Co-treatment with bone marrow-derived mesenchymal stem cells and curcumin improved angiogenesis in myocardium in a rat model of MI

BACKGROUND

The cardioprotective properties of mesenchymal stem cells and the therapeutic potential of curcumin (CUR) have been explored. Combining these approaches may enhance stem cell effectiveness and expedite healing. This study aimed to investigate the synergistic effects of co-treating bone marrow mesenchymal stem cells (BMSCs) with curcumin on vascular endothelial growth factor (VEGF) levels, in a rat model of myocardial ischemia (MI).

METHODS AND RESULTS

Sixty-five male rats were divided into four groups: G1 (healthy control), G2 (MI induced by isoproterenol hydrochloride), G3 (treated with BMSCs), and G4 (co-treated with curcumin and BMSCs). Blood and tissue samples were collected at specific time points (day 1, 7, 15 and 21) after MI induction. Serum levels of lactate dehydrogenase (LDH), creatine kinase (CK), cardiac troponin I (cTnI), aspartate aminotransferase (AST), CK-MB and VEGF were measured. VEGF mRNA and protein expression were evaluated using RT-qPCR and Western blot techniques. Histopathological assessments were performed using H&E staining and CD31 immunofluorescence staining. VEGF expression significantly increased on days 7 and 15 in the CUR-BMSCs group, peaking on day 7. Western blot analysis confirmed elevated VEGF protein expression on days 7 and 15 post-MI. ELISA results demonstrated increased serum VEGF levels on days 7 and 15, reaching the highest level on day 7 in CUR-BMSCs-treated animals. Treated groups showed lower levels of LDH, AST, CK, CK-MB and cTnI compared to the untreated MI group. H&E staining revealed improved myocardial structure, increased formation of new capillaries, in both treatment groups compared to the MI group.

CONCLUSION

Combining curcumin with BMSCs promotes angiogenesis in the infarcted myocardium after 15 days of MI induction. These findings suggest the potential of this combined therapy approach for enhancing cardiac healing and recovery.

Expression and Functionality of Connexin-Based Channels in Human Liver Cancer Cell Lines

Liver cancer cell lines are frequently used in vitro tools to test candidate anti-cancer agents as well as to elucidate mechanisms of liver carcinogenesis. Among such mechanisms is cellular communication mediated by connexin-based gap junctions. The present study investigated changes in connexin expression and gap junction functionality in liver cancer in vitro. For this purpose, seven human liver cancer cell lines, as well as primary human hepatocytes, were subjected to connexin and gap junction analysis at the transcriptional, translational and activity level. Real-time quantitative reverse transcription polymerase chain reaction analysis showed enhanced expression of connexin43 in the majority of liver cancer cell lines at the expense of connexin32 and connexin26. Some of these changes were paralleled at the protein level, as evidenced by immunoblot analysis and in situ immunocytochemistry. Gap junctional intercellular communication, assessed by the scrape loading/dye transfer assay, was generally low in all liver cancer cell lines. Collectively, these results provide a full scenario of modifications in hepatocyte connexin production and gap junction activity in cultured liver cancer cell lines. The findings may be valuable for the selection of neoplastic hepatocytes for future mechanistic investigation and testing of anti-cancer drugs that target connexins and their channels.

Connexin-Based Channel Activity Is Not Specifically Altered by Hepatocarcinogenic Chemicals

Connexin-based channels play key roles in cellular communication and can be affected by deleterious chemicals. In this study, the effects of various genotoxic carcinogenic compounds, non-genotoxic carcinogenic compounds and non-carcinogenic compounds on the expression and functionality of connexin-based channels, both gap junctions and connexin hemichannels, were investigated in human hepatoma HepaRG cell cultures. Expression of connexin26, connexin32, and connexin43 was evaluated by means of real-time reverse transcription quantitative polymerase chain reaction analysis, immunoblot analysis and in situ immunostaining. Gap junction functionality was assessed via a scrape loading/dye transfer assay. Opening of connexin hemichannels was monitored by measuring extracellular release of adenosine triphosphate. It was found that both genotoxic and non-genotoxic carcinogenic compounds negatively affect connexin32 expression. However, no specific effects related to chemical type were observed at gap junction or connexin hemichannel functionality level.

