Development of bioluminescent chick chorioallantoic membrane (CAM) models for primary pancreatic cancer cells: a platform for drug testing.

The aim of the present study was to develop chick-embryo chorioallantoic membrane (CAM) bioluminescent tumor models employing low passage cell cultures obtained from primary pancreatic ductal adenocarcinoma (PDAC) cells. Primary PDAC cells transduced with lentivirus expressing Firefly-luciferase (Fluc) were established and inoculated onto the CAM membrane, with >80% engraftment. Fluc signal reliably correlated with tumor growth. Tumor features were evaluated by immunohistochemistry and genetic analyses, including analysis of mutations and mRNA expression of PDAC pivotal genes, as well as microRNA (miRNA) profiling. These studies showed that CAM tumors had histopathological and genetic characteristic comparable to the original tumors. We subsequently tested the modulation of key miRNAs and the activity of gemcitabine and crizotinib on CAM tumors, showing that combination treatment resulted in 63% inhibition of tumor growth as compared to control (p < 0.01). These results were associated with reduced expression of miR-21 and increased expression of miR-155. Our study provides the first evidence that transduced primary PDAC cells can form tumors on the CAM, retaining several histopathological and (epi)genetic characteristics of original tumors. Moreover, our results support the use of these models for drug testing, providing insights on molecular mechanisms underlying antitumor activity of new drugs/combinations.

Synergistic activity of the c-Met and tubulin inhibitor tivantinib (ARQ197) with pemetrexed in mesothelioma cells.

Malignant pleural mesothelioma (MPM) is a lethal disease with scarce therapeutic options, and preclinical studies on new targeted-agents are warranted. Because previous studies reported high c-Met expression and alterations in the microtubules network in most MPM samples, we evaluated the activity of tivantinib, which has been recently suggested to affect microtubule polymerization in addition to inhibiting c-Met. In four MPM cell lines tivantinib inhibited both c-Met activity and microtubule polymerization, resulting in inhibition of cell-growth with IC50s ranging between 0.3 µM (MSTO-211H) and 2.4 µM (H2052). Furthermore tivantinib synergistically enhanced the antiproliferative and proapoptotic activity of pemetrexed, as detected by sulforhodamine-B-assay and flow cytometry. The synergistic interaction was associated with reduction of thymidylate synthase expression and inhibition of migratory activity. In aggregate, these data show the ability of tivantinib to specifically target key pathways in MPM cells and synergistically interact with pemetrexed, supporting further studies on this therapeutic approach.

Antiproliferative activity of epi-cercosporin in human solid tumor cell lines.

From cultures of Cercospora piaropi, a phytopathogenic fungus isolated from symptomatic leaves of water hyacinth was obtained a red compound, which, according to the spectroscopic data, was epi-cercosporin. It showed in vitro antiproliferative activity against the panel of human solid tumor cells HBL-100, HeLa, SW1573 and WiDr. Cell cycle studies revealed that epi-cercosporin induces accumulation of cells in G2/M phase.

Cytotoxic bioactivity of some phenylpropanoic acid derivatives.

In this study, we synthesized a series of phenylpropanoic acid derivatives based on modifications at four selected points of the molecular scaffold. The in vitro antiproliferative activities of the compounds were examined in representative human solid tumor cell lines. A SAR was established pointing out the relevance of the substituents. The best activity profiles were obtained for the derivatives bearing more lipophilic esters (GI50 3.1-21 microM).

Polymorphisms to predict outcome to the tyrosine kinase inhibitors gefitinib, erlotinib, sorafenib and sunitinib.

Conventional chemotherapeutic regimens have limited impact against most solid tumors and deal with significant toxicity. During the last years novel anticancer treatments targeting specific molecules or genes involved in cancer development are being developed to improve outcome and reduce side-effects. In particular several tyrosine-kinase inhibitors (TKIs, gefitinib, erlotinib, sorafenib and sunitinib) have been approved for the treatment of different solid tumors. Their clinical activity has been related to different clinical and biological parameters, such as the EGFR-activating mutations for gefitinib and erlotinib. However, not all clinical outcomes, including tolerability, are explained, and the identification/ validation of novel biomarkers is a viable area of research. Germline polymorphisms can be easily assessed in blood samples, and polymorphisms in EGFR, AKT1 and ABCG2 have been correlated with outcome and toxicity in lung cancer patients given EGFR-TKIs therapies. However, there are several controversial findings, influenced by differences in study design/analysis, while the prognostic/predictive role of these polymorphisms still needs to be evaluated within prospective studies. More studies on the relationship of the genotype with drug pharmacokinetics and mechanism of action are also warranted. All these studies, as well as further development and application of novel technologies to decipher genetic alterations, might contribute to the validation of selected polymorphisms as molecular markers predictive of drug activity and help in the selection of TKIs best suited to the individual patient.

DNA copy number profiles correlate with outcome in colorectal cancer patients treated with fluoropyrimidine/antifolate-based regimens.

