Phenotype Of Colorectal Cancer Cells Research Articles

SETBP1 activation upon MDM4-enhanced ubiquitination of NR3C1 triggers dissemination of colorectal cancer cells.

Colorectal cancer (CRC) presents a growing concern globally, marked by its escalating incidence and mortality rates, thus imposing a substantial health burden. This investigation delves into the role of nuclear receptor subfamily 3 group C member 1 (NR3C1) in CRC metastasis and explores the associated mechanism. Through a comprehensive bioinformatics analysis, NR3C1 emerged as a gene with diminished expression levels in CRC. This finding was corroborated by observations of a low-expression pattern of NR3C1 in both CRC tissues and cells. Furthermore, experiments involving NR3C1 knockdown revealed an exacerbation of proliferation, migration, and invasion of CRC cells in vitro. Subsequent assessments in mouse xenograft tumor models, established by injecting human HCT116 cells either through the tail vein or at the cecum termini, demonstrated a reduction in tumor metastasis to the lung and liver, respectively, upon NR3C1 knockdown. Functionally, NR3C1 (glucocorticoid receptor) suppressed SET binding protein 1 (SETBP1) transcription by binding to its promoter region. Notably, mouse double minute 4 (MDM4) was identified as an upstream regulator of NR3C1, orchestrating its downregulation via ubiquitination-dependent proteasomal degradation. Further investigations unveiled that SETBP1 knockdown suppressed migration and invasion, and epithelial to mesenchymal transition of CRC cells, consequently impeding in vivo metastasis in murine models. Conversely, upregulation of MDM4 exacerbated the metastatic phenotype of CRC cells, a propensity mitigated upon additional upregulation of NR3C1. In summary, this study elucidates a cascade wherein MDM4-mediated ubiquitination of NR3C1 enables the transcriptional activation of SETBP1, thereby propelling the dissemination of CRC cells.

Upregulation of GOLPH3 mediated by Bisphenol a promotes colorectal cancer proliferation and migration: evidence based on integrated analysis

BackgroundThe interaction between environmental endocrine-disrupting chemicals, such as Bisphenol A (BPA), and their influence on cancer progression, particularly regarding the GOLPH3 gene in colorectal cancer, remains unclear.MethodsWe performed an integrated analysis of transcriptional profiling, clinical data, and bioinformatics analyses utilizing data from the Comparative Toxicogenomics Database and The Cancer Genome Atlas. The study employed ClueGO, Gene Set Enrichment Analysis, and Gene Set Variation Analysis for functional enrichment analysis, alongside experimental assays to examine the effects of BPA exposure on colorectal cancer cell lines, focusing on GOLPH3 expression and its implications for cancer progression.ResultsOur findings demonstrated that BPA exposure significantly promoted the progression of colorectal cancer by upregulating GOLPH3, which in turn enhanced the malignant phenotype of colorectal cancer cells. Comparative analysis revealed elevated GOLPH3 protein levels in cancerous tissues versus normal tissues, with single-cell analysis indicating widespread GOLPH3 presence across various cell types in the cancer microenvironment. GOLPH3 was also associated with multiple carcinogenic pathways, including the G2M checkpoint. Furthermore, our investigation into the colorectal cancer microenvironment and genomic mutation signature underscored the oncogenic potential of GOLPH3, exacerbated by BPA exposure.ConclusionThis study provides novel insights into the complex interactions between BPA exposure and GOLPH3 in the context of colorectal cancer, emphasizing the need for heightened awareness and measures to mitigate BPA exposure risks. Our findings advocate for further research to validate these observations in clinical and epidemiological settings and explore potential therapeutic targets within these pathways.

Neighboring macrophage-induced alteration in the phenotype of colorectal cancer cells in the tumor budding area.

