Butyrate-induced proapoptotic and antiangiogenic pathways in EAT cells require activation of CAD and downregulation of VEGF

Sodium butyrate-loaded nanoparticles coated with chitosan for the treatment of neovascularization in age-related macular degeneration: ocular biocompatibility and antiangiogenic activity

Sodium butyrate-loaded nanoparticles coated chitosan (NaBu-loaded nanoparticles/CS) were developed to treat the choroidal neovascularization in wet age-related macular degeneration (AMD). The nanoparticles were produced by double emulsification and solvent evaporation technique, optimized by experimental statistical design, characterized by analytical methods, investigated in terms of in vitro and in vivo ocular biocompatibility, and evaluated as an antiangiogenic system in vivo. The NaBu-loaded nanoparticles/CS were 311.1 ± 3.1 nm in diameter with a 0.208 ± 0.007 polydispersity index; had a +56.3 ± 2.6 mV zeta potential; showed a 92.3% NaBu encapsulation efficiency; and sustained the drug release over 35 days. The NaBu-loaded nanoparticles/CS showed no toxicity to human retinal pigment epithelium cells (ARPE-19 cells); was not irritant to the chorioallantoic membrane (CAM); did not interfere in the integrity of the retinal layers of rat's eyes, as detected by the Optical Coherence Tomography and histopathology; and inhibited the angiogenesis in CAM assay. The NaBu-loaded nanoparticles/CS could be a therapeutic alternative to limit the neovascularization in AMD.

GPR43 regulates sodium butyrate-induced angiogenesis and matrix remodeling

Butyrate is a short-chain fatty acid (SCFA) derived from microbiota and is involved in a range of cell processes in a concentration-dependent manner. Low concentrations of sodium butyrate (NaBu) were shown to be proangiogenic. However, the mechanisms associated with these effects are not yet fully known. Here, we investigated the contribution of the SCFA receptor GPR43 in the proangiogenic effects of local treatment with NaBu and its effects on matrix remodeling using the sponge-induced fibrovascular tissue model in mice lacking the Gpr43 gene (Gpr43-KO) and the wild-type (WT) mice. We demonstrated that NaBu (0.2 mM intraimplant) treatment enhanced the neovascularization process, blood flow, and VEGF levels in a GPR43-dependent manner in the implants. Moreover, NaBu was able to modulate matrix remodeling aspects of the granulation tissue such as proteoglycan production, collagen deposition, and α-smooth muscle actin (α-SMA) expression in vivo, besides increasing transforming growth factor (TGF)-β1 levels in the fibrovascular tissue, in a GPR43-dependent manner. Interestingly, NaBu directly stimulated L929 murine fibroblast migration and TGF-β1 and collagen production in vitro. GPR43 was found to be expressed in human dermal fibroblasts, myofibroblasts, and endothelial cells. Overall, our findings evidence that the metabolite-sensing receptor GPR43 contributes to the effects of low dose of NaBu in inducing angiogenesis and matrix remodeling during granulation tissue formation. These data provide important insights for the proposition of new therapeutic approaches based on NaBu, beyond the highly explored intestinal, anti-inflammatory, and anticancer purposes, as a local treatment to improve tissue repair, particularly, by modulating granulation tissue components.NEW & NOTEWORTHY Our data show the contribution of the metabolite-sensing receptor GPR43 in the effects of low dose of sodium butyrate (NaBu) on stimulating angiogenesis and extracellular matrix remodeling in a model of granulation tissue formation in mice. We also show that human dermal fibroblasts, myofibroblasts, and endothelial cells express the receptor GPR43. These data provide important insights for the use of NaBu in local therapeutic approaches applicable to tissue repair in sites other than the intestine.

