Pancreatic Carcinoma Cell Lines BxPC-3 Research Articles

A novel human single-domain antibody-drug conjugate targeting CEACAM5 exhibits potent in vitro and in vivo antitumor activity.

Leveraging the specificity of antibody to deliver cytotoxic agent into tumor, antibody-drug conjugates (ADCs) have become one of the hotspots in the development of anticancer therapies. Although significant progress has been achieved, there remain challenges to overcome, including limited penetration into solid tumors and potential immunogenicity. Fully human single-domain antibodies (UdAbs), with their small size and human nature, represent a promising approach for addressing these challenges. Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) is a glycosylated cell surface protein that rarely expressed in normal adult tissues but overexpressed in diverse cancers, taking part in tumorigenesis, progression, and metastasis. In this study, we investigated the therapeutic potential of UdADC targeting CEACAM5. We performed biopanning in our library and obtained an antibody candidate B9, which bound potently and specifically to CEACAM5 protein (KD = 4.84 nM) and possessed excellent biophysical properties (low aggregation tendency, high homogeneity, and thermal stability). The conjugation of B9 with a potent cytotoxic agent, monomethyl auristatin E (MMAE), exhibited superior antitumor efficacy against CEACAM5-expressing human gastric cancer cell line MKN-45, human pancreatic carcinoma cell line BxPC-3 and human colorectal cancer cell line LS174T with IC50 values of 38.14, 25.60, and 101.4 nM, respectively. In BxPC-3 and MKN-45 xenograft mice, administration of UdADC B9-MMAE (5 mg/kg, i.v.) every 2 days for 4 times markedly inhibited the tumor growth without significant change in body weight. This study may have significant implications for the design of next-generation ADCs.

Phycocyanin inhibits pancreatic cancer metastasis via suppressing epithelial-mesenchymal transition and targeting Akt/β-catenin pathway.

According to our previous research, phycocyanin (PC) could inhibit pancreatic tumor growth obviously. However, little is known about the effects of phycocyanin on pancreatic tumor metastasis. This study was aimed to investigate whether phycocyanin inhibits pancreatic cancer cells' metastasis and the potential underlying mechanisms. Human pancreatic carcinoma cell lines PANC-1 and BxPC3 were treated with phycocyanin (5, 10, 20, and 40 μM) for 48 h or 72 h. BALB/c nude mice were inoculated intravenously with luciferase-PANC-1 cells to establish a tumor metastasis model. BALB/c nude mice were also inoculated subcutaneously with PANC-1 cells to establish a xenograft tumor model. Our results indicated that (1) phycocyanin inhibited migration, invasion, and movement of pancreatic cancer cells in vitro, and tumor metastasis in mouse xenograft tumor model; (2) phycocyanin significantly changed cell morphology and epithelial-mesenchymal transition (EMT) phenotype in pancreatic cancer cells; (3) phycocyanin decreased the phosphorylation level of Akt and the level of nuclear β-catenin. Moreover, administration of Akt activator SC79 counteracted the inhibitory effect of phycocyanin on the migration of pancreatic cancer cells, associated with the reversal of epithelial-mesenchymal transition and Akt/β-catenin signaling pathway. Taken together, our results suggest that phycocyanin inhibits pancreatic cancer metastasis via suppressing epithelial-mesenchymal transition and targeting the Akt/β-catenin pathway.

The Radiolabeling of a Gly-Sar Dipeptide Derivative with Flourine-18 and Its Use as a Potential Peptide Transporter PET Imaging Agent.

