Korean Red Ginseng Extract Enhances the Anticancer Effects of Imatinib Mesylate Through Abrogation p38 and STAT5 Activation in KBM-5 Cells.

Although imatinib mesylate (IM) in the treatment of chronic myelogenous leukemia (CML) remains the best example of successful targeted therapy, majority of patients with CML suffer its toxicity profile and develop chemoresistance to existing therapeutic agents. Thus, there is a need to develop novel alternative therapies for the treatment of CML. Here, we investigated whether Korean red ginseng extract (KRGE) could suppress the proliferation and induce chemosensitization in human CML cells. Also, we used a human phospho-antibody array containing 46 antibodies against signaling molecules to examine a subset of phosphorylation events after treatment. Korean red ginseng extract broadly suppressed the proliferation of five different cell lines, but KRGE was found to be the most potent inducer of apoptosis against KBM-5 cells. It also abrogated the expression of Bcl-2 (B-cell lymphoma 2), Bcl-xL (B-cell lymphoma-extra large), survivin, inhibitors of apoptosis protein 1/2, COX-2 (Cyclooxygenase-2), cyclin D1, matrix metalloproteinase-9, and VEGF (Vascular endothelial growth factor), as well as upregulated the expression of pro-apoptotic gene products. Interestingly, KRGE also enhanced the cytotoxic and apoptotic effect of IM in KBM-5 cells. The combination treatment of KRGE and IM caused pronounced suppression of p38 and signal transducer and activator of transcription 5 phosphorylation and induced phosphorylation of p53 compared with the individual treatment. Our results demonstrate that KRGE can enhance the anticancer activity of IM and may have a substantial potential in the treatment of CML.

Brassinin induces apoptosis in PC-3 human prostate cancer cells through the suppression of PI3K/Akt/mTOR/S6K1 signaling cascades.

The oncogenic PI3K/Akt/mammalian target of rapamycin (mTOR) signaling axis and its downstream effector, the ribosomal protein S6 kinase 1 (S6K1) play a key role in mediating cell survival in various tumor cells. Here, we investigated the effects of brassinin (BSN), a phytoalexin first identified as a constituent of cabbage, on the PI3K/Akt/mTOR/S6K1 activation, cellular proliferation, and apoptosis in PC-3 human prostate cancer. BSN exerted a significant dose-dependent cytotoxicity and reduced constitutive phosphorylation of Akt against androgen-independent PC-3 cells as compared to androgen-dependent LNCaP cells. Moreover, knockdown of androgen receptor (AR) by small interfering RNA enhanced the potential effect of BSN on induction of apoptosis in LNCaP cells. BSN clearly suppressed the constitutive activation of PI3K/Akt/mTOR/S6K1 signaling cascade, which correlated with the induction of apoptosis as characterized by accumulation of cells in subG1 phase, positive Annexin V binding, TUNEL staining, loss of mitochondrial membrane potential, down-regulation of antiapoptotic and proliferative proteins, activation of caspase-3, and cleavage of PARP. Additionally, BSN could block broad-spectrum inhibition of PI3K/Akt/mTOR/S6K1 axes, and aberrant Akt activation by pcDNA3-myr-HA-Akt1 plasmid could not prevent the observed suppressive effect of BSN on constitutive mTOR activation. Finally, overexpression of Bcl-2 also attenuated BSN-mediated apoptosis in PC-3 cells. Taken together, our findings suggest that BSN can interfere with multiple signaling cascades involved in tumorigenesis and might be provided as a potential therapeutic candidate for both the prevention and treatment of prostate cancer.

Anti-metastatic effect of supercritical extracts from the Citrus hassaku pericarp via inhibition of C-X-C chemokine receptor type 4 (CXCR4) and matrix metalloproteinase-9 (MMP-9).

