Comparative toxicological analysis of two pristine carbon nanomaterials (graphene oxide and aminated graphene oxide) and their corresponding degraded forms using human in vitro models

Despite the wide application of graphene-based materials, the information of the toxicity associated to some specific derivatives such as aminated graphene oxide is scarce. Likewise, most of these studies analyse the pristine materials, while the available data regarding the harmful effects of degraded forms is very limited. In this work, the toxicity of graphene oxide (GO), aminated graphene oxide (GO-NH2), and their respective degraded forms (dGO and dGO-NH2) obtained after being submitted to high-intensity sonication was evaluated applying in vitro assays in different models of human exposure. Viability and ROS assays were performed on A549 and HT29 cells, while their skin irritation potential was tested on a reconstructed human epidermis model. The obtained results showed that GO-NH2 and dGO-NH2 substantially decrease cell viability in the lung and gastrointestinal models, being this reduction slightly higher in the cells exposed to the degraded forms. In contrast, this parameter was not affected by GO and dGO which, conversely, showed the ability to induce higher levels of ROS than the pristine and degraded aminated forms. Furthermore, none of the materials is skin irritant. Altogether, these results provide new insights about the potential harmful effects of the selected graphene-based nanomaterials in comparison with their degraded counterparts.

Solid self-microemulsifying drug delivery system (S-SMEDDS) prepared by spray drying to improve the oral bioavailability of cinnamaldehyde (CA)

The aim of this study was to prepare a solid self-microemulsifying drug delivery system (S-SMEDDS) of cinnamaldehyde (CA) by spray drying technique to improve the oral bioavailability of CA. The preparation of CA S-SMEDDS with maltodextrin as the solid carrier, a core-wall material mass ratio of 1:1, a solid content of 20% (w/v), an inlet air temperature of 150 °C, an injection speed of 5.2 mL/min, and an atomization pressure of 0.1 MPa was determined by using the encapsulation rate as the index of investigation. Differential scanning calorimetry (DSC) revealed the possibility of CA being encapsulated in S-SMEDDS in an amorphous form. The in-vitro release showed that the total amount of CA released by S-SMEDDS was approximately 1.3 times higher than that of the CA suspension. Pharmacokinetic results showed that the relative oral bioavailability of CA S-SMEDDS was also increased to 1.6-fold compared to CA suspension. Additionally, we explored the mechanism of CA uptake and transport of lipid-soluble drugs CA by S-SMEDDS in a Caco-2/HT29 cell co-culture system for the first time. The results showed that CA S-SMEDDS uptake on the co-culture model was mainly an energy-dependent endocytosis mechanism, including lattice protein-mediated endocytosis and vesicle-mediated endocytosis. Transport experiments showed that CA S-SMEDDS significantly increased the permeability of CA in this model. These findings suggested that CA S-SMEDDS is an effective oral solid dosage form for increasing the oral bioavailability of lipid-soluble drug CA.

Xanthones from Gentianella acuta (Michx.) Hulten Ameliorate Colorectal Carcinoma via the PI3K/Akt/mTOR Signaling Pathway

Colorectal carcinoma (CRC) is a kind of malignant tumor closely related to ulcerative colitis. Xanthone derivatives are one of the most promising therapeutic drugs which have been used in phase I/II clinical trials for cancer therapy. Our previous study indicated that the aerial parts of Gentianella acuta Michx. Hulten (GA) was rich in xanthones and showed a good therapeutic effect on ulcerative colitis in mice, suggesting that GA xanthones might have some therapeutic or ameliorative effects on CRC. However, no relevant study has been reported. This study aims to find the effective substances of GA inhibiting CRC and clarify their mechanism. Solvent extraction, column chromatographic separation, and LC-MS analysis were used to characterize the 70% EtOH extract of GA and track xanthones abundant fraction XF. MTT assay was carried out to clarify the activity of GA fractions; the result showed XF to be the main active fraction. LC-MS analysis was executed to characterize XF, 38 xanthones were identified. Network pharmacology prediction, in vitro activity screening, and molecular docking assay were combined to predict the potential mechanism; the PI3K/Akt/mTOR signaling pathway was found to be most important. Western blot assay on the main active xanthones 1,3,5-trihydroxyxanthone (16), 1,3,5,8-tetrahydroxyxanthone (17), 1,5,8-trihydroxy-3-methoxyxanthone (18), and 1,7-dihydroxy-3,8-dimethoxyxanthone (19) was used to verify the above prediction; these xanthones were found to inhibit the PI3K/Akt/mTOR signaling pathway, and 17 played a significant role among them through Western blot assay using PI3K/AKT/mTOR agonist IGF-1. In conclusion, this study demonstrated that GA xanthones were effective compounds of GA inhibiting CRC by regulating PI3K/Akt/mTOR signaling pathway transduction, at least. Importantly, 1,3,5,8-tetrahydroxyxanthone (17), the most abundant active xanthone in GA, might be a candidate drug for CRC.

Loss of NKCC1 function increases epithelial tight junction permeability by upregulating claudin-2 expression

Conditions that cause the loss of epithelial barrier integrity are often accompanied by dysregulation of tight junction protein expression and/or localization. Recently, we have reported that patients with mutations in SLC12A2, the gene encoding the basolateral Na+-K+-2Cl- cotransporter (NKCC1), suffer from severe gastrointestinal deficits, including chronic gastrointestinal inflammation, gastrointestinal hemorrhage, intestinal obstruction, and constipation. Although the intestinal inflammation observed in patients with loss of NKCC1 function may or may not be due to tight junction dysfunction, we investigated whether the loss of NKCC1 function affects paracellular ion transport and epithelial barrier function. Wild-type HT29-MTX-E12 and CRISPR/Cas9-mediated NKCC1 knockout (KO) HT29 clones were tested for tight junction protein expression and localization. Tightness of epithelial cell monolayer was assessed by measurement of transepithelial electrical resistance and permeability of molecular tracers in transwell filters. Tight junction protein localization was assessed by immunofluorescence. Loss of NKCC1 expression strongly increases the expression of claudin-2 and occludin in epithelial cell monolayers. Loss of NKCC1 significantly reduces the transepithelial electrical resistance (TER) indicating an increase in paracellular ions flux, consistent with upregulation of the cation-selective and channel-forming claudin-2. In addition, NKCC1-KO monolayers showed a significant increase in the paracellular flux of small molecules like fluorescein (0.33 kDa), whereas the permeability of higher molecular weight TRITC-Dextran (4 kDa and 70 kDa) remained unchanged. Thus, NKCC1 regulates tight junction protein expression and loss of NKCC1 function affects epithelial barrier integrity.

