Biochemical mechanism of modulation of human P-glycoprotein (ABCB1) by curcumin I, II, and III purified from Turmeric powder

P-glycoprotein (Pgp, ABCB1) is an ATP-dependent drug efflux pump linked to development of multidrug resistance (MDR) in cancer cells. Previously [Biochem Pharmacol 2002;64:573-82], we reported that a curcumin mixture could modulate both function and expression of Pgp. This study focuses on the effect of three major curcuminoids--curcumin I, II and III purified from a curcumin mixture--on modulation of Pgp function in a multidrug resistant human cervical carcinoma cell line (KB-V1). The similar IC(50) values for cytotoxicity of curcuminoids of KB-V1, and KB-3-1 (parental drug sensitive cell line) suggest that these curcuminoids may not be substrates for Pgp. Treating the cells with non-toxic doses of curcuminoids increased their sensitivity to vinblastine only in the Pgp expressing drug resistant cell line, KB-V1, and curcumin I retained the drug in KB-V1 cells more effectively than curcumin II and III, respectively. Effects of each curcuminoid on rhodamine123, calcein-AM, and bodipy-FL-vinblastine accumulation confirmed these findings. Curcumin I, II and III increased the accumulation of fluorescent substrates in a dose-dependent manner, and at 15 microM, curcumin I was the most effective. The inhibitory effect in a concentration-dependent manner of curcuminoids on verapamil-stimulated ATPase activity and photoaffinity labeling of Pgp with the [(125)I]-iodoarylazidoprazosin offered additional support; curcumin I was the most potent modulator. Taken together, these results indicate that curcumin I is the most effective MDR modulator among curcuminoids, and may be used in combination with conventional chemotherapeutic drugs to reverse MDR in cancer cells.     

Production of monoclonal antibodies to P-glycoprotein: its application in detection of soluble and surface P-glycoprotein of leukemia patients

Multidrug resistance (MDR) in leukemia is commonly associated with the expression of a transmembrane protein, P-glycoprotein (P-gp). In this study, two monoclonal antibodies (mAbs) specific for the extracellular domain of P-gp were generated. By employing the generated mAbs, a two-color lysed whole blood flow cytometric method for surface P-gp and an efficient sandwich ELISA for soluble P-gp determinations were established. By using the established methods, surface and soluble P-gp were detected in several leukemia patients. The presence of soluble P-gp could be used to identify the P-gp surface expression patients. Detection of soluble P-gp reported provides a new basis that may lead to a better understanding of the MDR mechanism in leukemia.     

Anti-P-glycoprotein conjugated nanoparticles for targeting drug delivery in cancer treatment

Targeting therapeutics to specific sites can enhance the efficacy of drugs, reduce required doses as well as unwanted side effects. In this work, using the advantages of the specific affinity of an immobilized antibody to membrane P-gp in two different nanoparticle formulations were thus developed for targeted drug delivery to multi-drug resistant cervical carcinoma (KB-V1) cells. Further, this was compared to the human drug sensitive cervical carcinoma cell line (KB-3-1) cells. The two nanoparticle preparations were: NP1, anti-P-gp conjugated with poly (DL-lactic-coglycolic acid) (PLGA) nanoparticle and polyethylene glycol (PEG); NP2, anti-P-gp conjugated to a modified poloxamer on PLGA nanoparticles. The cellular uptake capacity of nanoparticles was confirmed by fluorescent microscopy. Comparing with each counterpart core particles, there was a higher fluorescence intensity of the targeted nanoparticles in KBV1 cells compared to KB-3-1 cells suggesting that the targeted nanoparticles were internalized into KB-V1 cells to a greater extent than KB-3-1 cell. The results had confirmed the specificity and the potential of the developed targeted delivery system for overcoming multi-drug resistance induced by overexpression of P-gp on the cell membrane.     

