Colorectal Carcinoma Malignancies Research Articles

BRD4-binding enhancer promotes CRC progression by interacting with YY1 to activate the Wnt pathway through upregulation of TCF7L2

Colorectal carcinoma (CRC), one of the most life-threatening cancer types, is associated with aberrant expression of epigenetic modifiers and activation of the Wnt pathway. However, the role of epigenetic regulators in driving cancer cell proliferation and their potential as therapeutic targets affecting the Wnt pathway remain unclear. In this study, BRD4 was found to promote the progression of CRC both in vitro and in vivo. The expression of BRD4 correlated with shortened CRC patient survival. In addition, BRD4 function was strongly correlated with the Wnt pathway, but rather through regulation of TCF7L2 at transcriptional levels. BRD4 and H3K27ac have overlapping occupancies in the cis-regulatory elements of TCF7L2, suggesting enhancer-based epigenetic regulation. Numerous YY1 binding sites were found in the abovementioned region. YY1 recruited BRD4 to bind to cis-regulatory elements of TCF7L2, thereby regulating the expression of TCF7L2. Altogether, this study validates that BRD4 performs a canonical epigenetic regulatory function in CRC and can be used in the treatment of Wnt pathway-dependent CRC or other malignancies with clinically available bromodomain inhibitors.

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.

Fusobacterium nucleatum Facilitates M2 Macrophage Polarization and Colorectal Carcinoma Progression by Activating TLR4/NF-κB/S100A9 Cascade.

Fusobacterium nucleatum (Fn) has been considered as a significant contributor in promoting colorectal carcinoma (CRC) development by suppressing host anti-tumor immunity. Recent studies demonstrated that the aggregation of M2 macrophage (Mφ) was involved in CRC progress driven by Fn infection. However, the underlying molecular mechanisms are poorly characterized. Here, we investigated the role of Fn in Mφ polarization as well as its effect on CRC malignancy. Fn infection facilitated differentiation of Mφ into the M2-like Mφ phenotype by in vitro study. Histological observation from Fn-positive CRC tissues confirmed the abundance of tumor-infiltrating M2-like Mφ. Fn-induced M2-like Mφ polarization was weakened once inhibiting a highly expressed damage-associated molecular pattern (DAMP) molecule S100A9 mainly derived from Fn-challenged Mφ and CRC cells. In addition, Fn-challenged M2-like Mφ conferred CRC cells a more malignant phenotype, showing stronger proliferation and migration characteristics in vitro and significantly enhanced tumor growth in vivo, all of which were partially inhibited when S100A9 was lost. Mechanistic studies further demonstrated that activation of TLR4/NF-κB signaling pathway mediated Fn-induced S100A9 expression and subsequent M2-like Mφ activation. Collectively, these findings indicate that elevated S100A9 in Fn-infected CRC microenvironment participates in M2-like Mφ polarization, thereby facilitating CRC malignancy. Furthermore, targeting TLR4/NF-κB/S100A9 cascade may serve as promising immunotherapeutic strategy for Fn-associated CRC.

ALKBH2 inhibition alleviates malignancy in colorectal cancer by regulating BMI1-mediated activation of NF-\u03baB pathway

