PC-SPES inhibits colon cancer growth in vitro and in vivo

PC-SPES is a mixture of eight herbs with antiproliferative activity in prostate cancer cell lines and antitumor effects in animal models of prostate cancer. In addition, evidence of clinical efficacy in advanced prostate cancer has been reported. PC-SPES has also been shown to have antitumor activity against several other cancer cell lines including breast and neuroepithelial cancer, melanoma, and leukemia cell lines. Because of these findings, we investigated the effects of PC-SPES in vitro in colon cancer cell lines SW480, SW620, and DLD-1 and in vivo in the Apc(min) mouse, a murine model for intestinal carcinogenesis. For the in vitro studies, colon cancer cell lines were exposed to an ethanolic extract of PC-SPES compared with a diluent control [ethanol < or = 0.3% (v/v)]. PC-SPES resulted in a marked suppression of cell proliferation in all colon cancer cells studied. PC-SPES (3 micro l/ml) caused a 95% inhibition of cell proliferation of the DLD-1 colon cancer cell line, and similar results were observed in the SW480 and SW620 colon cancer cell lines. Cell cycle analysis demonstrated a drastic (> or =60%) accumulation of cells in the G(2)-M phase with a concomitant decrease of cells in the G(0)-G(1) phase in all colon cancer cell lines studied after treatment with PC-SPES (1.5 micro l/ml for 48 h). Western blot analysis demonstrated a decrease in protein levels of beta-tubulin in the SW620 cell line exposed to PC-SPES. Terminal deoxynucleotidyl transferase-mediated nick end labeling analysis revealed an increase in apoptotic colon cancer cells incubated with PC-SPES. For the in vivo studies, female 4-5-week-old Apc(min) mice were randomized to two groups: a PC-SPES-treated group (n = 11) received 250 mg/kg/day (0.2 ml) PC-SPES via gastrointestinal gavage; and a control group (n = 10) received 0.2 ml of the vehicle solution (1.5% carboxymethylcellulose with 0.2% Tween 20) via gastrointestinal gavage. Both groups were treated five times a week for 10 weeks. After treatment, the gastrointestinal tract was dissected for polyp scoring by two observers blinded to treatment. The Apc(min) mice given PC-SPES had a 58% reduction in tumor number and a 56% decrease in tumor load. No effect on either food intake or body weight was observed in the treated versus sham groups. The present study is the first to report the potent activity of PC-SPES against colon cancer. Both cell cycle arrest and apoptosis occurred after treatment with PC-SPES. This suggests that the components of this herbal mixture, either independently or in combination, acted in colon cancer, resulting in a drastic effect on tumor initiation and tumor progression.     

Small interfering RNAs directed against beta-catenin inhibit the in vitro and in vivo growth of colon cancer cells.

The beta-catenin and APC genes are key components of the Wnt signaling pathway. Mutation of these genes results in increased levels of the beta-catenin protein, which is associated with enhanced cellular proliferation and the development of both colon polyps and colon cancer. Recently, a technique known as RNA interference has been successfully adapted to mammalian cells so that it is now possible to specifically decrease the expression of cellular genes after transfection of annealed small interfering 21-mer RNAs. In the current study, we used small interfering RNA (siRNA) directed against beta-catenin to determine the effects of decreasing the high constitutive levels of this protein in colon cancer cell lines with mutations in either beta-catenin or APC. Our studies demonstrate that siRNA directed against beta-catenin markedly decreased beta-catenin-dependent gene expression and inhibited cellular proliferation as reflected in the reduced growth of these colon cancer cells both in soft agar and in nude mice. These results indicate that siRNA can target specific factors whose expression is altered in malignancy and may have the potential as a therapeutic modality to treat human cancer.     