The fruit of hassaku (Citrus hassaku Hort. ex Tanaka) is locally known as phalsak in Korea. Recently, the fruit extract has been known to exhibit in vivo preventive effects against UVB-induced pigmentation, antiallergic activity, and enhancement of blood fluidity. However, the exact mechanisms of how supercritical extracts of phalsak peel (SEPS) inhibits tumor metastasis and invasion are still not fully understood. We found that SEPS could downregulate the constitutive expression of both CXCR4 and HER2 in human breast cancer MDA-MB-231 cells as compared with other cells. SEPS also suppressed matrix metalloproteinase-9 (MMP-9) expression and its enzymatic activity under non-cytotoxic concentrations. Neither proteasome inhibition nor lysosomal stabilization had any effect on the SEPS-induced decrease in CXCR4 expression. A detailed study of the underlying molecular mechanisms revealed that the regulation of the downregulation of CXCR4 was at the transcriptional level, as indicated by downregulation of mRNA expression, suppression of NF-κB activity, and inhibition of chromatin immunoprecipitation activity. Suppression of CXCR4 expression by SEPS correlated with the inhibition of CXCL12-stimulated invasion of MDA-MB-231 cells. Overall, our results indicate, for the first time, that SEPS can suppress CXCR4 and MMP-9 expressions through blockade of NF-κB activation and thus has the potential to suppress metastasis of breast cancer.

Embelin inhibits growth and induces apoptosis through the suppression of Akt/mTOR/S6K1 signaling cascades.

BACKGROUND: Akt/mTOR/S6K1 signaling cascades play an important role both in the survival and proliferation of tumor cells. METHODS: In the present study, we investigated the effects of embelin (EB), identified primarily from the Embelia ribes plant, on the Akt/mTOR/S6K1 activation, associated gene products, cellular proliferation, and apoptosis in human prostate cancer cells. RESULTS: EB exerted significant cytotoxic and suppressive effects on Akt and mTOR activation against androgen-independent PC-3 cells as compared to androgen-dependent LNCaP cells. Moreover, EB suppressed the constitutive activation of Akt/mTOR/S6K1 signaling cascade, which correlated with the induction of apoptosis as characterized by accumulation of cells in subG1 phase, positive Annexin V binding, down-regulation of anti-apoptotic (Bcl-2, Bcl-xL, survivin, IAP-1, and IAP-2) and proliferative (cyclin D1) proteins, activation of caspase-3, and cleavage of PARP. We also observed that EB can significantly enhance the apoptotic effects of a specific pharmacological Akt inhibitor when used in combination and also caused broad inhibition of all the three kinases in Akt/mTOR/S6K1 signaling axis in PC-3 cells. CONCLUSIONS: EB inhibits multiple signaling cascades involved in tumorigenesis and can be used as a potential therapeutic candidate for both the prevention and treatment of prostate cancer.

Chrysanthemum indicum L. extract induces apoptosis through suppression of constitutive STAT3 activation in human prostate cancer DU145 cells.

Chrysanthemum indicum L. has been shown to possess antiinflammatory and anticancer activities, but its molecular targets/pathways are not yet fully understood in tumor cells. In the present study, the potential effects of C. indicum on signal transducer and activator of transcription 3 (STAT3) signaling pathway in different tumor cells were examined. The solvent fractions (hexane, CH2Cl2, EtOAc, and BuOH,) were obtained from a crude extract (80% EOH extract) of C. indicum. The methylene chloride fraction of C. indicum (MCI) exhibited strong cytotoxic activity as compared with the other fractions and clearly suppressed constitutive STAT3 activation against both DU145 and U266 cells, but not MDA-MB-231 cells. The suppression of constitutive STAT3 activation by MCI is associated with blocking upstream JAK1 and JAK2, but not Src. MCI downregulated the expression of STAT3-regulated gene products; this is correlated with the accumulation of the cell cycle at sub-G1 phase, the induction of caspase-3 activation, and apoptosis. Moreover, the major components of the MCI were bioactive compounds such as sudachitin, hesperetin, chrysoeriol, and acacetin. Sudachitin, chrysoeriol, and acacetin also exerted significantly cytotoxicity, clearly suppressed constitutive STAT3 activation, and induced apoptosis, although hesperetin did not show any significant effect in DU145 cells. Overall, our results demonstrate that MCI could induce apoptosis through inhibition of the JAK1/2 and STAT3 signaling pathways.

