Inhibition of COX-2 in colon cancer modulates tumor growth and MDR-1 expression to enhance tumor regression in therapy-refractory cancers in vivo. Neoplasia. 2012;14:624-633. [PMID: 22904679 DOI: 10.1593/neo.12486]

Synthesis and Biological Evaluation of Some New 3-Aryl-2-thioxo-2,3-dihydroquinazolin-4(1H)-ones and 3-Aryl-2-(benzylthio)quinazolin-4(3H)-ones as Antioxidants; COX-2, LDHA, α-Glucosidase and α-Amylase Inhibitors; and Anti-Colon Carcinoma and Apoptosis-Inducing Agents

Oxidative stress, COX-2, LDHA and hyperglycemia are interlinked contributing pathways in the etiology, progression and metastasis of colon cancer. Additionally, dysregulated apoptosis in cells with genetic alternations leads to their progression in malignant transformation. Therefore, quinazolinones 3a-3h and 5a-5h were synthesized and evaluated as antioxidants, enzymes inhibitors and cytotoxic agents against LoVo and HCT-116 cells. Moreover, the most active cytotoxic derivatives were evaluated as apoptosis inducers. The results indicated that 3a, 3g and 5a were efficiently scavenged DPPH radicals with lowered IC50 values (mM) ranging from 0.165 ± 0.0057 to 0.191 ± 0.0099, as compared to 0.245 ± 0.0257 by BHT. Derivatives 3h, 5a and 5h were recognized as more potent dual inhibitors than quercetin against α-amylase and α-glucosidase, in addition to 3a, 3c, 3f and 5b-5f against α-amylase. Although none of the compounds demonstrated a higher efficiency than the reference inhibitors against COX-2 and LDHA, 3a and 3g were identified as the most active derivatives. Molecular docking studies were used to elucidate the binding affinities and binding interactions between the inhibitors and their target proteins. Compounds 3a and 3f showed cytotoxic activities, with IC50 values (µM) of 294.32 ± 8.41 and 383.5 ± 8.99 (LoVo), as well as 298.05 ± 13.26 and 323.59 ± 3.00 (HCT-116). The cytotoxicity mechanism of 3a and 3f could be attributed to the modulation of apoptosis regulators (Bax and Bcl-2), the activation of intrinsic and extrinsic apoptosis pathways via the upregulation of initiator caspases-8 and -9 as well as executioner caspase-3, and the arrest of LoVo and HCT-116 cell cycles in the G2/M and G1 phases, respectively. Lastly, the physicochemical, medicinal chemistry and ADMET properties of all compounds were predicted.

Investigation of the anti-cancer potential of epoxyazadiradione in neuroblastoma: experimental assays and molecular analysis

Neuroblastoma, the most common childhood solid tumor, originates from primitive sympathetic nervous system cells. Epoxyazadiradione (EAD) is a limonoid derived from Azadirachta indica, belonging to the family Meliaceae. In this study, we isolated the EAD from Azadirachta indica seed and studied the anti-cancer potential against neuroblastoma. Herein, EAD demonstrated significant efficacy against neuroblastoma by suppressing cell proliferation, enhancing the rate of apoptosis and cycle arrest at the SubG0 and G2/M phases. EAD enhanced the pro-apoptotic Caspase 3 and Caspase 9 and inhibited the NF-kβ translocation in a dose-dependent manner. In order to identify the specific EAD target, a gel-free quantitative proteomics study on SH-SY5Y cells using Liquid Chromatography with tandem mass spectrometry was done in a dose-dependent manner, followed by detailed bioinformatics analysis to identify effects on protein. Proteomics data identified that Enolase1 and HSP90 were up-regulated in neuroblastoma. EAD inhibited the expression of Enolase1 and HSP90, validated by mRNA expression, immunoblotting, Enolase1 and HSP90 kit and flow-cytometry based bioassay. Molecular docking study, Molecular dynamic simulation, and along with molecular mechanics/Poisson-Boltzmann surface area analysis also suggested that EAD binds at the active site of the proteins and were stable throughout the 100 ns Molecular dynamic simulation study. Overall, this study suggested EAD exhibited anti-cancer activity against neuroblastoma by targeting Enolase1 and HSP90 pathways.Communicated by Ramaswamy H. Sarma.

Fluorinated Benzofuran and Dihydrobenzofuran as Anti-Inflammatory and Potential Anticancer Agents

Benzofuran and 2,3-dihydrobenzofuran scaffolds are heterocycles of high value in medicinal chemistry and drug synthesis. Targeting inflammation in cancer associated with chronic inflammation is a promising therapy. In the present study, we investigated the anti-inflammatory effects of fluorinated benzofuran and dihydrobenzofuran derivatives in macrophages and in the air pouch model of inflammation, as well as their anticancer effects in the human colorectal adenocarcinoma cell line HCT116. Six of the nine compounds suppressed lipopolysaccharide-stimulated inflammation by inhibiting the expression of cyclooxygenase-2 and nitric oxide synthase 2 and decreased the secretion of the tested inflammatory mediators. Their IC₅₀ values ranged from 1.2 to 9.04 µM for interleukin-6; from 1.5 to 19.3 µM for Chemokine (C-C) Ligand 2; from 2.4 to 5.2 µM for nitric oxide; and from 1.1 to 20.5 µM for prostaglandin E₂. Three novel synthesized benzofuran compounds significantly inhibited cyclooxygenase activity. Most of these compounds showed anti-inflammatory effects in the zymosan-induced air pouch model. Because inflammation may lead to tumorigenesis, we tested the effects of these compounds on the proliferation and apoptosis of HCT116. Two compounds with difluorine, bromine, and ester or carboxylic acid groups inhibited the proliferation by approximately 70%. Inhibition of the expression of the antiapoptotic protein Bcl-2 and concentration-dependent cleavage of PARP-1, as well as DNA fragmentation by approximately 80%, were described. Analysis of the structure-activity relationship suggested that the biological effects of benzofuran derivatives are enhanced in the presence of fluorine, bromine, hydroxyl, and/or carboxyl groups. In conclusion, the designed fluorinated benzofuran and dihydrobenzofuran derivatives are efficient anti-inflammatory agents, with a promising anticancer effect and a combinatory treatment in inflammation and tumorigenesis in cancer microenvironments.

Natural-Derived COX-2 Inhibitors as Anticancer Drugs: A Review of their Structural Diversity and Mechanism of Action

Cyclooxygenase-2 (COX-2) is a key-type enzyme playing a crucial role in cancer development, making it a target of high interest for drug designers. In the last two decades, numerous selective COX-2 inhibitors have been approved for various clinical conditions. However, data from clinical trials propose that the prolonged use of COX-2 inhibitors is associated with life-threatening cardiovascular side effects. The data indicate that a slight structural modification can help develop COX-2 selective inhibitors with comparative efficacy and limited side effects. In this regard, secondary metabolites from natural sources offer great hope for developing novel COX-2 inhibitors with potential anticancer activity. In recent years, various nature-derived organic scaffolds are being explored as leads for developing new COX-2 inhibitors. The current review attempts to highlight the COX-2 inhibition activity of some naturally occurring secondary metabolites, concerning their capacity to inhibit COX-1 and COX-2 enzymes and inhibit cancer development, aiming to establish a structure-activity relationship.

Glycyrrhizin as a Nitric Oxide Regulator in Cancer Chemotherapy

Simple Summary

Glycyrrhizin (GL) has anti-cancer, anti-inflammatory, anti-viral, and anti-oxidant activity. In particular, GL reduces multidrug resistance (MDR) in cancer cells, which is a major obstacle to chemotherapy. Nitric oxide (NO) also plays an important role in MDR, and GL affects NO concentration in the tumor microenvironment. However, the effects of GL and NO interaction on MDR have not been reviewed. Here, we review the role of GL as an NO regulator in cancer cells and its subsequent anti-MDR effect and posit that GL is a promising MDR inhibitor for cancer chemotherapy.

