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S Winawer

Publications and source records attributed to S Winawer.

35 records · Page 2Linked to original sources
PubMed1989

Tyrosine phosphorylation of a Mr 63,000 protein induced by an endogenous mitogen in human colon carcinoma cells, but not in normal colonocytes.

Transformation of normal human colonocytes makes them sensitive to new mitogenic signals. Long-chain diglycerides (LCDGs) found in the human colon are mitogens selective for colon tumor cells, inducing mitogenesis in premalignant cells from each of 13 adenomas and in malignant cells from two of four carcinomas, but having no mitogenic effects on normal colonocytes (E. Friedman, P. Isaksson, J. Rafter, B. Marian, S. Winawer, and H. Newmark, Cancer Res., 49:544-548, 1989). Parallel to this biological activity pattern, LCDGs induce protein phosphorylation only in adenomas and carcinomas. Immunoblotting with an anti-phosphotyrosine monoclonal antibody demonstrated that the LCDG dimyristin, at concentrations found within the body, induced a 6-fold increase of tyrosine phosphorylation of an Mr 63,000 protein found in the particulate fraction of colon carcinoma cells. Tyrosine phosphorylation was maximal 0.5 min after addition of the LCDG, then fell, but remained elevated 40% over constitutive levels for at least 6 h. The Mr 63,000 tyrosine phosphoprotein was found in each of four colon carcinoma cell lines and an adenoma, but not in normal colonocytes, suggesting that the tyrosine kinase is activated only in tumor cells. Constitutive levels of the Mr 63,000 substrate were enhanced 2-fold by incubation of cells for 20 h with sodium orthovanadate, a tyrosine phosphatase inhibitor. This result suggested that carcinoma cells continually phosphorylate and dephosphorylate this tyrosine kinase substrate during growth. Thus, the colon tumor cell mitogen, dimyristin, utilizes a signal transduction pathway, containing the Mr 63,000 tyrosine kinase substrate, which is already in use during cell growth, possibly by other mitogens or growth factors.

Carcinoma↗
PubMed1989

Heterogeneity in the response of familial polyposis epithelial cells and adenomas to increasing levels of calcium in vitro.

A biomarker of increased risk for colon cancer is abnormally high proliferation of colonic epithelial cells. The authors developed an in vitro assay that measures the ability of human colonic epithelial cells that are in progressive stages of abnormal development to respond to direct application of calcium as the chloride in tissue culture medium. Incorporation of 3H-thymidine and autoradiography in situ was employed to measure the number of proliferating cells cultured at 0.1 mM CaCl2, the optimum level for growth, and 2.2 to 5 mM, both levels achievable in the colonic lumen. Abnormal cell proliferation was reduced in biopsies from 13 of 14 patients without familial polyposis but at increased risk for colon cancer because of previous colonic neoplasms or familial association; in cells from three of four asymptomatic individuals in familial polyposis families at risk for that disease; and in cells of three of ten patients symptomatic with familial polyposis. Growth of tubular adenoma cells from two of seven familial polyposis patients was also inhibited by calcium. Growth inhibition was not observed in more advanced colon tumors including eight adenomas, either villotubular or villous, and five carcinomas. These findings indicate heterogeneity within the familial polyposis phenotype for the normal cellular response to growth inhibition by calcium, and a further loss of response to calcium as these cells progress toward malignancy.

Adenoma↗
PubMed1989

Fecal diglycerides as selective endogenous mitogens for premalignant and malignant human colonic epithelial cells.

Diglycerides (DGs) have been found in fecal extracts at concentrations which induce mitogenesis of adenoma and some carcinoma cells but not normal cells in primary culture. DGs containing stearic, oleic, palmitic, and myristic acid side chains were found in fecal extracts from each of eight subjects. Synthetic 1,2-DGs, containing the fatty acids found in endogenous fecal DGs, induced mitogenesis in cultures of premalignant cells from each of 13 adenomas, covering all histological classes, and in cultures from two of four carcinomas. The potent adenoma mitogen, dimyristin, had no mitogenic activity on cultures of normal colonic epithelial cells from seven different subjects. These results suggest DGs may act as endogenous mitogens in the development of human colon cancer. The extent of adenoma mitogenesis was correlated with the chain length of the saturated R-groups: 16 greater than 14 greater than 12 greater than 10 greater than 8 much greater than 18. DGs with oleic acid residues, C18:1, were among the most active, while substitution of even one fatty acid residue with a stearic acid residue, C18:0, reduced or eliminated mitogenic activity. Dimyristin also induced enhanced levels of urokinase secretion from carcinoma cells, in parallel to the phorbol ester tumor promoter, 12-O-tetradecanoylphorbol-13-acetate. These results imply that DGs found in the colon induce a selective growth of benign colonic tumors and some carcinomas, and may enhance the invasive capacity of carcinomas, while leaving normal cells unaffected.

