Tumor 5-FU-related mRNA Expression and Efficacy of Oral Fluoropyrimidines in Adjuvant Chemotherapy of Colorectal Cancer.

BACKGROUND: It has not been elucidated whether the clinical efficacy of oral fluoropyrimidines for adjuvant chemotherapy of colorectal cancer varies with tumor biological characteristics. PATIENTS AND METHODS: A multicenter randomized trial was performed comparing oral tegafur/gimeracil/oteracil (S-1) and uracil-tegafur/ leucovorin (UFT/LV) as adjuvant therapy for stage III colorectal cancer. Postoperative survival was compared based on the 5-FU-related mRNA levels in cancer tissues. RESULTS: Among patients with tumor expressing dihydropyrimidine dehydrogenase (DPD) mRNA within the 66.7th percentile (lower 2/3) of all cases, overall survival (OS) was significantly better in the S-1 than in the UFT/LV group. In the S-1 group, patients with low DPD-expressing tumors had significantly better OS than those with highly expressing tumors. Patients with low thymidine synthase (TS)-expressing tumors had significantly better OS than those with highly expressing tumors. CONCLUSION: The efficacy of oral fluoropyrimidines as adjuvant chemotherapy for colorectal cancer may be influenced by the level of 5-FU-related mRNA in cancer tissues.

Monooxygenase system in Guerin's carcinoma of rats under conditions of ω-3 polyunsaturated fatty acids administration.

The aim of the study was to determine the variations of function in components of monooxygenase system (MOS) of rat Guerin's carcinoma under ω-3 polyunsaturated fatty acids (PUFAs) administration. The activity of Guerin's carcinoma microsomal NADH-cytochrome b5 reductase, the content and the rate of cytochrome b5 oxidation-reduction, the content and the rate of cytochrome Р450 oxidation-reduction have been investigated in rats with tumor under conditions of ω-3 PUFAs administration. ω-3 PUFAs supplementation before and after transplantation of Guerin's carcinoma resulted in the increase of NADH-cytochrome b5 reductase activity and decrease of cytochrome b5 level in the Guerin's carcinoma microsomal fraction in the logarithmic phases of carcinogenesis as compared to the tumor-bearing rats. Increased activity of NADH-cytochrome b5 reductase facilitates higher electron flow in redox-chain of MOS. Under decreased cytochrome b5 levels the electrons are transferred to oxygen, which leads to heightened generation of superoxide (O2•-) in comparison to control. It was shown, that the decrease of cytochrome P450 level in the Guerin's carcinoma microsomal fraction in the logarithmic phases of oncogenesis under ω-3 PUFAs administration may be associated with its transition into an inactive form ­ cytochrome P420. This decrease in cytochrome P450 coincides with increased generation of superoxide by MOS oxygenase chain.

Marsdenia tenacissima extract induces G0/G1 cell cycle arrest in human esophageal carcinoma cells by inhibiting mitogen-activated protein kinase (MAPK) signaling pathway.

Marsdenia tenacissima extract (MTE, trade name: Xiao-Ai-Ping injection) is an extract of a single Chinese plant medicine. It has been used for the treatment of cancer in China for decades, especially for esophageal cancer and other cancers in the digestive tract. In the present study, the potential mechanism for MTE's activity in esophageal cancer was explored. The effects of MTE on the proliferation of human esophageal cancer cells (KYSE150 and Eca-109) were investigated by the MTT assay, the BrdU (bromodeoxyuridine) incorporation immunofluorescence assay, and flow cytometric analysis. MTE inhibited cell proliferation through inducing G0/G1 cell cycle arrest in KYSE150 and Eca-109. Western blot analysis was employed to determine protein levels in the MTE treated cells. Compared with the control cells, the expression levels of the cell cycle regulatory proteins cyclin D1/D2/D3, cyclin E1, CDK2/4/6 (CDK: cyclin dependent kinase), and p-Rb were decreased significantly in the cells treated with MTE at 40 mg·mL(-1). In addition, MTE had an inhibitory effect on the MAPK (mitogen-activated protein kinase) signal transduction pathway, including ERK (extracellular signal-regulated kinase), JNK (c-Jun N-terminal kinase), and p38MAPK. Moreover, MTE showed little additional effects on the regulation of cyclin D1/D3, CDK4/6, and p-Rb when the ERK pathway was already inhibited by the specific ERK inhibitor U0126. In conclusion, these data suggest that MTE inhibits human esophageal cancer cell proliferation through regulation of cell cycle regulatory proteins and the MAPK signaling pathways, which is probably mediated by the inhibition of ERK activation.

