Galpha12 and Galpha13 stimulate Rho-dependent tyrosine phosphorylation of focal adhesion kinase, paxillin, and p130 Crk-associated substrate

We examined whether constitutively active mutants of the Galpha proteins Galpha12 and Galpha13, which together comprise the G12 subfamily of Galpha proteins, induce Rho-dependent tyrosine phosphorylation of the focal adhesion proteins p125 focal adhesion kinase, paxillin, and p130 Crk-associated substrate. We report that transient expression of the constitutively active mutants of Galpha12 or of Galpha13 in human embryonic kidney 293 cells stimulates tyrosine phosphorylation of a set of proteins of Mr of 110,000-130,000, 97,000, and 60,000-70,000. We identified p125 focal adhesion kinase, paxillin, and p130 Crk-associated substrate as prominent tyrosine-phosphorylated proteins in human embryonic kidney 293 cells expressing constitutively active Galpha12 and Galpha13. In common with the increased tyrosine phosphorylation of these proteins mediated by mitogens acting through heptahelical receptors, the Galpha12- and Galpha13-mediated increase in tyrosine phosphorylation is blocked by cytochalasin D, which specifically disrupts the actin cytoskeleton, and by the Clostridium botulinum C3 exoenzyme, which ADP-ribosylates and inactivates Rho. Our results support the hypothesis that Galpha12 and Galpha13 activate Rho and suggest that Galpha12 and Galpha13 may mediate the tyrosine phosphorylation of p125 focal adhesion kinase, paxillin, and p130 Crk-associated substrate.     

Complexes of focal adhesion kinase (FAK) and Crk-associated substrate (p130(Cas)) are elevated in cytoskeleton-associated fractions following adhesion and Src transformation. Requirements for Src kinase activity and FAK proline-rich motifs

The focal adhesion kinase (FAK) and Crk-associated substrate, p130(Cas) (Cas), have been implicated in diverse signaling pathways including those mediated by integrins, G-protein-coupled receptors, tyrosine kinase receptors, and the v-src and v-crk oncogenes. The recent identification of a direct interaction between FAK and Cas prompted the examination of potential regulation of FAK.Cas complexes by factors that result in concomitant increase in their phosphotyrosine content, namely cell adhesion and transformation by Src. Both conditions resulted in elevated FAK.Cas complex levels in nonionic detergent-insoluble fractions, indicating increased association with the cytoskeleton. For activated Src, this effect requires an active Src catalytic domain but not its Src homology 2 (SH2) or Src homology 3 (SH3) domains. FAK kinase domain tyrosines 576 and 577 are also required, suggesting that direct phosphorylation of these sites by Src may influence the solubility and/or stability of the complex. FAK-Cas association was only observed in the context of Cas binding to at least one of two distinct proline-rich sites on FAK. These findings firmly establish a direct interaction between FAK and Cas and demonstrate that Src can influence the subcellular localization of the complex by a tyrosine phosphorylation-dependent mechanism.     

Protein-tyrosine phosphatase Shp-2 regulates cell spreading, migration, and focal adhesion

Shp-2, a widely expressed cytoplasmic tyrosine phosphatase with two SH2 domains, is believed to participate in signal relay downstream of growth factor receptors. We show here that this phosphatase also plays an important role in the control of cell spreading, migration, and cytoskeletal architecture. Fibroblast cells lacking a functional Shp-2 were impaired in their ability to spread and migrate on fibronectin compared with wild-type cells. Furthermore, Shp-2 mutant cells displayed an increased number of focal adhesions and condensed F-actin aggregation at the cell periphery, properties reminiscent of focal adhesion kinase (FAK)-deficient cells. This is consistent with our previous observations in vivo that mice homozygous for the Shp-2 mutation died at midgestation with similar phenotype to FAK and fibronectin-deficient embryos, having severe defects in mesodermal patterning, particularly the truncation of posterior structures. Biochemical analysis demonstrated that FAK dephosphorylation was significantly reduced in Shp-2 mutant cells in suspension. Furthermore, regulated association of Src SH2 domain with FAK and paxillin during cell attachment and detachment on fibronectin was disrupted in Shp-2 mutant cells. This report defines a unique role of the Shp-2 tyrosine phosphatase in cell motility, which might guide the design of a new strategy for pharmaceutical interference of tumor metastasis.     