We have developed a novel fluorine-18 radiotracer, dipeptide 1, radiolabeled in two steps from mesylate 3. The initial radiolabeling is achieved in a short reaction time (10 min) and purified through solid-phase extraction (SPE) with modest radiochemical yields (rcy = 10 ± 2%, n = 5) in excellent radiochemical purity (rcp > 99%, n = 5). The de-protection of the tert-butyloxycarbonyl (Boc) and trityl group was achieved with mild heating under acidic conditions to provide 18F-tagged dipeptide 1. Preliminary analysis of 18F-dipeptide 1 was performed to confirm uptake by peptide transporters (PepTs) in human pancreatic carcinoma cell lines Panc1, BxPC3, and ASpc1, which are reported to express the peptide transporter 1 (PepT1). Furthermore, we confirmed in vivo uptake of 18F-dipeptide tracer 1 using microPET/CT in mice harboring subcutaneous flank Panc1, BxPC3, and Aspc1 tumors. In conclusion, we have established the radiolabeling of dipeptide 1 with fluoride-18, and demonstrated its potential as an imaging agent which may have clinical applications for the diagnosis of pancreatic carcinomas.

Co-Delivery of Gemcitabine and Mcl-1 SiRNA via Cationic Liposome-Based System Enhances the Efficacy of Chemotherapy in Pancreatic Cancer.

Myeloid cell leukemia 1 (Mcl-1) overexpression is found in various human tumors and has emerged as a promising new target for pancreatic cancer treatment. Recent research has found that most pancreatic cancers develop resistance to the current first-line chemotherapeutic drug, gemcitabine (Gem), and high expression of Mcl-1 can reduce the sensitivity of pancreatic cancer cells to Gem chemotherapy. Therefore, novel strategies, such as combination therapy, to overcome resistance of Gem chemotherapy are needed urgently. Here, we employed a lipid-based delivery system (LPs) to codeliver Mcl-1 siRNA and Gem for pancreatic cancer treatment, named LP-Gem-siMcl-1. LP-Gem-siMcl-1 exhibited an increased cellular uptake, enhanced Mcl-1 down-regulation efficacy, and significant cytotoxicity in the human pancreatic carcinoma cell lines PANC-1 and BxPC-3. Furthermore, tumor inhibition in vivo proved that LP-Gem-siMcl-1 has higher anti-tumor efficiency than LP-siMcl-1 plus LP-Gem, indicating the synergistic anti-tumor effects of Gem and siMcl-1. Meanwhile, histological analysis demonstrated that LPs could efficiently co-deliver Gem and Mcl-1 siRNA to cancerous cells and overcome the resistance of Gem. Taken together, our results offer proof that LP-Gem-siMcl-1 is an effective co-delivery system to treat pancreatic cancers and may serve as a valuable tool for developing new strategies for cancer therapy.

Upregulation of ID2 antagonizes arsenic trioxide-induced antitumor effects in cancer cells.

Arsenic trioxide (ATO) strongly induces apoptosis and differentiation in acute promyelocytic leukemia, and induces cell cycle arrest in most solid tumors. Although many signaling pathways are involved in its antitumor mechanism, a detailed investigation of the transforming growth factor beta-bone morphogenetic protein signaling pathway has not been performed. A microarray containing 113 genes associated with the pathway was used to screen important molecules that participate in the antitumor effects of ATO. The expression levels of the inhibitors of DNA binding-2 (ID2) in 4 different types of cancer cells were determined by quantitative reverse transcription PCR and Western blotting. Human esophageal squamous cell carcinoma cell line Eca109 and pancreatic carcinoma cell line BxPC3 cells were transfected with siRNAs targeting ID2 and scrambled control siRNA. Cell proliferation was evaluated by methyl thiazolyl tetrazolium assay. Eighteen upregulated and 12 downregulated genes were identified. After verification at the transcriptional and translational levels in 4 different cancer cells, ID2 was identified as an ATO antitumor-associated protein. In addition, specific silencing of ID2 could enhance ATO-induced cell proliferation inhibition in cancer cells. A combination of ATO and ID2-targeted agents may have considerable therapeutic benefits in cancers.

TRAIL mutant membrane penetrating peptide alike-MuR6-TR enhances the antitumor effects of TRAIL in pancreatic carcinoma both in vitro and in vivo.