Aqueous extract of Taxus chinensis (Pilger) Rehd inhibits lung carcinoma A549 cells through the epidermal growth factor receptor/mitogen-activated protein kinase pathway in vitro and in vivo.

OBJECTIVE: To explore the anticancer mechanism of aqueous extract of Taxus Chinensis (Pilger) Rehd (AETC). METHODS: The serum pharmacological method was used to avoid interference from administration of the crude medicinal herbs. Eight purebred New Zealand rabbits were used for preparation of serum containing various concentrations of AETC. Forty-eight Balb/c-nu mice were used for in vivo experiments. The effects of serum containing AETC on the proliferation of A549 cells and expression levels of the epidermal growth factor receptor/mitogen-activated protein kinase (EGFR/MAPK) pathway-related proteins in vitro were investigated. Additionally, the effects on the growth of A549 xenografts in nude mice, and expression levels of the EGFR/MAPK pathway-related proteins in the xenografts, were investigated. RESULTS: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay revealed that the serum containing AETC significantly decreased the viability of A549 cells in a dose-dependent manner. Western blot showed that the serum containing various concentrations of AETC strongly reduced the levels of phospho-Jun N-terminal kinase (p-JNK) and phospho-extracellular signal-regulated kinasel/2 (ERK1/2) while it increased the level of p-p38. However, no significant effects on the expression levels of JNK, ERK1/2, and p38 MAPK were found. In addition, an anticancer effect from AETC was observed in vivo in the Balb/c-nu mice bearing A549 xenografts. CONCLUSION: AETC has significant effects on the growth of A549 xenografts and on the activity of the EGFR/MAPK pathway. Therefore, AETC may be beneficial in lung carcinoma treatment.

Down-regulating overexpressed human Lon in cervical cancer suppresses cell proliferation and bioenergetics.

The human mitochondrial ATP-dependent Lon protease functions in regulating the metabolism and quality control of proteins and mitochondrial DNA (mtDNA). However, the role of Lon in cancer is not well understood. Therefore, this study was undertaken to investigate the importance of Lon in cervical cancer cells from patients and in established cell lines. Microarray analysis from 30 cancer and 10 normal cervical tissues were analyzed by immunohistochemistry for Lon protein levels. The expression of Lon was also examined by immunoblotting 16 fresh cervical cancer tissues and their respective non-tumor cervical tissues. In all cases, Lon expression was significantly elevated in cervical carcinomas as compared to normal tissues. Augmented Lon expression in tissue microarrays did not vary between age, tumor-node-metastasis grades, or lymph node metastasis. Knocking down Lon in HeLa cervical cancer cells by lentivrial transduction resulted in a substantial decrease in both mRNA and protein levels. Such down-regulation of Lon expression significantly blocked HeLa cell proliferation. In addition, knocking down Lon resulted in decreased cellular bioenergetics as determined by measuring aerobic respiration and glycolysis using the Seahorse XF24 extracellular flux analyzer. Together, these data demonstrate that Lon plays a potential role in the oncogenesis of cervical cancer, and may be a useful biomarker and target in the treatment of cervical cancer. Lon; immunohistochemistry; cervical cancer; cell proliferation; cellular bioenergetics.

Anti-proliferative and matrix metalloproteinase-2 inhibition of Longkong (Lansium domesticum) extracts on human mouth epidermal carcinoma.