Toosendanin inhibits colorectal cancer cell growth through the Hedgehog pathway by targeting Shh

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers worldwide. This complex and often fatal disease has a high mortality rate. The Hedgehog (Hh) signaling pathway is crucial in CRC. Many studies have indicated that Shh is overexpressed in cancer stem cells (CSCs), and shh overexpression is positively correlated with CRC tumorigenesis. New drugs that kill CRC cells through the Hh pathway are needed. Toosendanin (TSN), a natural triterpenoid saponin extracted from the bark or fruit of Melia toosendan Sieb. et Zucc, can inhibit various tumors. Here, we investigated the effects of TSN in CRC and explored the possible targets and mechanisms. Shh-Light Ⅱ cells were treated with TSN and tested by dual luciferase reporter assays to determine the relationship with the Hh pathway. Cell Counting Kit-8 (CCK-8) assays were used to test the inhibitory effects of TSN on CRC cells. The expression of Hh components after TSN treatment was detected using western blots and quantitative reverse transcription polymerase chain reaction. Cellular thermal shift assays confirmed the targets of TSN. The same effects of TSN on xenograft tumor growth were investigated in vivo. The average weight, volume of the finally resected tumor, and the expression of Shh in the TSN-treated groups were significantly lower than those of the control group. This result strongly suggested that TSN administration inhibited CRC growth in vivo. Our research preliminarily demonstrated that the target of TSN was Shh and that TSN inhibits CRC cell growth by inhibiting the Hh pathway, identifying a new anticancer molecular mechanism of TSN in CRC.

The Class I HDAC Inhibitor, MS-275, Prevents Oxaliplatin-Induced Chronic Neuropathy and Potentiates Its Antiproliferative Activity in Mice

Oxaliplatin, the first-line chemotherapeutic agent against colorectal cancer (CRC), induces peripheral neuropathies, which can lead to dose limitation and treatment discontinuation. Downregulation of potassium channels, which involves histone deacetylase (HDAC) activity, has been identified as an important tuner of acute oxaliplatin-induced hypersensitivity. MS-275, a class I histone deacetylase inhibitor (HDACi), prevents acute oxaliplatin-induced peripheral neuropathy (OIPN). Moreover, MS-275 exerts anti-tumor activity in several types of cancers, including CRC. We thus hypothesized that MS-275 could exert both a preventive effect against OIPN and potentially a synergistic effect combined with oxaliplatin against CRC development. We first used RNAseq to assess transcriptional changes occurring in DRG neurons from mice treated by repeated injection of oxaliplatin. Moreover, we assessed the effects of MS-275 on chronic oxaliplatin-induced peripheral neuropathy development in vivo on APC^Min/+ mice and on cancer progression when combined with oxaliplatin, both in vivo on APC^Min/+ mice and in a mouse model of an orthotopic allograft of the CT26 cell line as well as in vitro in T84 and HT29 human CRC cell lines. We found 741 differentially expressed genes (DEGs) between oxaliplatin- and vehicle-treated animals. While acute OIPN is known as a channelopathy involving HDAC activity, chronic OIPN exerts weak ion channel transcriptional changes and no HDAC expression changes in peripheral neurons from OIPN mice. However, MS-275 prevents the development of sensory neuropathic symptoms induced by repeated oxaliplatin administration in APC^Min/+ mice. Moreover, combined with oxaliplatin, MS-275 also exerts synergistic antiproliferative and increased survival effects in CT26-bearing mice. Consistently, combined drug associations exert synergic apoptotic and cell death effects in both T84 and HT29 human CRC cell lines. Our results strongly suggest combining oxaliplatin and MS-275 administration in CRC patients in order to potentiate the antiproliferative action of chemotherapy, while preventing its neurotoxic effect.

Synthesis of Silver Nanoparticles from the Polysaccharide of Farfarae Flos and Uncovering Its Anticancer Mechanism Based on the Cell Metabolomic Approach

In this study, the polysaccharide of Farfarae Flos (FFP) was utilized as a reducing agent to the green synthesis of FFP@AgNPs, and the anticancer activity was evaluated using the HT29 cells. The results showed that the FFP@AgNPs could significantly decrease proliferation ability, inhibit migration, and promote cell apoptosis of HT29 cells, which suggested that the FFP@AgNPs showed significant, strong cytotoxicity against HT29 cells. The cell metabolomic analysis coupled with the heatmap showed an obvious metabolome difference for the cells with and without FFP@AgNPs treatment, which was related to 51 differential metabolites. Four metabolic pathways were determined as the key pathways, and the representative functional metabolites and metabolic pathways were validated in vitro. Nicotinic acid (NA) was revealed as the key metabolite relating with the effect of FFP@AgNPs, and it was interesting that NA supplementation could inhibit the proliferation ability of HT29 cells in vitro, lead to mitochondrial dysfunction, reduce intracellular ATP, and damage the integrity of the cell membrane, which exhibited a similar effect as FFP@AgNPs. In conclusion, this study not only revealed the anticancer mechanism of FFP@AgNPs against the HT29 cells but also provided the important reference that NA shows a potential role in the development of a therapy for colorectal cancer.

Combination of resveratrol and BIBR1532 inhibits proliferation of colon cancer cells by repressing expression of LncRNAs

Colorectal cancer (CRC) is the third most common cancer worldwide. The development of tumor drug resistance is observed in the treatment of CRC. Combinations of anticancer agents are attracting considerable interest in order to overcome drug resistance in CRC. This study aims to investigate the effect of resveratrol and BIBR1532, either alone or in combination, on the cell viability as well as on expression of long non-coding RNAs (LncRNAs) for HT-29 colon adenocarcinoma cells. The cytotoxic effects of resveratrol and BIBR1532 on HT-29 cells were determined using WST-1 test. Flow cytometry was used to determine apoptotic cell death after treatments. Real-Time PCR was used to identify expression of LncRNAs after treatments. LncExpDB and GEPIA2 were used to evaluate expression profiles of LncRNAs, whose expression levels were decreased in HT-29 cells after treatments, in normal tissues and colon adenocarcinoma tumors. IC₅₀ concentrations of BIBR1532 and resveratrol were found to be 50.81 μM at 48 h and 86.23 μM at 72 h, respectively. Combination index value was 1.07617. BIBR1532, resveratrol, or their combination reduced the cell viability of HT-29 cells. CCAT1, CRNDE, HOTAIR, PCAT1, PVT1, SNHG16 were down-regulated after treatments. In silico analysis revealed that LncRNAs whose expression levels were decreased after treatments were associated with CRC. Resveratrol, BIBR1532, or their combination may have anti-proliferative effect on colorectal cancer cells through repressing expression of LncRNAs that are involved in progression of CRC.