A higher number of tumor buds in the invasive front of colorectal cancer (CRC) specimens has been shown to contribute to a poor prognosis in CRC patients. Because macrophages (Mφs) have been demonstrated to alter the phenotype of cancer cells, we hypothesized that the phenotype of CRC cells in the tumor budding (TB) area might be changed by the interaction between CRC cells and Mφs. We assessed the expression of topoisomerase 1 in CRC cells to estimate the acquisition of chemoresistance in CRC. To demonstrate the tumor-stromal interaction between CRC cells and Mφs, we assessed two histological findings, the number of Mφs per single CRC cell and the proximity between CRC cells and Mφs by histological spatial analysis using HALO software. The expression levels of topoisomerase 1 in CRC cells were decreased in deeper areas, especially in the TB area, compared to the surface area. Our histological spatial analysis revealed that 2.6 Mφs located within 60μm of a single CRC cell were required to alter the phenotype of the CRC cell. Double-immunofluorescence staining revealed that higher Mφs were positive for interleukin-6 (IL-6) in the TB area and that AE1/AE3-positive CRC cells were also positive for phospho-STAT3 (pSTAT3) in the TB area; thus, the IL-6 receptor (IL-6R)/STAT3 signaling pathway in CRC cells was upregulated by IL-6 derived from neighboring Mφs. IL-6 secreted from the neighboring Mφs would alter the phenotype of CRC cells via IL-6R/STAT3 signaling pathway.

Exosomes derived from cancer-associated fibroblasts promote tumorigenesis, metastasis and chemoresistance of colorectal cancer by upregulating circ_0067557 to target Lin28

BackgroundCancer associated fibroblasts (CAFs) can remodel tumor microenvironment by secreting exosomes. This study aimed to investigate the role of exosomes derived from cancer-associated fibroblasts in colorectal cancer (CRC) progression.MethodsCircular RNA (circRNA) array was used to identify differentially expressed circRNAs in exosomes from normal fibroblasts (NFs) and CAFs, and confirmed one differentially expressed circRNA circ_0067557 by real-time PCR. The effect of circ_0067557 on proliferation, metastasis, chemoresistance and apoptosis was verified by wound heal, tranwell, CCK8, sphere-forming and flow cytometry assay.ResultsCirc_0067557 expression in exosomes from CAFs was higher than those from NFs. CAF-derived exosomes promoted the proliferation, migration, invasion and chemoresistance of CRC cells while suppressed apoptosis. Silencing of circ_0067557 inhibited malignant phenotypes of CRC cells by targeting Lin28A and Lin28B. Moreover, CAF-derived exosomes enhanced the growth of CRC xenograft tumors.ConclusionCirc_0067557/Lin28A and Lin28B signal axis may be a potential therapy target for CRC.

Increased PKN2 and M2-Polarized Macrophages Promote HCT116 Cell Invasion.

Colorectal cancer is the third most common malignant tumor, with highly invasive and metastatic potential in the later stage. This study investigated the role of PKN2 overexpression and M2-polarized macrophages in dictating the malignant phenotype of colorectal cancer cells. HCT116 colorectal cancer cell line with PKN2 overexpression was generated to investigate the functional role of PKN2. THP-1 cells were polarized into M2-like macrophages, and the co-culture system of THP-1/M2 cells and HCT116 cells was established to examine the impacts of M2-polairzed macrophages on the malignant phenotype of colorectal cancer cells. PKN2 overexpression promoted cell proliferation, migration and invasion in HCT116 colorectal cancer cells, and reduced spontaneous cell death in the cell culture. Besides, the presence of M2-polarized THP-1 cells significantly enhanced the aggressive phenotype of HCT116 cells. Both PKN2 overexpression and M2-polarized THP-1 cells increased the expression of NF-κB p65 in HCT116 cells, indicating that enhanced NF-κB signaling may contribute to the augmented aggressiveness of HCT116 cells. These findings suggest PKN2 as an oncogenic factor in colorectal cancer and that M2-polarized THP-1 cells may promote the progression of colorectal cancer by activating NF-κB signaling.

