Multifunctional Curcumin Mediate Multitherapeutic Effects

Curcumin Combination Chemotherapy: The Implication and Efficacy in Cancer

Many chemotherapeutic drugs have been used for the treatment of cancer, for instance, doxorubicin, irinotecan, 5-fluorouracil, cisplatin, and paclitaxel. However, the effectiveness of chemotherapy is limited in cancer therapy due to drug resistance, therapeutic selectivity, and undesirable side effects. The combination of therapies with natural compounds is likely to increase the effectiveness of drug treatment as well as reduce the adverse outcomes. Curcumin, a polyphenolic isolated from Curcuma longa, belongs to the rhizome of Zingiberaceae plants. Studies from in vitro and in vivo revealed that curcumin exerts many pharmacological activities with less toxic effects. The biological mechanisms underlying the anticancer activity of co-treatment curcumin and chemotherapy are complex and worth to discuss further. Therefore, this review aimed to address the molecular mechanisms of combined curcumin and chemotherapy in the treatment of cancer. The anticancer activity of combined nanoformulation of curcumin and chemotherapy was also discussed in this study. Taken together, a better understanding of the implication and underlying mechanisms of action of combined curcumin and chemotherapy may provide a useful approach to combat cancer diseases.

In Silico Prediction of PAMPA Effective Permeability Using a Two-QSAR Approach

Oral administration is the preferred and predominant route of choice for medication. As such, drug absorption is one of critical drug metabolism and pharmacokinetics (DM/PK) parameters that should be taken into consideration in the process of drug discovery and development. The cell-free in vitro parallel artificial membrane permeability assay (PAMPA) has been adopted as the primary screening to assess the passive diffusion of compounds in the practical applications. A classical quantitative structure–activity relationship (QSAR) model and a machine learning (ML)-based QSAR model were derived using the partial least square (PLS) scheme and hierarchical support vector regression (HSVR) scheme to elucidate the underlying passive diffusion mechanism and to predict the PAMPA effective permeability, respectively, in this study. It was observed that HSVR executed better than PLS as manifested by the predictions of the samples in the training set, test set, and outlier set as well as various statistical assessments. When applied to the mock test, which was designated to mimic real challenges, HSVR also showed better predictive performance. PLS, conversely, cannot cover some mechanistically interpretable relationships between descriptors and permeability. Accordingly, the synergy of predictive HSVR and interpretable PLS models can be greatly useful in facilitating drug discovery and development by predicting passive diffusion.

Curcumin suppresses epithelial-to-mesenchymal transition of peritoneal mesothelial cells (HMrSV5) through regulation of transforming growth factor-activated kinase 1 (TAK1)

Objective

Peritoneal fibrosis remains a serious complication of long-term peritoneal dialysis (PD) leading to peritoneal membrane ultrafiltration failure. Epithelial–mesenchymal transition (EMT) of peritoneal mesothelial cells (PMCs) is a key process of peritoneal fibrosis. Curcumin has been previously shown to inhibit EMT of renal tubular epithelial cells and prevent renal fibrosis. There are only limited reports on inhibition of PMCs-EMT by curcumin. This study aimed to investigate the effect of curcumin on the regulation of EMT and related pathway in PMCs treated with glucose-based PD.

Methods

EMT of human peritoneal mesothelial cells (HMrSV5) was induced with glucose-based peritoneal dialysis solutions (PDS). Cells were divided into a control group, PDS group, and PDS group receiving varied concentrations of curcumin. Cell Counting Kit-8 (CCK-8) assay was used to measure cell viability, and a transwell migration assay was used to verify the capacity of curcumin to inhibit EMT in HMrSV5 cells. Real-time quantitative PCR and western blot were used to detect the expression of genes and proteins associated with the EMT.

Results

High glucose PDS decreased cell viability and increased migratory capacity. Curcumin reversed growth inhibition and migration capability of human peritoneal mesothelial cells (HPMCs). In HMrSV5 cells, high glucose PDS also decreased expression of epithelial markers, and increased expression of mesenchymal markers, a characteristic of EMT. Real-time RT-PCR and western blot revealed that, compared to the 4.25% Dianeal treated cells, curcumin treatment resulted in increased expression of E-cadherin (epithelial marker), and decreased expression of α-SMA (mesenchymal markers) (P < 0.05). Furthermore, curcumin reduced mRNA expression of two extracellular matrix protein, collagen I and fibronectin. Curcumin also reduced TGF-β1 mRNA and supernatant TGF-β1 protein content in the PDS-treated HMrSV5 cells (P < 0.05). Furthermore, it significantly reduced protein expression of p-TAK1, p-JNK and p-p38 in PDS-treated HMrSV5 cells.

Conclusions

Our results demonstrate that curcumin showed an obvious protective effect on PDS-induced EMT of HMrSV5 cells and suggest implication of the TAK1, p38 and JNK pathway in mediating the effects of curcumin in EMT of MCs.

A randomized, double-blind, placebo-controlled trial to evaluate the role of curcumin in prostate cancer patients with intermittent androgen deprivation

BACKGROUND

The anti-cancer activities of curcumin are well-documented from preclinical studies using prostate cancer models. Our objective was to evaluate the anti-cancer activity of oral curcumin in patients with prostate cancer.

