Sulindac sulfide inhibits the proliferation of colon cancer cells: diminished expression of the proliferation markers PCNA and Ki-67

Panlongqi tablet suppresses adjuvant-induced rheumatoid arthritis by inhibiting the inflammatory reponse in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Panlongqi Tablet is prepared with the ancestral secret recipe provided by Mr. Wang Jiacheng, a famous specialist in orthopedics and traumatology of China. The efficacy and safety of PLQT have been supported by years of clinical practice in the treatment of joint-related conditions. Has remarkable effect for treating rheumatoid arthritis (RA) clinically. However, its mechanism is not entirely clear.

AIM OF THE STUDY

We aim to evaluate the anti-inflammatory activity of PLQT and explore its mechanism in adjuvant-induced arthritis (AA) mice and LPS-induced Human fibroblast-like synovial (HFLS) cells.

MATERIALS AND METHODS

To this end, we analyzed the active ingredients in PLQT by HPLC-MS/MS. Furthermore, the anti-RA effect of PLQT was studied through proliferation, apoptosis, foot swelling, cytokine levels, immune organ index, histopathology and related signal pathways in LPS-induced HFLS cells and AA-treated mice.

RESULTS

HPLC-MS/MS results showed that PLQT contained a variety of active compounds, such as epicatechin, imperatorin, hydroxysafflor yellow A and so on. PLQT significantly inhibited the abnormal proliferation of HFLS cells induced by LPS, promoted cell apoptosis. In AA-treated mice, PLQT alleviated RA symptoms by alleviating paw swelling, synovial hyperplasia, pannus formation, inflammatory cell infiltration, and inhibiting abnormal immune responses. The results showed that PLQT significantly decreased the expression of inflammatory mediators (IL-1β, IL-6, IL-17) in vivo and in vitro, which may be related to the regulation of PI3K/Akt, MAPK and JAK/STAT signaling pathways.

CONCLUSION

Based on serum pharmacology and in vivo pharmacology studies, PLQT may regulate RA symptoms by regulating inflammatory and immune response-related pathways, which is an effective method for the treatment of RA.

The Effect of Low Doses of Acetylsalicylic Acid on the Occurrence of Rectal Aberrant Crypt Foci

Background and Objectives: Aberrant crypt foci (ACF) are one of the earliest putative preneoplastic and, in some cases, neoplastic lesions in human colons. Many studies have confirmed the reduction of ACFs and colorectal adenomas after treatment with acetylsalicylic acid (ASA) commonly referred to as ASA; however, the minimum effective dose of ASA and the duration of use has not been fully elucidated. The objective of our study was to assess the significance of low dose ASA (75-mg internally once daily) to study the chemopreventive effect of ASA in ACF and adenomas development in patients taking this drug for a minimum period of 10 years. Materials and Methods: Colonoscopy, combined with rectal mucosa staining with 0.25% methylene blue, was performed on 131 patients. The number of rectal ACF in the colon was divided into three groups: ACF < 5; ACF 5−10; and ACF > 10. Patients were divided into two groups: the “With ASA” group (the study group subjects taking ASA 75-mg daily for 10 years); and “Without ASA” group (control group subjects not taking ASA chronically). The incidence of different types of rectal ACF and colorectal polyps in both groups of subjects was analysed and ascertained. Results: Normal ACF was found in 12.3% in the study group vs. 87.7% control group, hyperplastic 22.4% vs. 77.6%, dysplastic 25% vs. 75%, mixed 0% vs. 100%. Treatment with ASA affects the occurrence of colorectal adenomas. The amount of dysplastic ACFs was lower in the study group than in the control group. The increase in dysplastic ACFs decreases with age in both groups, with the increase greater in those not taking ASA. Conclusions: Patients who take persistent, chronic (>10 years) low doses of ASA have a lower total number of all types of rectal ACFs and adenomas compared to the control group.

Anti-Inflammatory Food in Asthma Prepared from Combination of Raphanus sativus L., Allium hookeri, Acanthopanax sessiliflorum, and Dendropanax morbiferus Extracts via Bioassay-Guided Selection

Asthma is a highly prevalent inflammatory disease of the respiratory airways and an increasing health risk worldwide. Hence, finding new strategies to control or attenuate this condition is necessary. This study suggests nutraceuticals that are a combination of herbal plant extracts prepared from Acanthopanax sessiliflorum (AS), Codonopsis lanceolate (CL), Dendropanax morbiferus (DM), Allium hookeri (AH), and Raphanus sativus L. (RS) that can improve immunomodulatory ability through the detoxification and diuresis of air pollutants. Herbal parts (AH whole plant, RS and CL roots, AS and DM stems, and DM leaves) were selected, and four types of mixtures using plant extracts were prepared. Among these mixtures, M2 and M4 exhibited antioxidant activities in potent 2,2-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) and 1,1-diphenyl-β-picrylhydrazine (DPPH) radical assays. Moreover, M4 exhibited a marked increase in glutathione S-transferase (GST) activity and significantly inhibited the inflammatory mediator, nitric oxide (NO) and proinflammatory cytokines, interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α generation. Furthermore, M4 exhibited the strongest antioxidant, hepatoprotective, and anti-inflammatory effects and was selected to prepare the product. Before manufacturing the product, we determined that the active mixture, M4, inhibited gene expression and generation of proinflammatory cytokines IL-1β, IL-6 and TNF-α in ovalbumin (OVA)-, lipopolysaccharide (LPS)-, and particulate matter (PM)-induced asthmatic rat models. The granular product (GP) was manufactured using M4 along with additives, i.e., lactose, oligosaccharide, stevioside extract, and nutmeg seed essential oils (flavor masking), in a ratio of 1:4 using a granulation machine, dried and ultimately packaged. The GP inhibited the generation of proinflammatory cytokines IL-1β, IL-6 and TNF-α in OVA-, LPS- and PM-induced asthmatic rat models. These results suggest that GP prepared from a combination of herbal plants (AS, CL, DM, AH and RS) is a potent functional food with anti-inflammatory activity that can be used to treat asthma caused by ambient air pollutants.

