Human Colon Cancer DLD-1 Cells Research Articles

Oncofetal morphogenesis similar to embryonic gut formation by a subpopulation of DLD-1 human colon cancer cells

Cancer stem cells (CSC) are thought to be responsible for cancer phenotypes and cellular heterogeneity. Here we demonstrate that the human colon cancer cell line DLD1 contains two types of CSC-like cells that undergo distinct morphogenesis in the reconstituted basement membrane gel Matrigel. In our method with cancer cell spheroids, the parent cell line (DLD1-P) developed grape-like budding structures, whereas the other (DLD1-Wm) and its single-cell clones dynamically developed worm-like ones. Gene expression analysis suggested that the former mimicked intestinal crypt-villus morphogenesis, while the latter mimicked embryonic hindgut development. The organoids of DLD1-Wm cells rapidly extended in two opposite directions by expressing dipolar proteolytic activity. The invasive morphogenesis required the expression of MMP-2 and CD133 genes and ROCK activity. These cells also exhibited gastrula-like morphogenesis even in two-dimensional cultures without Matrigel. Moreover, the two DLD1 cell lines showed clear differences in cellular growth, tumor growth and susceptibility to paclitaxel. This study also provides a simple organoid culture method for human cancer cell lines. HT-29 and other cancer cell lines underwent characteristic morphogenesis in direct contact with normal fibroblasts. Such organoid cultures would be useful for investigating the nature of CSCs and for screening anti-cancer drugs. Our results lead to the hypothesis that CSC-like cells with both invasive activity and a fetal phenotype, i. e. oncofetal CSCs, are generated in some types of colon cancers.

Single-copy Snail upregulation causes partial epithelial-mesenchymal transition in colon cancer cells

BackgroundEpithelial-mesenchymal transition (EMT) is an embryonic programme implicated in cancer stem cells, metastasis and therapeutic resistance. Its role in cancer progression remains controversial because the transition can be partial or complete in different models and contexts.MethodsUsing human colon cancer DLD-1 cells, we engineered a cell line with a single-copy of Snail that was doxycycline-inducible and compared it to existing EMT models in DLD-1. The effect of Snail upregulation was characterised functionally, morphologically, and by transcriptional profiling and protein expression.ResultsInduction with doxycycline increased Snail expression to a level similar to that observed in cancer cell lines spontaneously expressing Snail and results in partial EMT. In comparison, higher levels of overexpression arising from introduction of episomal-Snail, results in complete EMT. DLD-1 cells with partial EMT show chemoresistance in vitro, increased tumour growth in vivo and decreased apoptosis.ConclusionsThese findings highlight that the amount of bioavailable Snail can dictate phenotypic outcome and that partial EMT may be a preferred outcome of models operating within a natural range of Snail overexpression.

Hyaluronic acid-targeted protein capped AMSN for inhibiting tumour growth and side effects by the controlled release of curcumin and doxorubicin

Ample attention has focused on Hyaluronic acid (HA) targeted Soy protein (SOY) capped Aminated Mesoporous Silica (AMSN), a novel combinatorial approach for the effective co-delivery of curcumin (CUR) and doxorubicin (DOX) for colon cancer. CUR was loaded in the inner core of AMSN via electrostatically followed by capping with SOY. HA acts as a targeting ligand and DOX carrier. The modified structural elucidation of drug carrier was done by FT-IR, XRD, DLS, EDX and BET adsorption isotherm. The morphological detection was carried out by FE-SEM, AFM and TEM analyses.The dual drug delivery system (DDDS) having maximum drug loading efficiency of 81.0 % for DOX and 70.0 % for CUR. The pH dependent release study shows maximum release (64.2 % CUR and 80.0 % DOX) at tumour pH. The effective haemolytic activity (<3.0 %) and antioxidant property (>70.0 %) reveal the practical applicability of DDDS. MTT assay shows 25.0 % anticancer activity in DLD-1 human colon cancer cell lines and no toxic to cardiac cells (H9C2), which was further confirmed by apoptosis assay. Material without drug shows < 90.0 % viability in (L929) normal cells confirmed the non-toxic nature and proved the novel potency towards drug delivery applications.

