胰岛素样生长因子-Ⅰ上调表皮生长因子对HCE16/3细胞的作用

目的了解胰岛素样生长因子－Ｉ（ＩＧＦ－Ｉ）对ＨＰＶ１６型ＤＮＡ－永生化的人宫颈上皮细胞（ＨＣＥ１６／３细胞）的生长和病毒基因表达的调节。方法使用流式细胞术、软琼脂糖试验和ＲＴ－ＰＣＲ分析了ＩＧＦ－Ｉ和表皮生长因子（ＥＧＦ）对ＨＣＥ１６／３细胞的生长和病毒早期基因表达的调节。结果在缺乏血清的培养条件下,ＩＧＦ－Ｉ对ＨＣＥ１６／３细胞的生长几乎没有调节作用。但ＥＧＦ对永生化上皮细胞有生长刺激作用,这种刺激作用可被ＩＧＦ－Ｉ增强。ＥＧＦ合并使用ＩＧＦ－Ｉ可诱导ＨＣＥ１６／３细胞停泊不依赖性生长。ＲＴ－ＰＣＲ显示ＩＧＦ－Ｉ并不明显改变ＨＣＥ１６／３细胞病毒早期基因的表达。结论ＩＧＦ－Ｉ是ＨＣＥ１６／３细胞生长的弱调节剂,但它可以增强ＥＧＦ对ＨＣＥ１６／３细胞生长的刺激作用     

Mechanism of growth inhibitory effects of cyclooxygenase-2 inhibitor-NS398 on cancer cells

Cyclooxygenase (COX)-2 appears to play an important role in gastrointestinal carcinogenesis, and COX-2 overexpression has been demonstrated both in esophageal adenocarcinomas and lymph nodes metastasis. The aim of our study was to investigate the mechanism of growth inhibitory effect of selective inhibition of COX-2 by NS-398 on human cancer cells. The esophageal cancer cell lines (EC9706) that express COX-2 permanently and hepatocellular carcinoma cell lines (SMMC7721) while no expression of COX-2 were studied. Two kinds of cell lines were treated with various concentrations of NS-398 (selective for COX-2 inhibition) at 0.01-0.1 mM for 24 h, 48 h and 72 h. Antiproliferation effect was measured by 3H-TdR incorporation. The cell apoptosis were determined by flow cytometry (FCM) and DNA fragmentation analysis. Survivin was detected by immunocytochemical technique. The growth inhibition could be induced by NS398 in a dose- and time-dependent manner in two kinds of cell lines. FCM analysis revealed a high sub-G1 cell peak in EC9706 group. Agarose electrophroesis showed marked apoptosis ladder pattern, but no apoptosis by NS-398 in SMMC7721. The difference of apoptosis percentage in EC9706 and SMMC7721 was (45.23 +/- 1.08)% and (3.05 +/- 0.15)% (p < 0.001). After 24 h incubation with NS-398 at concentration of 0.1 dmM, the expression of survivin was markedly reduced in EC9706, but not in SMMC7721. We conclude that the administration of a selective inhibitor of COX-2 significantly decreases cell growth in cancer cell lines by different mechanism. NS-398 could inhibit cell proliferation in cancer cells whether or no COX-2 expression. Nevertheless, apoptosis in the cancer cells expressing COX-2 protein increase more than those lacking COX-2.     

Insulin-like growth factor-I receptor/human epidermal growth factor receptor 2 heterodimerization contributes to trastuzumab resistance of breast cancer cells

The majority of breast cancer patients who achieve an initial therapeutic response to the human epidermal growth factor receptor 2 (HER-2)-targeted antibody trastuzumab will show disease progression within 1 year. We previously reported the characterization of SKBR3-derived trastuzumab-resistant pools. In the current study, we show that HER-2 interacts with insulin-like growth factor-I receptor (IGF-IR) uniquely in these resistant cells and not in the parental trastuzumab-sensitive cells. The occurrence of cross talk between IGF-IR and HER-2 exclusively in resistant cells is evidenced by the IGF-I stimulation resulting in increased phosphorylation of HER-2 in resistant cells, but not in parental cells, and by the inhibition of IGF-IR tyrosine kinase activity leading to decreased HER-2 phosphorylation only in resistant cells. In addition, inhibition of IGF-IR tyrosine kinase activity by I-OMe-AG538 increased sensitivity of resistant cells to trastuzumab. HER-2/IGF-IR interaction was disrupted on exposure of resistant cells to the anti-IGF-IR antibody alpha-IR3 and, to a lesser extent, when exposed to the anti-HER-2 antibody pertuzumab. Heterodimer disruption by alpha-IR3 dramatically restored sensitivity to trastuzumab and resistant cells showed a slightly increased sensitivity to pertuzumab versus parental cells. Neither alpha-IR3 nor pertuzumab decreased HER-2 phosphorylation, suggesting that additional sources of phosphorylation other than IGF-IR exist when HER-2 and IGF-IR are not physically bound. Our data support a unique interaction between HER-2 and IGF-IR in trastuzumab-resistant cells such that cross talk occurs between IGF-IR and HER-2. These data suggest that the IGF-IR/HER-2 heterodimer contributes to trastuzumab resistance and justify the need for further studies examining this complex as a potential therapeutic target in breast cancers that have progressed while on trastuzumab.     