To remedy the drug resistance of natural tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) and enhance its antitumor effects, we prepared a type of TRAIL mutant membrane penetrating peptide alike (TMPPA)-TRAIL mutant R6 (MuR6-TR) by mutating the N-terminal of the soluble TRAIL gene sequence. The expressed MuR6-TR protein was purified to treat pancreatic carcinoma cell lines BxPC-3 and PANC-1. The inhibitory effects on the proliferation of BxPC-3 and PANC-1 cells was assessed with CCK-8 assay and compared with natural TRAIL. The antitumor effect of MuR6-TR was assessed on implant tumors derived from PANC-1 cells in nude mice and compared with gemcitabine. Finally, the soluble MuR6-TR gene was successfully mutated with 4 amino acids in the N-terminal of TRAIL and had a molecular size of 513 bp. The mutant MuR6-TR was connected to pET32a and verified by enzymatic digestion and sequencing. The recombinant MuR6-TR was transformed and expressed in Escherichia coli. The CCK-8 assay results indicated that MuR6-TR inhibited the growth of BxPC-3 and PANC-1 cells in a dose-dependent manner, with IC50 values of 4.63 and 7.84 ng/ml, respectively, which were much lower than that of natural TRAIL. MuR6-TR demonstrated a higher inhibitory effect on tumor growth (24.2%) than natural TRAIL (14.4%) and an effect similar to that of gemcitabine at an early period. Thus, the mutant MuR6-TR exhibited a stronger antitumor effect than that of natural TRAIL both in vivo and in vitro and may have potential therapeutic value for pancreatic carcinoma, which requires further validation.

Optimization of a Novel Peptide Ligand Targeting Human Carbonic Anhydrase IX

BackgroundCarbonic anhydrase IX (CA IX) is a hypoxia-regulated transmembrane protein over-expressed in various types of human cancer. Recently, a new peptide with affinity for human carbonic anhydrase IX (CaIX-P1) was identified using the phage display technology. Aim of the present study is to characterize the binding site in the sequence of CaIX-P1, in order to optimize the binding and metabolic properties and use it for targeting purposes.Methodology/Principal FindingsVarious fragments of CaIX-P1 were synthesized on solid support using Fmoc chemistry. Alanine scanning was performed for identification of the amino acids crucial for target binding. Derivatives with increased binding affinity were radiolabeled and in vitro studies were carried out on the CA IX positive human renal cell carcinoma cell line SKRC 52 and the CA IX negative human pancreatic carcinoma cell line BxPC3. Metabolic stability was investigated in cell culture medium and human serum. Organ distribution and planar scintigraphy studies were performed in Balb/c nu/nu mice carrying subcutaneously transplanted SKRC 52 tumors.The results of our studies clearly identified amino acids that are important for target binding. Among various fragments and derivatives the ligand CaIX-P1-4-10 (NHVPLSPy) was found to possess increased binding potential in SKRC 52 cells, whereas no binding capacity for BxPC3 cells was observed. Binding of radiolabeled CaIX-P1-4-10 on CA IX positive cells could be inhibited by both the unlabeled and the native CaIX-P1 peptide but not by control peptides. Stability experiments indicated the degradation site in the sequence of CaIX-P1-4-10. Biodistribution studies showed a higher in vivo accumulation in the tumor than in most healthy tissues.ConclusionsOur data reveal modifications in the sequence of the CA IX affine ligand CaIX-P1 that might be favorable for improvement of target affinity and metabolic stability, which are necessary prior to the use of the ligand in clinical approaches.