METHODS

This randomized, double-blind, placebo-controlled trial was performed on patients with prostate cancer who received intermittent androgen deprivation (IAD). Participants who finished the first on-treatment period of IAD were randomized into a curcumin or placebo group. The patients took oral curcumin (1440 mg/day) or placebo for six months and were followed up until the beginning of the second on-treatment. The primary end-point was duration of the first off-treatment. The secondary end-points were change in PSA and testosterone levels during 6 months, PSA progression rate, and health-related quality of life (HRQOL) scores at 6 months. Safety assessments included adverse event, adverse drug reaction, and serious adverse event.

RESULTS

A total of 97 participants were randomized 1:1 to curcumin (n = 49) and placebo (n = 48) groups. Among them, 82 patients (84.5%) were evaluable for the analysis (39 and 43 patients in the curcumin and placebo groups, respectively). The median off-treatment duration was 16.3 months (95% confidence interval [CI] 12.3-20.3 months) and 18.5 months (95% CI 12.5-23.0 months) in the curcumin and placebo groups, respectively. There was no significant difference in the curve of off-treatment duration between the two groups (P = 0.4816). The proportion of patients with PSA progression during the active curcumin treatment period (6 months) was significantly lower in the curcumin group than the placebo group (10.3% vs 30.2%, P = 0.0259). The change of PSA, testosterone levels during 6 months, and HRQOL scores at 6 months were not different between curcumin and placebo groups. Adverse events were higher in the placebo group (16 of 46 vs 7 of 45 patients, P = 0.0349). No significant differences in the adverse drug reaction were found between the two groups.

CONCLUSIONS

Six months' intake of oral curcumin did not significantly affect the overall off-treatment duration of IAD. However, PSA elevation was suppressed with curcumin intake during the curcumin administration period. Curcumin at this dose was well tolerated and safe.

Curcumin reverses doxorubicin resistance via inhibition the efflux function of ABCB4 in doxorubicin‑resistant breast cancer cells

Doxorubicin is one of the most widely used chemotherapy agents for the treatment of breast cancer. However, the development of doxorubicin resistance limits the long-term treatment benefits in patients with breast cancer. Curcumin, a well-known dietary polyphenol derived from the rhizomes of turmeric (Curcuma longa), enhances the sensitivity of breast cancer cells to chemotherapeutic agents; however, the mechanisms underlying this phenomenon remain unclear. The aim of the present study was to evaluate the effect of curcumin on chemoresistance in doxorubicin-resistant breast cancerMCF-7/DOX and MDA-MB-231/DOX cell lines. Cell Counting Kit-8, monolayer transport, western blot and ATPase activity assays were performed during the study. The results revealed that curcumin significantly enhanced the effect of doxorubicin in doxorubicin-resistant breast cancer cells. The intracellular accumulation of doxorubicin was substantially increased following curcumin treatment in doxorubicin-resistant breast cancer cells, in a manner that was inversely dependent on the activity of ATP binding cassette subfamily B member 4 (ABCB4). Treatment with a combination of curcumin and doxorubicin decreases the efflux of doxorubicin in ABCB4-overexpressing cells. Furthermore, curcumin inhibited the ATPase activity of ABCB4 without altering its protein expression. In conclusion, curcumin reversed doxorubicin resistance in human breast cancer MCF-7/DOX and MDA-MB-231/DOX cells by inhibiting the ATPase activity of ABCB4. The study highlights the promising use of curcumin as a chemosensitizer in the treatment of breast cancer.

Basic principles of drug delivery systems - the case of paclitaxel

Cancer is the second cause of death worldwide, exceeded only by cardiovascular diseases. The prevalent treatment currently used against metastatic cancer is chemotherapy. Among the most studied drugs that inhibit neoplastic cells from acquiring unlimited replicative ability (a hallmark of cancer) are the taxanes. They operate via a unique molecular mechanism affecting mitosis. In this review, we show this mechanism for one of them, paclitaxel, and for other (non-taxanes) anti-mitotic drugs. However, the use of paclitaxel is seriously limited (its bioavailability is <10%) due to several long-standing challenges: its poor water solubility (0.3 μg/mL), its being a substrate for the efflux multidrug transporter P-gp, and, in the case of oral delivery, its first-pass metabolism by certain enzymes. Adequate delivery methods are therefore required to enhance the anti-tumor activity of paclitaxel. Thus, we have also reviewed drug delivery strategies in light of the various physical, chemical, and enzymatic obstacles facing the (especially oral) delivery of drugs in general and paclitaxel in particular. Among the powerful and versatile platforms that have been developed and achieved unprecedented opportunities as drug carriers, microemulsions might have great potential for this aim. This is due to properties such as thermodynamic stability (leading to long shelf-life), increased drug solubilization, and ease of preparation and administration. In this review, we define microemulsions and nanoemulsions, analyze their pertinent properties, and review the results of several drug delivery carriers based on these systems.