The Effect and Potential Mechanism of microRNA-124 on the Biological Behavior of Colon Cancer Cells

OBJECTIVE

We aimed to investigate the expression of microRNA-124 (miR-124) in colon cancer and its biological function in colon cancer cells as well as its underlying mechanism.

METHODS

Mimic miR-124 and unrelated sequence were transfected into colon cancer HT29 cells, and a blank control group was established with untreated HT29 cells. The expression of miR-124 in each group was detected by qRT-PCR. CCK-8 assay, cell scratch assay, Transwell assay, and flow cytometry were used to detect the effects of miR-124 on cell growth, invasion, migration, and apoptosis in HT29 cells. The expression of TET protein family and related protein was evaluated by Western blot.

RESULTS

miR-124 expression was significantly downregulated in colon cancer HT29 cells (P<0.05). Overexpressed miR-124 suppressed cell proliferation, migration, and invasion, and it promoted the apoptosis of HT29 cells. The significantly increased expression of TET family protein and the reduction of vimentin and MMP2 expression were seen in miR-124-transfected HT29 cells (all P<0.05).

CONCLUSION

The expression of miR-124 inhibited cell proliferation, suppressed tumor cell migration and invasion, and enhanced apoptosis by its regulation of the expression of TET1, TET2, vimentin, and MMP-2 in colon cancer HT29 cells.

Antiproliferative Effect of Colonic Fermented Phenolic Compounds from Jaboticaba (Myrciaria trunciflora) Fruit Peel in a 3D Cell Model of Colorectal Cancer

Jaboticaba is a Brazilian native berry described as a rich source of phenolic compounds (PC) with health promoting effects. PC from jaboticaba peel powder (JPP) have low intestinal bio-accessibility and are catabolized by gut microbiota. However, the biological implication of PC-derived metabolites produced during JPP digestion remains unclear. This study aimed to evaluate the antiproliferative effects of colonic fermented JPP (FJPP) in a 3D model of colorectal cancer (CRC) composed by HT29 spheroids. JPP samples fermented with human feces during 0, 2, 8, 24 or 48 h were incubated (10,000 µg mL⁻¹) with spheroids, and cell viability was assessed after 72 h. Chemometric analyses (cluster and principal component analyses) were used to identify the main compounds responsible for the bioactive effect. The antiproliferative effect of FJPP in the CRC 3D model was increased between 8 h and 24 h of incubation, and this effect was associated with HHDP-digalloylglucose isomer and dihydroxyphenyl-γ-valerolactone. At 48 h of fermentation, the antiproliferative effect of FJPP was negligible, indicating that the presence of urolithins did not improve the bioactivity of JPP. These findings provide relevant knowledge on the role of colonic microbiota fermentation to generate active phenolic metabolites from JPP with positive impact on CRC.

The combination of lactoferrin and linolenic acid inhibits colorectal tumor growth through activating AMPK/JNK-related apoptosis pathway

Colorectal cancer is a common cause of death with few available therapeutic strategies, and the preventative complexes in adjunctive therapy are urgently needed. Increasing evidences have shown that natural ingredients, including lactoferrin, oleic acid, docosahexaenoic acid (DHA) and linolenic acid, possess anti-inflammatory and anti-tumor activities. However, investigations and comparisons of their combinations in colorectal tumor model have not been reported, and the mechanism is still unrevealed. In the study, we examined the viability, migration, invasion and apoptosis of HT29 cells to choose the proper doses of these components and to select the effective combination in vitro. BALB/c nude mice bearing colorectal tumor were used to explore the role of selected combination in inhibiting tumor development in vivo. Additionally, metabonomic detection was performed to screen out the specific changed metabolitesand related pathway. The results demonstrated that lactoferrin at 6.25 μM, oleic acid at 0.18 mM, DHA at 0.18 mM, and linolenic acid at 0.15 mM significantly inhibited the viabilities of HT29 cells (p < 0.05). The combination of lactoferrin (6.25 μM) + linolenic acid (0.15 mM) exhibited the strongest activity in inhibiting the migration and invasion of HT29 cells in vivo and suppressing tumor development in vitro (p < 0.05). Furthermore, the lactoferrin + linolenic acid combination activated p-AMPK and p-JNK, thereby inducing apoptosis of HT29 cells (p < 0.05). The present study was the first to show that lactoferrin + linolenic acid combination inhibited HT29 tumor formation by activating AMPK/JNK related pathway.

Polymeric Nanovectors Incorporated with Ganciclovir and HSV-tk Encoding Plasmid for Gene-Directed Enzyme Prodrug Therapy

In the area of gene-directed enzyme prodrug therapy (GDEPT), using herpes simplex virus thymidine kinase (HSV-tk) paired with prodrug ganciclovir (GCV) for cancer treatment has been extensively studied. It is a process involved with two steps whereby the gene (HSV-tk) is first delivered to malignant cells. Afterward, non-toxic GCV is administered to that site and activated to cytotoxic ganciclovir triphosphate by HSV-tk enzyme expressed exogenously. In this study, we presented a one-step approach that both gene and prodrug were delivered at the same time by incorporating them with polymeric micellar nanovectors. GCV was employed as an initiator in the ring-opening polymerization of ε-caprolactone (ε-CL) to synthesize hydrophobic GCV-poly(caprolactone) (GCV-PCL), which was furthered grafted with hydrophilic chitosan to obtain amphiphilic polymer (GCV-PCL-chitosan) for the fabrication of self-assembled micellar nanoparticles. The synthesized amphiphilic polymer was characterized using Fourier transform infrared spectroscopy and proton nuclear magnetic resonance. Micellar prodrug nanoparticles were analyzed by dynamic light scattering, zeta potential, critical micelle concentration, and transmission electron microscopy. Polymeric prodrug micelles with optimal features incorporated with HSV-tk encoding plasmids were cultivated with HT29 colorectal cancer cells and anticancer effectiveness was determined. Our results showed that prodrug GCV and HSV-tk cDNA encoded plasmid incorporated in GCV-PCL-chitosan polymeric nanocarriers could be delivered in a one-step manner to HT-29 cells and triggered high cytotoxicity.

