Pornsiri Pitchakarn

Enhancement of cellular uptake and cytotoxicity of curcumin-loaded PLGA nanoparticles by conjugation with anti-P-glycoprotein in drug resistance cancer cells

Aim:To compare the anti-cancer activity and cellular uptake of curcumin (Cur) delivered by targeted and non-targeted drug delivery systems in multidrug-resistant cervical cancer cells.Methods:Cur was entrapped into poly (DL-lactide-co-glycolide) (PLGA) nanoparticles (Cur-NPs) in the presence of modified-pluronic F127 stabilizer using nano-precipitation technique. On the surface of Cur-NPs, the carboxy-terminal of modified pluronic F127 was conjugated to the amino-terminal of anti-P-glycoprotein (P-gp) (Cur-NPs-APgp). The physical properties of the Cur-NPs, including particle size, zeta potential, particle morphology and Cur release kinetics, were investigated. Cellular uptake and specificity of the Cur-NPs and Cur-NPs-APgp were detected in cervical cancer cell lines KB-V1 (higher expression of P-gp) and KB-3-1 (lower expression of P-gp) using fluorescence microscope and flow cytometry, respectively. Cytotoxicity of the Cur-NPs and Cur-NPs-APgp was determined using MTT assay.Results:The particle size of Cur-NPs and Cur-NPs-APgp was 127 and 132 nm, respectively. The entrapment efficiency and actual loading of Cur-NPs-APgp (60% and 5 μg Cur/mg NP) were lower than those of Cur-NPs (99% and 7 μg Cur/mg NP). The specific binding of Cur-NPs-APgp to KB-V1 cells was significantly higher than that to KB-3-1 cells. Cellular uptake of Cur-NPs-APgp into KB-V1 cells was higher, as compared to KB-3-1 cells. However, the cellular uptake of Cur-NPs and Cur-NPs-IgG did not differ between the two types of cells. Besides, the cytotoxicity of Cur-NPs-APgp in KB-V1 cells was higher than those of Cur and Cur-NPs.Conclusion:The results demonstrate that Cur-NPs-APgp targeted to P-gp on the cell surface membrane of KB-V1 cells, thus enhancing the cellular uptake and cytotoxicity of Cur.

Induction of G1 arrest and apoptosis in androgen-dependent human prostate cancer by Kuguacin J, a triterpenoid from Momordica charantia leaf.

In this study, we focused on the effects of a bitter melon (Momordica charantia) leaf extract (BMLE) and a purified component, Kuguacin J (KuJ), on androgen-dependent LNCaP human prostate cancer cells. Both treatments exerted growth inhibition through G1 arrest and induction of apoptosis. In addition, KuJ markedly decreased the levels of cyclins (D1 and E), cyclin-dependent kinases (Cdk2 and Cdk4) and proliferating cell nuclear antigen, and caused an increase in p21 and p27 levels. Its induction of apoptosis was accompanied by an increase in cleavage of caspase-3 and poly (ADP-ribose) polymerase, attributable to augment of Bax/Bcl-2 and Bad/Bcl-xL and reduction of survivin levels. BMLE and KuJ also reduced the expression of androgen receptor (AR), prostate-specific antigen (PSA) while induced P53 protein level. Down-regulation of p53 by RNA interference indicated that BMLE and KuJ inhibited cell growth partly through p53-dependent cell cycle arrest and apoptotic pathways. Both BMLE and KuJ caused less toxicity in a normal prostate cell line, PNT1A. Our results suggest that BMLE and a purified component, KuJ, from its diethyl ether fraction could be promising candidate new antineoplastic and chemopreventive agents for androgen-dependent prostate cancer and carcinogenesis.

Momordica charantia leaf extract suppresses rat prostate cancer progression in vitro and in vivo

Cancer metastasis is a major cause of death in cancer patients, with invasion as a first step greatly contributing to the failure of clinical treatments. Any compounds with an inhibitory influence on this process are therefore of prime interest. Momordica charantia (bitter melon) is widely consumed as a vegetable and especially as a folk medicine in Asia. Here, we investigated the anti‐invasive effects of bitter melon leaf extract (BMLE) on a rat prostate cancer cell line (PLS10) in vitro and in vivo. The results indicated that non‐toxic concentrations of BMLE significantly inhibited the migration and invasion of cells in vitro. The results of zymography showed that BMLE inhibited the secretion of MMP‐2, MMP‐9 and urokinase plasminogen activator (uPA) from PLS10. Real‐time RT‐PCR revealed that BMLE not only significantly decreased gene expression of MMP‐2 and MMP‐9, but also markedly increased the mRNA level of TIMP‐2, known to have inhibitory effects on the activity of MMP‐2. An EnzChek gelatinase/collagenase assay showed that collagenase type IV activity was partially inhibited by BMLE. In the in vivo study, intravenous inoculation of PLS10 to nude mice resulted in a 100% survival rate in the mice given a BMLE‐diet as compared with 80% in the controls. The incidence of lung metastasis did not show any difference, but the percentage lung area occupied by metastatic lesions was slightly decreased in the 0.1% BMLE treatment group and significantly decreased with 1% BMLE treatment as compared with the control. Thus, the results indicate for the first time an anti‐metastatic effect of BMLE both in vitro and in vivo. (Cancer Sci 2010)

