Therapeutic Agent For Colon Cancer Research Articles

Cinobufotalin regulates the USP36/c-Myc axis to suppress malignant phenotypes of colon cancer cells in vitro and in vivo.

Ubiquitin-specific protease 36 (USP36) has been reported to exhibit oncogenic effects in various malignancies, but the function of USP36 in colon cancer progression remains indefinite. Herein, we aimed to determine the role and mechanism of USP36 in malignant phenotypes of colon cancer cells and explore the potential drug targeting USP36. Bioinformatics analyses indicated that USP36 is highly expressed and significantly related to tumor stages in colon cancer. Besides, USP36 was further up-regulated in oxaliplatin (Oxa)-resistant colon cancer cells. Colony formation, Edu staining, Transwell, wound healing, sphere formation, and CCK-8 assays were conducted and showed that the proliferation, Oxa-resistance, migration, stemness, and invasion of HCT116 cells were promoted after overexpressing USP36, while suppressed by USP36 knockdown. Mechanically, USP36 enhances c-Myc protein stabilization in HCT116 cells via deubiquitination. AutoDock tool and ubiquitin-AMC hydrolysis assay identified cinobufotalin (CBF), an anti-tumor drug, maybe a USP36 inhibitor by inhibiting its deubiquitination activity. CBF significantly prohibited proliferation, migration, invasion, and stemness of HCT116 cells and reversed Oxa-resistance, whereas enforced expression of USP36 blocked these effects. Moreover, in vivo analyses confirmed the oncogenic role of USP36 and the therapeutic potential of CBF in the malignancy of colon cancer. In conclusion, CBF may be a promising therapeutic agent for colon cancer due to its regulation of the USP36/c-Myc axis.

Abstract 483: Hederacolchiside A1 inhibits autophagy via CTSC inhibition and inhibits growth in colon cancer

Abstract Background: Autophagy is a normal regulatory process that degrades non-functional or unnecessary cellular components. The degradation of components provides materials for the synthesis of cellular components and, during tumor development, may provide energy. Therefore, autophagy regulation may have potential therapeutic uses in oncology. The triterpenoid saponin hederacolchiside A1 (HA1) has potent antitumor effects; however, its role in autophagy is still unknown. Methods: In the present study, we used human colon cancer cells (SW480 and HT29) and mouse colon cancer cells (CT26) for the main experiments, and several additional cancer cell lines for other experiments. To assess the autophagy dysregulation caused by HA1, we evaluated the protein expressions of two autophagy markers (LC3 and SQSTM1) using Western blotting and the changes in organelles using LC3 puncta assay and transmission electron microscopy. We compared the effects of HA1 and other autophagy inhibitors. Additionally, we compared the HA1-induced decrease in cathepsin C (CTSC) expression in tumors and non-tumors using publicly available data. The effect of HA1 on tumor growth was evaluated in vitro using a three-dimensional spheroid model and patient-derived colon organoids, and in vivo based on tumor growth in a subcutaneous injection mouse model. Results: HA1 treatment resulted in marked vacuolization of colon and other cancer cells. Additionally, autophagy was induced by the accumulation of LC3-II and SQSTM1. These findings were supported by increased LC3 puncta and abnormal organelle morphology. Compared to treatment with other autophagy inhibitors, HA1 treatment resulted in the formation of distinct vacuoles and increased LC3 and SQSTM1, similar to chloroquine treatment. The publicly available data showed that the lysosomal protease CTSC was increased in several cancers, including colon cancer, compared to the normal tissues. Furthermore, HA1 decreased the CTSC expression and enzymatic activity independently of the proteasome degradation, resulting in autophagy dysregulation and, subsequently, autophagy flux inhibition. HA1 inhibited cell growth and induced cell cycle arrest in the two-dimensional culture, three-dimensional spheroids, patient-derived colon cancer organoids, and the in vivo experiments. Conclusion: HA1 inhibits cell growth and induces autophagy dysregulation. Therefore, HA1 may be a potential therapeutic agent in colon cancer. Citation Format: Solbi Kim, Eunji Kim, Minju Han, Youn Seo Oh, Sora Kang, Heung Jin Jeon, Hyo Jin Lee. Hederacolchiside A1 inhibits autophagy via CTSC inhibition and inhibits growth in colon cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 483.