Abstract

Chemotherapy is used widely for cancer treatment; however, the evolution of multidrug resistance (MDR) in many patients limits the therapeutic benefits of chemotherapy. It is important to overcome MDR for enhanced chemotherapy. ATP-dependent efflux of drugs out of cells is the main mechanism of MDR. Recent studies have suggested that nitric oxide (NO) can be used to overcome MDR by inhibiting the ATPase function of ATP-dependent pumps. Several attempts have been made to deliver NO to the tumor microenvironment (TME), however there are limitations in delivery. Glycyrrhizin (GL), an active compound of licorice, has been reported to both reduce the MDR effect by inhibiting ATP-dependent pumps and function as a regulator of NO production in the TME. In this review, we describe the potential role of GL as an NO regulator and MDR inhibitor that efficiently reduces the MDR effect in cancer chemotherapy.

A Systematic Review of the Cyclooxygenase-2 (COX-2) Expression in Rectal Cancer Patients Treated with Preoperative Radiotherapy or Radiochemotherapy

The main objective of this systematic review is to investigate the expression level of the cyclooxygenase-2 (COX-2) in rectal cancer treated with either preoperative radiotherapy or radiochemotherapy. In addition, we have summarized the effects of preoperative treatment of rectal cancer with regards to the expression levels of COX-2. A systematic literature review was performed in The Cochrane Library, PubMed, Web of Science, and Scopus databases on 1 January 2021 with the usage of the following search string-(cyclooxygenase-2) OR (COX-2) AND (rectal cancer) AND (preoperative radiochemotherapy) OR (preoperative radiotherapy). Among the 176 included in the analysis, only 13 studies were included for data extraction with a total number of 2095 patients. The results of the analysis are based on the articles concerning the expression of COX-2 in rectal cancer among patients treated with preoperative radiotherapy or radiochemotherapy. A COX-2 expression is an early event involved in rectal cancer development. In cases of negative COX-2 expression, radiotherapy and radiochemotherapy might contribute to the reduction of a local recurrence. Therefore, COX-2 may be considered as a biologic factor while selecting patients for more effective, less time-consuming and less expensive preoperative treatment. However, the utility of the administration of COX-2 inhibitors to patients with COX-2 overexpression, in an attempt to improve the patients' response rate to the neoadjuvant treatment, needs an assessment in further clinical trials.

Inhibition of nucleophosmin 1 suppresses colorectal cancer tumor growth of patient -derived xenografts via activation of p53 and inhibition of AKT

The nucleophosmin 1 (NPM1) protein is frequently overexpressed in various cancers compared to normal tissues and represents a potential biomarker for maliganancy. However, its role in colorectal cancer (CRC) is still not fully understood. In this report, we show that NPM1 levels in CRC correlate with prognosis and sensitivity to chemotherapy. NPM1 expression was found to be significantly increased in CRC tumors (P < .001) and was associated with poor overall 5-year survival (P < .05). For individuals with Stage IV disease, this represented a reduction in survival by 11 months (P < .01; HR = 0.38, CI [0.21, 0.69]. In vitro, we show that NPM1 gene silencing enhanced the chemosensitivity of CRC cells and that pharmacological inhibition of NPM1 by NSC348884 triggered the onset of programmed cell death. Our immunofluorescence microscopy and immunoblot analyses also revealed that blocking NPM1 function sensitized CRC cells to chemotherapy-induced apoptosis through a mechanism that involves proteins in the AKT pathway. Consistent with the in vitro data, our patient-derived CRC xenograft model showed that inhibition of NPM1 suppressed tumor growth and attenuated AKT signaling in vivo. Moreover, LY294002, an inhibitor of the PI3K/AKT pathway, restored the chemosensitivity of CRC cells expressing high levels of NPM1. The findings that NPM1's expression in CRC tissue correlates with prognosis and supports anti-apoptotic activity mediated by AKT signaling, further our understanding of the role of NPM1 in CRC.

The Prognostic Significance of 5-Fluorouracil Induced Inflammation and Immuno-Modulation in Colorectal Cancer Patients

Aim

The change in the levels of peripheral inflammatory markers together with EGFR in relation to 5- fluorouracil (5-FU) therapy was evaluated for their prognostic significance in colorectal cancer (CRC) patients.

Patients and Methods

Expression levels of COX2, IL6, IL1β, EGFR, IL10, and TNFα were determined with quantitative real-time PCR (qPCR) in the peripheral blood of 90 CRC patients. The inflammatory response was correlated with patients’ clinical features, disease-free survival (DFS), and overall survival (OS).

Results

After 6 months of 5-FU therapy, increased inflammatory response was found to be associated with smoking, T3 or T4 tumors, performance status (PS) III, positive lymph nodes, distant metastasis, and gastrointestinal (GIT) toxicity. The combination of COX2 with interleukins in a predictive equation for DFS was significant in patients with over-expression of EGFR. DFS and OS rates were reduced in patients with increased COX2, IL6, IL10, and TNFα expression with 5-FU therapy. Significant hazard of disease progression was associated with smoking (HR=1.27, P=0.004), 5-FU induction of COX2, and IL6 expression (HR=1.35, P=0.001 and HR=1.27, P=0.004, respectively). Moreover, smoking, 5-FU induction of IL6, TNFα, and IL10 expression are found to be independent prognostic factors for OS (P=0.003, 0.003, 0.002, and 0.002, respectively).

Conclusion

The peripheral effects of 5-FU therapy have shown a significant impact on the treatment outcome of CRC patients.

Antiplatelet Therapy Improves the Prognosis of Patients with Hepatocellular Carcinoma

Simple Summary

Antiplatelet therapy shows antitumor effect in several types of cancers. In liver disease, antiplatelet therapy reduces liver fibrosis and occurrence of HCC. However, the effect after diagnosis of hepatocellular carcinoma is still unknown. Therefore, we aimed to clarify the effects of antiplatelet therapy for HCC patients in this study. We compared patients with and without antiplatelet therapy in overall survival, liver-related death, tumor progression, Child-Pugh deterioration and bleeding. Our results suggested that antiplatelet therapy had antitumor effect, liver protective effect and safety. Therefore, patients with antiplatelet therapy could reduce liver-related death and improve overall survival.

Abstract

Aims: Antiplatelet therapy has been reported to reduce liver fibrosis and hepatocellular carcinoma (HCC), and has exhibited antitumor properties in other cancers. However, the effects of antiplatelet therapy after diagnosis of HCC are unknown. We investigated the effects of antiplatelet therapy on prognosis, tumor progression, liver function and safety in HCC patients. Methods: We retrospectively analyzed 772 HCC patients. Antiplatelet therapy was defined as the regular intake of aspirin or clopidogrel from HCC diagnosis through to an endpoint of either overall survival (OS) or liver-related death. Overall survival, liver-related death, tumor progression, Child–Pugh deterioration and hemorrhage were analyzed for patients who either had or had not undertaken antiplatelet therapy. Results: The numbers of patients who did and did not undertake antiplatelet therapy were 111 and 661, respectively. Patients who undertook antiplatelet therapy were older and had better liver function at diagnosis. Antiplatelet therapy resulted in significant improvements in OS (p < 0.01) and lower risk of liver-related death (p < 0.01). Multivariate Cox regression analysis revealed that antiplatelet therapy had a significant negative association with liver-related death (hazard ratio (HR): 0.64, 95% confidence interval (CI): 0.44–0.93, p = 0.02). In patients who underwent transcatheter arterial chemoembolization (TACE) as the first treatment, antiplatelet therapy prevented tumor progression (p < 0.01) and Child–Pugh deterioration (p < 0.01). Antiplatelet therapy did not increase the risk of hemorrhagic events. Conclusions: Antiplatelet therapy reduced liver-related death and improved OS safely in HCC patients.

Cellular Mechanisms Accounting for the Refractoriness of Colorectal Carcinoma to Pharmacological Treatment

Simple Summary

Colorectal cancer (CRC) causes a high number (more than 800,000) of deaths worldwide each year. Better methods for early diagnosis and the development of strategies to enhance the efficacy of the therapeutic approaches used to complement or substitute surgical removal of the tumor are urgently needed. Currently available pharmacological armamentarium provides very moderate benefits to patients due to the high resistance of tumor cells to respond to anticancer drugs. The present review summarizes and classifies into seven groups the cellular and molecular mechanisms of chemoresistance (MOC) accounting for the failure of CRC response to the pharmacological treatment.