BackgroundThe alkB homolog 2, alpha-ketoglutarate-dependent dioxygenase (ALKBH2) gene is involved in DNA repair and is expressed in different types of malignancies. However, the role of ALKBH2 in colorectal carcinoma (CRC) remains unclear. This study aimed to explore the potential mechanism of ALKBH2 and its function in CRC.MethodsThe expression levels of ALKBH2 in CRC tissues and cells were determined by qRT-PCR. Following that, the role of ALKBH2 in cell proliferation, invasion, and epithelial-mesenchymal transition (EMT) in CRC cells (Caco-2 and LOVO) were assessed by Cell Counting Kit-8 (CCK-8), transwell assays, and Western blotting, respectively. The effect of ALKBH2 on B cell-specific Moloney murine leukemia virus integration site 1 (BMI1) and downstream NF-κB pathway was determined by Western blotting and luciferase reporter assay.ResultsThe expression of ALKBH2 was significantly upregulated both in CRC tissues and cells. Further experiments demonstrated that reduction of ALKBH2 suppressed Caco-2 and LOVO cell proliferation and invasion. Moreover, ALKBH2 knockdown also suppressed EMT, which increased E-cadherin expression and reduced N-cadherin expression. Besides, ALKBH2 silencing inhibited BMI1 expression and reduced nuclear accumulation of the NF-κB p65 protein, as well as the luciferase activity of NF-κB p65. Upregulation of BMI1 reversed the effect of ALKBH2 knockdown on the proliferation and invasion in CRC cells.ConclusionsOur findings suggest that suppression of ALKBH2 alleviates malignancy in CRC by regulating BMI1-mediated activation of NF-κB pathway. ALKBH2 may serve as a potential treatment target for human CRC.

LncRNA MEG3 promotes endoplasmic reticulum stress and suppresses proliferation and invasion of colorectal carcinoma cells through the MEG3/miR-103a-3p/PDHB ceRNA pathway.

LncRNA maternally expressed gene 3 (MEG3) is a potential prognostic and diagnostic biomarker in colorectal carcinoma (CC). However, its cellular functions and mechanism remain not fully uncovered. Relative expression of MEG3, miRNA (miR)-103a-3p, and pyruvate dehydrogenase E1 subunit beta (PDHB) was detected by RT-qPCR and western blotting. Cell proliferation was measured by CCK-8 assay, colony formation assay, and flow cytometry, as well as xenograft tumor assay. Transwell assay examined cell invasion. Endoplasmic reticulum (ER) stress was evaluated by western blotting. Dual-luciferase reporter assay and RNA immunoprecipitation determined the relationship between miR-103a-3p and MEG3 or PDHB. Expression of MEG3 was downregulated in human CC tumor tissues and cells (SW620 and HCT116), accompanied by higher miR-103a-3p and lower PDHB. Restoring MEG3 suppressed cell viability, colony formation ability, and invasion, arrested cell cycle, and induced apoptosis rate in SW620 and HCT116 cells, as well as promoted expression of ER stress-related proteins (GRP78, ATF6, CHOP, caspase-3, and caspase-9). Furthermore, MEG3 overexpression hindered tumor growth and facilitated ER stress in vivo. Molecularly, miR-103a-3p was a target of MEG3, and further targeted PDHB. Similarly, in function, blocking miR-103a-3p suppressed CC in vitro by affecting proliferation, invasion, and ER stress; in addition, restoring miR-103a-3p partially counteracted the suppressive role of MEG3 in CC cells. MEG3 sponged miR-103a-3p to suppress CC malignancy by inducing ER stress and inhibiting cell proliferation and invasion via upregulating PDHB, suggesting a novel MEG3/miR-103a-3p/PDHB ceRNA pathway.

Prognostic Impact of Budding Grade in Patients With Residual Liver Recurrence of Colorectal Cancer After Initial Hepatectomy

Many patients undergoing hepatectomy for colorectal liver metastases (CRLM) experience recurrence. However, no criteria for screening candidates to undergo repeat hepatectomy (RH) for CRLM have been established. Budding, one form by which colorectal carcinoma malignancies are expressed, is a new pathologic index. This study aimed to analyze prognostic factors, including budding, and to provide criteria for screening candidates to undergo RH for recurrent CRLM. Data of 186 consecutive patients who underwent hepatectomy for CRLM between April 2008 and December 2015 were collected. Survival was calculated using the Kaplan-Meier method. Uni- and multivariate analyses were performed to determine factors significantly affecting mortality. Of 186 patients, 131 experienced recurrence after hepatectomy, with 83 of the 131 patients showing recurrence in the liver, and 52 of these 83 patients undergoing primary surgery at the authors' institution and having information on budding grade. In the univariate analysis, preoperative chemotherapy, budding grade, extrahepatic metastases, and number of liver metastases at the time of recurrence were associated with overall survival (OS) for the 52 patients. In the multivariate analysis, budding grade and number of liver metastases at the time of recurrence were associated with OS. The study examined simple prognostic factors that could help to screen patients better for RH. Repeat hepatectomy improved the prognosis for patients with recurrent CRLM. The independent prognostic factors for OS were number of liver metastases at recurrence as a conventional factor and budding grade as a new pathologic factor. With budding used as an index, patients who could benefit from hepatectomy can be screened more precisely.