Apoptosis of colon cancer CT-26 cells induced polysaccharide from Cyclocarya paliurus and its phosphorylated derivative via intrinsic mitochondrial passway

In this study, the antitumor properties and the possible molecular mechanisms of Cyclocarya paliurus polysaccharide (CP) and its phosphorylated derivative (P-CP) on CT-26 mouse colon carcinoma cells were investigated. Results found that CP had high inhibition ratio against CT-26 cells. The flow cytometry results found that CP treatment could cause the intracellular acidification, arrest the cell cycle in the S phase and increase reactive oxygen species generation. Additionally, CP treatment triggered mitochondrial membrane potential depolarization and Ca2+ overloading, and broke down the balance of antioxidant system, Na+/K+-ATPase and Ca2+-ATPase. Further analysis found CP induced cell apoptosis through improving the activities of caspase-3 and caspase-9, and increasing the level of cytochrome C. Furthermore, the comparative study of antitumor effect on CT-26 cells displayed that the phosphorylation enhanced antitumor activities of polysaccharides. These results suggest CP is a potential natural therapeutic agent for colon cancer and phosphorylation represents an effective method of enhancing the antitumor activity of CP.

Hederacolchiside A1 Suppresses Autophagy by Inhibiting Cathepsin C and Reduces the Growth of Colon Cancer.

While autophagy degrades non-functional or unnecessary cellular components, producing materials for synthesizing cellular components, it can also provide energy for tumor development. Hederacolchiside A1 (HA1) derived from anemone raddeana has anticancer effects on several carcinomas by inducing apoptosis or exhibiting cytotoxicity, but the relationship with autophagy has not been studied. We investigated the association between HA1 and autophagy and evaluated its anticancer effect on colon cancer. HA1 induced accumulation of the autophagy-related markers LC3B and SQSTM1, with distinct vacuolar formation, unlike other autophagy inhibitors; the effects were similar to those of chloroquine. In addition, HA1 decreased the expression and proteolytic activity of lysosomal protein cathepsin C, reduced the growth of colon cancer cells in vitro, and inhibited tumor growth in vivo. It also reduced the expression of Ki-67 and cathepsin C in mouse tissues and reduced the growth of spheroids and organoids composed of cancer cells. Taken together, these results imply that HA1 regulates cell growth and autophagy and has potential as a promising therapeutic agent in colon cancer.

Targeting BAP1 with small compound inhibitor for colon cancer treatment

BRCA1-associated protein-1 (BAP1) is a ubiquitin C-terminal hydrolase domain-containing deubiquitinase. The gene encoding BAP1 is mutated in various human cancers, including mesothelioma, uveal melanoma and renal cell carcinoma. BAP1 plays roles in many cancer-related cellular functions, including cell proliferation, cell death, and nuclear processes crucial for genome stability, such as DNA repair and replication. While these findings suggest that BAP1 functions as a tumor suppressor, recent data also suggest that BAP1 might play tumor-promoting roles in certain cancers, such as breast cancer and hematopoietic malignancies. Here, we show that BAP1 is upregulated in colon cancer cells and tissues and that BAP1 depletion reduces colon cancer cell proliferation and tumor growth. BAP1 contributes to colon cancer cell proliferation by accelerating DNA replication and suppressing replication stress and concomitant apoptosis. A recently identified BAP1 inhibitor, TG2-179-1, which seems to covalently bind to the active site of BAP1, exhibits potent cytotoxic activity against colon cancer cells, with half-maximal inhibitory concentrations of less than 10 μM, and inhibits colon tumor growth. TG2-179-1 exerts cytotoxic activity by targeting BAP1, leading to defective replication and increased apoptosis. This work therefore shows that BAP1 acts oncogenically in colon cancer and is a potential therapeutic target for this cancer. Our work also suggests that TG2-179-1 can be developed as a potential therapeutic agent for colon cancer.