Insulin-like growth factor-I promotes migration in human androgen-independent prostate cancer cells via the alphavbeta3 integrin and PI3-K/Akt signaling

In its phase of androgen-independence, prostate carcinoma is characterized by a high proliferation rate and by a strong ability to give rise to metastases. IGF-I has been shown to exert a potent mitogenic action on prostate cancer. We investigated whether IGF-I might also affect the motility of prostate cancer cells and defined the mechanism of action. We found that IGF-I promotes the migratory capacity of androgen-independent prostate cancer cells through the activation of its specific receptor, IGF-IR. This effect was accompanied by a change in cell morphology (as revealed by scanning electron microscopy), and by a rearrangement of the actin cytoskeleton. The treatment of cells with the PI3-K inhibitor, LY294002, counteracted the pro-migratory activity of IGF-I. Experiments were then performed to clarify whether the integrin, alphavbeta3, could be involved in the action of IGF-I. We demonstrated that: a) the IGF-I-induced migration of cells is completely antagonized by an antibody specifically blocking the function of alphavbeta3; b) IGF-I increases alphavbeta3 immunofluorescence at the level of cell membranes, and this effect is counteracted by LY294002; and c) IGF-I increases alphavbeta3 protein levels. Our results demonstrate that IGF-I promotes the motility of androgen-independent prostate cancer cells by modulating alphavbeta3 integrin activation/expression; these effects are mediated by the PI3-K/Akt signaling pathway. This study: a) supports a crucial role for IGF-I in the progression of the pathology towards the highly metastatic phase; and b) provides an additional rationale basis for the development of therapeutic strategies directed at the IGF-I/IGF-IR system in the treatment of androgen-independent prostate cancer.     

Selective cyclooxygenase-2 inhibitors inhibit growth and induce apoptosis of bladder cancer

Selective COX-2 inhibitors such as celecoxib and NS-398 are being evaluated as chemopreventive and therapeutic agents for bladder and other cancers. We investigated the effects of these nonsteroidal anti-inflammatory agents on a panel of bladder cancer cell lines, and assessed their effects on anchorage-dependent and -independent growth, cell cycle, apoptosis and morphology. The human bladder cancer cell lines UM-UC-1, -3, and -6 were assayed for COX-2 expression by Western analysis using a monoclonal antibody to COX-2. UM-UC-1, -3, and -6 cells were grown in the presence of increasing concentrations of NS-398 and celecoxib, and cell growth was quantitated over 7 days by crystal violet elution. The cell lines were treated with NS-398 and celecoxib for 48 h and analyzed by flow cytometry with propidium iodide staining and Br-dUTP staining for apoptosis. Anchorage-independent growth was assessed using an agarose growth assay. Western analysis demonstrated that COX-2 expression in UM-UC-1, -6, and -3 was high, low, and undetectable, respectively. NS-398 and celecoxib produced dose-dependent growth inhibition of UM-UC-1 and -6. Both NS-398 and celecoxib also inhibited anchorage-dependent and -independent growth of UM-UC-3 in a dose-dependent fashion, despite the low basal expression of COX-2 in this cell line. Cell cycle analyses of UM-UC-1 and -6 revealed a 50% reduction in S-phase in the presence of 100 microM NS-398 whereas a smaller reduction in S-phase was noted in UM-UC-3 cells. Furthermore, treatment with 100 microM celecoxib resulted in significant apoptosis in all three cell lines, which was associated with downregulation of Bcl-2. COX-2 selective inhibitors NS-398 and celecoxib produced dose-dependent growth inhibition of bladder cancer cells associated with a significant reduction in S-phase. Induction of apoptosis in all three cell lines by celecoxib was associated with downregulation of Bcl-2. These changes occur independently of COX-2 expression levels suggesting the presence of a COX-2 independent pathway.     

