Signaling In Colon Cancer Research Articles

Obesity Promotes Marrow-Derived Myeloid Cell Accumulation while Exercise Reduces Proliferative Signaling in Colon Cancer.

Obesity increases colon cancer risk that has been previously linked to marrow-derived myeloid cells. We previously demonstrated that exercise training (EX) prevents colon cancer initiation, potentially through reduced myelopoiesis. However, it remains unknown whether early myeloid cell accumulation and inflammation in the colon precedes carcinogenesis with high-fat diet (HFD)-induced obesity, and if EX can attenuate these effects. We hypothesized that obesity would promote colon carcinogenesis that was preceded by myeloid cell accumulation and inflammation that would be attenuated by EX. C57BL/6 mice were randomized to a HFD or control (CON) diet for 8 weeks. The HFD mice switched to CON diet and all mice were given intraperitoneal injections of azoxymethane (AOM) to induce colon cancer and randomized into EX or sedentary (SED) conditions. HFD mice developed more aberrant crypt foci (ACF), a marker for early carcinogenesis, compared to CON (p < 0.01), and EX developed fewer ACF compared to SED (p < 0.0001). Marrow-derived (p < 0.001) CD206+ macrophages were elevated in HFD compared to CON at study week 16 (p < 0.01). Marrow-derived CD206- macrophages (p < 0.05) and marrow-derived (p < 0.05) CD206+ macrophages were more abundant in HFD compared to CON at study week 42. EX did not alter colon immune cell populations. β-Catenin protein was higher in HFD compared to CON at study week 42 (p < 0.05), and STAT3 protein content was lower at study week 28 with EX compared to SED (p < 0.05). The results suggest that obesity promotes colon ACF formation, potentially through early inflammatory myeloid cell accumulation. Despite attenuating ACF, EX did not alter myeloid cell accumulation in the colon, suggesting that EX inhibits ACF formation through alternative mechanisms which may include reduced β-Catenin and STAT3 signaling.

Interplay between microbial-derived GABA and host GABA receptor signaling collectively influence the tumorigenic function of GABA in colon cancer.

Although classically recognized as a neurotransmitter, gamma aminobutyric acid (GABA) has also been identified in colonic tumors. Moreover, the gut microbiome represents another potential source of GABA. Both GABAA and GABAB receptors have been implicated in contributing to the effects of GABA in colorectal cancer, with both pro- and anti-tumorigenic functions identified. However, their subunit composition is often overlooked. Studies to date have not addressed whether the GABA-producing potential of the microbiome changes over the course of colon tumor development or whether receptor subunit expression patterns are altered in colon cancer. Therefore, we investigated the clusters of orthologous group frequencies of glutamate decarboxylase (GAD) in feces from two murine models of colon cancer and found that the frequency of microbial GAD was significantly decreased early in the tumorigenic process. We also determined that microbial-derived GABA inhibited proliferation of colon cancer cells invitro and that this effect of GABA on SW480 cells involved both GABAA and GABAB receptors. GABA also inhibited prostaglandin E2 (PGE2)-induced proliferation and interleukin-6 (IL-6) expression in these cells. Gene expression correlations were assessed using the "Cancer Exploration" suite of the TIMER2.0 web tool and identified that GABA receptor subunits were differentially expressed in human colon cancer. Moreover, GABAA receptor subunits were predominantly positively associated with PGE2 synthase, cyclooxygenase-2 and IL-6. Collectively, these data demonstrate decreased potential of the microbiome to produce GABA during tumorigenesis, a novel anti-tumorigenic pathway for GABA, and that GABA receptor subunit expression adds a further layer of complexity to GABAergic signaling in colon cancer.