Small interfering RNAs targeting mutant K-ras inhibit human pancreatic carcinoma cells growth in vitro and in vivo

AIM: To investigate the effect of small interfering RNAs targeting mutant K-ras on the growth of pancreatic carcinoma cell lines in vitro and in vivo. MATERIALS AND METHODS: We cloned targeting sequence spanning codon 12 of mutant K-ras into the pSilencer-hygro plasmid, yielding two recombinant vectors with one base different. Both human pancreatic carcinoma cell lines were transfected by these two recombinant vectors. The transfected PC-7 cells were injected subcutaneously into nude mice to observe its tumorigenicity. RT-PCR and Western blot analysis were carried out to test the expression of K-ras in all of the transfected cell lines. Growth curves assay were performed to test the abilities of cells proliferation. Anti-K-ras therapy of PC-7 and Panc-1 in subcutaneous mice models were performed by intratumor injection of polyethylenimine/siRNAs complex. RESULTS: The expressions of K-ras in PC-7 cells and Panc-1 cells were significantly inhibited by corresponding small interfering RNAs. The expression of K-ras was particularly inactivated by siRNA without any base mismatch to its homologous mRNA, while this oncogene with central base mismatch could not be inhibited as effectively as that of the former. The growth of PC-7 cells and Panc-1 cells transfected by corresponding mutant K-ras targeted siRNAs were significantly suppressed when compared with controls (p<0.05). The transfected PC-7 cells lost tumorigenic ability. Four weeks treatment of Xenograft of pancreatic carcinoma (PC-7 and Panc-1) in nude mice with Polyethylenimine-encapsulated mutant K-ras targeted siRNAs (20 microg/mouse twice weekly) were effective in reducing tumor growth, when compared with controls (p<0.05). CONCLUSION: The central base may play a key role in the process of RNA interference. The mutant point and its vicinity of 19 nucleotides in K-ras may be the effective targeting sequence for RNA interference. Targeting mutant-k-ras therapy of pancreatic carcinoma may be a clinically applicable therapeutic modality.     

Marine compounds inhibit growth of multiple myeloma in vitro and in vivo

Purpose

The prognosis of patients with multiple myeloma (MM) is still dismal despite recent improvements achieved by introducing new therapeutic agents. However, there remains an urgent need for progress in myeloma drug development. We here show that novel marine-derived compounds can exert potent anti-myeloma activity.

Experimental Design

Nine marine-derived compounds were applied at low nM concentrations (0.1-100 nM) to MM cell lines (OPM-2, NCI-H929, U266, RPMI-8226), to primary human myeloma cells and to peripheral blood mononuclear cells. Apoptosis was determined by flow cytometry. In addition, eGFP-transgenic MM cell lines growing with mesenchymal cells from bone marrow were used to visualize tumors by fluorescence stereomicroscopy. Anti-myelomaactivities were studied in vitro in 3D spheroids and in vivo in myeloma xenografts on chicken embryos. Tumor size was analyzed by measuring GFP content with a GFP ELISA. Anti-angiogenic activities of compounds were tested in an in vivo gelatin sponge assay with conditioned media from primary bone marrow-derived endothelial cells.

Results

We identified a subset of marine compounds with strong anti-myeloma activity in vitro and in vivo. Moreover, some of the compounds inhibited myeloma-related angiogenesis in the in vivo gelatin sponge assay. They merit further drug development to improve treatment options for MM.     

Lentivirally engineered dendritic cells activate AFP-specific T cells which inhibit hepatocellular carcinoma growth in vitro and in vivo

α-fetoprotein (AFP), a tumor-associated antigen for hepatocellular carcinoma (HCC), is an established biomarker for HCC. In this study, we created a lentivirus expressing the AFP antigen and investigated the anti-tumor activity of AFP-specific CD8+ T cells, with and without CD4+ T cells, which were activated by either AFP peptide-pulsed or Lenti-AFP-engineered Dendritic cells (DCs) in vitro and in vivo. AFP-specific T cells could efficiently kill HepG2 HCC cells, and produced IL-2, IFN-γ, TNF-α, perforin and granzyme B, with minimal production of IL-10 (a negative regulator of T cell activation). Both strategies activated AFP-specific T cells, but the lentiviral strategy was superior by several measures. Data also support an impact of CD4+ T cells in supporting anti-tumor activity. In vivo studies in a xenograft HCC tumor model also showed that AFP-specific T cells could markedly suppress HCC tumor formation and morbidity in tumor-bearing nude mice, as well as regulate serum levels of related cytokines and anti-tumor molecules. In parallel with human in vitro T cell cultures, the in vivo model demonstrated superior anti-tumor effects and Th1-skewing with Lenti-AFP-DCs. This study supports the superiority of a full-length antigen lentivirus-based DCs vaccine strategy over peptides, and provides new insight into the design of DCs-based vaccines.     

