Novel therapies for pancreatic adenocarcinoma.

Despite advances in our understanding of the molecular and genetic basis of pancreatic cancer, the disease remains a clinical challenge. Gemcitabine, the standard chemotherapy for pancreatic cancer, offers modest improvement of tumor-related symptoms and marginal advantage of survival. New approaches, alone and in combination with gemcitabine, are being developed to combat this cancer.

The proteasome inhibitor bortezomib synergizes with gemcitabine to block the growth of human 253JB-V bladder tumors in vivo.

Bortezomib (PS-341, Velcade) is a dipeptidyl boronic acid inhibitor of the 20S proteasome that was developed as a therapeutic agent for cancer. Here, we investigated the effects of bortezomib on the growth of human 253JB-V bladder cancer cells. Although the drug did not stimulate significant increases in levels of apoptosis, it inhibited cell growth in a concentration-dependent fashion and augmented the growth inhibitory effects of gemcitabine in vitro.

The proteasome inhibitor bortezomib enhances the activity of docetaxel in orthotopic human pancreatic tumor xenografts.

Bortezomib (Velcade, formerly known as PS-341) is a boronic acid dipeptide derivative, which is a selective and potent inhibitor of the proteasome. We examined the antitumor activity of combination therapy with bortezomib + docetaxel in two human pancreatic cancer cell lines (MiaPaCa-2 and L3.6pl) selected for their divergent responses to bortezomib alone.

Quantitative analysis of biomarkers defines an optimal biological dose for recombinant human endostatin in primary human tumors.

Purpose: In a recent study, we presented preliminary evidence for biological activity in a Phase I dose-finding study (15-600 mg/m(2)) of recombinant human endostatin in patients with refractory solid tumors. Here, we conducted additional biomarker analyses to correlate changes in tumor biology with dose.

Experimental Design: Excisional tumor biopsies were obtained at baseline and after 56 days of endostatin therapy.

The proteasome inhibitor bortezomib stabilizes a novel active form of p53 in human LNCaP-Pro5 prostate cancer cells.

Advanced prostate cancer is resistant to current therapeutic strategies. Bortezomib (Velcade; previously called PS-341) is a potent and specific inhibitor of the 26S proteasome that is currently in clinical trials for treatment of various malignancies, including prostate cancer. We investigated the effects of bortezomib on p53 in the LNCaP-Pro5 prostate cancer cell line.

Differential effects of the proteasome inhibitor bortezomib on apoptosis and angiogenesis in human prostate tumor xenografts.

Bortezomib (Velcade, PS-341) is a dipeptide boronate inhibitor of the 26S proteasome developed for use in cancer therapy. Here we examined the effects of bortezomib on apoptosis and angiogenesis in derivatives of two popular human prostate cancer cell lines (LNCaP-Pro5 and PC3M-Pro4). Bortezomib strongly inhibited proliferation in both cell lines in vitro, but the PC3M-Pro4 cells were significantly more sensitive than the LNCaP-Pro5 cells to bortezomib-induced apoptosis.

Effects of the proteasome inhibitor, bortezomib, on apoptosis in isolated lymphocytes obtained from patients with chronic lymphocytic leukemia.

Purpose: Bortezomib is a peptide boronic acid inhibitor of the proteasome developed for cancer therapy. The compound is being evaluated currently in Phase II and III clinical trials. Here we characterized the effects and mechanisms of action of bortezomib in cells obtained from patients with chronic lymphocytic leukemia (CLL).

Fully human anti-interleukin 8 antibody inhibits tumor growth in orthotopic bladder cancer xenografts via down-regulation of matrix metalloproteases and nuclear factor-kappaB.

Purpose: We previously demonstrated that overexpression of interleukin 8 (IL-8) in human transitional cell carcinoma (TCC) resulted in increased tumorigenicity and metastasis. This increase in tumor growth and metastasis can be attributed to the up-regulation in the expression and activity of the metalloproteinases MMP-2 and MMP-9.

Experimental Design: To investigate whether targeting IL-8 with a fully human anti-IL-8 antibody (ABX-IL8) could be a potential therapeutic strategy for controlling TCC growth, we studied its effects on TCC growth in vitro and in an in vivo mouse model.

Nuclear factor-kappaB mediates angiogenesis and metastasis of human bladder cancer through the regulation of interleukin-8.