Insulin-like growth factor-I receptor antagonism results in increased cytotoxicity of breast cancer cells to doxorubicin and taxol

Therapeutic strategies for patients with advanced-stage adenocarcinoma of the breast frequently include the use of cytotoxic chemotherapy. Insulin-like growth factor I (IGF-I) receptor, a key factor in cell-cycle regulation, is frequently overexpressed in high-grade breast cancers. IGF-I receptor overexpression in these tumors may provide a target for novel molecular therapy against this disease. Early passage samples of estrogen-responsive (ER+) MCF 7 and estrogen receptor-negative (ER-) MDA-231 cells were cultured in semi-confluent conditions. Dose-titrations were performed for doxorubicin and taxol with receptor modulation using IGF-I or a competitive receptor inhibitor, alphaIR3. The addition of 100 ng/ml IGF-I resulted in a >2-fold mitogenic response in both ER+ and ER- cells. Receptor activation prior to the treatment with cytotoxic chemotherapeutic agents altered the pattern of response with a 26.3% increase in IC50. Doxorubicin and taxol both produced dose-related toxicity with IC50 of 0.05 microg/ml and 0.00 microg/ml respectively. The addition of alphaIR3 resulted in increased cytotoxicity in IGF-I stimulated cells compared with the use of doxorubicin or taxol alone. These results suggest that IGF-I receptor modulation alters the response to cytotoxic chemotherapeutic agents in breast cancer cells.     

Insulin-like growth factor-I (IGF-I) and IGF binding protein-3 as predictors of advanced-stage prostate cancer

BACKGROUND: Plasma levels of insulin-like growth factor-I (IGF-I) have been associated with the risk of prostate cancer. However, the association of IGF-I with specific tumor stage and grade at diagnosis, which correlate with risk of recurrence and mortality, has not been studied rigorously. To determine whether plasma levels of IGF-I and its main circulating binding protein, IGF binding protein-3 (IGFBP-3), predict more aggressive forms of prostate cancer, we investigated the association between plasma levels of each and specific stages and grades of prostate cancer. METHODS: We examined 530 case patients and 534 control subjects in a nested case-control study in the prospective Physicians' Health Study. Patients with prostate cancer diagnosed from 1982 through 1995 were matched to control subjects by age and smoking status. IGF-I and IGFBP-3 were measured in prospectively collected plasma samples. Conditional logistic regression models were used to estimate the relative risks (RRs) for prostate cancer associated with IGF-I and IGFBP-3, stratified on grade (Gleason score > or = 7 versus <7) and stage (early = stage A or B prostate cancer versus advanced = stage C or D prostate cancer). All statistical tests were two-sided. RESULTS: Plasma levels of IGF-I and IGFBP-3 were predictors of advanced-stage prostate cancer (RR = 5.1, 95% confidence interval [CI] = 2.0 to 13.2 for highest versus lowest quartiles of IGF-I; RR = 0.2, 95% CI = 0.1 to 0.6 for highest versus lowest quartiles of IGFBP-3) but not of early-stage prostate cancer. Neither was differentially associated with Gleason score. Men with high IGF-I levels and low IGFBP-3 levels had an RR for advanced-stage prostate cancer of 9.5 (95% CI = 1.9 to 48.4) compared with men with low levels of both. Combining IGF-I and IGFPB-3 measurements with a standard prostate-specific antigen (PSA) measurement for prostate cancer screening increased the specificity (from 91% to 93%) but decreased sensitivity (from 40% to 36%) compared with measurement of PSA alone. CONCLUSIONS: Circulating levels of IGF-I and IGFBP-3 may predict the risk of developing advanced-stage prostate cancer, but their utility for screening patients with incident prostate cancer may be limited.     