Novel 3-(3, 5-difluoro-4-hydroxyphenyl)-1-(naphthalen-2-yl) prop-2-en-1-one as a potent inhibitor of MAP-kinase in HeLa cell lines and anti-angiogenic activity is mediated by HIF-1α in EAC animal model

In the present investigation, we synthesized chalcone bearing naphthalene compound d1, and on the basis of ¹H-NMR, ¹³C NMR, and LC-MS data we had specified the structure of the synthesized compound. The resultant compound d1 was assessed for their antiproliferative action against human cancer cell lines (HeLa, HCT116, HT29, MDA-MB-231, MCF-7, and SKBR3). The IC₅₀ range was estimated at 5.58 to 11.13 μM shows that compound d1 had remarkable anticancer activity on HeLa cell lines. Besides, it was discovered that d1 incited the mitochondrial apoptotic pathway by controlling Bax and Bcl-2 transcripts by expanding the Caspase 3 activation. We depicted the in-vivo effects of tumor advancement and the antiangiogenic activity of d1 in the EAC animal model. Tumor growth had inhibited and without symptoms the longevity of EAC containing mice expanded by the treatment of d1. Inhibition of nuclear transcriptional factor HIF-1α in EAC cells and finally it also inhibited phosphorylation of downstream signaling proteins such as ERK_1/2, p38, and JNK in HeLa cells. The present investigation uncovered that d1 indicated noteworthy tumor-repressing abilities much less concentration in in-vitro and in-vivo recommended that compound d1 as the potent anticancer medication.

The tumor antagonistic steroidal alkaloid Solanidine prompts the intrinsic suicidal signal mediated DFF-40 nuclear import and nucleosomal disruption

Aim Deformity in the cellular homeostatic event associated with cell survival and apoptosis are committing factors for carcinogenesis. Interventions of these events by pharmacologically active agent gain predominance in cancer treatment. In current investigation Solanidine, a steroidal alkaloid was evaluated on tumorigenesis by targeting death signal using multiple tumor cells and model systems.

MAIN METHODS

Anti-proliferative effect was evaluated using cytotoxic studies. Prolonged cytotoxic effect of Solanidine was examined by colony formation assay. Exhibition of apoptotic hallmark induced by Solanidine was examined using FACS analysis, Annexin-V staining, Acridine orange staining, TUNEL assay. Altered gene expression was evaluated using Immunoblot, Immunofluorescence and Immunohistochemistry technique. In-vitro results were revalidated in EAC solid tumor and CAM xenograft model.

KEY FINDINGS

Solanidine exerts its potential effect in a target specific manner. The cytotoxic/anticlonogenic activity was due to induction of typical cellular apoptotic hallmarks and cell cycle blockage at S-G2/M phase. The molecular events underlying this effect is through activation of intrinsic pathway via Bax, Bad and Cytochrome c activation by neutralizing Bcl-2 expression, along with downregulated PI3K/Akt survival signal. As a consequence, downstream pro apoptogenic gene, active Caspase-3 was over expressed by Solanidine to cleave its substrate PARP and promotes nuclear import of DFF-40. Anti-carcinogenic aptitude was further confirmed by murine solid tumors and in-vivo CAM xenograft studies.

SIGNIFICANCE

Solanidine emerged as active molecule against tomorigenesis by activating nuclear import of DFF-40 mediated nucleosomal disruption and cell demise. It can be developed as a potential apoptogenic small molecule for cancer therapy.

Immunomodulatory glc/man-directed Dolichos lablab lectin (DLL) evokes anti-tumour response in vivo by counteracting angiogenic gene expressions

Neovascularization and jeopardized immunity has been critically emphasized for the establishment of malignant progression. Lectins are the diverse class of carbohydrate interacting proteins, having great potential as immunopotentiating and anti-cancer agents. The present investigation sought to demonstrate the anti-proliferative activity of Dolichos lablab lectin (DLL) encompassing immunomodulatory attributes. DLL specific to glucose and mannose carbohydrate moieties has been purified to homogeneity from the common dietary legume D. lablab. Results elucidated that DLL agglutinated blood cells non-specifically and displayed striking mitogenicity to human and murine lymphocytes in vitro with interleukin (IL)-2 production. The DLL-conditioned medium exerted cytotoxicity towards malignant cells and neoangiogenesis in vitro. Similarly, in-vivo anti-tumour investigation of DLL elucidated the regressed proliferation of ascitic and solid tumour cells, which was paralleled with blockade of tumour neovasculature. DLL-treated mice showed an up-regulated immunoregulatory cytokine IL-2 in contrast to severely declined levels in control mice. Mechanistic validation revealed that DLL has abrogated the microvessel formation by weakening the proangiogenic signals, specifically nuclear factor kappa B (NF-κB), hypoxia inducible factor 1α (HIF-1 α), matrix metalloproteinase (MMP)-2 and 9 and vascular endothelial growth factor (VEGF) in malignant cells leading to tumour regression. In summary, it is evident that the dietary lectin DLL potentially dampens the malignant establishment by mitigating neoangiogenesis and immune shutdown. For the first time, to our knowledge, this study illustrates the critical role of DLL as an immunostimulatory and anti-angiogenic molecule in cancer therapeutics.