Hsa_circ_0001278 Facilitates Colorectal Cancer Progression via Sponging miR-338-5p and Regulating AMOTL1 Expression.

Colorectal cancer (CRC) ranks as the third most common cancer and is second in terms of mortality worldwide. Circular RNAs are involved in the occurrence and development of malignant tumors by functioning either as oncogenes or tumor suppressors. This study investigated the functions of hsa_circ_0001278 in CRC. We analyzed the expression of hsa_circ_0001278 in CRC tissues and adjacent normal tissues. In order to understand the roles of hsa_circ_0001278 in CRC in terms of cellular biological behavior, in vitro experiments were conducted. A mechanistic study was designed to investigate the regulatory effect of hsa_circ_0001278 on CRC. Hsa_circ_0001278 was found to be significantly upregulated in CRC specimens. The functional analysis indicated that hsa_circ_0001278 promotes aggressive phenotypes of CRC cells. Further mechanistic studies revealed that hsa_circ_0001278 sponges miR-338-5p to regulate angiomotin-like 1 (AMOTL1), thereby facilitating CRC progression. Our results demonstrate that hsa_circ_0001278 promotes malignant behaviors in CRC cells by sponging miR-338-5p to regulate AMOTL1 expression. This suggests that hsa_circ_0001278 may serve as a novel target for CRC treatment.

PF-04449913 Inhibits Proliferation and Metastasis of Colorectal Cancer Cells by Down-regulating MMP9 Expression through the ERK/p65 Pathway.

Colorectal cancer remains a life-threatening malignancy with increasing morbidity and mortality worldwide. Therefore, new and effective anti-colorectal cancer therapeutics are urgently needed. In this study, we have studied the anti-tumor properties and potential mechanisms of PF-04449913. Colorectal cancer cell viability was reduced by PF-04449913 in a dose-dependent manner. The migration and invasion ability of malignant colon cells were attenuated by the drug, as demonstrated by the Transwell test. Moreover, PF-04449913 repressed the phosphorylation levels of ERK and other proteins, and the expression levels of MMP9. The anti-tumor effects of the drug in vivo were demonstrated in BALB/c-nude mice models, and PF-04449913 inhibited the malignant phenotype of colorectal cancer cells, including reduction of tumor size and promotion of apoptosis. At the molecular level, PF-04449913 induced a significant decrease in ERK and p65 protein phosphorylation levels and inhibited MMP9 protein expression. Both in vivo and in vitro results showed PF-04449913 to demonstrate antitumor effects, which have been proposed to be mediated through blockade of the ERK/p65 signaling pathway, and subsequent repression of MMP9 expression. Our study provides a new perspective on the potential clinical application of PF-04449913 in the treatment of colorectal cancer.

Tumor cell-derived exosomes mediating hsa_circ_0001739/lncRNA AC159540.1 facilitate liver metastasis in colorectal cancer.

The current study probed into how tumor cell-derived exosomes (Exos) mediated hsa_circ_0001739/lncRNA AC159540.1 to manipulate microRNA (miR)-218-5p/FTO-N6-methyladenosine (m6A)/MYC signal axis in liver metastasis in colorectal cancer (CRC). hsa_circ_0001739 and lncRNA AC159540.1 were identified as the upstream regulator of miR-218-5p using ENCORI and LncBase databases. Expression patterns of miR-218-5p, hsa_circ_0001739, lncRNA AC159540.1, FTO, and MYC were detected, accompanied by loss-and-gain-of function assays to examine their effects on CRC cell biological functions. SW480 cells-derived Exos were purified, followed by in vitro studies to uncover the effect of hsa_circ_0001739/lncRNA AC159540. miR-218-5p was downregulated while hsa_circ_0001739/lncRNA AC159540.1 was upregulated in CRC tissues and cells. Silencing of hsa_circ_0001739/lncRNA AC159540.1 restrained the malignant phenotypes of CRC cells. Exos-mediated hsa_circ_0001739/lncRNA AC159540.1 competitively inhibited miR-218-5p to elevate FTO and MYC. The inducing role of Exos-mediated hsa_circ_0001739/lncRNA AC159540.1 in CRC was also validated in vivo. Conclusively, Exos-mediated circ_0001739/lncRNA AC159540.1 regulatory network is critical for CRC, offering a theoretical basis for CRC treatment.