Polyphyllin I Promotes Autophagic Cell Death and Apoptosis of Colon Cancer Cells via the ROS-Inhibited AKT/mTOR Pathway

Colon cancer is a common malignant tumor of the digestive tract, and it is considered among the biggest killers. Scientific and reasonable treatments can effectively improve the survival rate of patients if performed in the early stages. Polyphyllin I (PPI), a pennogenyl saponin isolated from Paris polyphylla var. yunnanensis, has exhibited strong anti-cancer activities in previous studies. Here, we report that PPI exhibits a cytotoxic effect on colon cancer cells. PPI suppressed cell viability and induced autophagic cell death in SW480 cells after 12 and 24 h, with the IC50 values 4.9 ± 0.1 μmol/L and 3.5 ± 0.2 μmol/L, respectively. Furthermore, we found PPI induced time-concentration-dependent autophagy and apoptosis in SW480 cells. In addition, down-regulated AKT/mTOR activity was found in PPI-treated SW480 cells. Increased levels of ROS might link to autophagy and apoptosis because reducing the level of ROS by antioxidant N-acetylcysteine (NAC) treatment mitigated PPI-induced autophagy and apoptosis. Although we did not know the molecular mechanism of how PPI induced ROS production, this is the first study to show that PPI induces ROS production and down-regulates the AKT/mTOR pathway, which subsequently promotes the autophagic cell death and apoptosis of colon cancer cells. This present study reports PPI as a potential therapeutic agent for colon cancer and reveals its underlying mechanisms of action.

β-carotene regulates cancer stemness in colon cancer in vivo and in vitro.

BACKGROUND/OBJECTIVESColorectal cancer (CRC) is the third most common cancer worldwide and has a high recurrence rate, which is associated with cancer stem cells (CSCs). β-carotene (BC) possesses antioxidant activity and several anticancer mechanisms. However, no investigation has examined its effect on colon cancer stemness.MATERIALS/METHODSCD133+CD44+ HCT116 and CD133+CD44+ HT-29 cells were isolated and analyzed their self-renewal capacity by clonogenic and sphere formation assays. Expressions of several CSCs markers and Wnt/β-catenin signaling were examined. In addition, CD133+CD44+ HCT116 cells were subcutaneously injected in xenograft mice and analyzed the effect of BC on tumor formation, tumor volume, and CSCs markers in tumors.RESULTSBC inhibited self-renewal capacity and CSC markers, including CD44, CD133, ALDH1A1, NOTCH1, Sox2, and β-catenin in vitro. The effects of BC on CSC markers were confirmed in primary cells isolated from human CRC tumors. BC supplementation decreased the number and size of tumors and delayed the tumor-onset time in xenograft mice injected with CD133+CD44+ HCT116 cells. The inhibitory effect of BC on CSC markers and the Wnt/β-catenin signaling pathway in tumors was confirmed in vivo as well.CONCLUSIONSThese results suggest that BC may be a potential therapeutic agent for colon cancer by targeting colon CSCs.

Isolation and anticancer effect of brucine in human colon adenocarcinoma cells HT-29

Context: Brucine is broadly used in the treatment of numerous types of tumors, and the application of brucine to colon cancer is stated. However, HT-29 cells have established comparatively little consideration, and the mechanism underlying the antitumor activity leftovers largely unknown. Objectives: The objective of the study is to isolate and examine the effect of brucine on human colon adenocarcinoma cell line HT-29. Materials and Methods: Crude brucine was acquired by the extraction of Nux vomica with 80% EtOH. Diatomite chromatography and semipreparative high-performance liquid chromatography were used to obtain brucine in pure form. HT-29 cells were treated with brucine (125, 250, and 500 μM) for 24–72 h. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to assess the cell proliferation. Annexin V-FITC/propidium iodide (PI) staining was used to identify the activity of apoptotic. Flow cytometry was used to scrutinize the effect of brucine on cell cycle progression and mitochondrial membrane potential (MMP). Bcl-2, p53, caspase-3, PARP, and caspase-9 were spotted by Western blotting test. Results: Brucine reduced cell viability with an IC50 value of 0.368, 0.226, and 0.168 μmol/L at 24, 48, and 72 h, respectively. The apoptosis of HT-29 was persuaded by 33.06%, 44.47%, and 71.96% at 125, 250, and 1000 μmol/L of brucine, respectively. Brucine at 250 μmol/L led to cell cycle arrest in the G1/S/G2 phase and inhibited the HT-29 cells in the G1 phase. H1-UL/H1-UR was determined to be 1.79, 1.26, and 0.54 at 125, 250, and 1000 μmol/L, respectively. Brucine at 125, 250, and 1000 μmol/L downregulated the expression of Bcl-2 but augmented the expression of p53, caspase-3, PARP, and caspase-9. Conclusion: The outcomes displayed that brucine could prevent cell proliferation, arrest the cell cycle, and increase the loss of MMP in the HT-29 cell line. Furthermore, brucine could also persuade cell apoptosis through the expression of proapoptotic and apoptotic proteins comprising p53, caspase-3, caspase-9, and PARP. To sum up, our preclinical data designated that brucine was a probable therapeutic agent for colon cancer.

