Pharmacogenomic analyzis of the responsiveness of gastrointestinal tumor cell lines to drug therapy: A transportome approach.

In this study, we have addressed the pharmacogenomic basis of the response of gastrointestinal tumors to six anticancer drugs using a panel of fifteen cell lines derived from pancreatic, stomach and biliary tract cancers. We determined the constitutive expression levels of 96 genes, whose encoded proteins contribute to drug action, and identified a major gene network that contains broad selectivity nucleoside transporter genes, as well as several genes known to be involved in cell proliferation and survival. All cell lines were exposed to 5'-DFUR, 5-FU, gemcitabine, cisplatin, doxorubicin and paclitaxel for 48h and cell response was measured using MTT assays.

Human pancreatic cancer stem cells are sensitive to dual inhibition of IGF-IR and ErbB receptors.

Background: Pancreatic ductal adenocarcinoma is a particularly challenging malignancy characterized by poor responsiveness to conventional chemotherapy. Although this tumor frequently overexpresses or possesses constitutively activated variants of IGF-IR and EGFR/Her-2, clinical trials using inhibitors of these receptors have failed. ErbB receptors have been proposed as one mechanism involved in the resistance to IGF-IR inhibitors.

uPAR-controlled oncolytic adenoviruses eliminate cancer stem cells in human pancreatic tumors.

Pancreatic tumors contain cancer stem cells highly resistant to chemotherapy. The identification of therapies that can eliminate this population of cells might provide with more effective treatments. In the current work we evaluated the potential of oncolytic adenoviruses to act against pancreatic cancer stem cells (PCSC).

Characterization of human pancreatic orthotopic tumor xenografts suitable for drug screening.

Background: Efforts to identify novel therapeutic options for human pancreatic ductal adenocarcinoma (PDAC) have failed to result in a clear improvement in patient survival to date. Pancreatic cancer requires efficient therapies that must be designed and assayed in preclinical models with improved predictor ability. Among the available preclinical models, the orthotopic approach fits with this expectation, but its use is still occasional.

Connexin-26 is a key factor mediating gemcitabine bystander effect.

Gemcitabine is a nucleoside analogue with anticancer activity. Inside the cell, it is sequentially phosphorylated to generate the active drug. Phosphorylated nucleoside analogues have been shown to traffic through gap junctions.

Adenoviral-mediated overexpression of human equilibrative nucleoside transporter 1 (hENT1) enhances gemcitabine response in human pancreatic cancer.

Nucleoside-derived anticancer agents must be transported across the plasma membrane as a preliminary step to their conversion into active drugs. Hence, modulation of a specific nucleoside transporter may affect bioavailability and contribute significantly to sensitizing tumor cells to these anticancer agents. We have generated and functionally characterized a new recombinant adenovirus (Ad-hENT1) that has allowed us to overexpress the equilibrative nucleoside transporter hENT1 and to analyze its effects in human pancreatic tumor cells.

Enhancement of gemcitabine-induced apoptosis by restoration of p53 function in human pancreatic tumors.

Human pancreatic adenocarcinomas are highly resistant to conventional treatment modalities, specially to chemotherapy. Among the genes that modulate apoptosis in response to cytotoxic drugs, the role of p53 has been demonstrated to be of paramount importance. Moreover, p53 is mutated in close to 50% of pancreatic cancer, which renders attractive the reintroduction of this gene as a way to enhance the action of chemotherapeutics.

Anti-migratory and anti-angiogenic effect of p16: a novel localization at membrane ruffles and lamellipodia in endothelial cells.

Recent evidence has established different functions for the tumor suppressor protein, p16(INK4A) aside from controlling the cell cycle. Here we report that cdk4/6 inhibition blocked both human umbilical vein endothelial cells (HUVEC) spreading on a vitronectin matrix and HUVEC migration on vitronectin. p16 can also act as an anti-angiogenic molecule in vitro since HUVEC and HMEC cells transfected with Ad-p16 or treated with Antennapedia p16 peptides are unable to differentiate on a Matrigel matrix.

Adenovirus-mediated retinoblastoma 94 gene transfer induces human pancreatic tumor regression in a mouse xenograft model.

Purpose: Gene transfer of a truncated variant of the retinoblastoma (RB) gene encoding a M(r) 94000 protein that lacks the NH(2)-terminal 112 amino acid residues, termed RB94, has been shown to inhibit proliferation of several human tumor cell types. We have assessed its therapeutic effectiveness on pancreatic cancer, one of the most aggressive and therapy-resistant types of cancer. For this purpose, preclinical studies aimed to evaluate the therapeutic potential of RB94 gene transfer in pancreatic cancer were carried out.

Nucleoside transporter profiles in human pancreatic cancer cells: role of hCNT1 in 2',2'-difluorodeoxycytidine- induced cytotoxicity.

Purpose: Concentrative nucleoside transporter (CNT) 1, CNT3, equilibrative nucleoside transporter (ENT) 1, and, to a lesser extent, ENT2, appear to be the transporters responsible for 2',2'-difluorodeoxycytidine (gemcitabine; Gemzar) uptake into cells. Gemcitabine is used currently in the treatment of pancreatic cancer, but the role of specific nucleoside carrier proteins in gemcitabine cytotoxicity has not been elucidated. Indeed, it is not known which nucleoside transporters are expressed in human pancreas.

Ras-dependent oncolysis with an adenovirus VAI mutant.

Adenovirus synthesize proteins that interact with oncogene and tumor suppressor gene products to set the cell for virus replication. Mutant viruses defective in these functions replicate selectively in cancer cells and represent new tools to treat cancer. We report a selectivity strategy based on deletions of adenovirus Virus-Associated (VA) RNAs.

G1 cyclin/cyclin-dependent kinase-coordinated phosphorylation of endogenous pocket proteins differentially regulates their interactions with E2F4 and E2F1 and gene expression.

Mitogenic stimulation leads to activation of G(1) cyclin-dependent kinases (CDKs), which phosphorylate pocket proteins and trigger progression through the G(0)/G(1) and G(1)/S transitions of the cell cycle. However, the individual role of G(1) cyclin-CDK complexes in the coordinated regulation of pocket proteins and their interaction with E2F family members is not fully understood. Here we report that individually or in concert cyclin D1-CDK and cyclin E-CDK complexes induce distinct and coordinated phosphorylation of endogenous pocket proteins, which also has distinct consequences in the regulation of pocket protein interactions with E2F4 and the expression of p107 and E2F1, both E2F-regulated genes.