Suramin, a drug for the treatment of trypanosomiasis, reduces the prothrombotic and metastatic phenotypes of colorectal cancer cells by inhibiting hepsin

Recently, our group identified serine-protease hepsin from primary tumor as a biomarker of metastasis and thrombosis in patients with localized colorectal cancer. We described hepsin promotes invasion and thrombin generation of colorectal cancer cells in vitro and in vivo and identified venetoclax as a hepsin inhibitor that suppresses these effects. Now, we aspire to identify additional hepsin inhibitors, aiming to broaden the therapeutic choices for targeted intervention in colorectal cancer. MethodsWe developed a virtual screening based on molecular docking between the hepsin active site and 2000 compounds from DrugBank. The most promising drug was validated in a hepsin activity assay. Subsequently, we measured the hepsin inhibitor effect on colorectal cancer cells with basal or overexpression of hepsin via wound-healing, gelatin matrix invasion, and plasma thrombin generation assays. Finally, a zebrafish model determined whether hepsin inhibition reduced the invasion of colorectal cancer cells overexpressing hepsin. ResultsSuramin was the most potent hepsin inhibitor (docking score: −11.9691 Kcal/mol), with an IC50 of 0.66 µM. In Caco-2 cells with basal or overexpression of hepsin, suramin decreased migration and significantly reduced invasion and thrombin generation. Suramin did not reduce the thrombotic phenotype in the hepsin-negative colorectal cancer cells HCT-116 and DLD-1. Finally, suramin significantly reduced the in vivo invasion of Caco-2 cells overexpressing hepsin. ConclusionSuramin is a novel hepsin inhibitor that reduces its protumorigenic and prothrombotic effects in colorectal cancer cells. This suggests the possibility of repurposing suramin and its derivatives to augment the repertoire of molecular targeted therapies against colorectal cancer.

Pro-carcinogenic actions of miR-155/FOXO3a in colorectal cancer development.

Colorectal cancer (CRC) ranks third in cancer incidence and second in cancer mortality globally. MicroRNAs (miRNAs) are promising biomarkers and therapeutic targets for CRC diagnosis and treatment. The miR-155 is reported to induce radiation resistance in CRC. In this study, we aimed to further clarify the role and underlying mechanism of the miR-155 in CRC cell malignancy. We found that miR-155 was significantly up-regulated in CRC tissues. The results of loss-of-function experiments revealed that miR-155 deficiency suppressed the proliferative capacity, invasion, and migration of CRC cells. Moreover, the downstream target genes of miR-155 were screened, and miR-155 was demonstrated to directly bind to FOXO3a in CRC cells to negatively regulate FOXO3a expression. FOXO3a was downregulated in CRC tissues and the expression of FOXO3a and miR-155 was in negative correlation in CRC tissues. FOXO3a overexpression alone was revealed to inhibit CRC cell growth, migration and invasion. Additionally, rescue assays showed that FOXO3a silencing significantly reversed the inhibitory effect of miR-155 deficiency on CRC cell malignant behaviors. In conclusion, miR-155 induces malignant phenotypes of CRC cells including cell proliferation, migration and invasion by targeting FOXO3a, which might provide clues for the targeted therapy of CRC.

RNASEH1-AS1 induced by H3K27ac stabilizes ANXA2 mRNA to promote the progression of colorectal cancer through recruiting BUD13.