Cordyceps sinensis polysaccharide inhibits colon cancer cells growth by inducing apoptosis and autophagy flux blockage via mTOR signaling

Cordyceps sinensis is thought to have anti-cancer effects, but its mechanisms remain elusive. In this study, we aimed to investigate the anti-cancer effect of Cordyceps sinensis polysaccharide (CSP) on human colon cancer cell line (HCT116) and its mechanism. Results indicated that CSP significantly inhibited the proliferation of HCT116 cells, increased autophagy and apoptosis, while blocked autophagy flux and lysosome formation. Further experiments showed that CSP decreased the expression of PI3K and phosphorylation level of AKT and mTOR, increased the expression of AMPKa and phosphorylation level of ULK1. In addition, repression of CSP-induced autophagy by bafilomycin (autophagy inhibitor) enhanced apoptosis and cell death of HCT116 cells. Hence, our findings suggested that CSP inhibited the proliferation of HCT116 cells by inducing apoptosis and autophagy flux blockage, which might be achieved through PI3K-AKT-mTOR and AMPK-mTOR-ULK1 signaling. CSP may be a potential therapeutic agent for colon cancer.

The bacterial instrument as a promising therapy for colon cancer.

Colon cancer is a great health concern worldwide, as it is the second leading cause of cancer-related death. Conventional treatment of cancer such as surgery, radiotherapy, and chemotherapy are faced with limitations and side effects. Therefore, strategies for the treatment of cancer need to be modified or new strategies replacing the old one. The aim of this study is to review the role of bacteria or their products (such as peptides, bacteriocins, and toxins) as a therapeutic agent for colon cancer. Recently, the therapeutic role of bacteria and their products in colon cancer treatment holds promise as emerging novel anti-cancer agents. Unlike the conventional treatments, targeted therapy based on the use of bacteria that are able to directly target tumor cells without affecting normal cells is evolving as an alternative strategy. Moreover, several bacterial species were used in live, attenuated or genetically modified that are able to multiply selectively in tumors and inhibiting their growth.

Tributyltin(IV) ferulate, a novel synthetic ferulic acid derivative, induces autophagic cell death in colon cancer cells: From chemical synthesis to biochemical effects

Ferulic acid (FA) is a natural phenolic phytochemical that has low toxicity and exhibits therapeutic effects against various diseases, behaving as an antioxidant. FA also displays modest antitumor properties that have been reported at relatively high concentrations. With the aim of improving the anti-tumor efficacy of FA, we synthesized the novel compound tributyltin(IV) ferulate (TBT-F). The coordination environment at the tin center was investigated spectroscopically. Following synthesis, chemical characterization and computational analysis, we evaluated TBT-F effects in colon cancer cells. The results showed that TBT-F, at nanomolar range concentrations, was capable of reducing the viability of HCT116, HT-29 and Caco-2 colon cancer cells. On the other hand, FA was completely inefficacious at the same treatment conditions. Cell viability reduction induced by TBT-F was associated with G2/M cell cycle arrest, increase in membrane permeabilization and appearance of typical morphological signs. TBT-F-induced cell death seemed not to involve apoptotic or necroptotic markers whereas autophagic vacuoles appearance and increase in LC3-II and p62 autophagic proteins were observed after treatment with the compound. The autophagy inhibitor bafylomicin A1 markedly prevented the effect of TBT-F on colon cancer cells, thus indicating that autophagy is triggered as a cell death process.Taken together, our results strongly suggest that the novel ferulic derivative TBT-F is a promising therapeutic agent for colon cancer since it is capable of triggering autophagic (type-II) cell death that may be important in case of resistance to classic apoptosis.