Capillarisin inhibits iNOS, COX-2 expression, and proinflammatory cytokines in LPS-induced RAW 264.7 macrophages via the suppression of ERK, JNK, and NF-κB activation.

The aerial parts of Artemisia capillaris (Compositae) have been used in traditional Korean medicine as a cholagogic, antipyretic, anti-inflammatory, and diuretic purposes. In our previous study, ethanolic extracts of the plant demonstrated a marked anti-inflammatory effect in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells (J. Korean Soc. Appl. Biol. Chem., 2010, 53, 275-282). In the present study, capillarisin (CPS), a flavone, main constituent of A. capillaris, was examined for its anti-inflammatory activity in the cells. We found that CPS highly suppressed LPS-induced nitric oxide (NO) without exerting cytotoxic effects on RAW 264.7 cells. CPS inhibited the expression of LPS-induced inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) protein and their mRNA in a dose-dependent manner. Also, tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1ß, and prostaglandin E(2) (PGE(2)) secretion were decreased by CPS in LPS-stimulated macrophages. As a result, CPS inhibited proinflammatory cytokines, iNOS, and COX-2, which is attributed to the suppression of LPS-induced ERK, JNK, and nuclear factor-κB (NF-κB) activation. Therefore, we demonstrate here that CPS potentially inhibits the biomarkers related to inflammation through the abrogation of ERK, JNK, and NF-κB p65 activation, and it may be a potential therapeutic candidate for the treatment of inflammatory diseases.

The butanol fraction of guava (Psidium cattleianum Sabine) leaf extract suppresses MMP-2 and MMP-9 expression and activity through the suppression of the ERK1/2 MAPK signaling pathway.

The leaf extract of guava (Psidium cattleianum Sabine) has traditionally been used for the treatment of diarrhea and diabetes in East Asia and other countries. Recently, the leaf extract has been employed in the therapy of cancer, bacterial infections, and inflammation in experimental models. However, the exact mechanisms of how guava leaf extract inhibits tumor metastasis and invasion are still unknown. In the present study, we investigated in detail the molecular mechanism(s) responsible for the potential antimetastatic and antiinvasive effects of the butanol fraction of guava leaf extract (GBF). Interestingly, we observed for the first time that GBF suppressed both matrix metalloproteinases (MMP)-9 and MMP-2 expression and activity in part through the downregulation of the ERK1/2 activation in lung cancer cells. Also, importantly, the major components of the GBF were identified as d-glucuronic acid, quercetin 3-glucuronide, loganin, and xanthyletin by LC-ESI-MS/MS. Collectively, our data indicate that the guava leaf could reduce the metastasis of lung cancer cells and therefore suggest that it could be advantageously used to control the metastatic process.

Improvement of atopic dermatitis-like skin lesions by Platycodon grandiflorum fermented by Lactobacillus plantarum in NC/Nga mice.

Atopic dermatitis (AD) is characterized as a multi-factorial inflammatory skin disease that has been increasing worldwide. Previously, we demonstrated that FPG, which is Platycodon grandiflorum (PG) fermented by Lactobacillus plantarum (LP), increases the level of interferon (IFN)-gamma in mouse splenocytes in vitro. In this study, we investigated the effects of FPG in an animal model of AD, with a particular emphasis on its effects on T helper (Th)1 and Th2 immune responses. To assess the potential use of FPG for the inhibition of AD, we established a model of AD-like skin lesions in NC/Nga mice. Immunoglobulin isotypes (Igs) and Th1/Th2 cytokines in the sera and spleens of AD-like mice were examined. In addition, histological examination was also performed. AD symptoms in skin lesions improved following oral administration of FPG. IgE secretion was significantly down-regulated, and this was accompanied by decreased levels of interleukin (IL)-4 and IgG1 and increased serum levels of IL-12p40 and IgG2a in FPG-treated animals. In splenocytes, the production of the Th1 cytokines IL-12p40 and IFN-gamma was up-regulated, while the levels of the Th2 cytokines IL-4 and 5 were down-regulated by FPG treatment. These results suggest that FPG inhibits the development of AD-like skin lesions in NC/Nga mice by suppressing the Th2 cell response and increasing the Th1 cell responses. Our results indicate that FPG is safe and effective for the prevention of AD-like skin lesions.

