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In this study, we reported millepachine (MIL), a novel chalcone compound for the first time isolated from Millettia pachycarpa Benth (Leguminosae), induced cell cycle arrest and apoptosis in human hepatocarcinoma cells in vitro and in vivo. In in vitro screening experiments, MIL showed strong antiproliferation activity in several human cancer cell lines, especially in HepG2 cells with an IC50 of 1.51 µM. Therefore, we chose HepG2 and SK-HEP-1 cells to study MIL's antitumor mechanism. Flow cytometry showed that MIL induced a G2/M arrest and apoptosis in a dose-dependent manner. Western blot demonstrated that MIL-induced G2/M arrest was correlated with the inhibition of cyclin-dependent kinase 1 activity, including a remarkable decrease in cell division cycle (cdc) 2 synthesis, the accumulation of phosphorylated-Thr14 and decrease of phosphorylation at Thr161 of cdc2. This effect was associated with the downregulation of cdc25C and upmodulation of checkpoint kinase 2 in response to DNA damage. MIL also activated caspase 9 and caspase 3, and significantly increased the ratio of Bax/Bcl-2 and stimulated the release of cytochrome c into cytosol, suggesting MIL induced apoptosis via mitochondrial apoptotic pathway. Associated with those effects, MIL also induced the generation of reactive oxygen species. In HepG2 tumor-bearing mice models, MIL remarkably and dose dependently inhibited tumor growth. Treatment of mice with MIL (20mg/kg intravenous [i.v.]) caused more than 65% tumor inhibition without cardiac damage compared with 47.57% tumor reduction by 5mg/kg i.v. doxorubicin with significant cardiac damage. These effects suggested that MIL and its easily modified structural derivative might be a potential lead compound for antitumor drug.

Inducing apoptosis is a promising therapeutic approach to overcome cancer. Here we described that a novel synthesized compound, 3-amino-N-(4-chlorobenzyl)-6-(3-methoxyphenyl)thieno[2,3-b]pyridine-2-carboxamide (SKLB703), exhibits antitumor activity via inducing apoptosis both invitro and invivo. Our results showed that SKLB703 inhibited the proliferation of a panel of human cancer cell lines, and human hepatocellular carcinoma cell line HepG2 was the most sensitive. The proliferation inhibitory effect of SKLB703 was associated with its apoptosis-inducing effect by activating caspase-3 and caspase-9 rather than caspase 8. Exposure of HepG2 to SKLB703 also resulted in Bax upregulation, Bcl-2 downregulation, cytochrome c release and mitochondrial transmembrane potential change in mitochondrial apoptotic pathway. Moreover, the decrease of phosphorylated p 44/42 mitogen-activated protein kinase and phosphorylated Akt was observed. SKLB703 suppressed the growth of established tumors in xenograft models in mice, whereas no toxicity was exhibited. TUNAL analysis showed that SKLB703 induced HepG2 tumor apoptosis. Taken together, the present study demonstrates that SKLB730 exhibits its antitumor activity through inducing apoptosis via mitochondrial apoptotic pathway. Its potential to be a candidate of anticancer agent is worth being further investigated.

PNAS-4, a novel pro-apoptotic gene activated during the early response to DNA damage, can inhibit proliferation via apoptosis when overexpressed in some tumor cells. The objectives of this study were to determine whether PNAS-4 could enhance apoptosis induced by cisplatin besides its induction of apoptosis, and to evaluate the usefulness of combined treatment with mouse PNAS-4 (mPNAS-4) gene therapy and low-dose cisplatin chemotherapy in the inhibition of tumor growth in colon carcinoma (CT26) and Lewis lung carcinoma (LL/2) murine models.In this study, the in vitro growth-inhibitory and pro-apoptotic effects of PNAS-4 and/or cisplatin on CT26, LL/2, and SKOV3 cancer cells were assessed by MTT assay, flow cytometric analysis, DNA fragmentation, and morphological analysis, respectively. The in vivo antitumor activity of combined treatment with mPNAS-4 gene therapy and low-dose cisplatin were evaluated in the inhibition of tumor growth in colon carcinoma (CT26) and Lewis lung carcinoma (LL/2) murine models. Tumor volume and survival time were observed. Induction of apoptosis was also assessed in tumor tissues.In vitro, PNAS-4 inhibited proliferation of colon carcinoma (CT26), Lewis lung carcinoma (LL/2) and human ovarian cancer (SKOV3) cell lines via apoptosis, and significantly enhanced the apoptosis of CT26, LL/2, and SKOV3 cells induced by cisplatin. In vivo systemic administration of expression plasmid encoding mPNAS-4 (pcDNA3.1-mPS) and cisplatin, significantly decreased tumor growth through increased tumor cell apoptosis compared to treatment with mPNAS-4 or cisplatin alone.Our data suggests that the combined treatment with mPNAS-4 plus cisplatin may augment the induction of apoptosis in tumor cells in vitro and in vivo, and that the augmented antitumor activity in vivo may result from the increased induction of apoptosis. The present study may provide a novel way to augment the antitumor efficacy of cytotoxic chemotherapy.