Interplay of transcription factors STAT3, STAT1 and AP-1 mediates activity of the matrix metallo-proteinase-1 promoter in colorectal carcinoma cells.

Signal Transducers (STATs) 1 and 3 and Activator Protein 1 (AP-1) are transcription factors involved in the development of malignancy in colorectal carcinoma (CRC). Matrix Metalloproteinase 1 (MMP-1) is a protease frequently dysregulated in de-differentiated and invasive cancer cells. Its expression is influenced by STAT and AP-1 transcription factors. We studied their contributions to transcriptional regulation of MMP-1 in colorectal carcinoma (CRC) cells. Both STAT3 and AP-1 contribute individual expression-inducing and additive effects and interact with the MMP-1 promoter. DNA binding of AP-1 protein c-Jun is stimulation-independent but modulated by STAT3 and a STAT recognition DNA element. Activated STAT3 showed a suppressive effect on AP-1-mediated MMP-1 mRNA upregulation as shown by STAT3 knockdown. Surprisingly, activated STAT1 overcame STAT3-dependent repression of AP-1-driven MMP-1 expression. Moreover, combined STAT3, STAT1 and AP-1 activities evoked maximal MMP-1 mRNA levels in a synergistic manner. Our results suggest a dominant role of AP-1 in transcriptional upregulation of MMP-1 in CRC cells which is modulated by joint functions of STAT3 and STAT1. The individual and combinatorial activity of these factors is of diagnostic and prognostic interest.

Sirtuin 7 promotes colorectal carcinoma proliferation and invasion through the inhibition of E-cadherin.

Sirtuin 7 (Sirt7) is a member of the sirtuin protein family and is implicated in various carcinomas; however, the function of Sirt7 in colorectal carcinoma (CRC) remains unclear. The present study aimed to explore the biological function of Sirt7 in CRC tissues and cell lines, and to investigate the potential underlying mechanism by performing reverse transcription-quantitative polymerase chain reaction analyses, western blot analyses, luciferase reporter assays, cell proliferation and invasion assays. It was demonstrated that Sirt7 presented a higher expression in CRC tissues and cell lines compared with that in normal tissues and cells, and this higher expression was correlated with the tumor size, the tumor, node and metastasis stage and distant metastasis. Knockdown of Sirt7 repressed the proliferation ability of SW620 and HCT116 cells in vitro, while ectopic expression of Sirt7 increased the epithelial-mesenchymal transition and invasion in HT29 and SW480 cells. Notably, these functional effects of Sirt7 were exerted through the repression of E-cadherin. Thus, the data of the present study indicated a novel mechanistic role for Sirt7 as an oncogene in CRC malignancy, and Sirt7 may be a potential therapeutic target.

The association of vimentin and fibronectin gene expression with epithelial-mesenchymal transition and tumor malignancy in colorectal carcinoma.