Abstract

The unsatisfactory response of colorectal cancer (CRC) to pharmacological treatment contributes to the substantial global health burden caused by this disease. Over the last few decades, CRC has become the cause of more than 800,000 deaths per year. The reason is a combination of two factors: (i) the late cancer detection, which is being partially solved by the implementation of mass screening of adults over age 50, permitting earlier diagnosis and treatment; (ii) the inadequate response of advanced unresectable tumors (i.e., stages III and IV) to pharmacological therapy. The latter is due to the existence of complex mechanisms of chemoresistance (MOCs) that interact and synergize with each other, rendering CRC cells strongly refractory to the available pharmacological regimens based on conventional chemotherapy, such as pyrimidine analogs (5-fluorouracil, capecitabine, trifluridine, and tipiracil), oxaliplatin, and irinotecan, as well as drugs targeted toward tyrosine kinase receptors (regorafenib, aflibercept, bevacizumab, cetuximab, panitumumab, and ramucirumab), and, more recently, immune checkpoint inhibitors (nivolumab, ipilimumab, and pembrolizumab). In the present review, we have inventoried the genes involved in the lack of CRC response to pharmacological treatment, classifying them into seven groups (from MOC-1 to MOC-7) according to functional criteria to identify cancer cell weaknesses. This classification will be useful to pave the way for developing sensitizing tools consisting of (i) new agents to be co-administered with the active drug; (ii) pharmacological approaches, such as drug encapsulation (e.g., into labeled liposomes or exosomes); (iii) gene therapy interventions aimed at restoring the impaired function of some proteins (e.g., uptake transporters and tumor suppressors) or abolishing that of others (such as export pumps and oncogenes).

The Mechanism of Bacteroides fragilis Toxin Contributes to Colon Cancer Formation

The Bacteroides fragilis (B. fragilis) produce biofilm for colonisation in the intestinal tract can cause a series of inflammatory reactions due to B. fragilis toxin (BFT) which can lead to chronic intestinal inflammation and tissue injury and play a crucial role leading to colorectal cancer (CRC). The enterotoxigenic B. fragilis (ETBF) forms biofilm and produce toxin and play a role in CRC, whereas the non-toxigenic B. fragilis (NTBF) does not produce toxin. The ETBF triggers the expression of cyclooxygenase (COX)-2 that releases PGE2 for inducing inflammation and control cell proliferation. From chronic intestinal inflammation to cancer development, it involves signal transducers and activators of transcription (STAT)3 activation. STAT3 activates by the interaction between epithelial cells and BFT. Thus, regulatory T-cell (Tregs) will activates and reduce interleukin (IL)-2 amount. As the level of IL-2 drops, T-helper (T_h17) cells are generated leading to increase in IL-17 levels. IL-17 is implicated in early intestinal inflammation and promotes cancer cell survival and proliferation and consequently triggers IL-6 production that activate STAT3 pathway. Additionally, BFT degrades E-cadherin, hence alteration of signalling pathways can upregulate spermine oxidase leading to cell morphology and promote carcinogenesis and irreversible DNA damage. Patient with familial adenomatous polyposis (FAP) disease displays a high level of tumour load in the colon. This disease is caused by germline mutation of the adenomatous polyposis coli (APC) gene that increases bacterial adherence to the mucosa layer. Mutated-APC gene genotype with ETBF increases the chances of CRC development. Therefore, the colonisation of the ETBF in the intestinal tract depicts tumour aetiology can result in risk of hostility and effect on human health.

Expression and Cellular Distribution of P-Glycoprotein and Breast Cancer Resistance Protein in Amyotrophic Lateral Sclerosis Patients

For amyotrophic lateral sclerosis (ALS), achieving and maintaining effective drug levels in the brain is challenging due to the activity of ATP-binding cassette (ABC) transporters which efflux drugs that affect drug exposure and response in the brain. We investigated the expression and cellular distribution of the ABC transporters P-glycoprotein (P-gp) and breast cancer resistance protein (BCRP) using immunohistochemistry in spinal cord (SC), motor cortex, and cerebellum from a large cohort of genetically well characterized ALS patients (n = 25) and controls (n = 14). The ALS group included 17 sporadic (sALS) and 8 familial (fALS) patients. Strong P-gp expression was observed in endothelial cells in both control and ALS specimens. Immunohistochemical analysis showed higher P-gp expression in reactive astroglial cells in both gray (ventral horn) and white matter of the SC, as well as in the motor cortex of all ALS patients, as compared with controls. BCRP expression was higher in glia in the SC and in blood vessels and glia in the motor cortex of ALS patients, as compared with controls. P-gp and BCRP immunoreactivity did not differ between sALS and fALS cases. The upregulation of both ABC transporters in the brain may explain multidrug resistance in ALS patients and has implications for the use of both approved and experimental therapeutics.

Cannabinoid Effects on Experimental Colorectal Cancer Models Reduce Aberrant Crypt Foci (ACF) and Tumor Volume: A Systematic Review

OBJECTIVE

Colorectal cancer represents a heavy burden for health systems worldwide, being the third most common cancer worldwide. Despite the breakthroughs in medicine, current chemotherapeutic options continue to have important side effects and may not be effective in preventing disease progression. Cannabinoids might be substances with possible therapeutic potential for cancer because they can attenuate the side effects of chemotherapy and have antiproliferative and antimetastatic effects. We aim to determine, through a systematic review of experimental studies performed on animal CRC models, if cannabinoids can reduce the formation of preneoplastic lesions (aberrant crypt foci), number, and volume of neoplastic lesions.

MATERIALS AND METHODS

A systematic, qualitative review of the literature was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. PubMed, Embase, and Scopus databases were searched. We use the following Medical Subject Headings (MESH) terms in PubMed: "colorectal neoplasms," "colonic neoplasms," "colorectal cancer," "polyps," "rimonabant," "cannabidiol," "cannabinoids," "azoxymethane," "xenograft," and "mice." Only studies that met the eligibility criteria were included.

RESULTS

Eight in vivo experimental studies were included in the analysis after the full-text evaluation. Seven studies were azoxymethane (AOM) colorectal cancer models, and four studies were xenograft models. Cannabidiol botanical substance (CBD BS) and rimonabant achieved high aberrant crypt foci (ACF) reduction (86% and 75.4%, respectively). Cannabigerol, O-1602, and URB-602 demonstrated a high capacity for tumor volume reduction. Induction of apoptosis, interaction with cell survival, growth pathways, and angiogenesis inhibition were the mechanisms extracted from the studies that explain cannabinoids' actions on CRC.

CONCLUSIONS

Cannabinoids have incredible potential as antineoplastic agents as experimental models demonstrate that they can reduce tumor volume and ACF formation. It is crucial to conduct more experimental studies to understand the pharmacology of cannabinoids in CRC better.

Regulators of G-protein signaling, RGS2 and RGS4, inhibit protease-activated receptor 4-mediated signaling by forming a complex with the receptor and Gα in live cells

BACKGROUND

Protease-activated receptor 4 (PAR4) is a seven transmembrane G-protein coupled receptor (GPCR) activated by endogenous proteases, such as thrombin. PAR4 is involved in various pathophysiologies including cancer, inflammation, pain, and thrombosis. Although regulators of G-protein signaling (RGS) are known to modulate GPCR/Gα-mediated pathways, their specific effects on PAR4 are not fully understood at present. We previously reported that RGS proteins attenuate PAR1- and PAR2-mediated signaling through interactions with these receptors in conjunction with distinct Gα subunits.

METHODS

We employed a bioluminescence resonance energy transfer technique and confocal microscopy to examine potential interactions among PAR4, RGS, and Gα subunits. The inhibitory effects of RGS proteins on PAR4-mediated downstream signaling and cancer progression were additionally investigated by using several assays including ERK phosphorylation, calcium mobilization, RhoA activity, cancer cell proliferation, and related gene expression.