PUMA基因对胰腺癌细胞BxPC-3的促凋亡作用及其可能机制

目的：研究P53正向凋亡调节因子基因(P53 upregulate modulator of apoptosis,PUMA)对胰腺癌细胞株BxPC3凋亡的影响及其可能的作用机制。方法：以100 MOI的携PUMA基因重组腺病毒（AdPUMA）感染BxPC3细胞0～96 h,流式细胞术检测BxPC3细胞凋亡率,Western blotting检测BxPC3细胞中PUMA、Bcl2、Bax、Cytochrome C和Caspase3蛋白的表达,Western blotting检测BxPC3细胞中细胞质和线粒体内Bax的表达及Bax寡聚体。结果：随着AdPUMA感染时间的延长,BxPC3细胞凋亡率逐渐增加,48 h时最高。AdPUMA感染促进BxPC3细胞中PUMA、Cytochrome C和Caspase3 蛋白的表达,抑制BxPC3细胞中Bcl2蛋白的表达。AdPUMA感染后BxPC3细胞的凋亡率与BxPC3细胞中PUMA蛋白的表达具有明显的相关性。AdPUMA感染不影响BxPC3细胞中Bax蛋白的总表达量,但细胞质中的Bax几乎完全消失,而线粒体中的Bax表达明显增加;AdPUMA感染诱导BxPC3细胞中Bax蛋白的寡聚化。结论：PUMA基因通过线粒体途径促进胰腺癌细胞凋亡。     

Frondoside A enhances the antiproliferative effects of gemcitabine in pancreatic cancer

Pancreatic cancer has a very poor prognosis. While gemcitabine is the mainstay of therapy and improves quality of life, it has little impact on survival. More effective treatments are desperately needed for this disease. Frondoside A is a triterpenoid glycoside isolated from the Atlantic sea cucumber, Cucumaria frondosa. Frondoside A potently inhibits pancreatic cancer cell growth and induces apoptosis in vitro and in vivo. The aim of the present study was to investigate whether frondoside A could enhance the anti-cancer effects of gemcitabine.Effects of frondoside A and gemcitabine alone and in combination on proliferation were investigated in two human pancreatic cancer cell lines, AsPC-1 and S2013. To investigate possible synergistic effects, combinations of low concentrations of the two drugs were used for a 72 h treatment period in vitro. Growth inhibition was significantly greater with the drug combinations than their additive effects.Combinations of frondoside A and gemcitabine were tested in vivo using the athymic mouse model. Xenografts of AsPC-1 and S2013 cells were allowed to form tumours prior to treatment with the drugs alone or in combination for 30 days. Tumours grew rapidly in placebo-treated animals. Tumour growth was significantly reduced in all treatment groups. At the lowest dose tested, gemcitabine (4 mg/kg/dose), combined with frondoside A (100 μg/kg/day) was significantly more effective than with either drug alone.To conclude: The present data suggest that combinations of frondoside A and gemcitabine may provide clinical benefit for patients with pancreatic cancer.     

PUMA基因对胰腺癌细胞BxPC-3的促凋亡作用及其可能机制

目的:研究P53正向凋亡调节因子基因(P53 up-regulate modulator of apoptosis,PUMA)对胰腺癌细胞株BxPC-3凋亡的影响及其可能的作用机制.方法:以100 MOI的携PUMA基因重组腺病毒(Ad-PUMA)感染BxPC-3细胞0～96 h,流式细胞术检测BxPC-3细胞凋亡率,Western blotting检测BxPC-3细胞中PUMA、Bcl-2、Bax、Cytochrome C和Caspase-3蛋白的表达,Western blotting检测BxPC-3细胞中细胞质和线粒体内Bax的表达及Bax寡聚体.结果:随着Ad-PUMA感染时间的延长,BxPC-3细胞凋亡率逐渐增加,48 h时最高.Ad-PUMA感染促进BxPC-3细胞中PUMA、Cytochrome C和Caspase-3蛋白的表达,抑制BxPC-3细胞中Bcl-2蛋白的表达.Ad-PUMA感染后BxPC-3细胞的凋亡率与BxPC-3细胞中PUMA蛋白的表达具有明显的相关性.AdPUMA感染不影响BxPC-3细胞中Bax蛋白的总表达量,但细胞质中的Bax几乎完全消失,而线粒体中的Bax表达明显增加;AdPUMA感染诱导BxPC-3细胞中Bax蛋白的寡聚化.结论:PUMA基因通过线粒体途径促进胰腺癌细胞凋亡.     

Insulin-like growth factor binding protein-3 inhibits migration of endometrial cancer cells

Cell migration and invasion leading to metastasis is a major cause of death from endometrial cancer (EC). We have shown that the rate of EC cell migration is inversely related to the level of insulin-like growth factor protein-3 (IGFBP-3). Down-regulation of IGFBP-3 by siRNA in EC cells accelerated migration without affecting proliferation and cells displayed a more migratory phenotype, with co-localization of migration-associated markers at the leading edge of cell membranes. Opposite effects were seen with either the addition of recombinant IGFBP-3 or overexpression of IGFBP-3. Cells with mutated PTEN had the highest IGFBP-3 expression and the slowest migration rates. This study demonstrates that endogenous IGFBP-3 modulates adhesion-migration dynamics in EC cells, implying that it may be important in regulating metastasis in this disease.     

