The Clinical Impact and Molecular Biology of del(17p) in Multiple Myeloma Treated with Conventional or Thalidomide-Based Therapy

Hemizygous deletion of 17p (del(17p)) has been identified as a variable associated with poor prognosis in myeloma, although its impact in the context of thalidomide therapy is not well described. The clinical outcome of 85 myeloma patients with del(17p) treated in a clinical trial incorporating both conventional and thalidomide-based induction therapies was examined. The clinical impact of deletion, low expression, and mutation of TP53 was also determined. Patients with del(17p) did not have inferior response rates compared to patients without del(17p), but, despite this, del(17p) was associated with impaired overall survival (OS) (median OS 26.6 vs. 48.5 months, P <0.001). Within the del(17p) group, thalidomide induction therapy was associated with improved response rates compared to conventional therapy, but there was no impact on OS. Thalidomide maintenance was associated with impaired OS, although our analysis suggests that this effect may have been due to confounding variables. A minimally deleted region on 17p13.1 involving 17 genes was identified, of which only TP53 and SAT2 were underexpressed. TP53 was mutated in <1% in patients without del(17p) and in 27% of patients with del(17p). The higher TP53 mutation rate in samples with del(17p) suggests a role for TP53 in these clinical outcomes. In conclusion, del(17p) defined a patient group associated with short survival in myeloma, and although thalidomide induction therapy was associated with improved response rates, it did not impact OS, suggesting that alternative therapeutic strategies are required for this group. (C) 2011 Wiley-Liss, Inc.

Stimulating Neoblast-Like Cell Proliferation in Juvenile Fasciola hepatica Supports Growth and Progression towards the Adult Phenotype In Vitro

Fascioliasis (or fasciolosis) is a socioeconomically important parasitic disease caused by liver flukes of the genus Fasciola. Flukicide resistance has exposed the need for new drugs and/or a vaccine for liver fluke control. A rapidly improving 'molecular toolbox' for liver fluke encompasses quality genomic/transcriptomic datasets and an RNA interference platform that facilitates functional genomics approaches to drug/vaccine target validation. The exploitation of these resources is undermined by the absence of effective culture/maintenance systems that would support in vitro studies on juvenile fluke development/biology. Here we report markedly improved in vitro maintenance methods for Fasciola hepatica that achieved 65% survival of juvenile fluke after 6 months in standard cell culture medium supplemented with 50% chicken serum. We discovered that this long-term maintenance was dependent upon fluke growth, which was supported by increased proliferation of cells resembling the "neoblast" stem cells described in other flatworms. Growth led to dramatic morphological changes in juveniles, including the development of the digestive tract, reproductive organs and the tegument, towards more adult-like forms. The inhibition of DNA synthesis prevented neoblast-like cell proliferation and inhibited growth/development. Supporting our assertion that we have triggered the development of juveniles towards adult-like fluke, mass spectrometric analyses showed that growing fluke have an excretory/secretory protein profile that is distinct from that of newly-excysted juveniles and more closely resembles that of ex vivo immature and adult fluke. Further, in vitro maintained fluke displayed a transition in their movement from the probing behaviour associated with migrating stage worms to a slower wave-like motility seen in adults. Our ability to stimulate neoblast-like cell proliferation and growth in F. hepatica underpins the first simple platform for their long-term in vitro study, complementing the recent expansion in liver fluke resources and facilitating in vitro target validation studies of the developmental biology of liver fluke.