Targeting transcription factor TCF4 by γ-Mangostin, a natural xanthone.

Given that colon cancer is the third most common cancer in incidence and cause of death in the United States, and current treatment modalities are insufficient, there is a need to develop novel agents. Towards this, here we focus on γ-Mangostin, a bioactive compound present in the Mangosteen (Garcinia mangostana) fruit. γ-Mangostin suppressed proliferation and colony formation, and induced cell cycle arrest and apoptosis of colon cancer cell lines. Further, γ-Mangostin inhibited colonosphere formation. Molecular docking and CETSA (Cellular thermal shift assay) binding assays demonstrated that γ-Mangostin interacts with transcription factor TCF4 (T-Cell Factor 4) at the β-catenin binding domain with the binding energy of -5.5 Kcal/mol. Moreover, γ-Mangostin treatment decreased TCF4 expression and reduced TCF reporter activity. The compound also suppressed the expression of Wnt signaling target proteins cyclin D1 and c-Myc, and stem cell markers such as LGR5, DCLK1 and CD44. To determine the effect of γ-Mangostin on tumor growth in vivo, we administered nude mice harboring HCT116 tumor xenografts with 5 mg/Kg of γ-Mangostin intraperitoneally for 21 days. γ-Mangostin treatment significantly suppressed tumor growth, with notably lowered tumor volume and weight. In addition, western blot analysis revealed a significant decrease in the expression of TCF4 and its downstream targets such as cyclin D1 and c-Myc. Together, these data suggest that γ-Mangostin inhibits colon cancer growth through targeting TCF4. γ-Mangostin may be a potential therapeutic agent for colon cancer.

Nanoceria: A rare-earth nanoparticle as a promising anti-cancer therapeutic agent in colon cancer

The bioactivity and physical characteristics of CeO2 nanoparticles are significantly dependent on the type of the particle, particle size and defects. Herein, a facile and cost effective microwave-assisted combustion route was used to prepare pure CeO2 nanoparticles (NPs). The samples were thoroughly characterized by various techniques and tested as anti-cancer therapeutic agent in colon cancer. The structural investigations (X-ray Powder Diffraction) revealed the formation of single phase cubic fluorite-type structure of CeO2 with Fm-3m space group. Morphological analysis (FESEM), demonstrated the aggregation of irregular nanoparticles with grain size ~ 20–40 nm. To have more knowledge on the sample morphology, TEM and HRTEM images were taken. TEM image showed ceria NPs with squared shape and particle size in 50–95 nm range. Furthermore, HR-TEM micrographs confirmed the crystallinity of the CeO2 sample, which was explored by calculating the distance between the fringes in the corresponding Fourier transformed images. The BET specific surface area (SSA) of as-synthesized ceria nanoparticles, was observed to be 25 m2/g. UV–vis spectral analysis reveals that the direct band gap of CeO2 nanoparticles is about 2.8 eV.It was interesting to observe that, the as prepared NPs exhibit remarkable differential cytotoxicity towards healthy (BHK121, Baby Hamster Kidney cells) and human Colon cancer cells (HCT116). Nuclear fragmentation assay indicated clear DNA fragmentation in HCT116 cells, whereas intact nucleus was observed in normal cells, suggesting ceria induced apoptotic cell death in colon cancer cells. In sum, MACS generated ceria nanoparticles could uncover a new avenue in cancer therapy.

Acid-responsive nanoparticles as a novel oxidative stress-inducing anticancer therapeutic agent for colon cancer.