Upregulated lncRNA Cyclin-dependent kinase inhibitor 2B antisense RNA 1 induces the proliferation and migration of colorectal cancer by miR-378b/CAPRIN2 axis

LncRNA Cyclin‐dependent kinase inhibitor 2B antisense RNA 1 (CDKN2B-AS1) plays a role in the progression of multiple cancers like cholangiocarcinoma, osteosarcoma and several gastrointestinal tumors. Few studies have linked its function and mechanism to the development of colorectal cancer (CRC). The expression of CDKN2B-AS1, microRNA (miR)-378b, and cytoplasmic activation/proliferation-associated protein 2 (CAPRIN2) was analyzed in CRC patients and cell lines. The proliferation and migration of CRC cells were evaluated after gain and loss-of function mutations. Interactions between CDKN2B-AS1 and miR-378b, miR-378b and CAPRIN2 were validated by luciferase reporter, RNA pull-down and RNA immunoprecipitation assays. The role of CDKN2B-AS1 was further confirmed in a xenograft mouse model. We found that the expression of CDKN2B-AS1 and CAPRIN2 was upregulated in CRC and they were linked to the poor differentiation and distant metastasis in CRC patients. CDKN2B-AS1 knockdown attenuated while CDKN2B-AS1 overexpression promoted CRC cell proliferation and migration. Notably, the results of Starbase 2.0 database analysis and in vitro experiments demonstrated that CDKN2B-AS1 could interact with miR-378b and regulate its expression. Furthermore, CAPRIN2 acted as a downstream target of CDKN2B-AS1/miR-378b that involved in modulating β-catenin expression in CRC cells. Upregulation of CDKN2B-AS1 contributed to CRC progression via regulating CAPRIN2 expression by binding to miR-378b. Downregulation of CDKN2B-AS1 suppressed tumor growth and Ki-67 staining in vivo that was related to the miR-378b/CAPRIN2 pathway. This study indicated that lncRNA CDKN2B-AS1 promoted the development of CRC through the miR-378b/CAPRIN2/β-catenin axis. CDKN2B-AS1 might serve as a potential and useful target in CRC diagnosis and treatment.

Chemopreventive efficacy of juniper berry oil (Juniperus communis L.) on azoxymethane-induced colon carcinogenesis in rat

The aim of this study was to investigate the chemopreventive effects of juniper berry (JB) oil on azoxymethane (AOM)-induced colon cancer in rats. Thirty-two male Wistar albino rats were allocated into four groups: Control, AOM, AOM + JB, and JB groups. Whereas the control group was fed with standard pellet feed, the AOM and AOM + JB groups were administered of AOM (15 mg/kg body weight) subcutaneously once every 2 weeks for 10 weeks. AOM + JB and JB groups additionally received JB oil (100 µl/kg) orally. At the end of the 16-week experimental period, blood and tissue samples were obtained from the rats following necropsy. The macroscopic findings showed that the application of JB oil significantly decreased adenoma and adenocarcinoma formation both numerically and dimensionally. Immunohistochemically, CEA, COX-2, and Ki-67 immune-expressions decreased, and the immune-expression of caspase-3 increased in AOM + JB treated rats. Additionally, JB oil supplementation ameliorated antioxidant defense systems and lipid peroxidation within the colon tissue of AOM + JB treated rats. These results reveal that the JB oil acted as a chemopreventive dietary agent, inhibiting cell proliferation and COX-2 expression and inducing apoptosis, resulting in a significant reduction in colon tumor formation.

Upregulated expression of MNX1-AS1 long noncoding RNA predicts poor prognosis in gastric cancer

As important regulators of gene expression long noncoding RNAs (lncRNAs) are implicated in various physiological and pathological processes, including cancer. An oncogenic role of MNX1 antisense RNA 1 (MNX1-AS1) lncRNA has been suggested in cervical cancer and glioblastoma. In this study, we investigated the clinicopathological significance and biological function of MNX1-AS1 in gastric cancer (GC). The expression of MNX1-AS1 was analyzed by qRT-PCR in 96 GC and adjacent non-tumor tissues in relation to clinicopathological features and overall survival (OS) of patients, and in five human GC cell lines compared to a normal gastric epithelial cell line. Loss-of-function experiments using small interfering RNA (siRNA) targeting MNX1-AS1 (si-MNX1-AS1) were carried out in AGS and MGC-803 GC cell lines. Cell proliferation (CCK-8 assay), migration (Transwell) and invasion (Transwell Matrigel), and protein expression of proliferating cell nuclear antigen (PCNA), E-cadherin, N-cadherin, vimentin and matrix metallopeptidase 9 (MMP-9) were analyzed in transfected GC cells. Expression of MNX1-AS1 was significantly higher in GC vs. adjacent non-tumor tissues. Higher MNX1-AS1 expression was significantly associated with tumor size, TNM stage and lymph node metastasis. Kaplan-Meier analysis showed that GC patients with higher MNX1-AS1 expression had worse OS compared to patients with lower MNX1-AS1 expression. Multivariate analysis showed that MNX1-AS1 is an independent poor prognostic factor in GC. Knockdown of MNX1-AS1 significantly inhibited proliferation, migration and invasion of AGS and MGC-803 cells, and resulted in increased E-cadherin and decreased PCNA, N-cadherin, vimentin and MMP-9 expression. Taken together, these results suggest that MNX1-AS1 has an oncogenic function in GC and potential as a molecular target in GC therapy.