Polygoni Rhizoma inhibits inflammatory response through inactivation of nuclear factor-kappaB and mitogen activated protein kinase signaling pathways in RAW264.7 mouse macrophage cells.

The objective of this study was to determine the antiinflammatory effects of Polygoni Rhizoma (PR), an Oriental medicinal herb, in interleukin 1 beta (IL-1ß) and lipopolysaccharide (LPS)-stimulated RAW264.7 mouse macrophage cells. PR significantly reduced the production of pro-inflammatory cytokines such as IL-6, tumor necrosis factor alpha (TNF-α) and pro-inflammatory mediators such as inducible nitric oxide synthase (iNOS), nitric oxide (NO), cyclooxygenase 2 (COX-2) and prostaglandin E2 (PGE2) even at a concentration of 1 µg/mL in the cells. In addition, PR inhibited the transcriptional activity of NF-κB as well as the degradation and phosphorylation of inhibitory kappa B alpha (IκBα). Furthermore, PR suppressed the phosphorylation of extracellular signal regulated kinase 1/2 (ERK1/2), p38 and c-Jun N-terminal kinase 1/2 (JNK1/2) in IL-1ß and LPS-treated RAW264.7. The results suggest that PR exerts an antiinflammatory property by inhibiting iNOS, COX-2, TNF-α and IL-6 production in association with inactivation of the NF-κB and MAPK signaling pathways in RAW 264.7 cells.

Inhibition of LPS-induced inflammatory biomarkers by ethyl acetate fraction of Patrinia scabiosaefolia through suppression of NF-κB activation in RAW 264.7 cells.

Patrinia scabiosaefolia (PS) has been used for curing various types of inflammatory-related disorders. However, the precise mechanism of the anti-inflammatory activity of PS remains unclear. Here, we investigated the anti-inflammatory effects of several fractions isolated from the PS in RAW 264.7 macrophages. The results indicated that the ethyl acetate fraction of PS (EAPS) concentration highly suppressed lipopolysaccharide (LPS)-induced nitric oxide (NO) and IL-6 productions without a cytotoxic effect on RAW 264.7 cells. EAPS inhibited the expressions of LPS-induced iNOS and COX-2 protein and their mRNA in a dose-dependent manner. Particularly, EAPS suppressed the level of nuclear factor-κB (NF-κB) activity, which was linked with the suppression of LPS-induced phosphorylation of p65 at serine 276 and p65 translocation into nuclei, but not MAPK signaling. In addition, treatment with EAPS inhibited the production of TNF-α in LPS-injected mice and suppressed the production of IL-6 and TNF-α in LPS-stimulated splenocytes from BALB/c mice. Therefore, we demonstrate here that Patrinia scabiosaefolia potentially inhibits the biomarkers related to inflammation through the blocking of NF-κB p65 activation, and it may be a potential therapeutic candidate for the treatment of inflammatory diseases.

Anti-inflammatory activities of Reynoutria elliptica through suppression of mitogen-activated protein kinases and nuclear factor-κB activation pathways.

Reynoutria elliptica has been used in traditional Korean medicine to promote blood circulation, relieve pain, increase dieresis, and alleviate respiratory problems, through as yet undefined mechanisms. We set out to determine whether the anti-inflammatory effects of this plant are linked with its ability to suppress mitogen-activated protein kinases (MAPKs) and nuclear factor-κB (NF-κB) activation in lipopolysaccharide (LPS)-activated RAW 264.7 cells. We found for the first time that the hexane fraction of Reynoutria elliptica (HRE) significantly inhibited LPS-stimulated NO and PGE2 synthesis. This is due to the diminishing of the mRNA and protein expression of iNOS and COX-2, respectively. HRE also suppressed LPS-stimulated TNF-α secretion in a dose-dependent manner, which might be due to the suppression of LPS-induced MAPKs and NF-κB activation. Moreover, our HPLC data demonstrated that the major components of the HRE were bioactive compounds such as emodin-6-Glc, emodin, and physcion. Overall, our results indicate that Reynoutria elliptica could be provided as a potential candidate for anti-inflammation treatment.