Colorectal cancer (CRC) is a malignant tumor with high morbidity and mortality. It is well-accepted that dysregulated lncRNAs are closely related to the development of CRC. In this study, the function and mechanism of RNASEH1-AS1 in CRC were investigated. RT-qPCR and western blot detected the expression of targeted genes in tissues and cells. CCK-8, clone formation, wound healing assay, and Transwell were applied to evaluate CRC cell malignant behaviors. ChIP, RIP, and RNA pull-down validated interactions among RNASEH1-AS1, H3K27ac, CBP, BUD13, and ANXA2. Nucleoplasmic separation and FISH assay determined the location of RNASEH1-AS1 in CRC cells. IHC assay was used to detect Ki-67 expression in tumor tissues from mice. RNASEH1-AS1 was highly expressed in CRC tumor tissues and cells. RNASEH1-AS1 silencing effectively suppressed the viability, proliferation, migration, and invasion of CRC cells. In addition, CBP-mediated H3K27ac increased RNASEH1-AS1 expression in CRC cells and RNASEH1-AS1 could elevate ANXA2 expression through recruiting BUD13. Furthermore, RNASEH1-AS1 silencing inhibited malignant phenotypes of CRC cells and tumor growth in mice through decreasing ANXA2 expression and inactivating the Wnt/β-catenin pathway. Our results revealed that RNASEH1-AS1 induced by CBP-mediated H3K27ac activated Wnt/β-catenin pathway to promote CRC progression through recruiting BUD13 to stabilize ANXA2 mRNA, which provides substantial evidence of RNASEH1-AS1 in CRC. Targeting RNASEH1-AS1 might alleviate CRC progression.

Tumor-suppressive zinc finger protein 24 (ZNF24) sensitizes colorectal cancer cells to 5-fluorouracil by inhibiting the Wnt pathway and activating the p53 signaling

Carcinogenesis and colorectal cancer (CRC) development are associated with dysregulation of various pathways, including Wnt and p53. 5-fluorouracil (5-FU) is a common chemotherapeutic agent for CRC treatment, but its efficacy is restricted by drug resistance. Doxycycline is an orally active tetracycline antibiotic known for its antimicrobial and anticancer cell proliferation activities. This study intends to delineate the potential role of bioinformatically predicted ZNF24 in the 5-FU resistance of CRC cells. The expression of ZNF24 was measured in clinically collected CRC tissues and cells. Afterward, ectopic ZNF24 expression was induced by DOX to evaluate the viability, colony-forming ability and sphere-forming ability of CRC cells. It was found that ZNF24 was validated to be poorly expressed in CRC tissues, and ectopic expression of ZNF24 was revealed to restrict the malignant phenotypes of CRC cells. In addition, restored ZNF24 attenuated 5-FU resistance of CRC cells by inhibiting the Wnt pathway and activating p53 signaling. Furthermore, an inhibitor of Wnt production 2 (IWP-2) treatment was an alternative to ZNF24 up-regulation in sensitizing CRC cells to 5-FU treatment. In conclusion, our results indicate that ZNF24 inhibits 5-FU resistance of CRC cells by suppressing the Wnt pathway and activating p53 signaling, which offers a potential strategy for managing chemoresistance in CRC.

Activation of AKT induces EZH2-mediated β-catenin trimethylation in colorectal cancer

Colorectal cancer (CRC) develops in part through the deregulation of different signaling pathways, including activation of the WNT/β-catenin and PI3K/AKT pathways. Additionally, the lysine methyltransferase enhancer of zeste homologue 2 (EZH2) is commonly overexpressed in CRC. EZH2 canonically represses gene transcription by trimethylating lysine 27 of histone H3, but also has non-histone substrates. Here, we demonstrated that in CRC, active AKT phosphorylated EZH2 on serine 21. Phosphorylation of EZH2 by AKT induced EZH2 to interact with and methylate β-catenin at lysine 49, which increased β-catenin's binding to the chromatin. Additionally, EZH2-mediated β-catenin trimethylation induced β-catenin to interact with TCF1 and RNA polymerase II and resulted in dramatic gains in genomic regions with β-catenin occupancy. EZH2 catalytic inhibition decreased stemness but increased migratory phenotypes of CRC cells with active AKT. Overall, we demonstrated that EZH2 modulates AKT-induced changes in gene expression through the AKT/EZH2/β-catenin axis in CRC.