Parecoxib expresses anti-metastasis effect through inhibition of epithelial-mesenchymal transition and the Wnt/β-catenin signaling pathway in human colon cancer DLD-1 cell line.

Colorectal cancer is the third leading cause of cancer death in Taiwan. Current treatments involve combination of surgical resection, radiation, and chemotherapy. These treatments have demonstrated to increased five-year survival of a patient with colorectal cancer. However, metastasis is a major capability of cancer cells that causes poor prognosis, recurrence, and even death. Epidemiological and clinical studies have suggested the use of non-steroidal anti-inflammatory drugs (NSAIDs) as an effective class of compounds to prevent colon cancer. Parecoxib is an NSAID and the only parenterally administered selective cyclooxygenase (COX)-2 inhibitor. In this study, we evaluated whether parecoxib inhibits the metastasis of DLD-1 human colon cancer cells, a COX-2 null cell line, and the underlying mechanism. Cell migration of the DLD-1 cells was significantly inhibited by parecoxib treatment as shown by the Transwell migration assay. This enhanced anti-migration effect was correlated with the attenuated phosphorylation of Akt, expression of vimentin (a mesenchymal marker), and β-catenin, and corresponded with the upregulated GSK3β and E-cadherin (an epithelial marker). These findings suggested that parecoxib could inhibit the epithelial-mesenchymal transition (EMT) and metastasis in human colon cancer cells by downregulating β-catenin. Thus, parecoxib could provide a novel prospective strategy for a combination treatment with chemotherapeutic drugs against metastasis of human colon cancer.

Effects of silkworm pupa protein on apoptosis and energy metabolism in human colon cancer DLD-1 cells

ObjectiveTo investigate the effects of silkworm pupa (Bombyx mori) protein (SPP) on cell proliferation, apoptosis and energy metabolism in human colon cancer cells DLD-1. MethodsCCK-8 was used to detect cell proliferation rate after 72 h of cell culture for the control group (normal cultured DLD-1 cells) and SPP dose groups; Annexin-V/PI was applied to observe cell apoptosis; XFe24 Extracellular Flux Analyzer was used to detect cell mitochondrial respiratory function and glycolytic function. ResultsComparing with the control, SPP significantly inhibited the proliferation of DLD-1 cells with all the dosage tested (P < 0.01); flow cytometry showed that SPP significantly promoted apoptosis (P < 0.05). Additionally, SPP could significantly inhibited mitochondrial metabolism and glycolysis of DLD-1 cells and decreased cell energy metabolism in all groups treated with different doses. ConclusionSPP can cause oxidative damage, promote apoptosis, and reduce mitochondrial respiratory and glycolysis rate in colon cancer DLD-1 cells, which reveals that SPP has the potential to serve as the anti-cancer drugs in the future, but further experimental evidence is needed.

GSTs, MRP and Apoptototic Markers in DLD-1 Human Colon Cancer Cell Line Before and After 5-FU Treatment

Multidrugresistance is an important factor limiting the effect of chemotherapy on cancer treatment. Disorders of drug transport and apoptosis, deterioration of redox homeostasis are among the main mechanisms that lead to multidrug resistance. The aim of this study was to determine the effect of 5-FU on GST isozymes, drug resistance proteins and apoptotic proteins before and after 5-Flourouracil application on DLD-1 colon cancer cell line. The cytotoxic effect of 5-FU was measured by WST-1test and, the efficiency of drug application was, also, proved by double staining via Hoechst 33342 with Propidium iodide. Next, the expression levels of GST isozymes, drug resistance proteins and apoptotic proteins were determined by immunocytochemistry. The cytotoxic effect of 5-FU at different doses on DLD-1 colon cancer cell line was determined by WST-1 method. MRP-2, 3, 6, 7 of drug resistance proteins; GSTA1, GSTM1, GSTT1, GSTZ1, GSTK1 and GSTO1 of GST proteins; bcl-2, caspase-3, p38, and p53, which are apoptotic proteins, have higher expression in the drug-treated DLD-1 cell line. GSTS1, MDR-1 and MRP-1expressions were not immunocytochemically different. It was determined that there is a direct correlation between the level of cytotoxicity and applied drug concentration. The cytotoxic effect of the drug increased with the increase in the dose of the drug. In this study, as first in the literature, the expression levels of some apoptotic markers, GST isozymes and drug resistance proteinswere evaluated togetherand except GSTS1, MDR-1 and MRP-1, they were all upregulated with respect to the control group after 5-FU administration.