Grape-Seed Procyanidins Inhibit the In Vitro Growth and Invasion of Pancreatic Carcinoma Cells

Grape-seed procyanidins (GSPs) can inhibit cell proliferation and invasiveness in various human cancers. However, the effect of GSP on pancreatic carcinoma cells has not been investigated. Pancreatic carcinoma cell lines MIA PaCa-2 and BxPC-3 treated with GSP were assessed for viability by trypan blue exclusion, for cell cycle distribution by flow cytometry, for increased apoptosis by annexin V labeling, for their adhesion and invasion potential by evaluating their ability to penetrate through a matrix gel-coated Boyden chamber, and for changes in the levels of proteins involved in cellular events by immunoblotting. Grape-seed procyanidin inhibited MIA PaCa-2 and BxPC-3 proliferation in a dose-dependent manner and induced G1-phase arrest of the cell cycle in BxPC-3 or mitochondria-mediated apoptosis in MIA PaCa-2. Grape-seed procyanidin also inhibited the adhesion and invasion potential of both cell lines in a dose-dependent manner, which are associated with the suppression of metalloproteases matrix metalloproteinase 9 or 2 (MMP-9 or -2) expression. Grape-seed procyanidin inhibited the proliferation of pancreatic carcinoma cells by cell cycle blockage or apoptotic induction. The invasiveness was also suppressed by GSP through down-regulation of MMP-2 or MMP-9 in pancreatic carcinoma cells. Grape-seed procyanidin is a potential chemotherapeutic or preventive agent for pancreatic carcinoma.

In Pancreatic Carcinoma, Dual EGFR/HER2 Targeting with Cetuximab/Trastuzumab Is More Effective than Treatment with Trastuzumab/Erlotinib or Lapatinib Alone: Implication of Receptors' Down-regulation and Dimers' Disruption

We previously demonstrated the synergistic therapeutic effect of the cetuximab (anti-epidermal growth factor receptor [EGFR] monoclonal antibody, mAb)-trastuzumab (anti-HER2 mAb) combination (2mAbs therapy) in HER2low human pancreatic carcinoma xenografts. Here, we compared the 2mAbs therapy, the erlotinib (EGFR tyrosine kinase inhibitor [TKI])-trastuzumab combination and lapatinib alone (dual HER2/EGFR TKI) and explored their possible mechanisms of action. The effects on tumor growth and animal survival of the three therapies were assessed in nude mice xenografted with the human pancreatic carcinoma cell lines Capan-1 and BxPC-3. After therapy, EGFR and HER2 expression and AKT phosphorylation in tumor cells were analyzed by Western blot analysis. EGFR/HER2 heterodimerization was quantified in BxPC-3 cells by time-resolved FRET. In K-ras-mutated Capan-1 xenografts, the 2mAbs therapy gave significantly higher inhibition of tumor growth than the erlotinib/trastuzumab combination, whereas in BxPC-3 (wild-type K-ras) xenografts, the erlotinib/trastuzumab combination showed similar growth inhibition but fewer tumor-free mice. Lapatinib showed no antitumor effect in both types of xenografts. The efficacy of the 2mAbs therapy was partly Fc-independent because F(ab′)2 fragments of the two mAbs significantly inhibited BxPC-3 growth, although with a time-limited therapeutic effect. The 2mAbs therapy was associated with a reduction of EGFR and HER2 expression and AKT phosphorylation. BxPC-3 cells preincubated with the two mAbs showed 50% less EGFR/HER2 heterodimers than controls. In pancreatic carcinoma xenografts, the 2mAbs therapy is more effective than treatments involving dual EGFR/HER2 TKIs. The mechanism of action may involve decreased AKT phosphorylation and/or disruption of EGFR/HER2 heterodimerization.

Hypoxia-inducible factor-1α expression and gemcitabine chemotherapy for pancreatic cancer