β-sitosterol Mediated Silver Nanoparticles Induce Cytotoxicity in Human Colon Cancer HT-29 Cells

Background:

Silver nanoparticles (AgNP) are commonly used metallic nanoparticles in health care systems. Colon cancer incidence is increasing worldwide. In this study, AgNP was synthesized using β-sitosterol and its cytotoxic potential was evaluated in human colon cancer (HT-29) cells.

Methods:

Characterization of AgNP was analyzed by TEM and spectrophotometry analysis. HT-29 cells were treated with different concentrations (2, 4, 6, 8 and 10 ng/ml) of AgNPs and cytotoxicity was evaluated by MTT assay. The apoptosis was analyzed by the flow cytometry. The expression of p53 protein was analyzed by western blotting.

Results:

β-sitosterol mediated AgNP are spherical in shape and induced concentration-dependent cytotoxicity in HT-29 cells. AgNP caused apoptosis related morphological changes as evidenced by annexin positive staining. AgNP treatments also induced the p53 expression in HT-29 cells.

Conclusion:

Our present result suggests that β-sitosterol mediated AgNP induce apoptosis in colon cancer cells and this finding may pave the way for further experimental analysis in vivo.

Uncovering the Effect of Passage Number on HT29 Cell Line Based on the Cell Metabolomic Approach

The passage number is an important factor when designing the cell line-based experiment. Although HT29 cells were widely used in the laboratory for colorectal cancer studies, the impact of cell passage number on the HT29 cells was still unknown. In this study, phenotypic assay and metabolomic approach were applied to analyze the systemic effects of passage numbers (passage 4, 10, and 16) on the HT29 cells. The results showed that the increased cell passage number affected the cell cycle distribution and also decreased the proliferation and migration ability of HT29 cells. The metabolomic analysis coupled with heatmap and hierarchical cluster analysis showed obvious metabolome difference among the cells with different passage numbers, which was related with 61 differential metabolites. Three metabolic pathways were determined as the key pathways, and arginine participated in two of them. In addition, it was found that arginine supplementation could inhibit the proliferation ability of HT29 cells in vitro, and a synergistic effect existed between arginine and cisplatin. In conclusion, this study not only revealed the influence of passage numbers on the HT29 cell but also provided an important reference that arginine has the potential role to be developed as the cisplatin therapeutic adjuvant.

LPS Enhances the Chemosensitivity of Oxaliplatin in HT29 Cells via GSDMD-Mediated Pyroptosis

Introduction

Pyroptosis induced by lipopolysaccharide (LPS) is a dissolved form of cell death. The molecular marker gasdermin D, specifically GSDMD-N, is critically required for the induction of pyroptosis. Recently, there have been studies showing that LPS is closely related to tumor biology.

Methods

Specimens from 40 patients with colorectal cancer (CRC) were collected. Eight- to twelve-week-old C57BL6 male mice (n=30) were raised. Immunohistochemistry and Western blot were performed to test the expression of GSDMD. Moreover, cytotoxicity assay, IL-18 and IL-1β ELISA, Annexin V and PI stain, and wound healing assay were also made. Gene Expression Profiling Interactive Analysis (GEPIA) was used to verify the expression of GSDMD and overall survival of CRC patients with a high/low expression of GSDMD.

Results

In the research, we showed that the poor prognosis in CRC patients was significantly related to the GSDMD expression and significantly down-regulated in human colorectal cancer (CRC) tissues. Treatment with LPS, but not TNF-α, induced pyroptosis via promoting the expression of GSDMD and GSDMD-N membrane translocation and enhanced chemosensitivity in response to L-OHP in HT29 cells. Furthermore, the enforced expression of GSDMD in HT29 cells reduced cell survival and induced cell death.

Discussion

These results of studies suggest that the low expression of GSDMD correlates with a poor CRC prognosis, and that pyroptosis induced by LPS may improve the anti-cancer effect of L-OHP, inhibiting the tumorigenesis of CRC by activating GSDMD. Our findings lay the foundation for further development of GSDMD serving as an important prognostic biomarker and a valid CRC therapeutic target.

SiRNA targeting PFK1 inhibits proliferation and migration and enhances radiosensitivity by suppressing glycolysis in colorectal cancer

PURPOSE

This study explored the effects of phosphofructokinase-1 (PFK1) on the radiosensitivity of colorectal cancer (CRC) in vivo and in vitro and the underlying mechanisms.

METHODS

Tissue samples from 48 patients with rectal cancer who had received neoadjuvant radiotherapy followed by surgery were analyzed. The expression of PFK1 in tissue samples was semi-quantitated by immunohistochemistry, and its relationship with clinicopathological features was analyzed. The effects of PFK1 knockdown on the survival, apoptosis, migration, and radiosensitivity of CRC cells were evaluated. Glycolysis-related indicators were used to examine glycolytic activity. The effects of PFK1 on the radiosensitivity of CRC in vivo were assessed by measuring tumor formation in nude mice.

RESULTS

PFK1 was overexpressed in rectal cancer and was higher in radiation-resistant tumors than in radiation-sensitive tumors. SiRNA-induced PFK1 silencing increased apoptosis and inhibited migration and proliferation of CRC cells. Knockdown of PFK1 made the CRC cells sensitive to ionizing radiation in vivo. Oligomycin partially restored the expression of PFK1, enhanced glycolysis, and reversed the enhanced radiosensitivity of CRC cells induced by siRNA-PFK1. Downregulation of PFK1 combined with irradiation inhibited growth of nude mice xenografts, which was related to an increase in apoptosis.

CONCLUSIONS

Our study indicates that high expression of PFK1 is negatively correlated with radiosensitivity in CRC and likely accelerates the proliferation and migration of CRC cells. Downregulation of PFK1 may enhance the radiosensitivity of CRC cells in vivo and in vitro by inhibiting glycolysis.