Flavonoid Glycoside Diosmin Induces Apoptosis and Cell Cycle Arrest in DLD-1 Human Colon Cancer Cell Line

The purpose of this study was to see if diosmin induced apoptosis and inhibited cell proliferation in DLD-1 cell lines. The assays such as MTT, DCFDA, AO/EtBr, cell cycle analysis, annexin V-FITC apoptosis by flow cytometry, gene expression analysis were done to evaluate the in vitro anti-colon cancer potential of diosmin in DLD-1 human colon cancer cell line. While analyzing the results of MTT assay it is observed that when different concentrations of diosmin were induced, it was discovered that DLD-1 cells were killed in a dose-dependent manner. Diosmin mediated apoptosis induction is observed through AO/EtBr double staining method. Diosmin treatment in DLD-1 cell line generates high amount of ROS which is being analyzed using ROS DCFDA assay. While using flow cytometry to investigate the effect of diosmin on cell cycle distribution, it was found that diosmin-induced cell cycle arrest occurs in the S phase. When diosmin is administered, the proportion of surviving cells decreases, confirming the existence of cell death induction via apoptosis using the annexin V staining method. Diosmin upregulated mRNA levels expression of p53 and p21, indicating that diosmin induced S phase arrest and apoptosis in DLD-1 cells is controlled in part by the p21/p53 signaling pathway.

Understanding of cell death induced by the constituents of Taxus yunnanensis wood

The ethanol extract from the wood of Taxus Yunnanensis (TY) induced apoptosis in all cancer cell lines tested, which was mainly due to activation of an extrinsic pathway in human colon cancer DLD-1 cells. The extrinsic pathway was activated by the upregulation of the expression levels of Fas and TRAIL/DR5, which led to the activation of caspase-8. Of note, the machinery of this increase in expression was promoted by the upregulation of MIR32a expression, which silenced MIR34a-targeting E2F3 transcription factor. Furthermore, ectopic expression of MIR32a or siR-E2F3 silencing E2F3 increased Fas and TRAIL/DR5 expression. Thus, the extract activated the extrinsic pathway through the MIR34a/E2F3 axis, resulting in the autocrine and paracrine release of TRAIL, and upregulated expression of death receptors Fas and DR5 in the treated DLD-1 cells, which were functionally validated by Fas immunocytochemistry, and using anti-Fas and anti-TRAIL antibodies, respectively. In vivo, TY showed significant anti-tumor effects on xenografted and syngeneic model mice. The extract may also aid in chemoprevention by selectively making marked tumor cells susceptible to the tumor immunosurveillance system.

Biosynthesized iron oxide nanoparticles: Cytotoxic evaluation against human colorectal cancer cell lines

