNF1A-AS1 might serve as a promising prognostic marker for CRC tumorigenesis and progression.

Alterations in the Β-catenin pathway in non-small cell lung cancer to define a distinct molecular subtype with prognostic and therapeutic implications.

11584 Background: The treatment of non-small cell lung cancer (NSCLC) has been revolutionized by the development of targeted therapy for distinct molecular subsets. Activation of the β-catenin pathway is essential for colorectal carcinoma tumorigenesis and has been implicated in hepatocellular, thyroid and ovarian cancer. The β-catenin pathway is involved in the cell adhesion complex and Wnt signaling. While mutations in this pathway have been reported in NSCLC and β-catenin overexpression correlates with worse survival, its role in lung tumorigenesis is poorly understood. Methods: We performed targeted next generation sequencing using the Ion Torrent Hotspot Cancer Panel v.2 on tumor tissue from 244 NSCLC patients in which we have defined key demographic and clinical parameters including stage and survival. This cohort contained 91 Stage I cases with mRNA expression data using an Illumina platform. Co-occurrence of genes in the β-catenin pathway and 27 other genes in the panel were assessed by Fisher’s exact test, with Benjamini-Hochberg adjustment for multiple comparisons. Results: Seventeen of 244 tumors had mutations in the β-catenin pathway (APC, CTNNB1, and NOTCH1): 10/170 non-squamous NSCLC (6%, 95% CI 3%-10%), and 7/70 squamous NSCLC (10%, 95% CI 5%-19%). The rate of EGFR and RB1 mutations was higher in tumors with b-catenin pathway mutation (5/17 and 2/17) than in those without (13/227 and 0/227, adjusted p = 0.06 for both). The presence of an APC mutation was also associated with higher mRNA expression of the pro-survival protein, BCL2 (n = 91; 5/41 vs. 0/50, unadjusted p = 0.022, adjusted p = 0.3). Furthermore, APC mutations were more frequently observed in tumors with higher levels of EMT markers (high VIM 8% vs. low VIM 0%, unadjusted p = 0.16) and EMT transcription factors (10% vs. low expression 2%, unadjusted p = 0.16). Finally, we observed a trend toward worse overall survival in non-squamous tumors with mutations in the β-catenin pathway (n = 170, log rank test p = 0.07). Conclusions: These studies suggest that tumors with b-catenin pathway alterations are defined by a more mesenchymal and potentially drug resistant subtype which portends a poor prognosis.