Apoptosis induced by progesterone in human ovarian cancer cell line SNU-840

Progesterone has been used as an ingredient of anticancer drug for patients with ovarian carcinoma. However, the mechanism of anticancer effects by progesterone has not been understood. In this study, the effects of progesterone on ovarian cancer cells, SNU-840, were investigated. After the incubation with progesterone, the viability of the cells was evaluated by MTT assay. As a result, 45% of the cells were viable after 48 h of incubation with 100 microM progesterone. In addition, [(3)H]thymidine incorporation assay showed that the proliferation of the cells was completely inhibited by progesterone after 48 h of incubation at 100 microM concentration. Colorimetric TUNEL assay revealed the fragmentation of the chromosomal DNA, suggesting that the process of the cell death was apoptosis. The level of the p53 mRNA was determined by northern blotting assay, since many apoptosis processes are mediated by up-regulation of the p53 expression. The level of the p53 mRNA reached its maximum at 12 h and decreased after 24 h of incubation with progesterone. In conclusion, progesterone inhibits the proliferation and elicits apoptosis of SNU-840 cells. Also, it up-regulates the p53 mRNA transiently.     

Activation of N-ras in a human melanoma cell line.

DNA isolated from cell line Mel Swift, a human melanoma cell line, transforms NIH3T3 cells. Southern blot analysis of DNA from secondary foci revealed conserved 8.8- and 7.8-kilobase EcoRI fragments which hybridized with a human repetitive sequence clone, blur 8. The activated transforming gene was identified as N-ras, and the 8.8-kilobase EcoRI fragment from a secondary transformant was cloned. Synthetic 17-mer oligonucleotides which spanned either the normal codon 61 (CAA) or a mutant codon 61 (AAA) were used for hybridization. Cloned N-ras from melanoma cell line Mel Swift hybridized to the mutant (AAA) oligonucleotide. From this we predicted a glutamine-to-lysine substitution in amino acid 61, a change confirmed by conventional sequencing of the first and second exons of N-ras from cell line Mel Swift. Transfection experiments showed that only those recombinant clones with the mutation in position 61 were biologically active.     

Apoptosis and cell cycle arrest of human colorectal cancer cell line HT-29 induced by vanillin

Background: Vanillin is responsible for the flavor and smell of vanilla, a widely used flavoring agent. Previous studies showed that vanillin could enhance the repair of mutations and thus function as an anti-mutagen. However, its role in cancer, a disease that is closely related to mutation has not yet been fully elucidated. Methods: Hence, this study investigated the cytolytic and cytostatic properties of vanillin against HT-29, a human colorectal cancer cell line. Methods used including cell viability assay, acridine orange (AO)–ethidium bromide (EB) double staining cell morphological analysis, Cell cycle analysis, annexin V–propidium iodide apoptosis test and 5-bromo-2-deoxyuridine (BrdU)-labeling cell proliferation assay. Results: Results showed that apoptosis was induced by vanillin and the IC₅₀ for HT-29 and NIH/3T3 normal cell lines were 400 μg/ml and 1000 μg/ml, respectively. Different concentrations of vanillin arrest cell cycle at different checkpoints. 5-Bromo-2-deoxyuridine-labeling cell proliferation assay showed that G0/G1 arrest was achieved at lower concentration of vanillin (200 μg/ml) while cell cycle analysis by flow cytometer showed that G2/M arrest occurs at higher concentration of vanillin (1000 μg/ml). Conclusion: Cytolytic and cytostatic effects shown by vanillin showed that it could be a useful colorectal cancer preventive agent. Further in vivo study should be carried out to confirm that similar effects could happen in animals.     

A human hepatoma cell line expresses a single-chain form of gamma-glutamyl transpeptidase

Mammalian gamma-glutamyl transpeptidases characterized thus far have been shown to be heterodimeric glycoproteins. The two subunits are derived from a single-chain propeptide which, in the rat kidney, exhibits low transpeptidase activity (less than 2% of the dimeric enzyme). A human hepatoma-derived cell line, Hep G2, expresses relatively high transpeptidase activity. The enzyme is primarily localized on the cell surface and exhibits catalytic properties similar to the dimeric human kidney and lymphoid cell transpeptidase. Significantly, the Hep G2 enzyme, unlike the enzyme from other human tissues, is a single-chain species, Mr = 120,000.     

Bowes human melanoma cell line. An immunocytochemical study

Bowes human melanoma cell line was investigated immunocytochemically to localize S-100 protein, HMB-45 and intermediate filament proteins. The majority of the cells showed strong positive staining with antibodies directed against S-100 protein, HMB-45 and vimentin filaments. Antibodies directed against the other cytoskeletal proteins failed to show any reactivity. These findings suggest that this transformed cell line does not dedifferentiate in culture and continues to express the specific antigens of human melanoma cells. Thus, Bowes cell line provides a useful model for studying the cellular biology and pathology of malignant melanoma.     