Liquidambaric lactone is a potent inhibitor of TRAF2 for cancer therapy

BackgroundTumor necrosis factor (TNF) receptor-associated factor 2 (TRAF2) is an oncogenic regulator of Wnt/β-catenin signaling in colon cancer. Previously we have reported a pentacyclic triterpenoid compound liquidambaric acid (LDA) inhibiting Wnt/β-catenin signaling via targeting TRAF2, however, LDA inhibition of cancer cells was observed only at high doses. It is important to identify small molecules targeting TRAF2 in colon cancer with higher potency . MethodsMicroscale thermophoresis (MST) assay was used to screen a panel of pentacyclic triterpenoids. Cellular thermal shift assay (CETSA) was used to confirm target engagment in living cells. Drug affinity responsive target stability (DARTS) coupled with mass spectrometry (MS) was used to identify the potential targets of candidate TRAF2 binder. Wnt signaling inhibition was evaluated by 7TGC reporter assay, TOPFlash assay, reverse transcription and real-time quantitative PCR, as well as zebrafish eyeless assay. Cancer inhibition was assessed by cell viability assay, colony formation assay and xenograft studies. CRISPR/Cas9 knockout HCT116 cells was used to assess the requirement of TRAF2 for liquidambaric lactone (LDL) inhibition of cancer. ResultsA LDA analogue LDL selectively targeted TRAF2 with higher binding affinity. Both LDL and LDA targeted the TRAF-C domain of TRAF2 with slightly different binding sites. Of note, LDL showed much stronger inhibition of colon cancer cells than LDA in colony formation assay. LDL inhibition of cancer was also comfirmed in xenograft mice. Depletion of TRAF2 totally blocked LDL inhibition of Wnt signaling, TNF signaling and growth of cancer cells. ConclusionsA natural product LDL is a potent inhibitor of TRAF2 for cancer therapy, and TRAF2 is required for LDL inhibition of cancer.

Acss2/HIF-2 signaling facilitates colon cancer growth and metastasis.

The microenvironment of solid tumors is characterized by oxygen and glucose deprivation. Acss2/HIF-2 signaling coordinates essential genetic regulators including acetate-dependent acetyl CoA synthetase 2 (Acss2), Creb binding protein (Cbp), Sirtuin 1 (Sirt1), and Hypoxia Inducible Factor 2α (HIF-2α). We previously shown in mice that exogenous acetate augments growth and metastasis of flank tumors derived from fibrosarcoma-derived HT1080 cells in an Acss2/HIF-2 dependent manner. Colonic epithelial cells are exposed to the highest acetate levels in the body. We reasoned that colon cancer cells, like fibrosarcoma cells, may respond to acetate in a pro-growth manner. In this study, we examine the role of Acss2/HIF-2 signaling in colon cancer. We find that Acss2/HIF-2 signaling is activated by oxygen or glucose deprivation in two human colon cancer-derived cell lines, HCT116 and HT29, and is crucial for colony formation, migration, and invasion in cell culture studies. Flank tumors derived from HCT116 and HT29 cells exhibit augmented growth in mice when supplemented with exogenous acetate in an Acss2/HIF-2 dependent manner. Finally, Acss2 in human colon cancer samples is most frequently localized in the nucleus, consistent with it having a signaling role. Targeted inhibition of Acss2/HIF-2 signaling may have synergistic effects for some colon cancer patients.

Abstract C053: Differences in hallmark gene sets in the Molecular Signatures Database between tumors from African American and White patients

Abstract To improve cancer outcomes, it is of critical importance to understand biological differences in tumors that ultimately accompany progression to a lethal phenotype. Compared to Whites (Ws), African Americans (AAs) suffer from higher mortality rates for some cancer types, such as prostate and breast cancer. The etiology for these cancer disparities includes an array of attributes related to societal, social, lifestyle, environmental, access and individual, ancestry-related differences. A combination of these etiologies can lead to differences in cancer biology and, therefore, differences in mortality. Differential regulation of various cancer-related pathways in tumor cells can contribute to differential mortality and morbidity outcomes, and influence cancer response to treatment. Therefore, we performed pathway analysis using publicly available gene expression datasets to compare the variation in established cancer-related pathways between tumors from AA and W patients. Molecular Signatures Database (MSigDB) is a widely used database to perform gene enrichment analysis in cancer biology. Using The Cancer Genome Atlas (TCGA) datasets from 18 tumor types and the Gene Set Variation Analysis (GSVA) method, we interrogated MSigDB hallmark gene sets between tumors from AAs and Ws. By comparing the gene set variations in tumors between AAs and Ws, we identified gene sets exhibiting significant (|∆ Z-score| &amp;gt; 2 and p &amp;lt; 0.05) variation by race. For example, our analysis revealed that the variation of 1) MYC targets increases in breast, colon, and uterine cancer from AAs compared to Ws, 2) G2M checkpoint and E2F targets increase in breast and uterine cancer from AAs compared to Ws, and 3) interferon gamma and alpha response and allograft rejection increase in renal clear cell carcinoma from AAs compared to Ws. We also performed survival analysis to identify the MSigDB hallmark gene sets whose variation scores exhibit differential association with overall survival among AA and W patients. Among the gene sets associated differentially by race with overall survival are MYC targets in breast cancer and PI3K AKT MTOR signaling in colon cancer; with variation exhibiting an association with higher overall survival among AA patients compared with W patients. Thus, our analysis reveals how the widely accepted MSigDB hallmark gene sets differ between tumors from AAs and Ws and differentially associate with survival among AA and W patients. The majority of published studies reporting pathways relevant to cancer biology have been based on data from W patients. Therefore, evaluation of hallmark gene sets in cancers from diverse patients has important implications for understanding cancer biology and developing precision medicine interventions. Citation Format: Muthana Al Abo, Daniel J. George, Steven R. Patierno, Jennifer A. Freedman. Differences in hallmark gene sets in the Molecular Signatures Database between tumors from African American and White patients [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr C053.