RESULTS

In live cells, RGS2 interacts with PAR4 in the presence of Gα_q while RGS4 binding to PAR4 occurs in the presence of Gα_q and Gα_12/13. Co-expression of PAR4 and Gα_q induced a shift in the subcellular localization of RGS2 and RGS4 from the cytoplasm to plasma membrane. Combined PAR4 and Gα_12/13 expression additionally promoted translocation of RGS4 from the cytoplasm to the membrane. Both RGS2 and RGS4 abolished PAR4-activated ERK phosphorylation, calcium mobilization and RhoA activity, as well as PAR4-mediated colon cancer cell proliferation and related gene expression.

CONCLUSIONS

RGS2 and RGS4 forms ternary complex with PAR4 in Gα-dependent manner and inhibits its downstream signaling. Our findings support a novel physiological function of RGS2 and RGS4 as inhibitors of PAR4-mediated signaling through selective PAR4/RGS/Gα coupling. Video Abstract.

Celecoxib in Cancer Therapy and Prevention - Review

BACKGROUND AND OBJECTIVES

It is generally accepted that inflammatory cells found in the tumor microenvironment are involved in the neoplastic process, promoting cell proliferation, survival, and migration. Therefore, administering anti-inflammatory medication in cancer therapy seems to be justified. A potential pathway associated with the aforementioned issue is cyclooxygenase-2 inhibition, particularly as the overexpression of this enzyme has been proven to occur in cancer tissues and is also associated with a poor prognosis in several types of human malignancies. Celecoxib, a COX-2 selective inhibitor, has been utilized for over 20 years, particularly as an anti-inflammatory, analgesic and antipyretic medication. However, to date, its antineoplastic properties have not been sufficiently investigated. In recent years, the number of research studies on the antineoplastic effects of celecoxib has increased considerably. The vast majority of publications refers to preclinical studies attempting to elucidate its mechanisms of action. Clinical trials concerning celecoxib have focused primarily on the treatment of cancers of the colon, breast, lung, prostate, stomach, head and neck, as well as premalignant lesions such as familial adenoma polyposis. In this review article authors attempt to summarise the latest research which has elucidated celecoxib use in the treatment and prevention of cancer.

CONCLUSION

Both preclinical and clinical studies have demonstrated promising results of the role of celecoxib in the treatment and prevention of cancer - the best outcome was observed in colon, breast, prostate and head and neck cancers. However, more clinical trials providing real evidence-based clinical advances of celecoxib use are needed.

BPTF cooperates with p50 NF-κB to promote COX-2 expression and tumor cell growth in lung cancer

Cyclooxygenase-2 (COX-2) is overexpressed in most human cancers, but its precise regulatory mechanism in cancer cells remains unclear. The aims of this study are to discover and identify the new regulatory factors which bind to the COX-2 promoter and regulate COX-2 expression and cancer cell growth, and to elucidate the mechanisms of action of these factors in lung cancer. In this study, the COX-2 promoter-binding protein BPTF (bromodomain PHD finger transcription factor) was detected, identified and verified by biotin-streptavidin-agarose pulldown, mass spectrum analysis and chromatin immunoprecipitation (ChIP) in lung cancer cells, respectively. The expressions of COX-2 and BPTF in lung cancer cell lines, mouse tumor tissues and human clinical samples were detected by RT-PCR, Western blot and immunohistochemistry assays. The interaction of BPTF with NF-kB was analyzed by immunoprecipitation and confocal immunofluorescence assays. We discovered and identified BPTF as a new COX-2 promoter-binding protein in human lung cancer cells. Knockdown of BPTF inhibited COX-2 promoter activity and COX-2 expression in lung cancer cells in vitro and in vivo. We also found that BPTF functioned as a transcriptional regulator through its interaction with the p50 subunit of NF-kB. Knockdown of BPTF abrogated the binding of p50 to the COX-2 promoter, while the inhibition of p50 activity abolished the decreased trend of COX-2 expression and lung cancer cell proliferation caused by BPTF silencing. Moreover, we showed that the expressions of BPTF and COX-2 in tumor tissues of lung cancer patients were positively correlated, and high co-expression of BPTF and COX-2 predicted poor prognosis in lung cancer patients. Collectively, our results indicated that BPTF cooperated with p50 NF-κB to regulate COX-2 expression and lung cancer growth, suggesting that the BPTF/p50/COX-2 axis could be a potential therapeutic target for lung cancer.

Computer-assisted engineering of programmed drug releasing multilayer nanomedicine via indomethacin-mediated ternary complex for therapy against a multidrug resistant tumor

Nanomedicine with programmed drug release can give full play to the synergistic effect of multi-component system in complicated tumor environment. However, the construction of these programmed drug delivery systems often depends on the sophisticated materials design and synthesis. In this study, we successfully designed an indomethacin (IND)-mediated ternary complex system based on a PEG cleavable polyethyleneimine (PEI), indomethacin (IND) and benzene ring containing chemotherapeutic drugs (such as paclitaxel (PTX), doxorubicin and docetaxel). Based on the difference of hydrophobicity in these components, these components were one-pot self-assembled into drug-loaded IND mediated PEGylation cleavable nanoassemblies (IPCNs) in multilayer structure. In drug-loaded IPCNs, PEG fragments, PEI/IND, and chemotherapeutic drug were respectively distributed from the out layer to core of nanomedicine. When drug-loaded IPCNs reached tumor site through EPR effect, the PEG fragment would firstly responsively release to the acidic tumor microenvironment to expose the intermediate layer of drug-loaded IPCNs that composed by mixture of PEI and IND for increasing the surface potential to promote the uptake by tumor cells. After entering cells, IND would be released faster than chemotherapeutic drug encapsulated in core to efficiently inhibit the expression of multidrug resistance protein 1 to reverse MDR of tumor cells before chemotherapeutic drug releasing. Contributed by the staged responsively releasing of PEG fragments, IND and encapsulated chemotherapeutic drug, the drug-loaded IPCNs exhibited a superior antitumor efficacy against A549/MDR tumor cells both in vitro and in vivo. STATEMENT OF SIGNIFICANCE: The way to develop programmed released drug delivery system is commonly relied on complicated material design and synthesis. Herein, under the computer-assist design, we successfully designed a ternary complex derived from indomethacin (IND), paclitaxel (PTX) and a pH-responsive PEGylated polyethyleneimine (PEG-s-PEI), and employed this ternary complex to successfully prepare a high drug loading and multilayer structured nanomedicine of PTX (PTX IPCNs). Contribute by the different location of PTX, IND and PEG-s-PEI in PTX IPCNs, PEG fragments, IND and PTX molecules could programmed release after reaching tumor for perfectly realizing the synergistic anti-tumor effect of tumor targeting, reversal of MDR and chemotherapy. Based on a fusion of these multiple mechanisms, PTX IPCNs showed a superior antitumor efficacy in mice loading A549/MDR tumor.

Drug repurposing to overcome resistance to various therapies for colorectal cancer

Emergence of novel treatment modalities provides effective therapeutic options, apart from conventional cytotoxic chemotherapy, to fight against colorectal cancer. Unfortunately, drug resistance remains a huge challenge in clinics, leading to invariable occurrence of disease progression after treatment initiation. While novel drug development is unfavorable in terms of time frame and costs, drug repurposing is one of the promising strategies to combat resistance. This approach refers to the application of clinically available drugs to treat a different disease. With the well-established safety profile and optimal dosing of these approved drugs, their combination with current cancer therapy is suggested to provide an economical, safe and efficacious approach to overcome drug resistance and prolong patient survival. Here, we review both preclinical and clinical efficacy, as well as cellular mechanisms, of some extensively studied repurposed drugs, including non-steroidal anti-inflammatory drugs, statins, metformin, chloroquine, disulfiram, niclosamide, zoledronic acid and angiotensin receptor blockers. The three major treatment modalities in the management of colorectal cancer, namely classical cytotoxic chemotherapy, molecular targeted therapy and immunotherapy, are covered in this review.

miR-21-mediated regulation of 15-hydroxyprostaglandin dehydrogenase in colon cancer