Purpose: Interleukin (IL)-8 is an important mediator of angiogenesis, tumorigenicity, and metastasis in transitional cell carcinoma (TCC) of the bladder. Nuclear factor kappaB (NF-kappaB)/relA regulates IL-8 expression in several neoplasms. The purpose of this study was to determine whether the organ microenvironment (hypoxia, acidosis) regulates the expression of IL-8 in TCC via NF-kappaB, and whether inhibition of NF-kappaB function by mutant IkappaB-alpha prevents induction of IL-8 expression.

Surrogate markers in antiangiogenesis clinical trials.

Novel antiangiogenic agents currently being developed may ultimately be more effective against solid tumours and less toxic than cytotoxic chemotherapy. As a result of the early clinical trials of angiogenesis inhibitors, investigators are beginning to appreciate the complexity of targeting angiogenesis and the realisation that developing clinically useful antiangiogenic therapy will be more challenging than originally thought. It is now apparent that new methods and surrogate markers to assess these agents' biological activity are crucial for their successful development.

Inhibition of proliferation of PC3 cells by the branched-chain fatty acid, 12-methyltetradecanoic acid, is associated with inhibition of 5-lipoxygenase.

Background: Branched-chain fatty acids or fatty alcohols have been reported to possess anti-tumor activity in various tumor models. Here we study 12-methyltetradecanoic acid (12-MTA), a branched-chain fatty acid, isolated from a sea cucumber extract, on the growth of prostate cancer cells and investigate the underlying mechanisms of its effect.

Methods: 12-MTA was evaluated by MTT assay for its ability to inhibit cell proliferation in various cancer types.

Automated quantification of apoptosis after neoadjuvant chemotherapy for breast cancer: early assessment predicts clinical response.

Purpose: A large body of evidence implicates apoptosis in the effects of cancer chemotherapeutic agents on tumor cells in vitro and tumor xenografts in vivo, but the predictive value of apoptosis as an early marker for clinical response in cancer patients remains unclear.

Experimental Design: We developed an automated, laser scanning cytometer-based method to quantify the percentage of tumor cells containing DNA fragmentation characteristic of apoptosis in tumor sections. We measured levels of apoptosis in a panel of 15 matched, 18-gauge core breast cancer biopsies obtained before and 48 h after neoadjuvant therapy with docetaxel plus doxorubicin or paclitaxel as part of two prospective clinical trials.

Adenoviral transfer of mda-7 leads to BAX up-regulation and apoptosis in mesothelioma cells, and is abrogated by over-expression of BCL-XL.

Background: Malignant pleural mesothelioma (MPM) is unresponsive to conventional therapies. Forced expression of the novel tumor suppressor mda-7 gene in other cell types has resulted in decreased growth and apoptosis. We evaluated cell growth, apoptosis and tumor suppressor characteristics following forced expression of this gene in mesothelioma cell lines.

Chemotherapy-induced apoptosis and Bcl-2 levels correlate with breast cancer response to chemotherapy.

Purpose: The relevance of apoptosis to breast cancer response to chemotherapy is unclear. We investigated whether changes in tumor cell apoptosis and Bcl-2 expression immediately after chemotherapy correlated with response to breast cancer treatment.

Patients And Methods: Serial core biopsies of 25 breast cancer primary tumors were performed at either two or three time points: before treatment (N = 24) and approximately 24 hours (N = 22) and/or 48 hours (N = 19) after the initiation of the first cycle of chemotherapy.

Adenoviral-mediated retinoblastoma 94 produces rapid telomere erosion, chromosomal crisis, and caspase-dependent apoptosis in bladder cancer and immortalized human urothelial cells but not in normal urothelial cells.

Retinoblastoma (RB)94, which lacks the NH(2)-terminal 112 amino acid residues of the full-length RB protein (RB110), is a more potent tumor and growth suppressor than RB110. In this study, Ad-RB94, but not Ad-RB110, produced marked growth inhibition, cytotoxicity, caspase-dependent apoptosis, and G(2)-M block in the human RB-negative, telomerase-positive bladder cancer cell line UM-UC14. This effect was completely inhibited by pretreatment with caspase inhibitors (P < 0.

Effects of the proteasome inhibitor PS-341 on apoptosis and angiogenesis in orthotopic human pancreatic tumor xenografts.

