c-Met is a potentially new therapeutic target for treatment of human melanoma.

PURPOSE: c-Met is a receptor tyrosine kinase involved in cell growth, invasion, metastases, and angiogenesis. In this study, we investigated the role of c-Met in melanoma biology using a novel small-molecule tyrosine kinase inhibitor SU11274 and small interfering (si) RNA against the receptor. EXPERIMENTAL DESIGN: The effects of SU11274 and c-Met siRNA were studied on proliferation, apoptosis, differentiation, reactive oxygen species, and intracellular signaling. c-Met mutations were examined, and the expression of c-Met and activated c-Met was studied in nevi, primary, and metastatic melanoma. RESULTS: c-Met was expressed in 6:7 melanoma cell lines by immunoblotting. SU11274 inhibited cell growth in all melanoma cell lines by 85% to 98% with an IC(50) between 1 and 2.5 mumol/L and caused apoptosis (12-58%) in five out of six cell lines. siRNA against c-Met inhibited proliferation of melanoma cells by 60%. This is the first study that shows that SU11274 and siRNA induced microphthalmia-associated transcription factor (MITF) and several other melanoma differentiation proteins and a morphologically differentiated phenotype. SU11274 also inhibited reactive oxygen species formation and phosphorylation of c-Met receptor, AKT and S-6 kinase by the hepatocyte growth factor. A new missense c-Met mutation N948S was identified in cell lines and R988C in tumor tissue in the juxtamembrane domain of c-Met. It was found that c-Met was expressed in 88% of melanomas and 15% of nevi, and that c-Met (pY1003) was activated in 21% of human melanomas. CONCLUSION: These results support the role of c-Met in proliferation, apoptosis, differentiation, and tumor progression of melanoma. SU11274 could be used in the therapeutic inhibition of melanoma.

Functional analysis of c-Met/hepatocyte growth factor pathway in malignant pleural mesothelioma.

c-Met receptor tyrosine kinase (RTK) has not been extensively studied in malignant pleural mesothelioma (MPM). In this study, c-Met was overexpressed and activated in most of the mesothelioma cell lines tested. Expression in MPM tissues by immunohistochemistry was increased (82%) in MPM in general compared with normal. c-Met was internalized with its ligand hepatocyte growth factor (HGF) in H28 MPM cells, with robust expression of c-Met. Serum circulating HGF was twice as high in mesothelioma patients as in healthy controls. There was a differential growth response and activation of AKT and extracellular signal-regulated kinase 1/2 in response to HGF for the various cell lines. Dose-dependent inhibition (IC50 < 2.5 micromol/L) of cell growth in mesothelioma cell lines, but not in H2052, H2452, and nonmalignant MeT-5A (IC50 > 10 micromol/L), was observed with the small-molecule c-Met inhibitor SU11274. Furthermore, migration of H28 cells was blocked with both SU11274 and c-Met small interfering RNA. Abrogation of HGF-induced c-Met and downstream signaling was seen in mesothelioma cells. Of the 43 MPM tissues and 7 cell lines, we have identified mutations within the semaphorin domain (N375S, M431V, and N454I), the juxtamembrane domain (T1010I and G1085X), and an alternative spliced product with deletion of the exon 10 of c-Met in some of the samples. Interestingly, we observed that the cell lines H513 and H2596 harboring the T1010I mutation exhibited the most dramatic reduction of cell growth with SU11274 when compared with wild-type H28 and nonmalignant MeT-5A cells. Ultimately, c-Met would be an important target for therapy against MPM.

Transfer of Maternal Immune Cells by Breastfeeding: Maternal Cytotoxic T Lymphocytes Present in Breast Milk Localize in the Peyer's Patches of the Nursed Infant.