粪肠球菌脂磷壁酸激活Toll样受体2抑制胰腺导管癌BxPC-3细胞的增殖、侵袭和迁移

目的:探讨粪肠球菌脂磷壁酸(lipoteichoic acid,LTA)对胰腺导管腺癌(pancreatic ductal adenocarcinoma,PDA)BxPC3细胞增殖、侵袭和迁移的影响及其可能的机制.方法:用0、5、10、50μg/ml的LTA分别处理BxPC-3细胞,以0μg/ml组作为空白对照组,其余...     

Zoledronic acid induces antiproliferative and apoptotic effects in human pancreatic cancer cells in vitro

Bisphosphonates (BPs) are an emerging class of drugs mostly used in the palliative care of cancer patients. We investigated the in vitro activity of the most potent antiresorptive BP, zoledronic acid (ZOL), on the growth and survival of three human pancreatic cancer (PC) cell lines (BxPC-3, CFPAC-1 and PANC-1). Pancreatic cancer frequently has a dysregulated p21(ras) pathway and therefore appears to be a suitable target for BPs that interfere with the prenylation of small GTP-binding proteins such as p21(ras). We found that ZOL induces growth inhibition (IC(50):10-50 micro M) and apoptotic death of PC cells. The proapoptotic effect was correlated to cleavage/activation of caspase-9 and poly(ADP)-ribose polymerase, but not of caspase-3. Moreover, we studied the p21(ras) signalling in cells exposed to ZOL and detected a reduction of p21(ras) and Raf-1 content and functional downregulation of the terminal enzyme ERK/MAPkinase and of the pKB/Akt survival pathway. Finally, we observed that ZOL induces significant cytoskeletal rearrangements. In conclusion, we demonstrated that ZOL induces growth inhibition and apoptosis on PC cells and interferes with growth and survival pathways downstream to p21(ras). These findings might be relevant for expanding application of BPs in cancer treatment.     

TSA诱导胰腺癌BxPC-3细胞周期阻滞与凋亡的研究

目的观察曲古抑菌素A(tricho-statin A,TSA)对胰腺癌BxPC-3细胞增殖及凋亡的诱导作用,探讨TSA抗胰腺癌的作用机制。方法BxPC-3细胞应用TSA处理后采用流式细胞技术分析其细胞周期分布和细胞凋亡率,免疫组化方法检测细胞乙酰化组蛋白H4表达,Western blot分析p21 WAF1/CIP1蛋白表达。结果TSA对胰腺癌BxPC-3细胞具有生长抑制作用,且呈时间和剂量依赖性。TSA可将BxPC-3细胞阻滞于G0/G1期,TSA组G0/G1期细胞达(61.8±2.5)%,较空白对照组(42.5±2.2)%和乙醇对照组(47.3±3.4)%明显增多(P=0.004);三组细胞凋亡率分别为25.5%、5.5%和5.1%(P=0.000)。TSA组细胞p21 WAF1/CIP1蛋白表达及其相关染色质乙酰化组蛋白H4表达上调。结论TSA对胰腺癌BxPC-3细胞增殖和细胞周期具有影响作用并可诱导细胞凋亡,p21 WAF1/CIP1蛋白及其相关染色质乙酰化组蛋白H4表达上调可能是其抗胰腺癌作用机制之一。     

Serum insulin-like growth factor-I, insulin-like growth factor binding protein-3, and the risk of pancreatic cancer death

