Apoptosis In Colon Cancer Cells Research Articles

Pro-apoptotic effect of haem oxygenase-1 in human colorectal carcinoma cells via endoplasmic reticular stress.

Several biological effects of haem oxygenase (HO)‐1, including anti‐inflammatory, antiapoptotic and antioxidative properties were reported; however, the role of HO‐1 in apoptosis is still unclear. In the presence of stimulation by cobalt protoporphyrin (CoPP), an HO‐1 inducer, apoptotic characteristics were observed, including DNA laddering, hypodiploid cells, and cleavages of caspase (Casp)‐3 and poly(ADP) ribose polymerase (PARP) proteins in human colon carcinoma COLO205, HCT‐15, LOVO and HT‐29 cells in serum‐free (SF) conditions with increased HO‐1, but not heat shock protein 70 (HSP70) or HSP90. The addition of 10% foetal bovine serum (FBS) or 1% bovine serum albumin accordingly inhibited CoPP‐induced apoptosis and HO‐1 protein expression in human colon cancer cells. CoPP‐induced apoptosis of colon cancer cells was prevented by the addition of the pan‐caspase inhibitor, Z‐VAD‐FMK (VAD), and the Casp‐3 inhibitor, Z‐DEVD‐FMK (DEVD). N‐Acetyl cysteine inhibited reactive oxygen species‐generated H2O2‐induced cell death with reduced intracellular peroxide production, but did not affect CoPP‐induced apoptosis in human colorectal carcinoma (CRC) cells. Two CoPP analogs, ferric protoporphyrin and tin protoporphyrin, did not affect the viability of human CRC cells or HO‐1 expression by those cells, and knockdown of HO‐1 protein expression by HO‐1 small interfering (si)RNA reversed the cytotoxic effect elicited by CoPP. Furthermore, the carbon monoxide (CO) donor, CORM, but not FeSO4 or biliverdin, induced DNA ladders, and cleavage of Casp‐3 and PARP proteins in human CRC cells. Increased phosphorylated levels of the endoplasmic reticular (ER) stress proteins, protein kinase R‐like ER kinase (PERK), and eukaryotic initiation factor 2α (eIF2α) by CORM and CoPP were identified, and the addition of the PERK inhibitor, GSK2606414, inhibited CORM‐ and CoPP‐induced apoptosis. Increased GRP78 level and formation of the HO‐1/GRP78 complex were detected in CORM‐ and CoPP‐treated human CRC cells. A pro‐apoptotic role of HO‐1 against the viability of human CRC cells via induction of CO and ER stress was firstly demonstrated herein.

NEAT1 promotes colon cancer progression through sponging miR-495-3p and activating CDK6 in vitro and in vivo.

Recently, increasing evidence has indicated lncRNAs are powerful regulators in the progression of multiple tumors. Dysregulation of lncRNA NEAT1 has been recognized in many cancer types. Meanwhile, the studies on NEAT1 function have suggested that NEAT1 can serve as a crucial oncogene. Nevertheless, the investigation of NEAT1 in colon cancer is still few. In our study, the function of NEAT1 was studied in colon cancer. As we observed, NEAT1 level was obviously elevated in colon cancer cells. Then, HCT-116 and SW620 cells were stably infected with shRNA-NEAT1 for 48 hr. As exhibited, silence of NEAT1 could greatly repress colon cancer cell progression. Apoptosis of colon cancer cells was triggered and the cell cycle progression was remarkably inhibited by downregulation of NEAT1. Interestingly, as exhibited, miR-495-3p was obviously decreased in colon cancer cells and it significantly suppressed colon cancer progression. Subsequently, miR-495-3p was predicted as a target of NEAT1. CDK6 was speculated as the target of miR-495-3p and miR-495-3p modulated its expression negatively. Finally, it was indicated that NEAT1 promoted colon cancer development through modulating miR-495-3p and CDK6 in vivo. Taken these together, we reported that NEAT1 could sponge miR-495-3p to contribute to colon cancer progression through activating CDK6.