p125Fak focal adhesion kinase is a substrate for the insulin and insulin-like growth factor-I tyrosine kinase receptors

The focal adhesion kinase p125(Fak) is a widely expressed cytosolic tyrosine kinase, which is involved in integrin signaling and in signal transduction of a number of growth factors. In contrast to tyrosine kinase receptors such as the platelet-derived growth factor and the hepatocyte growth factor receptors, which induce p125(Fak) phosphorylation, insulin has been shown to promote its dephosphorylation. In this study, we compared p125(Fak) phosphorylation in insulin-stimulated cells maintained in suspension or in an adhesion state. We found that, in nonattached cells, insulin promotes p125(Fak) phosphorylation, whereas dephosphorylation occurred in attached cells. This was observed in Rat-1 fibroblasts overexpressing the insulin receptor, as well as in Hep G2 hepatocytes and in 3T3-L1 adipocytes expressing more natural levels of insulin receptors. Insulin-induced p125(Fak) phosphorylation correlated with an increase in paxillin phosphorylation, indicating that p125(Fak) kinase activity may be stimulated by insulin. Mixing of purified insulin or insulin-like growth factor-I (IGF-I) receptors with p125(Fak) resulted in an increase in p125(Fak) phosphorylation. Using a kinase-deficient p125(Fak) mutant, we found that this protein is a direct substrate of the insulin and IGF-I receptor tyrosine kinases. This view is supported by two additional findings. (i) A peptide corresponding to p125(Fak) sequence comprising amino acids 568-582, which contains tyrosines 576 and 577 of the kinase domain regulatory loop, is phosphorylated by the insulin receptor; and (ii) p125(Fak) phosphorylation by the insulin receptor is prevented by addition of this peptide. Finally, we observed that p125(Fak) phosphorylation by the receptor results in its activation. Our results show that the nature of the cross-talk between the insulin/IGF-I receptors and p125(Fak) is dependent on the cell architecture, and hence the interaction of the insulin/IGF-I signaling system with the integrin system will vary accordingly.     

Phosphorylation of p130Cas by angiotensin II is dependent on c-Src, intracellular Ca2+, and protein kinase C

Prorenin is expressed in certain extrarenal tissues, but normally only the kidneys process prorenin to renin and secrete renin into the circulation. Although transgenic animal lines containing the human renin (hREN) structural gene with either 0.9-kb or 3-kb 5'-flanking DNA express the transgene appropriately in renal juxtaglomerular cells and secrete hREN into the circulation, the source of the circulating renin is not known. In the present study, we observed that 13-kb hREN transgenic mice that contain the structural gene and 0.9-kb 5'-flanking DNA express hREN mRNA in many unusual tissues. We also observed that circulating hREN levels in 13-kb hREN mice increased after bilateral nephrectomy. These results suggested that the hREN gene is expressed at inappropriate locations where prorenin might be processed to renin. To determine if more distal sequences flanking the hREN gene might contribute to cell and tissue specificity, we used a 45-kb hREN genomic fragment that contained the structural gene and about 25-kb 5'- and 8-kb 3'-flanking DNA sequences to generate 3 separate transgenic lines that contained the intact transgene sequences. Ribonuclease protection assays revealed a much narrower tissue distribution of hREN expression than in the 13-kb hREN transgenic mice. In each 45-kb hREN line, hREN mRNA was present only in the kidney, adrenal, lung, eye, ovary, and brain. Moreover, 24 hours after nephrectomy, human plasma renin fell to very low levels, indistinguishable from those of nontransgenic littermates, indicating that their circulating hREN is of renal origin. These studies suggest that sequences flanking the structural gene, missing from previous hREN transgenic lines, suppress renin gene expression at inappropriate extrarenal sites where cellular proteases, to which prorenin is not normally exposed, could convert prorenin to renin, resulting in abnormal secretion of renin into the plasma.     