Despite our knowledge of the protective role of antibodies passed to infants through breast milk, our understanding of immunity transfer via maternal leukocytes is still limited. To emulate the immunological interface between the mother and her infant while breast-feeding, we used murine pups fostered after birth onto MHC-matched and MHC-mismatched dams. Overall, data revealed that: 1) Survival of breast milk leukocytes in suckling infants is possible, but not significant after the foster-nursing ceases; 2) Most breast milk lymphocytes establish themselves in specific areas of the intestine termed Peyer's patches (PPs); 3) While most leukocytes in the milk bolus were myeloid cells, the majority of breast milk leukocytes localized to PPs were T lymphocytes, and cytotoxic T cells (CTLs) in particular; 4) These CTLs exhibit high levels of the gut-homing molecules α4ß7 and CCR9, but a reduced expression of the systemic homing marker CD62L; 5) Under the same activation conditions, transferred CD8 T cells through breast milk have a superior capacity to produce potent cytolytic and inflammatory mediators when compared to those generated by the breastfed infant. It is therefore possible that maternal CTLs found in breast milk are directed to the PPs to compensate for the immature adaptive immune system of the infant in order to protect it against constant oral infectious risks during the postnatal phase.

Adverse events in carotid endarterectomy from a medicolegal perspective.

OBJECTIVES: Characterize factors raised in carotid endarterectomy litigation. METHODS: Outcomes, alleged causes of malpractice, and other factors were evaluated. RESULTS: Of the 37 verdicts and settlements, defendants were not liable in 25 (67.5%) cases. Frequently reported complications included stroke (51.3%) and hypoglossal nerve injury (27.0%), with other complications including airway compromise, vocal cord injury, and death. No cases reported myocardial infarction. Cerebral monitoring was mentioned in 2 cases, while inadequate informed consent, delayed diagnosis, and requirement of additional surgery were alleged in numerous instances. Settlements and jury awards averaged US$895 833 and US$1.53 million, respectively. CONCLUSIONS: Stroke and hypoglossal nerve injury are the most frequently litigated complications, and mean damages awarded were considerable. Knowledge of issues raised in our analysis may be included in a comprehensive consent process, potentially minimizing liability and improving patient safety.

From the operating room to the courtroom: a comprehensive characterization of litigation related to facial plastic surgery procedures.

OBJECTIVES/HYPOTHESIS: Malpractice litigation has increased in recent decades, contributing to higher health-care costs. Characterization of complications leading to litigation is of special interest to practitioners of facial plastic surgery procedures because of the higher proportion of elective cases relative to other subspecialties. In this analysis, we comprehensively examine malpractice litigation in facial plastic surgery procedures and characterize factors important in determining legal responsibility, as this information may be of great interest and use to practitioners in several specialties. STUDY DESIGN: Retrospective analysis. METHODS: The Westlaw legal database was examined for court records pertaining to facial plastic surgery procedures. The term "medical malpractice" was searched in combination with numerous procedures obtained from the American Academy of Facial Plastic and Reconstructive Surgery website. RESULTS: Of the 88 cases included, 62.5% were decided in the physician's favor, 9.1% were resolved with an out-of-court settlement, and 28.4% ended in a jury awarding damages for malpractice. The mean settlement was $577,437 and mean jury award was $352,341. The most litigated procedures were blepharoplasties and rhinoplasties. Alleged lack of informed consent was noted in 38.6% of cases; other common complaints were excessive scarring/disfigurement, functional considerations, and postoperative pain. CONCLUSIONS: This analysis characterized factors in determining legal responsibility in facial plastic surgery cases. Several factors were identified as potential targets for minimizing liability. Informed consent was the most reported entity in these malpractice suits. This finding emphasizes the importance of open communication between physicians and their patients regarding expectations as well as documentation of specific risks, benefits, and alternatives.

Paxillin is a target for somatic mutations in lung cancer: implications for cell growth and invasion.

Lung cancer is characterized by abnormal cell growth and invasion, and the actin cytoskeleton plays a major role in these processes. The focal adhesion protein paxillin is a target of a number of oncogenes involved in key signal transduction and important in cell motility and migration. In lung cancer tissues, we have found that paxillin was highly expressed (compared with normal lung), amplified (12.1%, 8 of 66) and correlated with increased MET and epidermal growth factor receptor (EGFR) gene copy numbers, or mutated (somatic mutation rate of 9.4%, 18 of 191). Paxillin mutations (19 of 21) were clustered between LD motifs 1 and 2 and the LIM domains. The most frequent point mutation (A127T) enhanced lung cancer cell growth, colony formation, focal adhesion formation, and colocalized with Bcl-2 in vitro. Gene silencing from RNA interference of mutant paxillin led to reduction of cell viability. A murine in vivo xenograft model of A127T paxillin showed an increase in tumor growth, cell proliferation, and invasion. These results establish an important role for paxillin in lung cancer.