The relationship between the structural characteristics of lactobacilli-EPS and its ability to induce apoptosis in colon cancer cells in vitro

Colon cancer is one of the most common cancer around the world. Exopolysaccharides (EPSs) produced by lactobacilli as potential prebiotics have been found to have an anti-tumor effect. In this study, lyophilized EPSs of four Lactobacillus spp. for their impact on apoptosis in colon cancer cells (HT-29) was evaluated using flow cytometry. The relationship between capability of a lactobacilli-EPS to induce apoptosis and their monosaccharide composition, molecular weight (MW), and linkage type was investigated by HPLC, SEC, and NMR, respectively. Changes in apoptotic-markers were examined by qPCR and Western Blotting. EPSs were capable of inhibiting proliferation in a time-dependent manner and induced apoptosis via increasing the expression of Bax, Caspase 3 and 9 while decreasing Bcl-2 and Survivin. All EPSs contained mannose, glucose, and N-acetylglucosamine with different relative proportions. Some contained arabinose or fructose. MW ranged from 102–104Da with two or three fractions. EPS of L. delbrueckii ssp. bulgaricus B3 having the highest amount of mannose and the lowest amount of glucose, showed the highest apoptosis induction. In conclusion, lactobacilli-EPSs inhibit cell proliferation in HT-29 via apoptosis. Results suggest that a relationship exists between the ability of EPS to induce apoptosis and its mannose and glucose composition.

Activation of PTEN by inhibition of TRPV4 suppresses colon cancer development

Transient receptor potential vanilloid type 4 (TRPV4) is a Ca2+-permeable cation channel that is known to be an osmosensor and thermosensor. Currently, limited evidence shows that TRPV4 plays opposite roles in either promoting or inhibiting cancer development in different cancer types. Furthermore, the precise biological functions and the underlying mechanisms of TRPV4 in carcinogenesis are still poorly understood. In this study, we demonstrated that TRPV4 is upregulated in colon cancer and associated with poor prognosis. Contrary to the reported cell death-promoting activity of TRPV4 in certain cancer cells, TRPV4 positively regulates cell survival in human colon cancer in vitro and in vivo. Inhibition of TRPV4 affects the cell cycle progression from the G1 to S phase through modulating the protein expression of D-type cyclins. Apoptosis and autophagy induced by TRPV4 silencing attenuate cell survival and potentiate the anticancer efficacy of chemotherapeutics against colon cancer cells. In addition, PTEN is activated by inhibition of TRPV4 as indicated by the dephosphorylation and increased nuclear localization. Knockdown of PTEN significantly abrogates TRPV4 silencing induced growth inhibition and recovers the capability of clonogenicity, as well as reduced apoptosis in colon cancer cells. Thus, PTEN regulates the antigrowth effects induced by TRPV4 inhibition through both phosphatase-dependent and independent mechanisms. In conclusion, inhibition of TRPV4 suppresses colon cancer development via activation of PTEN pathway. This finding suggests that downregulation of TPRV4 expression or activity would conceivably constitute a novel approach for the treatment of human colon cancer.

Mitochondrial NOS1 suppresses apoptosis in colon cancer cells through increasing SIRT3 activity

Previous studies have suggested that nitric oxide (NO) which is synthetized by nitric oxide synthase (NOS) is closely related to the carcinogenesis and progression of colon cancer. However, the precise physiopathological role of NO on colon cancer remains unclear, and a lot of related studies focused on NOS2 and NOS3, but little on NOS1. Here, stable overexpression NOS1 of colon cancer cells were constructed to investigate whether NOS1 plays a special role in colon cancer. We observed that NOS1 protein was presented in mitochondria. Both the basal and cisplatin-induced mitochondrial superoxide were inhibited by NOS1, and the cisplatin-induced apoptosis was also inhibited by NOS1. Geldanamycin, a Hsp90 N-terminal inhibitor, was able to impede NOS1 translocation into mitochondria and reverse NOS1-induced apoptosis resistance. Importantly, SIRT3 activity was enhanced by NOS1, which contributes to the low level of mitochondrial superoxide and apoptosis resistance. Our data suggest a link between NOS1 and apoptosis resistance in colon cancer cells through mtNOS1-SIRT3-SOD2 axis. Furthermore, NOS1-induced apoptosis resistance could be reversed by inhibiting mitochondrial translocation of NOS1.