Inhibitory effect of curcumin onMDR1 gene expression in patient leukemic cells

When patients with cancers are treated with chemotherapeutic agents a long time, some of the cancer cells develop the multidrug resistance (MDR) phenotype. MDR cancer cells are characterized by the overexpression of multidrug resistance1(MDR1) gene which encodes P-glycoprotein (Pgp), a surface protein of tumor cells that functions to produce an excessive efflux and thereby an insufficient intracellular concentration of chemotherapeutic agents. A variety of studies have sought potent MDR modulators to decrease MDR1 gene expression in cancer cells. Our previous study has shown that curcumin exhibits characteristics of a MDR modulator in KB-V1 multidrug-resistant cells. The aim of this study was to further investigate the effect of curcumin on MDR1 gene expression in patient leukemic cells. The leukemic cells were collected from 78 childhood leukemia patients admitted at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai, Thailand, in the period from July 2003 to February 2005. There were 61 cases of acute lymphoblastic leukemia (ALL), 14 cases of acute myeloblastic leukemia (AML), and 3 cases of chronic myelocytic leukemia (CML). There were 47 males and 31 females ranging from 1 to 15 years old. Bone marrows were collected. The leukemic cells were separated and cultured in the presence or absence of 10 microM curcumin for 48 hours. MDR1 mRNA levels were determined by RT-PCR. It was found that curcumin reduced MDR1 gene expression in the cells from 33 patients (42%). Curcumin affected the MDR1 gene expression in 5 of 11 relapsed cases (45%), 10 of 26 cases of drug maintenance (38%), 7 of 18 cases of completed treatment (39%), and 11 of 23 cases of new patients (48%). The expression levels of MDR1 gene in leukemic patient cells as compared to that of KB-V1 cells were classified as low level (1-20%) in 5 of 20 cases (25%), medium level (21-60%) in 14 of 32 cases (44%), and high level (61-100%) in 14 of 20 cases (70%). In summary, curcumin decreased MDR1 mRNA level in patient leukemic cells, especially in high level of MDR1 gene groups. Thus, curcumin treatment may provide a lead for clinical treatment of leukemia patients in the future.     

Budgeting for a billion: applying health technology assessment (HTA) for universal health coverage in India

Background

India recently launched the largest universal health coverage scheme in the world to address the gaps in providing healthcare to its population. Health technology assessment (HTA) has been recognised as a tool for setting priorities as the government seeks to increase public health expenditure. This study aims to understand the current situation for healthcare decision-making in India and deliberate on the opportunities for introducing HTA in the country.

Methods

A paper-based questionnaire, adapted from a survey developed by the International Decision Support Initiative (iDSI), was administered on the second day of the Topic Selection Workshop that was conducted as part of the HTA Awareness Raising Workshop held in New Delhi on 25–27 July, 2016. Participants were invited to respond to questions covering the need, demand and supply for HTA in their context as well as the role of their organisation vis-à-vis HTA. The response rate for the survey was about 68% with 41 participants having completed the survey.

Results

Three quarters of the respondents (71%) stated that the government allocated healthcare resources on the basis of expert opinion. Most respondents indicated reimbursement of individual health technologies and designing a basic health benefit package (93% each) were important health policy areas while medical devices and screening programmes were cited as important technologies (98% and 92%, respectively). More than half of the respondents noted that relevant local data was either not available or was limited. Finally, technical capacity was seen as a strength and a constraint facing organisations.

Conclusion

The findings from this study shed light on the current situation, the opportunities, including potential topics, and challenges in conducting HTA in India. There are limitations to the study and further studies may need to be conducted to inform the role that HTA will play in the design or implementation of universal health coverage in India.

     

Inhibition of MMP-3 activity and invasion of the MDA-MB-231 human invasive breast carcinoma cell line by bioflavonoids

Aim:

Stromelysin 1 (matrix metalloproteinase 3; MMP-3) is an enzyme known to be involved in tumor invasion and metastasis. In this study, flavonoids from vegetables and fruits, such as quercetin, kaempferol, genistein, genistin, and daidzein, were tested for their ability to modulate the secretion and activity of MMP-3 in the MDA-MB-231 breast cancer cell line. In addition, we investigated the in vitro effects of flavonoids on MDA-MB-231 cell invasion.

Methods:

The toxic concentration range of flavonoids was evaluated using the MTT assay. The ability of MDA-MB-231 cells to invade was evaluated using a modified Boyden chamber system. The activity of MMP-3 was determined by casein zymography. The secretion of MMP-3 was evaluated using Western blotting, casein zymography and confirmed by ELISA.

Results:

Some putative flavonoids, ie, quercetin and kaempferol (flavonols), significantly inhibited the in vitro invasion of MDA-MB-231 cells in a concentration-dependent manner, with IC₅₀ values of 27 and 30 μmol/L, respectively. Quercetin and kaempferol also reduced MMP-3 activity in a dose-dependent manner, with IC₅₀ values in the range of 30 μmol/L and 45 μmol/L, respectively. None of the flavonoids had a significant effect on the secretion of MMP-3.

Conclusion:

These data show that the flavonols quercetin and kaempferol have higher anti-invasion potency and higher MMP-3 inhibitory activity than isoflavones genistein, genistin and daidzein. In contrast, neither flavonols nor isoflavones have any effect on MMP-3 secretion.     