Therapeutic effect of curcumin in gastrointestinal cancers: A comprehensive review

Gastrointestinal (GI) cancers with a high global prevalence are a leading cause of morbidity and mortality. Accordingly, there is a great need to develop efficient therapeutic approaches. Curcumin, a naturally occurring agent, is a promising compound with documented safety and anticancer activities. Recent studies have demonstrated the activity of curcumin in the prevention and treatment of different cancers. According to systematic studies on curcumin use in various diseases, it can be particularly effective in GI cancers because of its high bioavailability in the gastrointestinal tract. Nevertheless, the clinical applications of curcumin are largely limited because of its low solubility and low chemical stability in water. These limitations may be addressed by the use of relevant analogues or novel delivery systems. Herein, we summarize the pharmacological effects of curcumin against GI cancers. Moreover, we highlight the application of curcumin's analogues and novel delivery systems in the treatment of GI cancers.

Curcumin restrains hepatocellular carcinoma progression depending on the regulation of the circ_0078710/miR-378b/PRIM2 axis

PURPOSE

Curcumin has shown anti-tumor activity in multiple malignancies. The aim of our study was to explore the molecular mechanism behind the anti-tumor activity of curcumin in hepatocellular carcinoma (HCC).

METHODS

The proliferation, migration, invasion, and apoptosis were analyzed by 5-ethynyl-2'-deoxyuridine (EDU) assay, transwell migration assay, transwell invasion assay, and flow cytometry. Western blot assay and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were conducted to analyze protein and RNA expression. Dual-luciferase reporter assay, RNA immunoprecipitation (RIP) assay, and RNA-pull down assay were performed to confirm the interaction between microRNA-378b (miR-378b) and circular RNA_0078710 (circ_0078710) or DNA primase, polypeptide 2 (PRIM2). Tumor xenograft assay was conducted to assess the roles of curcumin and circ_0078710 in vivo.

RESULTS

Curcumin stimulation restrained the proliferation, migration, and invasion, and triggered the apoptosis of HCC cells. Curcumin down-regulated the expression of circ_0078710 in HCC cells in a dose-dependent manner. Circ_0078710 knockdown aggravated curcumin-mediated anti-tumor effects in HCC cells. Circ_0078710 acted as a molecular sponge for miR-378b. Circ_0078710 interference-induced effects in curcumin-stimulated HCC cells were partly abolished by the silence of miR-378b. MiR-378b bound to the 3' untranslated region (3'UTR) of PRIM2. PRIM2 overexpression partly reversed circ_0078710 interference-mediated influences in curcumin-treated HCC cells. Circ_0078710 silencing aggravated curcumin-mediated suppressive effect in tumor growth in vivo.

CONCLUSIONS

Circ_0078710 silencing aggravated curcumin-mediated anti-tumor effects through mediating the miR-378b/PRIM2 signaling in HCC cells.

Antisense Tissue Factor Oligodeoxynucleotides Protected Diethyl Nitrosamine/Carbon Tetrachloride-Induced Liver Fibrosis Through Toll Like Receptor4-Tissue Factor-Protease Activated Receptor1 Pathway

Tissue factor (TF) is a blood coagulation factor that has several roles in many non-coagulant pathways involved in different pathological conditions such as angiogenesis, inflammation and fibrogenesis. Coagulation and inflammation are crosslinked with liver fibrosis where protease-activated receptor1 (PAR1) and toll-like receptor4 (TLR4) play a key role. Antisense oligodeoxynucleotides are strong modulators of gene expression. In the present study, antisense TF oligodeoxynucleotides (TFAS) was evaluated in treating liver fibrosis via suppression of TF gene expression. Liver fibrosis was induced in rats by a single administration of N-diethyl nitrosamine (DEN, 200 mg/kg; i. p.) followed by carbon tetrachloride (CCl4, 3 ml/kg; s. c.) once weekly for 6 weeks. Following fibrosis induction, liver TF expression was significantly upregulated along with liver enzymes activities and liver histopathological deterioration. Alpha smooth muscle actin (α-SMA) and transforming growth factor-1beta (TGF-1β) expression, tumor necrosis factor-alpha (TNF-α) and hydroxyproline content and collagen deposition were significantly elevated in the liver. Blocking of TF expression by TFAS injection (2.8 mg/kg; s. c.) once weekly for 6 weeks significantly restored liver enzymes activities and improved histopathological features along with decreasing the elevated α-SMA, TGF-1β, TNF-α, hydroxyproline and collagen. Moreover, TFAS decreased the expression of both PAR1 and TLR4 that were induced by liver fibrosis. In conclusion, we reported that blockage of TF expression by TFAS improved inflammatory and fibrotic changes associated with CCl4+DEN intoxication. In addition, we explored the potential crosslink between the TF, PAR1 and TLR4 in liver fibrogenesis. These findings offer a platform on which recovery from liver fibrosis could be mediated through targeting TF expression.