Recent research reveals the impending importance of nanoparticles in medicine. Among various deadly diseases, cancer is one of the most dangerous categories for which no treatment is currently available other than surgery, chemotherapy, radiotherapy, etc. One major issue with these treatments is the side effect such as fatigue, pain, hair loss, vomiting, etc. So a better alternative is extremely desirable in these highly demanding times. Iron oxide nanoparticles (NPs) have attracted wide interest due to their superparamagnetic properties, nontoxicity and have been used in many fields. Iron oxide NPs are used in cancer magnetic nano therapy because of their magneto-spin effects in free radical reactions and ability to produce oxygen radicals. Iron oxide NPs may also be used in magnetic hyperthermia as a cancer treatment method. In the present study, we studied the apoptosis-inducing activity of biosynthesized iron oxide NPs synthesized via green method using Pimenta dioica leaf extract. The extent of cell viability was investigated using MTT assay. It was observed that the iron oxide NPs significantly reduce the cell viability in a concentration-dependent manner. The studies confirm that the biosynthesized iron oxide NPs have an efficient growth-inhibitory effect on DLD-1 human colon cancer cells and are less toxic on normal L929 (fibroblast) cells.

Structural and functional remodeling of mitochondria as an adaptive response to energy deprivation

Cancer cells bioenergetics is more dependent on glycolysis than mitochondrial oxidative phosphorylation, a phenomenon known as the Warburg Effect. It has been proposed that inhibition of glycolysis may selectively affect cancer cells. However, the effects of glycolysis inhibition on mitochondrial function and structure in cancer cells are not completely understood. Here, we investigated the comparative effects of 2-deoxy-d-glucose (2-DG, a glucose analogue, which suppresses cellular glycolysis) on cellular bioenergetics in human colon cancer DLD-1 cells, smooth muscle cells, human umbilical vein endothelial cells and HL-1 cardiomyocytes. In all cells, 2-DG treatment resulted in significant ATP depletion, however, the cell viability remained unchanged. Also, we did not observe the synergistic effects of 2-DG with anticancer drugs doxorubicin and 5-fluorouracil. Instead, after 2-DG treatment and ATP depletion, mitochondrial respiration and membrane potential were significantly enhanced and mitochondrial morphology changed in the direction of more network organization. Analysis of protein expression demonstrated that 2-DG treatment induced an activation of AMPK (elevated pAMPK/AMPK ratio), increased mitochondrial fusion (mitofusins 1 and 2) and decreased fission (Drp1) proteins. In conclusion, this study suggests a strong link between respiratory function and structural organization of mitochondria in the cell. We propose that the functionality of the mitochondrial network is enhanced compared to disconnected mitochondria.

In vitro co-delivery evaluation of PEGylated nano-liposome loaded by glycyrrhizic acid and cisplatin on cancer cell lines

Cisplatin, a platinum-based drug, is widely used in cancer treatment but is associated with significant side effects; new treatment delivery methods must be developed which enhance treatment efficiency while decreasing the sequelae of chemotherapy. The aim of this study was to develop novel liposomal nano-particles (NPs) loaded with two drugs including cisplatin and glycyrrhizic acid. This study hypothesized that introducing glycyrrhizic acid, as an adjuvant treatment, and cisplatin, as a chemotherapeutic agent, into a co-delivery system can enhance the therapeutic effect. In this study, the synthetic method and specifications of NPs were evaluated. After surface modification by polyethylene glycol (PEG), the size and the zeta potential of NPs were reported as 81.6 nm and − 30.7 mV, respectively. DLD-1 and LIM-2405 human colon cancer cell lines were then applied to evaluate the cytotoxicity of NPs using an MTT assay. The results revealed that IC50 for DLD-1, as a resistant cell line to cisplatin, decreased by 48% on co-delivery system treatment. Furthermore, to determine the proliferative potential of cell lines and DNA damage on cancerous cells after treatment by NPs and cisplatin in free form, the cell proliferation assay and immunocytochemistry method were performed. The results showed that a co-delivery system caused more than 43% DNA damage to cancerous cells compared with the free form of cisplatin. The finding of this study demonstrates that the co-delivery system has a significant anti-cancer efficiency compared with the free form of cisplatin. To conclude, the results of this study demonstrate a possible application of glycyrrhizic acid as an adjuvant treatment for cisplatin on co-delivery systems.

Endomorphin-2 Analog Inhibits the Growth of DLD-1 and RKO Human Colon Cancer Cells by Inducing Cell Apoptosis.