Opposite regulation of tyrosine-phosphorylation of p130(Cas) by insulin and insulin-like growth factor I

To investigate the difference in signaling between insulin and insulin-like growth factor I (IGF-I), we studied the effects of these hormones on the phosphorylation state of Crk-associated substrate (Cas) in cells expressing human insulin receptor (HIRc). In the basal state, Cas was heavily tyrosine-phosphorylated, and insulin dephosphorylated Cas in a time- and dose-dependent manner. On the other hand, IGF-I phosphorylated rather than dephosphorylated Cas in HIRc cells. In HIRY/F2 cells expressing a mutant insulin receptor lacking a binding site of SHP-2, a protein-tyrosine phosphatase containing src homology 2 (SH2) regions, insulin accelerated phosphorylation of Cas, as did IGF-I. In HIRc cells expressing a mutant SHP-2 lacking a PTPase domain (DeltaPTP), which interfered with SHP-2 function, insulin failed to dephosphorylate Cas. In whole cell lysate obtained in the basal state, Cas bound to a glutathione-S transferase fusion protein containing SH2 domains of SHP-2 and dissociated from this GST protein in response to insulin. These results indicate that the opposite regulation of Cas phosphorylation by insulin and IGF-I may be mediated through different properties of their receptors, and that the interaction of the insulin receptor with SHP-2 may play an important role in determining the tyrosine-phosphorylation state of Cas.     

Requirement for phosphatidylinositol 3'-kinase activity in platelet-derived growth factor-stimulated tyrosine phosphorylation of p125 focal adhesion kinase and paxillin

The role of phosphatidylinositol 3'-kinase (PI 3'-kinase) activity in platelet-derived growth factor (PDGF)-stimulated tyrosine phosphorylation of focal adhesion kinase (p125FAK) and paxillin has been examined. The tyrosine phosphorylation of p125FAK and paxillin in response to PDGF was markedly inhibited by wortmannin in a dose-dependent manner. PDGF-stimulated PI 3'-kinase activity, membrane ruffle formation, and tyrosine phosphorylation of p125FAK and paxillin were all inhibited by the same low concentrations of wortmannin (>90% inhibition at 40nM). In contrast, tyrosine phosphorylation of p125FAK and paxillin in response to bombesin, endothelin, and phorbol 12,13-dibutyrate was not inhibited by wortmannin in these cells. Furthermore, LY294002, an inhibitor of PI 3'-kinase structurally unrelated to wortmannin, also inhibited PDGF-stimulated p125FAK tyrosine phosphorylation. PDGF was shown to stimulate the tyrosine phosphorylation of p125FAK in porcine aortic endothelial (PAE) cells transfected with the wild type PDGF-beta receptors, but not in PAE cells transfected with PDGF-beta receptors in which the PI 3'-kinase binding sites (Tyr-740/751) were replaced by phenylalanine. PDGF-stimulated, PI 3'-kinase-dependent tyrosine phosphorylation of p125FAK was not inhibited by rapamycin, and thus it was dissociated from the activation of p70 S6 kinase, previously identified as a molecular downstream target of PI 3'-kinase. Thus, we have identified a PI 3'-kinase-dependent signal transduction pathway in the action of PDGF, which leads to the phosphorylation of p125FAK and paxillin.     