Naringenin-loaded nano-structured lipid carrier fortifies oxaliplatin-dependent apoptosis in HT-29 cell line

Abstract In the present study, we inspected the role of naringenin-loaded nanostructured lipid carriers (NLCs) in the induction of apoptosis in (HT-29) colon cancer cell in co-administration with oxaliplatin. The cytotoxicity behavior of nanoparticles was investigated by MTT assay and DAPI staining. To understand the molecular mechanism of formulation in induction program cell death, flow cytometric and Real-Time RT-PCR assays were applied. New formulation revealed a mean particle size of 98 ± 3 nm with homogenous dispersity, which was confirmed by SEM graphs. Naringenin and Oxaliplatin-induced cell death in HT-29 colon cancer by IC50 value of 150 ± 11.04 μM and 20 ± 2.25 μM, respectively. Loading Naringenin into new formulation declined the proportion of cell proliferation of HT-29 colon cancer from 47 ± 9.1% to 27 ± 5.3% (p

Tetrandrine inhibits colon carcinoma HT-29 cells growth via the Bcl-2/Caspase 3/PARP pathway and G1/S phase.

Tetrandrine (Tet) bisbenzylisoquinoline alkaloids isolated from Stephania tetrandra and other related species of Menispermaceae. It has been demonstrated to have positive therapeutic effects on cardiovascular disease, hypertension, silicosis, autoimmune diseases. In recent years, some reports have shown that Tet has anticancer activity in human cancers. To explore the pharmacological activity and mechanism of Tet on colon cancer and its unique advantages as a natural product. In the present study, analyses of the cell cycle, apoptosis, targets prediction, molecular docking, and alterations in protein levels were performed to elucidate how Tet functions in colon cancer. We found that Tet robustly induced arrest at the G1 phase in colon cancer cell line HT-29. It induced HT-29 cell apoptosis in a dose-dependent manner. Similarly, analysis of protein expression levels in HT-29 cells showed down-regulation of Bcl-2, pro-caspase 3, pro-caspase 8, PARP, cyclin D1 (CCND1), cyclin-dependent kinase 4 (CDK 4), and up-regulation of Bax, active caspase 3, and active caspase 8. These results indicate that Tet induces apoptosis of colon cancer cells through the mitochondrial pathway and caspase family pathway. Molecular docking showed interaction effects and binding energy. Comparing with the CDK4 inhibitors ribociclib and palbociclib, the docking energy is similar to the docked amino acid residues. Therefore, we conclude that Tet and the CCND1/CDK4 compound could form hydrogen bonds and a stable compound structure, which can inhibit colon cancer cells proliferation by regulating CCND1/CDK4 compound and its downstream proteins phosphorylated Rb (p-Rb). In summary, Tet may be a potential drug for colon cancer therapy.

Histone Deacetylase Inhibitors Sensitize TRAIL-Induced Apoptosis in Colon Cancer Cells.

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is considered as a promising anti-cancer therapeutic. However, many cancers have been found to be or to become inherently resistant to TRAIL. A combination of epigenetic modifiers, such as histone deacetylase inhibitors (HDACi’s), with TRAIL was effective to overcome TRAIL resistance in some cancers. Broad spectrum HDACi’s, however, show considerable toxicity constraining clinical use. Since overexpression of class I histone deacetylase (HDAC) has been found in colon tumors relative to normal mucosa, we have focused on small spectrum HDACi’s. We have now tested agonistic receptor-specific TRAIL variants rhTRAIL 4C7 and DHER in combination with several class I specific HDACi’s on TRAIL-resistant colon cancer cells DLD-1 and WiDr. Our data show that TRAIL-mediated apoptosis is largely improved in WiDr cells by pre-incubation with Entinostat-a HDAC1, 2, and 3 inhibitor- and in DLD-1 cells by RGFP966-a HDAC3-specific inhibitor- or PCI34051-a HDAC8-specific inhibitor. We are the first to report that using RGFP966 or PCI34051 in combination with rhTRAIL 4C7 or DHER represents an effective cancer therapy. The intricate relation of HDACs and TRAIL-induced apoptosis was confirmed in cells by knockdown of HDAC1, 2, or 3 gene expression, which showed more early apoptotic cells upon adding rhTRAIL 4C7 or DHER. We observed that RGFP966 and PCI34051 increased DR4 expression after incubation on DLD-1 cells, while RGFP966 induced more DR5 expression on WiDr cells, indicating a different role for DR4 or DR5 in these combinations. At last, we show that combined treatment of RGFP966 with TRAIL variants (rhTRAIL 4C7/DHER) increases apoptosis on 3D tumor spheroid models.