Apoptosis induced by selenium in human glioma cell lines

Several studies have shown that selenium can inhibit tumorigenesis in tissues. However, little is known about the mechanism and the effect of selenium on DNA, especially in brain tumor cells. In this study we examined the biological effect of selenium on human glioma cell lines (A172 and T98G). Selenium exhibited an antiproliferative effect on these cell lines (and induced the typical ladder pattern of DNA fragmentation commonly found in apoptosis), which were prevented by catalase. Few effects of selenium on NTI4 fibroblasts were found. These findings demonstrate that selenium may induce, by apoptosis, cell death of human glioma cell lines, which are resulting from free radical oxygen forming.     

Selective growth inhibition of a human malignant melanoma cell line by sesame oil in vitro.

Ayurveda, an ancient and comprehensive system of natural medicine, recommends regular topical application to the skin of sesame oil, above all other oils, as a health-promoting procedure. We examined the effect of sesame oil and several other vegetable oils and their major component fatty acids on the proliferation rate of human normal and malignant melanocytes growing at similar rates in serum-free media. We found that sesame and safflower oils, both of which contain large amounts of linoleate in triglyceride form, selectively inhibited malignant melanoma growth over normal melanocytes whereas coconut, olive and mineral oils, which contain little or no linoleate as triglyceride, did not. These oils were tested at a range of 10-300 micrograms/ml. We found that of the fatty acids tested, only linoleic acid was selectively inhibitory while palmitic and oleic were not. These fatty acids were tested in the range of 3-100 micrograms/ml. These results suggest that certain vegetable oils rich in linoleic acid, such as the sesame oil, recommended for topical use by Ayurveda, may contain selective antineoplastic properties which are similar to those demonstrated for essential polyunsaturated fatty acids and their metabolites. This suggests that whole vegetable oils may have potential clinical usefulness.     

Apoptosis induced by sodium butyrate treatment increases immunogenicity of a rat colon tumor cell line

We have recently demonstrated that a treatment combining the cell differentiating agent sodium butyrate (NaBut) and interleukin-2 (IL2) resulted in a remission of established peritoneal colorectal carcinomatosis in rats. NaBut or IL2 treatment alone, never cured these tumour-bearing rats. In the present investigation, we report that NaBut-treatments induce apoptosis in the colonic cancer cells both in vitro and in vivo. We postulated that the significant therapeutic effect of NaBut/IL2 treatment can be mainly attributed to a NaBut-induced apoptosis of the tumoural cells increasing their immunogenicity. Indeed, treatment which combined apoptotic bodies (apobodies) as cell vaccine, plus IL2 immunotherapy significantly increased tumour remission and survival rate of the vaccinated rats, whereas IL2 treatment alone did not. We observed that the cured rats presented long-term protection against subsequent challenge with the parental tumour cells. This latter result suggests that these treatments generate an immune protection. This was confirmed by the presence, in the sera of the cured rats, of anti-tumoural antibodies directed against both the apobodies and the tumour cells, but not against normal colonocytes. In addition, we show that injections of apobodies before administration of the parental tumour cells results in a partial protection. We provide the first evidence that apobodies, derived from cancer cells after NaBut-treatment, induce a specific immune response against parental tumours cells. These data suggest that the distinctive immunologic properties of apobodies could provide a valuable tool in colorectal cancer immunotherapy.     

Retargeting of human regulatory T cells by single-chain bispecific antibodies

Bispecific Abs hold great potential for immunotherapy of malignant diseases. Because the first components of this new drug class are now entering clinical trials, all aspects of their mode of action should be well understood. Several studies proved that CD8(+) and CD4(+) effector T cells can be successfully redirected and activated against tumor cells by bispecific Abs both in vitro and in vivo. To our knowledge, this study provides the first evidence that bispecific Abs can also redirect and activate regulatory T cells against a surface Ag, independently of their TCR specificity. After cross-linking, via a bispecific Ab, redirected regulatory T cells upregulate the activation markers CD69 and CD25, as well as regulatory T cell-associated markers, like CTLA-4 and FOXP3. The activated regulatory T cells secrete the immunosuppressive cytokine IL-10, but, in contrast to CD8(+) and CD4(+) effector T cells, almost no inflammatory cytokines. In addition, the redirected regulatory T cells are able to suppress effector functions of activated autologous CD4(+) T cells both in vitro and in vivo. Therefore, the potential risk for activation of regulatory T cells should be taken into consideration when bispecific Abs are applied for the treatment of malignant diseases. In contrast, an Ag/tissue-specific redirection of regulatory T cells with bispecific Abs holds great potential for the treatment of autoimmune diseases and graft rejection.     