CONTEXT: Longkong [Lansium domesticum Corr. (Meliaceae)] is a popular tropical plant producing economic edible fruits found mainly in Southeast Asia. However, limited information is available concerning anticancer activity of Longkong. OBJECTIVE: To investigate anticancer activities in human mouth epidermal carcinoma (KB) of Longkong extracts. MATERIALS AND METHODS: Various parts of Longkong which was collected from Northern and Eastern of Thailand were extracted by the hot and cold processes using water, chloroform, and methanol. The extracts were tested for anti-oxidative activities and anti-proliferation as well as matrix metalloproteinase inhibition on KB cells. RESULTS: The hot water extract of seeds from Northern region (NSEWH), the cold water extract of old leaves from Northern region (NOLWC), and the hot chloroform extract of young leaves from Eastern region (EYLCH) showed the highest free radical scavenging, metal ion chelating, and lipid peroxidation inhibition with SC50, MC50 and IPC50 values of 0.34 ± 0.03, 0.47 ± 1.60 and 0.86 ± 0.31 mg/ml, respectively. The hot and cold chloroform extract of young fruits from Northern region (NYFCH and NYFCC) exhibited anti-proliferation effect against KB cells with IC50 values of 603.45 ± 55.35 and 765.06 ± 46.19 mg/ml, respectively. NYFCC exhibited the highest pro- and active MMP-2 inhibition at 53.03 ± 2.65 and 31.30 ± 0.43%, more than all tested standard anticancer drugs except cisplatin. DISCUSSION AND CONCLUSION: The cold chloroform extract of young fruits from Northern region appeared to contain anticancer active compounds against KB cells because of its high anti-proliferation and MMP-2 inhibition activities.

Teng-Long-Bu-Zhong-Tang, a Chinese herbal formula, enhances anticancer effects of 5--Fluorouracil in CT26 colon carcinoma.

BACKGROUND: Colorectal cancer remains one of the leading causes of cancer death worldwide. Traditional Chinese Medicine (TCM) has played a positive role in colorectal cancer treatment. There is a great need to establish effective herbal formula for colorectal cancer treatment. Based on TCM principles and clinical practices, we have established an eight herbs composed formula for colorectal cancer treatment, which is Teng-Long-Bu-Zhong-Tang (TLBZT). We have demonstrated the anticancer effects of TLBZT against colorectal carcinoma in vitro. In present study, we evaluated the anticancer potential of TLBZT, used alone or in combination with low dose of 5-Fluorouracil (5-Fu), in CT26 colon carcinoma in vivo. METHODS: CT26 colon carcinoma was established in BALB/c mice and treated with TLBZT, 5-Fu, or TLBZT plus 5-Fu. The tumor volumes were observed. Apoptosis was detected by TUNEL assay. Caspases activities were detected by colorimetric assay. Cell senescence was indentified by senescence ß-galactosidase staining. Gene expression and angiogenesis was observed by immunohistochemistry or western blot. RESULTS: TLBZT significantly inhibited CT26 colon carcinoma growth. TLBZT elicited apoptosis in CT26 colon carcinoma, accompanied by Caspase-3, 8, and 9 activation and PARP cleavage, and downregulation of XIAP and Survivin. TLBZT also induced cell senescence in CT26 colon carcinoma, with concomitant upregulation of p16 and p21 and downregulation of RB phosphorylation. In addition, angiogenesis and VEGF expression in CT26 colon carcinoma was significantly inhibited by TLBZT treatment. Furthermore, TLBZT significantly enhanced anticancer effects of 5-Fu in CT26 colon carcinoma. CONCLUSIONS: TLBZT exhibited significantly anticancer effect, and enhanced the effects of 5-Fu in CT26 colon carcinoma, which may correlate with induction of apoptosis and cell senescence, and angiogenesis inhibition. The present study provides new insight into TCM approaches for colon cancer treatment that are worth of further study.

[The induction of Guerin's carcinoma cytochrome p450 hydroxylase activity by retinoids].

The interconnection of tumor growth process and the provision of the body with vitamin A was studied. The replenishment of vitamin A stores of vitamin-deficient tumor bearing animals modulated Guerin's carcinoma growth rate in a dose dependent manner (r = 0,83). The morphological parameters of tumor growth at different provision with vitamin A positively correlated with hydroxylase (r = 0,81) and demethylase (r = 0,49) activities of the Guerin's carcinoma cytochrome P450 system. The induction of hydroxylase and demethylase activities of cytochrome P450 in Guerin's carcinoma microsomal fraction, observed either under conditions of overdose supplementation, or selective liposomal form of all-trans-retinoic acid, suggests the stimulatory effect of retinoids on tumor growth.