Recent epidemiological studies have shown that high serum levels of insulin-like growth factor-I (IGF-I) are associated with an increased risk of lung, colon, breast and prostate cancer. Since very few studies have addressed the role of serum levels of IGF-I in the development of pancreatic cancer, we conducted a nested case-control study to examine this association. The analysis involved 69 case subjects who died from pancreatic cancer during the follow-up period of the study, and 207 control subjects matched for sex, age(+/-1 year) and study area, selected randomly from a cohort of 10364 individuals. Serum levels of IGF-I and IGF binding protein-3 (IGFBP-3) were measured by immunoradiometric assay, using commercially available kits. The odds ratios (ORs) and 95% confidence intervals (CIs) were estimated using conditional logistic models. The levels of IGF-I were positively correlated with IGFBP-3 (r=0.55). There was a positive, but statistically insignificant association between serum levels of IGF-I and risk of death from pancreatic cancer, with subjects in the highest quartile having an OR of 2.31 (95% CI=0.70-2.64) compared to those in the lowest quartile. The risk of pancreatic cancer death increased significantly with increasing serum levels of IGFBP-3 (trend p=0.03). Further adjustment for IGFBP-3 or IGF-I slightly attenuated the positive associations. This nested case-control study showed that high serum levels of IGF-I and IGFBP-3 may be associated with an increased risk of death from pancreatic cancer.     

Insulin-like growth factor-I has different effects on myogenin induction and cell cycle progression in human alveolar and embryonal rhabdomyosarcoma cells

Alveolar rhabdomyosarcoma (RMS) has a much poorer outcome than embryonal RMS. In this study, we found that IGF-I affected the induction of myogenin and cell cycle progression in alveolar RMS cells, but not in embryonal RMS cells. IGF-I enhanced the induction of myogenin protein in alveolar RMS SJ-Rh30 and KP-RMS-MS cells as it did in myoblast C2C12 cells, but not in embryonal RMS RD or KP-RMS-KH cells. IGF-I induction of myogenin protein was blocked by anti-IGF-IR monoclonal antibody alphaIR-3 and the mTOR-specific inhibitor rapamycin. In Rh30mTOR-rr cells, which stably express a rapamycin-resistant mutant mTOR, rapamycin did not inhibit IGF-I induction of myogenin protein. These data suggest that IGF-I induces myogenin in alveolar RMS cells through the IGF-IR/mTOR pathway. In C2C12 cells, IGF-I induces myogenin protein followed by cell cycle arrest leading to myogenic differentiation. IGF-I promoted G1-S cell cycle progression without any signs of terminal differentiation in alveolar RMS cells. On the other hand, IGF-I promoted neither cell cycle arrest nor G1-S cell cycle progression in embryonal RMS cells. In alveolar RMS SJ-Rh30 cells, 4E-BP1, one of two effectors downstream of mTOR, was continuously hyperphosphorylated by IGF-I, whereas in embryonal RMS RD cells, 4E-BP1 was only transiently hyperphosphorylated. These findings suggest that the different effects of IGF-I on myogenin induction and cell cycle progression in alveolar and embryonal RMS cells are due to a difference of phosphorylation status of 4E-BP1. These different responses to IGF-I help to explain immunohistochemical and clinical behavioral differences between alveolar and embryonal RMS.     

Fluvastatin synergistically enhances the antiproliferative effect of gemcitabine in human pancreatic cancer MIAPaCa-2 cells

The new combination between the nucleoside analogue gemcitabine and the cholesterol-lowering drug fluvastatin was investigated in vitro and in vivo on the human pancreatic tumour cell line MIAPaCa-2. The present study demonstrates that fluvastatin inhibits proliferation, induces apoptosis in pancreatic cancer cells harbouring a p21ras mutation at codon 12 and synergistically potentiates the cytotoxic effect of gemcitabine. The pharmacologic activities of fluvastatin are prevented by administration of mevalonic acid, suggesting that the shown inhibition of geranyl-geranylation and farnesylation of cellular proteins, including p21rhoA and p21ras, plays a major role in its anticancer effect. Fluvastatin treatment also indirectly inhibits the phosphorylation of p42ERK2/mitogen-activated protein kinase, the cellular effector of ras and other signal transduction peptides. Moreover, fluvastatin administration significantly increases the expression of the deoxycytidine kinase, the enzyme required for the activation of gemcitabine, and simultaneously reduces the 5'-nucleotidase, responsible for deactivation of gemcitabine, suggesting a possible additional role of these enzymes in the enhanced cytotoxic activity of gemcitabine. Finally, a significant in vivo antitumour effect on MIAPaCa-2 xenografts was observed with the simultaneous combination of fluvastatin and gemcitabine, resulting in an almost complete suppression and a marked delay in relapse of tumour growth. In conclusion, the combination of fluvastatin and gemcitabine is an effective cytotoxic, proapoptotic treatment in vitro and in vivo against MIAPaCa-2 cells by a mechanism of action mediated, at least in part, by the inhibition of p21ras and rhoA prenylation. The obtained experimental findings might constitute the basis for a novel translational research in humans.