Activation of DDX58/RIG‑I suppresses the growth of tumor cells by inhibiting STAT3/CSE signaling in colon cancer.

Some patients with colon cancer eventually develop metastasis during treatment, and the 5-year survival rate of patients with metastatic colon cancer remains relatively low, which is most likely due to the ineffectiveness of the current standard treatment. Systemic treatment for patients with colon cancer has expanded from chemotherapy to targeted therapy and immunotherapy. Immunotherapy holds promise in the treatment of colon cancer. The present study revealed the role of innate immune receptor helicase DExD/H-box helicase 58 (DDX58), which encodes retinoic acid-inducible gene-I (RIG-I), in colon cancer. It was demonstrated that colon cancer patients with a low protein expression of DDX58/RIG-I had a worse 5-year survival rate of patients compared with patients with a high expression of DDX58/RIG-I. The activation of DDX58/RIG-I inhibited the proliferation, migration and invasion of colon cancer cells, as well as tumor growth in a nude mouse xenograft model of colon cancer. To investigate the mechanisms of action of DDX58/RIG-I in colon cancer, the role of signal transducer and activator of transcription 3 (STAT3)/cystathionine-γ-lyase (CSE) signaling in the upor downregulation of DDX58 was examined. The data demonstrated that DDX58 regulated the STAT3/CSE signaling pathway by interacting with STAT3 and consequently affecting the proliferation of tumor cells in colon cancer. In addition, the RIG-I agonist, SB9200, induced proliferation, migration and invasion of human colon cancer. On the whole, the present study demonstrates that DDX58/RIG-I affects the proliferation of tumor cells by regulating STAT3/CSE signaling in colon cancer. The findings presented herein suggest that DDX58/RIG-I activation may be an effective treatment strategy, and DDX58/RIG-I agonists may be potential therapeutic candidates for colon cancer.

Activation of Drp1 promotes fatty acids-induced metabolic reprograming to potentiate Wnt signaling in colon cancer.

Cancer cells are known for their ability to adapt variable metabolic programs depending on the availability of specific nutrients. Our previous studies have shown that uptake of fatty acids alters cellular metabolic pathways in colon cancer cells to favor fatty acid oxidation. Here, we show that fatty acids activate Drp1 to promote metabolic plasticity in cancer cells. Uptake of fatty acids (FAs) induces mitochondrial fragmentation by promoting ERK-dependent phosphorylation of Drp1 at the S616 site. This increased phosphorylation of Drp1 enhances its dimerization and interaction with Mitochondrial Fission Factor (MFF) at the mitochondria. Consequently, knockdown of Drp1 or MFF attenuates fatty acid-induced mitochondrial fission. In addition, uptake of fatty acids triggers mitophagy via a Drp1- and p62-dependent mechanism to protect mitochondrial integrity. Moreover, results from metabolic profiling analysis reveal that silencing Drp1 disrupts cellular metabolism and blocks fatty acid-induced metabolic reprograming by inhibiting fatty acid utilization. Functionally, knockdown of Drp1 decreases Wnt/β-catenin signaling by preventing fatty acid oxidation-dependent acetylation of β-catenin. As a result, Drp1 depletion inhibits the formation of tumor organoids in vitro and xenograft tumor growth in vivo. Taken together, our study identifies Drp1 as a key mediator that connects mitochondrial dynamics with fatty acid metabolism and cancer cell signaling.