The normal pancreas has an abundant blood flow, in contrast to pancreatic cancer, which is a hypovascular tumor. During hypoxia under a hypovascular environment, the transcription factor hypoxia-inducible factor-1α (HIF-1α) is activated. High HIF-1α expression reduces sensitivity to gemcitabine (GEM) which is used as a treatment for pancreatic cancer. The objective of this study was to clarify HIF-1α expression in pancreatic cancer and the association of its effects to GEM treatment. We used the human pancreatic ductal carcinoma cell lines AsPC-1 and BxPC-3 to evaluate cell proliferation, HIF-1α protein expression and sensitivity to GEM in a hypoxic environment of 1% O2 in 48 pancreatic cancer patients who received adjuvant GEM treatment after pancreatectomy. We divided the patients according to HIF-1α expression and the presence of single nucleotide polymorphisms, and we based our evaluation on the adverse events associated with GEM chemotherapy and patient outcome. The hypoxic environment promoted cell proliferation, induced HIF-1α expression and increased GEM resistance, especially in AsPC-1 cells, which included a mutant homozygote for HIF-1α(C1772T). There were no significant differences between the HIF-1α(-) and HIF-1α(+) groups in either adverse events or patient outcomes. HIF-1α enhanced neo-microvascularity in a hypoxic environment and increased drug resistance. The period until recurrence was shorter in the patients with a strong HIF-1α expression, than that in those with a weak HIF-1α expression.

Characterization of a Cancer Stem Cell-Like Side Population Derived from Human Pancreatic Adenocarcinoma Cells

To identify and partially characterize the side population cells derived from three human pancreatic adenocarcinoma cell lines. Side population cells were sorted from the human pancreatic adenocarcinoma cell lines SW1990, Capan-2, and BxPC-3 using flow cytometry and then analyzed for cell proliferation, clone formation, differentiation, chemoresistance, invasive potential, and tumorigenicity in a mouse model. Human pancreatic carcinoma cell lines SW1990, Capan-2, and BxPC-3 contain 2.7% +/- 0.35%, 3.6% +/- 1.2%, and 2.8% +/- 0.8% side population cells, respectively. We further investigated cancer stem cell characteristics with the moderately differentiated human pancreatic adenocarcinoma cell line SW1990. Flow cytometry analysis revealed that side population cells could differentiate into side population and non-side population cells and could exhibit differentiation potential. Using a clone formation assay, side population cells were shown to have a higher proliferation than non-side population cells. Compared to non-side population cells, side population cells were also more resistant to gemcitabine, a commonly used anti-cancer agent against pancreatic carcinoma, and were more invasive. Importantly, the CD133 level in side population cells was significantly higher than that in non-side population cells. The enhanced tumorigenecity was further confirmed in a male diabetic/severe combined immunodeficiency mouse model. As few as 3 x 10(3) side population cells were sufficient to induce tumor formation in the mouse model, compared to 10(7) non-side population or unsorted cells. Side population cells isolated from human pancreatic adenocarcinoma cell lines harbor cancer stem cell-like properties that may be related to the invasive potential and therapeutic-resistance of pancreatic adenocarcinoma.

Effect of human recombinant growth hormone on proliferation of pancreatic carcinoma cell line BXPC-3 and its possible mechanism

Effect of human recombinant growth hormone on proliferation of pancreatic carcinoma cell line BXPC-3 and its possible mechanism

Inhibition of pancreatic carcinoma cell growth in vitro by DPC4 gene transfection

To detect the expression of DPC4 in malignant and non-malignant specimens of human pancreas, and observe the inhibition of retroviral pLXSN containing DPC4 on pancreatic carcinoma cells in vitro. The expression of DPC4 was determined in 40 pancreatic adenocarcinoma and 36 non-malignant pancreatic specimens by reverse-transcriptase polymerase chain reaction (RT-PCR) and immunohisto-chemistry. Furthermore, we constructed retroviral vectors containing DPC4, which then infected the pancreatic carcinoma cell line BxPC-3. Cell growth in vitro after being infected was observed, and the vascular endothelial growth factor (VEGF) mRNA level in the daughter cells was determined by semi-quantitative PCR assay. The RT-PCR assay showed a positive rate of DPC4 mRNA in 100% (36/36) of normal specimens, compared to 40% (16/40) in adenocarcinoma specimens. The regional and intense positive cases of DPC4 expression in adenocarcinoma detected by immunohistochemistry were 10 and four, whereas it was all positive expression in normal tissues. There was a significant difference of DPC4 expression between them. The stable expression of DPC4 in the pancreatic carcinoma cells BxPC-3 could be resumed by retroviral vector pLXSN transfection, and could inhibit cell growth in vitro. Rather, DPC4 could decrease VEGF mRNA transcription levels. The deletion of DPC4 expression in pancreatic carcinoma suggests that loss of DPC4 may be involved in the development of pancreatic carcinoma. The retroviral vector pLXSN containing DPC4 can inhibit the proliferation of pancreatic carcinoma cells, and down-regulate the level of VEGF.