Emodin inhibits invasion and migration of prostate and lung cancer cells by downregulating the expression of chemokine receptor CXCR4.

Emodin (ED), an anthraquinone derivative, has been found to inhibit proliferation, induce apoptosis, suppress angiogenesis, impede metastasis, and enhance chemotherapy. However, the detailed mechanism of ED related to the regulation of CXC chemokine receptor-4 (CXCR4) gene expression that affects cellular migration and invasion in prostate and lung cancer cells are not fully understood. Recent evidence indicates that the CXCR4/CXCL12 axis is involved in promoting invasion and metastasis in tumors. Thus, novel agents that can downregulate CXCR4 expression have therapeutic potential in repressing cancer metastasis. Among ED and its derivatives, it is found that ED downregulated the expression of both CXCR4 and HER2 without affecting cell viability in tumor cells. The suppression of CXCR4 expression by ED was found to correlate with the inhibition of CXCL12-induced migration and invasion of both DU145 and A549 cells. Besides, neither proteasome inhibition nor lysosomal stabilization had any effect on ED-induced decrease in CXCR4 expression. The basic molecular mechanisms unveiled that the downregulation of CXCR4 was at the transcriptional level, as indicated by downregulation of mRNA expression and suppression of NF-κB activation. Overall, our findings suggest that ED is a novel blocker of CXCR4 expression and, thus, has enormous potential as a powerful therapeutic agent for metastatic cancer.

Antimetastatic effect of nobiletin through the down-regulation of CXC chemokine receptor type 4 and matrix metallopeptidase-9.

CONTEXT: Nobiletin is one of the citrus bioflavonoids and can be found in citrus fruits such as lemons, oranges, tangerines, and grapefruits. The most studied properties of nobiletin are its anti-inflammatory and anticancer activities. OBJECTIVE: The exact mechanisms of how nobiletin inhibits tumor metastasis and invasion are still not fully understood. In this study, we screened various natural compounds to down-modulate the CXC chemokine receptor-4 (CXCR4) and matrix metallopeptidase-9 (MMP-9). MATERIALS AND METHODS: The effect of nobiletin on the constitutive expressions of CXCR4 and MMP-9, MMP-9 enzymatic activity, associated nuclear factor κB (NF-κB) and mitogen-activated protein kinases (MAPKs) activation, and tumor cell invasion in human breast cancer cells was investigated. CXCR4 and MMP-9 expression were evaluated via reverse transcription polymerase chain reaction (RT-PCR) and western blotting. NF-κB activation was also evaluated by electrophoretic mobility shift assay (EMSA). In addition, the antimetastatic effects of nobiletin were determined by gelatin zymography and invasion assay. RESULTS: Nobiletin down-regulated both the constitutive expressions of CXCR4 and MMP-9 in human breast cancer cells with IC(50) values of 32 and 24 µM, respectively. Nobiletin also suppressed MMP-9 enzymatic activity and tumor cell invasion under noncytotoxic concentrations. Neither proteasome inhibition nor lysosomal stabilization had any effect on the nobiletin-induced decrease in CXCR4 expression. A detailed study of the underlying molecular mechanisms revealed that the regulation of the down-regulation of CXCR4 and MMP-9 were at the transcriptional level, as indicated by the down-regulation of mRNA expression and the suppression of the constitutive NF-κB and MAPKs activation. DISCUSSION AND CONCLUSION: Our results indicate, for the first time, that nobiletin is a novel blocker of CXCR4 and MMP-9 expressions and thus has the potential to suppress metastasis of breast cancer.

Oral administration of penta-O-galloyl-ß-D-glucose suppresses triple-negative breast cancer xenograft growth and metastasis in strong association with JAK1-STAT3 inhibition.