Interactive Analysis, Exploration, and Visualization of RNA-Seq Data with SeqCVIBE.

The rise of modern gene expression profiling techniques, such as RNA-Seq, has generated a wealth of high-quality datasets spanning all fields of current biological research. The large data sets and the continually expanding applications for which they can be mined, such as the investigation of alternative splicing and others, have created novel challenges for data management, exploration, analysis, and visualization. Although a large variety of RNA-Seq data analysis software packages has emerged, both open-source and commercial, most fail to simultaneously address the above challenges, while they lack obvious functionalities, such as estimating RNA abundance over non-annotated genomic regions of interest in real time. We have developed SeqCVIBE, an R Shiny web application for the interactive exploration, analysis, visualization, and genome browsing of large RNA-Seq datasets. SeqCVIBE allows for multiple on-the-fly visualizations and calculations, such as differential expression analysis, averaging genomic signals over specific regions of the genome, and calculating RNA abundances over custom, potentially non-annotated regions, such as novel long non-coding RNAs. In addition, SeqCVIBE comprises a database for pre-analyzed data, where users can navigate and explore results, as well as perform a variety of basic on-the-fly analyses and export the outcomes. Finally, we demonstrate the value of SeqCVIBE in the elucidation of the interplay of a novel lincRNA, WiNTRLINC1, and Wnt signaling in colon cancer.

Hyperforin and Myrtucommulone Derivatives Act as Natural Modulators of Wnt/β-Catenin Signaling in HCT116 Colon Cancer Cells

The therapeutic activities of natural plant extracts have been well known for centuries. Many of them, in addition to antiviral and antibiotic effects, turned out to have anti-tumor activities by targeting different signaling pathways. The canonical Wnt pathway represents a major tumorigenic pathway deregulated in numerous tumor entities, including colon cancer. Here, we investigated the acylphloroglucinols hyperforin (HF) from St. John’s wort (Hypericum perforatum L.) and myrtucommulone A (MC A) from myrtle (Myrtus communis) and semi-synthetic derivatives thereof (HM 177, HM 297, HM298) for their effects on Wnt/β-catenin signaling. None of these substances revealed major cytotoxicity on STF293 embryonic kidney and HCT116 colon carcinoma cells at concentrations up to 10 μM. At this concentration, HF and HM 177 showed the strongest effect on cell proliferation, whereas MC A and HM 177 most prominently inhibited anchorage-independent growth of HCT116 cells. Western blot analyses of active β-catenin and β-catenin/TCF reporter gene assays in STF293 cells revealed inhibitory activities of HF, MC A and HM 177. In line with this, the expression of endogenous Wnt target genes, Axin and Sp5, in HCT116 cells was significantly reduced. Our data suggest that the acylphloroglucinols hyperforin, myrtucommulone A and its derivative HM 177 represent potential new therapeutic agents to inhibit Wnt/β-catenin signaling in colon cancer.

Andean Berry (Vaccinium meridionale Swartz) Juice in Combination With Aspirin Modulated Apoptotic Signaling in Colon Cancer In Vitro and In Vivo