Elevated prostaglandin E₂ (PGE₂) levels are observed in colorectal cancer (CRC) patients, and this increase is associated with poor prognosis. Increased synthesis of PGE₂ in CRC has been shown to occur through COX-2-dependent mechanisms; however, loss of the PGE₂-catabolizing enzyme, 15-hydroxyprostaglandin dehydrogenase (15-PGDH, HPGD), in colonic tumors contributes to increased prostaglandin levels and poor patient survival. While loss of 15-PGDH can occur through transcriptional mechanisms, we demonstrate that 15-PGDH can be additionally regulated by a miRNA-mediated mechanism. We show that 15-PGDH and miR-21 are inversely correlated in CRC patients, with increased miR-21 levels associating with low 15-PGDH expression. 15-PGDH can be directly regulated by miR-21 through distinct sites in its 3′ untranslated region (3′UTR), and miR-21 expression in CRC cells attenuates 15-PGDH and promotes increased PGE₂ levels. Additionally, epithelial growth factor (EGF) signaling suppresses 15-PGDH expression while simultaneously enhancing miR-21 levels. miR-21 inhibition represses CRC cell proliferation, which is enhanced with EGF receptor (EGFR) inhibition. These findings present a novel regulatory mechanism of 15-PGDH by miR-21, and how dysregulated expression of miR-21 may contribute to loss of 15-PGDH expression and promote CRC progression via increased accumulation of PGE₂.

Semaphoring 4D is required for the induction of antioxidant stress and anti-inflammatory effects of dihydromyricetin in colon cancer

Semaphorin 4D (Sema4D) has been involved in cancer progression, the expression of which is associated with the poor clinical outcomes of some cancer patients. Dihydromyricetin (DMY) has antitumor potentials for different types of human cancer cells. However, the pharmacological effects of DMY on colon cancer (CC) or the regulatory effects of Sema4D on this process remain largely unknown. In the present study, we aimed to evaluate the effects of DMY on CC, and to elucidate the role of Sema4D in DMY-induced antitumor effects. DMY inhibited the proliferation and growth of Colo-205 colon cancer cells significantly in vivo and in vitro. DMY inhibited reactive oxygen species (ROS) and malondialdehyde (MDA) levels, but increased glutathione (GSH) level. Moreover, the activities of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR) and heme oxygenase 1 (HO-1) were enhanced by DMY treatment in vitro, showing strong anti-oxidative stress effect. In addition, DMY inhibited the secretion of interleukin 1β (IL-1β), interleukin-6 (IL-6), interleukin-8 (IL-8) and tumor necrosis factor (TNF-α) in the supernatant of Colo-205 culture medium. Besides, the expressions of cyclooxygenase (COX-2) and inducible nitric oxide synthase (iNOS) were suppressed by DMY in dose-dependent manners in vivo, showing potent anti-inflammatory effect. Further investigations showed that DMY suppressed the expression and secretion of Sema4D in Colo-205 cells and tissues. Interestingly, overexpression of Sema4D significantly weakened the regulatory effects of DMY on oxidative stress. Furthermore, overexpression of Sema4D significantly attenuated the anti-inflammatory effects of DMY. Collectively, we drew a conclusion that the anti-colon cancer effect of DMY was attributed to its negative modulation on oxidative stress and inflammation via suppression of Sema4D. The findings broaden the width and depth of molecular mechanisms involved in the DMY action, facilitating the development of DMY in anti-colon cancer therapies.

The cytotoxic and genotoxic effects of daidzein on MIA PaCa-2 human pancreatic carcinoma cells and HT-29 human colon cancer cells

Daidzein (DZ) has anti-inflammatory and antioxidant effects, as well as the dose-dependent inhibition effect on cancer cells. In this study, the cytotoxic and genotoxic effects of DZ on HT-29 (human colorectal adenocarcinoma cells) and MIA PaCa-2 (human pancreatic cancer cells) cell lines were determined using the XTT method and Comet assay, respectively. IC₅₀ concentrations of DZ were found to be 200 µM in both MIA PaCa-2 and HT-29 cells treated with DZ for 48 hours (h). When the cells were treated with 200 μM of DZ for 48 h, DNA damage was observed in both cell lines. DNA tail length (TL), tail moment (TM), and tail intensity (TI) increased more in MIA PaCa-2 cells treated with 200 μM of DZ than those in the control cell (untreated MIA PaCa-2 cell) group (p < 0.01). However, only DNA-TI and DNA-TM exhibited higher increases in HT-29 cells treated with 200 μM of DZ than those in the control cell (untreated HT-29 cell) group (p < 0.01). This shows that DZ has cytotoxic and genotoxic effects on both cell lines. The observed genotoxic effects of DZ still need to be confirmed in additional future studies.

Eicosanoid signaling in carcinogenesis of colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related death in the USA. It is of practical importance to identify novel therapeutic targets of CRC to develop new anti-cancer drugs and to discover novel biomarkers of CRC to develop new detection methods. Eicosanoids, which are metabolites of polyunsaturated fatty acids produced by cyclooxygenase (COX), lipoxygenase (LOX), and cytochrome P450 (CYP) enzymes, are important lipid-signaling molecules involved in the regulation of inflammation and tumorigenesis. Substantial studies have shown that the profiles of eicosanoids are deregulated in CRC, and the enzymes, metabolites, and receptors in the eicosanoid signaling cascade play critical roles in regulating colonic inflammation and colon tumorigenesis. In this review, we discuss the roles of the COX, LOX, and CYP pathways in the carcinogenesis of CRC.

Emerging cellular functions of the lipid metabolizing enzyme 15-Lipoxygenase-1

The oxygenation of polyunsaturated fatty acids such as arachidonic and linoleic acid through lipoxygenases (LOXs) and cyclooxygenases (COXs) leads to the production of bioactive lipids that are important both in the induction of acute inflammation and its resolution. Amongst the several isoforms of LOX that are expressed in mammals, 15-LOX-1 was shown to be important both in the context of inflammation, being expressed in cells of the immune system, and in epithelial cells where the enzyme has been shown to crosstalk with a number of important signalling pathways. This review looks into the latest developments in understanding the role of 15-LOX-1 in different disease states with emphasis on the emerging role of the enzyme in the tumour microenvironment as well as a newly re-discovered form of cell death called ferroptosis. We also discuss future perspectives on the feasibility of use of this protein as a target for therapeutic interventions.

Indoleamine-2,3-dioxygenase 1/cyclooxygenase 2 expression prediction for adverse prognosis in colorectal cancer

AIM

To evaluate indoleamine-2,3-dioxygenase 1/cyclooxygenase 2 (IDO1/COX2) expression as an independent prognostic biomarker for colorectal cancer (CRC) patients.

METHODS

We retrospectively studied the medical records of 95 patients who received surgical resection from August 2008 to January 2010. All patients were randomly assigned to adjuvant treatment with or without celecoxib groups after surgery. We performed standard immunohistochemistry to assess the expression levels of IDO1/COX2 and evaluated the correlation of IDO1/COX2 with clinicopathological factors and overall survival (OS) outcomes.

RESULTS

The expression of nuclear IDO1 was significantly correlated with body mass index (P < 0.001), and IDO1 expression displayed no association with sex, age, tumor differentiation, T stage, N stage, carcinoembryonic antigen, cancer antigen 19-9, CD3+ and CD8+ tumor infiltrating lymphocytes, and COX2. In univariate analysis, we found that nuclear IDO1 (P = 0.039), nuclear/cytoplasmic IDO1 [hazard ratio (HR) = 2.044, 95% confidence interval (CI): 0.871-4.798, P = 0.039], nuclear IDO1/COX2 (HR = 3.048, 95%CI: 0.868-10.7, P = 0.0049) and cytoplasmic IDO1/COX2 (HR = 2.109, 95%CI: 0.976-4.558, P = 0.022) all yielded significantly poor OS outcomes. Nuclear IDO1 (P = 0.041), nuclear/cytoplasmic IDO1 (HR = 3.023, 95%CI: 0.585-15.61, P = 0.041) and cytoplasmic IDO1/COX2 (HR = 2.740, 95%CI: 0.764-9.831, P = 0.038) have significantly poor OS outcomes for the CRC celecoxib subgroup. In our multivariate Cox model, high coexpression of cytoplasmic IDO1/COX2 was found to be an independent predictor of poor outcome in CRC (HR = 2.218, 95%CI: 1.011-4.48, P = 0.047) and celecoxib subgroup patients (HR = 3.210, 95%CI: 1.074-9.590, P = 0.037).