Differential regulation of focal adhesion kinase and mitogen-activated protein kinase tyrosine phosphorylation during insulin-like growth factor-I-mediated cytoskeletal reorganization

In SH-SY5Y human neuroblastoma cells, insulin-like growth factor (IGF)-I mediates membrane ruffling and growth cone extension. We have previously shown that IGF-I activates the tyrosine phosphorylation of focal adhesion kinase (FAK) and extracellular signal-regulated protein kinase (ERK) 2. In the current study, we examined which signaling pathway underlies IGF-I-mediated FAK phosphorylation and cytoskeletal changes and determined if an intact cytoskeleton was required for IGF-I signaling. Treatment of SH-SY5Y cells with cytochalasin D disrupted the actin cytoskeleton and prevented any morphological changes induced by IGF-I. Inhibitors of phosphatidylinositol 3-kinase (PI 3-K) blocked IGF-I-mediated changes in the actin cytoskeleton as measured by membrane ruffling. In contrast, PD98059, a selective inhibitor of ERK kinase, had no effect on IGF-I-induced membrane ruffling. In parallel with effects on the actin cytoskeleton, cytochalasin D and PI 3-K inhibitors blocked IGF-I-induced FAK tyrosine phosphorylation, whereas PD98059 had no effect. It is interesting that cytochalasin D did not block IGF-I-induced ERK2 tyrosine phosphorylation. Therefore, it is likely that FAK and ERK2 tyrosine phosphorylations are regulated by separate pathways during IGF-I signaling. Our study suggests that integrity as well as dynamic motility of the actin cytoskeleton mediated by PI 3-K is required for IGF-I-induced FAK tyrosine phosphorylation, but not for ERK2 activation.     

Dissociation of mitogen-activated protein kinase activation from p125 focal adhesion kinase tyrosine phosphorylation in Swiss 3T3 cells stimulated by bombesin, lysophosphatidic acid, and platelet-derived growth factor

The experiments presented here were designed to examine the contribution of p125 focal adhesion kinase (p125FAK) tyrosine phosphorylation to the activation of the mitogen-activated protein kinase cascade induced by bombesin, lysophosphatidic acid (LPA), and platelet-derived growth factor (PDGF) in Swiss 3T3 cells. We found that tyrosine phosphorylation of p125FAK in response to these growth factors is completely abolished in cells treated with cytochalasin D or in cells that were suspended in serum-free medium for 30 min. In marked contrast, the activation of p42mapk by these factors was independent of the integrity of the actin cytoskeleton and of the interaction of the cells with the extracellular matrix. The protein kinase C inhibitor GF 109203X and down-regulation of protein kinase C by prolonged pretreatment of cells with phorbol esters blocked bombesin-stimulated activation of p42mapk, p90rsk, and MAPK kinase-1 but did not prevent bombesin-induced tyrosine phosphorylation of p125FAK. Furthermore, LPA-induced p42mapk activation involved a pertussis toxin-sensitive guanylate nucleotide-binding protein, whereas tyrosine phosphorylation of p125FAK in response to LPA was not prevented by pretreatment with pertussis toxin. Finally, PDGF induced maximum p42mapk activation at concentrations (30 ng/ml) that failed to induce tyrosine phosphorylation of p125FAK. Thus, our results demonstrate that p42mapk activation in response to bombesin, LPA, and PDGF can be dissociated from p125FAK tyrosine phosphorylation in Swiss 3T3 cells.     

Epidermal growth factor modulates tyrosine phosphorylation of p130Cas. Involvement of phosphatidylinositol 3'-kinase and actin cytoskeleton

Epidermal growth factor (EGF) treatment of Rat-1 cells expressing human EGF receptor results in the modification of the tyrosine phosphorylation of the p130 Crk-associated substrate (Cas), a novel signaling molecule residing in focal adhesions. At low, mitogenic concentrations (<10 ng/ml), EGF treatment induced a rapid and transient tyrosine phosphorylation of Cas and promoted the formation of a Cas-adapter protein Crk complex in intact cells. The increase in tyrosine phosphorylation of Cas paralleled an increase in the cellular content of actin stress fibers and occurred via a pathway that depended on the integrity of the cytoskeleton. Further, phosphatidylinositol 3'-kinase activity was found to be required for the EGF-stimulated Cas phosphorylation and actin polymerization. At high concentrations (>30 ng/ml), EGF treatment resulted in the tyrosine dephosphorylation of Cas in a time-dependent manner with a concomitant decrease in the length and number of actin stress fibers. Thus, Cas exhibits an unusual bell-shaped dose-response curve in response to EGF stimulation. These results demonstrate a novel signaling role for EGF in inducing changes in tyrosine phosphorylation of Cas and Cas-Crk complex formation and suggest that Cas could be a signaling component in EGF-mediated signal transduction.     