Anti-invasive activity of ethanol extracts of Ganoderma lucidum through tightening of tight junctions and inhibition of matrix metalloproteinase activities in human gastric carcinoma cells.

This study investigated the effect of ethanol extracts of Ganoderma lucidum (EGL) on the correlation between tightening of the tight junctions (TJs) and the anti-invasive activity in human gastric adenocarcinoma AGS cells to elucidate further the possible anticancer mechanisms that G lucidum exerts. Within the concentrations of EGL that were not cytotoxic, EGL markedly inhibited the cell motility and invasiveness in a concentration-dependent manner. The activities of matrix metalloproteinases (MMP)-2 and MMP-9 in AGS cells were dose-dependently inhibited by treatment with EGL, and this was correlated with a decrease in expression of their mRNA and proteins and the upregulation of the expression of the tissue inhibitors of metalloproteinases. The anti-invasive activity of EGL was also found to be associated with the increased tightness of the TJ, which was demonstrated by an increase in transepithelial electrical resistance. Additionally, EGL repressed the levels of the claudin family members, which are major components of TJs that play a key role in the control and selectivity of paracellular transport. Furthermore, the levels of E-cadherin, a type I transmembrane glycoprotein, were inhibited by EGL treatment, however, those of snail, an epithelial to mesenchymal transition regulator and zinc finger transcription factor, were concentration-dependently increased in response to EGL treatment. Although further studies are needed, the present study indicates that TJs and MMPs are crucial targets of EGL-induced anti-invasiveness in human gastric cancer AGS cells.

Inhibition of Rho-associated coiled-coil containing protein kinase enhances the activation of epidermal growth factor receptor in pancreatic cancer cells.

BACKGROUND: Rho-associated coiled-coil containing protein kinase (Rho-kinase/ROCK) is involved in various cellular functions including cell proliferation, and is generally considered to be oncogenic, while some studies show that ROCK functions as a negative regulator of cancer progression. As a result, the precise role of ROCK remains controversial. We have previously reported that Rho-kinase/ROCK negatively regulates epidermal growth factor (EGF)-induced cell proliferation in SW480 colon cancer cells. In the present study, we investigated the role of ROCK in EGF receptor (EGFR) signaling in the pancreatic cancer cell lines, Panc1, KP3 and AsPc1. RESULTS: In these cells, Y27632, a specific ROCK inhibitor, enhanced EGF-induced BrdU incorporation. The blockade of EGF stimulation utilizing anti-EGFR-neutralizing antibodies suppressed Panc1 cell proliferation. EGF induced RhoA activity, as well as the phosphorylation of cofilin and myosin light chain (MLC), both targets of ROCK signaling, and Y27632 suppressed both of these processes, indicating that the phosphorylation of cofilin and MLC by EGF occurs through ROCK in Panc1 cells. EGF-induced phosphorylation of EGFR at tyrosine residues was augmented when the cells were pretreated with Y27632 or were subjected to gene silencing using ROCK-siRNA. We also obtained similar results using transforming growth factor-α. In addition, EGF-induced phosphorylation of p44/p42 mitogen-activated protein kinase and Akt were also enhanced by Y27632 or ROCK-siRNA. Moreover, an immunofluorescence microscope study revealed that pretreatment with Y27632 delayed EGF-induced internalization of EGFR. Taken together, these data indicate that ROCK functions to switch off EGFR signaling by promoting the internalization of the EGFR. CONCLUSIONS: While EGF first stimulates the activation of the EGFR and subsequently increases cancer cell proliferation, EGF concurrently induces the activation of ROCK, which then turns off the activated EGFR pathway via a negative feedback system.

Subamolide A, a component isolated from Cinnamomum subavenium, induces apoptosis mediated by mitochondria-dependent, p53 and ERK1/2 pathways in human urothelial carcinoma cell line NTUB1.