The matrix (M) protein of vesicular stomatitis virus (VSV) plays a key role in inducing cell apoptosis during infection. To investigate whether M protein-mediated apoptosis could be used in cancer therapy, its cDNA was amplified and cloned into eukaryotic expression vector pcDNA3.1(+). The recombinant plasmid or the control empty plasmid pcDNA3.1(+) was mixed with cationic liposome and introduced into various tumor cell lines in vitro, including lung cancer cell LLC, A549, colon cancer cell CT26 and fibrosarcoma cell MethA. Our data showed that the M protein induced remarkable apoptosis of cancer cells in vitro compared with controls. Fifty micrograms of plasmid in a complex with 250 microg cationic liposome was injected intratumorally into mice bearing LLC or MethA tumor model every 3 days for 6 times. It was found that the tumors treated with M protein plasmid grew much more slowly, and the survival of the mice was significantly prolonged compared with the mice treated with the control plasmid. In MethA fibrosarcoma, the tumors treated with M protein plasmid were even completely regressed, and the mice acquired longtime protection against the same tumor cell in rechallenge experiments. Both apoptotic cells and CD8(+) T cells were widely distributed in M protein plasmid-treated tumor tissue. Activated cytotoxic T lymphocytes (CTLs) were further detected by means of (51)Cr release assay in the spleen of the treated mice. These results showed that M protein of VSV can act as both apoptosis inducer and immune response initiator, which may account for its extraordinary antitumor effect and warrant its further development in cancer gene therapy.

Dendritic cells (DCs) are important cells in initiating an immune response. A generation of functional DCs has potential clinical use in treating cancer. However, the source of DCs and patient immunodeficiency with cancer have been hindrances in clinical therapy. We generated DCs from human umbilical cord blood mononuclear cells (UBMCs) with recombinant human granulocyte-macrophage colony stimulating factor, recombinant human interleukin-4, and recombinant human tumor necrosis factor-alpha. The mature DC-A549 lung cancer vaccine (AgL-DC) was prepared through loading A549 lysate, treating with lipopolysaccharide (LPS) and positive selecting with CD83 magnetic beads. AgL-DC can secrete interleukin (IL)-12 and IL-1. Further in vitro analysis showed that AgL-DC notably induced human UBMC lymphocyte proliferation (p0.01) by 3-(4,5-dimethylthiazol-z-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, increased the cytotoxic T-lymphocyte (CTL) activity of UBMC lymphocytes against A549 cells (p0.05, at effector cells:target cells ratios of 50:1 and 100:1) by lactate dehydrogenase (LDH) cytotoxic assay, and improved production of IL-6 and tumor necrosis factor-beta (p0.01, p0.05) by enzyme-linked immunosorbent assay. Subsequently, the reconstitute immunity model in severe combined immunodeficiencies (SCID) mice has been established using human UBMC transplantation, and similar trends to results of UBMC in vitro experiments have been shown in lymphocyte proliferation, CTL activity, and IL-6 and tumor necrosis factor-beta secretion levels in these models. AgL-DC also significantly (p0.01) increased the antitumor effect in vivo. The tumor infiltrating immunocytes were positively expressed human CD83 and CD3 molecules, and they were negatively expressed in tumor tissue treated with control. These results have demonstrated that umbilical cord DCs are a useful source of vaccine cells for augmenting CTL-mediated cytotoxicity and have potential usefulness in cellular therapy for human cancer in a new vaccination strategy.

Quercetin, a widely distributed bioflavonoid, inhibits the growth of various tumor cells. The present study was designed to investigate whether a novel quercetin derivative [phenylisocyanate of quercetin (PHICNQ)] exerts antitumor activity against K562 and CT26 tumor cell lines by inducing apoptosis, and to examine the possible mechanism in the phenomenon. The cell proliferation assay of K562 and CT26 tumor cells was determined by the trypan blue dye exclusion test. Apoptosis of PHICNQ-treated cells was determined by morphological analysis, agarose gel DNA electrophoresis and quantitated by flow cytometry after staining with propidium iodide. Cell cycle was evaluated by flow cytometry. The expression of heat shock protein 70 was checked by Western blot analysis. Our results showed that PHICNQ inhibited the proliferation of K562 and CT26 cells in a dose-dependent and time-dependent manner. PHICNQ was 308- and 73-fold more active on CT26 and K562 cells than quercetin, respectively. In addition to this cytostatic effect, treatment of K562 and CT26 tumor cells with PHICNQ induced apoptosis. PHICNQ treatment downregulated the expression of heat shock protein 70 more dramatically than quercetin treatment. These results suggest that PHICNQ is a more powerful antiproliferative derivative than quercetin, with cytostatic and apoptotic effects on K562 and CT26 tumor cells. PHICNQ may trigger apoptosis in tumor cells through inhibition of heat shock protein 70 synthesis and expression.

Purpose: Tie-2 is an endothelium-specific receptor tyrosine kinase known to play a key role in tumor angiogenesis. The present study explores the feasibility of immunotherapy of tumors by using a protein vaccine based on chicken Tie-2 as a model antigen to break the immune tolerance against Tie-2 in a cross-reaction between the xenogeneic homologous and self-Tie-2.Experimental Design and Results: In this study, a chicken homologous Tie-2 protein vaccine (chTie-2) and a corresponding mouse Tie-2 vaccine as a control were prepared and the antitumor effect of these vaccines was tested in two tumor models (murine B16F10 melanoma and murine H22 hepatoma). Immunotherapy with chTie-2 was found effective in two tumor models. Autoantibodies against mouse Tie-2 were detected in sera of mice immunized with chTie-2 through Western blot analysis and ELISA assay. Anti-Tie-2 antibody-producing B cells were detectable by ELISPOT. Histologic examination revealed that autoantibodies were deposited on the endothelial cells of tumor tissues. Purified immunoglobulins from chTie-2-immunized mice could induce the apoptosis of human umbilical vein endothelial cells in vitro. Importantly, adoptive transfer of purified immunoglobulins led to antitumor effect in vivo; apparently, angiogenesis was significantly inhibited in these tumors. Furthermore, the antitumor activity and production of autoantibodies could be abrogated by depletion of CD4+ T lymphocytes.Conclusions: Our findings may provide a vaccine strategy for cancer therapy and show the potential utilization of interference with Tie-2 pathway.