Role of the retinoblastoma protein family, pRB, p107 and p130 in the negative control of cell growth

The retinoblastoma family of proteins, also known as pocket proteins, includes the product of the retinoblastoma susceptibility gene and the functionally and structurally related proteins p107 and p130. Pocket proteins control growth processes in many cell types, and this has been linked to the ability of pocket proteins to interact with a multitude of cellular proteins that regulate gene expression at various levels. By regulating gene expression, pocket proteins control cell cycle progression, cell cycle entry and exit, cell differentiation and apoptosis. This review will focus on the mechanisms of regulation of pocket proteins and how modulation of pocket protein levels and phosphorylation status regulate association with their cellular targets. The coordinated regulation of pocket proteins provides the cells with a competence mechanism for passage through certain cell growth and differentiation transitions.     

The COOH-terminal domain of the focal adhesion kinase induces loss of adhesion and cell death in human tumor cells

PURPOSE: Coronary calcium is a powerful indicator of arteriosclerosis and can be detected very precisely with electron beam tomography. The method can be applied in patients with known coronary artery disease or in asymptomatic patients at risk of arteriosclerotic disease. METHODS: The standard protocol of EBT consists of 30 to 40 slices of 3-mm thickness with a scan time of 100 ms, no overlap. No contrast medium is needed. The total scan can be performed within one breathhold. The calcium score is calculated as described by Agatston. Radiation exposure amounts to 0.8 mSv per total screen. We used spiral CT with and without ECG trigger as an alternative. RESULTS: At the University of Munich we performed an EBT scan of the heart in 1100 patients within the last year. In 567 patients coronary angiography was performed also (+/- 3 days). Confirming previous reports in the literature, we found a correlation of the calcium score with the age and gender of the patients. Severe coronary artery disease (stenoses > or = 75%) was associated with significantly more calcium than less severe CAD. The calcium score did not discriminate between one-, two- and three-vessel disease. The site of calcification does not correlate with the localization of stenoses. Thirty-three percent of the patients with significant coronary artery disease showed a normal age-adjusted calcium score; a total of 8.1% of patients with severe stenoses did not reveal any coronary calcification (score = 0). With asymptomatic patients there are only a few studies available. Soft plaques cannot be detected with EBT, but in most patients soft plaques occur together with hard plaques. Our results show that spiral CT of the newest generation may also be used for calcium screening. There was an excellent correlation of the calcium scores of EBT and spiral CT at all levels of calcification. DISCUSSION: Coronary calcium is a sensitive marker of coronary artery disease. In the clinical setting EBT is indicated in patients with known coronary artery disease (to evaluate prognosis), in patients who are unable to perform a stress test, and in patients with atypical chest pain. However, lack of calcification may be associated with severe stenoses in a minority of patients. The clinical value in asymptomatic patients needs to be defined: randomized studies are necessary. We see a possible indication in patients with known risk factors, in whom primary preventive strategies could be performed more selectively and cost-effectively.     