Luteolin induces mitochondrial apoptosis in HT29 cells by inhibiting the Nrf2/ARE signaling pathway

The aim of the current study was to investigate luteolin-induced apoptosis and the molecular mechanisms underlying it in HT29 cells. A 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay was used to assess the cytotoxicity of luteolin on HT29 cells, and a dichloro-dihydro-fluorescein diacetate assay was used to measure cellular levels of reactive oxygen species (ROS). The effects of luteolin on the mitochondrial membrane potential were also evaluated. Bax and Bcl-2 mRNA expression were determined using reverse transcription-quantitative PCR. Additionally, western blot analysis was performed to assess changes in cytochrome c and caspase-3 protein expression. Localization of nuclear factor erythroid 2-related factor 2 (Nrf2) in the nucleus was also assessed using immunofluorescence. Luteolin exhibited cytotoxicity on HT29 cells in a time- and concentration-dependent manner. Additionally, ROS production was indicated to be increased and ROS scavenging was decreased, which resulted in a significant increase in the levels of ROS in the cells. The mitochondrial membrane potential was indicated to decrease following luteolin treatment. At the molecular level, luteolin significantly increased the mRNA expression of Bax and the protein expression of cytochrome c, caspase-3, p47phox and p22phox. The results revealed that luteolin decreased Bcl-2 protein expression and inhibited the nuclear localization of Nrf2. In conclusion, the current study indicated that luteolin inhibited HT29 cell proliferation and induced apoptosis via the mitochondrial pathway.

Indomethacin and juglone inhibit inflammatory molecules to induce apoptosis in colon cancer cells

Colorectal cancer (CRC) is the third most common fatal cancer. Indomethacin, a nonsteroidal anti-inflammatory drug, is known to reduce the occurrence of CRC. This study evaluated the potential anticolon cancer effects of juglone (5-hydroxy-1,4-naphthoquinone) in combination with indomethacin. Human colon adenocarcinoma cells (HT29) were subjected to treatment with indomethacin, juglone, and a combination of both. Morphological analysis, cell cycle regulation, and dual staining using acridine orange and ethidium bromide in control and treated cells revealed the apoptotic potential of these compounds. Bcl2 and inflammatory molecules (tumor necrosis factor-α, nuclear factor kappa B, and Cox-2) were found to be decreased with a concomitant increase in the expression of proapoptotic molecules (Bad, Bax, cytochrome c, and PUMA) as a result of the molecular regulation of Wnt, Notch, and peroxisome proliferator-activated receptor-γ signaling. Treatment with juglone was not as effective as with indomethacin; however, a combination of both was shown to be more effective, suggesting that juglone may be considered for therapeutic intervention of colon cancer.

Astragalus Polysaccharides Protects Thapsigargin-induced Endoplasmic Reticulum Stress in HT29 Cells

Aim

This study investigates the effect of astragalus polysaccharides (APS) in protecting against thapsigargin-induced endoplasmic reticulum (ER) stress in HT29 cells by suppressing the PERK-eIF2a signaling pathway.

Methods

HT29 cells were induced by thapsigargin for 12 hours, then treated with APS for 24 hours, and the gene expressions of GRP78, CHOP and eIF2a were quantified by reverse transcription quantitative polymerase chain reaction (RT-qPCR). The expression of GRP78, CHOP, PERK, p-PERK, eIF2a, and p-eIF2a were detected by Western blot.

Results

The ER stress caused by thapsigargin strongly up-regulated the expression of GRP78 and CHOP in HT29 cells, which activated the PERK-eIF2a pathway. There was an increase in PERK phosphorylation, and induction of eIF2a in HT29 cells. Thapsigargin caused significant ER expansion in HT29 cells due to the 12-hour ER stress. Importantly, Astragalus polysaccharide significantly inhibited the phosphorylation of PERK and eIF2a, which reduced the mRNA levels of GRP78, CHOP, PERK and eIF2a, and inhibited the ER expansion in HT29 cells after 24 hours of treatment.

Conclusion

The results indicate that APS reduces the expression of GRP78 and CHOP in HT29 cells, at least in part, by preventing the activation of the PERK-eIF2a signaling pathway.

Antiproliferative, neurotoxic, genotoxic and mutagenic effects of toxic cyanobacterial extracts

Cyanobacteria are the rich resource of various secondary metabolites including toxins with broad pharmaceutical significance. The aim of this work was to evaluate the antiproliferative, neurotoxic, genotoxic and mutagenic effects of cyanobacterial extracts containing Microcystin-LR (MCLR) in vitro. ELISA analysis results showed that MCLR contents of five cyanobacterial extracts were 2.07 ng/mL, 1.43 ng/mL, 1.41 ng/mL, 1.27 ng/mL, and 1.12 ng/mL for Leptolyngbya sp. SB1, Phormidium sp. SB4, Oscillatoria earlei SB5, Phormidium sp. SB2, Uncultured cyanobacterium, respectively. Phormidium sp. SB4 and Phormidium sp. SB2 extracts had the lowest neurotoxicity (86% and 79% cell viability, respectively) and Oscillatoria earlei SB5 extracts had the highest neurotoxicity (47% cell viability) on PC12 cell at 1000 µg/ml extract concentration. Leptolyngbya sp. SB1 and Phormidium sp. SB2 showed the highest antiproliferative effect (92% and 77% cell death) on HT29 cell. On the other hand, all concentrations of five toxic cyanobacterial extracts induced DNA damage between 3.0% and 1.3% of tail intensity and did not cause any direct mutagenic effect at the 1000 µg/plate cyanobacterial extracts. These results suggest that cyanobacteria-derived MCLR is a promising candidate for development of effective agents against colon cancer.

Toxicological assessment of magnesium oxide nanoparticles in HT29 intestinal cells

Nanoparticles (NPs) are increasingly used in different consumer-related areas, for instance in food packaging or as additives, because of their enormous potential. Magnesium oxide (MgO) is an EU-approved food additive (E number 530). It is commonly used as a drying agent for powdered foods, for colour retention or as a food supplement. There are no consistent results regarding the effects of oral MgO NP uptake. Consequently, the aim of this study was to examine the effects of MgO NPs in the HT29 intestinal cell line. MgO NP concentrations ranged from 0.001 to 100 μg/ml and incubation times were up to 24 h. The cytotoxic and genotoxic potential were investigated. Apoptotic processes and cell cycle changes were analysed by flow cytometry. Finally, oxidative stress was examined. Transmission electron microscopy indicated that there was no cellular uptake. MgO NPs had no cytotoxic or genotoxic effects in HT29 cells and they did not induce apoptotic processes, cell cycle changes or oxidative stress.