Targeting Akt by SC66 triggers GSK-3\u03b2 mediated apoptosis in colon cancer therapy

BackgroundColon cancer is one of the three common malignant tumors, with lower 5 years survival rate. Akt is an important therapeutic target, while SC66 is a novel allosteric AKT inhibitor, which enhances the therapeutic effect in several types of cancer. However, the molecular mechanisms of targeting AKT by SC66 during colon cancer therapy are not well understood.MethodsThe biological role of GSK-3β in colon cancer growth suppression induced by SC66 was detected in vitro and in vivo. Hoechst 33342 and crystal violet staining were used to determine whether targeting AKT affected apoptosis and cell proliferation. The CCK8 assay was utilized to analyze cell viability. The expression levels of Akt, GSK-3β, Bax, Bcl-xL, p53 and PUMA were measured by immune blotting. Xenograft mouse model was established to study the antitumor effect of SC66 in vivo.ResultsOur results show that SC66 induced significantly colon cancer cell apoptosis, accompanied with Akt inactivation. After AKT inhibition, activated GSK-3β interacted with Bax directly, leading to Bax oligomerization and activation. Knocking down GSK-3β abrogated SC66-triggered Bax activation and apoptosis, which was enhanced by over-expressed GSK-3β. In addition, the expression level of Bcl-xL was down-regulated while p53 had no function during SC66-induced apoptosis. Furthermore, colon cancer growth was suppressed by SC66 therapy in vivo.ConclusionTaken together, these data indicated that the novel small molecule AKT inhibitor SC66 shows visible antitumor effects via the AKT/GSK-3β/Bax axis in vitro and in vivo. Our results provide a rational basis for the development of targeting-GSK-3β, which may serve as a potential biomarker and yield meaningful benefits for colon cancer patients in the future.

Proteomic analysis of flavokawain C-induced cell death in HCT 116 colon carcinoma cell line

Flavokawain C (FKC), a naturally occurring chalcone, has previously been shown to inhibit the growth of colon carcinoma HCT 116 cells through induction of apoptosis and cell cycle arrest. However, the possible underlying mechanisms of cell death as a response to FKC treatment remains unclear. In this study, we performed proteomic analysis of HCT 116 cells treated with FKC to identify proteins that change in abundance. This was followed by bioinformatic analysis to predict possible associated molecular targets or pathways involved in the observed effects of FKC. A total of 35 proteins that changed in abundance (17 increased and 18 decreased) were identified through two-dimensional gel electrophoresis followed by matrix-assisted laser desorption ionisation time-of-flight mass spectrometry (MALDI-TOF/TOF MS). Using the Ingenuity Pathway Analysis (IPA), these proteins were predicted to be involved in cell death and survival, cell cycle, cellular growth and proliferation, protein synthesis, post-translational modification and amino acid metabolism by. Further analysis of the transcript levels of selected proteins using qPCR showed that some of the genes exhibited similar change of profile to that of the proteins'. Our results have provided novel insights into the potential molecular mechanisms underlying FKC-induced apoptosis or cell death in colon cancer cells.

Genome-wide expression profiling-based copy number variations and colorectal cancer risk in Chinese.