Tyrosine phosphorylation of focal adhesion kinase (p125FAK): regulation by cAMP and thrombin in mesangial cells

This study aimed at evaluating the influence of submaximal isometric contraction on pressure pain thresholds (PPTs) in 14 fibromyalgia (FM) patients and 14 healthy volunteers, before and after skin hypoesthesia. PPTs were determined with pressure algometry over m. quadriceps femoris before, during and following an isometric contraction. Maximum voluntary contraction (MVC) was assessed using a computerized dynamometer. A contraction of 22% MVC on average was held until exhaustion (max. 5 min) and PPTs were assessed every 30 sec. A local anesthetic cream and a control cream were applied following a double-blind design and PPTs were reassessed. In healthy volunteers PPTs increased during contraction (P < 0.001), then decreased after the end of contraction (P < 0.001) but remained above precontraction values during the 5 min of post-contraction assessments (P < 0.001). In FM patients PPTs decreased in the middle of the contraction period (P < 0.05) and remained below precontraction levels during the rest of the contraction period (P < 0.05) and during the 5 min of post-contraction assessment (immediately post-contraction NS; 2.5 min post-contraction P < 0.01; 5 min post-contraction P < 0.05). The normalized PPTs were significantly lower in patients than in controls during contraction (start P < 0.01; middle P < 0.001; end P < 0.001) and at all times during post-contraction assessments (P < 0.001). Anesthetic cream raised PPTs at rest in controls (P < 0.01) but not in FM patients, and did not influence contraction or post-contraction PPTs in either group. Therefore, the increased pressure pain sensibility in FM patients is more pronounced deep to the skin. The observed decrease of PPTs during isometric contraction in FM patients could be due to sensitization of mechanonociceptors caused by muscle ischemia and/or dysfunction in pain modulation during muscle contraction.     

Tyrosine phosphorylation of focal adhesion kinase (p125FAK) and paxillin in glomeruli from diabetic rats

A study of group comprising all road accidents caused by drivers of private cars who were under the influence of alcohol (BAC > = 0.3 g/kg; X = 1.56 +/- 0.62 g/kg) that occurred in a defined area over the span of one calendar year (n = 625) was compared with a randomly selected control group of 718 road accidents in which the drivers had not been under the influence of alcohol. The drivers in the study group were marginally younger than the ones in the control group. However, there was no evidence of an alcohol related increase in the risk of an accident associated with younger age. The sex ratio in the study group corresponded to that, generally found amongst people driving under the influence of alcohol. In the study group there was no evidence of a restricted manner and extent of car use, based on the distances between the sites of the accidents and the offenders' homes. However, the proportion of accidents occurring out of towns was greater in the study group. Alcohol associated accidents occurred more frequently in the evenings and at night, which reflects habitual drinking patterns. Therefore these accidents occurred mainly in darkness and twilight. Surprisingly, unfavorable weather conditions such as rain or ice did not lead to an increase in accidents due to alcohol. In fact, in the study group, proportionally fewer accidents occurred on icy roads. Both injury to persons and damage to property were more severe in the study group. While no relationship between accident severity and blood alcohol concentration could be proven within the study group, the risk of death or severe injury was 3 to 4 times greater in this group than in the control group.     

Acquisition of cell adhesion and induction of focal adhesion kinase of human colon cancer Colo 201 cells by retinoic acid-induced differentiation

The human colon adenocarcinoma cell lines Colo 201 and Colo 205 lose adhevise capacity to the extracellular matrix (ECM) and take on a round and floating cell shape. Treatment of these cells with all-trans-retinoic acid (RA) results in inhibition of growth and in a marked increase in the production of carcinoembryonic antigen, thereby indicating that the cells undergo differentiation. This RA-induced differentiation was accompanied by a large increase in the degree of cell adhesion with localization of E-cadherin molecules at cell-cell contact sites. We examined several adhesion molecules involved in cell-cell and cell-ECM interaction by immunoblotting, but no change in E-cadherin, intercellular adhesion molecule-1, or CD44 was observed in RA-treated Colo 201 cells. Although the adhesion of Colo 201 cells to ECM depends on the Arg-Gly-Asp sequence, levels of integrins, alpha 2, alpha 3, alpha 5, alpha V, and beta 1 in differentiated adherent cells were similar to those in untreated cells. In contrast to equivalent amounts of cell surface adhesion molecules before and after differentiation, intracellular focal adhesion kinase (FAK) was markedly induced during RA treatment, and the increase in FAK resulted in elevation of tyrosine-phosphorylated FAK. These findings suggest a role for FAK in activation of cell adhesion of RA-induced differentiation of these colon cancer cells. This may serve as an appropriate model to examine the mode of activation of the adhesive capacity of cancer cells.     

