Up-regulation of p53 and mitochondrial signaling pathway in apoptosis by a combination of COX-2 inhibitor, Celecoxib and Dolastatin 15, a marine mollusk linear peptide in experimental colon carcinogenesis

Decreased cyclooxygenase-2 associated with impaired megakaryopoiesis and thrombopoiesis in primary immune thrombocytopenia

BACKGROUND

Cyclooxygenase (COX)-2 is a rate-limiting enzyme in the biosynthesis of prostanoids, which is mostly inducible by inflammatory cytokines. The participation of COX-2 in the maturation of megakaryocytes has been reported but barely studied in primary immune thrombocytopenia (ITP).

METHODS

The expressions of COX-2 and Caspase-1, Caspase-3 and Caspase-3 p17 subunit in platelets from ITP patients and healthy controls (HC), and the expressions of COX-2 and CD41 in bone marrow (BM) of ITP patients were measured and analyzed for correlations. The effects of COX-2 inhibitor on megakaryopoiesis and thrombopoiesis were assessed by in vitro culture of Meg01 cells and murine BM-derived megakaryocytes and in vivo experiments of passive ITP mice.

RESULTS

The expression of COX-2 was decreased and Caspase-1 and Caspase-3 p17 were increased in platelets from ITP patients compared to HC. In platelets from ITP patients, the COX-2 expression was positively correlated with platelet count and negatively correlated to the expression of Caspase-1. In ITP patients BM, the expression of CD41 was positively correlated with the expression of COX-2. COX-2 inhibitor inhibited the count of megakaryocytes and impaired the maturation and platelet production in Meg01 cells and bone marrow-derived megakaryocytes. COX-2 inhibitor aggravated thrombocytopenia and damaged megakaryopoiesis in ITP murine model.

CONCLUSION

COX-2 plays a vital role in the physiologic and pathologic conditions of ITP by intervening the survival of platelets and impairing the megakaryopoiesis and thrombopoiesis of megakaryocytes.

Marine Compounds, Mitochondria, and Malignancy: A Therapeutic Nexus

The marine environment is important yet generally underexplored. It contains new sources of functional constituents that can affect various pathways in food processing, storage, and fortification. Bioactive secondary metabolites produced by marine microorganisms may have significant potential applications for humans. Various components isolated from disparate marine microorganisms, including fungi, microalgae, bacteria, and myxomycetes, showed considerable biological effects, such as anticancer, antioxidant, antiviral, antibacterial, and neuroprotective activities. Growing studies are revealing that potential anticancer effects of marine agents could be achieved through the modulation of several organelles. Mitochondria are known organelles that influence growth, differentiation, and death of cells via influencing the biosynthetic, bioenergetic, and various signaling pathways related to oxidative stress and cellular metabolism. Consequently, mitochondria play an essential role in tumorigenesis and cancer treatments by adapting to alterations in environmental and cellular conditions. The growing interest in marine-derived anticancer agents, combined with the development and progression of novel technology in the extraction and cultures of marine life, led to revelations of new compounds with meaningful pharmacological applications. This is the first critical review on marine-derived anticancer agents that have the potential for targeting mitochondrial function during tumorigenesis. This study aims to provide promising strategies in cancer prevention and treatment.

Recent Updates on Marine Cancer-Preventive Compounds

The natural compounds derived from marine organisms often exhibit unique chemical structures and potent biological activities. Cancer-preventive activity is one of the rather new activities that has emerged and been extensively studied over the last decades. This review summarizes the recent updates on the marine chemopreventive compounds covering the relevant literature published in 2013-2021 and following the previous comprehensive review by Stonik and Fedorov (Marine Drugs 2014, 12, 636-671). In the current article, only the molecules having an effect on malignant transformation (or related pathway and molecules), cancer stem cells, or carcinogen-induced in vivo tumor development were considered to be "true" cancer-preventive compounds and were, therefore, reviewed. Additionally, particular attention has been given to the molecular mechanisms of chemoprevention, executed by the reported marine compounds.