Wnt-beta-catenin pathway signals metastasis-associated tumor cell phenotypes in triple negative breast cancers

Tumor cells acquire metastasis-associated (MA) phenotypes following genetic alterations in them which cause deregulation of different signaling pathways. Earlier, we reported that an upregulation of the Wnt-beta-catenin pathway (WP) is one of the genetic salient features of triple-negative breast cancer (TNBC), and WP signaling is associated with metastasis in TNBC. Using cBioPortal, here we found that collective % of alteration(s) in WP genes, CTNNB1, APC and DVL1 among breast-invasive-carcinomas was 21% as compared to 56% in PAM50 Basal. To understand the functional relevance of WP in the biology of heterogeneous/metastasizing TNBC cells, we undertook this comprehensive study using 15 cell lines in which we examined the role of WP in the context of integrin-dependent MA-phenotypes. Directional movement of tumor cells was observed by confocal immunofluorescence microscopy and quantitative confocal-video-microscopy while matrigel-invasion was studied by MMP7-specific casein-zymography. WntC59, XAV939, sulindac sulfide and beta-catenin siRNA (1) inhibited fibronectin-directed migration, (2) decreased podia-parameters and motility-descriptors, (3) altered filamentous-actin, (4) decreased matrigel-invasion and (5) inhibited cell proliferation as well as 3D clonogenic growth. Sulindac sulfide and beta-catenin siRNA decreased beta-catenin/active-beta-catenin and MMP7. LWnt3ACM-stimulated proliferation, clonogenicity, fibronection-directed migration and matrigel-invasion were perturbed by WP-modulators, sulindac sulfide and GDC-0941. We studied a direct involvement of WP in metastasis by stimulating brain-metastasis-specific MDA-MB231BR cells to demonstrate that LWnt3ACM-stimulated proliferation, clonogenicity and migration were blocked following sulindac sulfide, GDC-0941 and beta-catenin knockdown. We present the first evidence showing a direct functional relationship between WP activation and integrin-dependent MA-phenotypes. By proving the functional relationship between WP activation and MA-phenotypes, our data mechanistically explains (1) why different components of WP are upregulated in TNBC, (2) how WP activation is associated with metastasis and (3) how integrin-dependent MA-phenotypes can be regulated by mitigating the WP.

Brewers' rice induces apoptosis in azoxymethane-induced colon carcinogenesis in rats via suppression of cell proliferation and the Wnt signaling pathway

Background

Brewers’ rice is locally known as temukut, is a byproduct of the rice milling process, and consists of broken rice, rice bran, and rice germ. Unlike rice bran, the health benefit of brewers’ rice has yet to be fully studied. Our present study aimed to identify the chemopreventive potential of brewers’ rice with colonic tumor formation and to examine further the mechanistic action of brewers’ rice during colon carcinogenesis.

Methods

Male Sprague–Dawley rats were randomly divided into five groups: (G1) normal; (G2) azoxymethane (AOM) alone; and (G3), (G4), and (G5), which were AOM fed with 10%, 20%, and 40% (w/w) of brewers’ rice, respectively. Rats in group 2 to 5 were injected intraperitoneally with AOM (15 mg/kg body weight) once weekly for two weeks. Colon tumor incidence and multiplicity was assessed by hematoxylin and eosin (H&E) staining. The expression of β-catenin, cyclooxygenase-2 (COX-2), and Ki-67 was evaluated by immunohistochemical staining. The apoptosis-inducing activity was analyzed using a TUNEL assay. The data were analyzed using a one-way analysis of variance (ANOVA) with P-value<0.05 was considered significant.

Results

Overall analyses revealed that brewers’ rice reduced colon tumor incidence and multiplicity. The results from immunohistochemistry analysis also showed that brewers’ rice decreased the expression of β-catenin, COX-2, and Ki-67 in a dose-dependent manner. Furthermore, TUNEL analysis demonstrated that administration of brewers’ rice in AOM-induced rat colorectal cancer resulted in a dose-dependent increase in cell apoptosis.

Conclusions

Taken together, our data suggested that brewers’ rice can inhibit cell proliferation, induce apoptosis, and suppress COX-2 and β-catenin expression via the Wnt signaling pathway and holds great promise in the field of chemoprevention as a dietary agent.

Consumption of high-fat diet induces tumor progression and epithelial-mesenchymal transition of colorectal cancer in a mouse xenograft model

Epidemiologic studies suggest that intake of high-fat diet (HFD) promotes colon carcinogenesis. Epithelial-mesenchymal transition (EMT) and inflammation play important roles during tumor progression of colorectal cancer (CRC). Oncogenic pathways such as phosphatidylinositol-3-kinase (PI3K)/Akt/mTOR and mitogen-activated protein kinase (MAPK)/ERK signaling cascades induce EMT and inflammation in cancer. No experimental evidence has been demonstrated regarding HFD-mediated tumor progression including EMT in CRC so far. Our results demonstrated that HFD consumption could induce tumor growth and progression, including EMT and inflammation, in a mouse xenograft tumor model. The molecular mechanisms were through activation of MAPK/ERK and PI3K/Akt/mTOR signaling pathways. HFD induced up-regulation of cyclooxygenase-2, cyclin D1 and proliferating cell nuclear antigen proteins concomitant with increases in expression of nuclear factor-κB p65 (RelA) and β-catenin proteins. Surprisingly, HFD consumption could suppress p21(CIP1/WAF1) expression through increases in nuclear histone deacetylase complex (HDAC). Moreover, HFD could mediate the disassembly of E-cadherin adherent complex and the up-regulation of Vimentin and N-cadherin proteins in tumor tissues. Taken together, our novel findings support evidence for HFD-mediated modulation of HDAC activity and activation of oncogenic cascades, which involve EMT and inflammation in CRC, playing important roles in tumor growth and progression in a mouse xenograft model.