CONCLUSION

Our results showed that cytoplasmic IDO1/COX2 coexpression could be used as an independent poor predictor for OS in CRC.

A drug combination targeting hypoxia induced chemoresistance and stemness in glioma cells

Hypoxia is a characteristic of solid tumors especially Glioblastoma and is critical to chemoresistance. Cancer stem cells present in hypoxic niches are known to be a major cause of the progression, metastasis and relapse. We tried to identify synergistic combinations of drugs effective in both hypoxia and normoxia in tumor cells as well as in cancer stem cells. Since COX-2 is over-expressed in subset of glioblastoma and is also induced in hypoxia, we studied combinations of a prototype Cyclooxygenase (COX-2) inhibitor, NS-398 with various drugs (BCNU, Temozolomide, 2-Deoxy-D-glucose and Cisplatin) for their ability to abrogate chemoresistance under both severe hypoxia (0.2% O₂) and normoxia (20% O₂) in glioma cells. The only effective combination was of NS-398 and BCNU which showed a synergistic effect in both hypoxia and normoxia. This synergism was evident at sub-lethal doses for either of the single agent. The effectiveness of the combination resulted from increased pro- apoptotic and decreased anti-apoptotic molecules and increased caspase activity. PGE₂ levels, a manifestation of COX-2 activity were increased during hypoxia, but were reduced by the combination during both hypoxia and normoxia. The combination reduced the levels of epithelial-mesenchymal transition (EMT) markers. It also resulted in a greater reduction of cell migration. While single drugs could reduce the number of gliomaspheres, the combination successfully abrogated their formation. The combination also resulted in a greater reduction of the cancer stem cell marker CD133. This combination could be a prototype of possible therapy in a tumor with a high degree of hypoxia like glioma.

Repurposing the anti-malarial drug dihydroartemisinin suppresses metastasis of non-small-cell lung cancer via inhibiting NF-κB/GLUT1 axis

Non-small-cell lung cancer (NSCLC) is an aggressive malignancy and long-term survival remains unsatisfactory for patients with metastatic and recurrent disease. Repurposing the anti-malarial drug dihydroartemisinin (DHA) has been proved to possess potent antitumor effect on various cancers. However, the effects of DHA in preventing the invasion of NSCLC cells have not been studied. In the present study, we determined the inhibitory effects of DHA on invasion and migration and the possible mechanisms involved using A549 and H1975 cells. DHA inhibited in vitro migration and invasion of NSCLC cells even in low concentration with little cytotoxicity. Additionally, low concentration DHA also inhibited Warburg effect in NSCLC cells. Mechanically, DHA negatively regulates NF-κB signaling to inhibit the GLUT1 translocation. Blocking the NF-κB signaling largely abolishes the inhibitory effects of DHA on the translocation of GLUT1 to the plasma membrane and the Warburg effect. Furthermore, GLUT1 knockdown significantly decreased the inhibition of invasion, and migration by DHA. Our results suggested that DHA can inhibit metastasis of NSCLC by targeting glucose metabolism via inhibiting NF-κB signaling pathway and DHA may deserve further investigation in NSCLC treatment.

Targeted photodynamic therapy as potential treatment modality for the eradication of colon cancer and colon cancer stem cells

Colorectal cancer is commonly treated by tumour resection, as chemotherapy and radiation have proven to be less effective, especially if the tumour has metastasized. Resistance to therapies occurs in almost all patients with colorectal cancer, especially in those with metastatic tumours. Cancer stem cells have the ability to self-renew, and their slow rate of cycling enhances resistance to treatment and increases the likelihood of tumour recurrence. Most metastatic tumours are unable to be surgically removed, thus creating a need for treatment modalities that target cancers directly and destroy cancer stem cells. Photodynamic therapy involves a photosensitizer that when exposed to a light source of a particular wavelength becomes excited and produces a form of oxygen that kills cancer cells. Photodynamic therapy is currently being investigated as a treatment modality for colorectal cancer, and new studies are exploring enhancing photodynamic therapy efficacy with the aid of drug carriers and immune conjugates. These modifications could prove effective in targeting cancer stem cells that are thought to be resistant to photodynamic therapy. In order for photodynamic therapy to be an effective treatment in colorectal cancer, it requires treatment of both primary tumours and the metastatic secondary disease that is caused by colon cancer stem cells. This review focuses on current photodynamic therapy treatments available for colorectal cancer and highlights proposed actively targeted photosynthetic drug uptake mechanisms specifically mediated towards colon cancer stem cells, as well as identify the gaps in research which need to be investigated in order to develop a combinative targeted photodynamic therapy regime that can effectively control colorectal cancer primary and metastatic tumour growth by eliminating colon cancer stem cells.

Sox2 modulates motility and enhances progression of colorectal cancer via the Rho-ROCK signaling pathway

Sox2 (Sry-box2) is essential for a variety of stem cells and is also expressed in colorectal cancer (CRC). However, the underlying mechanism by which Sox2 enhances CRC progression remains unclear. In the present study, we show that elevated Sox2 expression is significantly correlated with poor clinical prognosis. CRC is phenotypically heterogeneous, and harbors several subtypes of cancer cells. Elevated Sox2 expression was always detected in rounded-shape cells, which co-located to poorly differentiated regions, the invasive frontier and metastatic lesions. Knockdown of Sox2 in CRC cells not only decreased the number of round-shaped cells, but also suppressed cell migration, invasion as well as attenuated colony forming capacity and tumorigenicity. By contrast, overexpression of Sox2 in CRC cells was associated with up-regulation of multidrug resistance genes and accelerated CRC progression. Moreover, Sox2 conferred activation of Rho-ROCK signaling, whereas inhibition of ROCK signaling decreased cell migration, invasion, colony formation and self-renewal of CRC. Our results reveal that CRC is phenotypically and functionally heterogeneous. Elevated Sox2 expression activates the Rho-ROCK pathway, which in turn changes cell morphology and promotes cell migration and progression.

Celecoxib normalizes the tumor microenvironment and enhances small nanotherapeutics delivery to A549 tumors in nude mice

Barriers presented by the tumor microenvironment including the abnormal tumor vasculature and interstitial matrix invariably lead to heterogeneous distribution of nanotherapeutics. Inspired by the close association between cyclooxygenase-2 (COX-2) and tumor-associated angiogenesis, as well as tumor matrix formation, we proposed that tumor microenvironment normalization by COX-2 inhibitors might improve the distribution and efficacy of nanotherapeutics for solid tumors. The present study represents the first time that celecoxib, a special COX-2 inhibitor widely used in clinics, was explored to normalize the tumor microenvironment and to improve tumor nanotherapeutics delivery using a human-derived A549 tumor xenograft as the solid tumor model. Immunofluorescence staining of tumor slices demonstrated that oral celecoxib treatment at a dose of 200 mg/kg for two weeks successfully normalized the tumor microenvironment, including tumor-associated fibroblast reduction, fibronectin bundle disruption, tumor vessel normalization, and tumor perfusion improvement. Furthermore, it also significantly enhanced the in vivo accumulation and deep penetration of 22-nm micelles rather than 100-nm nanoparticles in tumor tissues by in vivo imaging and distribution experiments and improved the therapeutic efficacy of paclitaxel-loaded micelles in tumor xenograft-bearing mouse models in the pharmacodynamics experiment. As celecoxib is widely and safely used in clinics, our findings may have great potential in clinics to improve solid tumor treatment.