Hepatocellular carcinoma is one of the most common cancers in worldwide. We previously reported a novel thienopyridine derivative 3-amino-6-(3,4-dichlorophenyl) thieno[2,3-b]pyridine-2-carboxamide (SKLB70359) which possesses anticancer activity against hepatocellular carcinoma. In present study, we further investigated its anticancer activity and possible mechanism. The SKLB70359 treatment decreased the viability of a panel of hepatocellular carcinoma cell lines in a concentration- and time-dependent manner with IC(50) 0.4 ~ 2.5 μM. The mechanism study showed that SKLB70359 induced G0/G1 cell cycle arrest and then led to apoptotic cell death of HepG2 cell. The SKLB70359 induced G0/G1 cell cycle arrest was characterized by down-regulation of cyclin-dependent kinase 2 (CDK2), CDK4, CDK6 expression and up-regulation of p53, p21(WAF1). Activating of caspase-3 and caspase-9 was also observed. Meanwhile, proliferation inhibitory effect of SKLB70359 was associated with decreased level of phosphorylated p44/42 mitogen activated protein kinase (p44/42 MAPK) and phosphorylated retinoblastoma protein (Rb). Moreover, SKLB70359 exhibit less toxicity to non-cancer cells than tumor cells. In conclusion, the findings in this study suggested that SKLB70359 have potential anticancer efficacy via G0/G1 cell cycle arrest and apoptosis induction. Its potential to be a candidate of anticancer agent is worth being further investigated.

Antagonizing angiogenesis-related receptor tyrosine kinase is a promising therapeutic strategy in oncology. In present study, we designed and synthesized a novel vascular endothelial growth factor receptor (VEGFR) inhibitor N-methyl-4-(4-(3-(trifluoromethyl) benzamido) phenoxy) picolinamide SKLB610 that potently suppresses human tumor angiogenesis. SKLB610 inhibited angiogenesis-related tyrosine kinase VEGFR2, fibroblast growth factor receptor 2 (FGFR2) and platelet-derived growth factor receptor (PDGFR) at rate of 97%, 65% and 55%, respectively, at concentration of 10μM in biochemical kinase assays. In vitro, SKLB610 showed more selective inhibition of VEGF-stimulated human umbilical vein endothelial cells (HUVECs) proliferation, and this proliferation inhibitory effect was associated with decreased phosphorylation of VEGFR2 and p42/44 mitogen-activated protein kinase (p42/44 MAPK). Antiangiogenic evaluation showed that SKLB610 inhibited the HUVECs capillary-tube formation on Matrigel in vitro and the sub-intestinal vein formation of zebrafish in vivo. Moreover, SKLB610 inhibited a panel of human cancer cells proliferation in a concentration-dependent manner and human non-small cell lung cancer cell line A549 and human colorectal cancer cell line HCT116 were most sensitive to SKLB610 treatment. In vivo, chronic intraperitoneally administration of SKLB610 at dose of 50mg/kg/d resulted in significant inhibition in the growth of established human A549 and HCT116 tumor xenografts in nude mice without exhibit toxicity. Histological analysis showed significant reductions in intratumoral microvessel density (CD31 staining) of 43-55% relative to controls depending on the specific tumor xenografts. In conclusion, the present study demonstrated that SKLB610 exhibited its antitumor activity as a multi-targeted inhibitor with more potent inhibition of VEGFR2 activity. Its potential to be a candidate of anticancer agent is worth being further investigated.

Colon carcinoma is one of the common malignant tumors and has high morbidity and mortality in the world. Pigment epithelial-derived factor (PEDF) has been found to be the most potent natural inhibitor of angiogenesis and PEDF gene has been extensively used for the therapy of tumors, which suggests a potential approach to the therapy of colon carcinoma. However, the transfer of PEDF gene largely depends on the effective gene delivery systems. Poly (lactic-co-glycolic acid) nanoparticles (PLGANPs) have been extensively used for gene therapy due to its low-toxicity, biocompatibility and biodegradability, due to its potential to be an excellent carrier of the PEDF gene. We investigated the effect of PEDF gene loaded in PLGA nanoparticles (PEDF-PLGANPs) on the mouse colon carcinoma cells (CT26s) in vitro and in vivo. Blank PLGANPs (bPLGANPs) showed lower cytotoxicity than PEI to the CT26s. In vitro, PEDF-PLGANPs directly induced CT26 apoptosis and inhibit human umbilical vein endothelial cell (HUVEC) proliferation. In vivo, PEDF-PLGANPs inhibited CT26 tumors growth by inducing CT26 apoptosis, decreasing MVD and inhibiting angiogenesis. Our present study demonstrates the inhibitory effect of PEDF-PLGANPs on the growth of CT26s in vitro and in vivo for the first time. PLGANP-mediated PEDF gene could provide an innovative strategy for the therapy of colon carcinoma.

Basic fibroblast growth factor (bFGF) is a mitogen for endothelial cells, which participates in tumor angiogenesis. Active immunity against bFGF could be a promising approach for the biotherapy of cancer. Because bFGF is abundant in normal and malignant tissues, it is presumably difficult for normal bFGF to induce immunity due to self-tolerance. In addition, previous studies have shown that a complex consisting of a cationic liposome and a non-coding plasmid DNA can be used to stimulate innate immunity. This stimulation initiates a potent cytokine response, which can inhibit tumor growth. To investigate the effects of immunity against bFGF on murine colon carcinomas, we employed an N-, C-terminally truncated basic fibroblast growth factor (tbFGF, of human origin) as an antigen and a liposome-DNA complex as an adjuvant. After six immunizations, a robust bFGF-specific immune response was elicited. Subsequently, inhibition of tumor growth and a significant reduction in tumor vasculature were observed. The antitumor effect was confirmed by adoptive therapy of activated spleen cells from the immunized mice. In vitro, a CTL assay revealed that bFGF-specific cytotoxic T lymphocytes (CTL) resulted in the lysis of mouse microvascular endothelial cells (MS1) rather than that of the CT26 colorectal cancer cells. These results suggest that anti-angiogenesis treatment induced by a bFGF-specific CTLs against microvascular endothelial cells may be a useful method for cancer therapy.