Real-time monitoring of HT29 epithelial cells as an in vitro model for assessing functional differences among intestinal microbiotas from different human population groups

Several in vitro screening tests have been used for selecting probiotic strains; however they often show low predictive value and only a limited number of strains have demonstrated functionality in vivo. The most used in vitro tests represent a very simplified version of the gut environment, especially since they do not consider the accompanying microbiota. Therefore, there is a need to develop sensitive and discriminating in vitro models including the microbiota. Here we developed an in vitro model to discriminate among microbiotas/fecal waters from different population groups. To this end samples were obtained from seven healthy adults, five IBD-patients, ten full-term and ten preterm newborns. Fecal microbiotas were purified and their impact, as well as that of the fecal waters, on HT29 cells was continuously monitored for 22 h using a real-time cell analyzer (RTCA). The composition of the purified microbiotas was assessed by 16S rRNA gene profiling and qPCR and the levels of short chain fatty acids (SCFA) determined by gas chromatography. The microbiota fractions and SCFA concentrations obtained from IBD-patients, full-term and preterm babies, showed clear differences with regard to those of the control group (healthy adults). Moreover, the purified intestinal microbiotas and fecal waters also differed from the control group in the response induced on the HT29 cells assay developed. In short, we have developed a real-time, impedance-based in vitro model for assessing the functional response induced by purified microbiotas and fecal waters upon intestinal epithelial cells. The capability of the assay for discriminating the functional responses induced, by microbiotas or fecal waters from different human groups, promises to be of help on the search for compounds/strains to restore the functionality of the microbiota-host's interaction.

Exploring the usefulness of the complex in vitro intestinal epithelial model Caco-2/HT29/Raji-B in nanotoxicology

The use of in vitro barrier models is gaining relevance as an alternative to animal studies in risk assessment, pharmacokinetic, and toxicological studies in general. These models permit an easier evaluation of the underlying mechanisms taking place at the molecular and cellular levels on the barrier site. Here, we report several methodological modifications of the three-dimensional in vitro intestinal epithelial model Caco-2/HT29/Raji-B for its successful application in the Nanotoxicology field. In addition, new insights in the study of specific molecular markers and new confocal microscope approaches have also been incorporated. Due to the multiple variables and parameters playing a part when the model's complexity is increased, we have monitored the barrier's formation and cell differentiation over time. Finally, the practical usability of the proposed model was tested by evaluating the action of the food additives titanium dioxide and silica dioxide nanoparticles (TiO₂NPs and SiO₂NPs). The NPs-associated effects were evaluated by confocal microscopy. We have demonstrated the essential role of the mucus layer in the decrease of cellular uptake, avoiding potential NPs-cell nuclei interactions.

Quantitative assessment of specific carbonic anhydrase inhibitors effect on hypoxic cells using electrical impedance assays

Carbonic anhydrase IX (CA IX) is an important orchestrator of hypoxic tumour environment, associated with tumour progression, high incidence of metastasis and poor response to therapy. Due to its tumour specificity and involvement in associated pathological processes: tumourigenesis, angiogenesis, inhibiting CA IX enzymatic activity has become a valid therapeutic option. Dynamic cell-based biosensing platforms can complement cell-free and end-point analyses and supports the process of design and selection of potent and selective inhibitors. In this context, we assess the effectiveness of recently emerged CA IX inhibitors (sulphonamides and sulphocoumarins) and their antitumour potential using an electrical impedance spectroscopy biosensing platform. The analysis allows discriminating between the inhibitory capacities of the compounds and their inhibition mechanisms. Microscopy and biochemical assays complemented the analysis and validated impedance findings establishing a powerful biosensing tool for the evaluation of carbonic anhydrase inhibitors potency, effective for the screening and design of anticancer pharmacological agents.

Treatment mechanism of matrine in combination with irinotecan for colon cancer

The inhibitory effect of matrine (MA) was studied in combination with irinotecan (CPT-11) on proliferation of human colon carcinoma cell line HT29. We also explored the mechanism of cell apoptosis induction in HT29. HT29 cells were treated with different concentrations of MA and CPT-11 alone and in combination. The growth inhibition in HT29 cells was evaluated using MTT assay. Apoptosis was detected using AV-PI double staining flow cytometry. Transmission electron microscopy was used to detect structural changes in cells. Topoisomerase (TOPO) I, Bax and Caspase-3 expression levels were evaluated using western blot analysis. MA and CPT-11 alone and in combination, inhibited the proliferation of HT29 cells, whereas the combination treatment exhibited higher inhibitory effect (P<0.01). This suggests the existence of synergistic cytotoxicity. Compared with each treatment alone, the combination treatment caused more significant damage to cell structure, and caused a significantly higher apoptosis rate (P<0.01). Additionally, the combination treatment increased TOPO I, Bax and Caspase-3 expression levels (P<0.01). In conclusion, MA in combination with CPT-11 synergistically inhibited HT29 cell proliferation and induced apoptosis in these cells. The mechanism may be related to upregulation of the TOPO I, Bax and Caspase-3 protein expression.

Pectic oligosaccharide structure-function relationships: Prebiotics, inhibitors of Escherichia coli O157:H7 adhesion and reduction of Shiga toxin cytotoxicity in HT29 cells

Shiga toxin (Stx)-producing, food-contaminating Escherichia coli (STEC) is a major health concern. Plant-derived pectin and pectic-oligosaccharides (POS) have been considered as prebiotics and for the protection of humans from Stx. Of five structurally different citrus pectic samples, POS1, POS2 and modified citrus pectin 1 (MCP1) were bifidogenic with similar fermentabilities in human faecal cultures and arabinose-rich POS2 had the greatest prebiotic potential. Pectic oligosaccharides also enhanced lactobacilli growth during mixed batch faecal fermentation. We demonstrated that all pectic substrates were anti-adhesive for E. coli O157:H7 binding to human HT29 cells. Lower molecular weight and deesterification enhanced the anti-adhesive activity. We showed that all pectic samples reduced Stx2 cytotoxicity in HT29 cells, as measured by the reduction of human rRNA depurination detected by our novel TaqMan-based RT-qPCR assay, with POS1 performing the best. POS1 competes with Stx2 binding to the Gb3 receptor based on ELISA results, underlining the POS anti-STEC properties.

