Well-differentiated Cancer Cells Research Articles

Differential responses of scirrhous and well-differentiated gastric cancer cells to orthotopic fibroblasts.

Scirrhous gastric cancer cells proliferate rapidly with fibrosis, when the cancer cells invade into the submucosa of the stomach. To investigate the mechanisms responsible for the rapid proliferation, the growth interaction between gastric cancer cells and fibroblasts was examined. Human gastric cancer cell lines established from scirrhous carcinoma or well-differentiated adenocarcinoma were used. Human fibroblast cell lines were obtained from various organs. The growth interaction between gastric cancer cells and fibroblasts was examined by calculating the number of cancer cells or by measuring [3H]thymidine incorporation of cancer cells. Gastric fibroblasts specifically stimulated the growth of scirrhous gastric cancer cells, but not that of well-differentiated adenocarcinoma cells. The growth factor(s) produced from gastric fibroblasts were then partially purified and characterised. The growth-promoting factor(s) had apparent molecular weights of 10000 dalton and was sensitive both to heat and proteinase treatment. No inhibition for the factor(s) was achieved with defined anti-growth factor antibodies. In this study, differential responses of scirrhous and well-differentiated gastric cancer cells to orthotopic fibroblasts were shown. Rapid proliferation of scirrhous gastric carcinoma should be partly controlled by orthotopic fibroblasts. The growth factor(s) from gastric fibroblasts, which was distinct from various defined growth factors such as epidermal growth factor (EGF), basic fibroblast growth factor (b-FGF), transforming growth factor-alpha (TGF-alpha), keratinocyte growth factor (KGF), vascular endothelial growth factor (VEGF), insulin-like growth factor I (IGF-I), hepatocyte growth factor (HGF), platelet-derived growth factor (PDGF) and transforming growth factor beta 1 (TGF-beta 1) may play an important role in the progression of scirrhous gastric cancer cells.

Immunocytochemical detection of p53 in human thyroid carcinomas is associated with mutation and immortalization of cell lines.

Mutations in the tumor suppressor gene p53 are the most-common mutations found in human cancers. In thyroid cancers, p53 mutations generally are found only in poorly differentiated and undifferentiated tumors and in cell lines. To determine the prevalence of p53 mutations in thyroid neoplasms and thyroid cell lines, we screened 58 thyroid tissues and 3 thyroid cell lines, p53 primers bracketing exons 4, 5/6, 7, and 8 were used to amplify genomic DNA using the PCR. Mutations were screened by denaturing gradient gel electrophoresis and confirmed by sequencing. The two papillary thyroid cancer cell lines and the follicular thyroid carcinoma cell line (positive control) had transitions (CGT->CAT) in exon 8, codon 273, resulting in the replacement of arginine with histidine. No normal thyroid tissues or primary tumors from which the cell lines were derived demonstrated exon 8 mutations, using this technique. p53 immunocytochemistry demonstrated a progression of p53 immunopositivity between synchronous and metachronous neoplasms, paralleling the neoplastic progression from a benign adenoma to primary carcinoma, regional, and distant metastasis and ultimately, the cell lines, where intense immunopositivity is noted. In addition, fluorescence in situ hybridization, using probes specific for the p53 locus, revealed the presence of 3 homologues of p53 in the follicular cell line and 2 homologues in the papillary and Hürthle cell lines. These results suggest that a point mutation present in a small number of original tumor cells and amplification of the mutant allele may be responsible for immortalizing well-differentiated thyroid cancer cells into cell lines.