To study the mechanisms of nongenomic effect of 17beta-estradiol on human spermatozoa.The intracellular calcium ([Ca2+]i) in the spermatozoa was measured by flow cytometry after the spermatozoa was treated with the inhibitors of trans-membrane signaling transduction pathways and impermeable 17beta-estradiol (E2-BSA). Western blot was used to detect the activation of the signal proteins after the spermatozoa was treated with 1 x 10(-6) mol/L E2-BSA and tamoxifen, an estrogen receptor inhibitor.Adenylyl cyclase (AC) inhibitor SQ22536, phospholipase C (PLC) inhibitor U73122 and protein tyrosine kinase (TPK) inhibitor Genistein all deterred the increase of [Ca2+]i caused by E2-BSA. E2-BSA also increased the PLC protein and PKC protein significantly. Tamoxifen, an antagonist of estrogen receptor, did not inhibit the activation of PLC caused by E2-BSA.The E2-BSA has an effect on human spermatozoa in a nongenomic pathway, possibly through the transmembrane signal transduction in relation to AC, PLC and TPK.

Purpose: Human neutrophil peptides (HNP1-3), small molecular antimicrobial peptides, are expressed within tumors and associated with tumor necrosis and inhibition of angiogenesis. Recent investigations have suggested that HNP1-3 are likely to be involved in the host immune responses to tumors.Experimental Design: We used recombinant pSec-HNP1, which expresses a secretable form of HNP1, to obtain expression of HNP1 in the tumor milieu in immunocompetent mice to explore the possible roles of HNP1 in tumor immunity. The antitumor effects were investigated in established CT26 colon cancer and 4T1 breast cancer models.Results: HNP1-mediated chemotactic and activating effects on immature dendritic cells were detected both in vitro and in vivo. Intratumoral expression of HNP1 resulted in not only significant tumor growth inhibition but also increased CTL infiltration within tumors. Adoptive transfer of splenocytes and a 51Cr release assay revealed specific cellular immune responses. Furthermore, increased antibodies were also found in sera from pSec-HNP1treated mice supporting specific humoral immune responses. Increased apoptosis and decreased angiogenesis were also shown in treated tumors.Conclusions: These findings indicate that HNP1 can exert multiple antitumor effects through different mechanisms; more importantly, HNP1 mediates host immune responses to tumors in situ through the recruitment and subsequent activation of immature dendritic cells and thus shows promising potential in cancer therapy. (Clin Cancer Res 2009;15(22):690111)

In our previous study, we developed a novel cationic liposome, which was modified with truncated human basic fibroblast growth factor (tbFGF) peptide. This tbFGF-mediated cationic liposome could deliver chemotherapeutic agents or gene specifically to FGFRs on tumors and obtained higher transfection efficiency than plain cationic liposomes. In order to investigate whether this novel cationic liposome could achieve a synergistic/combined anti-tumor effect as a co-delivery system, we simultaneously delivered doxorubicin (DOX) and the plasmid encoding the phosphorylation-defective mouse survivin threonine 34--alanine mutant (Msurvivin T34A plasmid) to the same cells through this cationic liposome. As a result, an enhanced antiproliferative activity in vitro has been achieved by delivering DOX and DNA simultaneously to the Lewis lung carcinoma cells (LLC) using this liposome. The concentration of DOX in the co-delivery system which caused 50% killing was nearly 3-fold lower than that of the free DOX. Furthermore, the co-delivery system suppressed tumor growth more efficiently than either DOX or the Msurvivin T34A plasmid alone in the Lewis lung carcinoma-bearing C57BL/6 mice. After 18 days of treatment with the co-delivery system, the average tumor volume in mice was decreased by 80%, which was higher than liposomal DOX (70%, P0.05) and Msurvivin T34A plasmid (41%, P0.01). The co-delivery system also caused 15 days delay of tumor growth, which was longer than the other treatment groups. In conclusion, this novel cationic liposome is an efficient vector to simultaneously deliver drugs and DNA to the same cells in vitro and in vivo.

Hepatitis B virus X protein (HBx) is a multi-functional regulatory protein that is known to be involved in viral proliferation, transcriptional activation and cell growth control. However, the actual role of HBx in cell growth control remains controversial. In this study, the impact of HBx on cell growth in vitro and in vivo was further investigated. HBx was able to inhibit the growth of hepatocellular carcinoma (HCC) cells and induce G2/M arrest in vitro. Moreover, unlike many other G2/M arrest mechanisms, HBx did not inhibit cyclin B1-CDK1 kinase activity, but it persistently activated the cyclin B1-CDK1 kinase. In vivo, HBx inhibited tumor cell growth and induced apoptosis as well as inhibited the growth of vascular endothelial cells. In conclusion, HBx induced G2/M arrest and apoptosis through sustained activation of cyclin B1-CDK1 kinase, and negatively regulated cell growth in vitro and in vivo.