C-Phycocyanin: Cellular targets, mechanisms of action and multi drug resistance in cancer

C-Phycocyanin (C-PC) has been shown to be promising in cancer treatment; however, although several articles detailing this have been published, its main mechanisms of action and its cellular targets have not yet been defined, nor has a detailed exploration been conducted of its role in the resistance of cancer cells to chemotherapy, rendering clinical use impossible. From our extensive examination of the literature, we have determined as our main hypothesis that C-PC has no one specific target, but rather acts on the membrane, cytoplasm, and nucleus with diverse mechanisms of action. We highlight the cell targets with which C-PC interacts (the MDR1 gene, cytoskeleton proteins, and COX-2 enzyme) that make it capable of killing cells resistant to chemotherapy. We also propose future analyses of the interaction between C-PC and drug extrusion proteins, such as ABCB1 and ABCC1, using in silico and in vitro studies.

Correlations of IGF-1R and COX-2 Expressions with Ras and BRAF Genetic Mutations, Clinicopathological Features and Prognosis of Colorectal Cancer Patients

This case-control study aims to investigate the correlations of insulin-like growth factor receptor 1 (IGF-1R) and cyclooxygenase 2 (COX-2) expressions with Ras and BRAF genetic mutations, clinicopathological features and prognosis of colorectal cancer (CRC) patients. A total of 213 CRC patients (case group) and 200 healthy individuals (control group) were selected from our hospital. Ras (K-Ras/N-Ras) and BRAF genetic mutations were detected by direct sequencing. The positive expression rates of IGF-IR and COX-2 in CRC and normal tissues were detected using immunohistochemistry. RT-qPCR and Western blotting were applied to detect the mRNA and protein expressions of IGF-IR and COX-2 in CRC tissues and normal tissues. Total mutation rate of N-Ras, BRAF and K-Ras in case group were 5.2%, 12.2% and 47.4%, respectively. The expressions of IGF-IR and COX-2 were higher in CRC tissues with Ras and BRAF mutations than in those without. CRC tissues with Ras mutation showed higher COX-2 expression than those with BRAF mutation. IGF-IR and COX-2 expressions were correlated to infiltration degree, lymphatic metastasis (in CRC tissues with and without Ras and BRAF mutations), and Dukes stages (only in CRC tissues with Ras and BRAF mutations). CRC patients with negative expressions of IGF-IR and COX-2 had significantly higher accumulative survival rate and longer mean survival duration than those with positive expressions of IGF-IR and COX-2. These findings indicate that IGF-1R and COX-2 expressions may be associated with Ras and BRAF genetic mutations, clinicopathological feature and prognosis of CRC patients.

Phytochemical Investigations of Three Rhodocodon (Hyacinthaceae Sensu APG II) Species

The genus Rhodocodon (Hyacinthaceae sensu APG II) is endemic to Madagascar, and its phytochemistry has not been described previously. The phytochemistry of three species in this genus has been investigated, and eight compounds, including three bufadienolides (compounds 1, 4, and 5), a norlignan (2), and four homoisoflavonoids (compounds 3 and 6-8), have been isolated and identified. Compounds 1-3 and 6-8 have not been described previously. The COX-2 inhibitory activity of compound 6 and compound 7 acetate (compound 7A) was investigated on isolated colorectal cancer cells. Compounds 6 and 7A inhibited COX-2 by 10% and 8%, respectively, at a concentration of 12.5 μM compared to 12% for 1 mM aspirin (the positive control).

The Role of Cyclooxygenase-2 in Colorectal Carcinogenesis

Colorectal cancer is a major worldwide health care problem that accounts for 1 million new cases each year. The risk factors for this disease include hereditary factors, environmental agents, and inflammatory stimuli that affect the gastrointestinal tract. Among these risk factors, cyclooxygenase-2 (COX-2) is one of the major players in the progression of colorectal cancer; however, the detailed mechanism of its role in causing colorectal cancer is still not well understood. In addition, the role of COX-2 signaling through the interaction in the epithelial and stromal compartments on colorectal carcinogenesis has not been fully illustrated. In the present review, we provide published evidence to demonstrate that (1) COX-2 signaling plays a major role in the progression of colorectal cancer, (2) activation of COX-2 in the stromal compartment also contributes to colorectal carcinogenesis, and (3) inhibition of COX-2 signaling by COX-2 inhibitors might be an effective method to control colorectal cancer. We have also summarized recent advances and insights from mechanistic studies of colorectal cancer to help prevent and control this deadly disease and provide our opinion regarding the importance of risk reduction and disease prevention for colorectal cancer.

Aspirin in combination with TACE in treatment of unresectable HCC: a matched-pairs analysis

Transarterial chemoembolization (TACE) is the principal therapy for unresectable hepatocellular carcinoma (HCC). However, its efficacy is currently limited owing to tumor progression or treatment failure. It has been shown that aspirin reduces the incidence of multiple malignant tumors including HCC and plays a synergistic role with chemotherapy in the treatment of colon cancer. Therefore, we aimed to investigate the adjuvant effect of aspirin on patients with unresectable HCC who underwent TACE therapy. A retrospective matched-pairs analysis was performed to evaluate the efficacy of aspirin in combination with TACE therapy. A total of 120 patients with HCC, including 60 patients treated with aspirin for treatment of cardiovascular disease, transient ischemic attack, and arthritis, and 60 paired matching HCC patients without aspirin treatment in the same period, were enrolled. Compared with non-aspirin users, patients treated with aspirin showed improved OS (P = 0.050). Specifically, patients treated with a full dose of aspirin showed prolonged OS (P = 0.027), which was an independent factor associated with OS in multivariate analysis (hazard ratio 0.498, 95% confidence interval 0.280-0.888, P = 0.018). Aspirin in combination with TACE might improve OS in patients with unresectable HCC. Thus, the impact of aspirin on patients with HCC warrants further investigation prospectively.

Calcium Alginate and Calcium Alginate-Chitosan Beads Containing Celecoxib Solubilized in a Self-Emulsifying Phase

In this work alginate and alginate-chitosan beads containing celecoxib solubilized into a self-emulsifying phase were developed in order to obtain a drug delivery system for oral administration, able to delay the drug release in acidic environment and to promote it in the intestinal compartment. The rationale of this work was linked to the desire to improve celecoxib therapeutic effectiveness reducing its gastric adverse effects and to favor its use in the prophylaxis of colon cancer and as adjuvant in the therapy of familial polyposis. The systems were prepared by ionotropic gelation using needles with different diameters (400 and 600 μm). Morphology, particle size, swelling behavior, and in vitro drug release performance of the beads in aqueous media with different pH were investigated. The experimental results demonstrated that the presence of chitosan in the formulation caused an increase of the mechanical resistance of the bead structure and, as a consequence, a limitation of the bead swelling ability and a decrease of the drug release rate at neutral pH. Alginate-chitosan beads could be a good tool to guarantee a celecoxib colon delivery.

Synergistic growth inhibitory effect of deracoxib with doxorubicin against a canine mammary tumor cell line, CMT-U27

Cyclooxygenase (COX) inhibitors have been shown to exert anti-angiogenic and anti-tumor activities on many types of malignant tumors. These anticancer properties make it worthwhile to examine the possible benefit of combining COX inhibitors with other anti-cancer agents. In the present study, we evaluated the potential of deracoxib (DER) in potentiating antitumor activity of doxorubicin (DOX) in canine mammary carcinoma cells (CMT-U27). DER (50–250 µM) enhanced the antiproliferative activity of DOX by reducing the IC₅₀ (approximately 3- to 3.5 fold). Interaction analysis of the data showed that combinations of DOX at 0.9 µM with DER (100–250 µM) produced synergism in the CMT-U27 cell line, with a ratio index ranging from 1.98 to 2.33. In additional studies identifying the mechanism of observed synergistic effect, we found that DER strongly potentiated DOX-caused G₀/G₁ arrest in cell cycle progression. Also, DER (100–250 µM) augmented apoptosis induction with approximately 1.35- and 1.37- fold increases in apoptotic response caused by DOX in the cells. DER enhanced the antiproliferative effect of DOX in conjunction with induction of apoptosis by modulation of Bcl-2 expression and changes in the cell cycle of the CMT-U27 cell line. Although the exact molecular mechanism of the alterations in the cell cycle and apoptosis observed with DER and DOX combinations require further investigations, the results suggest that the synergistic effect of DOX and DER combinations in CMT therapy may be achieved at relatively lower doses of DOX with lesser side effects. Therefore, combining DER with DOX may prove beneficial in the clinical treatment of canine mammary cancer.