Targeting proteasomal deubiquitinases USP14 and UCHL5 with b-AP15 reduces 5-fluorouracil resistance in colorectal cancer cells.

5-Fluorouracil (5-FU) is the first-line treatment for colorectal cancer (CRC) patients, but the development of acquired resistance to 5-FU remains a big challenge. Deubiquitinases play a key role in the protein degradation pathway, which is involved in cancer development and chemotherapy resistance. In this study, we investigated the effects of targeted inhibition of the proteasomal deubiquitinases USP14 and UCHL5 on the development of CRC and resistance to 5-FU. By analyzing GEO datasets, we found that the mRNA expression levels of USP14 and UCHL5 in CRC tissues were significantly increased, and negatively correlated with the survival of CRC patients. Knockdown of both USP14 and UCHL5 led to increased 5-FU sensitivity in 5-FU-resistant CRC cell lines (RKO-R and HCT-15R), whereas overexpression of USP14 and UCHL5 in 5-FU-sensitive CRC cells decreased 5-FU sensitivity. B-AP15, a specific inhibitor of USP14 and UCHL5, (1-5 μM) dose-dependently inhibited the viability of RKO, RKO-R, HCT-15, and HCT-15R cells. Furthermore, treatment with b-AP15 reduced the malignant phenotype of CRC cells including cell proliferation and migration, and induced cell death in both 5-FU-sensitive and 5-FU-resistant CRC cells by impairing proteasome function and increasing reactive oxygen species (ROS) production. In addition, b-AP15 inhibited the activation of NF-κB pathway, suppressing cell proliferation. In 5-FU-sensitive and 5-FU-resistant CRC xenografts nude mice, administration of b-AP15 (8 mg·kg-1·d-1, intraperitoneal injection) effectively suppressed the growth of both types of tumors. These results demonstrate that USP14 and UCHL5 play an important role in the development of CRC and resistance to 5-FU. Targeting USP14 and UCHL5 with b-AP15 may represent a promising therapeutic strategy for the treatment of CRC.

SOX9 knockout decreases stemness properties in colorectal cancer cells.

Colorectal cancer (CRC) is a leading cause of death worldwide. SRY-box transcription factor 9 (SOX9) participates in organogenesis and cell differentiation in normal tissues but has been involved in carcinogenesis development. Cancer stem cells (CSCs) are a small population of cells present in solid tumors that contribute to increased tumor heterogeneity, metastasis, chemoresistance, and relapse. CSCs have properties such as self-renewal and differentiation, which can be modulated by many factors. Currently, the role of SOX9 in the maintenance of the stem phenotype has not been well elucidated, thus, in this work we evaluated the effect of the absence of SOX9 in the stem phenotype of CRC cells. We knockout (KO) SOX9 in the undifferentiated CRC cell line HCT116 and evaluated their stemness properties using sphere formation assay, differentiation assay, and immunophenotyping. SOX9-KO affected the epithelial morphology of HCT116 cells and stemness characteristics such as its pluripotency signature with the increase of SOX2 as a compensatory mechanism to induce SOX9 expression, the increase of KLF4 as a differentiation feature, as well as the inhibition of the stem cell markers CD44 and CD73. In addition, SOX9-KO cells gain the epithelial-mesenchymal transition (EMT) phenotype with a significant upregulation of CDH2. Furthermore, our results showed a remarkable effect on first- and second-sphere formation, being SOX9-KO cells less capable of forming high-size-resistant spheres. Nevertheless, CSCs surface markers were not affected during the differentiation assay. Collectively, our findings supply evidence that SOX9 promotes the maintenance of stemness properties in CRC-CSCs.