PNAS-4, a novel pro-apoptotic gene activated during the early response to DNA damage, can inhibit proliferation via apoptosis when overexpressed in some tumor cells. Recent studies have indicated that honokiol can induce apoptosis, inhibit angiogenesis, and suppress tumor growth. In the present study, we investigated whether mouse PNAS-4 (mPNAS-4) could augment the apoptosis of tumor cells induced by honokiol in vitro, and whether the antiangiogenic activity of honokiol and induction of apoptosis by mPNAS-4 could work cooperatively to improve the antitumor efficacy in vivo. In vitro, mPNAS-4 inhibited proliferation of murine colorectal carcinoma CT26 and Lewis lung carcinoma LL2 cells through induction of apoptosis, and significantly augmented the apoptosis of CT26 and LL2 cells induced by honokiol. Compared with treatment with mPNAS-4 or honokiol alone, in vivo systemic administration of an expression plasmid encoding mPNAS-4 and low-dose honokiol significantly suppressed tumor growth through the enhanced induction of apoptosis and the augmented inhibition of angiogenesis. Our data suggest that the combined treatment with mPNAS-4 plus honokiol augments antitumor effects in vitro and in vivo, and that the improved antitumor activity in vivo may be associated with enhanced induction of apoptosis and augmented inhibition of angiogenesis. The present study may provide a novel and effective method for the treatment of cancer.

To investigate the anti-neoplastic effects of Valproic acid (VPA) on leukemic cells, especially drug-resistant lines, and to investigate whether modulation of GSH-redox status is involved in VPA-induced apoptosis.After the treatment of VPA at various concentrations for indicated times, cellular proliferation of the Jurkat, CEM, HL-60, K562, K562/AO2 cells were evaluated via MTT assay; and the activities of Caspase-3, Caspase-8 and Caspase-9 were quantitatively analyzed by colorimetric assay. The morphological change and cell cycle distribution were also examined on Jurkat (Dexamethasone-resistant) and K562/AO2 (Doxorubicin-resistant) cell lines. The levels of intracellular glutathione/glutathione disulfide (GSH/GSSG) and the activities of the typical antioxidant enzymes, i.e., glutathione reductase (GSH-Rd) and glutathione peroxidase (GSH-Px), were measured on cell lysates of Jurkat and K562/AO2 cell lines prior to and after VPA treatment. Apoptosis rates of Jurkat and K562/AO2 cells treated with VPA along or in combination with N-acety-l-cysteine (NAC), catalase (CAT) or DL-buthionine-(S,R)-sulfoximine (BSO) were determined by Annexin V/propidium iodide (PI) staining with flow cytometry analysis.At concentrations comparable with that achieved at clinical settings, VPA inhibited cell proliferation, activated Caspase-3, 8, and 9, and induced cell cycle arrest in Jurkat and K562/AO2. A rapid decrease in GSH-Rd and GSH-Px activities and GSH content in Jurkat and K562/AO2 were detected after VPA treatment. Co-administration of NAC or CAT attenuated VPA-induced apoptosis.VPA inhibit cell proliferation, induce cell cycle arrest and apoptosis in drug-resistant leukemic cells. Apoptosis correlates with down-regulation of intracellular GSH and disruption of intracellular GSH-redox balance, possibly through inhibition of glutathione reductase and glutathione peroxidase.

Chloroquine is an antimalarial drug that has been used in the treatment and prophylaxis of malaria since the 1950s. The present study was undertaken to examine the effects of chloroquine on Bcap-37 human breast cancer cells' growth, cell cycle modulation, apoptosis induction, and associated molecular alterations in vitro. The chloroquine treatment decreased the viability of Bcap-37 cells in a concentration- and time-dependent manner, which correlated with G(2)/M phase cell cycle arrest. The chloroquine-mediated cell cycle arrest was associated with a decrease in protein levels/activity of polo-like kinase 1 (Plk1), phosphorylated cell division cycle 25C (Cdc25C), phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2), phosphorylated Akt. The chloroquine-treated Bcap-37 cells exhibited a marked decrease in the level of mitochondrial transmembrane potential (DeltaPsim), which was accompanied by the activation of caspase-3 and cleaved poly(ADP-ribose) polymerase (PARP). Exposure of Bcap-37 cells to chloroquine also resulted in the induction of spindle abnormalities. In conclusion, the findings in this study suggested that chloroquine might have potential anticancer efficacy, which could be attributed, in part, to its proliferation inhibition and apoptosis induction of cancer cells through modulation of apoptosis and cell cycle-related proteins expressions, down-regulation of mitochondrial transmembrane potential (DeltaPsim), and induction of spindle abnormalities.

Genes involved in tumorigenesis may be targets for cancer immunotherapy. For many tumor types, molecular signatures do not yet exist. Methods that identify novel, tissue-specific tumor-related genes therefore have potentially important implications for developing cancer immunotherapy. Here, we used cross-reactive serological analysis of recombinant cDNA expression (CR-SEREX) to identify the novel testicular cancer-related gene, rat testicular antigenic protein 2 (RTAP2). We identified two RTAP2 splice variants (RTAP2a and RTAP2b) encoding 191 and 358 amino acid proteins, respectively. RTAP2a and RTAP2b proteins have identical N-termini but different C-terminal regions arising from alternative splicing of exon 4. Bioinformatics and reverse transcription-polymerase chain reaction (RT-PCR) revealed that the RTAP2a transcript was expressed selectively in adult testis and several tumor cell lines, while RTAP2b was ubiquitous. Our results suggest that RTAP2a may contribute to testicular development and tumorigenesis, and may be a candidate gene for cancer immunotherapy.