Genetic factors play important roles in colorectal carcinogenesis. This study was aimed to evaluate the effects of gene expression-related copy number variations (CNVs) on the risk of colorectal cancer in Chinese. Expression Quantitative Trait Locus (eQTL) mapping was conducted to explore the most regulatable gene expressions by CNVs among the whole genome based on publicly available data. Then a case-control study was performed to evaluate the associations between copy numbers of the most regulatable genes and colorectal cancer. The influence of the target CNVs on the expression of corresponding gene and protein was verified in colorectal tissue, and the biological effects of these CNVs on cell-cycle arrest and apoptosis of colon cancer cell lines were further detected. The eQTL revealed the most significant association between CNV of HM3_CNP_342 and gene expressions of human leukocyte antigen (HLA)-DQA1 and HLA-DQB1 among the whole genome. The later case-control study found that amplified HLA-DQB1 was inversely associated with colorectal cancer risk (odds ratio = 0.73; 95% confidence interval: 0.58-0.93), especially among those with a family history of cancer. The positive association between amplified HLA-DQB1 and upregulation of gene and protein was validated in colorectal tissue. In addition, overexpression of HLA-DQB1 in dendritic cells promoted cell-cycle arrest and apoptosis of cocultured SW480 and HCT116 cell lines, and vice versa. Our study suggests that the amplified copy number of HLA-DQB1 is associated with lower risk of colorectal cancer and able to induce the apoptosis of colon cancer cells, which implies the potential of HLA class II in cancer predisposition and immunotherapy.

Dimethyl Sulfoxide Extract of Dianthus carmelitarum Induces S Phase Arrest and Apoptosis in Human Colon Cancer Cells

Although several studies have investigated the cytotoxic effects of different Dianthus species, there has been only limited research into the cytotoxic effect of Dianthus carmelitarum. The purpose of this research was to evaluate the phenolic characterization and the cytotoxic effect of D. carmelitarum on human colon cancer (WiDr) cells and the possible mechanisms involved. Total polyphenolic contents (TPC) and phenolic characterization of the extract were evaluated using the Folin-Cioceltau method and reversed-phase high performance liquid chromatography (RP-HPLC), respectively. The cytotoxic activity of the extract was determined using the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay. The mechanism involved in the extract’s cytotoxic effect was then evaluated in terms of apoptosis and the cell cycle using flow cytometry, while mitochondrial membrane potential (MMP) was investigated using the fluorometric method. The TPC value of the extract was 784.8 ± 40.3 mg gallic acid equivalent per 100 g sample, and sinapic acid and benzoic acid were detected as major phenolics in the extract. D. carmelitarum extract exhibited a selective cytotoxic effect (3.6-fold) on WiDr cells compared to normal colon cells. The extract induced cell cycle arrest at the S phase and apoptosis via reduced MMP in WiDr cells. Phytomedical and nutraceutical applications of D. carmelitarum may represent promising approaches in the treatment of cancer.

Isorhamnetin in Tsoong blocks Hsp70 expression to promote apoptosis of colon cancer cells.

The roots of Codonopis bulleynana Forest ex diels (cbFed), locally known as Tsoong, have been used as a tonic food. Tsoong has wide range of pharmacological effects, including anticancer efficacy. In the present study, the anticancer activity of Tsoong and its potential molecular mechanisms were investigated. Isorhamnetin, a flavonol aglycone, is important compound and metabolite in Tsoong. It can promote apoptosis of colon cancer cells through up-regulating apoptosis-related genes (Apaf1, Casp3 and Casp9) because it blocks Hsp70 genes (Hspa1a, Hspa1b and Hspa8). These were verified by in vitro and in vivo experiments. In vitro, cell counting kit-8 (CCK-8) assays and flow cytometry in HCT116 and SW480 colon cancer cell were used to assess the anti-proliferation and apoptosis-promoting activities of Tsoong. In vivo, the antitumor effect of Tsoong was assessed in colon cancer-bearing nude mice as a xenograft model. These results show that Isorhamnetin is very critical in Tsoong because Tsoong can down-regulate Hsp70 genes and promote apoptosis of colon cancer cells by inhibiting Hsp70 largely due to the efficacy of Isorhamnetin. Our results may ultimately help in the development of diagnostic and therapeutic strategies to control this devastating disease.