Cancer-associated fibroblasts-derived exosome-mediated transfer of miR-345-5p promotes the progression of colorectal cancer by targeting CDKN1A.

Colorectal cancer (CRC) is the second leading cause of cancer-induced death in the world. Cancer-associated fibroblasts (CAFs) released exosomes that contributed to cancer progression. This research was carried out to study the influence of CRC-associated fibroblasts-derived exosomes on the phenotype of CRC cells and the underlying mechanism. CAFs-derived exosomes (CAFs-exo) and normal fibroblasts (NFs)-derived exosomes (NFs-exo) were recognized by transmission electronic microscopy, nanoparticle tracking analysis and western blot analysis. Cell counting kit-8, flow cytometry analysis, colony formation assay, Transwell, qRT-PCR, immunofluorescence, immunohistochemistry staining and xenografts model were carried out to proceed with function studies in vitro and in vivo. The results showed that CAFs-exo induced cell proliferation, migration and invasion, while NFs-exo did not influence the tumor biological properties of CRC cells. Using qRT-PCR, miR-345-5p was observed to be a notably up-regulated miRNA in CAFs-exo compared to NFs-exo. CAFs-exo could mediate the transfer of miR-345-5p to CRC cells, and downregulation of miR-345-5p in CAFs notably reversed the pro-tumoral effect of CAFs-exo on CRC cells. Based on online prediction database, CDKN1A was proved as a direct downstream target of miR-345-5p in CRC cells, which was lowly expressed and negatively associated with miR-345-5p in CRC tumors. Furthermore, miR-345-5p upregulation-mediated tumor biological behaviors were abrogated by exogenous CDKN1A. In CRC cells-beared tumor xenograft, CAFs-exo administration promoted tumor growth and decreased CDKN1A expression, whereas miR-345-5p inhibition reversed these effects. The present study revealed that by interacting with CDKN1A, CAF-derived exosomal miR-345-5p promotes CRC progression and metastasis.

LncRNA HOXB-AS4 promotes proliferation and migration of colorectal cancer via the miR-140-5p/hdac7 axis

ABSTRACT Long noncoding RNAs (lncRNA) have a critical role in colorectal cancer (CRC) development and progression. However, the role of the lncRNA HOXB-AS4 in CRC remains unclear. In this study, we found that HOXB-AS4 was markedly upregulated in tumor tissues compared to precancerous tissues. Loss-of-function assays in HT29 and SW480 cells confirmed that knockdown of HOXB-AS4 inhibited proliferation, migration, and promoted apoptosis. In addition, HOXB-AS4 was shown to regulate histone deacetylase 7 (HDAC7) expression by acting as a molecular sponge to bind to and adsorb miR-140-5p. These findings were confirmed by the dual-luciferase reporter assay. Functional recovery experiments further demonstrated the crucial role of the HOXB-AS4/miR-140-5p/HDAC7 axis in modulating the malignant phenotype of CRC cells. Collectively, our data suggested that HOXB-AS4 regulated the malignant tumor aggression of HT29 and SW480 cells through the miR-140-5p/HDAC7 axis and PI3K/AKT signaling pathway. Our study provides novel insights into the mechanism of action of HOXB-AS4 in CRC and highlights its potential use as a targeted therapy.

Circular RNA ACACA negatively regulated p53-modulated mevalonate pathway to promote colorectal tumorigenesis via regulating miR-193a/b-3p/HDAC3 axis.