Silencing of connexin 43 suppresses invasion, migration and lung metastasis of rat hepatocellular carcinoma cells

To reduce cancer mortality, understanding of mechanisms of cancer metastasis is crucial. We have established six rat hepatocellular carcinoma (HCC) cell lines, which exhibit differing metastatic potential to the lung after inoculation into the tail veins of nude mice. In the present experiment, we investigated the process of cell attachment to metastatic sites and possible regulating factors. One hour after inoculation, two of two HCC cell lines with high metastatic potential and one of two HCC cell lines with low metastatic potential exhibited many attached cells in the lung. One day after inoculation, lung metastatic foci were observed only with highly‐metastatic cells with elevated connexin 43 (Cx43) expression as assessed by cDNA array analysis. Furthermore, 24 or 48 h after transfection of an siRNA targeting Cx43, in vitro invasion and migration were suppressed by 68% (P < 0.001) and 36% (P < 0.05) compared with control‐siRNA transfected cells, despite no differences in cellular morphology, cell proliferation or apoptotic activity. Moreover, the number of metastatic nodules per lung area in nude mice was significantly (P < 0.01) reduced. In conclusion, suppression of Cx43 expression in tumor cells reduced in vitro migration and invasion capacity and in vivo metastatic ability so that Cx43 has potential as a molecular target for prevention of cancer metastasis with Cx43 overexpressing tumors. (Cancer Sci 2012; 103: 860–867)

Suppression of Inflammatory Responses by Black Rice Extract in RAW 264.7 Macrophage Cells via Downregulation of NF-kB and AP-1 Signaling Pathways.

Anthocyanin, a phenolic compound, has been reported to have an anti-inflammatory effect against lipopolysaccharide (LPS) induced changes in immune cells. However, little is known about the molecular mechanisms underlying its anti-inflammatory effects. Few research studies have concerned the anti-inflammation properties of colored rice extract as a functional material. Therefore, the purpose of this study was to examine anti-inflammatory effects of the polar fraction of black rice whole grain extracts (BR-WG-P) that features a high anthocyanin content. Our results showed that BR-WG-P significantly inhibited LPS-induced pro- inflammatory mediators, including production of NO and expression of iNOS and COX-2. In addition, secretion of pro-inflammatory cytokines including TNF-α and IL-6 was also significantly inhibited. Moreover, BR-WG-P and anthocyanin inhibited NF-kB and AP-1 translocation into the nucleus. BR-WG-P also decreased the phosphorylation of ERK, p38 and JNK in a dose dependent manner. These results suggested that BR-WG-P might suppress LPS-induced inflammation via the inhibition of the MAPK signaling pathway leading to decrease of NF-kB and AP-1 translocation. All of these results indicate that BR-WG-P exhibits therapeutic potential associated with the anthocyanin content in the extract for treating inflammatory diseases associated with cancer.

Ellagic Acid Inhibits Migration and Invasion by Prostate Cancer Cell Lines

Polyphenolic compounds from pomegranate fruit extracts (PFEs) have been reported to possess antiproliferative, pro-apoptotic, anti-inflammatory and anti-invasion effects in prostate and other cancers. However, the mechanisms responsible for the inhibition of cancer invasion remain to be clarified. In the present study, we investigated anti-invasive effects of ellagic acid (EA) in androgen-independent human (PC-3) and rat (PLS10) prostate cancer cell lines in vitro. The results indicated that non-toxic concentrations of EA significantly inhibited the motility and invasion of cells examined in migration and invasion assays. The EA treatment slightly decreased secretion of matrix metalloproteinase (MMP)-2 but not MMP-9 from both cell lines. We further found that EA significantly reduced proteolytic activity of collagenase/gelatinase secreted from the PLS-10 cell line. Collagenase IV activity was also concentration-dependently inhibited by EA. These results demonstrated that EA has an ability to inhibit invasive potential of prostate cancer cells through action on protease activity.

Kuguacin J isolated from Momordica charantia leaves inhibits P-glycoprotein (ABCB1)-mediated multidrug resistance.