Imatinib exhibit synergistic pleiotropy in the prevention of colorectal cancer by suppressing proinflammatory, cell survival and angiogenic signaling

Recent global incidences and mortality rates have placed colorectal cancer (CRC) at third and second positions, respectively, among both sexes of all ages. Resistance during chemotherapy is a big problem in the treatment and disease-free survival of CRC patients. Discovery of new anticancer drug(s) is a time taking process and therefore, invites studies for repurposing the known therapeutics. The present study was conceived to analyze the anticancer role of Imatinib in experimental CRC at early stages. Different experimental procedures e.g. tumor incidences or histoarchitectural changes, gene and protein expression analysis, estimations of intracellular calcium, ROS, mitochondrial membrane potential, apoptotic index and molecular docking was performed to support the hypothesis. It was observed that Imatinib could function as an immunomodulator by breaking the feed-back loop between the proinflammatory cytokines (IL-1β and TNF-α) and transcription factors (NF-κB, Jak3/Stat3) knowingly involved in increased cell proliferation during tumorigenesis via activating different intracellular signaling. Also, Imatinib could independently deregulate the other cell survival and proliferation signaling e.g. PI3-K/Akt/mTOR, Wnt/β-catenin and MAPK. Proinflammatory cytokines orchestrated intracellular signaling also involve angiogenic factors to be upregulated during CRC which were also seemed to be independently suppressed by Imatinib. Restoration of physiological apoptosis by increasing the release of intracellular calcium to generate ROS thereby reducing the mitochondrial membrane potential for the release of cytochrome c and activation of caspase-3 was also reported with Imatinib administration. Thus, it may be suggested that Imatinib show synergistic pleiotropy in suppressing the interlinked tumorigenic signaling pathways independently.

Celecoxib inhibits the epithelial-to-mesenchymal transition in bladder cancer via the miRNA-145/TGFBR2/Smad3 axis

Celecoxib, a selective cyclooxygenase-2 inhibitor, has chemo-preventive activity against different cancer types, including bladder cancer (BC). However, the mechanisms by which celecoxib exerts its cancer preventative effects have yet to be completely understood. In the present study, the effect of celecoxib on the epithelial-to-mesenchymal transition (EMT) of BC cells and its potential molecular mechanisms were investigated. The results of the present study demonstrated that celecoxib inhibited the proliferation, migration, invasion and EMT of BC cells. Further investigation of the underlying mechanism revealed that celecoxib inhibited EMT by upregulating microRNA (miR)-145 and downregulating the expression of transforming growth factor β receptor 2 and SMAD family member 3. Furthermore, the combination of celecoxib with miR-145 mimics demonstrated an additive migration and invasion-inhibitory effect in BC cell lines.

Prognostic Value of Accumulative Expression of COX-2 and p53 in Small and Diffuse Large B Cell Lymphoma

Cyclooxygenase-2 (COX-2) plays an important role in carcinogenesis, which catalyzes the conversion of arachidonic acid into prostaglandins. P53 is a tumor suppressor gene that contributes to apoptosis and cell cycle control. There is functional interaction between p53 and COX-2, which lead to abrogation of apoptosis and progression of malignancy. To assess the relationship between COX-2, p53 expression and the clinicopathololgic features in SLL and DLBCL. We immunohistochemically examined the expression of COX-2 and p53 in non-neoplastic lymphoid cells, lymph nodal low-grade (50 cases of SLL), intermediate and high-grade lymphomas (100 cases of DLBCL) and their corresponding bone marrow specimens. The expression of COX-2 and p53 was absent in the in non-neoplastic lymphoid cells. In contrast, their expression values increased progressively with the advancing grade of lymphoma (p < 0.001). COX-2 expression was significantly associated with advanced disease stage, high-grade lymphomas, and disease relapse and p53 expression. The p53was detected in 64.5% in patients positive for COX-2. The expressions of COX-2 and p53 proteins, were significantly associated with shorter overall-survival and progression free survival. Here we report up-regulation of COX-2and p53 protein expression in SLL and DLBCL indicating their interactive involvement in the pathogenesis of lymphoma. Our data provide a rationale for further investigation of COX-2 expression in lymphomas for potential prognostic, chemopreventive and chemotherapeutic purposes.