BackgroundIn developed countries, colon cancer is a leading cause of cancer-associated mortality. Dietary changes have resulted in an increased incidence of colon cancer in Asia. This study aimed to investigate the effects of the structural analog of endomorphin-2 (H-Tyr-Pro-Phe-Phe-NH2) on human colon cancer cells in vitro.Material/MethodsHuman DLD-1 and RKO colon cancer cells and CCD-18Co normal human colonic fibroblasts were treated with increasing doses of the structural analog of endomorphin-2. Cells underwent the MTT assay, fluorescence confocal flow cytometry, and Hoechst 33258 staining to investigate cell proliferation, the cell cycle, and apoptosis. Western blot was used to measure the expression levels of poly(ADP-ribose) polymerase-1 (PARP-1), cytochrome c, caspase-3, and caspase-9. The 2′,7′-dichlorofluorescein diacetate (DCFH-DA) fluorescence method measured reactive oxygen species (ROS).ResultsCell proliferation of DLD-1 and RKO cells was inhibited by the endomorphin-2 analog in a dose-dependent manner, and a 100 μM dose reduced DLD-1 and RKO cell proliferation by 28% and 23%, respectively, at 72 h. Endomorphin-2 analog induced cell apoptosis and the generation of ROS, activated caspase-3 and caspase-9, and increased the levels of p53 and cytochrome c release, and down-regulated of Akt activation in DLD-1 and RKO cells in a dose-dependent manner. Treatment of the DLD-1 and RKO cells with the endomorphin-2 analog increased the expression of Bax and reduced the expression of Bcl-2.ConclusionsEndomorphin-2 analog inhibited colon cancer cell proliferation, activated apoptosis, and down-regulated Akt phosphorylation of human DLD-1 and RKO colon cancer cells in vitro in a dose-dependent manner.

Pimozide suppresses cancer cell migration and tumor metastasis through binding to ARPC2, a subunit of the Arp2/3 complex.

ARPC2 is a subunit of the Arp2/3 complex, which is essential for lamellipodia, invadopodia and filopodia, and ARPC2 has been identified as a migrastatic target molecule. To identify ARPC2 inhibitors, we generated an ARPC2 knockout DLD‐1 human colon cancer cell line using the clustered regularly interspaced short palindromic repeats/CRISPR‐associated protein 9 (CRISPR/Cas9) system and explored gene signature‐based strategies, such as a connectivity map (CMap) using the gene expression profiling data of ARPC2 knockout and knockdown cells. From the CMap‐based drug discovery strategy, we identified pimozide (a clinically used antipsychotic drug) as a migrastatic drug and ARPC2 inhibitor. Pimozide inhibited the migration and invasion of various cancer cells. Through drug affinity responsive target stability (DARTS) analysis and cellular thermal shift assay (CETSA), it was confirmed that pimozide directly binds to ARPC2. Pimozide increased the lag phase of Arp2/3 complex‐dependent actin polymerization and inhibited the vinculin‐mediated recruitment of ARPC2 to focal adhesions in cancer cells. To validate the likely binding of pimozide to ARPC2, mutant cells, including ARPC2F225A, ARPC2F247A and ARPC2Y250F cells, were prepared using ARPC2 knockout cells prepared by gene‐editing technology. Pimozide strongly inhibited the migration of mutant cells because the mutated ARPC2 likely has a larger binding pocket than the wild‐type ARPC2. Therefore, pimozide is a potential ARPC2 inhibitor, and ARPC2 is a new molecular target. Taken together, the results of the present study provide new insights into the molecular mechanism and target that are responsible for the antitumor and antimetastatic activity of pimozide.

