Abstract Arachidonic acid (AA) pathway, a metabolic process, plays a key role in carcinogenesis. Hence, AA pathway metabolic enzymes phospholipase A2 s (PLA2 s), cyclooxygenases (COXs) and ...lipoxygenases (LOXs) and their metabolic products, such as prostaglandins and leukotrienes, have been considered novel preventive and therapeutic targets in cancer. Bioactive natural products are a good source for development of novel cancer preventive and therapeutic drugs, which have been widely used in clinical practice due to their safety profiles. AA pathway inhibitory natural products have been developed as chemopreventive and therapeutic agents against several cancers. Curcumin, resveratrol, apigenin, anthocyans, berberine, ellagic acid, eugenol, fisetin, ursolic acid, 6-gingerol, guggulsteone, lycopene and genistein are well known cancer chemopreventive agents which act by targeting multiple pathways, including COX-2. Nordihydroguaiaretic acid and baicalein can be chemopreventive molecules against various cancers by inhibiting LOXs. Several PLA2 s inhibitory natural products have been identified with chemopreventive and therapeutic potentials against various cancers. In this review, we critically discuss the possible utility of natural products as preventive and therapeutic agents against various oncologic diseases, including prostate, pancreatic, lung, skin, gastric, oral, blood, head and neck, colorectal, liver, cervical and breast cancers, by targeting AA pathway. Further, the current status of clinical studies evaluating AA pathway inhibitory natural products in cancer is reviewed. In addition, various emerging issues, including bioavailability, toxicity and explorability of combination therapy, for the development of AA pathway inhibitory natural products as chemopreventive and therapeutic agents against human malignancy are also discussed.
We have previously shown that celecoxib in combination with an antibiotic, increase the bacterial sensitivity to antibiotics. However, the underlying molecular mechanism remained elusive. Efficacy of ...the combinatorial treatment of celecoxib and ampicillin in vitro was evaluated on macrophage-phagocytosed S. aureus. To elucidate the mechanism, signaling pathway of infection and inflammation involving TLR2, JNK, SIRT1 and NF-κB was studied by FACS, Western blot, ELISA and activity assays. Combinatorial treatment of ampicillin and celecoxib reduced the bacterial load in the macrophages. Further studies clearly suggested the activation of the master regulator of oxidative stress and inflammation SIRT1, by celecoxib when used alone and/or in combination with ampicillin. Also, the results indicated that celecoxib inhibited JNK phosphorylation thereby stabilizing and activating SIRT1 protein that inhibited the COX-2 gene transcription with a significant decrease in the levels of protein inflammatory cytokines like IL-6, MIP-1α and IL-1β via inhibition of NF-κB. SIRT1 activation by celecoxib also resulted in increase of catalase and peroxidase activity with a decrease in Nitric oxide levels. In conclusion, we demonstrate a novel role of celecoxib in controlling inflammation as an enhancer of antibiotic activity against bacteria by modulating SIRT1.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Histone deacetylases (HDACs) are involved in epigenetic gene regulation via deacetylation of acetylated lysine residues of both histone and non-histone proteins. Among the 18 HDACs identified in ...humans, HDAC8, a class I HDAC, is best understood structurally and enzymatically. However, its precise subcellular location, function in normal cellular physiology, its protein partners and substrates still remain elusive.
The subcellular localization of HDAC8 was studied using immunofluorescence and confocal imaging. The binding parterns were identified employing immunoprecipitation (IP) followed by MALDI-TOF analysis and confirmed using in-silico protein-protein interaction studies, HPLC-based in vitro deacetylation assay, intrinsic fluorescence spectrophotometric analysis, Circular dichroism (CD) and Surface Plasmon Resonance (SPR). Functional characterization of the binding was carried out using immunoblot and knockdown by siRNA. Using one way ANOVA statistical significance (n = 3) was determined.
Here, we show that HDAC8 and its phosphorylated form (pHDAC8) localized predominantly in the cytoplasm in cancerous, HeLa, and non-cancerous (normal), HEK293T, cells, although nucleolar localization was observed in HeLa cells. The study identified Alpha tubulin as a novel interacting partner of HDAC8. Further, the results indicated binding and deacetylation of tubulin at ac-lys40 by HDAC8. Knockdown of HDAC8 by siRNA, inhibition of HDAC8 and/or HDAC6 by PCI-34051 and tubastatin respectively, cell-migration, cell morphology and cell cycle analysis clearly explained HDAC8 as tubulin deacetylase in HeLa cells and HDAC6 in HEK 293 T cells.
HDAC8 shows functional redundancy with HDAC6 when overexpressed in cervical cancer cells, HeLa, and deacetylaes ac-lys40 of alpha tubulin leading to cervical cancer proliferation and progression.