Recent studies have shown that the transcription factor, nuclear factor kappaB (NF-kappaB), regulates critical survival pathways in a variety of different cell types, including human pancreatic cancer cells. The activation of NF-kappaB is controlled by proteasome-mediated degradation of its endogenous polypeptide inhibitor, inhibitor of nuclear factor kappaBalpha. We investigated the effects of PS-341, a peptide boronate inhibitor of the proteasome in human pancreatic cancer cells in vitro and in vivo.

Inhibition of the phosphatidylinositol 3'-kinase-AKT pathway induces apoptosis in pancreatic carcinoma cells in vitro and in vivo.

The phosphatidylinositol 3'-kinase (PI3k)-AKT survival pathway is activated in many malignancies. We observed constitutive AKT phosphorylation (on S473) consistent with pathway activation in seven of nine human pancreatic carcinoma cell lines in vitro. Exposure of the cells to two structurally distinct inhibitors of PI3k (worthmannin and LY294002) resulted in a dose-dependent induction of apoptosis in six of seven of the cell lines that displayed constitutive AKT phosphorylation but not in either of the cell lines that did not.

Development of biologic markers of response and assessment of antiangiogenic activity in a clinical trial of human recombinant endostatin.

Purpose: Angiogenesis is a target for the treatment of cancer and other diseases, and its complex biology suggests that establishing the appropriate dose and schedule for antiangiogenic treatment will require extensive study. We present the initial results of a dose-finding clinical trial of recombinant human endostatin (rh-Endo) that examined potential surrogates for response to antiangiogenic therapy.

Patients And Methods: Twenty-five patients were treated with escalating doses of rh-Endo.

Phase I study of recombinant human endostatin in patients with advanced solid tumors.

Purpose: Endostatin, a 20-kd fragment of collagen XVIII, is a potent inhibitor of angiogenesis. We evaluated recombinant human endostatin (rh-Endo) in a phase I trial designed to assess safety, pharmacokinetics, and serum markers of angiogenesis in patients with solid tumors.

Patients And Methods: Twenty-six patients were enrolled onto a dose-finding trial of rh-Endo administered as an intravenous bolus over a 20-minute period once daily.

Increased apoptosis in metastatic human colonic adenocarcinomas.

Recent work suggests that apoptosis is disrupted during the progression of many solid tumors. Isogenic metastatic colon adenocarcinoma cells displayed significantly higher levels of staurosporine-induced apoptosis compared to their nonmetastatic counterparts in vitro. In addition, analysis of 15 matched primary tumors and liver metastases demonstrated that the levels of apoptosis were significantly higher in the metastases, and this increased cell death was associated with significantly lower levels of Bcl-2 protein expression.

Comparative study of various biological parameters, including expression of survivin, between primary and metastatic human colonic adenocarcinomas.

Background: Hepatic metastasis of colorectal carcinomas is the most important factor in prognosis. We examined the level of apoptosis and proliferation, the expression of survivin, bcl-2, p53 and intratumoral microvessel density (IMVD) in paired tissue specimens of primary human colon tumors and hepatic metastases and determined the molecular biological changes of the tumor cells in liver metastasis.

Materials And Methods: We examined, immunohistochemically, the level of apoptosis and proliferation, the expression of survivin, bcl-2 p53 and intratumoral microvessel density in 37 paired tissue specimens of primary colon tumors and hepatic metastases.

Disruption of Mekk2 in mice reveals an unexpected role for MEKK2 in modulating T-cell receptor signal transduction.

MEKK2 is a member of the mitogen-activated protein kinase (MAPK) kinase kinase gene family involved in regulating multiple MAPK signaling pathways. To elucidate the in vivo function of MEKK2, we generated mice carrying a targeted mutation in the Mekk2 locus. Mekk2(-/-) mice are viable and fertile.

Role of P38 MAPK, AP-1, and NF-kappaB in interleukin-1beta-induced IL-8 expression in human vascular smooth muscle cells.

Interleukin (IL)-1 modulates the expression of various genes in normal and tumor cells. We investigated the molecular mechanisms underlying IL-1beta-induced expression of IL-8 mRNA and protein in human vascular smooth muscle cells (hVSMCs). P38 mitogen-activated protein kinase (MAPK) was activated after 5min of IL-1beta treatment, whereas the extracellular signal-regulated kinases, the c-jun amino-terminal kinases, and protein kinase B/Akt were not activated by IL-1beta.