Abstract 1663: Identification and characterization of a small-molecule inhibitor of the human uracil-DNA glycosylase for use in combination with DNA damage-based anticancer therapies

Abstract Our research aims to develop therapeutically active inhibitors of the human uracil-DNA glycosylase (UNG). UNG, a highly conserved enzyme, plays a pivotal role in preventing abnormal bases, uracil and 5-fluorouracil, from incorporation into DNA as a result of treatment with chemotherapeutic drugs, floxuridine (5-FdU) and pemetrexed (PEM). Our previous publication reports that the depletion of UNG by shRNA causes uracil and 5-FU incorporation into DNA following 5-FdU or PEM exposure, and highly sensitizes certain human cancer cells to these chemotherapeutic drugs. These data suggest that UNG specific inhibitors could improve the anticancer effect of 5-FdU or PEM. However, a few known inhibitors have not been shown to function at therapeutic concentrations in human cells. Therefore, in order to identify a novel, small-molecule compound targeting the human UNG enzymatic activity, we have previously optimized a biochemically high-throughput screening (HTS) assay that measures the removal of uracil from a DNA hairpin based on the un-quenching of fluorescence. This assay has been successfully employed in a pharmacologically active compound collection screen (&amp;gt;3,000 small-molecules+ approved drugs). In 384-well plate runs using control wells in which enzyme is not added, the average assay provides signal to background ratios of 3.0 to 4.0. Typical Z factors range from 0.6-0.7, indicating a robust assay. We have identified five bioactive compounds with IC50 values &amp;lt; 1uM and have selected a nanoMolar inhibitor of the human UNG enzyme termed, UNGi-A. By using an in vitro DNA glycosylase activity assay, this compound displays a significant inhibitory activity towards the purified human UNG enzyme over time, in a dose-dependent manner. Further characterization shows a significant effect of this inhibitor on UNG activity in cellular extract that expresses endogenous UNG from DLD1 human colon cancer cell line. The result suggests that UNGi-A compound diminishes UNG activity in cell extracts. In addition, thermal shift assay (TSA) data suggest that UNGi-A binds directly to the human UNG enzyme. Together, this compound shows potential activity that blocks the human UNG activity and we are currently evaluating the effect of UNGi-A in combination with 5-FdU on UNG activity in human cancer cells. Citation Format: Mya T. Nguyen, Yan Yan, Yuriy Fedorvo, John Pink, Drew Adams, Stanton Gerson. Identification and characterization of a small-molecule inhibitor of the human uracil-DNA glycosylase for use in combination with DNA damage-based anticancer therapies [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 1663.

Quantitative proteomic and phosphoproteomic comparison of human colon cancer DLD-1 cells differing in ploidy and chromosome stability.

Although aneuploidy is poorly tolerated during embryogenesis, aneuploidy and whole chromosomal instability (CIN) are common hallmarks of cancer, raising the question of how cancer cells can thrive in spite of chromosome aberrations. Here we present a comprehensive and quantitative proteomics analysis of isogenic DLD-1 colorectal adenocarcinoma cells lines, aimed at identifying cellular responses to changes in ploidy and/or CIN. Specifically, we compared diploid (2N) and tetraploid (4N) cells with posttetraploid aneuploid (PTA) clones and engineered trisomic clones. Our study provides a comparative data set on the proteomes and phosphoproteomes of the above cell lines, comprising several thousand proteins and phosphopeptides. In comparison to the parental 2N line, we observed changes in proteins associated with stress responses and with interferon signaling. Although we did not detect a conspicuous protein signature associated with CIN, we observed many changes in phosphopeptides that relate to fundamental cellular processes, including mitotic progression and spindle function. Most importantly, we found that most changes detectable in PTA cells were already present in the 4N progenitor line. This suggests that activation of mitotic pathways through hyper-phosphorylation likely constitutes an important response to chromosomal burden. In line with this conclusion, cells with extensive chromosome gains showed differential sensitivity toward a number of inhibitors targeting cell cycle kinases, suggesting that the efficacy of anti-mitotic drugs may depend on the karyotype of cancer cells.

Yellow and green pigments from Calophyllum inophyllum L. seed oil induce cell death in colon and lung cancer cells.