The histone deacetylase inhibitor PXD101 synergises with 5-fluorouracil to inhibit colon cancer cell growth in vitro and in vivo

Abstract Purpose Histone deacetylase inhibitors (HDACi) inhibit the growth of cancer cells, and combinations of HDACi with established chemotherapeutics can lead to synergistic effects. We have investigated effects of PXD101 (HDACi in phase II clinical trials) in combination with 5-fluorouracil, on tumour cell proliferation and apoptosis both in vitro and in vivo. Experimental design HCT116 cells were studied using proliferation and clonogenic assays. Synergistic inhibition of proliferation and clonogenicity was determined by incubation with PXD101 and 5-fluorouracil, and analysis using CalcuSyn™ software. The effect of combining PXD101 and 5-fluorouracil on apoptosis was examined in vitro using PARP-cleavage and TUNEL. Finally, the effectiveness of combining PXD101 and 5-fluorouracil in vivo was tested using both HT-29 and HCT116 xenograft models. Results Synergistic inhibition of proliferation and clonogenicity was obtained when HCT116 cells were incubated with PXD101 and 5-fluorouracil. 5-fluorouracil combined with PXD101 also increased DNA fragmentation and PARP cleavage in HCT116 cells. Incubation with PXD101 down regulated thymidylate synthase expression in HCT116 cells. In vivo studies, using mouse HT29 and HCT116 xenograft models, showed improved reductions in tumour volume compared to single compound, when PXD101 and 5-fluorouracil were combined. Conclusions PXD101 and 5-fluorouracil synergistically combine in their anti-tumour effects against colon cancer cells in vitro and show enhanced activity when combined in vivo. Based on the results presented herein, a rationale for the use of PXD101 and 5-fluorouracil in combination in the clinic has been demonstrated.     

Inhibitors of mammalian target of rapamycin downregulate MYCN protein expression and inhibit neuroblastoma growth in vitro and in vivo

Mammalian target of rapamycin (mTOR) has been shown to play an important function in cell proliferation, metabolism and tumorigenesis, and proteins that regulate signaling through mTOR are frequently altered in human cancers. In this study we investigated the phosphorylation status of key proteins in the PI3K/AKT/mTOR pathway and the effects of the mTOR inhibitors rapamycin and CCI-779 on neuroblastoma tumorigenesis. Significant expression of activated AKT and mTOR were detected in all primary neuroblastoma tissue samples investigated, but not in non-malignant adrenal medullas. mTOR inhibitors showed antiproliferative effects on neuroblastoma cells in vitro. Neuroblastoma cell lines expressing high levels of MYCN were significantly more sensitive to mTOR inhibitors compared to cell lines expressing low MYCN levels. Established neuroblastoma tumors treated with mTOR inhibitors in vivo showed increased apoptosis, decreased proliferation and inhibition of angiogenesis. Importantly, mTOR inhibitors induced downregulation of vascular endothelial growth factor A (VEGF-A) secretion, cyclin D1 and MYCN protein expression in vitro and in vivo. Our data suggest that mTOR inhibitors have therapeutic efficacy on aggressive MYCN amplified neuroblastomas.     

Anti-HER-2 anti-CD3 bi-specific antibodies inhibit growth of HCT-116 colorectal carcinoma cells in vitro and in vivo

Objective: This study is conducted to evaluate the effects of anti-HER-2×anti-CD3 bi-specific antibodies(BsAb)on HER-2/neuover-expressing human colorectal carcinoma cells. Methods: Growth was assessed by MTT assaysafter exposure of HCT-116 cells to Herceptin, anti-CD3 and BsAb antibodies. Immunocytochemistry was appliedto test the HER-2 level of HCT-116. In a nude mouse model, HER-2×CD3 BsAb was combined with effectorcells (peripheral blood lymph cells from normal human being) for observations on in Vivo growth of tumors.Results: Compared with the control group, using effector cells combined with anti-CD3 McAb, Herceptin orHER2×CD3 BsAb, tumor cell growth in vitro and in vivo was significantly inhibited (P<0.05), most remarkablyin the HER2×CD3 BsAb case. The growth of xenografts with HER2×CD3 BsAb combined with effector cells wasalso significantly inhibited when compared with the anti-CD3 McAb or Herceptin groups (P<0.05). Conclusion:HER-2/neu might be a useful target for immunotherapy in colorectal carcinoma, anti-HER2×anti-CD3 BsAbexerting clear anti-tumor effects.     