ETHNOPHARMACOLOGICAL RELEVANCE: Cinnamomum subavenium has long been used as a traditional Chinese medicine to treat carcinomatous swelling, abdominal pain and other diseases. AIM OF THE STUDY: The goal of this work was to study the cytotoxic effect of subamolide A, a constituent isolated from the stems of Cinnamomum subavenium Miq., and to extend its traditional use for clinical applications in treating human urothelial carcinoma. MATERIALS AND METHODS: Cytotoxic effect of subamolide A was determined by the MTT assay in NTUB1, T24, PC3 and SV-HUC-1 cells treated with various concentrations of subamolide A for three days. Apoptosis was detected by the change of cell morphology and flow cytometry analysis. The reactive oxygen species (ROS) level and mitochondria membrane potential (Δψm) were determined by flow cytometry. Western blot analysis was used to quantify the expression of apoptosis-related and stress-induced signaling molecules. RESULTS: Subamolide A selectively induced apoptosis in two cancerous human urothelial carcinoma cell lines (NTUB1 and T24) in comparison with normal immortalized uroepithelial cells (SV-HUC-1). Subamolide A reduced mitochondrial membrane potential (Δψm) and caused apoptosis of NTUB1 cells. Subamolide A increased Bax/Bcl-2 ratios, the amount of cytochrome c released from the mitochondria, caspase-3 and PARP cleavage, activated p53 and ERK1/2 and ultimately led to apoptosis in NTUB1 cells. Furthermore, a higher dose (10µM) of subamolide A synergistically enhanced the cytotoxicity of cisplatin and gemcitabine in NTUB1 cells. CONCLUSIONS: The current study demonstrated that subamolide A triggered the mitochondria-dependent apoptotic pathways and p53 and ERK1/2 activation in the human urothelial carcinoma cell line NTUB1. In addition, subamolide A synergistically enhanced cytotoxic effect of CDDP and Gem in NTUB1. These data suggested that subamolide A exhibited a potent anti-proliferation activity. This study supports the traditional use of Cinnamomum subavenium stems with a therapeutic potential for the treatment of human urothelial carcinoma.

Induction of apoptosis by ethanol extracts of Ganoderma lucidum in human gastric carcinoma cells.

Ganoderma lucidum, a well-known medicinal mushroom, is highly valued and commonly used in Oriental medicine. Although recent experimental data has revealed the proapoptotic potency of G. lucidum extracts, the underlying mechanisms of this apoptotic activity have not yet been studied in detail. In the present study, the effects of ethanol extracts of G. lucidum (EGL) on the growth of an AGS human gastric carcinoma cell line were investigated. We found that EGL treatment resulted in a dose and time-dependent significant decrease in the viability of AGS cells. This decreased viability was caused by apoptotic cell death, with observed chromatin condensation and an accumulation of apoptotic fraction. EGL treatment induced the expression of death receptor-related proteins such as death receptor 5 and tumor necrosis factor-related apoptosis-inducing ligand, which further triggered the activation of caspase-8 and the cleavage of Bid. In addition, the increase in apoptosis that was induced by EGL was correlated with activation of caspase-9 and -3, downregulation of IAP family proteins such as XIAP and survivin, and concomitant degradation of poly (ADP-ribose) polymerase. Moreover the activity of Akt was downregulated in EGL-treated cells, and the phosphatidylinositol-3 kinase/ Akt inhibitor LY294002 sensitized the cells to EGL-induced apoptosis. The results indicated that EGL induces the apoptosis of AGS cells through a signaling cascade of death receptor-mediated extrinsic, as well as mitochondria-mediated intrinsic, caspase pathways which are associated with inactivation of the Akt signal pathway.

Inhibition of tumor angiogenesis by the matrix metalloproteinase-activated anthrax lethal toxin in an orthotopic model of anaplastic thyroid carcinoma.