In the present study, the in vitro anticancer (antiproliferative) effects of Bacillus coagulans Unique IS2 were evaluated on human colon cancer (COLO 205), cervical cancer (HeLa), and chronic myeloid ...leukemia (K562) cell lines with a human embryonic kidney cell line (HEK 293T) as noncancerous control cells. The Cytotoxicity assay (MTT) clearly demonstrated a 22%, 31.7%, and 19.5% decrease in cell proliferation of COLO 205, HeLa, and K562 cells, respectively, when compared to the noncancerous HEK 293T cells. Normal phase-contrast microscopic images clearly suggested that the mechanism of cell death is by apoptosis. To further confirm the induction of apoptosis by Unique IS2, the sub-G0-G1 peak of the cell cycle was quantified using a flow cytometer and the data indicated 40% of the apoptotic cells in Unique IS2-treated COLO cells when compared with their untreated control cells. The Western blot analysis showed an increase in pro-apoptotic protein BAX, decrease in antiapoptotic protein, Bcl2, decrease in mitochondrial membrane potential, increase in cytochrome c release, increase in Caspase 3 activity, and cleavage of poly(ADP-ribose) polymerase. The present study suggests that the heat-killed culture supernatant of B. coagulans can be more effective in inducing apoptosis of colon cancer cells and that can be considered for adjuvant therapy in the treatment of colon carcinoma.
Celotno besedilo
Dostopno za:
DOBA, IJS, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK, VSZLJ
Cervical cancer, a leading global cause of female mortality, exhibits diverse molecular aberrations influencing gene expression and signaling pathways. Epigenetic factors, including histone ...deacetylases (HDACs) such as HDAC8 and HDAC6, along with microRNAs (miRNAs), play pivotal roles in cervical cancer progression. Recent investigations have unveiled miRNAs as potential regulators of HDACs, offering a promising therapeutic avenue. This study employed in-silico miRNA prediction, qRT-PCR co-expression studies, and Dual-Luciferase reporter assays to identify miRNAs governing HDAC8 and HDAC6 in HeLa, cervical cancer cells. Results pinpointed miR-497–3p and miR-324–3p as novel negative regulators of HDAC8 and HDAC6, respectively. Functional assays demonstrated that miR-497–3p overexpression in HeLa cells suppressed HDAC8, leading to increased acetylation of downstream targets p53 and α-tubulin. Similarly, miR-324–3p overexpression inhibited HDAC6 mRNA and protein expression, enhancing acetylation of Hsp90 and α-tubulin. Notably, inhibiting HDAC8 via miRNA overexpression correlated with reduced cell viability, diminished epithelial-to-mesenchymal transition (EMT), and increased microtubule bundle formation in HeLa cells. In conclusion, miR-497–3p and miR-324–3p emerge as novel negative regulators of HDAC8 and HDAC6, respectively, with potential therapeutic implications. Elevated expression of these miRNAs in cervical cancer cells holds promise for inhibiting metastasis, offering a targeted approach for intervention in cervical malignancy.
•MiR-497–3p negatively regulates HDAC8 mRNA.•MiR-497–3p is a tumor suppressor miRNA and inhibits EMT of HeLA cells.•MiR-324–3p negatively regulates HDAC6 mRNA.•MiR-324–3p is downregulated in leukemic K562 cells.
A focused library of novel bis-heterocycles encompassing 2-mercapto benzothiazole and 1,2,3-triazoles were synthesized using click chemistry approach. The synthesized compounds have been tested for ...their anti-inflammatory activity by using biochemical cyclooxygenase (COX) activity assays and carrageenan-induced hind paw edema. Among the tested compounds, compound 4d demonstrated a potent selective COX-2 inhibition with COX-2/COX-1 ratio of 0.44. Results from carrageenan-induced hind paw edema showed that compounds 4a, 4d, 4e and 4f posses significant anti-inflammatory activity as compared to the standard drug Ibuprofen. The compounds showing significant activity were further subjected to anti-nociceptive activity by writhing test. These four compounds have shown comparable activity with the standard Ibuprofen. Further ulcerogenic studies shows that none of these compounds causing gastric ulceration.
Novel bis-heterocycles encompassing 2-mercapto benzothiazole and 1,2,3-triazoles demonstrated a potent selective COX-2 inhibition and significant anti-inflammatory activity as compared to the standard drug Ibuprofen without causing any ulceration. Display omitted
► New bis-heterocycles bearing 2-mercapto benzothiazole and triazoles were synthesized. ► Some of the compounds demonstrated a potent selective COX-2 inhibition. ► Molecular docking study also confirms strong binding potential towards COX-2. ► Significant anti-inflammatory activity in vivo was observed as compared to Ibuprofen. ► Compounds 4d and 4e are showing better analgesic activity compared to Ibuprofen.