Adenoma↗
PubMed1988

Effects of psyllium fiber and short-chain organic acids derived from fiber breakdown on colonic epithelial cells from high-risk patients.

The effect of a purified fiber, psyllium and the short-chain organic acids derived from fiber breakdown, were assayed on isolated colonic epithelial cells primary-cultured from patients at high-risk of colon cancer, due to adenoma growth or family history of colon cancer. Psyllium fiber provided colonocytes some protection from deoxycholic acid-induced lysis. Propionic acid, a product of fiber breakdown, was a potent colonocyte mitogen, suggesting that fiber could indirectly protect the colon by providing colonocyte nutrients.

Adult↗
PubMed1987

Defining conditions to promote the attachment of adult human colonic epithelial cells.

An improved method for the attachment and growth of normal human colonic epithelial cells from minute 1 to 3-mm3 biopsies has been developed. This yields four times as many cultured cells per biopsy than older methods, with a success rate of 97% in a series of 29 biopsies. Fetal bovine serum was eliminated from the medium, the medium pH was decreased to 6.7, the oxygen tension in the incubator was decreased to 3%, and the NCTC 168 medium was supplemented with ethanolamine, phosphoethanolamine, hydrocortisone, ascorbic acid, transferrin, glutamine, insulin, epidermal growth factor, pentagastrin, and deoxycholic acid. The best substrate for cell attachment was a mixture of ungelled collagen I and bovine serum albumin. This substrate was better than the identical mixture with fibronectin added, fibronectin alone, a thin gelatin film, collagen IV with or without fibronectin, and basement membrane preparations from four different cell lines.

Basement Membrane↗
PubMed1987

Screening for colorectal cancer in a high-risk population. Results of a mathematical model.

A mathematical model was used to estimate the cost-effectiveness of colorectal cancer screening strategies for people who are at high risk because of a first-degree relative with colorectal cancer. The model uses indirect evidence about such factors as cancer incidence, sensitivity and specificity of different tests, and treatment effectiveness. The analysis indicates that for screening people over 40 yr old an annual fecal occult blood test may reduce colorectal cancer mortality by about one-third, either colonoscopy or barium enema may reduce mortality by approximately 85%, a 3-5-yr frequency for endoscopies or barium enemas preserves 70%-90% of the effectiveness of an annual frequency, and beginning screening at age 50 reduces effectiveness by 5%-10%. Although both barium enemas and colonoscopies appear to be effective in reducing mortality, the lower cost of the barium enema makes it a more cost-effective strategy. All of these estimates depend on the baseline estimates of each of the factors incorporated in the model; the conclusions are most sensitive to assumptions about the natural history of adenomatous polyps, the bleeding of adenomas and presymptomatic cancers, and the sensitivity of the fecal occult blood test. Recommendations about colorectal cancer screening must also consider factors such as discomfort, inconvenience, and the availability of various technologies.

Colonic Neoplasms↗
PubMed1987

Proliferation of esophageal epithelial cells among residents of Linxian, People's Republic of China.

Histopathologic and tritiated thymidine labeling subjects were carried out on esophageal biopsy specimens of 44 human subjects with cytologic evidence of dysplasia from Linxian, People's Republic of China, a high-risk area for esophageal cancer. With the use of histopathologic criteria, 10 cases showed evidence of dysplasia, 20 hyperplasia, and 14 a near-normal morphology when compared with 21 normal cases studied previously from Jiaoxian, a low-risk area for esophageal cancer in the People's Republic of China. Significantly increased labeling indices were found in the esophageal mucosa of the dysplasia and hyperplasia subjects. There was a gradient of increased expansion in the basal layer of proliferating cells progressing from normal to hyperplasia to dysplasia, with the expansion twice as high in the epithelial cell lining in dysplasia when compared with the findings in the normal and near-normal groups. The correlation of proliferative abnormalities with the severity of precancerous lesions of the esophagus indicates that labeling studies may provide a sensitive adjunct to evaluate risk status and any modifications that might result from nutritional intervention.

Biopsy↗
PubMed1986

Inhibition of human colonic epithelial cell proliferation in vivo and in vitro by calcium.