Apoptosis induced by butyrate is independent of Jak/STAT signaling in a fibrosarcoma cell line

The aim of this study was to evaluate the participation of the Jak-1 and STAT-1 proteins in sodium butyrate-induced apoptosis in 2C4 cells derived from human fibrosarcoma. Making use of Jak-1 or STAT-1 deficient cell lines, we demonstrated that the apoptotic process induced by butyrate is independent of the presence of these proteins. In addition, this work showed that, although the constitutive expression of pro-caspases-2 and -3 is reduced in STAT-1 cells, the activity of caspase-3 is preserved in both Jak-1 and STAT-1 deficient cells and is similar to that seen in 2C4 parental cells. In conclusion, we demonstrated that the absence of functionally active Jak-1 or STAT-1 protein directly affects the TNF-alpha-induced apoptosis, but does not alter the sodium butyrate-induced apoptosis in cells derived from human fibrosarcoma.     

Reversible macrophage differentiation induced in a new human myeloid cell line by gamma interferon.

A new cell line was established from the bone marrow of a patient with chronic myeloid leukemia. The cells were attributed an intermediate myeloid phenotype on the basis of their cytochemical features and membrane antigen expression. These cells respond to both chemical and physiological activators of the signal transduction pathways with growth arrest and phenotype changes. Macrophage maturation can be induced in a fraction of the cells by gamma-interferon (γ-IFN). Cells are however recruited again into the cell cycle by recultivation in γ-IFN-free medium: variants unresponsive to γ-IFN, and others which show either reversible or irreversible differentiation were isolated from the original cell line by cloning and sib-selection. These clones can be used to investigate the relationship between γ-IFN response pathways and cell proliferation.     

Proteomic profiling of human melanoma metastatic cell line secretomes

During the last few years, the incidence and mortality of human melanoma have rapidly increased. Metastatic spread of malignant melanoma is often associated with cancer progression with poor prognosis and survival. These processes are controlled by dynamic interactions between tumor melanocytes and neighboring stromal cells, whose deregulation leads to the acquisition of cell proliferation capabilities and invasiveness. It is increasingly clear that a key role in carcinogenesis is played by secreted molecules either by tumor and surrounding stromal cells. To address the issue of the proteins secreted during cancer progression, the proteomic profiling of secretomes of cancer cell lines from different melanoma metastases of the same patient (PE-MEL-41, PE-MEL-47, and PE-MEL-43) was performed by applying a shotgun LC-MS/MS-based approach. The results provide a list of candidate proteins associated with the metastatic potential of PE-MEL melanoma cell lines. Among them, several matricellular proteins previously reported as involved in melanoma aggressiveness were identified (i.e., SPARC, osteopontin). In addition, the extracellular matrix protein 1 that stimulates proliferation and angiogenesis of endothelial cells as well as the fibronectin, involved in cell adhesion and motility, were identified. The present work provides the basis to clarify the complex extracellular protein networks implicated in human melanoma cell invasion, migration, and motility.     

A cell membrane alteration specifically induced by SV40 transformation.

Transformation of mouse 3T3 cells by SV40 results in a specific membrane modification which renders cells resistant to the killing action of the lipophilic antibiotic Amphotericin B. This alteration is under genetic cellular control and is specific for SV40 transformation since transformation with polyoma or mouse sarcoma viruses does not confer resistance to the antibiotic. Analogous resistance is induced by SV40 transformation of primary human fibroblast cells. The acquired resistance is not due to decreased binding of Amphotericin B and is partially reversed if cells are grown in the presence of cholesterol. The results are interpreted as a specific change of sterol structure of the membrane or the loss of a minor cholesterol fraction responsible for the killing action of the antibiotic.     

Characterization of a new human melanoma cell line with CD133 expression

A novel human malignant melanoma cell line, designated MEL-RC08, was established from a pericranial metastasis of a malignant melanoma of the skin. The cell line has been subcultured for more than 150 passages and is tumorigenic in nude mice. Growth kinetics, cytogenetics, flow cytometry, and molecular techniques for analysis of the genes implicated in cell cycle control; mutations in BRAF, NRAS, C-KiT, RB, and TP53 genes; and amplification of MDM2, CDK4, and cyclin D1 have been studied. Cytogenetically, the tumor and the cell line showed a hypertriploid karyotype with many clonal numeric and structural abnormalities. DNA flow cytometry showed an aneuploid peak with a DNA index value of 1.5. Mutations in TP53 and BRAF genes were demonstrated in both tumor and cell line. Furthermore, stem cell marker CD133 expression was detected in most cells, together with other stem cell markers, suggesting the presence of cells with tumor-initiating potential in this cell line.