Morphologic characterization of osteosarcoma growth on the chick chorioallantoic membrane

<p>Abstract</p> <p>Background</p> <p>The chick chorio-allantoic membrane (CAM) assay is a commonly used method for studying angiogenic or anti-angiogenic activities <it>in vivo</it>. The ease of access allows direct monitoring of tumour growth by biomicroscopy and the possibility to screen many samples in an inexpensive way. The CAM model provides a powerful tool to study effects of molecules, which interfere with physiological angiogenesis, or experimental tumours derived from cancer cell lines. We therefore screened eight osteosarcoma cell lines for their ability to form vascularized tumours on the CAM.</p> <p>Findings</p> <p>We implanted 3-5 million cells of human osteosarcoma lines (HOS, MG63, MNNG-HOS, OST, SAOS, SJSA1, U2OS, ZK58) on the CAM at day 10 of embryonic development. Tumour growth was monitored by <it>in vivo </it>biomicroscopy at different time points and tumours were fixed in paraformaldehyde seven days after cell grafting. The tissue was observed, photographed and selected cases were further analyzed using standard histology.</p> <p>From the eight cell lines the MNNG-HOS, U2OS and SAOS were able to form solid tumours when grafted on the CAM. The MNNG-HOS tumours showed the most reliable and consistent growth and were able to penetrate the chorionic epithelium, grow in the CAM stroma and induce a strong angiogenic response.</p> <p>Conclusions</p> <p>Our results show that the CAM assay is a useful tool for studying osteosarcoma growth. The model provides an excellent alternative to current rodent models and could serve as a preclinical screening assay for anticancer molecules. It might increase the speed and efficacy of the development of new drugs for the treatment of osteosarcoma.</p

Budding Yeast Dma Proteins Control Septin Dynamics and the Spindle Position Checkpoint by Promoting the Recruitment of the Elm1 Kinase to the Bud Neck

The first step towards cytokinesis in budding yeast is the assembly of a septin ring at the future site of bud emergence. Integrity of this ring is crucial for cytokinesis, proper spindle positioning, and the spindle position checkpoint (SPOC). This checkpoint delays mitotic exit and cytokinesis as long as the anaphase spindle does not properly align with the division axis. SPOC signalling requires the Kin4 protein kinase and the Kin4-regulating Elm1 kinase, which also controls septin dynamics. Here, we show that the two redundant ubiquitin-ligases Dma1 and Dma2 control septin dynamics and the SPOC by promoting the efficient recruitment of Elm1 to the bud neck. Indeed, dma1 dma2 mutant cells show reduced levels of Elm1 at the bud neck and Elm1-dependent activation of Kin4. Artificial recruitment of Elm1 to the bud neck of the same cells is sufficient to re-establish a normal septin ring, proper spindle positioning, and a proficient SPOC response in dma1 dma2 cells. Altogether, our data indicate that septin dynamics and SPOC function are intimately linked and support the idea that integrity of the bud neck is crucial for SPOC signalling

Leiomyosarcoma of somatic soft tissues

Leiomyosarcoma is a rare, aggressively malignant connective tissue tumor of mature adults, which arises from smooth muscle. It occurs most frequently in the uterus, bowel, vascular tissues, and less commonly in somatic soft tissue or bone. The tumor when it arises in soft tissue has distinctive histologic features which somewhat resemble malignant fibrous histiocytoma (otherwise known as myxofibrosarcoma). The Orthopaedic Oncology Service at our institution has treated 66 patients with these lesions and thus far, 1/2 of the patients have died of disease at a mean of 3 years after discovery. Factors that increase the death rate include size of the tumor, Musculoskeletal Tumor Society Stage of disease, and to a lesser extent particularly in the lower extremities, anatomic site. Radiation and chemotherapy had little direct effect on the outcome but patients treated with surgery and adjunctive agents seemed to live longer than their cohorts treated with surgery alone. The purpose of this study is a general review of the clinical and prognostic features of this cancer