The inhibitory effect of turmeric curcuminoids on matrix metalloproteinase-3 secretion in human invasive breast carcinoma cells

Matrix metalloproteinase-3 (MMP-3) is a key enzyme with important implications in the invasion and metastasis of breast cancer cells. Curcumin (Cur), demethoxycurcumin (DMC), and bisdemethoxycurcumin (BDMC) are major forms of curcuminoids found in turmeric powder with reported anticancer activity. This study focuses on the comparative effect of Cur, DMC and BDMC on the modulation of MMP-3 activity and its secretion in MDA-MB-231 breast cancer cells. MMP-3 levels were determined by casein zymography, ELISA and western blotting. Analysis of MMP-3 expression by casein zymography revealed high expression in MDA-MB-231 invasive breast carcinoma cells, but not in MCF-7 non-invasive breast cancer cells. ELISA assays showed MMP-3 levels were significantly decreased in all curcuminoid treatments. Using zymography, treatment with non-toxic doses revealed that every curcuminoid compound except Cur reduced MMP-3 levels. Moreover, the result from western blot analysis confirmed that only DMC and BDMC reduced MMP-3 secretion in MDA-MB-231 cells, but Cur did not have any effect. MMP-3 activity revealed that none of the curcuminoids showed significant effects. However, treatment of the cells with Cur, DMC and BDMC exhibited a significant inhibition of cell invasion and motility with DMC and BDMC being more potent. These results suggest that Cur, DMC, and BDMC may be used as MMP-3 inhibitors to modulate MMP-3 expression.     

Inhibitory effect of curcumin onWT1 gene expression in patient leukemic cells

Leukemias are common worldwide. Wilms' tumor1 (WT1) protein is highly expressed in leukemic blast cells of myeloid and lymphoid origin. Thus, WT1 mRNA serves as a tumor marker for leukemias detection and monitoring disease progression. Curcumin is well known for its anti-cancer property. The objective of this study was to investigate the effect of curcumin on WT1 gene expression in patient leukemic cells. The leukemic cells were collected from 70 childhood leukemia patients admitted at Maharaj Nakorn Chiang Mai Hospital, Chiang Mai, Thailand, in the period July 2003 to February 2005. There were 58 cases of acute lymphoblastic leukemia (ALL), 10 cases of acute myeloblastic leukemia (AML), and 2 cases of chronic myelocytic leukemia (CML). There were 41 males and 29 females ranging from 1 to 15 years old. Leukemic cells were cultured in the presence or absence of 10 mM curcumin for 48 h. WT1 mRNA levels were determined by RT-PCR. The result showed that curcumin reduced WT1 gene expression in the cells from 35 patients (50%). It affected the WT1 gene expression in 4 of 8 relapsed cases (50%), 12 of 24 cases of drug maintenance (50%), 7 of 16 cases of completed treatment (44%), and 12 of 22 cases of new patients (54%). The basal expression levels of WT1 gene in leukemic patient cells as compared to that of K562 cells were classified as low level (1-20%) in 6 of 20 cases (30%), medium level (21-60%) in 12 of 21 cases (57%), and high level (61-100%) in 17 of 23 cases (74%). In summary, curcumin decreased WT1 mRNA in patient leukemic cells. Thus, curcumin treatment may provide a lead for clinical treatment in leukemic patients in the future.     

Investigation of fruit peel extracts as sources for compounds with antioxidant and antiproliferative activities against human cell lines

The aim of this study was to evaluate antioxidant activity and cytotoxicity against human cell lines of fruit peel extracts from rambutan, mangosteen and coconut. The highest antioxidant activity was found from rambutan peel crude extract where the highest radical scavenging capacity via ABTS assay was from its ethyl acetate fraction with a TEAC value of 23.0 mM/mg and the highest ferric ion reduction activity via FRAP assay was from its methanol fraction with an EC value of 20.2 mM/mg. Importantly, using both assays, these fractions had a higher antioxidant activity than butylated hydroxyl toluene and vitamin E. It was shown that the ethyl acetate fraction of rambutan peel had the highest polyphenolic content with a gallic acid equivalent of 2.3 mg/mL. The results indicate that the polyphenolic compounds are responsible for the observed antioxidant activity of the extracts. Interestingly, the hexane fraction of coconut peel showed a potent cytotoxic effect on KB cell line by MTT assay (IC₅₀ = 7.7 μg/mL), and no detectable cytotoxicity toward normal cells. We concluded that the ethyl acetate fraction of rambutan peel is a promising resource for potential novel antioxidant agents whereas the hexane fraction of coconut peel may contain novel anticancer compounds.