Effect of eicosapentaenoic acid on E-type prostaglandin synthesis and EP4 receptor signaling in human colorectal cancer cells

The omega-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA), in the free fatty acid (FFA) form, has been demonstrated to reduce adenoma number and size in patients with familial adenomatous polyposis. However, the mechanistic basis of the antineoplastic activity of EPA in the colorectum remains unclear. We tested the hypothesis that EPA-FFA negatively modulates synthesis of and signaling by prostaglandin (PG) E(2) in human colorectal cancer (CRC) cells. EPA-FFA induced apoptosis of cyclooxygenase (COX)-2-positive human HCA-7 CRC cells in vitro. EPA-FFA in cell culture medium was incorporated rapidly into phospholipid membranes of HCA-7 human CRC cells and acted as a substrate for COX-2, leading to reduced synthesis of PGE(2) and generation of PGE(3). Alone, PGE(3) bound and activated the PGE(2) EP4 receptor but with reduced affinity and efficacy compared with its "natural" ligand PGE(2). However, in the presence of PGE(2), PGE(3) acted as an antagonist of EP4 receptor-dependent 3',5' cyclic adenosine monophosphate induction in naturally EP4 receptor-positive LoVo human CRC cells and of resistance to apoptosis in HT-29-EP4 human CRC cells overexpressing the EP4 receptor. We conclude that EPA-FFA drives a COX-2-dependent "PGE(2)-to-PGE(3) switch" in human CRC cells and that PGE(3) acts as a partial agonist at the PGE(2) EP4 receptor.

Circulating Ki-67 index in plasma as a biomarker and prognostic indicator in chronic lymphocytic leukemia

Ki-67 is a nuclear antigen that is expressed in all stages of the cell cycle, except G(0), and is widely used as a marker of cellular proliferation in human tumors. We recently showed that elevated levels of Ki-67 circulating in plasma (cKi-67) are associated with shorter survival in patients with acute lymphoblastic leukemia. The current study included 194 patients with CLL and 96 healthy control subjects. cKi-67 levels in plasma were determined using an electrochemiluminescent immunoassay. We normalized the cKi-67 level to the absolute number of lymphocytes in the patient's peripheral blood to establish the plasma cKi-67 index. The cKi-67 index showed significant correlation with lymph node involvement and Rai stage (P=0.05). Higher cKi-67 index values were significantly associated with shorter survival. Multivariate Cox proportional hazards regression analysis demonstrated that the association of the cKi-67 index with shorter survival was independent of IgV(H) mutation status. In a multivariate model incorporating the cKi-67 index with B2M and IgV(H), only cKi-67 index and B2M levels remained as independent predictors of survival. The results of this study suggest that the plasma cKi-67 index, along with B2M level, is a strong predictor of clinical behavior in CLL.

Circulating Ki-67 protein in plasma as a biomarker and prognostic indicator of acute lymphoblastic leukemia

Tissue-based determination of Ki-67, a marker of cellular proliferation, has shown prognostic value in solid tumors and hematological malignancies. We developed and validated an electrochemiluminescence-based method for sensitive measurement of circulating Ki-67 in plasma (cKi-67). This assay demonstrated significantly higher levels of cKi-67 in patients with newly diagnosed acute lymphoblastic leukemia (ALL) (n=27; median, 762; range, 0-4574U/100 microL) than in healthy control subjects (n=114; median, 399; range, 36-2830U/100 microL). Moreover, elevated plasma cKi-67 was associated with significantly shorter survival in ALL patients (P=0.05). These findings suggest that Ki-67 can be detected in circulation and has potential for use as a biomarker for predicting clinical behavior in ALL.

Sulindac treatment alters collagen and matrilysin expression in adenomas of ApcMin/+ mice

Non-steroidal anti-inflammatory drugs (NSAIDs) have shown potential as chemopreventive agents against cancer formation, especially colorectal cancers. However, the mechanisms by which these drugs act are not fully understood. In this study, Apc(Min/+) mice, a genetic model of human familial adenomatous polyposis, were treated with sulindac, and these mice demonstrated tumor reduction of >80%, consistent with previous reports. Gene microarray analyses of RNA from adenoma-derived dysplastic epithelial cells revealed that collagen genes, viz. Col1a2, Col5a2, Col6a2 and Col6a3, were upregulated, and matrilysin matrix metalloproteases-7 (Mmp7) was downregulated, in sulindac-treated mice. Reverse transcription-polymerase chain reaction validated gene expression of the Col6a2 subunit of collagen VI and of Mmp7. Confocal microscopy and immunofluorescence showed that within the tumors of non-treated mice, collagen VI was present in low amounts, but was enhanced within the tumors of sulindac-treated mice. Collagens I and V demonstrated similar patterns, but were not as prominent as collagen VI. Mmp7 was found in 'hot spot' areas within the tumors of Apc(Min/+) mice treated with the vehicle, but was greatly diminished in those mice treated with sulindac. Studies with Apc(Min/+)/Mmp7(-/-) double-deficient mice demonstrated the reciprocal relationships of Mmp7 expression and the levels of these three collagens in vivo. The results of this study demonstrated that sulindac was effective in increasing the expression of different collagens and decreasing the expression of Mmp7, effects that may contribute to altered tumor burden in cancer patients undergoing NSAIDs treatments.