There is an urgent clinical need for chemotherapeutic and chemopreventive drugs for triple-negative breast cancer (TNBCa). Extending on our recent work, we hypothesize that the herbal compound 1,2,3,4,6-penta-O-galloyl-beta-D-glucose (PGG) can inhibit the growth and metastasis of TNBCa xenograft and target Janus-activated kinase (JAK)-signal transducer and activator of transcription (STAT) 3-signaling axis. Daily oral gavage of 10 mg PGG/kg body wt decreased MDA-MB-231 xenograft weight by 49.3% (P < 0.01) at 40 days postinoculation, whereas weekly intraperitoneal injections of Taxol at the same dosage resulted in a 21.4% reduction (P > 0.1). PGG treatment also decreased the incidence of lung metastasis. Immunohistochemical staining detected decreased Ki-67 (proliferation) index and increased terminal deoxynucleotidyl transferase deoxyuridine triphosphate nick end labeling (apoptosis) index in PGG-treated and Taxol-treated xenografts. However, the CD34 (angiogenesis) index was decreased only in PGG-treated xenografts along with decreased phospho-STAT3. In cell culture of MDA-MB-231 cells, PGG decreased pSTAT3 and its downstream target proteins, decreased its upstream kinase pJAK1 and induced the expression of SHP1, a JAK1 upstream tyrosine phosphatase, within as early as 1 h of exposure. The phosphatase inhibitor pervanadate reversed the PGG-induced downregulation of pSTAT3 and caspase activation. Orally administered PGG can inhibit TNBCa growth and metastasis, probably through anti-angiogenesis, antiproliferation and apoptosis induction. Mechanistically, PGG-induced inhibition of JAK1-STAT3 axis may contribute to the observed in vivo efficacy and the effects on the cellular processes.

Melatonin promotes puromycin-induced apoptosis with activation of caspase-3 and 5'-adenosine monophosphate-activated kinase-alpha in human leukemia HL-60 cells.

Melatonin, a naturally occurring molecule, is produced by the pineal gland in a circadian manner to regulate biologic rhythms in humans. Recent studies report that melatonin may be an attractive candidate as an anticancer agent or for combined therapy because of its antioxidant, oncostatic and immunoregulatory activities. In this study, the potentiating effect of melatonin was evaluated on the apoptosis induced by puromycin as an anticancer drug in acute promyelocytic leukemia HL-60 cells. Melatonin did not show significant cytotoxicity against HL-60 cells compared to puromycin. However, melatonin significantly augmented the cytotoxicity of puromycin. Consistently, combined treatment of melatonin and puromycin reduced the expression of anti-apoptotic proteins, such as bcl-2 and bcl-x(L) , and also induced caspase-3 activation and poly (ADP-ribose) polymerase (PARP) cleavage compared to puromycin treatment alone. Furthermore, cell cycle analysis revealed that melatonin promoted puromycin-induced apoptosis by increasing the sub-G1 population, but suppressing G2/M arrest in HL-60 cells. Interestingly, melatonin activated the phosphorylation of 5'-adenosine monophosphate-activated kinase (AMPK) in combination with puromycin. Taken together, our results suggest that melatonin potentiates puromycin-induced apoptosis with caspase-3 and AMPK activation in HL-60 cells, and thus, melatonin treatment can be effectively applied to leukemia treatment as a potential sensitizer for chemotherapeutic agents.

Inhibitory effect of Platycodon grandiflorum on T(H)1 and T(H)2 immune responses in a murine model of 2,4-dinitrofluorobenzene-induced atopic dermatitis-like skin lesions.