Bacillus megaterium SF185 induces stress pathways and affects the cell cycle distribution of human intestinal epithelial cells

The interaction between the enteric microbiota and intestinal cells often involves signal molecules that affect both microbial behaviour and host responses. Examples of such signal molecules are the molecules secreted by bacteria that induce quorum sensing mechanisms in the producing microorganism and signal transduction pathways in the host cells. The pentapeptide competence and sporulation factor (CSF) of Bacillus subtilis is a well characterized quorum sensing factor that controls competence and spore formation in the producing bacterium and induces cytoprotective heat shock proteins in intestinal epithelial cells. We analysed several Bacillus strains isolated from human ileal biopsies of healthy volunteers and observed that some of them were unable to produce CSF but still able to act in a CSF-like fashion on model intestinal epithelial cells. One of those strains belonging to the Bacillus megaterium species secreted at least two factors with effects on intestinal HT29 cells: a peptide smaller than 3 kDa able to induce heat shock protein 27 (hsp27) and p38-MAPK, and a larger molecule able to induce protein kinase B (PKB/Akt) with a pro-proliferative effect.

Photophysical Characterization and in Vitro Phototoxicity Evaluation of 5,10,15,20-Tetra(quinolin-2-yl)porphyrin as a Potential Sensitizer for Photodynamic Therapy

Photodynamic therapy (PDT) is a selective and minimally invasive therapeutic approach, involving the combination of a light-sensitive compound, called a photosensitizer (PS), visible light and molecular oxygen. The interaction of these per se harmless agents results in the production of reactive species. This triggers a series of cellular events that culminate in the selective destruction of cancer cells, inside which the photosensitizer preferentially accumulates. The search for ideal PDT photosensitizers has been a very active field of research, with a special focus on porphyrins and porphyrin-related macrocycle molecules. The present study describes the photophysical characterization and in vitro phototoxicity evaluation of 5,10,15,20-tetra(quinolin-2-yl)porphyrin (2-TQP) as a potential PDT photosensitizer. Molar absorption coefficients were determined from the corresponding absorption spectrum, the fluorescence quantum yield was calculated using 5,10,15,20-tetraphenylporphyrin (TPP) as a standard and the quantum yield of singlet oxygen generation was determined by direct phosphorescence measurements. Toxicity evaluations (in the presence and absence of irradiation) were performed against HT29 colorectal adenocarcinoma cancer cells. The results from this preliminary study show that the hydrophobic 2-TQP fulfills several critical requirements for a good PDT photosensitizer, namely a high quantum yield of singlet oxygen generation (Φ∆ 0.62), absence of dark toxicity and significant in vitro phototoxicity for concentrations in the micromolar range.

Cytotoxicity and physicochemical characterization of iron-manganese-doped sulfated zirconia nanoparticles

Iron-manganese-doped sulfated zirconia nanoparticles with both Lewis and Brønsted acidic sites were prepared by a hydrothermal impregnation method followed by calcination at 650°C for 5 hours, and their cytotoxicity properties against cancer cell lines were determined. The characterization was carried out using X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, Brauner-Emmett-Teller (BET) surface area measurements, X-ray fluorescence, X-ray photoelectron spectroscopy, zeta size potential, and transmission electron microscopy (TEM). The cytotoxicity of iron-manganese-doped sulfated zirconia nanoparticles was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays against three human cancer cell lines (breast cancer MDA-MB231 cells, colon carcinoma HT29 cells, and hepatocellular carcinoma HepG2 cells) and two normal human cell lines (normal hepatocyte Chang cells and normal human umbilical vein endothelial cells [HUVECs]). The results suggest for the first time that iron-manganese-doped sulfated zirconia nanoparticles are cytotoxic to MDA-MB231 and HepG2 cancer cells but have less toxicity to HT29 and normal cells at concentrations from 7.8 μg/mL to 500 μg/mL. The morphology of the treated cells was also studied, and the results supported those from the cytotoxicity study in that the nanoparticle-treated HepG2 and MDA-MB231 cells had more dramatic changes in cell morphology than the HT29 cells. In this manner, this study provides the first evidence that iron-manganese-doped sulfated zirconia nanoparticles should be further studied for a wide range of cancer applications without detrimental effects on healthy cell functions.

Molecular mechanism of anticancer effect of Sclerotium rolfsii lectin in HT29 cells involves differential expression of genes associated with multiple signaling pathways: A microarray analysis

Sclerotium rolfsii lectin (SRL) is a lectin isolated from fungus S. rolfsii and has high binding specificity toward the oncofetal Thomsen-Friedenreich carbohydrate antigen (Galβ1-3GalNAc-α-O-Ser/Thr, T or TF), which is expressed in more than 90% of human cancers. Our previous studies have shown that binding of SRL to human colon, breast and ovarian cancer cells induces cell apoptosis in vitro and suppresses tumor growth in vivo. This study investigated the SRL-mediated cell signaling in human colon cancer HT29 cells by mRNA and miRNA microarrays. It was found that SRL treatment results in altered expression of several hundred molecules including mitogen-activated protein kinase (MAPK) and c-JUN-associated, apoptosis-associated and cell cycle and DNA replication-associated signaling molecules. Pathway analysis using GeneSpring 12.6.1 revealed that SRL treatment induces changes of MAPK and c-JUN-associated signaling pathways as early as 2 h while changes of cell cycle, DNA replication and apoptosis pathways were significantly affected only after 24 h. A significant change of cell miRNA expression was also observed after 12 h treatment of the cells with SRL. These changes were further validated by quantitative real time polymerase chain reaction and immunoblotting. This study thus suggests that the presence of SRL affects multiple signaling pathways in cancer cells with early effects on cell proliferation pathways associated with MAPK and c-JUN, followed by miRNA-associated cell activity and apoptosis. This provides insight information into the molecular mechanism of the anticancer activity of this fungal lectin.

Backscattered electron SEM imaging of cells and determination of the information depth

Backscattered electron imaging of HT29 colon carcinoma cells in a scanning electron microscope was studied. Thin cell sections were placed on indium-tin-oxide-coated glass slides, which is a promising substrate material for correlative light and electron microscopy. The ultrastructure of HT29 colon carcinoma cells was imaged without poststaining by exploiting the high chemical sensitivity of backscattered electrons. Optimum primary electron energies for backscattered electron imaging were determined which depend on the section thickness. Charging effects in the vicinity of the SiO₂ nanoparticles contained in cell sections could be clarified by placing cell sections on different substrates. Moreover, a method is presented for information depth determination of backscattered electrons which is based on the imaging of subsurface nanoparticles embedded by the cells.

Vitamin C modulates DNA damage induced by hydrogen peroxide in human colorectal adenocarcinoma cell lines (HT29) estimated by comet assay in vitro

INTRODUCTION

Cancer cells, compared to normal cells, are under increased oxidative stress associated with oncogenic transformation, alterations in metabolic activity, and increased generation of reactive oxygen species.