Patients with anaplastic thyroid carcinoma (ATC) typically succumb to their disease months after diagnosis despite aggressive therapy. A large percentage of ATCs have been shown to harbor the V600E B-Raf point mutation, leading to the constitutive activation of the mitogen-activated protein kinase pathway. ATC invasion, metastasis, and angiogenesis are in part dependent on the gelatinase class of matrix metalloproteinases (MMP). The explicit targeting of these two tumor markers may provide a novel therapeutic strategy for the treatment of ATC. The MMP-activated anthrax lethal toxin (LeTx), a novel recombinant protein toxin combination, shows potent mitogen-activated protein kinase pathway inhibition in gelatinase-expressing V600E B-Raf tumor cells in vitro. However, preliminary in vivo studies showed that the MMP-activated LeTx also exhibited dramatic antitumor activity against xenografts that did not show significant antiproliferative responses to the LeTx in vitro. Here, we show that the MMP-activated LeTx inhibits orthotopic ATC xenograft progression in both toxin-sensitive and toxin-resistant ATC cells via reduced endothelial cell recruitment and subsequent tumor vascularization. This in turn translates to an improved long-term survival that is comparable with that produced by the multikinase inhibitor sorafenib. Our results also indicate that therapy with the MMP-activated LeTx is extremely effective against advanced tumors with well-established vascular networks. Taken together, these results suggest that the MMP-activated LeTx-mediated endothelial cell targeting is the primary in vivo antitumor mechanism of this novel toxin. Therefore, the MMP-activated LeTx could be used not only in the clinical management of V600E B-Raf ATC but potentially in any solid tumor.

Pterostilbene inhibits lung cancer through induction of apoptosis.

BACKGROUND: Lung cancer remains the leading cause of cancer mortality in the United States. Resveratrol is a potent antioxidant found in grapes that inhibits several types of cancer, including lung cancer. Herein, we investigated the effects of pterostilbene, an analog of resveratrol found in blueberries, on lung cancer, in vitro. We hypothesized that pterostilbene would inhibit lung cancer cell growth in vitro by a pro-apoptotic mechanism. METHODS: Two lung cancer cell lines (NCI-H460 and SK-MES-1) were cultured using standard techniques. Cells were treated with increasing doses of pterostilbene (10-100 microM). Cell viability was measured at 24, 48, and 72h using a MTT assay. Apo-ONE Caspase-3/7 assay was used to evaluate caspase activity. T-test and two-way ANOVA were used for statistical analysis. RESULTS: Pterostilbene significantly decreased cell viability in lung cancer cells in a concentration- and time-dependent manner (P<0.001). Concentrations greater than 20 microM of pterostilbene produced significant growth inhibition by 72h (P<0.001). Apoptosis and caspase-3/7 activity were significantly increased by pterostilbene treatment (P<0.05). CONCLUSIONS: Pterostilbene inhibits growth via apoptosis induction in vitro. Further in vitro mechanistic studies and in vivo experiments are warranted to determine the potential role for pterostilbene in lung cancer treatment or prevention.

Tumor aromatase expression as a prognostic factor for local control in young breast cancer patients after breast-conserving treatment.

INTRODUCTION: We sought to determine whether the levels of expression of 17 candidate genes were associated with locoregional control after breast-conserving treatments of early-stage breast cancers in young, premenopausal women. METHODS: Gene expression was measured by using RT-PCR in the breast tumors of a series of 53 young (younger than 40 years), premenopausal patients. All treatments consisted of primary breast-conserving surgery followed by whole-breast radiotherapy (+/- regional lymph nodes) with or without systemic treatments (chemotherapy +/- hormone therapy). The median follow-up was 10 years. RESULTS: The 10-year locoregional control rate was 70% (95% CI, 57% to 87%). In univariate analysis, no clinical/pathologic prognostic factors were found to be significantly associated with decreased locoregional control. Expression of three genes was found to be significantly associated with an increased locoregional recurrence rate: low estrogen-receptor beta, low aromatase, and high GATA3. Two others were associated with only a trend (P < 0.10): low HER1 and SKP2. In multivariate analysis, only the absence of aromatase was significantly associated with an increased locoregional recurrence rate (P = 0.003; relative risk = 0.49; 95% CI 0.29 to 0.82). CONCLUSIONS: Recent data give credit to the fact that breast cancer in young women is a distinct biologic entity driven by special oncogenic pathways. Our results highlight the role of estrogen-signaling pathways (mainly CYP19/aromatase, GATA3, and ER-beta) in the risk of locoregional recurrence of breast cancer in young women. Confirmation in larger prospective studies is needed.