BACKGROUND: Platycodon grandiflorum is a traditional Asian medicine that is used to treat pulmonary and respiratory allergic disorders. OBJECTIVE: to investigate the effects of P grandiflorum in vivo in an animal model of atopic dermatitis (AD), with particular emphasis on its effects on T(H)1 and T(H)2 immune responses. METHODS: we established a model of AD-like skin lesions in NC/Nga mice. After oral administration of P grandiflorum, we measured cytokine and immunoglobulin profiles along with histologic examination of skin. RESULTS: P grandiflorum was nontoxic in a 2,4-dinitrofluorobenzene-induced model of AD-like skin lesions in NC/Nga mice. AD symptoms in skin lesions improved after oral administration of P grandiflorum. IgE secretion was significantly downregulated in P grandiflorum-treated animals, accompanied by decreased levels of interleukin (IL) 4 and IgG1 and increased serum levels of IL-12p40 and IgG2a. In isolated splenocytes, the production of the T(H)1 cytokines IL-12p40 and interferon-γ was upregulated by P grandiflorum, whereas the levels of the T(H)2 cytokines IL-4 and IL-5 were downregulated in a mouse model of AD-like skin lesions. CONCLUSIONS: these results suggest that P grandiflorum inhibits the development of AD-like skin lesions in NC/Nga mice by suppressing the T(H)2 cell response and increasing the T(H)1 cell responses. Our results indicate that P grandiflorum is safe and effective as a natural herbal medicine for the treatment of AD-like skin lesions.

Rhapontigenin inhibited hypoxia inducible factor 1 alpha accumulation and angiogenesis in hypoxic PC-3 prostate cancer cells.

Hypoxia inducible factor 1 alpha (HIF-1α) is frequently over-expressed in the numerous types of cancer and plays an important role in angiogenesis. In the present study, the inhibitory mechanism of rhapontigenin isolated from Vitis coignetiae was investigated on HIF-1α stability and angiogenesis in human prostate cancer PC-3 cells. Rhapontigenin significantly suppressed HIF-1α accumulation at protein level but not at mRNA level in PC-3 cells under hypoxia. Also, rhapontigenin suppressed hypoxia-induced HIF-1α activation in various cancer cells, such as colorectal adenocarcinoma (SW620), breast adenocarcinoma (MCF-7), fibrosarcoma (HT-1080) and prostate carcinoma (LNCaP). Interestingly, rhapontigenin had more potency in inhibition of hypoxia-induced HIF-1α expression than that of resveratrol, a known HIF-1α inhibitor. In addition, rhapontigenin promoted hypoxia-induced HIF-1α degradation and cycloheximide (CHX) blocked protein synthesis. A prolyl hydroxylase (PHD) inhibitor dimethyloxalylglycine (DMOG) is usually utilized to examine whether prolyl hydroxylation is involved in inhibition of HIF-1α accumulation. Here, DMOG recovered HIF-1α accumulation inhibited by rhapontigenin. Immunoprecipitation assay also revealed that rhapotigenin enhanced the binding of hydroxylated HIF-1α to von Hippel-Lindau (VHL) tumor suppressor protein. Furthermore, rhapontigenin reduced vascular endothelial growth factor (VEGF) secretion in hypoxic PC-3 cells as well as suppressed tube formation in human umbilical vein endothelial cells (HUVECs) treated by the conditioned media of hypoxic PC-3 cells. However, anti-angiogenic effect of rhapontigenin in hypoxic PC-3 cells was reversed by DMOG. Taken together, these findings suggest that rhapontigenin inhibits HIF-1α accumulation and angiogenesis in PC-3 prostate cancer cells.

Cellular uptake of ginsenosides in Korean white ginseng and red ginseng and their apoptotic activities in human breast cancer cells.

Panax ginseng has been reported to have cancer-preventive properties and, through anti-inflammatory, antioxidant, and pro-apoptotic mechanisms, to influence gene expression. However, the comparison of Korean white ginseng (WG) and red ginseng (RG) in their apoptotic effects and the identification of the selective cellular uptake of the ginsenosides in human breast cancer cells have not yet been fully understood. In the present study, the relative nonpolar and protopanaxadiol (PPD) class ginsenosides exhibited more cytotoxic and efficient cellular uptake on MCF-7 cells compared with the relative polar and protopanaxatriol (PPT) class compounds. PPD class ginsenosides were present in RG in a 2.5 times higher concentration as compared to WG, while PPT class ginsenosides were only present in WG. Thus, RG exerted more potent cytotoxicity than WG against MCF-7 and MDA-MB231 cells. RG also increased the sub-G1 DNA contents of the cell cycle and Annexin V-positive apoptotic bodies undergoing apoptosis through the caspase-3 activation in MCF-7 cells. In addition, RG downregulated the proliferative and anti-apoptotic gene products and potentiated paclitaxel-induced apoptosis in MCF-7 cells. Overall, RG contained a higher concentration of PPD class ginsenosides as compared to WG; the greater cellular uptake of PPD resulted in more substantial antiproliferative activity in human breast cancer cells.