MATERIAL AND METHODS

We investigated the ability of vitamin C to reduce the damage induced by hydrogen peroxide, in human colorectal adenocarcinoma cells in vitro by the comet assay. Additionally, we measured the kinetics and efficacy of the repair of DNA damage after incubation with vitamin C in the presence of H2O2.

RESULTS

The obtained results showed that 1 h pre-incubation with vitamin C and exposure to H2O2 for the last 10 min of incubation caused a statistically significant (p < 0.05) increase in DNA migration in comet tails in all experimental series. For the 10 µM, 25 µM, 50 µM, 100 µM vitamin C concentrations the levels of DNA damage were as follows: 18.6%, 21.1%, 25.3% and 27.2%, respectively, as compared to the untreated cells (3.26%). However, in comparison with H2O2 alone (29.1%), we observed a statistically significant (p < 0.05) decrease of the genotoxic effect in HT29 cells induced by H2O2 for the two lowest of concentrations of vitamin C: 10 µM and 25 µM. The HT29 cells were able to achieve effective repair of the damaged DNA within 60 and 120 min after incubation with the tested compounds. All the values obtained in the test were statistically significant (p < 0.05).

CONCLUSIONS

Vitamin C caused a weaker DNA damaging effect of hydrogen peroxide and positively influences the level of oxidative DNA damage in HT29 cells (decrease ∼ 30%). We noted that DNA damage was effectively repaired during 120 min postincubation in the tested cells and that oxidative damage was the major type of damage.

Deficiency in the 15 kDa selenoprotein inhibits human colon cancer cell growth

Selenium is an essential micronutrient for humans and animals, and is thought to provide protection against some forms of cancer. These protective effects appear to be mediated, at least in part, through selenium-containing proteins (selenoproteins). Recent studies in a mouse colon cancer cell line have shown that the 15 kDa selenoprotein (Sep15) may also play a role in promoting colon cancer. The current study investigated whether the effects of reversing the cancer phenotype observed when Sep15 was removed in mouse colon cancer cells, were recapitulated in HCT116 and HT29 human colorectal carcinoma cells. Targeted down-regulation of Sep15 using RNAi technology in these human colon cancer cell lines resulted in similarly decreased growth under anchorage-dependent and anchorage-independent conditions. However, the magnitude of reduction in cell growth was much less than in the mouse colon cancer cell line investigated previously. Furthermore, changes in cell cycle distribution were observed, indicating a delayed release of Sep15 deficient cells from the G(0)/G(1) phase after synchronization. The potential mechanism by which human colon cancer cells lacking Sep15 revert their cancer phenotype will need to be explored further.

Gene expression profiles in human peripheral blood mononuclear cells as biomarkers for nutritional in vitro and in vivo investigations

Identification of chemopreventive substances may be achieved by measuring biological endpoints in human cells in vitro. Since generally only tumour cells are available for such investigations, our aim was to test the applicability of peripheral blood mononuclear cells (PBMC) as an in vitro primary cell model since they mimic the human in vivo situation and are relatively easily available. Cell culture conditions were refined, and the basal variation of gene expression related to drug metabolism and stress response was determined. Results were compared with profiles of an established human colon cell line (HT29) as standard. For biomarker development of nutritional effects, PBMC and HT29 cells were treated with potentially chemopreventive substances (chrysin and butyrate), and gene expression was determined. Key results were that relevant stress response genes, such as glutathione S-transferase T2 (GSTT2) and GSTM2, were modulated by butyrate in PBMC as in HT29 cells, but the blood cells were less sensitive and responded with high individual differences. We conclude that these cells may serve as a surrogate tissue in dietary investigations and the identified differentially expressed genes have the potential to become marker genes for population studies on biological effects.

In vitro and in vivo anti-colorectal carcinoma activities of Zuojin Pill and its major constituents

AIM: To investigate the intervention effect of Zuojin Pill and its major constituents against colorectal carcinoma in vitro and in vivo.

METHODS: Cultured HT29 cells in the logarithmic growth phase were treated with berberine (26.25, 52.5, 105, 210 and 420 μmol/L, respectively) and evodiamine (5, 10, 15, 20, 25 and 30 μmol/L, respectively) for 24, 48, 72 and 96 h, respectively, to determine the optimal concentration and duration of treatment. Under optimal conditions, the inhibitory effects of berberine and evodiamine on the proliferation of HT29 cells were examined by a viable cell count method, and the telomerase activity of the treated cells was determined by the TRAP method. The single cell suspension of HT29 cells was then prepared and subcutaneously injected into the left abdominal region of nude mice at a concentration of 5×10⁵ cells/0.2 mL to produce tumor-bearing nude mice. These mice were randomly divided into four groups, namely, control group (injection with saline), Zuojin Pill group, AZT (Azidothymidine) group and Zuojin Pill plus AZT group. The effects of Zuojin Pill and AZT on tumor growth and telomerase activity were observed. Additionally, a rat model of colorectal carcinoma was induced with 1, 2-dimethyl hydrazine (DMH). The rats were also randomly divided into four groups, treated in the same manner as described above, and killed at weeks 11, 21 and 34, respectively, to observe the effects of Zuojin Pill and AZT against the progression of rat colorectal carcinoma.

RESULTS: Evodiamine and berberine dose-dependently inhibited the proliferation of HT29 cells in vitro. The suppression ratios achieved using evodiamine (7.5, 15 and 30 μmol/L, respectively) were 39.3% ± 2.13%, 52.8% ± 5.34% and 64.1% ± 7.19%, respectively, while those achieved using berberine (52.5, 105, 210 μmol/L) were 44.1% ± 3.97%, 55.9% ± 4.12% and 65.3% ± 6.94%, respectively. Moreover, berberine and evodiamine could effectively inhibit the telomerase activity of HT29 cells. In tumor-bearing nude mice, Zuojin Pill and AZT had no significant influence on tumor size but had weak effect on telomerase activity. In DMH-induced rat colon cancer model, the tumor incidences observed at week 11 in the control group, Zuojin Pill group, AZT group and Zuojin Pill plus group were 20%, 0%, 10% and 10%, respectively. In contrast, the tumor incidences at week 34 showed no significant difference among different groups.

CONCLUSION: The major constituents of Zuojin Pill can suppress the proliferation and telomerase activity of HT29 cells in vitro. In DMH-produced rat model, Zuojin Pill can effectively repress the development and progression of early-stage carcinoma, but has no obvious effect against late-stage carcinoma.