Bisphosphonates inhibit the growth of mesothelioma cells in vitro and in vivo.

PURPOSE: Bisphosphonates (such as risedronate and zoledronate) are widely used inhibitors of bone resorption. Despite their in vitro antiproliferative effects in various cancer cells, bisphosphonates have not exhibited significant antitumor efficacy in animal models of visceral cancer, which may be due to their poor bioavailability. The diagnostic use of radioactive bisphosphonates has revealed the accumulation of bisphosphonates in mesothelioma, which prompted us to test the antitumor efficacy of bisphosphonates in this disease. EXPERIMENTAL DESIGN AND RESULTS: Treatment with either risedronate or zoledronate (2 x 10(-4) to 2 x 10(-6) mol/L) inhibited the growth of AB12 and AC29 mouse mesothelioma cells and induced the accumulation of unprenylated Rap1A in these cells. Both these in vitro effects were reversed by geranygeraniol, an end product of the mevalonate pathway that these bisphosphonates inhibit. Both bisphosphonates also induced the phosphorylation of the p38 mitogen-activated protein kinase in AB12 and AC29 cells. The inhibition of p38 augmented bisphosphonate-induced growth inhibition in these cells. Bisphosphonate-induced p38 phosphorylation was not reversible by geranylgeraniol. Risedronate (15 mg/kg) and zoledronate (0.5 mg/kg) inhibited the growth of s.c. tumors and increased the median survival of mice with i.p. mesothelioma tumors in vivo. Discussion: In conclusion, risedronate and zoledronate inhibit the mevalonate pathway and induce p38 activation in mesothelioma cells in vitro. The effects on the mevalonate pathway dominate because the net result is growth inhibition. Both bisphosphonates also inhibit mesothelioma tumor growth in vivo and prolong the survival of mesothelioma-bearing mice. These results support further study of bisphosphonates in the management of mesothelioma.     

Inhibition of human HT29 colon carcinoma growth in vitro and in vivo by swainsonine and human interferon-alpha 2

Swainsonine, a plant alkaloid and potent inhibitor of Asn-linked oligosaccharide processing, has previously been shown to inhibit organ colonization by metastatic murine tumor cells and to inhibit the growth of transformed fibroblasts in soft agar. In this report, we show that swainsonine has antiproliferative activity against human tumor cells growing in tissue culture and as tumor xenografts in nude mice. The antiproliferative activity of swainsonine was additive with that of human interferon-alpha 2 (HuIFN-alpha 2) in cultures of HT29 colon carcinoma, SN12 renal carcinoma, and A375 melanoma cells. In vivo, the growth rate of HT29m human colon carcinoma tumors in athymic nude mice was reduced by supplementing their drinking water with swainsonine (49%) or by administering HuIFN-alpha 2 systemically (53%); combining these treatments reduced tumor growth by 78%. Combining swainsonine and HuIFN-alpha 2 treatments enhanced the activity of the interferon-inducible enzyme 2',5'-oligoadenylate [2',5'-oligo(A)] synthetase in HT29m tumors compared to that observed in tumors from mice treated with interferon alone. In vitro, swainsonine enhanced interferon-dependent induction of 2',5'-oligo(A) synthetase activity in low-density cultures of HT29m cells. However, swainsonine alone did not stimulate 2',5'-oligo(A) synthetase activity in vivo or in vitro, indicating that the antiproliferative effect of swainsonine is independent of interferon production. The results suggest that in addition to the previously reported antimetastatic activity of swainsonine, the plant alkaloid has antiproliferative activity that is independent from, but additive with, that of interferon in vivo and in vitro.     