Multidrug resistance (MDR) is a major factor in the failure of chemotherapy in cancer patients. Resistance to chemotherapy has been correlated to the overexpression of ABC drug transporters including P-glycoprotein (P-gp) that actively efflux chemotherapeutic drugs from cancer cells. Our previous study showed that bitter melon (Momordica charantia) leaf extract (BMLE) was able to reverse the MDR phenotype by increasing the intracellular accumulation of chemotherapeutic drugs. In the present study, bioguided fractionation was used to identify the active component(s) of BMLE that is able to modulate the function of P-gp and the MDR phenotype in a human cervical carcinoma cell line (KB-V1). We found that kuguacin J, one of the active components in BMLE, increased sensitivity to vinblastine and paclitaxel in KB-V1 cells. A flow cytometry assay indicated that kuguacin J inhibits the transport function of P-gp and thereby significantly increases the accumulation of rhodamine 123 and calcein AM in the cells. These results were confirmed by [³H]-vinblastine transport assay. Kuguacin J significantly increases intracellular [³H]-vinblastine accumulation and decreased the [³H]-vinblastine efflux in the cells. Kuguacin J also inhibited the incorporation of [¹²⁵I]-iodoarylazidoprazosin into P-gp in a concentration-dependent manner, indicating that kuguacin J directly interacts with the drug-substrate-binding site on P-gp. These results indicate that kuguacin J modulates the function of P-gp by directly interacting at the drug-substrate-binding site, and it appears to be an effective inhibitor of P-gp activity in vitro and thus could be developed as an effective chemosensitizer to treat multidrug-resistant cancers.

Ellagic acid, a component of pomegranate fruit juice, suppresses androgen-dependent prostate carcinogenesis via induction of apoptosis

Ellagic acid (EA), a component of pomegranate fruit juice (PFJ), is a plant‐derived polyphenol and has antioxidant properties. PFJ and EA have been reported to suppress various cancers, including prostate cancer. However, their chemopreventive effects on development and progression of prostate cancer using in vivo models have not been established yet.

Kuguacin J, a triterpeniod from Momordica charantia leaf, modulates the progression of androgen-independent human prostate cancer cell line, PC3

In this study, we focused on the in vitro effects of Kuguacin J (KuJ), a purified component of bitter melon (Momordica charantia) leaf extract (BMLE), on the androgen-independent human prostate cancer cell line PC3 and the in vivo effect of dietary BMLE on prostate carcinogenesis using a PC3-xenograph model. KuJ exerted a strong growth-inhibitory effect on PC3 cells. Growth inhibition was mainly through G1-arrest: KuJ markedly decreased the levels of cyclins (D1 and E), cyclin-dependent kinases (Cdk2 and Cdk4) and proliferating cell nuclear antigen. Interestingly, KuJ also dramatically decreased the levels of survivin expressed by PC3 cells. In addition, KuJ exerted anti-invasive effects on PC3 cells, significantly inhibiting migration and invasion: KuJ inhibited secretion of the active forms of MMP-2, MMP-9 and uPA by PC3 cells. In addition, KuJ treatment significantly decreased the expression of membrane type 1-MMP (MT1-MMP) by PC3 cells. In vivo, 1% and 5% BMLE in the diet resulted in 63% and 57% inhibition of PC3 xenograft growth without adverse effect on host body weight. Our results suggest that KuJ is a promising new candidate chemopreventive and chemotherapeutic agent for prostate cancer.

Apocynin, an NADPH oxidase inhibitor, suppresses progression of prostate cancer via Rac1 dephosphorylation.

Recently, considerable evidence has been generated that oxidative stress contributes to the etiology and pathogenesis of prostate cancer. The present study focused on the effects of apocynin, an inhibitor of the NADPH oxidase which generates intracellular superoxide, on a rat androgen-independent prostate cancer cell line (PLS10) in vitro and in vivo. Apocynin significantly inhibited cell proliferation of PLS10 cells via G1 arrest of the cell cycle in vitro. Surprisingly, it did not affect reactive oxygen species (ROS) but inhibited phosphorylation of Rac1, one component of the NADPH oxidase complex. A Rac1 inhibitor, NSC23766, also inhibited cell proliferation, and both apocynin and NSC23766 reduced phosphorylation of Rac1 and NF-κB, as well as cyclin D1. Furthermore, in a xenograft model of prostate cancer with PLS10, apocynin suppressed tumor growth and metastasis in a dose dependent manner in vivo, with reduction of cell proliferation and vessel number in the tumors. Expression and secretion of vascular endothelial growth factor (VEGF) were reduced by apocynin treatment in vivo and in vitro, respectively. In conclusion, despite no apparent direct relationship with oxidative stress, apocynin inhibited growth of androgen-independent prostate cancer in vitro and in vivo. Apocynin thus warrants further attention as a potential anti-tumor drug.