The role of COX-2 in intestinal cancer

Cyclooxygenase (COX), the key regulatory enzyme for prostaglandin synthesis, is transcribed from two distinct genes. COX-1 is expressed constitutively in most tissues whereas COX-2 is induced by a wide variety of stimuli and was initially identified as an immediate-early growth response gene. In addition, COX-2 expression is markedly increased in 85-90% of human colorectal adenocarcinomas while COX-1 levels remain unchanged. Several epidemiological studies have reported a 40-50% reduction in the risk of developing colorectal cancer in persons who chronically take non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, which are classic inhibitors of COX. Genetic evidence also supports a role for COX-2, since mice null for COX-2 have an 86% reduction in tumour multiplicity in a background containing a mutated APC allele. These results strongly suggest that COX-2 contributes to the development of intestinal tumours and that inhibition of COX is chemopreventative. It is hoped that the chemopreventative effects of NSAIDs will be enhanced by the recent development of COX-2-specific inhibitors.

Inhibitory effects of 7-hydroxy-3-methoxy-cadalene on 4-(methylinitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis in A/J mice

The present study was undertaken to estimate the effect of 7-hydroxy-3-methoxycadalene (cadalene) extracted from Zelkova serrata on 4-(methylinitrosamino)-1-(3-pyridyl)-1-butanone (NNK)-induced lung tumorigenesis in A/J mice. Twenty mice received orally NNK at a dose of 65 microg/ml water for 7 weeks following by free feeding of a commercial diet not containing cadalene for 2 weeks. Control group was maintained without NNK and cadalene administration and/or treatment groups with NNK and cadalene (6.25, 25, 100 mg/kg feed) feeding for 25 weeks. Lung tumors were induced by NNK at incidence ranging from 10 to 45%. Cadalene treatment (100 mg/kg feed) group significantly reduced the incidence of adenomas from 45 to 10% (P < 0.05), and other cadalene treatment group decreased cancer incidences in a concentration dependent manner. The results of our study strongly indicate that cadalene is capable of inhibiting development of NNK-induced lung tumorigenesis in A/J mice.

Effect of nonsteroidal anti-inflammatory drugs on beta-catenin protein levels and catenin-related transcription in human colorectal cancer cells

Elevated β-catenin levels in human colorectal cancer (CRC) cells lead to increased trans-activation of ‘protumorigenic’ β-catenin/T-cell factor (TCF) target genes such as cyclin D1. Therefore, possible targets for the anti-CRC activity of nonsteroidal anti-inflammatory drugs (NSAIDs) are β-catenin and catenin-related transcription (CRT). We tested the antiproliferative activity and the effects on levels of β-catenin and cyclin D1 protein, as well as CRT (measured using a synthetic β-catenin/TCF-reporter gene [TOPflash]), of a panel of NSAIDs (indomethacin, diclofenac, sulindac sulphide and sulphone, rofecoxib; range 10–600 μM) on SW480 human CRC cells in vitro. Following NSAID treatment, there was no consistent relationship between reduced cell proliferation, induction of apoptosis and changes in β-catenin protein levels or CRT. All the NSAIDs, except rofecoxib, decreased nuclear β-catenin content and cyclin D1 protein levels in parallel with their antiproliferative activity. However, cyclin D1 downregulation occurred prior to a decrease in total β-catenin protein levels and there was no correlation with changes in CRT, suggesting the existence of CRT-independent effects of NSAIDs on cyclin D1 expression. In summary, NSAIDs have differential effects on β-catenin protein and CRT, which are unlikely to fully explain their effects on cyclin D1 and their antiproliferative activity on human CRC cells in vitro.

Cyclooxygenase-2 modulates cellular growth and promotes tumorigenesis

Cyclooxygenase (COX)-2 and the prostaglandins resulting from its enzymatic activity have been shown to play a role in modulating cell growth and development of human neoplasia. Evidence includes a direct relationship between COX-2 expression and cancer incidence in humans and animal models, increased tumorigenesis after genetic manipulation of COX-2, and significant anti-tumor properties of non-steroidal anti-inflammatory drugs in animal models and in some human cancers. Recent data showed that COX-2 and the derived prostaglandins are involved in control of cellular growth, apoptosis, and signal through a group of nuclear receptors named peroxisome proliferator-activated receptors (PPARs). In this article we will review some of the findings suggesting that COX-2 is involved in multiple cellular mechanisms that lead to tumorigenesis.

Effects of low dose aspirin (81 mg) on proliferating cell nuclear antigen and Amaranthus caudatus labeling in normal-risk and high-risk human subjects for colorectal cancer

Epidemiological, experimental, and clinical observations provide support for a colorectal cancer chemopreventive role for aspirin. We have evaluated the effects of aspirin on proliferation biomarkers in normal-risk and high-risk human subjects for colorectal cancer. Colorectal biopsies were obtained at baseline and at 24h after 28 daily doses of 81 mg of aspirin from 13 high-risk and 15 normal-risk subjects for colorectal cancer. We evaluated aspirin's effects on proliferating cell nuclear antigen (PCNA) immunohistochemistry and epithelial mucin histochemistry using the lectin, Amaranthus caudatus agglutinin (ACA) in crypt sections from rectal biopsies. The baseline whole crypt PCNA LIs differed significantly between normal-risk and high-risk subjects. PCNA LIs are not affected by 28 days of aspirin at 81 mg daily. ACA LIs are decreased by 28 days of aspirin at 81 mg daily in both normal-risk and high-risk subjects. Aspirin's effects on ACA LIs may have mechanistic and biological implications that deserve further attention. PCNA and ACA LIs are not useful as proliferation biomarkers for aspirin's chemopreventive activity in morphologically normal human colorectal mucosa.