The purpose of this study was to investigate the effects of chloroquine diphosphate on the proliferation and apoptosis of human leukemic K562 cells, and to elucidate its possible mechanism of activity. The inhibitory effect of chloroquine diphosphate with different concentrations on K562 cell proliferation was detected by MTT method. Apoptosis was measured by flow cytometry (FCM); morphological analysis of apoptosis was performed after staining with propidium iodide (PI) under fluorescence microscope; cell apoptosis was assessed by the DNA ladder shown agarose gel electrophoresis. After treatment with chloroquine diphosphate, K562 cells were stained by Rhodamine 123 to detect changes in mitochondrial transmembrane potential (DeltaPsim) by FCM. The results showed that the cell viability decreased in dose-dependent manner, following chloroquine diphosphate treatment at different concentrations (1.5625, 3.125, 6.25, 12.5, 25, 50 and 100 micromol/L) for 24, 48 and 72 hours. By FCM analysis, the significant increases of sub-G(1) were observed. DNA ladder was detected and apoptotic nuclei were observed. DeltaPsim decreased in K562 cells after chloroquine diphosphate treatment. It is concluded that the chloroquine diphosphate can inhibit the proliferation of K562 cells and induce cell apoptosis, which may relate to down-regulation of mitochondrial transmembrane potential (DeltaPsim).

Honokiol, a well-tolerated natural product, can inhibit the proliferation of cancer cells. But its water insolubility hampers its systemic administration for therapy of cancer. As a drug delivery system, the pegylated liposome (PEGL) can increase the water solubility and targeting of the drug. Honokiol has been successfully encapsulated by PEGL in our laboratory. We wondered whether the combination treatment with pegylated liposomal honokiol (H-PEGL) and cisplatin (DDP) could improve the antitumor efficacy in ovarian carcinoma. H-PEGL could introduce apoptosis of SKOV3 cells in vitro, which was quantified by flow cytometric analysis, and the cellular morphologic changes were determined by propidium iodide staining. In a human ovarian carcinoma mouse model, combination treatment with H-PEGL (0.4 mg/day for 30 days; intraperitoneal) and DDP (5 mg/kg on days 7, 11, 15, 19; intraperitoneal) acted synergistically to inhibit tumor growth by 91.48% without notable toxicity, but H-PEGL and DDP alone only inhibit tumor growth by 66.83% and 52.5% as compared to the NaCl solution control, respectively. Assessment of microvessel density and apoptosis index by CD31 and terminal deoxynucleotidyl transferase–mediated nick end labeling immunohistochemistry respectively suggested that the antitumor activity of H-PEGL is mediated by angiogenesis inhibition and introduction of apoptosis. Our results showed us a splendid prospect of the clinical application of combination treatment on patients suffering from ovarian cancer with H-PEGL and DDP.

Cisplatin (CDDP), homoharringtonine (HHT), mitoxantrone (MIT) and hydroxycamptothecin (HCPT) are highly effective anti-tumor drugs. To evaluate their effects in the therapy of leukemia and establish a valuable method to estimate anti-tumor drugs, Annexin V/PI double parameter flow cytometry was used to detect the effects of these drug inducing apoptosis and death in Jurkat cell line. The results showed that MIT and HCTP-induced apoptosis effects on Jurkat cell line were obvious at 4 hours in early phase after adding drug (P0.05) and at 8 hours in late phase after adding drug (P0.05). HHT had obvious effect on inducing apoptosis of Jurkat cells, but no significant difference from low to high doses. The effect of CDDP on inducing apoptosis of Jurkat cell line was obviously weaker than that of HHT, MIT and HCPT, its weak effect on apoptosis of Jurkat cell line was found only at high concentration of drug for long time. Death effects on Jurkat cell line can not be observed in every experimental group. It is concluded that low dose of MIT can effectively induced apoptosis of Jurkat cell line. Annexin V/PI double parameter flow cytometry can be used as a reliable method for clinical screening anti-tumor drugs.

The objective of this study was to investigate antineoplastic effects of valproic acid (VPA) and trichostatin (TSA) on HL-60 and K562 cells in vitro, and the synergic effects of VPA or TSA in combination with ATRA. The inhibitory effects of VPA, TSA and ATRA in various concentrations and different combinations on proliferation of HL-60 and K562 cells were observed by cell growth curves, 50% inhibitory concentration (IC(50)), as well as inhibition of leukemia colony growth at different time points. The characteristics of cell differentiation or apoptosis were analyzed by cytochemical staining, differentiation antigen detection, cell cycle assay and A(NBT)/A(MMT) value determination. The results showed that HL-60 cell had a lower IC(50) of VPA and TSA compared with K562 cells. ATRA could significantly enhance the inhibition of VPA, TSA on clonegenicity of HL-60 cells and inhibition of VPA on clonegenicity of K562 cells. HL-60 cells treated with VPA displayed the phenotype of neutrophilic like cells, and showed the increases of NBT reduction rate and CD11b expression. No evidence for K562 differentiation was found. It is concluded that both VPA and TSA inhibit HL-60 cells growth in vitro. VPA induces differentiation of HL-60 cells to granulocyte. VPA and TSA have a moderate anti-proliferative effect on K562 cells. None of these agents induces K562 cell differentiation.

To explore the efficiency and mechanism of ovarian carcinoma gene therapy with the human fast-twitch skeletal muscle troponin I gene (Tnl-fast), Tnl-fast cDNA was transferred into human ovarian adenocarcinoma cell-line SK-OV-3. In vitro, the cell growth and cell cycle of Tnl-fast-, vector-, and mock-transfected cells were determined by MTT and flow cytometry assay, respectively. The conditioned media of Tnl-fast-, vector-, and mock-transfected SK-OV-3 cells were collected, and the cell proliferation inhibiting rates of human umbilical cord venous endothelial cells (HUVECs) by the three conditioned media were assayed. All the three cell lines were implanted into node mice, and the tumor growth, cell apoptosis, angiogenesis, and expression of Tnl-fast were observed or analyzed, respectively. In vitro, expression of Tnl-fast protein had no inhibiting effect on the growth of the dominant and stable transfectant cells, but endothelium, when compared with vector-transfected cells and nontransfected parental SK-OV-3 cells. Implantation of stable clone expressing Tnl-fast in the female BALB/c nude mice inhibits primary tumor growth by an average of 73%. The nude mice grafts expressing Tnl-fast exhibit a significant decrease of microvascular density, a higher rate of tumor cells apoptosis and a comparable proliferation rate as control. Our study, to our knowledge, shows the slowed down growth of the primary ovarian carcinoma, suggested that grafts were self-inhibitory by halting angiogenesis. Our data might also provide a novel useful strategy for cancer therapy by antiangiogenic gene therapy with a specific angiogenesis inhibitor Tnl-fast.