ObjectiveNanoparticles can efficiently carry and deliver anticancer agents to tumor sites. Mounting evidence indicates that many types of cancer cells, including colon cancer, have a weakly acidic microenvironment and increased levels of reactive oxygen species. The construction of nano drug delivery vehicles “activatable” in response to the tumor microenvironment is a new antitumor therapeutic strategy.MethodsCinnamaldehyde (CA) was designed to link directly with dextran to form a polymer through an acid cleavable acetal bond. Herein, a novel pH-sensitive drug delivery system was constructed with co-encapsulated 10-hydroxy camptothecin (HCPT). Dynamic light scattering (DLS) analysis, transmission electron microscopy (TEM) analysis, and release kinetics analysis of HCPT-CA-loaded nanoparticles (PCH) were conducted to investigate the physical and chemical properties. The cellular uptake signatures of the nanoparticles were observed by confocal microscopy and flow cytometry. Cell viability, cell scratch assay, apoptosis assay, and colony formation assay were performed to examine the potent antiproliferative and apoptotic effects of the PCH. The antitumor mechanism of the treatment with PCH was evaluated by Western blotting, flow cytometry, and TEM analysis. The pharmacokinetics of PCH were examined in healthy Sprague Dawley rats within 6 hours after sublingual vein injection. We lastly examined the biodistribution and the in vivo anticancer activity of PCH using the xenograft mouse models of HCT116 cells.ResultsBoth HCPT and CA were quickly released by PCH in an acidic microenvironment. PCH not only induced cancer cell death through the generation of intracellular reactive oxygen species in vitro but also facilitated the drug uptake, effectively prolonged drug circulation, and increased accumulation of drug in tumor sites. More attractively, PCH exhibited excellent therapeutic performance and better in vivo systemic safety.ConclusionOverall, PCH not only utilized the tumor microenvironment to control drug release, improve drug pharmacokinetics, and passively target the drug to the tumor tissue, but also exerted a synergistic anticancer effect. The acid-responsive PCH has enormous potential as a novel anticancer therapeutic strategy.

Inhibition of cell cycle progression by the hydroxytyrosol-cetuximab combination yields enhanced chemotherapeutic efficacy in colon cancer cells.

Hydroxytyrosol (HT), a polyphenol of olive oil, downregulates epidermal growth factor (EGFR) expression and inhibits cell proliferation in colon cancer (CC) cells, with mechanisms similar to that activated by the EGFR inhibitor, cetuximab. Here, we studied whether HT treatment would enhance the cetuximab inhibitory effects on cell growth in CC cells.HT-cetuximab combination showed greater efficacy in reducing cell growth in HT-29 and WiDr cells at concentrations 10 times lower than when used as single agents. This reduction was clearly linked to cell cycle blockade, occurring at G2/M phase. The cell cycle arrest in response to combination treatment is related to cyclins B, D1, and E, and cyclin-dependent kinase (CDK) 2, CDK4, and CDK6 down-regulation, and to the concomitant over-expression of CDK inhibitors p21 and p27. HT and cetuximab stimulated a caspase-independent cell death cascade, promotedtranslocation of apoptosis-inducing factor (AIF) from mitochondria to nucleus and activated the autophagy process.Notably, normal colon cells and keratinocytes were less susceptible to combo-induced cell death and EGFR downregulation.These results suggest a potential role of diet, containing olive oil, during cetuximab chemotherapy of colon tumor. HT may be a competent therapeutic agent in CC enhancing the effects of EGFR inhibitors.

Abstract 5175: γ-Mangostin, a natural xanthone derivative targets Wnt signaling pathway in colon cancer cells