Effects of As2O3 and Resveratrol on the Proliferation and Apoptosis of Colon Cancer Cells and the hERG-mediated Potential Mechanisms.

: Background:As2O3 and resveratrol have been widely considered to be effective in anti-cancer therapies and the underlying mechanisms have been reported extensively. However, the combined treatment effect and potential target of As2O3 and resveratrol in the treatment of tumors remains elusive. The purpose of this study was to investigate the benefits and efficacy of As2O3 in combination with resveratrol in the treatment of colon cancer, as well as looking for new targets that could provide alternative explanation of the efficacy of drugs.Methods:The proliferation of cancer cells was measured by the MTT and EdU staining assay, while the apoptosis of cancer cells was determined by the flow cytometry. Western blot and immunoprecipitation were performed to measure the expression levels of proteins and the interaction between hERG and integrin β1, respectively.Results:In this study, we found that both As2O3 and resveratrol can effectively inhibit cell proliferation and promote cell apoptosis in colon cancer, and the combined effect of the two drugs on colon cancer cells is more preeminent. The combination of As2O3 with resveratrol, on the one hand reduced the expression of hERG channels on the membrane, and on the other hand weaken the binding between hERG and integrin β 1, which may be the main cause of downstream signaling pathways alterations, including the activation of the apoptotic pathway.Conclusion:Taken together, hERG, as a subunit of potassium ion channel on the cell membrane, is highly likely to be involved in the As2O3 and resveratrol induced intracellular signaling cascade disorder, and this novel signaling pathway that sustains the progression of colon cancer may be a promising therapeutic target for human colon cancer treatment in the future.

Novel Endoperoxides Increase Apoptosis in Cancer, but not Normal Cells, and May Involve Differences in Transferrin Receptor (TfR) Expression

Artemisinin (ART), a common anti‐malarial drug, and its analogs are also useful as repurposed anti‐cancer drugs, but their properties are not fully elucidated. We previously synthesized novel trioxane (DMR) and dioxazanine (HSM) ART analogs and showed that: a. at low doses (5–10 μM), HSM > than DMR in inducing apoptosis in human colon and lung cancer cells, but not in normal lung cells; b. The actions involved reactive oxygen species (ROS) (Faseb J, ′18:32, 616.2). TfR expression is increased in cancer vs. normal cells. Thus, we hypothesize that, in cancer cells, TfR increases [Fe2+]i which acts on the endoperoxide to produce ROS and induce apoptosis. We examined the mechanism of action of DMR/HSM in inducing apoptosis in human breast, lung, and colon cancer cell lines as compared to normal cell lines. To increase the efficacy of the drug, we also designed and synthesized a 3rd novel analog with dual dioxazanine pharmacophores, PMW.Confluent normal (Breast: MCF10A, Lung: A549) and cancer (Breast: MCF7, Colon: T84, Lung: A549) cells were treated (18 H) with 1–50μM of DMR, HSM or PMW±Deferoxamine (DFO, iron chelator; 1–25 μM). Cells were stained with FITC‐Annexin V (apoptosis), propidium iodide (cell death) or CellRox Green (mitochondrial/nuclear ROS), imaged and quantified by flow cytometry and/or microscopy (Image J). Normal and cancer cell lysates (30 μg) were subjected to SDS‐PAGE and immunoblotting with polyclonal TfR antibody or anti‐GAPDH (control).As in other cancer cells, both DMR and HSM (5 – 50μM) induced apoptosis in breast cancer, but not normal, cells. In contrast to A549 lung cells, where HSM was more effective than DMR, in MCF7 breast cells, 50μM DMR was more efficient (~40%) in inducing apoptosis than HSM (10%). This dictates the development of novel tissue‐specific analogs. The new analog, PMW (1 – 50μM, 18H) did not induce apoptosis in the cancer cells. The larger size of PMW may have slowed entry, suggesting longer incubations.Image J analysis (mean pixel intensity; 18 H) of CellRox+ lung cells (n=3) showed that HSM dose‐dependently increased ROS in cancer A549: (DMSO: 1.5±0.2; HSM, 5 μM: 19±2; 10 μM: 48±4; 50 μM: 59±2); but not normal BEAS2B: (DMSO: 1.0±0.3; HSM, 5 μM: 1.8±1; 10 μM: 2.2±0.4; 50 μM: 2.9±2). Similarly, in breast cancer cells (n=3), DMR dose‐dependently increased ROS in MCF7 (DMSO: 1.0±0.3; DMR, 5 μM: 12±2; 10 μM: 51±5; 50 μM: 42±3); but not in MCF10A (DMSO: 1.0±0.2; DMR, 5 μM: 1.6±1; 10 μM: 3.1±1; 50 μM: 2.5±1).Immunoblotting detected a distinct 94 kDa TfR protein in colon, lung, and breast cancer, but not normal cells. The effect of DMR/HSM±DFO on apoptosis was examined to study the role of TfR. Albeit showing an inhibitory trend, DFO did not significantly alter ART analogs actions (% Annexin V+ cells,18 H: A549: HSM,10μM: 46±4; HSM+5μM DFO: 38±6; HSM +10μM DFO: 33±9; MCF7: DMR,10μM: 36±4; DMR+5μM DFO: 31±7; DMR+10μM DFO: 29±5; n≥3).Synthesizing novel ART‐analogs with improved pharmacokinetics to specifically target cancer cells and elucidating their mechanism of action will help develop new alternatives to treat cancer.Support or Funding InformationNSF ‐ MRI: DBI‐1427937 to JS; Ben U Funds to JS and DMR; UIC Funds to MCR; APS‐STRIDE to UD; APS‐UGSRF to MHThis abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Protopine isolated from Nandina domestica induces apoptosis and autophagy in colon cancer cells by stabilizing p53.