Curcumin induces apoptotic cell death and protective autophagy by inhibiting AKT/mTOR/p70S6K pathway in human ovarian cancer cells

PURPOSE

Curcumin (Cur), a yellow-colored dietary flavor from the plant (Curcuma longa), has been demonstrated to potentially resist diverse diseases, including ovarian cancer, but drug resistance becomes a major limitation of its success clinically. The key molecule or mechanism associated with curcumin resistance in ovarian cancer still remains unclear. The aim of our study was to investigate the effects of curcumin on autophagy in ovarian cancer cells and elucidate the underlying mechanism.

METHODS

In our study, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), EdU proliferation assay and colony-forming assay were used to assess cell viability. Apoptosis was detected by western blot and flow cytometric analysis of apoptosis. Autophagy was defined by both electron microscopy and immunofluorescence staining markers such as microtubule-associated protein 1 light chain 3 (LC3). Plasmid construction and shRNA transfection helped us to confirm the function of curcumin.

RESULTS

Curcumin reduced cell viability and induced apoptotic cell death by MTT assay in human ovarian cancer cell lines SK-OV-3 and A2780 significantly. Electron microscopy, western blot and immunofluorescence staining proved that curcumin could induce protective autophagy. Moreover, treatment with autophagy-specific inhibitors or stable knockdown of LC3B by shRNA could markedly enhance curcumin-induced apoptosis. Finally, the cells transiently transfected with AKT1 overexpression plasmid demonstrated that autophagy had a direct relationship with the AKT/mTOR/p70S6K pathway.

CONCLUSIONS

Curcumin can induce protective autophagy of human ovarian cancer cells by inhibiting the AKT/mTOR/p70S6K pathway, indicating the synergistic effects of curcumin and autophagy inhibition as a possible strategy to overcome the limits of current therapies in the eradication of epithelial ovarian cancer.

Autophagy in Human Health and Disease: Novel Therapeutic Opportunities

SIGNIFICANCE

In eukaryotes, autophagy represents a highly evolutionary conserved process, through which macromolecules and cytoplasmic material are degraded into lysosomes and recycled for biosynthetic or energetic purposes. Dysfunction of the autophagic process has been associated with the onset and development of many human chronic pathologies, such as cardiovascular, metabolic, and neurodegenerative diseases as well as cancer. Recent Advances: Currently, comprehensive research is being carried out to discover new therapeutic agents that are able to modulate the autophagic process in vivo. Recent evidence has shown that a large number of natural bioactive compounds are involved in the regulation of autophagy by modulating several transcriptional factors and signaling pathways.

CRITICAL ISSUES

Critical issues that deserve particular attention are the inadequate understanding of the complex role of autophagy in disease pathogenesis, the limited availability of therapeutic drugs, and the lack of clinical trials. In this context, the effects that natural bioactive compounds exert on autophagic modulation should be clearly highlighted, since they depend on the type and stage of the pathological conditions of diseases.

FUTURE DIRECTIONS

Research efforts should now focus on understanding the survival-supporting and death-promoting roles of autophagy, how natural compounds interact exactly with the autophagic targets so as to induce or inhibit autophagy and on the evaluation of their pharmacological effects in a more in-depth and mechanistic way. In addition, clinical studies on autophagy-inducing natural products are strongly encouraged, also to highlight some fundamental aspects, such as the dose, the duration, and the possible synergistic action of these compounds with conventional therapy.

