Novel functional profiling approach combining reverse phase protein microarrays and human 3-D ex vivo tissue cultures: expression of apoptosis-related proteins in human colon cancer.

Cancer is caused by a complex pattern of molecular perturbations. To understand the biology of cancer, it is thus important to look at the activation state of key proteins and signaling networks. The limited amount of available sample material from patients and the complexity of protein expression patterns make the use of traditional protein analysis methods particularly difficult. In addition, the only approach that is currently available for performing functional studies is the use of serial biopsies, which is limited by ethical constraints and patient acceptance. The goal of this work was to establish a 3-D ex vivo culture technique in combination with reverse-phase protein microarrays (RPPM) as a novel experimental tool for use in cancer research. The RPPM platform allows the parallel profiling of large numbers of protein analytes to determine their relative abundance and activation level. Cancer tissue and the respective corresponding normal tissue controls from patients with colorectal cancer were cultured ex vivo. At various time points, the cultured samples were processed into lysates and analyzed on RPPM to assess the expression of carcinoembryonic antigen (CEA) and 24 proteins involved in the regulation of apoptosis. The methodology displayed good robustness and low system noise. As a proof of concept, CEA expression was significantly higher in tumor compared with normal tissue (p<0.0001). The caspase 9 expression signal was lower in tumor tissue than in normal tissue (p<0.001). Cleaved Caspase 8 (p=0.014), Bad (p=0.007), Bim (p=0.007), p73 (p=0.005), PARP (p<0.001), and cleaved PARP (p=0.007) were differentially expressed in normal liver and normal colon tissue. We demonstrate here the feasibility of using RPPM technology with 3-D ex vivo cultured samples. This approach is useful for investigating complex patterns of protein expression and modification over time. It should allow functional proteomics in patient samples with various applications such as pharmacodynamic analyses in drug development.

Ex vivo assessment of chemotherapy-induced apoptosis and associated molecular changes in patient tumor samples.

BACKGROUND: There are inherent conceptual problems in investigating the pharmacodynamics of cancer drugs in vivo. One of the few possible approaches is serial biopsies in patients. However, this type of research is severely limited by methodological and ethical constraints. MATERIALS AND METHODS: A modified 3-dimensional tissue culture technique was used to culture human tumor samples, which had been collected during routine cancer operations. Twenty tumor samples of patients with non-small cell lung cancer (NSCLC) were cultured ex vivo for 120 h and treated with mitomycin C, taxotere and cisplatin. The cytotoxic activity of the anticancer agents was quantified by assessing the metabolic activity of treated tumor cultures and various assays of apoptosis and gene expression were performed. RESULTS: The proliferative activity of the tissue was maintained in culture as assessed by Ki-67 staining. Mitomycin C, cisplatin and taxotere reduced the metabolic activity of the tumor tissue cultures by 51%, 29% and 20%, respectively, at 120 h. The decrease in metabolic activity corresponded to the induction of apoptosis as demonstrated by the typical morphological changes, such as chromatin condensation and nuclear fragmentation. In addition, activated caspase-3 could be verified in apoptotic cells by immunohistochemistry. To verify functional aspects of apoptosis, the induction of chemotherapy-induced cell death was inhibited with the caspase inhibitor z-VAD.fmk. RNA was extracted from the tissue cultures after 120 h of ex vivo drug treatment and was of sufficient quality to allow quantitative PCR. CONCLUSION: The 3-dimensional ex vivo culture technique is a useful method to assess the molecular effects of pharmacological interventions in human cancer samples in vitro. This culture technique could become an important tool for drug development and for the prediction of in vivo drug efficacy.

PG490-mediated sensitization of lung cancer cells to Apo2L/TRAIL-induced apoptosis requires activation of ERK2.

Tumor necrosis factor-related apoptosis-inducing ligand (Apo2L/TRAIL) belongs to the family of programmed cell death-inducing cytokines. Apo2L/TRAIL induces apoptosis in a wide variety of tumor cells. Tumor cells that are resistant to Apo2L/TRAIL-induced apoptosis can be sensitized by chemotherapeutic drugs and other agents via an unknown mechanism. Here we report that PG490 (triptolide), a diterpene triepoxide extracted from the Chinese herb Tripterygium wilfordii and used in traditional Chinese medicine, sensitizes lung cancer but not normal human bronchial epithelial cells to Apo2L/TRAIL-induced apoptosis. Sensitization was accompanied by caspase-3 and caspase-8 activation, whereas no cleavage of caspase-9 was observed. Determination of cell surface receptors by flow cytometry demonstrated no difference in Apo2L/TRAIL-R1 and -R2 expression, the two receptors with functional death domains, between resistant and sensitized cells. In cells treated with the combination of Apo2L/TRAIL and PG490, we observed activation of ERK2, a member of the mitogen-activated protein kinase family. Furthermore, sensitization could be blocked by the ERK inhibitor U0126 but not the p38 inhibitor SB203580, suggesting that activation of ERK2 is required for this effect. In addition, sensitization of lung cancer cells was also seen in ex vivo culture of lung cancer tissue from four patients who underwent surgery. Immunohistochemical staining showed a clear reduction in proliferation cell nuclear antigen (PCNA) in tissue treated with Apo2L/TRAIL and PG490. In conclusion, apoptosis induced by the combination of Apo2L/TRAIL and PG490 warrants further evaluation as a potential new strategy for the treatment of lung cancer.