Accumulation of 5-Aminolevulinic Acid-Induced Protoporphyrin IX in Normal and Neoplastic Human Endometrial Epithelial Cells

The aim of this study was to evaluate 5-Aminolevulinic acid (ALA)-induced fluorescence of normal and neoplastic endometrial epithelial cells for diagnosis and photodynamic treatment. Fluorescence of ALA-induced PpIX in vitro was measured by flow cytometry in two different human endometrial adenocarcinoma cell lines and in normal cells cultivated from fresh endometrial tissue of three premenopausal patients. The cells were analysed after incubation with different concentrations of ALA during 3, 6, or 24 hours. Both tumor cell lines showed a statistically significant higher fluorescence of PpIX than normal epithelial cells after incubation with 1 mg ALA per ml medium during 24 hours. The well-differentiated cancer cells produced significantly more PpIX than the poorly differentiated cancer cells. Relative PpIX intensity of the two cancer cell lines correlated with cell proliferation rate as measured by the doubling times of the cells. Higher accumulation of Pp IX in neoplastic endometrium compared to normal endometrial epithelial cells may provide targeted biopsies and selective photodynamic destruction of neoplastic micro-lesions.

Transfecting Well-Differentiated Prostatic Cancer Cell Line LNCaP

The transfection of well-differentiated sensitive cells requires careful optimization of the conditions used. In addition to the transfection method chosen, the amount of cells plated, and thus the density of the cells, as well as the influence of the serum concentration play a critical role in the case of LNCaP cells. We also found out that the only appropriate control plasmid for the transfection efficiency was pCMVβ-gal driven by the cytomegalovirus promoter.

Biphasic effects of thyrotropin on invasion and growth of papillary and follicular thyroid cancer in vitro.

The rationale for TSH suppression in the treatment of follicular thyroid cancer (FTC) and papillary thyroid cancer (PTC) is to inhibit tumor growth, prevent recurrent disease, and eventually prolong survival. We analyzed the effects of TSH on invasion and growth of 3 FTC cell lines from 1 patient (FTC133, primary; FTC236, lymph node; FTC238, lung metastasis) and 2 PTC cell lines (PTC-UC1, PTC-UC3). Cell growth and invasion through an 8-micron pore polycarbonate membrane coated with Matrigel were measured using the MTT assay. The dose-response to TSH was biphasic, stimulating invasion and growth of FTC and PTC at low concentrations (0.1-10 mU/mL), and inhibiting them at high concentrations (100 mU/mL). Interestingly, the metastatic FTC cell lines had higher basal invasion, but were less responsive to TSH than the primary tumor. TSH (1 mU/mL) stimulated invasion of FTC133 by 21%, FTC236 by 8%, and FTC238 by 8% (p < 0.01). At 100 mU/mL, TSH inhibited invasion of FTC133 by 21%, compared to 11% in FTC236 and 12% in FTC238. Also, TSH dose-dependently influenced proliferation of follicular thyroid cancer cells. At low concentrations it stimulated growth of FTC133 (20%) and inhibited it at high concentrations (23%; p < 0.01). Again, the amplitude of TSH effects was significantly smaller in the cell lines from metastatic tumors. TSH affected invasion and growth of PTC-UC1 and PTC-UC3 also biphasically. These results show that TSH may act as a mitogenic and antimitogenic growth factor for invasion and proliferation of well-differentiated thyroid cancer cells in vitro.

Immunocytochemical localization of fibroblast growth factor-1 (FGF-1) and FGF-2 in oral squamous cell carcinoma (SCC).

The localization of fibroblast growth factor-1 (FGF-1) and FGF-2 in human oral squamous cell carcinoma (SCC) was examined by immunohistochemical techniques using anti-FGF-1 and anti-FGF-2 monoclonal antibodies. Immunofluorescence staining of two oral SCC cell lines revealed that growing cancer cells were intensely positive for both FGF-1 and FGF-2, but confluent cells showed a faint immunostaining. In addition, two molecular mass species of FGF-1 (16 and 18 kDa) and one of FGF-2 (18 kDa) were identified by Western blot in cell extracts derived from growing SCC cells, but not from confluent SCC cells. The growing cell extracts significantly stimulated the proliferation of human umbilical vein endothelial cells. Immunoperoxidase staining of 13 oral SCC cases showed that both well-differentiated and poorly-differentiated cancer cells were positive for FGF-1 and FGF-2 with high frequency and intensity as compared to normal oral epithelium. These results indicate that SCC cells express high levels of endogenous FGF-1 and FGF-2, and suggest that these growth factors may contribute to cancer cell growth.