Abstract Objectives This research aimed to assess the impact of Andean Berry (Vaccinium meridionale Swartz) juice (ABJ) in combination with Aspirin in the apoptotic signaling in colon cancer in vitro and in vivo. We hypothesized that ABJ + Aspirin would produce the most effective anti-proliferative and pro-apoptotic effects in vitro and in vivo. Methods The polyphenolic composition of ABJ was carried out by HPLC-DAD. ABJ (0–30% v/v), Aspirin (0–20 mM), and their mixture were evaluated for their pro-apoptotic effects in human SW480 colorectal cancer cells, followed by human apoptosis proteomic and bioinformatic analysis and in silico docking potential between ABJ components and selected pro-apoptotic targets. For the in vivo assays, colorectal cancer was induced with two injections (separated 1 week each) of azoxymethane (AOM: 15 mg/kg body weight, BW), and treatments were evaluated for its chemopreventive and chemoprotective effects. Hence, 30 male and female Balb/c mice were randomly divided in 5 groups: negative control (basal diet, BD); and four AOM-induced groups: positive control (BD), Aspirin (25 mg/kg BW + BD), ABJ (30% v/v in drinking water ABJ + BD), and ABJ + Aspirin (30% v/v ABJ + 25 mg/kg BW Aspirin + BD). Macroscopic and histopathological parameters were evaluated in vivo. Results The mixture displayed the highest antiproliferative effects (+46%), arrested cell cycle at the G2/M phase, decreased cloning efficiency, but reduced Caspase 3/7 activity, suggesting an alternative apoptotic pathway, compared to untreated SW480 cells. Several pro-apoptotic (cytochrome C, TNFRSF1A, Bax, and Bad) and anti-apoptotic (Hsp70/Hsp32) proteins were decreased. ABJ flavonoids (rutin and kaempferol) exhibited the highest in silico affinity with proteins like TRAILR2 or Catalase. Both chemopreventive and chemoprotective approaches showed similar body/liver weight outcomes, but the mixture displayed the strongest aberrant crypt foci reduction in vivo. The chemopreventive approach was more effective in protecting the colon from AOM. Conclusions Results suggested the potential of ABJ to reduce Aspirin use in the alleviation of colorectal cancer markers in vitro and in vivo, modulating alternate pro-apoptotic signaling. Funding Sources The funding provided by COLCIENCIAS and DGAPA-CTIC-UNAM is appreciated.

Notch Signaling in Mammalian Intestinal Stem Cells: Determining Cell Fate and Maintaining Homeostasis.

The intestine serves mainly as a place for digestion and absorption and functions as an immune and endocrine organ. Intestinal stem cells (ISCs) play critical roles in the maintenance of intestinal homeostasis and regeneration, and a complex of signaling pathways is involved in these processes. The Notch signaling pathway is induced via distinct cell-to-cell connections, which are activated through the binding of the Notch ligand on the surface of niche cells to the Notch receptor on ISCs. Numerous studies have shown the central importance of Notch signaling in the proliferation and differentiation of ISCs. Here, we summarize the latest research progress on the crucial functions of Notch signaling in maintaining homeostasis and determining the cell fate of ISCs. Furthermore, the challenges of Notch signaling in colon cancer therapy strategies are also discussed. Several important questions regarding Notch regulation of ISCs are proposed.

Relationship between epithelial cell adhesion molecule and wingless/integrated-β-catenin signaling in colon cancer and the effect of XAV939 on the expression of related markers

Objective To investigate whether activation of Wingless/integrated-β-catenin (Wnt-β-catenin) pathway regulates epithelial cell adhesion molecule (EpCAM) expression in colon cancer and analyze the effect of XAV939 on colon cancer-associated markers. Methods After Wnt-β-catenin signaling was activated, relative expression levels of related genes were determined by quantitative real-time polymerase chain reaction (RT-qPCR). After constructing a mouse colon cancer model, XAV939 and/or 5-Fu were intraperitoneally injected for 1 week. Detection of related molecules expression in colon tissue by Western blotting. Results Compared with the control group, LiCl could significantly stimulate the expression of Wnt-β-catenin signaling pathway genes, and the levels of TACSTD1, DKK1, BAMBI, CCND1 and MYC genes were significantly increased by 1.20-, 2.44-, 4.34-, 2.57-, 1.58 fold (t=12.179, 20.661, 54.378, 19.384, 20.341, P<0.05), respectively. ZnCl2 treatment significantly inhibited the expression of TACSTD1 and CCND1 in HCT116 cells (tTACSTD1=36.467, 9.682, tCCND1=16.130, 17.003, P<0.05), which were down-regulated by about 50.06% and 34.38%, respectively. In the APC gene-deficient cells, the inhibitory effect of ZnCl2 on TACSTD1 and CCND1 was reversed. XAV939 and XAV939+ 5-fluorouracil (5-Fu) treatment significantly up-regulated the expression of Axin in HCT116 cells, which was about 15.97 and 17.2 fold higher than that of the control group (t=19.502, 18.236, P<0.05); and expression of β-catenin, EpCAM, telomerase reverse transcriptase (TERT) and bicorticosteroids and calmodulin dependent protein kinase-like 1 (DCAMKL-1) were down-regulated by 0.75 and 0.72 fold, 0.68 and 0.25 fold, 0.74 and 0.73 fold, 0.27 and 0.34 fold (tβ-catenin=20.412, 22.862, tEpCAM=26.336, 27.111, 82.711, tTERT=19.636, 22.787, 23.678, tDCAMKL-1=81.637, 64.814, P<0.05), respectively. Conclusion XAV939 inhibits tumor cell proliferation by blocking Wnt-β-catenin signaling down-regulation of β-catenin, target gene EpCAM and other related factors of CSC to promote colon cancer prognosis. Key words: Wingless/Integrated-β-catenin pathway; Epithelial cell adhesion molecule; XAV939; Colon cancer