Endostatin is an important endogenous inhibitor of neovascularization, which has been widely used in anti-angiogenesis therapy for cancer. To fully explore the potential of endostatin, we evaluated the anti-tumor efficacy of the combination of recombinant human endostatin adenovirus and low-dose gemcitabine in nude mice. We injected recombinant human endostatin adenovirus intratumorally plus a low dose of gemcitabine i.p. routinely. The combination treatment produced no side-effects, and resulted in marked suppression in tumor formation and growth of established human lung carcinoma xenografts in nude mice, with decreased microvessel density and increased apoptosis percentage. Our data support the idea of synergistic anti-tumor properties of endostatin plus low-dose chemotherapy against human lung cancer in vivo.

To answer the question whether mitochondrial permeability transition (MPT) participates in blue light-induced damage to human retinal pigment epithelium (RPE) cells, this study was directed at assessing the effect of blue light on mitochondrial membrane potential (delta psi(m)) and cytochrome C (Cyt C) of cultured human RPE cells.Human RPE cells were exposed to blue light (wave length 470-490 nm); delta psi(m) was measured by rhodamine 123 staining and subsequent flow cytometry. Three groups were investigated: Group A (exposure to different intensity of blue light); group B (exposure to identical intensity for different duration); group C (exposure to identical intensity and duration, different prolongation of post-exposure culture). Cyt C activity was assayed by ELISA. Caspase-3 was detected by colorimetric assay. In these aspects, two groups were investigated: Group I [(2000+/-500) 1x for 6 h]; Group II [(2000+/-500) 1x for 12 h].When human RPE cells were exposed to blue light, the more pronounced decrease of delta psi(m) was consistent with the increase of light intensity in group A. Pronounced decrease of delta psi(m) was seen at 6 h and 12 h of exposure duration in group B. At 6 h prolongation of post-exposure culture in group C, the decrease of delta psi(m) was observed, lasting 48 h. The concentration of Cyt C was detected; no significant changes were found at 6 h and 12 h prolongation of post-exposure culture, but a significant increase was found at 24 h and 36 h post-exposure in the two groups. The increase was more significant in Group II than in Group I at 24 h post-exposure. The activity change of caspase-3 was not found in the two groups.Blue light exposure over threshold can induce damage to human RPE cells, probably by triggering the mitochondrial permeability transition, which results in the decrease of delta psi(m) and the release of cytochrome C.

Immune mediated suppression of hematopoiesis has been considered as one of the most important mechanisms leading to pancytopenia in myelodysplastic syndromes. This research was aimed at evaluating immune state of the MDS patients, analyzing the peripheral blood T cell subsets and CD3zeta chain expression and searching the possible reasons of hematopoietic disorders in 11 cases of MDS. Peripheral blood mononuclear cells were collected from 11 patients whose diagnosis was confirmed according to the new WHO diagnostic criteria. Flow cytometry was used for the counts of IFNgamma(+)CD4(+) cell (Th1), IL4(+)CD4(+) cell (Th2), IFNgamma(+)CD8(+) cell (Tc1), and IL4(+)CD8(+) cell (Tc2), and for the analysis of expression of CD3zeta chain in T cell subsets. The results showed that CD8(+) cells increased significantly in MDS patients; there was no significant difference between Th1/Th2, Tc1/Tc2 ratios of T cell subsets and normal control; CD3zeta chain, the functional protein in the signal transduction pathway of T cell, was over expressed in the CD8(+) cell. In conclusion, research indicates that abnormal changes of T cell subgroups exist in peripheral blood of MDS patients. Enhancement of CD8(+) cells and over-expression of CD3zeta chain are important features, which suggest that CD8(+) cells play the most critical role in the pathologic process as compared with other T cell subsets. The over active immunity mediated by T cell subset may be one of the major mechanisms resulting in cytopenia in MDS.

To culture dendritic cells (DCs) from human acute myeloid leukemia (AML) cells, and to observe the cytotoxic effect of the T lymphocytes that are activated by DCs pulsed with leukemic antigen peptides (LAP) or LAP-heat shock protein 90 (HSP90) on autologous AML cells.Mononuclear cells (MNC) were isolated from peripheral blood (PB) and bone marrow (BM) of patients with AML by density gradient centrifugation; DCs were induced from MNC of PB in a special culture system including recombinant human granulocyte-monocyte colony stimulating factor (rhGM-CSF), interleukin-4 (rhIL-4) and tumor necrosis factor-alpha (TNF-alpha) for 7-14 days. These DCs were identified by morphology and immunophenotype studies; LAP were obtained by repeatedly freezing and thawing AML cells respectively. DCs were pulsed with LAP and LAP-HSP90 compounds respectively. The cytotoxity of T lymphocytes activated by antigen pulsed DCs on autologous AML cells was measured in vitro by the lactate dehydrogenase-release assay.After 7-14 days' culture, (6-11) x 10(4) DCs were obtained from 1 x 10(6) MNC of PB in 3 AML cases. The cytotoxity rates of T lymphocytes, from 3 AML cases, activated by DCs pulsed with LAP and LAP-HSP90 compounds were (35.33+/-9.04)% and (62.07+/-8.29)% respectively.Effective cytotoxity of T lymphocytes to the autologous leukemia cells can be induced by DCs pulsed with LAP and LAP-HSP90 compounds respectively, but the effectiveness induced by the latter is more powerful than that induced by the former.