Curcumin alleviates rheumatoid arthritis-induced inflammation and synovial hyperplasia by targeting mTOR pathway in rats

PURPOSE

Rheumatoid arthritis (RA) is a chronic, progressive autoimmune disease characterized by aggressive and symmetric polyarthritis. Mammalian target of rapamycin (mTOR) was reported to be a new target for RA therapy and its inhibitor rapamycin can significantly reduce the invasive force of fibroblast-like synoviocytes. Here, we determined the effect of curcumin to alleviate inflammation and synovial hyperplasia for the therapy of RA.

MATERIALS AND METHODS

Collagen-induced arthritis (CIA) was developed in Wistar rats and used as a model resembling RA in humans. Rats were treated with curcumin (200 mg/kg) and the mTOR inhibitor rapamycin (2.5 mg/kg) daily for 3 weeks. Effects of the treatment on local joint, peripheral blood, and synovial hyperplasia in the pathogenesis of CIA were analyzed.

RESULTS

Curcumin and rapamycin significantly inhibited the redness and swelling of ankles and joints in RA rats. Curcumin inhibited the CIA-induced mTOR pathway and the RA-induced infiltration of inflammatory cells into the synovium. Curcumin and rapamycin treatment inhibited the increased levels of proinflammatory cytokines including IL-1β, TNF-α, MMP-1, and MMP-3 in CIA rats.

CONCLUSION

Our findings show that curcumin alleviates CIA-induced inflammation, synovial hyperplasia, and the other main features involved in the pathogenesis of CIA via the mTOR pathway. These results provide evidence for the anti-arthritic properties of curcumin and corroborate its potential use for the treatment of RA.

Molecular targets of curcumin in breast cancer (Review)

Curcumin (diferuloylmethane), an orange‑yellow component of turmeric or curry powder, is a polyphenol natural product isolated from the rhizome of Curcuma longa. For centuries, curcumin has been used in medicinal preparations and as a food colorant. In recent years, extensive in vitro and in vivo studies have suggested that curcumin possesses activity against cancer, viral infection, arthritis, amyloid aggregation, oxidation and inflammation. Curcumin exerts anticancer effects primarily by activating apoptotic pathways in cancer cells and inhibiting pro‑cancer processes, including inflammation, angiogenesis and metastasis. Curcumin targets numerous signaling pathways associated with cancer therapy, including pathways mediated by p53, Ras, phosphatidylinositol‑3‑kinase, protein kinase B, Wnt‑β catenin and mammalian target of rapamycin. Clinical studies have demonstrated that curcumin alone or combined with other drugs exhibits promising anticancer activity in patients with breast cancer without adverse effects. In the present review, the chemistry and bioavailability of curcumin and its molecular targets in breast cancer are discussed. Future research directions are discussed to further understand this promising natural product.

Curcumin attenuates resistance to irinotecan via induction of apoptosis of cancer stem cells in chemoresistant colon cancer cells

Resistance to conventional chemotherapeutic agents, including irinotecan (CPT‑11), 5-fluorouracil and capecitabine is a major cause for therapeutic failure in patients with colorectal cancer (CRC). Increasing evidence has demonstrated that cancer cells exhibiting stem cell-like characteristics are associated with the development of resistance to chemotherapeutic agents. As a plant polyphenol, curcumin has been demonstrated to have the ability to ameliorate resistance of CRC to chemotherapeutic agents, but the associations among curcumin, cancer stem cells (CSCs) and chemoresistance of CRC remain unclear. The present study established a CPT‑11-resistant colon cancer cell line, LoVo/CPT‑11 cells, and detected the expression levels of CSC identification markers [cluster of differentiation (CD)44, CD133, epithelial cell adhesion molecule (EpCAM) and CD24] in parental cells and CPT‑11-resistant cells. It was revealed that the expression levels of the colon CSC markers in LoVo/CPT‑11 cells were significantly higher compared those in parental cells at the mRNA and protein level. The effect of curcumin on the chemoresistance to CPT‑11 and the expression levels of CSC identification markers in LoVo/CPT‑11 cells separately treated with curcumin and CPT‑11 were further investigated. The results revealed that curcumin significantly attenuated chemoresistance to CPT‑11, and treatment with curcumin resulted in a significant reduction of the expression levels of CSC identification markers. Furthermore, a tumor sphere formation assay was used to enrich colon CSCs from LoVo/CPT‑11 cells, and demonstrated that curcumin efficiently diminished the traits of colon CSCs, as evidenced by the inability to form tumor spheres, the reduction in the expression of CSC identification markers, and apoptosis-induced effects on sphere-forming cells treated with curcumin alone or in combination with CPT‑11. Altogether, the present data demonstrated that curcumin attenuated resistance to chemotherapeutic drugs through induction of apoptosis of CSCs among colon cancer cells. These findings may provide novel evidence for the therapeutic application of curcumin in CRC intervention.

New curcumin-derived ligands and their affinity towards Ga3+, Fe3+ and Cu2+: spectroscopic studies on complex formation and stability in solution

Chemico-physical properties, metal chelating ability, antiproliferative activity and DNA binding of new curcuminoids with improved stability.