Natural compounds have been candidates for anticancer medicine over the last 20 years. During the process of isolating seed oil from Calophyllum inophyllum L., yellow and green pigments containing multiple compounds with an aromatic structure were identified. High-performance liquid chromatography and nuclear magnetic resonance analysis of these pigments revealed that the compounds present were identical, but the concentration of the compounds was different. Treatment with the pigments was able to induce the death of DLD-1 human colon cancer cells and increase the percentage of the cells in the sub-G1 and sub-G2/M phases in a dose-dependent manner. Additionally, the pigments were able to exhibit cytotoxic activity on A549 and H1975 human non-small cell lung cancer (NSCLC) cell lines at 24 h, with half-maximal inhibitory concentrations (IC50) values of 0.1206 and 0.0676%, respectively for green pigments, and 0.0434 and 0.0501%, respectively for yellow pigments. Furthermore, a decrease in IC50 value was associated with an increase in the duration of treatment. However, a sharp decrease in IC50 value of the yellow pigment was observed for H1975 cells at 48 h and for A549 cells at 72 h compared with no change in IC50 value for the green pigment with time, suggesting that the pigments function and induce cell death differently in the two cell lines. An investigation was performed into the synergistic effect of the green pigment and gefitinib (Iressa®, ZD1839), which is a selective epidermal growth factor receptor-tyrosine kinase inhibitor to block growth factor-mediated cell proliferation. The combination of the green pigment and gefitinib resulted in an enhancement of the decrease in viability of A549 and H1975 cells compared with treatment with gefitinib alone, which suggested that treatment with the green pigments was able to enhance the sensitivity of NSCLC cells to gefitinib. In conclusion, these pigments may be considered for development as anti-colon cancer agents.

Sensitive and Label-Free Fluorescent Detection of Transcription Factors Based on DNA-Ag Nanoclusters Molecular Beacons and Exonuclease III-Assisted Signal Amplification.

Transcription factors (TFs) regulate gene expression by binding to regulatory regions, and their dysregulation is involved in numerous diseases. Thus, they are therapeutic targets and potential diagnostic markers. However, widely used methods for TFs detection are either cumbersome or costly. Herein, we first applied DNA-Ag nanoclusters molecular beacons (AgMBs) in TFs analysis and designed an assay based on the switchable fluorescence of AgMBs. In the absence of TFs, a single-stranded DNA functioned as a reporter is released from a double-stranded DNA probe (referred as dsTFs probe) under exonuclease III (Exo III) digestion. Then, the reporter triggers downstream Exo III-assisted signal amplification by continuously consuming the guanine-rich enhancer sequences in AgMBs, resulting in significant fluorescent decrease eventually. Conversely, the presence of TFs protects the dsTFs probe from digestion and blocks the downstream reaction to keep a highly fluorescent state. To testify this rationale, we utilized nuclear factor-kappa B p50 (NF-κB p50) as a model TFs. Owing to the amplification strategy, this method exhibited high sensitivity toward NF-κB p50 with a limit of detection of 10 pM, and a broad linear range from 30 pM to 1.5 nM. Furthermore, this method could detect multiple TFs in human colon cancer DLD-1 cells and reflect the variation in their cellular levels after stimulation. Finally, by conducting an inhibition assay we revealed the potential of this method for screening TFs-targeted drugs and calculating the IC50 of corresponding inhibitors.

Lawsone suppresses azoxymethane mediated colon cancer in rats and reduces proliferation of DLD-1 cells via NF-κB pathway.

