Expression profiling of the ovarian surface kinome reveals candidate genes for early neoplastic changes.

OBJECTIVES: We tested the hypothesis that co-coordinated up-regulation or down-regulation of several ovarian cell surface kinases may provide clues for better understanding of the disease and help in rational design of therapeutic targets. STUDY DESIGN: We compared the expression signature of 69 surface kinases in normal ovarian surface epithelial cells (OSE), with OSE from patients at high risk and with ovarian cancer. RESULTS: Seven surface kinases, ALK, EPHA5, EPHB1, ERBB4, INSRR, PTK, and TGFbetaR1 displayed a distinctive linear trend in expression from normal, highrisk, and malignant epithelium. We confirmed these results using semiquantitative reverse transcription-polymerase chain reaction and tissue array of 202 ovarian cancer samples. A strong correlate was shown between disease-free survival and the expression of ERBB4. DNA sequencing revealed two novel mutations in ERBB4 in two cancer samples. CONCLUSIONS: A distinct subset of the ovarian surface kinome is altered in the transition from high risk to invasive cancer and genetic mutation is not a dominant mechanism for these modifications. These results have significant implications for early detection and targeted therapeutic approaches for women at high risk of developing ovarian cancer.

A single point mutation in the LN domain of LAMA2 causes muscular dystrophy and peripheral amyelination.

Mutations in the gene encoding the basal lamina (BL) component laminin alpha2 (LAMA2) cause merosin-deficient congenital muscular dystrophy 1A (MDC1A), a complex disorder that includes hypomyelination and myodegeneration. In dystrophia muscularis (dy) mice bearing Lama2 mutations, myofibers and Schwann cells fail to assemble stable BLs, which are thought to be crucial for myofiber survival and Schwann cell differentiation. Here, we describe defects in a new allele of Lama2 in mice, nmf417, in which a point mutation substitutes Arg for Cys79 at a universally conserved CxxC motif in the laminin N-terminal (LN) domain; this domain mediates laminin-laminin interactions. nmf417 homozygosity caused progressive myodegeneration and severe peripheral amyelination in nerve roots, similar to previous Lama2 mutations, but without the pervasive BL thinning previously associated with the disorder. In direct contrast to the previously characterized dy and dy2J alleles, nmf417 homozygous myofibers frequently had thickened BLs. Severe amyelination in nmf417-mutant nerve roots suggested complete laminin 2 inactivation for Schwann cells, although myelinated fibers had normal BLs. The results reveal crucial roles for the LN domain CxxC motif in both nerve and muscle, but challenge expected relationships between LN-domain function, Ln2 activity and BL stability. The nmf417 mutation provides a defined animal model in which to investigate mechanisms and treatments for moderate forms of MDC1A.

Coordinate control of axon defasciculation and myelination by laminin-2 and -8.

Schwann cells form basal laminae (BLs) containing laminin-2 (Ln-2; heterotrimer alpha2beta1gamma1) and Ln-8 (alpha4beta1gamma1). Loss of Ln-2 in humans and mice carrying alpha2-chain mutations prevents developing Schwann cells from fully defasciculating axons, resulting in partial amyelination. The principal pathogenic mechanism is thought to derive from structural defects in Schwann cell BLs, which Ln-2 scaffolds. However, we found loss of Ln-8 caused partial amyelination in mice without affecting BL structure or Ln-2 levels. Combined Ln-2/Ln-8 deficiency caused nearly complete amyelination, revealing Ln-2 and -8 together have a dominant role in defasciculation, and that Ln-8 promotes myelination without BLs. Transgenic Ln-10 (alpha5beta1gamma1) expression also promoted myelination without BL formation. Rather than BL structure, we found Ln-2 and -8 were specifically required for the increased perinatal Schwann cell proliferation that attends myelination. Purified Ln-2 and -8 directly enhanced in vitro Schwann cell proliferation in collaboration with autocrine factors, suggesting Lns control the onset of myelination by modulating responses to mitogens in vivo.