Abstract Background: Colorectal cancer is the third most common cancer in incidence and cause of death in the United States. The current treatment modalities include chemotherapy, radiation, and surgery. Many people are genetically predisposed for colon cancer through mutations in genes such as adenomatous polyposis coli (APC). While the absence of APC causes aberrant Wnt/Beta catenin signaling, the APC mutations are found in more than 80% of colorectal tumors. γ-Mangostin is a major bioactive compound present in Mangosteen (Garcinia mangostana) which possess significant anti-cancer activity. Herein, we investigated the effects of γ -Mangostin on colon cancer growth and elucidated its mechanistic action through Wnt signaling pathway. Methods: HCT116, SW480 and RKO cell lines were used in the study. The effects of γ-Mangostin on cell proliferation were assessed by hexosaminidase and clonogenicity assays. Effects of γ-Mangostin on apoptosis were evaluated by cell cycle and western blot analysis. Moreover the effect of γ-Mangostin on colonosphere formation was also evaluated. Furthermore, the effect of γ-Mangostin on Wnt signaling proteins was evaluated by western blot analysis. The in vivo anti-cancer effect of γ -Mangostin was investigated on the HCT116 subcutaneous tumor xenograft model implanted in five-week-old male athymic nude mice. Further, the effect of γ -Mangostin was assessed by the specific marker expression in tissue samples by western blot analysis and immunohistochemistry. Results: γ-Mangostin treatment resulted in a dose and time dependent inhibition of proliferation and colony formation in all the three cell lines. Treatment also induced colon cancer cells to undergo G0/G1 and S-phase arrest. Apoptosis was confirmed by increased levels of Bax/Bcl2 ratio, coupled with a reduction in cyclin D1. γ -Mangostin significantly reduced the number and size of colonospheres. Moreover, γ-Mangostin treatment decreased the expression of Wnt signaling proteins, which suggest that γ-Mangostin inhibits the colon cancer growth through Wnt signaling pathway. To determine the effect of γ-Mangostin on tumor growth in vivo, nude mice harboring HCT116 tumor xenografts in their flanks were administered with 5mg/Kg γ-Mangostin intraperitoneally for 21 days. γ-Mangostin treatment significantly reduced the tumor growth, with notably lower tumor volume and weight. Western blot and immunohistochemistry analyses revealed significant decrease in the expression of Wnt signaling proteins. Conclusion: Together, these data suggest that γ-Mangostin inhibits colon cancer growth through Wnt signaling pathway. γ-Mangostin may be a potential therapeutic agent for colon cancer. Citation Format: Balaji Krishnamachary, Dharmalingam Subramaniam, Thomas Attard, Seth Septer, Shrikant Anant. γ-Mangostin, a natural xanthone derivative targets Wnt signaling pathway in colon cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5175. doi:10.1158/1538-7445.AM2017-5175

The soy-derived peptide Vglycin inhibits the growth of colon cancer cells invitro and invivo.

Vglycin, a novel natural polypeptide isolated from pea seeds, possesses antidiabetic properties. Our previous studies have shown that Vglycin can induce the differentiation of human colon adenocarcinoma cells. We aimed to determine the anticancer activity of Vglycin against colon cancer cells and to elucidate related apoptosis-inducing mechanisms. Treatment with purified Vglycin significantly reduced growth, viability, and colony formation of CT-26, SW480, and NCL-H716 colon cancer cells in a dose-dependent manner while down-regulating the expression of proliferating cell nuclear antigen. Mouse xenograft studies showed a 38% inhibition of colon cancer growth in mice treated with Vglycin (20 mg/kg/day) at day 21. Furthermore, the potential mechanisms involved in Vglycin-induced cell apoptosis were examined using cell cycle studies, ultrastructural examination, as well as apoptosis-associated pathway analysis. The results showed that Vglycin significantly promoted apoptosis and G1/S phase cell cycle arrest. As revealed by Western blot, the expression of CDK2 and Cyclin D1 was down-regulated in all three Vglycin-treated colon cancer cells, indicating that the CDK2/Cyclin D1 cell cycle pathway involved in the initiation and progression of colon cancer. Moreover, the inhibition of Vglycin-induced cell proliferation in colon cancer cells was accompanied by alteration of the expression levels of the apoptosis-related proteins Bax, Bcl-2 and Mcl-1, and an increase of caspase-3 activity. Together, our results suggest that Vglycin may be another plant-derived peptide that suppresses colon cancer, supporting the continued investigation of Vglycin as therapeutic agent for colon cancer. Impact statement The antidiabetic properties and the capability of inducing differentiation of human colon adenocarcinoma cells of Vglycin have been reported in our previous studies. However, the anticancer potential of Vglycin on colon cancer cells and its possible related mechanisms were still unknown. In this study, we found that Vglycin could reduce growth, viability, and colony formation or colony size of CT-26, SW480, and NCL-H716 colon cancer cells. Moreover, Vglycin decreased tumor volume by 38% in xenograft mice transplanted with CT-26 cells. The mechanisms of these phenomena may be due to the down-regulated CDK2 and Cyclin D1, G1/S phase cell cycle arrest, and the dysregulated expression of Bax, Bcl-2, and Mcl-1. The findings highlight the anticancer potential of Vglycin against colon cancer cells, and suggest Vglycin may be another colon cancer potential suppressive component of plant-derived peptides.