Natural killer cell lysis of head and neck cancer.

This study analyzed the capacity of both fresh unseparated peripheral blood lymphocytes and enriched natural killer (NK) cells to lyse head and neck cancer cell lines. In a 6-hour chromium-release assay, only Leu-19+ NK cells mediated significant lysis. Furthermore, cell lines established from poorly differentiated cancers were more sensitive to lysis than were cell lines established from well-differentiated cancers. Cell lines from well-differentiated cancers also less readily inhibited K562 lysis in a cold-target inhibition assay, were not recognized by NK cells in a monolayer absorption assay (unlike poorly differentiated cancers), and failed to form conjugates with NK cells in a single-cell assay. These results indicated that deficient killing of a well-differentiated cancer cell vs a poorly differentiated cancer cell is partly a function of diminished NK cell recognition and tumor binding necessary to initiate lysis. As in previous studies regarding the prognostic implication of quantitated measures of NK cell activity within head and neck cancer patients, the results support the biologic relevance of the NK cell as a defense mechanism against metastatic disease, especially in patients with poorly differentiated, low major histocompatibility complex class I-expressing head and neck cancers.

Implications of hyperechoic lesions in small hepatocellular carcinoma

Of 34 solitary small hepatocellular carcinomas (HCC) 2 cm in diameter or less, 13 with hyperechoic lesions were observed serially by sonography, and 11 of these were examined histologically. Serial examination showed that hypoechoic areas appeared at the periphery of or within, the hyperechoic tumor, and that these areas expanded more with tumor growth than the hyperechoic areas as if compressing or displacing the existing hyperechoic areas. Histologically, the hyperechoic lesions were composed mostly of well-differentiated cancer cells containing fat droplets, whereas the hypoechoic lesions were composed of cancer cells without fat droplets. In the two tumors that were formed almost completely of cancer cells showing fatty metamorphosis, cancer cells without fat droplets proliferated mainly in the periphery of the tumor. These findings suggest that, in hyperechoic HCC, cancer cells with fat droplets appear in the early stage of HCC, and probably change into concer cells without fat droplets by the time that a certain tumor size is reached, with gradual displacement by the latter type of cell during tumor growth.

Use of cytogenetic analysis of body fluids in cancer diagnosis.

Direct chromosome preparations were made from 52 malignant and 21 non-malignant effusions. An effusion was classified as malignant if 2% of the counted cells showed abnormal karyotypes. There was a significant relationship between diversified karyotypes and the pathological nature of tumours: diversity of karyotypes was much higher in undifferentiated adenocarcinoma, anaplastic carcinoma and embryonal cell carcinoma cells than in well-differentiated cancer cells. Diagnosis was positive for 38 of the 52 malignant effusions by cytological examination (73% sensitivity), and positive for 41 of the 52 by cytogenetic analysis (78% sensitivity). There were no false positive results using both cytogenetic and cytologic examinations (92% sensitivity). Particularly in patients with equivocal cytology, cytogenetic analysis appears to be a useful tool in the diagnosis of malignant effusions.

Correlations of the receptor content and ultrastructure of breast cancer cells.

Receptor assay results were compared with the ultrastructure of 127 breast cancers (112 primary tumors, six recurrent lesions, nine metastases). Tumors were considered to be receptor positive if the receptor levels were greater than or equal to 15 fmol/mg of soluble tissue protein. Most breast cancer had heterogenous cells with different grades of ultrastructural differentiation. a prevalence of well-differentiated cancer cells and an abundance of intracytoplasmic vacuoles had a significant correlation with a positive estrogen receptor status. The correlation was better than between malignancy grades and receptor content. The type of breast cancer and the menopausal status bore no relation to receptor content. Progesterone receptors were found in well-differentiated tumors of low malignancy.