Both glypican-3/Wnt/β-catenin signaling pathway and autophagy contributed to the inhibitory effect of curcumin on hepatocellular carcinoma

AIM

The aim of this study is to investigate the role of glypican-3(GPC3)/wnt/β-catenin signaling pathway and autophagy in the regulation of hepatocellular carcinoma (HCC) growth mediated by curcumin.

METHODS

HepG2 cells were treated with various concentrations of curcumin and/or GPC3-targeting siRNA in the presence or absence of 3-MA. Cell proliferation and apoptosis were determined by MTT and TUNEL assay, respectively. Expression of GPC3, β-catenin, c-myc, LC3, and Beclin1 was determined by western blotting. In addition, curcumin was tested in tumor xenografts mice model, Caliper IVIS Lumina II was used to monitor the tumor growth, and GPC3/wnt/β-catenin signaling proteins were determined by western blotting.

RESULTS

Curcumin treatment led to proliferation inhibition and apoptosis induction in HepG2 cells in a concentration-dependent manner, and suppressed HCC tumor growth in vivo. Further analysis showed that curcumin treatment inactivated Wnt/β-catenin signaling and decreased GPC3 expression, silencing of GPC3 expression promoted the effects of curcumin on Wnt/β-catenin signaling. In addition, inhibiting autophagy by 3-MA relieved curcumin-dependent down-regulation of GPC3.

CONCLUSION

Curcumin suppressed HCC tumor growth through down-regulating GPC3/wnt/β-catenin signaling pathway, which was partially mediated by activation of autophagy.

Curcumin differentially affects cell cycle and cell death in acute and chronic myeloid leukemia cells

Curcumin is a phytochemical with potent anti-neoplastic properties. The antitumoral effects of curcumin in cells derived from chronic or acute myeloid leukemia have been already described. However, a comparative study of the cytostatic and cytotoxic effects of curcumin on chronic and acute myeloid leukemia cells has not yet been performed. In the present study, the cellular effects of curcumin on cell lines derived from chronic or acute myeloid leukemia were examined. Dose and time-response assays were performed with curcumin on HL-60 and K562 cells. Cell viability was evaluated with trypan blue exclusion test and cell death by flow cytometry using a fluorescent molecular probe. A cell cycle profile was analyzed, and protein markers of cell cycle progression and cell death were investigated. In the present study, the K562 cells showed a higher sensitivity to the cytostatic and cytotoxic effects of curcumin compared with HL-60. In addition, curcumin induced G1 phase arrest in HL-60 cells and G2/M phase arrest in K562 cells. Furthermore, curcumin-related cell death in HL-60 was associated with the processed forms of caspases-9 and -3 proteins, whereas in K562 cells, both the processed and the unprocessed forms were present. Accordingly, activity of these caspases was significantly higher in HL-60 cells compared with that in K562. In conclusion, curcumin elicits different cellular mechanisms in chronic or acute myeloid leukemia cells and the powerful antitumoral effect was more potent in K562 compared with HL-60 cells.

Curcumin inhibits the growth of liver cancer stem cells through the phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin signaling pathway

Cancer stem cells are considered as a main cause of cancer recurrence. In the present study, the effects of curcumin on the growth of liver cancer stem cells (LCSCs) were investigated. The proliferation and apoptosis of LCSCs were assessed by MTT assays and flow cytometry. Changes in the expression of apoptosis-related proteins were identified by western blotting. The results of the study demonstrated that curcumin treatment inhibited the growth of LCSCs, induced cell apoptosis, as well as regulated the expression of apoptosis-associated proteins and the release of cytochrome c. Further experiments revealed that treatment with curcumin inhibited that the activation of the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) signaling pathway. Treatment with an activator of PI3K/AKT reversed the curcumin-induced growth inhibition of LCSCs. These results demonstrated that curcumin inhibited the growth of LCSCs through the PI3K/AKT/mTOR signaling pathway. Thus, the present study suggested that curcumin may be a potentially efficient agent in the treatment of liver cancer.