Nine patients at high risk of developing colon cancer were placed on daily p.o. supplementation of 1500 mg of calcium for 4-8 weeks. The colonic epithelial cells in six of these patients showed a statistically significant decrease in their [3H]thymidine labeling indices in tissue culture so that they resembled those of patients at low risk of developing colon cancer. The three nonresponders had similar labeling indices before and after calcium supplementation. Biopsies from each of nine high-risk patients exhibited a decrease in proliferation when they were cultured in vitro with a high level of CaCl2 (2.2 mM compared with the 0.1 mM optimum value for proliferation). Two adenomas and two carcinomas showed a different pattern of response than normal cells, exhibiting no inhibition of growth at 2.2 mM CaCl2. These data indicate that the growth inhibition induced by high levels of extracellular calcium levels is lost at a stage in tumor development before cells become malignant.

Calcium, Dietary↗
PubMed1985

Seventh-Day Adventist vegetarians have a quiescent proliferative activity in colonic mucosa.

The proliferation of epithelial cells in colonic mucosa was studied in humans at varying degrees of risk for colon cancer. Seventh-Day Adventist vegetarians, known to have significantly lower mortality from colon cancer than the general U.S. population, had the most quiescent proliferative activity of mucosal epithelial cells. Increased replication and expansion of the proliferative compartment accompanied increased colon cancer risk. The analytical methods of this study may be useful in assessing the influence of dietary components involved in the initiation, promotion or inhibition of colon cancer, and in developing strategies for nutritional intervention.

Adult↗
PubMed1984

A model for human colon carcinoma evolution based on the differential response of cultured preneoplastic, premalignant, and malignant cells to 12-O-tetradecanoylphorbol-13-acetate.

Small colonic adenocarcinomas can be found in focal areas within benign tumors (adenomas), strongly suggesting an adenoma-to-carcinoma sequence. The induction of plasminogen activator (PA) secretion by the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) has been used to order histologically distinct classes of human colonic adenomas in primary culture into a sequence from the most benign to the most advanced premalignant state. This ordering is based on the observation that each of five carcinomas examined in an earlier study by E. A. Friedman (Cancer Res., 41: 4588-4599, 1981) and each of seven carcinomas tested in this study released PA in response to TPA, inducing easily scored morphological alterations. Benign tumors either resembled carcinomas in their response to TPA or exhibited no morphological changes. The most benign adenomas by histopathology criteria were the small pure tubular adenomas without dysplasia. Six of seven of these adenomas did not secrete PA in response to TPA. We concluded that malignant cells had acquired the ability to respond to TPA by PA secretion, while tubular adenoma cells were not an advanced enough preneoplastic stage to so respond. TPA treatment of two cultured villous adenomas, one with infiltrating carcinoma and one with focus of moderately dysplastic cells, in the presence of low serum to decrease the plasmin concentration, demonstrated that only a subpopulation of cells secreted PA. Local areas of the monolayer were morphologically altered by the protease, forming clusters of cells loosely attached to the dish. The presence of such subpopulations within cultured adenomas was demonstrated by screening an additional five villous adenomas, 15 villotubular adenomas, and 11 tubular adenomas. The presence of dysplastic cells in 23 of 24 cases correlated with PA secretion. A subpopulation of villous cells, in the absence of dysplastic cells in each of three cases, also secreted PA. We conclude that, during tumor evolution, this villous subpopulation is the first preneoplastic cell type to acquire responsiveness to TPA by PA secretion. This property is maintained as the cells further evolve through premalignant dysplastic stages to carcinoma.

Adenoma↗
PubMed1984

Actin cytoskeletal organization loss in the benign-to-malignant tumor transition in cultured human colonic epithelial cells.