Neuroblastoma is the most common extracranial solid tumor found in children and survival rate is extremely meager. HDAC8, a class I zinc-dependent enzyme, is a potential drug target for treatment of ...neuroblastoma and T cell lymphoma. Most of the HDAC8 inhibitors discovered till date contains a hydroxamic acid group which acts as a zinc binding group. The high binding affinity to the zinc and other ions results in adverse effects. Also, the non-selective inhibition of HDACs cause a variety of side effects. The objective of this is to identify structurally diverse, non-hydroxamate, novel, potential and selective HDAC8 inhibitors. A number of five featured pharmacophore hypotheses were generated using 32 known selective HDAC8 inhibitors. The hypotheses ADDRR.4 were selected for building 3D QSAR model. This model has an excellent correlation coefficient and good predictive ability, which was employed for virtual screening of Phase database containing 4.3 × 10
molecules. The resultant hits with fitness score >1.0 were optimized using in-silico ADMET (absorption, distribution, metabolism, excretion, and toxicity) and XP glide docking studies. On the basis of pharmacophore matching, interacting amino acid residues, XP glide score, more affinity towards HDAC8 and less affinity towards other HDACs, and ADME results five hits- SD-01, SD-02, SD-03, SD-04 and SD-05 with new structural scaffolds, non-hydroxamate were selected for in vitro activity study. SD-01 and SD-02 were found to be active in the nanomolar (nM) range. SD-01 had considerably good selectivity for HDAC8 over HDAC6 and SD-02 had marginal selectivity for HDAC6 over HDAC8. The compounds SD-01 and SD-02 were found to inhibit HDAC8 at concentrations (IC
) 9.0 nM and 2.7 nM, respectively.
► Novel small molecule SIRT1 inhibitor better than sirtinol. ► IC
50 500
nM. ► Specific tumor cytotoxicity towards breast cancer cells. ► Restoration of H3K9 acetylation levels to baseline when ...co-treated with SIRT1 activator (Activator X) and inhibitor (ILS-JGB-1741).
Overexpression of SIRT1, a NAD
+-dependent class III histone deacetylases (HDACs), is implicated in many cancers and therefore could become a promising antitumor target. Here we demonstrate a small molecule SIRT1 inhibitor, ILS-JGB-1741(JGB1741) with potent inhibitory effects on the proliferation of human metastatic breast cancer cells, MDA-MB 231. The molecule has been designed using medicinal chemistry approach based on known SIRT1 inhibitor, sirtinol. The molecule showed a significant inhibition of SIRT1 activity compared to sirtinol. Studies on the antitumor effects of JGB on three different cancer cell lines, K562, HepG2 and MDA-MB 231 showed an IC
50 of 1, 10 and 0.5
μM, respectively. Further studies on MDA-MB 231 cells showed a dose-dependent increase in K9 and K382 acetylation of H3 and p53, respectively. Results also demonstrated that JGB1741-induced apoptosis is associated with increase in cytochrome
c release, modulation in Bax/Bcl2 ratio and cleavage of PARP. Flowcytometric analysis showed increased percentage of apoptotic cells, decrease in mitochondrial membrane potential and increase in multicaspase activation. In conclusion, the present study indicates the potent apoptotic effects of JGB1741 in MDA-MB 231 cells.
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•Synthesis of 2,5-disubstituted 1,3,4-oxadiazoles–glycine/alanine hybrids (10a–10j).•In silico and in vitro evaluation of (10a–10j) as class I HDAC inhibitors.•All compounds showed ...cytotoxic effects on breast cancer cell line, MDA-MB-231.•Compound 10b showed high binding affinity and moderate selectivity to HDAC8.•Compound 10b showed potent anti-proliferative effects on MDA-MB-231 cells.
Oxadiazole is a heterocyclic compound containing an oxygen atom and two nitrogen atoms in a five-membered ring. Of the four oxadiazoles known, 1,3,4-oxadiazole has become an important structural motif for the development of new drugs and the compounds containing 1,3,4-oxadiazole cores have a broad spectrum of biological activity. Herein, we describe the design, synthesis and biological evaluation of a series of novel 2,5-disubstituted 1,3,4-oxadiazoles (10a–10j) as class I histone deacetylase (HDAC) inhibitors. The compounds were designed and evaluated for HDAC8 selectivity using in silico docking software (Glide) and the top 10 compounds with high dock score and obeying Lipinski’s rule were synthesized organically. Further the biological HDAC inhibitory and selectivity assays and anti-proliferative assays were carried out. In in silico and in vitro studies, all compounds (10a–10j) showed significant HDAC inhibition and exhibited HDAC8 selectivity. Among all tested compounds, 10b showed substantial HDAC8 inhibitory activity and better anticancer activity which is comparable to the positive control, a FDA approved drug, vorinostat (SAHA). Structural activity relation is discussed with various substitutions in the benzene ring connected on 1,3,4-oxadizole and glycine/alanine. The study warranted further investigations to develop HDAC8-selective inhibitory molecule as a drug for neoplastic diseases. Novel 1,3,4-oxadizole substituted with glycine/alanine showed HDAC8 inhibition.
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