Colorectal cancer is the most common malignancy of the gastrointestinal tract with very high mortality. One of the most distinguishing features for the establishment of an epithelial-mesenchymal transition phenotype is the alteration of mesenchymal markers expression and structural adhesion proteins. We evaluated the significance of vimentin and fibronectin gene expression in relation to invasion and metastasis in CRC patients. Tissue specimens were collected consecutively from forty-five colorectal carcinoma patients during surgeries. Tissues were divided into two separate parts for pathological and molecular assays. In order to histological staging, tissue sections were prepared from formalin-fixed paraffin-embedded blocks and stained with Hematoxylin and Eosin. To quantify gene expression, specimens were dissected and homogenized. Moreover, SW480, SW48, SW948, Caco-2, HT-29 and LS174T as human colon cancer cell lines were obtained and cultured, then molecular analyzing was performed. As results the expression of VIM gene increased in SW480, SW48 and SW948 while it decreased in Caco-2, HT-29 and LS174T. Moreover, FN was up-regulated in Caco-2, HT-29 and SW948, while it was down-regulated in SW480, SW48 and LS174T. In tissues, vimentin and fibronectin expression significantly increased in stromal cells, whereas vimentin decreased in colonic epithelial cells and fibronectin had no significant change. Vimentin and fibronectin expression were changed in tumor tissues. It was found an association between vimentin expression with age and tumor size; over-expression in older age and decreasing in larger tumor size. Furthermore, fibronectin over-expression is correlated to older age and high tumor stages; up-regulation with increasing age and high tumor stages.

3-D visualization and quantitation of microvessels in transparent human colorectal carcinoma [corrected

Microscopic analysis of tumor vasculature plays an important role in understanding the progression and malignancy of colorectal carcinoma. However, due to the geometry of blood vessels and their connections, standard microtome-based histology is limited in providing the spatial information of the vascular network with a 3-dimensional (3-D) continuum. To facilitate 3-D tissue analysis, we prepared transparent human colorectal biopsies by optical clearing for in-depth confocal microscopy with CD34 immunohistochemistry. Full-depth colons were obtained from colectomies performed for colorectal carcinoma. Specimens were prepared away from (control) and at the tumor site. Taking advantage of the transparent specimens, we acquired anatomic information up to 200 μm in depth for qualitative and quantitative analyses of the vasculature. Examples are given to illustrate: (1) the association between the tumor microstructure and vasculature in space, including the perivascular cuffs of tumor outgrowth, and (2) the difference between the 2-D and 3-D quantitation of microvessels. We also demonstrate that the optically cleared mucosa can be retrieved after 3-D microscopy to perform the standard microtome-based histology (H&E staining and immunohistochemistry) for systematic integration of the two tissue imaging methods. Overall, we established a new tumor histological approach to integrate 3-D imaging, illustration, and quantitation of human colonic microvessels in normal and cancerous specimens. This approach has significant promise to work with the standard histology to better characterize the tumor microenvironment in colorectal carcinoma.

Association of malignancy of human colorectal carcinoma with IDO gene expression

Objective To investigate the correlation of Indoleamine 2,3-dioxygenase (IDO) gene expression with malignancy of colorectal carcinoma. Methods The expression of IDO in 121 specimens of colorectal carcinoma, adjacent tissue, and normal mucus tissue was detected by using immunohistochemis-try with anti-IDO monoclone antibody, reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting. The correlation of the expression of IDO with various clinicopathologic characteristics of eolorectal carcinoma was analyzed statistically. Results 35.5% (43/121) of colorectal carcinomas ex-pressed IDO, and the expression of IDO was significantly upregulated in carcinoma as compared with adja-cent or normal mucus tissues. The positive rate of IDO in colorectal carcinoma with low-/un-differentiation, lymphnode or liver metastasis was up to 61.1%, 65.3% and 87.5% respectively, in which more than half was intensively stained (+++). Conclusion The upregulation of IDO gene expression in colorectal carcino-ma was correlated to tumor cell differentiation, clinic stage, and metastasis of the lymph node or liver. IDO may be an indicator of colorectal carcinoma prognosis. The high expression of IDO in the metastatic lymph node implies IDO might have a role in tumor immune escape by catalyzing tryptophan metabolism locally. Key words: Colorectal cancer; Gene expression; Indoleamine 2,3-dioxygenase