Angiostatin induces endothelial cell apoptosis and activation of focal adhesion kinase independently of the integrin-binding motif RGD

Angiostatin, a fragment of plasminogen, has been identified and characterized as an endogenous inhibitor of neovascularization. We show that angiostatin treatment of endothelial cells in the absence of growth factors results in an increased apoptotic index whereas the proliferation index is unchanged. Angiostatin also inhibits migration and tube formation of endothelial cells. Angiostatin treatment has no effect on growth factor-induced signal transduction but leads to an RGD-independent induction of the kinase activity of focal adhesion kinase, suggesting that the biological effects of angiostatin relate to subversion of adhesion plaque formation in endothelial cells.     

Genotypic analysis of tumor suppressor genes PTEN/MMAC1 and p53 in head and neck squamous cell carcinomas

OBJECTIVES: Tumor suppressor gene mutations in both p53 and PTEN/MMAC1 genomic DNA have been detected in many types of cancer. The purpose of this study was to investigate the presence and importance of PTEN/MMAC1 mutations in squamous cell carcinomas. METHODS: Exons of each gene were amplified after polymerase chain reaction (PCR) using genomic DNA derived from cell lines of squamous cell carcinoma of the head and neck (SCCHN) and snap-frozen biopsy specimens from primary established head and neck tumors. The amplified and purified DNA was then sequenced directly. RESULT: As anticipated, point mutations of the p53 gene were found in 80% of cell lines examined. A single base mutation in codon 151 was found in six of 10 cell lines studied. PTEN/MMAC1 gene mutations were found in neither the cell lines tested nor the tumor biopsy samples. CONCLUSION: This study, as well as a large volume of data, confirms that mutations of the p53 gene are frequent events in head and neck cancer cell lines. Although PTEN/MMAC1 gene mutations have been found in a variety of carcinomas, this gene was not found to be mutated in SCCHN cell lines or in primary squamous cell carcinomas of the head and neck. This information is useful for further studies of mutations in these cell lines.     

Biochemical characterization of primary peritoneal carcinoma cell adhesion, migration, and proteinase activity

The incidence and time course of arm morbidity after sector resection and axillary dissection with or without postoperative radiotherapy to the breast was assessed in a prospective randomised trial among 381 patients with stage I breast cancer. At 3-12 months, arm symptoms were reported by 59/110 of the patients who had > or = 10 lymph nodes found in the axillary specimen versus 85/253 in whom < 10 lymph nodes were found (P = 0.002); at 13-36 months, the corresponding figures were 35/106 versus 44/225 (P = 0.001). Postoperative wound complications increased the incidence of arm symptoms at 3-12 months from 104/283 to 39/79 at 3-12 months (P = 0.03). Employed patients and patients < 65 years of age reported arm symptoms at 3-12 months in 86/161 and 94/191 compared to 58/207 and 50/177 among retired patients and patients > or = 65 years of age, respectively (P = 0.0001 and P = 0.0002, respectively). In a multivariate logistic regression analysis at 3-12 months, only young age (relative risk = 0.93 per year of increasing age, 95% CI 0.91-0.97) and the number of lymph nodes found in the axillary specimen (relative risk = 1.11 per lymph node found, 95% CI 1.05-1.18) remained statistically significant. No negative impact on arm morbidity was found by the addition of postoperative radiotherapy only to the breast, either in univariate or multivariate models. We conclude that factors directly related to the extent of the surgical procedure and young age are determinants of arm morbidity after breast preserving treatment for stage I breast cancer. Arm symptoms are most common during the first year after treatment and are reduced over the subsequent 2-3 years by around 40-50%.