Phase II study of capecitabine and oxaliplatin in first- and second-line treatment of advanced or metastatic colorectal cancer.

PURPOSE: To determine the efficacy and tolerability of combining oxaliplatin with capecitabine in the treatment of advanced nonpretreated and pretreated colorectal cancer. PATIENTS AND METHODS: Forty-three nonpretreated patients and 26 patients who had experienced one fluoropyrimidine-containing regimen for advanced colorectal cancer were treated with oxaliplatin 130 mg/m(2) on day 1 and capecitabine 1,250 mg/m(2) bid on days 1 to 14 every 3 weeks. Patients with good performance status (World Health Organization grade 0 to 1) were accrued onto two nonrandomized parallel arms of a phase II study. RESULTS: The objective response rate was 49% (95% confidence interval [CI], 33% to 65%) for nonpretreated and 15% (95% CI, 4% to 35%) for pretreated patients. The main toxicity of this combination was diarrhea, which occurred at grade 3 or 4 in 35% of the nonpretreated and 50% of the pretreated patients. Grade 3 or 4 sensory neuropathy, including laryngopharyngeal dysesthesia, occurred in 16% of patients on both cohorts. Capecitabine dose reductions were necessary in 26% of the nonpretreated and 45% of the pretreated patients in the second treatment cycle. The median overall survival was 17.1 months and 11.5 months, respectively. CONCLUSION: Combining capecitabine and oxaliplatin yields promising activity in advanced colorectal cancer. The main toxicity is diarrhea, which is manageable with appropriate dose reductions. On the basis of our toxicity experience, we recommend use of capecitabine in combination with oxaliplatin 130 mg/m(2) at an initial dose of 1,250 mg/m(2) bid in nonpretreated patients and at a dose of 1,000 mg/m(2) bid in pretreated patients.

Docetaxel, cisplatin, and fluorouracil; docetaxel and cisplatin; and epirubicin, cisplatin, and fluorouracil as systemic treatment for advanced gastric carcinoma: a randomized phase II trial of the Swiss Group for Clinical Cancer Research.

PURPOSE: This randomized phase II trial evaluated two docetaxel-based regimens to see which would be most promising according to overall response rate (ORR) for comparison in a phase III trial with epirubicin-cisplatin-fluorouracil (ECF) as first-line advanced gastric cancer therapy. PATIENTS AND METHODS: Chemotherapy-naïve patients with measurable unresectable and/or metastatic gastric carcinoma, a performance status

Oxaliplatin-induced immune pancytopenia.

BACKGROUND: Oxaliplatin, a third-generation platinum compound, has been implicated in isolated cases of immune hemolytic anemia and/or immune thrombocytopenia. The first case of severe immune pancytopenia related to oxaliplatin is described. PATIENT AND METHODS: A 79-year-old woman with colorectal cancer was initially treated with 5-fluorouracil and she later received oxaliplatin and leucovorin every 2 to 4 weeks. During the 15th and 17th cycles of chemotherapy she developed thrombocytopenia, hemolysis, and neutropenia. No problems occurred during the 16th cycle without oxaliplatin. Serologic testing including detection of drug-dependent antibodies and autoantibodies was performed with standard techniques. RESULTS: Serologic findings included a positive immunoglobulin G direct antiglobulin test; nonreactive red blood cell (RBC) eluates; platelet (PLT)-bound antibodies to glycophorin (GP) IIb-IIIa, GPIb-IX, and GPIa-IIa; and oxaliplatin-dependent antibodies to PLTs, RBCs, and neutrophils. CONCLUSION: Oxaliplatin may lead to the production of ddabs to RBCs, PLTs, and neutrophils. Thus the risk of immune cytopenias should always be considered in patients treated with oxaliplatin.

Alternative splicing of the human cyclin D-binding Myb-like protein (hDMP1) yields a truncated protein isoform that alters macrophage differentiation patterns.

We have cloned two novel, alternatively spliced messages of human cyclin D-binding Myb-like protein (hDMP1). The known, full-length protein has been named hDMP1alpha and the new isoforms, hDMP1beta and hDMP1gamma. The hDMP1alpha, -beta, and -gamma splice variants have unique expression patterns in normal hematopoietic cells; hDMP1beta mRNA transcripts are strongly expressed in quiescent CD34+ cells and freshly isolated peripheral blood leukocytes, as compared with hDMP1alpha. In contrast, activated T-cells and developing myeloid cells, macrophages, and granulocytes express low levels of hDMP1beta transcripts, and hDMP1gamma is ubiquitously and weakly expressed. Mouse Dmp1 has been shown to activate CD13/aminopeptidase N (APN) and p19ARF gene expression via binding to canonical DNA recognition sites in the respective promoters. Assessment of CD13/APN promoter responsiveness demonstrated that hDMP1alpha but not hDMP1beta and -gamma, is a transcriptional activator. Furthermore, hDMP1beta was found to inhibit the CD13/APN promoter transactivation ability of hDMP1alpha. Stable, ectopic expression of hDMP1beta and, to a lesser extent hDMP1gamma, reduced endogenous cell surface levels of CD13/APN in U937 cells. Moreover, stable, ectopic expression of hDMP1beta altered phorbol 12-myristate 13-acetate-induced terminal differentiation of U937 cells to macrophages and resulted in maintenance of proliferation. These results demonstrate that hDMP1beta antagonizes hDMP1alpha activity and suggest that cellular functions of hDMP1 may be regulated by cellular hDMP1 isoform levels.