Amyloid beta protein precursor is involved in the growth of human colon carcinoma cell in vitro and in vivo

Amyloid beta protein precursor (APP) is a membrane-bound protein ubiquitously expressed in a variety of types of cells. However, its biological functions remain largely uncertain, particularly in non-neural cells and tumors. Our previous studies revealed that a secreted form of APP having a Kunitz-type inhibitor domain is a major serine proteinase inhibitor secreted by human colon carcinoma cells. In our study, we used an antisense RNA strategy to selectively inhibit the expression of APP in the human colon carcinoma cell line SW837. A vector capable of expressing an antisense mRNA complementary to 911 bases of the 5' end of APP mRNA was transfected into SW837 cells. After selection, 2 stably transfected antisense clones were obtained in which both the APP protein and mRNA were significantly suppressed. The proliferative potential and colony-forming efficiency of the antisense clones in vitro were markedly suppressed compared with the parent and mock-transfected clones. The addition of the conditioned medium of parent cells or purified secretory APP enabled these antisense effects to be overcome in vitro. The suppressed growth was also observed in vivo when the cells were injected subcutaneously into nude mice. Histologically, formation of tubular structures appeared to be suppressed in the antisense clones in vivo. These observations suggest potentially important roles of APP in cellular proliferation and differentiation of colon carcinoma cells.     

Valproic acid and interferon-alpha synergistically inhibit neuroblastoma cell growth in vitro and in vivo

Valproic acid (VPA) as a differentiation inducing anti-neoplastic substance is currently tested in solid tumour and leukaemia patients. Previously, we were able to show that the anti-cancer activity of VPA was synergistically increased by interferon-alpha (IFN-alpha) in Be(2)-C neuroblastoma (NB) cells. Now, we studied the effects of VPA in combination with IFN-alpha on two other NB cell lines. UKF-NB-2 and UKF-NB-3 cell growth was synergistically inhibited by VPA and IFN-alpha. Cell cycle investigations revealed massive accumulation of cells in G0/G1-phase after a combined treatment with VPA and IFN-alpha. The VPA-induced accumulation of acetylated histones in NB cell nuclei that indicates inhibition of histone deacetylases was not further enhanced by the combination treatment with IFN-alpha. Most strikingly, VPA plus IFN-alpha synergistically inhibited growth of UKF-NB-3 xenograft tumours in nude mice and induced complete cures in two out of six animals, while single treatment merely inhibited tumour growth. The results of this study together with our previous report strongly encourage the clinical evaluation of VPA and IFN-alpha for NB patients.     

Synthetic chenodeoxycholic acid derivatives inhibit glioblastoma multiform tumor growth in vitro and in vivo

We previously reported that the synthetic chenodeoxycholic acid (CDCA) derivatives showed apoptosis-inducing activity on various cancer cells in vitro. This study was undertaken to explore whether synthetic CDCA derivatives, HS-1199 and HS-1200, had an anticancer effect on malignant glioblastoma cells. We administered them in culture to U-118MG, U-87MG, T98G, and U-373MG cells. The tested glioblastoma cells showed several lines of apoptotic manifestations, such as activation of caspase-3, degradation of DFF, production of poly(ADP-ribose) polymerase cleavage, nuclear condensation, inhibition of proteasome activity, reduction of mitochondrial membrane potential and the release of cytochrome c to cytosol and translocation of AIF to nuclei. Between the two synthetic derivatives, HS-1200 showed a stronger apoptosis-inducing effect than HS-1199. In vivo efficacy of HS-1200 was tested in U87MG cells inoculated into non-obese diabetic and severe combined immunodeficient (NOD/SCID) mice. The HS-1200 treatment significantly inhibited the increase of tumor size in NOD/SCID mice and prolonged the life spans. This study supports the possibility of synthetic CDCA derivatives as a potential chemotherapeutic agent.     

Stable RNA interference of hexokinase II gene inhibits human colon cancer LoVo cell growth in vitro and in vivo