Prophylactic intervention of probiotics (L.acidophilus, L.rhamnosus GG) and celecoxib modulate Bax-mediated apoptosis in 1,2-dimethylhydrazine-induced experimental colon carcinogenesis

BACKGROUND

Colorectal cancer has been found to be attenuated either with prophylactic manipulation of gut microbiome with probiotics or celecoxib, a non-steroidal anti-inflammatory drug mainly by suppressing early pro-carcinogenic markers in various experimental studies. Therefore, the present study was designed to assess the prophylactic potential of combinatorial administration of probiotics (Lactobacillus rhamnosus GG, Lactobacillus acidophilus) and celecoxib in experimental colon carcinogenesis.

METHODS

Six groups of Spraugue Dawely rats received probiotics L.rhamnosus GG or/and L.acidophilus in combination with celecoxib one week prior to the inducement of tumor by 1,2-dimethylhydrazine (DMH) and the treatment continued for 18 weeks. Prophylactic potentials of probiotics and celecoxib were determined by employing various methods such as tumor incidence, tumor burden, tumor multiplicity, apoptosis, caspase activity, expression of proto-oncogene K-ras and tumor suppressor p53 gene in colonic tumors.

RESULTS

Interestingly, it was found that one week prior supplementation of both probiotics and celecoxib reduced tumor burden, tumor multiplicity, down-regulated the expression of anti-apoptotic Bcl-2, proto-oncogene K-ras and up-regulated pro-apoptotic Bax as well as tumor suppressor p53 in L.rhamnosus GG + celecoxib+DMH animals compared with counter controls and DMH-treated.

CONCLUSIONS

It can be concluded that such combinatorial approach may be useful in reducing the burden and severity of disease in highly susceptible individuals but needs to be validated clinically.

DBA-induced caspase-3-dependent apoptosis occurs through mitochondrial translocation of cyt-c in the rat hippocampus

Dibromoacetic acid (DBA), a by-product of disinfection, develops in drinking water during chlorination or ozonation processes. Water intake is the main source of DBA exposure in humans, which is potentially neurotoxic. The present study investigated the neurotoxic effects of DBA by assessing the behavioral and biochemical characteristics of Sprague Dawley rats intragastrically treated with DBA at concentrations of 20, 50 and 125 mg kg^-1 body weight for 28 consecutive days. The results indicated that animal weight gain and food consumption were not significantly affected by DBA. However, shuttle box tests showed increases in mistake frequency and reaction latency between the control and high-dose group. We found significant changes in hippocampal neurons by histomorphological observation. Additionally, biochemical analysis indicated enhanced production of reactive oxygen species (ROS) resulting in disruption of cellular antioxidant defense systems including decreased mitochondrial superoxide dismutase (SOD) activity and release of cytochrome c (cyt-c) from mitochondria into the cytosol, which can induce neuronal apoptosis. Furthermore, the increase of cyt-c in the cytosol enhanced caspase-3 and caspase-9 activity, which was confirmed by poly ADP-ribose polymerase-1 (PARP-1) cleavage to its signature fragment of 85 kDa and decreased levels of protein kinase C-δ (PKC-δ) in the hippocampus. Meanwhile, DBA treatment caused differential modulation of apoptosis-associated proteins and mRNAs for phosphorylated apoptosis signal regulating kinase 1 (p-ASK-1), phosphorylated c-jun N-terminal kinase (p-JNK), cyt-c, Bax, Bcl-2, caspase-9 and cleaved caspase-3 accompanied by DNA damage. Taken together, these data indicate that DBA may induce neurotoxicity via caspase-3-dependent apoptosis involving mitochondrial translocation of cyt-c in the rat hippocampus.

Downregulation of PI3-K/Akt/PTEN pathway and activation of mitochondrial intrinsic apoptosis by Diclofenac and Curcumin in colon cancer