Apoptosis induction of human lung carcinoma cells by Chan Su (Venenum Bufonis) through activation of caspases.

Chan Su is a traditional Chinese medicine prepared from the dried white secretion of the auricular and skin glands of toads, and has been used as an oriental drug for the treatment of a number of diseases, including cancer. In this study, the potential of Chan Su (skin of Venenum Bufonis) to induce apoptosis in human lung carcinoma A549 cells was investigated. Treatment of A549 cells with skin of Venenum Bufonis resulted in the inhibition of cell growth and viability and the induction of apoptosis, which was shown by trypan blue counts, MTT assay, DAPI staining and flow cytometry analysis. The increase in apoptosis that was induced by skin of Venenum Bufonis was correlated with down-regulation of anti-apoptotic Bcl-2 expression, up-regulation of pro-apoptotic Fas ligand and death receptor 4, and a decrease in the mitochondrial membrane potential. Skin of Venenum Bufonis treatment induced the proteolytic activation of caspases and a concomitant degradation of poly(ADP-ribose)-polymerase and beta-catenin protein. Cleavage of Bid and a down-regulation of the inhibitor of apoptosis family proteins were also observed in skin of Venenum Bufonis-treated A549 cells. Data from this study indicates that SVB induces the apoptosis of A549 cells through a signaling cascade of death receptor-mediated extrinsic and mitochondria-mediated intrinsic caspase pathways.

Heterogeneity of receptor function in colon carcinoma cells determined by cross-talk between type I insulin-like growth factor receptor and epidermal growth factor receptor.

This study identifies a novel cross-talk paradigm between the type I insulin-like growth factor receptor (IGF1R) and epidermal growth factor receptor (EGFR) in colon cancer cells. IGF1R activation by ligand exposure in growth factor-deprived cells induces Akt activation in the FET, CBS, and GEO colon cancer cell lines. Investigation of IGF1R-mediated signaling pathways using small interfering RNA approaches indicated that, as expected, phosphatidylinositol 3'-kinase (PI3K) was activated by IGF1R. Mitogen-activated protein kinase (MAPK) activity as reflected by phospho-extracellular signal-regulated kinase (ERK) induction was not significantly activated until later times following release of these cells from growth factor deprivation stress. The appearance of phospho-ERK was proximal to EGFR activation. Treatment of cells with the PI3K inhibitor LY294002 before release from stress resulted in a concentration-dependent loss of EGFR activation, whereas treatment with the MAPK inhibitor PD98059 did not block EGFR activation, indicating that EGFR activation was downstream of the IGF1R/PI3K pathway. PD98059 inhibition of MAPK was associated with a concentration-dependent reduction in EGFR-mediated phospho-ERK. EGFR inhibitor blocked induction of phospho-ERK, showing that MAPK activity was a consequence of EGFR-mediated signaling. On the other hand, a small-molecule IGF1R inhibitor, PQIP, blocked Akt phosphorylation. The divergent signaling functions of IGF1R and EGFR suggested the potential for synergism by a combination of therapy directed at the two receptors. Combination treatment with PQIP and EGFR inhibitor Tarceva resulted in synergistic effects as indicated by combination index analysis in all three cell lines tested.

The effects of adiponectin and metformin on prostate and colon neoplasia involve activation of AMP-activated protein kinase.

Population studies provide evidence that obesity and insulin resistance are associated not only with elevated serum insulin levels and reduced serum adiponectin levels but also with increased risk of aggressive prostate and colon cancer. We show here that adiponectin activates AMP-activated protein kinase (AMPK) in colon (HT-29) and prostate (PC-3) cancer cells. These results are consistent with prior observations in myocytes, but we show that in epithelial cancer cells AMPK activation is associated with reduction in mammalian target of rapamycin activation as estimated by Ser(2448) phosphorylation, with reduction in p70S6 kinase activation as estimated by Thr(389) phosphorylation, with ribosomal protein S6 activation as estimated by Ser(235/236) phosphorylation, with reduction in protein translation as estimated by [(35)S]methionine incorporation, and with growth inhibition. Adiponectin-induced growth inhibition is significantly attenuated when AMPK level is reduced using small interfering RNA, indicating that AMPK is involved in mediating the antiproliferative action of this adipokine. Thus, adiponectin has the characteristics of a AMPK-dependent growth inhibitor that is deficient in obesity, and this may contribute to the adverse effects of obesity on neoplastic disease. Furthermore, metformin was observed to activate AMPK and to have growth inhibitory actions on prostate and colon cancer cells, suggesting that this compound may be of particular value in attenuating the adverse effects of obesity on neoplasia.