The tumor suppressor p53 plays essential roles in cellular protection mechanisms against a variety of stress stimuli and its activation induces apoptosis or autophagy in certain cancer cells. Here, we identified protopine, an isoquinoline alkaloid isolated from Nandina domestica, as an activator of the p53 pathway from cell-based natural compound screening based on p53-responsive transcription. Protopine increased the p53-mediated transcriptional activity and promoted p53 phosphorylation at the Ser15 residue, resulting in stabilization of p53 protein. Moreover, protopine up-regulated the expression of p21WAF1/CIP1 and BAX, downstream genes of p53, and inhibited the proliferation of HCT116 colon cancer cells. Apoptosis was elicited by protopine as indicated by caspase-3/7 activation, poly ADP ribose polymerase cleavage, and increased population of Annexin V-FITC-positive cells. Furthermore, protopine induced the formation of microtubule-associated protein 1 light chain 3 (LC3) puncta and LC3-II turnover, typical biochemical markers of autophagy, in HCT116 cells. Our findings suggest that protopine exerts its antiproliferative activity by stimulating the p53 pathway and may have potential as a chemopreventive agent for human colon cancer.

MicroRNA‑25/ATXN3 interaction regulates human colon cancer cell growth and migration.

The present study aimed to investigate the function of microRNA-25 (miR-25) in human colon cancer cell viability and migration in addition to the underlying possible mechanisms. miR-25 expression was upregulated in patients with colon cancer compared with the control group. Reverse transcription-quantitative polymerase chain reaction and gene chip technology were used to analyze the alterations of miR-25 in patients with colon cancer. Cell viability and cell migration were analyzed using MTT and wound healing assays, respectively, apoptosis was analyzed using flow cytometry, and western blot analysis was conducted to determine the protein expression of ataxin-3 (ATXN3), apoptosis regulator Bax (Bax) and cyclin D1. Overexpression of miR-25 increased cell viability and migration, decreased apoptosis, decreased caspase-3/9 activity level in addition to decreased Bax protein expression, and increased cyclin D1 protein expression in colon cancer cells. Furthermore, miR-25 was demonstrated to target ATXN3 and suppress ATXN3 protein expression. Downregulation of miR-25 induced apoptosis of colon cancer cells via increased expression ATXN3. Small interfering-ATXN3 inhibited the anti-cancer effects of miR-25 downregulation in colon cancer. Collectively, the present results demonstrated that miR-25 promoted human colon cancer cell viability and migration by regulating ATXN3 expression.