Phosphatidylinositol 3-kinase (PI3-K)/PTEN/Akt signaling is over activated in various tumors including colon cancer. Activation of this pathway regulates multiple biological processes such as apoptosis, metabolism, cell proliferation, and cell growth that underlie the biology of a cancer cell. In the present study, the chemopreventive effects have been observed of Diclofenac, a preferential COX-2 inhibitory non-steroidal anti-inflammatory drugs, and Curcumin, a natural anti-inflammatory agent, in the early stage of colorectal carcinogenesis induced by 1,2-dimethylhydrazine dihydrochloride in rats. The tumor-promoting role of PI3-K/Akt/PTEN signal transduction pathway and its association with anti-apoptotic family of proteins are also observed. Both Diclofenac and Curcumin downregulated the PI3-K and Akt expression while promoting the apoptotic mechanism. Diclofenac and Curcumin administration significantly increased the expression of pro-apoptotic Bcl-2 family members (Bad and Bax) while decreasing the anti-apoptotic Bcl-2 protein. An up-regulation of cysteine protease family apoptosis executioner, such as caspase-3 and -9, is seen. Diclofenac and Curcumin inhibited the Bcl-2 protein by directly interacting at the active site by multiple hydrogen bonding, as also evident by negative glide score of Bcl-2. These drugs stimulated apoptosis by increasing reactive oxygen species (ROS) generation and simultaneously decreasing the mitochondrial membrane potential (ΔΨ M). Diclofenac and Curcumin showed anti-neoplastic effects by downregulating PI3-K/Akt/PTEN pathway, inducing apoptosis, increasing ROS generation, and decreasing ΔΨ M. The anti-neoplastic and apoptotic effects were found enhanced when both Diclofenac and Curcumin were administered together, rather than individually.

Cyclooxygenase-2 inhibitor is a robust enhancer of anticancer agents against hepatocellular carcinoma multicellular spheroids

Purpose

Celecoxib, an inhibitor of cyclooxygenase-2 (COX2), was investigated for enhancement of chemotherapeutic efficacy in cancer clinical trials. This study aimed to determine whether celecoxib combined with 5-fluorouracil or sorafenib or gefitinib is beneficial in HepG2 multicellular spheroids (MCSs), as well as elucidate the underlying mechanisms.

Methods

The human hepatocellular carcinoma cell line HepG2 MCSs were used as in vitro models to investigate the effects of celecoxib combined with 5-fluorouracil or sorafenib or gefitinib treatment on cell growth, apoptosis, and signaling pathway.

Results

MCSs showed resistance to drugs compared with monolayer cells. Celecoxib combined with 5-fluorouracil or sorafenib exhibited a synergistic action. Exposure to celecoxib (21.8 μmol/L) plus 5-fluorouracil (8.1 × 10⁻³ g/L) or sorafenib (4.4 μmol/L) increased apoptosis but exerted no effect on COX2, phosphorylated epidermal growth-factor receptor (p-EGFR) and phosphorylated (p)-AKT expression. Gefitinib (5 μmol/L), which exhibits no growth-inhibition activity as a single agent, increased the inhibitory effect of celecoxib. Gefitinib (5 μmol/L) plus celecoxib (21.8 μmol/L) increased apoptosis. COX2, p-EGFR, and p-AKT were inhibited.

Conclusion

Celecoxib combined with 5-fluorouracil or sorafenib or gefitinib may be superior to single-agent therapy in HepG2 MCSs. Our results provided molecular evidence to support celecoxib combination-treatment strategies for patients with human hepatocellular carcinoma. MCSs provided a good model to evaluate the interaction of anticancer drugs.

Finding chemo: the search for marine-based pharmaceutical drugs active against cancer

OBJECTIVES

Cancer affects the health of many people globally. The most common treatment that is used for cancer is chemotherapy, which has shown promising results but not without side effects. Some of these side effects jeopardise further treatment, and this eventually leads to advanced stages of malignancy and mortality. As a result, there is a need for better and safer anticancer compounds such as those found naturally. One of the most abundant natural environments to find such compounds is the sea, and this vast resource has been biomined since the 1950s.

KEY FINDINGS

There are currently three marine anticancer agents marketed (Yondelis, Cytosar-U and Halaven), with several others undergoing clinical trials. This review discusses marine-derived products in clinical use and in clinical trials, and discusses available literature on the growth suppression or pro-apoptotic properties of these compounds, and the molecular mechanisms underpinning these cell biological phenomena.

SUMMARY

The marine environment may hold promising anticancer compounds within its depths, warranting further research to be performed in this area, albeit with respect for the natural ecosystems that are being explored for drug discover and subsequently used for drug development.