Modulating PKCα Activity to Target Wnt/β-Catenin Signaling in Colon Cancer.

Inactivating mutations of the tumor suppressor Adenomatosis Polyposis Coli (APC), which are found in familial adenomatosis polyposis and in 80% of sporadic colorectal cancers (CRC), result in constitutive activation of the Wnt/β-catenin pathway and tumor development in the intestine. These mutations disconnect the Wnt/β-catenin pathway from its Wnt extracellular signal by inactivating the APC/GSK3-β/axin destruction complex of β-catenin. This results in sustained nuclear accumulation of β-catenin, followed by β-catenin-dependent co-transcriptional activation of Wnt/β-catenin target genes. Thus, mechanisms acting downstream of APC, such as those controlling β-catenin stability and/or co-transcriptional activity, are attractive targets for CRC treatment. Protein Kinase C-α (PKCα) phosphorylates the orphan receptor RORα that then inhibits β-catenin co-transcriptional activity. PKCα also phosphorylates β-catenin, leading to its degradation by the proteasome. Here, using both in vitro (DLD-1 cells) and in vivo (C57BL/6J mice) PKCα knock-in models, we investigated whether enhancing PKCα function could be beneficial in CRC treatment. We found that PKCα is infrequently mutated in CRC samples, and that inducing PKCα function is not deleterious for the normal intestinal epithelium. Conversely, di-terpene ester-induced PKCα activity triggers CRC cell death. Together, these data indicate that PKCα is a relevant drug target for CRC treatment.

Protein Tyrosine Phosphatase Receptor Type F Promotes Wnt Signaling in Colorectal Cancer

Colorectal cancer is the second leading cause of cancer deaths in the United States. A major mechanism behind the formation of colon cancer is the activation of Wnt signaling through a mutation in the APC or β‐catenin gene, which leads to accumulation of active β‐catenin. Aberrant signaling of the Wnt pathway has been linked to the initiation and progression of colorectal cancer. A major mechanism of control for the Wnt signaling pathway is protein phosphorylation. A fine balance between phosphorylation and dephosphorylation exist to keep the cell balanced depending on its needs. Protein phosphatases are important in regulating signaling pathways by dephosphorylating a large number of cellular substrates. In this study, we investigated the functional importance of PTPRF, a member of protein tyrosine phosphatase receptor type 2A, in regulating Wnt signaling in colon cancer. Bioinformatics analysis indicated that PTPRF is highly expressed in the intestinal epithelium. Silencing PTPRF in colon cancer cells resulted in a decrease in the expression of Wnt target genes. As a consequence, the rate of cell proliferation was significantly decreased in PTPRF knockdown cells. To determine the molecular mechanism, we examined the internalization process of Wnt‐Fzd‐LRP6 receptor complex, a key mode of regulation for the Wnt pathway. Specifically, we monitored the time course of LRP6‐GFP tracking in control and PTPRF knockdown cells upon Wnt stimulation. Our preliminary confocal microscopy results showed that the amount of LRP6‐GFP protein detected at the cell surface was decreased basally and the time course of LRP6‐GFP endocytosis was altered upon Wnt treatment in PTPRF knockdown cells. Interestingly, we found that PTPRF was co‐localized with LRP6‐GFP at both endocytic vesicles and plasma membrane in colon cancer cells, and Wnt treatment promoted internalization of PTPRF. Taken together, our study has identified PTPRF as a novel regulator of Wnt signaling by controlling the endocytosis of LRP6 receptor in colorectal cancer.Support or Funding InformationThis work was supported by R01CA133429 and R01CA208343.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

MiR-22 and miR-214 targeting BCL9L inhibit proliferation, metastasis, and epithelial-mesenchymal transition by down-regulating Wnt signaling in colon cancer.