The colonic epithelium in vivo is a highly indented sheet one cell thick. Culture methods have been developed to allow the normal cellular migration of the cells comprising this sheet to flatten it into a patch on the surface of a Petri dish [Friedman, E. A., Higgins, P.J., Lipkin , M., Shinya , H., and Gelb , A.M., In Vitro (Rockville), 17: 632-644, 1981]. Actin cytoskeletal organization was analyzed in such epithelial "patches" derived from several human colonic adenocarcinomas and their precursors, adenomas (benign tumors). The actin cytoskeleton was visualized by fluorescence microscopy after the fixed, permeabilized cells were stained with rhodamine-conjugated phalloidin. This drug has a very high affinity for actin filaments and a much lower affinity for monomeric actin. Actin organization was scored from 0 (no cables) to 5 points (extensive intercellular cable network). The phalloidin-stained actin found in seven adenocarcinomas had a predominantly granular fluorescence pattern with very little cable organization, scoring an average of 0.9 +/- 0.8 (S. D.). Three established cell lines derived from human colon carcinomas contained no cables by this analysis, scoring 0.0 +/- 0.0. In marked contrast, all 12 of the cultured adenomas had extensive actin cable networks, scoring an average of 4.3 +/- 0.4. There was no statistical difference between adenomas of differing histopathology class and malignant potential. However, cytoskeletons of plasminogen-activator-secreting "late-stage" preneoplastic cells from adenomas became disorganized by exposure to 12-O-tetradecanoyl-phorbol-13-acetate or another tumor promoter, teleocidin B. They scored, respectively, average actin organization values of 0.0 +/- 0.0 and 0.4 +/- 0.6. In contrast, nonplasminogen -activator- secreting "early-stage" preneoplastic cells from less advanced benign tumors were unaffected by 12-O-tetradecanoyl-phorbol-13- acetate or teleocidin B and retained extensive actin organization. Most, if not all, adenocarcinomas arise from preexisting preneoplastic adenomatous cells. Thus, loss of actin organization appears to mark the transition of noninvasive benign colonic tumors to invasive malignant tumors in humans. This transition is mimicked in vitro by exposure of certain "late-stage" preneoplastic cells to a tumor promoter which induces secretion of a plasminogen activator.

Actins↗
PubMed1984

Classification and risk assessment of individuals with familial polyposis, Gardner's syndrome, and familial non-polyposis colon cancer from [3H]thymidine labeling patterns in colonic epithelial cells.

A probabilistic analysis has been developed to assist the binary classification and risk assessment of members of familial colon cancer kindreds. The analysis is based on the microautoradiographic observation of [3H]thymidine-labeled epithelial cells in colonic mucosa of the kindred members. From biopsies of colonic mucosa which are labeled with [3H]thymidine in vitro, the degree of similarity of each subject's cell-labeling pattern measured over entire crypts was automatically compared to the labeling patterns of high-risk and low-risk reference populations. Each individual was then presumptively classified and assigned to one of the reference populations, and a degree of risk for the classification was provided. In carrying out the analysis, a linear score was calculated for each individual relative to each of the reference populations, and the classification was based on the polarity of the score difference; the degree of risk was then quantitated from the magnitude of the score difference. When the method was applied to kindreds having either familial polyposis or familial non-polyposis colon cancer, it effectively segregated individuals affected with disease from others at low risk, with sensitivity and specificity ranging from 71 to 92%. Further application of the method to asymptomatic family members believed to be at 50% risk on the basis of pedigree evaluation revealed a biomodal distribution to nearly zero or full risk. The accuracy and simplicity of this approach and its capability of revealing early stages of abnormal colonic epithelial cell development indicate potential for preclinical screening of subjects at risk in cancer-prone kindreds and for assisting the analysis of modes of inheritance.

Colonic Neoplasms↗
PubMedDate not supplied

High levels of transforming growth factor beta 1 correlate with disease progression in human colon cancer.

Several genes have identified that play a role in colon cancer development. However, less is known about factors that increase the rate of progression of colon cancers to metastasis. One candidate is transforming growth factor beta 1 (TGF beta 1), which can enhance the aggressiveness of human colorectal cell lines in vitro and in vivo. The amount of TGF beta 1, TGF beta 2, and TGF beta 3 protein isoforms expressed in primary site colorectal cancers were measured to determine whether any correlation existed between protein levels and disease recurrence in a series of Memorial Sloan-Kettering Hospital patients who underwent potentially curative resections. Intense staining for TGF beta 1 correlated significantly (P < 0.0013; odds ratio, 18) with disease progression to metastasis and was independent of nodal status and the degree of differentiation of the primary tumor. Therefore, in this study, patients with high TGF beta 1 protein levels in their primary site colorectal cancer were 18 times more likely to experience recurrence of their disease than were patients whose tumors exhibited low levels of TGF beta 1. In this case-control study, patients whose cancer recurred and those remaining cancer free were age and sex matched. The disease recurred at a mean of 26.8 +/- 4.3 (SE) months, whereas the mean follow-up time in patients whose disease did not recur was over twice as long, 57.3 +/- 6.6 months. Ninety-four % of the patients in each group were node positive at the time of resection, with equal mean numbers of positive nodes per patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