Selective induction of colon cancer cell apoptosis by 5-fluorouracil in humans

To assess the mechanism of action of 5-fluorouracil (5-FU) apoptosis (AI) and proliferation (PI) indices were determined histochemically in colon carcinoma and normal colon tissue of 7 patients treated preoperatively with 5-FU (300 mg/m2/day for 5 days) and 11 controls. 5-Fluorouracil induced apoptosis selectively in malignant colonocytes (AI in 5-FU-group: 0.126 +/- 0.016 [mean +/- SEM] vs. 0.065 +/- 0.012 in controls; P < 0.05), but not in normal colonocytes. 5-Fluorouracil had no effect on the PI of either normal or malignant colonocytes. 5-Fluorouracil-induced apoptosis did not correlate with clinical outcome at 24 months. We conclude that 5-FU: (a) induces apoptosis selectively in colon cancer cells, while it spares the normal colonic mucosa, and (b) has no effect on colonocyte proliferation under the conditions of our protocol. This effect of 5-FU may contribute to its chemotherapeutic activity in human colon cancer.

JTE-522-induced apoptosis in human gastric adenocarinoma cell line AGS cells by caspase activation accompanying cytochrome C release, membrane translocation of Bax and loss of mitochondrial membrane potential

AIM: To investigate the role of the mitochondrial pathway in JTE-522-induced apoptosis and to investigate the relationship between cytochrome C release, caspase activity and loss of mitochondrial membrane potential (△Ψm).

METHODS: Cell culture, cell counting, ELISA assay, TUNEL, flow cymetry, Western blot and fluorometric assay were employed to investigate the effect of JTE-522 on cell proliferation and apoptosis in AGS cells and related molecular mechanism.

RESULTS: JTE-522 inhibited the growth of AGS cells and induced the apoptosis. Caspases 8 and 9 were activated during apoptosis as judged by the appearance of cleavage products from procaspase and the caspase activities to cleave specific fluorogenic substrates. To elucidate whether the activation of caspases 8 and 9 was required for the apoptosis induction, we examined the effect of caspase-specific inhibitors on apoptosis. The results showed that caspase inhibitors significantly inhibited the apoptosis induced by JTE-522. In addition, the membrane translocation of Bax and cytosolic release of cytochrome C accompanying with the decrease of the uptake of Rhodamin 123, were detected at an early stage of apoptosis. Furthermore, Bax translocation, cytochrome C release, and caspase 9 activation were blocked by Z-VAD.fmk and Z-IETD-CHO.

CONCLUSION: The present data indicate a crucial association between activation of caspases 8, 9, cytochrome C release, membrane translocation of Bax, loss of △Ψm and JTE-522-induced apoptosis in AGS cells.

NSAID inhibition of GI cancer growth: clinical implications and molecular mechanisms of action

Epidemiological studies suggest that aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) reduce the incidence of and mortality from colorectal, gastric, and esophageal cancers. The precise mechanisms by which NSAIDs exert their chemopreventive effects are not fully explained, but likely involve inhibition of cyclo-oxygenase, the enzyme that converts arachidonic acid to prostaglandins. Two isoforms of this enzyme, cyclo-oxygenase 1 (COX-1) and COX-2, have been identified. COX-2 is absent in normal mucosa but is overexpressed in colonic, gastric, and esophageal cancers, as well as their precursor lesions. The inhibition of COX-2 through either pharmacological agents or gene deletion results in suppression of colonic polyp formation. NSAIDs reduce colonic, gastric, and esophageal cancer cell growth, in part, by inducing apoptosis. However, the antineoplastic effects of NSAIDs may be partly independent of their ability to inhibit COX-2. The mechanisms involved in the antineoplastic actions of NSAIDs include inhibition of angiogenesis (essential for delivery of oxygen and nutrients to a growing tumor), induction of apoptosis (which is usually reduced in cancer cells) by stimulation of proapoptotic genes, and direct inhibition of cancer cell growth by blocking signal transduction pathways responsible for cell proliferation.

Is inhibition of cyclooxygenase required for the anti-tumorigenic effects of nonsteroidal, anti-inflammatory drugs (NSAIDs)? In vitro versus in vivo results and the relevance for the prevention and treatment of cancer