For decades 5-fluorouracil (5-FU) has remained the treatment of choice in the adjuvant and palliative setting of colorectal cancer (CRC). The combinations of 5-FU or its oral prodrug capecitabine with irinotecan/oxaliplatin and the novel agents bevacizumab/cetuximab increased responses. However, the overall prognosis is poor, and predictive biomarkers of cytotoxic drugs activity are missing. Pharmacogenetic studies focused on candidate determinants of drug activity/metabolism, such as thymidylate synthase or dihydropyrimidine dehydrogenase, but reported controversial results. Given the heterogeneous and complex nature of CRC, it is likely that many aberrations underlying its progression can also affect therapeutic response. Therefore, high-throughput arrays for genome-wide-DNA aberrations play a pivotal role for new markers discovery by moving from hypothesis-driven, targeted-research to unbiased screening of the whole genetic spectrum. Chromosomal aberrations are critical events in tumorigenesis, and genomic regions harbouring DNA gains/losses have been identified in 85% of CRC patients. These aberrations change the expression of many genes, which might explain the differential effects of specific chemotherapeutic agents. In particular, recent studies reported correlations between DNA copy-number profiles and response to fluoropyrimidine-based regimens, such as leucovorin-modulated-5-FU+irinotecan (FOLFIRI), capecitabine+irinotecan (CAPIRI) and pemetrexed+irinotecan (ALIRI). Genome-wide profiling by oligonucleotide-based array-comparative-genomic-hybridization (aCGH) revealed genomic loci, of which the copy-number status may serve as marker for outcome after FOLFIRI and CAPIRI. Larger randomized and prospective trials of these aCGH platforms in CRC patients treated with fluoropyrimidine-based regimens are ongoing, and will ultimately demonstrate whether these findings can be of actual value to predict clinical outcome and direct the choice of therapy.

Identification of microRNA-21 as a biomarker for chemoresistance and clinical outcome following adjuvant therapy in resectable pancreatic cancer.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis. The high risk of recurrence following surgical resection provides the rationale for adjuvant therapy. However, only a subset of patients benefit from adjuvant therapy. Identification of molecular markers to predict treatment outcome is therefore warranted. The aim of the present study was to evaluate whether expression of novel candidate biomarkers, including microRNAs, can predict clinical outcome in PDAC patients treated with adjuvant therapy. METHODOLOGY/PRINCIPAL FINDINGS: Formalin-fixed paraffin embedded specimens from a cohort of 82 resected Korean PDAC cases were analyzed for protein expression by immunohistochemistry and for microRNA expression using quantitative Real-Time PCR. Cox proportional hazards model analysis in the subgroup of patients treated with adjuvant therapy (N = 52) showed that lower than median miR-21 expression was associated with a significantly lower hazard ratio (HR) for death (HR = 0.316; 95%CI = 0.166-0.600; P = 0.0004) and recurrence (HR = 0.521; 95%CI = 0.280-0.967; P = 0.04). MiR-21 expression status emerged as the single most predictive biomarker for treatment outcome among all 27 biological and 9 clinicopathological factors evaluated. No significant association was detected in patients not treated with adjuvant therapy. In an independent validation cohort of 45 frozen PDAC tissues from Italian cases, all treated with adjuvant therapy, lower than median miR-21 expression was confirmed to be correlated with longer overall as well as disease-free survival. Furthermore, transfection with anti-miR-21 enhanced the chemosensitivity of PDAC cells. CONCLUSIONS SIGNIFICANCE: Low miR-21 expression was associated with benefit from adjuvant treatment in two independent cohorts of PDAC cases, and anti-miR-21 increased anticancer drug activity in vitro. These data provide evidence that miR-21 may allow stratification for adjuvant therapy, and represents a new potential target for therapy in PDAC.

Abietane diterpenoids from Salvia pachyphylla and S. clevelandii with cytotoxic activity against human cancer cell lines.

A phytochemical study has been carried out on the aerial parts of Salvia pachyphylla and S. clevelandii. From S. pachyphylla, the known diterpenes carnosol (2), rosmanol, 20-deoxocarnosol (3), carnosic acid, isorosmanol (4), 7-methoxyrosmanol, 5,6-didehydro-O-methylsugiol (5), 8beta-hydroxy-9(11),13-abietadien-12-one (6), 11,12-dioxoabieta-8,13-diene, and 11,12-dihydroxy-20-norabieta-5(10),8,11,13-tetraen-1-one were isolated, together with the new diterpene pachyphyllone (1). From S. clevelandii, the known diterpenes rosmadial (7), 16-hydroxycarnosol (8), abieta-8,11,13-triene, and taxodone were obtained, together with carnosol (2), rosmanol, and carnosic acid. The structure of the new compound (1) was identified on the basis of spectroscopic data analysis. Several of these compounds (1-8) were evaluated against a small panel of human cancer cell lines.