The anti-cancer effect of Echis coloratus and Walterinnesia aegyptia venoms on colon cancer cells

Colorectal cancer (CRC) is one of the most prevalent causes of cancer mortality worldwide. Saudi patients are more likely to present CRC at advanced disease stages and at younger ages compared to other populations. The present study evaluated the anti-cancer effects of venoms extracted from indigenous snakes on the growth arrest of colon cancer cells. Walterinnesia aegyptia venom showed a significant cell death proportions against LoVo cells only, whereas Echis coloratus venom-induced apoptosis in LoVo, HTC-116, and HT-29 colon cancer cells. Also, it suppressed the levels of cyclin D1 and survivin, overexpressed p53 and p21 in HCT-116, HT-29, and LoVo cells. Our results provide evidence that snake venoms induce the growth arrest of colon cancer cells via cell cycle arrest, which promotes the direction toward further investigating the innovative therapeutic strategy using biologically synthesized snake venoms.

MiRNA‑766 induces apoptosis of human colon cancer cells through the p53/Bax signaling pathway by MDM4

miRNAs are closely associated with tumor genesis and development. The present study investigated the role of the expression of miRNA-766 in the survival of patients with colon cancer and the underlying molecular mechanisms. Reverse transcription-quantitative polymerase chain reaction analysis and microarray analysis were used to analyze the expression of miRNA-766. The results revealed that the expression of miRNA-766 was decreased in patients with colon cancer. The overall survival and disease-free survival rates of patients with colon cancer with a high expression of miRNA-766 were prolonged, compared with those with a low expression of miRNA-766. The overexpression of miRNA-766 reduced cell growth and induced apoptosis in colon cancer cells through suppression of the MDM4/p53 pathway. By contrast, the downregulation of miRNA-766 promoted cell growth and reduced apoptosis in colon cancer cells through activation of the MDM4/p53 pathway. The promotion of MDM4 attenuated the anticancer effect of miRNA-766 in colon cancer cells. These results demonstrated that miRNA-766 induced cell apoptosis in human colon cancer through MDM4/p53.

The Combined Use of Phenothiazines and Statins Strongly Affects Doxorubicin-Resistance, Apoptosis, and Cox-2 Activity in Colon Cancer Cells.

Since none of the multidrug resistance (MDR) modulators tested so far found their way into clinic, a novel approach to overcome the MDR of cancer cells has been proposed. The combined use of two MDR modulators of dissimilar mechanisms of action was suggested to benefit from the synergy between them. The effect of three phenothiazine derivatives that were used as single agents and in combination with simvastatin on cell growth, apoptosis induction, activity, and expression of cyclooxygenase-2 (COX-2) in doxorubicin-resistant colon cancer cells (LoVo/Dx) was investigated. Treatment of LoVo/Dx cells by phenothiazine derivatives combined with simvastatin resulted in an increase of doxorubicin cytotoxicity and its intracellular accumulation as compared to the treatment with phenothiazine derivatives that were used as single agents. Similarly, LoVo/Dx cells treated with two-component mixture of modulators showed the reduced expression of ABCB1 (P-glycoprotein) transporter and COX-2 enzyme, both on mRNA and protein level. Reduced expression of anti-apoptotic Bcl-2 protein and increased expression of pro-apoptotic Bax were also detected. Additionally, COX-2 activity was diminished, and caspase-3 activity was increased to a higher extent by phenothiazine derivative:simvastatin mixtures than by phenothiazine derivatives themselves. Therefore, the introduction of simvastatin strengthened the anti-MDR, anti-inflammatory, and pro-apoptotic properties of phenothiazines in LoVo/Dx cells.