The purpose of this study is to investigate the effect of silencing hexokinase II (HK II) gene with RNA interference (RNAi) technique on colon cancer LoVo cell proliferation in vitro and in vivo. A short hairpin RNA (shRNA) eukaryotic expression vector against HK II gene was constructed, named as plasmid pGenesil-1-HK II, and transfected into LoVo cells. The expression of HK II gene was detected by RT-PCR and Western blot analysis respectively. Then, tumor colony formation was observed, and cell cycle was also assessed by flow cytometry and the contents of intracellular adenosine triphosphate (ATP) by high performance liquid chromatography (HPLC). Furthermore, LoVo cells were injected subcutaneously into nude mice. After a 4-week follow-up period, the sizes and weights of tumors were measured. Moreover, the expression of Ki67 protein was observed by immunohistochemical technique, and cell apoptosis by terminal deoxynucleotidyl transferase mediated nick end labeling (TUNEL). Consequently, the expression of HK II gene was efficiently blocked by RNAi. Downregulation of HK II gene expression significantly suppressed cloning efficiency and cell cycle of LoVo cell in vitro and tumor growth in vivo. Compared with untransfected LoVo cells, LoVo cells transfected with pGenesil-1-HK II plasmids showed significant decrease in the cellular ATP contents and Ki67 expression, and obvious increase in the apoptosis indexes. Our results suggest that HK II gene can act as a crucial therapeutic target for slowing colon cancer growth.     

MTA1 promotes nasopharyngeal carcinoma growth in vitro and in vivo

Background

The prognostic value of metastasis-associated gene 1 (MTA1) in nasopharyngeal carcinoma (NPC) has been suggested. However, there is still no direct evidence that MTA1 promotes NPC growth in vivo. In this study, we aimed to investigate the function of MTA1 in the regulation of NPC cell proliferation and tumorigenesis in vitro and in vivo.

Methods

Stable MTA1 knockdown or overexpression NPC cell lines were employed. The effects of MTA1 depletion or overexpression on cell proliferation, colony formation, cell cycle progression were examined by MTT, colony formation and flow cytometry assay. The effects of MTA1 depletion on tumor growth in vivo were examined in mouse xenograft model.

Results

MTA1 knockdown or overexpression drastically changed the proliferation, colony formation and cell cycle of NPC cells in vitro. MTA1 depletion significantly suppressed NPC tumorigenesis in vivo.

Conclusion

MTA1 promotes NPC cell proliferation via enhancing G1 to S phase transition, leading to increased tumor growth. Targeting MTA1 is a promising approach to reduce tumor burden of NPC.     

Amphiregulin anti-sense oligodeoxynucleotides inhibit growth and transformation of a human colon carcinoma cell line

Amphiregulin (AR) is a secreted heparin-binding growth factor that is structurally and functionally related to epidermal growth factor (EGF) and transforming growth factor a (TGFα). GEO cells are from a human colon cancer cell line that expresses high levels of AR protein and mRNA. To assess the role of AR in colon-cancer cell proliferation and transformation, 2 different anti-sense 20-mer phosphorothioate oligodeoxy-nucleotides (AR AS-1 and AR AS-2 S-oligos) complementary to the 5′ sequence of AR mRNA were synthesized. Both AR AS S-oligos were able to inhibit the anchorage-dependent growth (ADG) of GEO cells. The 2 AR AS S-oligos were equipotent when used in equimolar concentrations. In particular, a 40% growth inhibition was observed at a concentration of 10 μM, while a mis-sense S-oligo used as control had no effect on GEO cell growth. The AR AS-1 S-oligo used at the same concentration also inhibited by 40% the ³H-thymidine incorporation by DNA of GEO cells. The anchorage-independent growth (AIG) of GEO cells was even more significantly affected by AR AS S-oligo treatment. In fact, up to 80% inhibition of the AIG of GEO cells was observed when cells were treated with 10 μM of both AR AS S-oligos. Finally, the AR AS S-oligos were able to specifically inhibit AR protein expression in GEO cells, as assessed by immunocytochemistry. These data suggest that AR is involved in colon-cancer cell transformation, and that AR may represent a suitable target for gene therapy in human colon carcinomas. © 1995 Wiley-Liss, Inc.     