Low Concentration of Sodium Butyrate from Ultrabraid+NaBu suture, Promotes Angiogenesis and Tissue Remodelling in Tendon-bones Injury

Sodium butyrate (NaBu), a form of short-chain fatty acid (SCFA), acts classically as a potent anti-angiogenic agent in tumour angiogenesis models, some authors demonstrated that low concentrations of NaBu may contribute to healing of tendon-bone injury in part at least through promotion of tissue remodelling. Here, we investigated the effects of low-range concentrations of NaBu using in vitro and in vivo assays using angiogenesis as the primary outcome measure and the mechanisms through which it acts. We demonstrated that NaBu, alone or perfused from the UltraBraid+NaBu suture was pro-angiogenic at very low-range doses promoting migration, tube formation and cell invasion in bovine aortic endothelial cells (BAECs). Furthermore, cell exposure to low NaBu concentrations increased expression of proteins involved in angiogenic cell signalling, including p-PKCβ1, p-FAK, p-ERK1/2, p-NFκβ, p-PLCγ1 and p-VEGFR2. In addition, inhibitors of both VEGFR2 and PKCβ1 blocked the angiogenic response. In in vivo assays, low concentrations of NaBu induced neovascularization in sponge implants in mice, evidenced by increased numbers of vessels and haemoglobin content in these implants. The findings in this study indicate that low concentrations of NaBu could be an important compound to stimulate angiogenesis at a site where vasculature is deficient and healing is compromised.

Synthesis and tumor inhibitory activity of novel coumarin analogs targeting angiogenesis and apoptosis

A sequence of coumarin analogs 5a-j was obtained by multi step synthesis from hydroxy benzophenones (1a-j). The in vitro antiproliferative effect of the title compounds was tested against Ehrlich ascites carcinoma (EAC) and Daltons lymphoma ascites (DLA) cell lines. Among the series, compound 5c with bromo group in the benzophenone moiety was endowed with excellent antiproliferative potency with significant IC50 value. Further, in vivo antitumor effect of compound 5c against murine EAC and solid DL tumor model system was evident by the extended survivality. The tumor inhibitory mechanism of compound 5c was due to the antiangiogenesis and promotion of apoptosis. These results suggest possible applications of compound 5c which could be developed as a potent anticancer drug in the near future.

Sodium butyrate enhances the cytotoxic effect of cisplatin by abrogating the cisplatin imposed cell cycle arrest

Background

Histone deacetylase inhibitors have been proposed as potential enhancers of the cytotoxic effect of cisplatin and other anticancer drugs. Their application would permit the use of lower therapeutic doses and reduction of the adverse side effects of the drugs. However, the molecular mechanisms by which they sensitize the cells towards anticancer drugs are not known in details, which is an obstacle in developing effective therapeutic protocols.

Results

In the present work, we studied the molecular mechanisms by which sodium butyrate sensitizes cancer cells towards cisplatin. HeLa cells were treated with 5 mM butyrate, with 8 μM cis-diaminedichloroplatinum II (cisplatin), or with both. Cells treated with both agents showed approximately two-fold increase of the mortality rate in comparison with cells treated with cisplatin only. Accordingly, the life span of albino mice transfected with Ehrlich ascites tumor was prolonged almost two-fold by treatment with cisplatin and butyrate in comparison with cisplatin alone. This showed that the observed synergism of cisplatin and butyrate was not limited to specific cell lines or in vitro protocols, but was also expressed in vivo during the process of tumor development. DNA labeling and fluorescence activated cell sorting experiments showed that cisplatin treatment inhibited DNA synthesis and arrested HeLa cells at the G1/S transition and early S phase of the cell cycle. Western blotting and chromatin immunoprecipitation revealed that this effect was accompanied with a decrease of histone H4 acetylation levels. Butyrate treatment initially reversed the effect of cisplatin by increasing the levels of histone H4 acetylation in euchromatin regions responsible for the G1/S phase transition and initiation of DNA synthesis. This abrogated the cisplatin imposed cell cycle arrest and the cells traversed S phase with damaged DNA. However, this effect was transient and continued only a few hours. The long-term effect of butyrate was a massive histone acetylation in both eu- and heterochromatin, inhibition of DNA replication and apoptosis.