Angiogenesis is critical to the growth and metastasis of solid tumors, and acquired drug resistance is one of the major hindrances to chemotherapy. Thus, we sought a rational strategy using the combination of antiangiogenic biotherapy and chemotherapy for cancer therapy. We explored the efficacy of a strategy combining low-dose cisplatin and a recombinant xenogeneic endoglin as a protein vaccine, which we previously demonstrated to have effective antiangiogenic effects in several mouse models. We found that both low-dosage cisplatin and xenogeneic endoglin vaccine individually resulted in effective suppression of tumor growth in 2 tumor models via inhibition of tumor angiogenesis. Remarkably, the combination therapy resulted in not only significant antiangiogenic effects but also additional promotion of tumor cell apoptosis and inhibition of tumor cell proliferation, without any ensuing increase in host toxicity during the course of treatment, which lasted for 6 months. In addition, the combination demonstrated a synergistic relationship, which was shown in all of the synergistic indexes, i.e., tumor volume, angiogenesis, apoptosis and proliferation. Both antibodies and antibody-producing B cells against mouse self-endoglin were observed in all mice immunized by the xenogeneic endoglin vaccine (alone and combination), which suggested that low-dose cisplatin did not suppress the host immune response but potentiated the antitumor activity of the xenogeneic endoglin vaccine. These observations may provide the basis for an effective alternative strategy for cancer therapy in the near future.

Vesicular stomatitis virus (VSV) has been shown to replicate rapidly in vitro and kill selectively a variety of tumor cell lines. The present study was designed to determine whether gemcitabine potentiates the antitumor activity of VSV in vitro and in vivo. A549 human lung adenocarcinoma cells and LLC Lewis lung carcinoma cells were treated with VSV (0.1-10 plaque-forming units per cell) plus gemcitabine (20 nM to 20 microM). Mice bearing A549 or LLC were treated with VSV (5 x 10(4) to 1 x 10(8) plaque-forming units) daily for 5 days plus gemcitabine (5-125 mg/kg/day) once every 3 days for 4 times. Induction of apoptosis and effects on growth inhibition were assessed. The lung cancer cells treated with VSV plus gemcitabine displayed the apparently increased apoptotic cells compared with treatment with VSV or gemcitabine alone. The combined treatment with VSV plus gemcitabine induced the apparent antitumor activity with complete regression of the established lung cancer in both A549 and LLC lung cancer models and augmented the induction of apoptosis in lung cancer cells in vivo as well. This study suggests that the combined treatment with VSV plus gemcitabine may augment the induction of apoptosis in lung cancer cells in vitro and in vivo, and that the augmented antitumor activity in vivo may result from the increased induction of apoptosis in lung cancer cells. The present findings may be of importance to the further exploration of the potential application of this combined approach in the treatment of lung cancer.

The breaking of immune tolerance against self epidermal growth factor receptor (EGFr) should be a useful approach for the treatment of receptor-positive tumors with active immunization. To test this concept, we constructed a plasmid DNA encoding extracellular domain of xenogeneic (human) EGFr (hEe-p) or corresponding control mouse EGFr (mEe-p) and empty vector (c-p). Mice immunized with hEe-p showed both protective and therapeutic antitumor activity against EGFr-positive tumor. Sera isolated from the hEe-p-immunized mice exhibited positive staining for EGFr-positive tumor cells in flow cytometric analysis and recognized a single 170-kDa band in Western blot analysis. Ig subclasses responded to rEGFr proteins were elevated in IgG1, Ig2a, and Ig2b. There was the deposition of IgG on the tumor cells. Adoptive transfer of the purified Igs showed the antitumor activity. The increased killing activity of CTL against EGFr-positive tumor cells could be blocked by anti-CD8 or anti-MHC class I mAb. In vivo depletion of CD4+ T lymphocytes could completely abrogate the antitumor activity, whereas the depletion of CD8+ cells showed partial abrogation. The adoptive transfer of CD4-depleted (CD8+) or CD8-depleted (CD4+) T lymphocytes isolated from mice immunized with hEe-p vaccine showed the antitumor activity. In addition, the increase in level of both IFN-γ and IL-4 was found. Taken together, these findings may provide a new vaccine strategy for the treatment of EGFr-positive tumors through the induction of the autoimmune response against EGFr in a cross-reaction between the xenogeneic homologous and self EGFr.

This study aims to develop self-assembled poly(ethylene glycol)-poly(epsilon-caprolactone)-poly(ethylene glycol) (PEG-PCL-PEG, PECE) micelles to encapsulate hydrophobic honokiol (HK) in order to overcome its poor water solubility and to meet the requirement of intravenous administration. Honokiol loaded micelles (HK-micelles) were prepared by self-assembly of PECE copolymer in aqueous solution, triggered by its amphiphilic characteristic assisted by ultrasonication without any organic solvents, surfactants and vigorous stirring. The particle size of the prepared HK-micelles measured by Malvern laser particle size analyzer were 58 nm, which is small enough to be a candidate for an intravenous drug delivery system. Furthermore, the HK-micelles could be lyophilized into powder without any adjuvant, and the re-dissolved HK-micelles are stable and homogeneous with particle size about 61 nm. Furthermore, the in vitro release profile showed a significant difference between the rapid release of free HK and the much slower and sustained release of HK-micelles. Moreover, the cytotoxicity results of blank micelles and HK-micelles showed that the PECE micelle was a safe carrier and the encapsulated HK retained its potent antitumor effect. In short, the HK-micelles were successfully prepared by an improved method and might be promising carriers for intravenous delivery of HK in cancer chemotherapy, being effective, stable, safe (organic solvent and surfactant free), and easy to produce and scale up.