Carcinogenesis

https://academic.oup.com/carcin

List of Papers (Total 1,106)

Effects of particle exposure and particle-elicited inflammatory cells on mutation in rat alveolar epithelial cells.

To investigate mechanisms underlying development of lung adenomas and carcinomas in rats exposed to poorly soluble particles the relationships between particle exposure, inflammation and mutagenesis in rat alveolar type II cells were characterized. Rats were exposed to saline or saline suspensions of 10 and 100 mg/kg of alpha-quartz, carbon black or titanium dioxide by...

Benzo[a]pyrene and its analogues: structural studies of molecular strain.

The molecular geometry of benzo[a]pyrene, its 4-methyl-and 3,11-dimethyl derivatives, benzo[e]pyrene, and two azabenzo[a]pyrenes are described. Results of these three-dimensional crystal structure determinations, together with those from previous studies in this laboratory of 11-methylbenzo[a]pyrene, indicate the extent to which nonbonded interactions between hydrogen atoms...

A processive versus a distributive mechanism of action correlates with differences in ability of normal and xeroderma pigmentosum group A endonucleases to incise damaged nucleosomal DNA.

A DNA endonuclease, isolated from the nuclei of normal human and xeroderma pigmentosum complementation group A (XPA) cells, which recognizes predominately pyrimidine dimers, was examined for the mechanism by which it locates sites of damage on UVC-irradiated DNA. In reaction mixtures with low ionic strengths (i.e. lacking KCl), the normal and XPA endonuclease locate sites of UV...

Fibroblasts transformed by chemical carcinogens are sensitive to intercellular induction of apoptosis: implications for the control of oncogenesis.

The ability of neighbouring normal cells to inhibit proliferation of transformed cells is regarded as the classical mode of intercellular control of potential tumour cells. This mechanism, however, only controls the pool size of transformed cells, but does not impair their survival. We have recently shown that cells transformed by biological agents are subject to a novel control...

Bcl-2 deregulation leads to inhibition of sodium butyrate-induced apoptosis in human colorectal carcinoma cells.

Epidemiological studies have linked dietary fiber to the prevention of human colorectal cancer and suggest that short chain fatty acids such as butyric acid, which is produced by fermentation of dietary fiber in the large intestine, may be an important mediator of the protective effects of fiber. We investigated the role of Bcl-2 deregulation on the sensitivity of colorectal...

Selective elimination of human lymphoid cells with unstable chromosome aberrations by p53-dependent apoptosis.

Alterations in p53 expression are associated with genomic instability, presumably because loss of p53 leads to an inability to eliminate damaged and therefore potentially unstable cells by apoptosis or by induced cell cycle block. We tested this hypothesis by examining the influence of apoptosis on X-ray-induced chromosome aberration frequency in two isogenic human B...

Avoided and avoidable risks of cancer.

Despite the considerable efforts and funds devoted to cancer research over several decades, cancer still remains a mainly lethal disease. Cancer incidence and mortality have not declined at the same rate as other major causes of death, indicating that primary prevention remains a most valuable approach to decrease mortality. There is general agreement that environmental exposures...

Hydrogen peroxide inhibits gap junctional intercellular communication in glutathione sufficient but not glutathione deficient cells.

Cell to cell communication via gap junctions is essential in the maintenance of the homeostatic balance of multicellular organisms. Aberrant intercellular gap junctional communication (GJIC) has been implicated in tumor promotion, neuropathy and teratogenesis. Oxidative stress has also been implicated in similar pathologies such as cancer. We report a potential link between...

SHORT COMMUNICATION: Negative interference of metal (II) ions with nucleotide excision repair in human cell-free extracts

Inhibition of the nucleotide excision repair (NER) proces is believed to cause the potentiation of the genotoxic and mutagenic effects of DNA damaging agents like UV-light or cisplation by metal ions. However, the precise underlying molecular mechanism of this phenomenon is still unknown. Using in vitro assays, we have determined the potential interference of several metal (II...

Asbestos promotes morphological transformation and elevates expression of a gene family invariably induced by tumor promoters in C3H/10T1/2 cells

The murine proliferin gene family, which has been shown to respond consistently to tumor promoters and other cellular pro-oxidant agents in C3H/10T1/2 cells, was used to monitor responses after treatment of these cell cultures with toxic, pro-oxidant asbestos fibres. Proliferin mRNA levels were increased by amosite, crocidolite or chrysotile asbestos fibres, especially in the...

Telomerase activation during the linear evolution of human fibroblasts to tumorigenicity in nude mice

The ribonucleoprotein enzyme telomerase is active in most immortal cell lines, most tumors and all tumor-derived cell lines. The enzyme is important because it prevents continual shortening of telomeres and therefore plays a significant role in chromosome maintenance. In man, telomerase is not active in most somaI cells with finite lifespans. Using the SV40 T antigen we...

Short exposures to tunicamycin induce apoptosis in SV40-transformed but not in normal human fibroblasts

When SV40-transformed fibroblasts (line 90VAVI) were exposed to tunicamycin, an inhibitor of N-linked glycosylation, an extensive cell death occured compared with untransformed fibroblasts. A considerable cell loss was obtained within 24 h after tunicamycin addition, and after 72 h there were hardly any virus-transformed cells alive. A 2-h pulse treatment with tunicamycin was...

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Anti-cancer effects of morphine through inhibition of tumour necrosis factor-α release and mRNA expression

Morphine is mainly used to relieve pain in the terminal stage of cancer patients. We found that morphine has inhibitory effects on growth of various human cancer cell lines, with IC50 from 2.7 to 8.8 mM, and BALB/3T3 cells, with IC50 of 1.5 mM. Although the IC50 values were relatively high, we decided to study the mechanisms of anti-carcinogenic effects of morphine. Morphine...

Release of sulfur mustard-modified DNA bases by Escherichia coli 3-methyladenine DNA glycosylase II

The toxic effects of sulfur mustard have been attributed to DNA modification with the formation of 7-hydroxyethyl-thioethyl guanine, 3-hydroxyethylthioethyl adenine and the cross-link, di-(2-guanin-7-yl-ethyl)sulfide. To investigate the action of bacterial 3-methyladenine DNA glycosylase II (Gly II) on these adducts, calf thymus DNA was modified with [14C]sulfur mustard and used...

Medroxyprogesterone acetate accelerates the development and increases the incidence of mouse mammary tumors induced by dimethylbenzanthracene

Chemical induction of mammary tumors in mice requires usually a long latency period and is often complicated by high non-mammary tumor related mortality. Classically hormone stimulation has been used as the means to increase tumor incidence. The synthetic progestin medroxyproges-terone acetate (MPA) was postulated by some authors to increase mammary tumor incidence in various...

Gene expression and cellular sources of inducible nitric oxide synthase during tumor promotion

The present studies examined the temporal sequence of inducible nitric oxide synthase (iNOS) gene expression and the cellular sources of iNOS protein and of 3-nitrotyrosine, as a marker of production of nitric oxide-derived reactive nitrogen intermediates during murine multi-stage carcino-genesis. Levels of iNOS mRNA in dorsal skin isolated from acetone-treated female Sencar mice...