Conclusion

The study presents evidence that cell sensitization towards cisplatin by sodium butyrate is due to hyperacetylation of histone H4 in specific chromatin regions, which temporarily abrogates the cisplatin imposed cell cycle arrest.

Butyrate-induced phosphatase regulates VEGF and angiogenesis via Sp1

Sp1 is a ubiquitous transcription factor and master regulator of various eukaryotic gene expression. Better understanding of the role of increased Sp1 levels on angiogenic regulation and the regulatory regions of that transcription factor may act as a useful target in 'transcriptional therapy'. At the molecular level, butyrate inhibits Sp1-DNA binding activity by promoting Sp1 protein dephosphorylation in EAT cells. It also inhibits Sp1 binding activity and reduces expression of VEGF gene, thereby inhibiting angiogenesis. It was confirmed that butyrate induces expression of a tyrosine phosphatase by RT-PCR, cDNA sequence analysis, protein ESI-MS analysis and protein sequence homology comparison. Thus our result strongly suggests that inhibition of angiogenesis by butyrate involves Sp1 dephosphorylation and down-regulation of VEGF gene expression. Further, butyrate inhibits neoangiogenesis induced by tumor cells and VEGF in peritoneum of EAT bearing mice and rat cornea.

Induction of caspase-3 activated DNase mediated apoptosis by hexane fraction of Tinospora cordifolia in EAT cells

Tinospora cordifolia (Guduchi) has been used for centuries for treating various ailments including cancer in Ayurvedic system of medicine. In this study, we report the mechanism of cell death exhibited by the hexane extract fraction of T. cordifolia (TcHf) against Ehrlich ascites tumor (EAT) in mice. Treatment of EAT bearing animals with TcHf resulted in growth inhibition and induction of apoptosis in a dose-dependent manner. TcHf induced the formation of apoptotic bodies, nuclear condensation, typical DNA ladder, activation of caspase-3, decreased cell number and ascites volume. We examined TcHf for its effect on proliferation and cell cycle progression in EAT cells. The results showed that TcHf inhibited the proliferation of EAT cells by blocking cell cycle progression in the G1 phase. In Western blot analysis, apoptosis in the EAT cells was associated with the constitutive expression of caspase activated DNase (CAD) in both nucleus and cytoplasm after TcHf treatment. Further more the expression of pro-apoptotic gene, Bax, was increased and the expression of anti-apoptotic gene, Bcl-2, was decreased in a time dependent manner by TcHf treatment. All results indicate that the hexane fraction of T. cordifolia is capable of inducing apoptosis in EAT cells in vivo.

Purification and characterization of butyrate-induced protein phosphatase involved in apoptosis of Ehrlich ascites tumor cells

Short chain fatty acids including butyrate exhibit wide variety of biological effects towards cell growth, morphology and gene expression. In this report, we study the mechanism by which butyrate (BuA) modulates the expression of protein phosphatase when treated to the cells. As a model system, we used Ehrlich Ascites Tumor (EAT) cells in which BuA-treatment induces expression of a protein phosphatase enzyme. Subsequently, BuA-induced protein phosphatase has been biochemically purified and characterized. Further, pretreatment of caspase-3 inhibitor abolished the activity of BuA-induced protein phosphatase indicating the involvement of caspase-3 in the activation of BuA-induced protein phosphatase. In addition, the relationship between BuA-induced protein phosphatase and apoptosis has been verified. Activation of endonuclease-II has been shown in BuA-treated EAT cells and that activity was completely inhibited by sodium orthovanadate, a tyrosine phosphatase inhibitor suggesting that endonuclease-II may serve as a possible down-stream target for BuA-induced protein phosphatase. Together, the data suggest that activation of protein phosphatase may be an early and essential step in BuA-mediated apoptotic signaling pathway in EAT cells.