Pharmacological blockade of aquaporin-1 water channel by AqB013 restricts migration and invasiveness of colon cancer cells and prevents endothelial tube formation in vitro.

BackgroundAquaporins (AQP) are water channel proteins that enable fluid fluxes across cell membranes, important for homeostasis of the tissue environment and for cell migration. AQP1 knockout mouse models of human cancers showed marked inhibition of tumor-induced angiogenesis, and in pre-clinical studies of colon adenocarcinomas, forced over-expression of AQP1 was shown to increase angiogenesis, invasion and metastasis. We have synthesized small molecule antagonists of AQP1. Our hypothesis is that inhibition of AQP1 will reduce migration and invasiveness of colon cancer cells, and the migration and tube-forming capacity of endothelial cells in vitro.MethodsExpression of AQP1 in cell lines was assessed by quantitative (q) PCR, western blot and immunofluorescence, while expression of AQP1 in human colon tumour tissue was assessed by immunohistochemistry. The effect of varying concentrations of the AQP1 inhibitor AqB013 was tested on human colon cancer cell lines expressing high versus low levels of AQP1, using wound closure (migration) assays, matrigel invasion assays, and proliferation assays. The effect of AqB013 on angiogenesis was tested using an endothelial cell tube-formation assay.ResultsHT29 colon cancer cells with high AQP1 levels showed significant inhibition of migration compared to vehicle control of 27.9 % ± 2.6 % (p < 0.0001) and 41.2 % ± 2.7 (p <0.0001) treated with 160 or 320 μM AqB013 respectively, whereas there was no effect on migration of HCT-116 cells with low AQP1 expression. In an invasion assay, HT29 cells treated with 160 μM of AqB013, showed a 60.3 % ± 8.5 % decrease in invasion at 144 hours (p < 0.0001) and significantly decreased rate of invasion compared with the vehicle control (F-test, p = 0.001). Almost complete inhibition of endothelial tube formation (angiogenesis assay) was achieved at 80 μM AqB013 compared to vehicle control (p < 0.0001).ConclusionThese data provide good evidence for further testing of the inhibitor as a therapeutic agent in colon cancer.Electronic supplementary materialThe online version of this article (doi:10.1186/s13046-016-0310-6) contains supplementary material, which is available to authorized users.

Antioxidant and Anticancer Properties of the Extracts from Lepisorus thunbergianus (Kaulf.) Ching

Lepisorus thunbergianus (Kaulf.) Ching has been used in folk medicine in Korea. In this study, a L. thunbergianus methanol extract and its fractions were investigated for their antioxidant properties. The results showed that the ethyl acetate and butanol fractions of L. thunbergianus possess potent DPPH radical scavenging activities. Both fractions also possessed reducing power and inhibited reactive oxygen species formation. In addition, the cytotoxic activity of the L. thunbergianus n-hexane fraction (HF) was investigated. The results suggested that the HF remarkably suppressed proliferation of human breast, liver and colon cancer cells. These results demonstrate, for the first time, that L. thunbergianus extract induces apoptosis in SW620 cells, suggesting that L. thunbergianus may have potential as a therapeutic agent for colon cancer.

Antitumor Effects of Fucoidan on Human Colon Cancer Cells via Activation of Akt Signaling.

We identified a novel Akt signaling mechanism that mediates fucoidan-induced suppression of human colon cancer cell (HT29) proliferation and anticancer effects. Fucoidan treatment significantly inhibited growth, induced G1-phase-associated upregulation of p21WAF1 expression, and suppressed cyclin and cyclin-dependent kinase expression in HT29 colon cancer cells. Additionally, fucoidan treatment activated the Akt signaling pathway, which was inhibited by treatment with an Akt inhibitor. The inhibition of Akt activation reversed the fucoidan-induced decrease in cell proliferation, the induction of G1-phase-associated p21WAF1 expression, and the reduction in cell cycle regulatory protein expression. Intraperitoneal injection of fucoidan reduced tumor volume; this enhanced antitumor efficacy was associated with induction of apoptosis and decreased angiogenesis. These data suggest that the activation of Akt signaling is involved in the growth inhibition of colon cancer cells treated with fucoidan. Thus, fucoidan may serve as a potential therapeutic agent for colon cancer.