Integrative genomic analysis of phosphatidylinositol 3'-kinase family identifies PIK3R3 as a potential therapeutic target in epithelial ovarian cancer.

PURPOSE: The phosphatidylinositol 3'-kinase (PI3K) family plays a key regulatory role in various cancer-associated signal transduction pathways. Here, we investigated the genomic alterations and gene expression of most known PI3K family members in human epithelial ovarian cancer. EXPERIMENTAL DESIGN: The DNA copy number of PI3K family genes was screened by a high-resolution array comparative genomic hybridization in 89 human ovarian cancer specimens. The mRNA expression level of PI3K genes was analyzed by microarray retrieval approach, and further validated by real-time reverse transcription-PCR. The expression of p55gamma protein in ovarian cancer was analyzed on tissue arrays. Small interfering RNA was used to study the function of PIK3R3 in ovarian cancer. RESULTS: In ovarian cancer, 6 of 12 PI3K genes exhibited significant DNA copy number gains (>20%), including PIK3CA (23.6%), PIK3CB (27.0%), PIK3CG (25.8%), PIK3R2 (29.2%), PIK3R3 (21.3%), and PIK3C2B (40.4%). Among those, only PIK3R3 had significantly up-regulated mRNA expression level in ovarian cancer compared with normal ovary. Up-regulated PIK3R3 mRNA expression was also observed in liver, prostate, and breast cancers. The PIK3R3 mRNA expression level was significantly higher in ovarian cancer cell lines (n = 18) than in human ovarian surface epithelial cells (n = 6, P = 0.002). Overexpression of p55gamma protein in ovarian cancer was confirmed by tissue array analysis. In addition, we found that knockdown of PIK3R3 expression by small interfering RNA significantly increased the apoptosis in cultured ovarian cancer cell lines. CONCLUSION: We propose that PIK3R3 may serve as a potential therapeutic target in human ovarian cancer.

Modulation of human renal cell carcinoma 786-0 MMP-2 and MMP-9 activity by inhibitors and inducers in vitro.

A hallmark of renal cell carcinoma (RCC) invasion is its ability to degrade ECM by local production of gelatinase enzymes. Although many studies on RCC have demonstrated the importance of MMPs, very little information is currently known regarding the effect of inducers and inhibitors. We therefore investigated the effect of inducers and inhibitors on RCC 786-0 in vitro. Human RCC 786-0 (ATCC) was grown in RPMI medium supplemented with 10% FBS, penicillin, and streptomycin in 24-well tissue plates. At near confluence, the cells were washed with PBS; the serum-free medium was incubated with various inducers: phorbol ester (PMA), tumor necrosis factor alpha (TNF-alpha), interleukin 1-beta (IL-1beta) and lipopolysaccharides (LPS). Cells were also incubated with inhibitors: EGCG, doxycycline, and a nutrient mixture with and without PMA; retinoic acid, dexamethasone, H-7; actinomycin D, or cyclohexamide. After 24 h, the medium was removed and analyzed for MMP-2 and MMP-9 by gelatinase zymography. RCC 786-0 secreted two bands, a major band corresponding to MMP-2 and a faint band corresponding to MMP-9. PMA and TNF-alpha, with increased concentration, increased MMP-9 secretion, while IL-1beta and LPS did not significantly modify MMP-9 activity. MMP-2 secretion was not affected by any of the inducers. All the inhibitors tested without and with PMA showed a dose-dependent decrease in both MMP-2 and -9 expression. Further studies are in progress to confirm the role of MMP-9 on Matrigel invasion using PMA, cytokines, and LPS.