Ka-mi-kae-kyuk-tang oriental herbal cocktail attenuates cyclophosphamide-induced leukopenia side effects in mouse.

Ka-mi-kae-kyuk-tang (KMKKT) is an Oriental herbal medicinal cocktail and has been shown to have potent antiangiogenic, anticancer, and antimetastatic activities in preclinical animal models without observable side effects. We previously found that in prostate cancer xenograft experiments, treating tumor-bearing mice with KMKKT alleviated the body weight loss toward the end of the study, suggesting a general health-promoting activity. We investigated whether KMKKT alleviated cancer chemotherapy drug-induced leukopenia and other hematotoxicity in vivo using a mouse model. KMKKT was given once daily orally for 10 days to the mice before they were given cyclophosphamide (CPA) daily injection for 4 days. KMKKT blunted CPA-induced decrease in red blood cells, hemoglobin content, and the total white blood cell/leukocyte counts. Examination of the multiple organ sites involved in hematopoiesis, and lymphocyte differentiation and maturation showed the attenuated changes induced by CPA in each and every type of cells examined. Particularly, some of the cell types are fully restored in the bone marrow and even overstimulated in the Sca-1(+), CD117(+), or Sca1(+)/CD117(+) and CD34(+)/CD117(+) stem cells, supporting a role of KMKKT to stimulate hematopoietic stem cell (HSC) signaling to compensate for CPA-induced destruction of leukocytes and other cell types. Taken together, KMKKT might be a safe and effective herbal complementary and alternative medicine (CAM) modality to alleviate cancer drug-induced hematological side effects in addition to its anticancer activities. Preclinical investigations with other chemo- and radiation modalities are warranted to support planning translation consideration for human patients.

Hydrocinchonine, cinchonine, and quinidine potentiate paclitaxel-induced cytotoxicity and apoptosis via multidrug resistance reversal in MES-SA/DX5 uterine sarcoma cells.

Multidrug resistance (MDR) is one of important issues to cause the chemotherapy failure against cancers including gynecological malignancies. Despite some MDR reversal evidences of natural compounds including quinidine and cinchonine, there are no reports on MDR reversal activity of hydrocinchonine with its analogues quinidine and cinchonine especially in uterine sarcoma cells. Thus, in the current study, we comparatively investigated the potent efficacy of hydrocinchonine and its analogues quinidine and cinchonine as MDR-reversal agents for combined therapy with antitumor agent paclitaxel (TAX). Hydrocinchonine, cinchonine, and quinidine significantly increased the cytotoxicity of TAX in P-glycoprotein (gp)-positive MES-SA/DX5, but not in the P-gp-negative MES-SA cells at nontoxic concentrations by 3-(4,5-dimethylthiazol-2-yl)-2,5--diphenyltetrazolium bromide (MTT) assay. Rhodamine assay also revealed that hydrocinchonine, cinchonine, and quinidine effectively enhanced the accumulation of a P-gp substrate, rhodamine in TAX-treated MES-SA/DX5 cells compared with TAX-treated control. In addition, hydrocinchonine, cinchonine, and quinidine effectively cleaved poly (ADP-ribose) polymerase (PARP), activated caspase-3, and downregulated P-gp expression as well as increased sub-G1 apoptotic portion in TAX-treated MES-SA/DX5 cells. Taken together, hydrocinchonine exerted MDR reversal activity and synergistic apoptotic effect with TAX in MES-SA/DX5 cells almost comparable with quinidine and cinchonine as a potent MDR-reversal and combined therapy agent with TAX.