Effects of apigenin on cell proliferation of human pancreatic carcinoma cell line BxPC-3 in vitro

Objective To observe the effects of apigenin on cell proliferation of human pancreatic carcinoma cell line BxPC-3 in vitro. Methods The inhibitive effects of apigenin at different concentrations (0 μmol/L, 100 μmol/L, 200 νmol/L, and 400 μmol/L) on human pancreatic carcinoma cell line BxPC-3 were detected by MTT assays, transmission electron microscope, agarose gel electrophoresis and flow cytometry. The immunohistochemistry was used to detect the expression of Bcl-2 and Bax gene. Results Apigenin at different concentrations could inhibit the proliferation of human pancreatic carcinoma cell lines BxPC-3, and the inhibitive effect was dose-dependent. The cell cycle of pancreatic carcinoma cells was arrested at G2/M phase. The results of immunohistochemistry showed that the density of apigenin increased, and the expression of Bcl-2 gene was reduced gradually. At the same time the expression of Bax gene was enhanced. Conclusion Apigenin could inhibit the proliferation of human pancreatic carcinoma cell lines BxPC-3 in vitro. The effect of apoptosis was accompanied with the expression of Bcl-2 decrease and Bax increase.

Targeting of Heat Shock Protein 32 (Hsp32) in Neoplastic Cells by Styrene Maleic Acid Zinc Protoporphyrin (SMA-ZnPP) Is Associated with Reduced Growth and Induction of Apoptosis.

Heat shock protein 32 (Hsp32), also known as heme oxygenase-1 (HO-1), is a stress-related survival factor that has recently been implicated in enhanced survival of neoplastic cells. We here show that Hsp32/HO-1 is expressed abundantly in primary neoplastic cells in various solid tumors and hematopoietic neoplasms such as acute myeloid leukemia (AML) or chronic myeloid leukemia (CML), and in respective cell lines including the AML cell lines HL60, KG1, KG1a, and U937, CML cell lines K562 and KU812, eosinophilic leukemia cell line EOL-1, mast cell leukemia cell line HMC-1, myeloma cell lines RPMI8226 and U266, breast cancer cell line MDA MB 231, lung cancer cell line A549, pancreatic carcinoma cell line BxPC-3, colon carcinoma cell lines COLO201, COLO205, COLO320DM, and DLD-1, and the ovarian carcinoma cell line OVCAR-3. Expression of Hsp32 mRNA was demonstrable by RT-PCR and Northern blotting, and expression of the Hsp32 protein by Western blotting and immunocytochemistry. The CML-specific oncoprotein BCR/ABL and the transforming oncoprotein KIT D816V that is expressed in neoplastic mast cells, were found to promote expression of Hsp32 in Ba/F3 cells. In order to examine the functional role of Hsp32 in neoplastic cells, a specific siRNA was employed. Expression of Hsp32 siRNA resulted in reduced viability and induction of apoptosis in all cell lines tested. To further explore the value of Hsp32 as a target in neoplastic cells, a novel specific Hsp32-targeting compound, styrene maleic acid copolymer zinc protoporphyrin micelles (SMA-ZnPP) was applied. Exposure to SMA-ZnPP resulted in a significant decrease in proliferation determined by 3H-thymidine uptake, in all cell lines as well as in all primary neoplastic cells tested (AML, n=5; CML, n=5; mastocytosis, n=3; breast cancer, n=2; lung cancer, n=1). As assessed by AnnexinV-staining, Tunel assay and electron microscopy, the growth-inhibitory effects of SMA-ZnPP were found to be associated with induction of apoptosis. In each cell type, the effect of SMA-ZnPP on growth was dose-dependent and found to occur at pharmacologic concentrations (IC50 1–30 μM). Moreover, SMA-ZnPP was found to synergize with various anti-neoplastic drugs (tumor cell lines: cisplatin, leukemias: cytarabine, myeloma: bortezomib) in producing growth inhibition. In summary, these data show that Hsp32/HO-1 is an important survival factor and novel interesting target in various hematopoietic and non-hematopoietic neoplasms. Based on these data, it seems desirable to explore the value of the Hsp32-targeting drug SMA-ZnPP in clinical trials in patients with leukemias and solid tumors.