Active research is being conducted to unravel the cellular mechanisms mediating the anti-tumorigenic effects of nonsteroidal anti-inflammatory drugs (NSAIDs) and their association with cyclooxygenase (COX) inhibition. The majority of NSAIDs inhibit either COX-1, COX-2, or both and exert their anti-COX, anti-inflammatory, and anti-tumorigenic effects in vivo in a parallel dose-dependent manner. The effects are seen at NSAID blood plasma concentrations of 0.1-5 microM. Significantly, the same compounds tested at the same concentrations in incubations with cultured tumor cells in vitro similarly inhibit COX activities but are devoid of anti-proliferative activity. Yet, at much higher concentrations (100-20,000 microM), these same NSAIDs do exert anti-proliferative effects in vitro due to apparent non-specific toxic effects, as evidenced by disruption of ion transport and mitochondrial oxidation in some cells. A small group of NSAIDs (e.g. sulindac) do not inhibit COX enzymes significantly but can reduce the synthesis of prostanoids by alternate mechanisms. One such mechanism is inhibition of agonist-stimulated phospholipase-mediated release of arachidonic acid from phospholipids leading to depressed synthesis of prostanoids, especially prostaglandin E(2) (PGE(2)). Another group of non-COX inhibitors are the R-isomers of NSAIDs, based on the structure of 2-arylpropionic acid. These compounds exert anti-proliferative effects in vivo, acting by an as yet undetermined mechanism. A possible caveat in these data is an R to S chiral transformation in vivo that would render the R-isomer effect as being due to the S-isomer generated in vivo from it. Demonstration of minimal or no R to S inversion under the experimental in vivo conditions employed is, therefore, a necessary control in these studies. The overall body of data supports the conclusion that, for COX-inhibiting NSAIDs, their anti-tumorigenic effect in vivo is due to, and depends upon, inhibition of tumor COX enzymes, primarily COX-2. The cellular effects seen when adding high concentrations of NSAIDs to tumor cells cultured in vitro and the mechanisms proposed to mediate these effects may not have substantial relevance to the mechanisms that mediate the effects of NSAIDs in vivo.

Enhanced apoptosis and transforming growth factor-beta1 expression in colorectal adenomas and carcinomas after Sulindac therapy

PURPOSE

We tried to elucidate the effects of sulindac on human colorectal carcinoma.

METHODS

Sulindac (300 mg/day) was administered for two weeks before operation to 33 patients with sporadic colorectal carcinoma (Sulindac Group). Resected specimens were used to detect apoptosis by terminal dUTP nick end labeling and transforming growth factor (TGF)-beta1 expression by immunohistochemistry. The results were compared with those from the historical Control Group. Twenty-nine available preoperative biopsies taken from carcinomas before sulindac prescription and 22 concurrent colorectal adenomas (9 and 13 in Sulindac and Control Groups, respectively) in the resected specimen were also examined regarding TGF-beta1 expression.

RESULTS

In the resected carcinomas and adenomas, more frequent apoptosis and higher TGF-beta1 scores were observed in the Sulindac Group than in the Control Group. Overexpression of TGF-beta1 and apoptosis occurred in the same region in adenomas but not in carcinomas. A positive correlation between TGF-beta1 scores and apoptotic frequency was found in adenomas (P = 0.01, rho = 0.91) but not in carcinomas (P = 0.89, rho = 0.03).

CONCLUSION

We conclude that sulindac induces apoptosis in human colorectal carcinomas as well as in adenomas. Also, one of the antineoplastic effects of sulindac might be mediated by upregulating TGF-beta1 expression, particularly in colorectal adenomas.

Biochemistry of cyclooxygenase (COX)-2 inhibitors and molecular pathology of COX-2 in neoplasia

Several types of human tumors overexpress cyclooxygenase (COX) -2 but not COX-1, and gene knockout transfection experiments demonstrate a central role of COX-2 in experimental tumorigenesis. COX-2 produces prostaglandins that inhibit apoptosis and stimulate angiogenesis and invasiveness. Selective COX-2 inhibitors reduce prostaglandin synthesis, restore apoptosis, and inhibit cancer cell proliferation. In animal studies they limit carcinogen-induced tumorigenesis. In contrast, aspirin-like nonselective NSAIDs such as sulindac and indomethacin inhibit not only the enzymatic action of the highly inducible, proinflammatory COX-2 but the constitutively expressed, cytoprotective COX-1 as well. Consequently, nonselective NSAIDs can cause platelet dysfunction, gastrointestinal ulceration, and kidney damage. For that reason, selective inhibition of COX-2 to treat neoplastic proliferation is preferable to nonselective inhibition. Selective COX-2 inhibitors, such as meloxicam, celecoxib (SC-58635), and rofecoxib (MK-0966), are NSAIDs that have been modified chemically to preferentially inhibit COX-2 but not COX-1. For instance, meloxicam inhibits the growth of cultured colon cancer cells (HCA-7 and Moser-S) that express COX-2 but has no effect on HCT-116 tumor cells that do not express COX-2. NS-398 induces apoptosis in COX-2 expressing LNCaP prostate cancer cells and, surprisingly, in colon cancer S/KS cells that does not express COX-2. This effect may due to induction of apoptosis through uncoupling of oxidative phosphorylation and down-regulation of Bcl-2, as has been demonstrated for some nonselective NSAIDs, for instance, flurbiprofen. COX-2 mRNA and COX-2 protein is constitutively expressed in the kidney, brain, spinal cord, and ductus deferens, and in the uterus during implantation. In addition, COX-2 is constitutively and dominantly expressed in the pancreatic islet cells. These findings might somewhat limit the use of presently available selective COX-2 inhibitors in cancer prevention but will probably not deter their successful application for the treatment of human cancers.

The role of COX-2 in intestinal cancer

Cyclooxygenase (COX), the key regulatory enzyme for prostaglandin synthesis is transcribed from two distinct genes. COX-1 is expressed constitutively in most tissues, and COX-2 is induced by a wide variety of stimuli and was initially identified as an immediate-early growth response gene. In addition, COX-2 expression is markedly increased in 85-90% of human colorectal adenocarcinomas, whereas COX-1 levels remain unchanged. Several epidemiological studies have reported a 40-50% reduction in the risk of developing colorectal cancer in persons who chronically take such nonsteroidal anti-inflammatory drugs (NSAIDs) as aspirin, which are classic inhibitors of cyclooxygenase. Genetic evidence also supports a role for COX-2, since mice null for COX-2 have an 86% reduction in tumor multiplicity in a background containing a mutated APC allele. These results strongly suggest that COX-2 contributes to the development of intestinal tumors and that inhibition of COX is chemo-preventative.

