Surgical management and long-term outcome of dogs with cervical spondylomyelopathy with an anchored intervertebral titanium device.

OBJECTIVE: To assess the short- and long-term outcome of an anchored intervertebral titanium device (C-LOX) for the treatment of 10 dogs with disc-associated cervical spondylomyelopathy (DACSM) and 1 dog with osseous-associated cervical spondylomyelopathy. DESIGN: Retrospective case series. METHODS: Dogs were included if they were diagnosed with either DACSM or osseous-associated cervical spondylomyelopathy via myelography with or without advanced imaging and underwent surgical distraction and stabilisation of the affected intervertebral disc with a C-LOX implant. Assessment included short-term neurological outcome, radiography immediately and 6 weeks' postsurgery, owner questionnaire and veterinary clinical assessment. RESULTS: The mean follow-up time was 12 months. Improvement in neurological status was noted in 10 of 11 dogs. Screw loosening or subsidence occurred in five dogs. Revision surgery was performed in two dogs due to implant fracture (n = 1) and recurrence of spinal cord compression due to endplate subsidence around the implant (n = 1). Adjacent segment disease occurred in three dogs (30%) with DACSM at a mean of 11 months postsurgery. CONCLUSION: The use of the C-LOX implant for dogs with cervical spondylomyelopathy resulted in a high rate of initial neurological improvement; however, there is a moderate incidence of minor and major complications that is comparable to previously described distraction-stabilisation techniques.

HDAC inhibitors induce tumor-cell-selective pro-apoptotic transcriptional responses.

The identification of recurrent somatic mutations in genes encoding epigenetic enzymes has provided a strong rationale for the development of compounds that target the epigenome for the treatment of cancer. This notion is supported by biochemical studies demonstrating aberrant recruitment of epigenetic enzymes such as histone deacetylases (HDACs) and histone methyltransferases to promoter regions through association with oncogenic fusion proteins such as PML-RARα and AML1-ETO. HDAC inhibitors (HDACi) are potent inducers of tumor cell apoptosis; however, it remains unclear why tumor cells are more sensitive to HDACi-induced cell death than normal cells. Herein, we assessed the biological and molecular responses of isogenic normal and transformed cells to the FDA-approved HDACi vorinostat and romidepsin. Both HDACi selectively killed cells of diverse tissue origin that had been transformed through the serial introduction of different oncogenes. Time-course microarray expression profiling revealed that normal and transformed cells transcriptionally responded to vorinostat treatment. Over 4200 genes responded differently to vorinostat in normal and transformed cells and gene ontology and pathway analyses identified a tumor-cell-selective pro-apoptotic gene-expression signature that consisted of BCL2 family genes. In particular, HDACi induced tumor-cell-selective upregulation of the pro-apoptotic gene BMF and downregulation of the pro-survival gene BCL2A1 encoding BFL-1. Maintenance of BFL-1 levels in transformed cells through forced expression conferred vorinostat resistance, indicating that specific and selective engagement of the intrinsic apoptotic pathway underlies the tumor-cell-selective apoptotic activities of these agents. The ability of HDACi to affect the growth and survival of tumor cells whilst leaving normal cells relatively unharmed is fundamental to their successful clinical application. This study provides new insight into the transcriptional effects of HDACi in human donor-matched normal and transformed cells, and implicates specific molecules and pathways in the tumor-selective cytotoxic activity of these compounds.

Endothelial cell dysfunction and cytoskeletal changes associated with repression of p16(INK4a) during immortalization.

The immortalization process is a fundamental step in the development of most (if not all) human cancers, including the aggressive endothelial cell (EC)-derived malignancy angiosarcoma. Inactivation of the tumor suppressor p16(INK4a) and the development of multiple chromosomal abnormalities are features of angiosarcoma that are recapitulated during telomerase-mediated immortalization of human ECs in vitro. The present study used a panel of telomerase-immortalized bone marrow EC (BMEC) lines to define the consequences of inactivation of p16(INK4a) on EC function and to identify molecular changes associated with repression of p16(INK4a). In a comparison of two immortalized BMEC mass cultures and six clones, the cell lines that repressed p16(INK4a) showed a higher rate of proliferation and an impaired ability to undergo morphogenic differentiation and form vessel-like structures in vitro. Proteomic comparison of a p16(INK4a)-negative and a p16(INK4a)-positive BMEC mass culture at early- and late-passage time points following transduction with telomerase reverse transcriptase (hTERT) revealed altered expression of cytoskeletal proteins, including vimentin and α-tropomyosin (αTm), in the immortal cells. Immunoblot analyses of a panel of 11 immortal clones showed that cells that lacked p16(INK4a) expression tended to accumulate more dramatic changes in these cytoskeletal proteins than cells that retained p16(INK4a) expression. This corresponded with aberrant cytoskeletal architectures among p16(INK4a)-negative clones, which featured thicker actin stress fibers and less fluid membrane ruffles than p16(INK4a)-positive cells. A direct link between p16(INK4a) repression and defective EC function was confirmed by analysis of normal cells transfected with small interfering RNA (siRNA) targeting p16(INK4a). siRNA-mediated repression of p16(INK4a) significantly impaired random motility and vessel formation in vitro. This report is the first to demonstrate that ECs that repress the expression of p16(INK4a) are prone to defects in motility, morphogenesis and cytoskeletal organization. These defects are likely to reflect alterations that occur during the development of EC-derived malignancies.

Identification of human papillomavirus DNA gene sequences in human breast cancer.

Human papilloma viruses (HPVs) are accepted as being carcinogenic in human cervical and anogenital cancers. The suspicion that HPVs may also have a role in human breast cancer is based on the identification of HPVs in human breast tumours and the immortalisation of normal human breast cells by HPV types 16 and 18. For this investigation, DNA that had been previously extracted and fresh frozen at -70 degrees C from 50 unselected invasive ductal breast cancer specimens were screened by polymerase chain reaction (PCR) for HPV type 16, 18 and 33 gene sequences. We show that HPV 18 gene sequences are present in DNA extracted from breast tumours in Australian women. Overall, 24 (48%) of the 50 samples were HPV positive. Overall no correlations with tumour grade, patient survival, steroid receptor status, ERB-2, p53 expression and mutation were observed. Human papilloma viruses may have a role in human breast cancer. We speculate that HPVs may be transmitted by hand from the female perineum to the breast.