This study aimed to explore the biological functions and underlying mechanism of circRNA acetyl-CoA carboxylase alpha (circACACA) in colorectal cancer (CRC). The RNA and protein levels were detected by qRT-PCR and western blot assays. The malignant capacities of CRC cells were analyzed by cell counting kit-8 (CCK-8), colony formation, flow cytometry, and transwell assays. The target relationship between miR-193a/b-3p and circACACA/histone deacetylase 3 (HDAC3) was determined by luciferase reporter assay and RNA immunoprecipitation. The binding of HDAC3 to the p53 promoter was validated by chromatin immunoprecipitation (ChIP). CRC cell growth and lung metastasis were evaluated in nude mice in vivo. High expression of circACACA was found in CRC tissues and cells, which was closely associated with the advanced tumor, lymph node, metastasis (TNM) stage, metastasis, and low overall survival rate. circACACA downregulation effectively delayed CRC cell proliferation and metastasis, but triggered apoptosis via inactivating the mevalonic acid (MVA) pathway. However, circACACA overexpression resulted in the opposite effects. Mechanistically, circACACA enhanced HDAC3 expression through sponging miR-193a/b-3p, which activated theMVA pathway via inhibiting the acetylation and transcription of p53. Moreover, rescue experiments confirmed that miR-193a/b-3p inhibition reversed the inhibitory effect of circACACA deficiency on CRC growth and metastasis. Moreover, circACACA overexpression-mediated malignant phenotypes of CRC cells were abrogated by HDAC3 knockdown. circACACA promoted CRC progression via regulating themiR-193a/b-3p/HDAC3/p53 axis to activate theMVA pathway, providing evidence for circACACA as a promising therapeutic target for CRC.

TRAF4-mediated ubiquitination-dependent activation of JNK/Bcl-xL drives radioresistance

The E3 ligase TNF receptor-associated factor 4 (TRAF4) is upregulated and closely associated with tumorigenesis and the progression of multiple human malignancies. However, its effect on radiosensitivity in colorectal cancer (CRC) has not been elucidated. The present study found that TRAF4 was significantly increased in CRC clinical tumor samples. Depletion of TRAF4 impaired the malignant phenotype of CRC cells and sensitized irradiation-induced cell death. Irradiation activated the c-Jun N-terminal kinases (JNKs)/c-Jun signaling via increasing JNKs K63-linked ubiquitination and phosphorylation. Furthermore, c-Jun activation triggered the transcription of the antiapoptotic protein Bcl-xL, thus contributing to the radioresistance of CRC cells. TRAF4 was positively correlated with c-Jun and Bcl-xL, and blocking TRAF4 or inhibiting Bcl-xL with inhibitor markedly promoted ionizing radiation (IR)-induced intrinsic apoptosis and sensitized CRC cells to radiotherapy in vitro and in vivo. Our findings illustrate a potential mechanism of radioresistance, emphasizing the clinical value of targeting the TRAF4/Bcl-xL axis in CRC therapy.

DNMT3b affects colorectal cancer development by regulating FLI1 through DNA hypermethylation.

Friend leukemia integration 1 (FLI1) is an ETS transcription factor family member. Here, we identified cg11017065 as the most hyper-methylated cytosine and guanine (CpG) in colorectal cancer (CRC), which belongs to the FLI1 gene. Moreover, integrated bioinformatics prediction and analysis of our cohort showed that FLI1 expression was downregulated and DNA methylation was elevated in CRC. Bioinformatics prediction also indicated that patients overexpressing FLI1 had higher survival rates than those with low FLI1 expression. CRC cells with ectopic expression of FLI1 had reduced invasion, migration, cloning ability and increased apoptosis. Furthermore, DNA-methyltransferase 3b (DNMT3b) was found to be significantly overexpressed in CRC, and low DNMT3b expression predicted a prolonged survival. DNMT3b bound to the FLI1 promoter. Inhibition of DNMT3b increased FLI1 expression and inhibited the malignant phenotype of CRC cells. Inhibition of FLI1 reversed the phenotypic modulation by DNMT3b depletion in vitro and in vivo. In conclusion, our data indicate that DNMT3b potentiates CRC cell proliferation, migration, and invasion through downregulating FLI1.