The epithelial-mesenchymal transition (EMT) is crucial for cancer progression. Evidence has shown that miR-22 and miR-214 play a key role in colon cancer progression; however, the underlying mechanism remains to be known. The effects of miR-22 and miR-214 on EMT are contradictory in different cancers, and whether miR-22 and miR-214 are involved in the colon cancer EMT process needs to be elucidated. In this study, we evaluated the exact role and the regulation mechanism of miR-22 and miR-214 in colon cancer. After transfection with miR-22 expression vector, the cell proliferation and migration capacity of HCT116 and RKO cells were significantly suppressed. Also, E-cadherin was increased and vimentin was decreased by miR-22 overexpression. Similar effects were also observed after miR-214 expression vector transfection. Dual-luciferase reporter confirmed that BCL9L is the target gene of both miR-22 and miR-214. Silencing of BCL9L inhibits cell proliferation and migration, and the expression of E-cadherin and vimentin was also altered by BCL9L knockdown, which was consistent with miR-22 or miR-214 transfection. Furthermore, miR-22 and miR-214 inhibited tumor growth in nude mice. Moreover, although the association between BCL9L's lower expression and longer survival time was statistically nonsignificant, a trend existed; further studies in a larger cohort are needed. Collectively, these data suggest that miR-22 and miR-214 inhibit cell proliferation, migration, and EMT of colon cancer, most likely by targeting BCL9L.-Sun, R., Liu, Z., Han, L., Yang, Y., Wu, F., Jiang, Q., Zhang, H., Ma, R., Miao, J., He, K., Wang, X., Zhou, D., Huang, C. miR-22 and miR-214 targeting BCL9L inhibit proliferation, metastasis, and epithelial-mesenchymal transition by down-regulating Wnt signliang in colon cancer.

Contribution of drugs acting on the TLRs/MyD88 signaling pathway on colitis-associated cancer.

Toll-like receptors play a particularly significant role in colitis-associated cancer (CAC). MyD88 is the mediator in TLRs signal transduction process and it is indispensable for TLRs signaling except for TLR3. The conclusion of studies about the role of TLRs/MyD88 signaling in colon cancer remains contradictory: on one hand, TLRs/MyD88 signaling contributes to colon tumor cell proliferation, invasion and metastasis and inhibition of the expression of TLRs or MyD88 could prevent the growth of colon cancer cells; on the other hand, activation of the TLRs/MyD88 signaling pathway could inhibit the proliferation of colon cancer cells. This article is based on the expression levels of TLRs or MyD88 and the activation degrees of TLRs/MyD88 signaling pathway in different periods of colon cancer and, reviews the roles of TLRs/MyD88 signaling in the tumorigenesis and procession of CAC and the clinical application of agonists and inhibitor of TLRs or MyD88. This article is intended to explore the diverse roles of TLRs/MyD88 signaling pathway in CAC and to reveal the related molecular mechanism.