Is inhibition of cyclooxygenase required for the chemopreventive effect of NSAIDs in colon cancer? A model reconciling the current contradiction

NSAIDs are powerful chemopreventive agents for colon cancer, but their mechanism of action remains unknown. Their best recognized pharmacological property is inhibition of the enzyme cyclooxygenase (COX), which catalyzes the synthesis of prostaglandins; however, additional effects are well documented. Current studies on the mechanism of the chemopreventive effect of NSAIDs lead to two contradictory conclusions: NSAIDs prevent colon cancer either by inhibiting the activity of COX, or through mechanisms that do not require COX inhibition. To resolve this apparent conflict, after examining several alternatives, we propose a model, which assumes that both mechanisms are correct but that they exert their effect either on different steps of the multistep process of colon carcinogenesis or on different control mechanisms. This postulated dual action of NSAIDs may explain their remarkable effectiveness in colon cancer prevention. Unraveling these mechanistic details can be very rewarding for the design of more refined approaches to cancer chemoprevention and for a deeper understanding of colorectal carcinogenesis.

Sodium salicylate inhibits proliferation and induces G1 cell cycle arrest in human pancreatic cancer cell lines

The mutations most common in pancreatic cancer decrease the ability to control G1 to S cell cycle progression and cellular proliferation. In colorectal cancer cells, nonsteroidal anti-inflammatory drugs inhibit proliferation and induce cell cycle arrest. We examined whether sodium salicylate, an aspirin metabolite, could inhibit proliferation in human pancreatic cancer cell lines (BxPC3 and Panc-1). Quiescent cells were treated with medium containing 10% fetal calf serum, with or without salicylate. Cellular proliferation was measured by MTT assay and bromodeoxyuridine incorporation. The fractions of cells in G0/G1, S, and G2/M phases of the cell cycle were quantitated by fluorescence-activated cell sorting. Results were compared between groups by two-tailed t test. Cyclin D1 expression was determined by Western blot analysis and prostaglandin E2 expression by enzyme-linked immunosorbent assay. Serum-starved cells failed to proliferate, with most arrested in the G1 phase. Salicylate significantly inhibited serum-induced progression from G1 to S phase, cellular proliferation, and the expression of cyclin D1. The concentrations at which 50% of serum-induced proliferation was inhibited were 1.2 mmol/L (Panc-1) and 1.7 mmol/L (BxPC3). The antiproliferative effect of sodium salicylate was not explained by inhibition of prostaglandin E2 production. This study provides further evidence in a noncolorectal cancer model for the antineoplastic effects of nonsteroidal anti-inflammatory drugs.

Non steroidal anti-inflammatory drugs and colorectal cancer: is there a way forward?

Non steroidal anti-inflammatory drugs (NSAIDs) have diverse clinical applications through modulation of oxidative processes and cell signalling. Observations that these agents may inhibit human colorectal carcinogenesis have produced great excitement. However, comparative data relating to their chemopreventative effectiveness or to relevant mechanisms of action remains unclear. This review considers the clinical and epidemiological evidence for colorectal tumour prevention by NSAIDs against current concepts of drug mechanisms. We also propose areas of further research for potential therapeutic advancement.

Effects of NSAIDs on proliferation of gastric cancer cells in vitro: possible implication of cyclooxygenase-2 in cancer development

The roles of cyclooxygenase-2 (COX-2) in the development of gastric cancer are unknown. We investigated the effects of nonsteroidal antiinflammatory drugs (NSAIDs), which are specific and nonspecific inhibitors of COX-2, on proliferation of the gastric cancer cell lines KATOIII, MKN28, and MKN45. The protein level of COX-2 was examined in these cell lines by Western analysis, and mRNA levels of COX-1/2 by Northern analysis. These cell lines expressed comparable levels of COX-1 mRNA. However, mRNA and protein expression of COX-2 in these cell lines was different. MKN45 expressed higher levels of COX-2 mRNA and protein than KATOIII and MKN28. We also examined the effects of NS-398 and indomethacin, specific and nonspecific inhibitors of COX-2, on the increase in cell number and [3H]thymidine uptake of these cell lines. NS-398 and indomethacin suppressed proliferation of MKN45 cells that overexpressed COX-2, although they exerted minimal effects on proliferation of KATOIII and MKN28, which expressed lower levels of COX-2. These results are consistent with the hypothesis that COX-2 is expressed in certain groups of gastric cancers and is related to their cell proliferation. It was proposed that COX-2 plays an important role in development of gastric cancer cells. Furthermore, NSAIDs may exert antiproliferative activity against gastric adenocarcinomas that overexpress COX-2.

Sulindac sulfide alters the expression of cyclin proteins in HT-29 colon adenocarcinoma cells

Sulindac sulfide (SS), the active metabolite of the colon cancer chemopreventive compound sulindac, inhibits the proliferation of HT-29 colon cancer cells mainly by inducing cell quiescence. We determined by bivariate flow-cytometric analysis both the DNA and cyclin protein content of individual cells. Thus, we assessed in detail the expression of several cyclins during the cell-cycle phases and demonstrated that SS (i) decreases the expression of cyclins B1 and E and (ii) increases the expression of cyclins D1, D2 and D3, particularly in the G1 phase of the cell cycle. SS-induced apoptotic cells expressed both E- and D-type cyclins but not cyclin B1. The changes in cyclin expression combined with reduced catalytic activity of cyclin-dependent kinases could explain in molecular terms the anti-proliferative effect of SS on HT-29 colon cancer cells. These changes may contribute to the chemopreventive effect of sulindac.