BMP signals inhibit proliferation and in vivo tumor growth of androgen-insensitive prostate carcinoma cells

Prostate cancer is one of the most common cancers in men. Several lines of evidence have suggested that bone morphogenetic protein (BMP) signals play important roles in the generation and progression of prostate cancers. In the present study, we show that BMP-7 inhibits the proliferation of androgen-insensitive PC-3 and DU-145 prostate cancer cells in a medium containing 1% fetal bovine serum, observed as decreased incorporation of [(3)H]thymidine and decreased cell number. Cell cycle analysis by flow cytometry showed an increased fraction of cells in the G1 phase and subsequent decrease in both S and G2/M phase after BMP-7 stimulation. BMP-7 caused an upregulation of the cyclin-dependent kinase inhibitor (CDKI) p21(CIP1/WAF1), and decreased the activity of Cdk2, leading to hypophosphorylation of Rb proteins. Furthermore, in order to evaluate the impact of BMP signals on prostate tumor growth, we generated the PC-3 cell lines expressing a constitutively active BMP type I receptor (constitutively active (c.a.) activin receptor-like kinase (ALK)-6) in a tetracycline (Tet)-regulated manner. Tet/doxycycline-regulated expression of c.a.ALK-6 resulted in the inhibition of in vitro cell proliferation and reduction of the size of tumors derived from the PC-3 cells subcutaneously injected into immune-deficient mice. Collectively, these findings suggest that BMP signals inhibit growth and proliferation of prostate tumor cells through induction of CDKI. Furthermore, this is the first report of a role for BMP signaling in reducing growth kinetics of androgen-insensitive prostate tumors.     

Soy-derived isoflavones inhibit the growth of adult T-cell leukemia cells in vitro and in vivo

Adult T-cell leukemia occurs in human T-lymphotropic virus type I-infected individuals and is endemic to the south-western area of Kyushu in Japan. In this communication, we examined the effect of soy isoflavones on the growth of adult T-cell leukemia cells in vitro and in vivo . In the in vitro study, daidzein and genistein but not glycitein significantly inhibited the proliferation of ED-40515 and Hut102 cells in a dose-dependent manner. Among the isoflavones studied, genistein had the highest growth-inhibitory effect; however, genistein did not exert an apparent growth-inhibitory effect on Jurkat and Molt-4 cells, which were non-adult T-cell leukemia cells. Genistein prevented the G₁/S or G₂/M transition at 3 and 10 or 30 µM, respectively. Genistein upregulated p21 protein expression together with p53 accumulation. In addition, treatment with 30 µM genistein strongly induced phosphorylation of checkpoint kinase (CHK) 2 and p53 at serines 15, 20 and 37. Caffeine, an inhibitor of ataxia-telangiectasia mutated protein kinase, alleviated the genistein-induced p53 and CHK2 phosphorylation, suggesting the involvement of DNA damage at 30 µM. However, marked phosphorylation of CHK2 and p53 could not be detected at 3 and 10 µM genistein. These data indicate that genistein has biphasic growth-inhibitory properties. The in vivo studies demonstrated that soy-derived isoflavones significantly inhibit ED-40515 cell growth and infiltration into various organs in non-obese diabetic severe combined-immunodeficiency common γ-chain knockout mice. Taken together, it is evident that soy isoflavones might serve as a promising compound for the treatment of adult T-cell leukemia. ( Cancer Sci 2007; 98: 1740–1746)     

IL-24基因对大鼠胶质瘤细胞生长状况的影响

目的　探讨IL 2 4基因对C6大鼠胶质瘤细胞生长状况的影响。方法　应用逆转录病毒载体 ,将IL 2 4基因导入C6细胞 ,经G4 18筛选后获得表达IL 2 4分子的阳性细胞克隆C6 /IL 2 4 ;用RT PCR方法检测目的基因表达 ;四甲基偶氮唑蓝 (MTT)法检测细胞体外增殖状况 ,流式细胞技术检测细胞的增殖活性 ,并制作荷瘤动物模型 ,观察C6 /IL 2 4和C6细胞的体内致瘤性。结果　RT PCR检测表明 ,外源IL 2 4基因于mRNA水平在C6 /IL 2 4细胞已获得稳定表达。C6 /IL 2 4细胞系的体外增殖性较亲代C6细胞明显下降 ,流式细胞术检测其细胞增殖指数 (PI)为 (2 9.71± 0 .89) %。 9只接种C6 /IL 2 4细胞的实验组大鼠中 ,6只颅内成瘤 ,肿瘤体积为 (14 .0 8± 9.81)mm3 ,明显小于接种C6细胞大鼠的肿瘤体积 (P <0 .0 5 )。结论　外源性IL 2 4基因可部分抑制胶质瘤细胞异常增殖的肿瘤特性。