Highlights from Recent Cancer Literature

Highlights from Recent Cancer Literature

Abstract 5733: IL-11 as a therapeutic target to treat colorectal cancer

Abstract Introduction Colorectal cancer is a pressing health concern and there is a demand to develop novel therapeutics and improve current therapies to treat this disease. Immune checkpoint inhibitors (i.e. anti-PD-1 treatment) have been highly successful for the treatment of solid malignancies however, the majority of colorectal cancers do not typically respond to immunotherapy. Accumulating evidence alludes to a role for IL-11 signaling in tumor development although the mechanisms underlying IL-11 biology in colorectal cancer remain largely unknown. We postulate that IL-11 could be a mode of immunosuppression which can be targeted to overcome the poor responses of colorectal cancer to immunotherapy. Here we aim to investigate IL-11 signaling as a therapeutic strategy which can also be targeted in combination with anti-PD-1 treatment. Moreover, we present data that indicates an immunological function for IL-11 in modulating T cell anti-tumor activity. Method To assess the therapeutic potential for targeting IL-11 signaling in colon cancer in vivo, wild type and Il11r-/- C57BL/6 mice were injected subcutaneously in the flank on Day 0 with 1 x 106 MC38 colon cancer cells. The mice were then treated with an anti-PD-1 antibody i.p. dose once every 3 days. Mice were euthanised at Day 18. Harvested tumors were analysed by FACs and immunohistochemistry. To ascertain a role for IL-11 signaling in T cell activity, CD8+ and CD4+ T cells were FACs-sorted from wild type and il11r-/- mice, and activated with PMA/ionomycin for 24h. T cell activation was assessed by measuring mRNA levels of granzyme B and perforin by qPCR, and IFNγ production by ELISA. Results MC38 growth was attenuated in il11r-/- mice compared to wild type hosts. Lower tumor burden corresponded with a modest increase in tumor-infiltrating CD8+ T cells however we observed no differences in other immune cell subtypes (i.e. CD4+ T cells, MDSCs and macrophages). In addition, lower tumor burden corresponded with a marked reduction in Ki67 as assessed by immunohistochemistry. In addition, T cells harvested from il11r-/- hosts expressed lower levels of granzyme B, perforin and IFNγ under both basal conditions and following PMA/ionomycin stimulation. Conclusion Here we report that IL-11 signaling supports tumorigenesis using the MC38 colon cancer mouse model. For the first time, we have characterized a functional role for IL-11 in modulating T cell function. Overall, the findings from this study indicate IL-11R as a potential therapeutic target to improve the efficacy of immune checkpoint inhibitors for the treatment of colorectal cancer. Citation Format: Jennifer Huynh, Ashwini Chand, Matthias Ernst. IL-11 as a therapeutic target to treat colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5733.

Targeting tumor cell plasticity by combined inhibition of NOTCH and MAPK signaling in colon cancer.

In colorectal cancer, signaling pathways driving tumor progression are promising targets for systemic therapy. Besides WNT and MAPK signaling, activation of NOTCH signaling is found in most tumors. Here, we demonstrate that high NOTCH activity marks a distinct colon cancer cell subpopulation with low levels of WNT and MAPK activity and with a pronounced epithelial phenotype. Therapeutic targeting of MAPK signaling had limited effects on tumor growth and caused expansion of tumor cells with high NOTCH activity, whereas upon targeting NOTCH signaling, tumor cells with high MAPK activity prevailed. Lineage-tracing experiments indicated high plasticity between both tumor cell subpopulations as a mechanism for treatment resistance. Combined targeting of NOTCH and MAPK had superior therapeutic effects on colon cancer growth in vivo. These data demonstrate that tumor cells may evade systemic therapy through tumor cell plasticity and provide a new rationale for simultaneous targeting of different colon cancer cell subpopulations.

Apigenin induces apoptosis by suppressing Bcl-xl and Mcl-1 simultaneously via signal transducer and activator of transcription 3 signaling in colon cancer.

Apigenin is a natural flavonoid that exhibits anti-proliferative activity and induces apoptosis in various types of cancer, including colon cancer. The aim of the present study was to determine the mechanism underlying the apoptosis-inducing effect of apigenin in colon cancer. Apigenin reduced the proliferation of colon cancer cell lines, stimulated the cleavage of PARP and induced apoptosis in a dose-dependent manner. Apigenin treatment also suppressed the expression of the anti-apoptotic proteins Bcl-xL and Mcl-1. Small interfering RNA was used to knockdown Bcl-xL and Mcl-1 expression alone and in concert, and the proliferation and apoptosis of cancer cells were subsequently measured. The knockdown of Bcl-xL and Mcl-1 expression together markedly suppressed cell proliferation and induced apoptosis. Apigenin treatment also inhibited the phosphorylation of signal transducer and activator of transcription3 (STAT3), which targets Bcl-xL and Mcl-1. The results of the current study therefore determined that apigenin induces the apoptosis of colon cancer cells by inhibiting the phosphorylation of STAT3 and consequently downregulates the anti-apoptotic proteins Bcl-xL and Mcl-1.