Lawsone (LS) a colored napthoquinone compound obtained from the plant Lawsonia inermis L. (Lythraceae) is known for its usefulness of being a precursor for synthesis of some anticancer compounds. Literatures support potent anticancer activity of napthoquinone derivatives in human colon cancer, present study evaluates the effect and mechanism of LS on chemical induced colon cancerous rats and human colon cancer DLD-1 cells, the study was supported by endoscopy, histological and immunohistochemistry analysis. KAD rats were subjected to colon cancer mediated by Azoxymethane (AOM) injections followed Dextran sodium sulfate (DSS) orally in drinking water. After endoscopic confirmation the rats were given LS (200mg/ml) orally for 8 weeks. Presence of aberrant foci, types of tumors and the proliferative effect on tumor lesions was studied by macroscopic, histological and immunohistochemical analysis. To establish the mechanism, human colon DLD-1 cancer cells were exposed to LS and its effect on proliferation were studied. LS reduced aberrant crypt without affecting tumor pathology. Histological study of colon suggested decrease in numbers of adenomas and lesions. Immunohistochemistry confirmed the antiproliferative activity in adenocarcinomas without affecting the cells of normal colon mucosa. Results on human DLD-1 cells showed LS delayed progression of cell cycle by decreasing expression of cyclin B1 as well as cdk1 by inactivating NF-κB without inducing apoptosis. The study concluded role of LS in suppressing cell proliferation of colon tumors. The suppressive activity on DLD-1 cells was not by apoptosis but by decreased NF-κB activity resulting in suppression of expression levels of cyclin B1 and cdk1.

Snail1 expression in human colon cancer DLD-1 cells confers invasive properties without N-cadherin expression

The epithelial-mesenchymal transition (EMT) is a fundamental characteristic of carcinoma cells. EMT is generally associated with a change in cellular morphology from cobblestone to spindle shape, reduced expression of epithelial markers such as E-cadherin, and enhanced expression of mesenchymal markers such as N-cadherin. This EMT-associated reciprocal expression of E-cadherin and N-cadherin has been called the “cadherin switch”. Downregulation of E-cadherin enables cells to dissociate from colonies while upregulation of N-cadherin is associated with increased invasiveness. The transcription factor Snail1 induces these changes in various epithelial cell lines, including canine MDCK cells and human A431 cells. In the present study, we introduced a Snail1 expression vector into human DLD-1 cells and isolated stable transfectants. These cells showed changes in morphology, reduced expression of epithelial marker E-cadherin and occludin, and elevated invasion and migration. However, neither expression of N-cadherin protein nor its corresponding mRNA was detected. Therefore, elevated N-cadherin expression is not required for invasiveness of the cells.

Adapalene inhibits the activity of cyclin-dependent kinase 2 in colorectal carcinoma.

Cyclin-dependent kinase 2 (CDK2) has been reported to be overexpressed in human colorectal cancer; it is responsible for the G1-to-S-phase transition in the cell cycle and its deregulation is a hallmark of cancer. The present study was the first to use idock, a free and open-source protein-ligand docking software developed by our group, to identify potential CDK2 inhibitors from 4,311 US Food and Drug Administration-approved small molecular drugs with a re-purposing strategy. Among the top compounds identified by idock score, nine were selected for further study. Among them, adapalene (ADA; CD271,6-[3-(1-adamantyl)-4-methoxyphenyl]-2-naphtoic acid) exhibited the highest anti-proliferative effects in LoVo and DLD1 human colon cancer cell lines. Consistent with the expected properties of CDK2 inhibitors, the present study demonstrated that ADA significantly increased the G1-phase population and decreased the expression of CDK2, cyclin E and retinoblastoma protein (Rb), as well as the phosphorylation of CDK2 (on Thr-160) and Rb (on Ser-795). Furthermore, the anti-cancer effects of ADA were examined in vivo on xenograft tumors derived from DLD1 human colorectal cancer cells subcutaneously inoculated in BALB/C nude mice. ADA (20 mg/kg orally) exhibited marked anti-tumor activity, comparable to that of oxaliplatin (40 mg/kg), and dose-dependently inhibited tumor growth (P<0.05), while combined administration of ADA and oxaliplatin produced the highest therapeutic effect. To the best of our knowledge, the present study was the first to indicate that ADA inhibits CDK2 and is a potential candidate drug for the treatment of human colorectal cancer.