TGFbeta1 represses proliferation of pancreatic carcinoma cells which correlates with Smad4-independent inhibition of ERK activation.

Transforming growth factor beta (TGFbeta) is a tumor suppressor acting as inhibitor of cell cycle progression of epithelial cells. We show that treatment of the pancreatic carcinoma cell lines PANC-1 and BxPC-3 with TGFbeta1 inhibits both growth factor-induced activation of the extracellular signal-regulated kinase 2 (ERK2) and translocation of the kinase to the nucleus. TGFbeta1 causes a concentration-dependent reduction of cell proliferation in both cell lines. By measuring ERK activation, we can show that TGFbeta1 is able to repress ERK activation induced by mitogenic stimuli such as EGF. This inhibitory effect of TGFbeta1 is not mediated by suppression of Ras or c-Raf-1 activation, but mediated by TGFbeta1-induced activation of a serine-threonine phosphatase, as demonstrated by inhibition of phosphatases by treatment with okadaic acid. Results obtained in the Smad4-deficient pancreatic carcinoma cell line BxPC-3, demonstrate that TGFbeta1-induced growth inhibition is mediated by a Smad4-independent prevention of ERK2 activation. In contrast to the effects of TGFbeta1 on epithelial cells, mesenchymal NIH3T3 fibroblasts exhibit elevated ERK2 activation and increased cell proliferation in response to TGFbeta1 treatment. Smad4-independent phosphatase-mediated inhibition of mitogen-activated ERK2 represents a novel effector pathway contributing to suppression of epithelial pancreatic carcinoma cell proliferation by TGFbeta1, in addition to the well-known Smad-induced tumor suppressor activity of TGFbeta. Oncogene (2000) 19, 4531 - 4541.

A novel strategy for inhibiting growth of human pancreatic cancer cells by blocking cyclin-dependent kinase activity

Pancreatic cancers frequently carry mutations in the K- ras, p53, and p16 genes, which regulate cell proliferation. Transition from G1 to S phase of the cell cycle requires activation of cyclin-dependent kinase 2 (Cdk2), which is inhibited by olomoucine and roscovitine. The purpose of this study was to determine whether olomoucine and roscovitine can block Cdk2 kinase activity and inhibit proliferation of four human pancreatic cancer cell lines with various genetic alterations. Human pancreatic carcinoma cell lines BxPC-3, PANC-1, Capan-2, and CAV were treated with olomoucine or roscovitine. Cdk2 kinase activity was determined using histone H1 as the substrate. Cell cycle distribution was analyzed by DNA flow cytometry. Cell numbers were quantitated by Coulter counter. Olomoucine and roscovitine blocked Cdk2 activity in all four pancreatic cancer cell lines. Both compounds also inhibited cell proliferation in a dose-dependent fashion. Roscovitine was at least threefold more potent than olomoucine for both Cdk2 activity and cell proliferation. We have shown that Cdk inhibitors, olomoucine and roscovitine, block proliferation of human pancreatic cancer cells regardless of their mutations in K- ras, p53, or p16 genes. These compounds represent a novel therapeutic strategy with potential therapeutic benefits for pancreatic cancers.