Poly-γ-glutamic acid induces apoptosis via reduction of COX-2 expression in TPA-induced HT-29 human colorectal cancer cells

Poly-γ-glutamic acid (PGA) is one of the bioactive compounds found in cheonggukjang, a fast-fermented soybean paste widely utilized in Korean cooking. PGA is reported to have a number of beneficial health effects, and interestingly, it has been identified as a possible anti-cancer compound through its ability to promote apoptosis in cancer cells, although the precise molecular mechanisms remain unclear. Our findings demonstrate that PGA inhibits the pro-proliferative functions of the phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA), a known chemical carcinogen in HT-29 human colorectal cancer cells. This inhibition was accompanied by hallmark apoptotic phenotypes, including DNA fragmentation and the cleavage of poly (ADP-ribose) polymerase (PARP) and caspase 3. In addition, PGA treatment reduced the expression of genes known to be overexpressed in colorectal cancer cells, including cyclooxygenase 2 (COX-2) and inducible nitric oxide synthase (iNOS). Lastly, PGA promoted activation of 5' adenosine monophosphate-activated protein (AMPK) in HT-29 cells. Taken together, our results suggest that PGA treatment enhances apoptosis in colorectal cancer cells, in part by modulating the activity of the COX-2 and AMPK signaling pathways. These anti-cancer functions of PGA make it a promising compound for future study.

Anti-inflammatory activity of polyphenolics from açai (Euterpe oleracea Martius) in intestinal myofibroblasts CCD-18Co cells

This is the first time that the anti-inflammatory activities of açai polyphenols relevant to intestinal inflammation were demonstrated in colon fibroblasts cells.

Cancer subclonal genetic architecture as a key to personalized medicine

The future of personalized oncological therapy will likely rely on evidence-based medicine to integrate all of the available evidence to delineate the most efficacious treatment option for the patient. To undertake evidence-based medicine through use of targeted therapy regimens, identification of the specific underlying causative mutation(s) driving growth and progression of a patient's tumor is imperative. Although molecular subtyping is important for planning and treatment, intraclonal genetic diversity has been recently highlighted as having significant implications for biopsy-based prognosis. Overall, delineation of the clonal architecture of a patient's cancer and how this will impact on the selection of the most efficacious therapy remain a topic of intense interest.

Induction of apurinic endonuclease 1 overexpression by endoplasmic reticulum stress in hepatoma cells

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide with poor prognosis due to resistance to conventional chemotherapy and limited efficacy of radiotherapy. Previous studies have noted the induction of endoplasmic reticulum stress or apurinic endonuclease 1 (APE1) expression in many tumors. Therefore, the aim of this study was to investigate the relationship between endoplasmic reticulum (ER stress) and APE1 in hepatocellular carcinoma. Here we investigate the expression of APE1 during ER stress in HepG2 and Huh-7 cell lines. Tunicamycin or brefeldin A, two ER stress inducers, increased APE1 and GRP78, an ER stress marker, expression in HepG2 and Huh-7 cells. Induction of APE1 expression was observed through transcription level in response to ER stress. APE1 nuclear localization during ER stress was determined using immunofluorescence assays in HepG2 cells. Furthermore, expression of Hepatitis B virus pre-S2∆ large mutant surface protein (pre-S2∆), an ER stress-induced protein, also increased GRP78 and APE1 expression in the normal hepatocyte NeHepLxHT cell line. Similarly, tumor samples showed higher expression of APE1 in ER stress-correlated liver cancer tissue in vivo. Our results demonstrate that ER stress and HBV pre-S2∆ increased APE1 expression, which may play an important role in resistance to chemotherapeutic agents or tumor development. Therefore, these data provide an important chemotherapeutic strategy in ER stress and HBV pre-S2∆-associated tumors.

Characterization of the inflammatory microenvironment and identification of potential therapeutic targets in wilms tumors

The role of inflammation in cancer has been reported in various adult malignant neoplasms. By contrast, its role in pediatric tumors has not been as well studied. In this study, we have identified and characterized the infiltration of various inflammatory immune cells as well as inflammatory markers in Wilms tumor (WT), the most common renal malignancy in children. Formalin-fixed paraffin-embedded blocks from tumors and autologous normal kidneys were immunostained for inflammatory immune cells (T cells, B cells, macrophages, neutrophils, and mast cells) and inflammatory markers such as cyclooxygenase-2 (COX-2), hypoxia-inducible factor 1α, phosphorylated STAT3, phosphorylated extracellular signal-related kinases 1 and 2, inducible nitric oxide synthase, nitrotyrosine, and vascular endothelial growth factor expression. Overall, we found that there was predominant infiltration of tumor-associated macrophages in the tumor stroma where COX-2 was robustly expressed. The other tumor-associated inflammatory markers were also mostly localized to tumor stroma. Hence, we speculate that COX-2-mediated inflammatory microenvironment may be important in WT growth and potential therapies targeting this pathway may be beneficial and should be tested in clinical settings for the treatment of WTs in children.

Immunohistochemical expression of potential therapeutic targets in canine thyroid carcinoma

BACKGROUND

Thyroid carcinoma is a common endocrine tumor in the dog. Local invasive growth frequently precludes surgical excision and, in up to 38% of dogs, the tumor has already metastasized by the time of diagnosis. Therefore, it is important to investigate new treatment modalities that may be useful for the large number of dogs with inoperable tumors or metastatic disease.

HYPOTHESIS/OBJECTIVES

To investigate the immunohistochemical expression of potential therapeutic targets in canine thyroid tumors.

ANIMALS

74 dogs with thyroid neoplasia.

METHODS

Immunohistochemistry was performed for thyroglobulin, calcitonin, vascular endothelial growth factor (VEGF), p53, cycloxygenase-2 (cox-2), and P-glycoprotein (P-gp).

RESULTS

Fifty-four (73%) tumors were classified as follicular cell thyroid carcinomas (FTCs) and 20 (27%) as medullary thyroid carcinomas (MTCs). Eighty percent of FTCs and all MTCs had a high percentage (76-100%) of neoplastic cells immunopositive for VEGF. Thirteen percent of FTCs and 50% of MTCs expressed cox-2. Seven percent of FTCs and 70% of MTCs expressed P-gp. No tumor was immunopositive for p53 expression. Expression of VEGF (P = .034), cox-2 (P = .013), and P-gp (P < .001) was significantly higher in MTCs compared to FTCs.

CONCLUSIONS AND CLINICAL IMPORTANCE

VEGF is a potential therapeutic target in both FTC and MTC in dogs. Cox-2 and P-gp may be useful molecular targets in canine MTC.

The discovery and development of cyclooxygenase-2 inhibitors as potential anticancer therapies

INTRODUCTION

In the past, clinical studies had demonstrated that aspirin and NSAIDs reduce the risk of colorectal cancer. After the discovery of selective prostaglandin-endoperoxide synthase 2 (PTGS2) inhibitors, the further beneficial effects of celecoxib and some other related structures (coxibs) have been demonstrated in both in vivo and in vitro studies.

AREAS COVERED

The authors illustrate the role of prostaglandins following the overexpression of PTGS2 (COX-2) in signaling pathways. The authors elucidate the role of coxibs in cell proliferation, apoptosis, angiogenesis and multi-drug resistance and discuss the molecular mechanisms involved. The authors also present the strong evidence related to the usefulness of coxibs in several cancer cell lines.

EXPERT OPINION

There have been a number of PTGS2 (COX-2) selective inhibitors suggested as potential anticancer therapies. In recent years, the development of nanotechnology has also had an impact on chemotherapy. Indeed, nanoparticles of cytotoxic drug carriers have demonstrated potential through their accumulation in cancer cells, and targeting these nanoparticles has been under evaluation. This area could be opened up for coxib development as they are potentially important targets in cancer cells. Further research using celecoxib as a co-drug with PTGS2-overexpressed and PTGS2-independent cancer is still needed.