| 1. |
- Bivik, Cecilia, et al.
(författare)
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Hsp70 protects against UVB induced apoptosis by preventing release of cathepsins and cytochrome c in human melanocytes
- 2007
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 28:3, s. 537-544
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Tidskriftsartikel (refereegranskat)abstract
- Stress-induced heat shock protein 70 (Hsp70) effectively protects cells against apoptosis, although the anti-apoptotic mechanism is still undefined. Exposure of human melanocytes to heat and subsequent UVB irradiation increased the level of Hsp70 and pre-heating reduced UVB induced apoptosis. Immunofluorescence staining of Hsp70 in combination with staining of lysosomes (Lamp2) or mitochondria (Mitotracker®) in pre-heated UVB exposed cells showed co-localization of Hsp70 with both lysosomes and mitochondria in the surviving cell population. Furthermore, UVB induced apoptosis was accompanied by lysosomal and mitochondrial membrane permeabilization, detected as release of cathepsin D and cytochrome c, respectively, which were prevented by heat pre-treatment. In purified fractions of lysosomes and mitochondria, recombinant Hsp70 attached to both lysosomal and mitochondrial membranes. Moreover, in apoptotic cells Bax was translocated from a diffuse cytosolic location into punctate mitochondrial-like structures, which was inhibited by Hsp70 induction. Such inhibition of Bax translocation was abolished by transfection with Hsp70 siRNA. Furthermore, Hsp70 siRNA eliminated the apoptosis preventive effect observed after pre-heating. These findings show Hsp70 to rescue melanocytes from UVB induced apoptosis by preventing release of cathepsins from lysosomes, Bax translocation and cytochrome c release from mitochondria. Abbreviations: AIF, apoptosis-inducing factor; Hsp, heat shock protein; NAG, ß-N-acetylglucosaminidase; tBid, truncated Bid; UV, ultraviolet
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| 2. |
- Castro, Victor M, et al.
(författare)
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Differences among human tumor cell lines in the expression of glutathione transferases and other glutathione-linked enzymes
- 1990
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Ingår i: Carcinogenesis. - : Oxford University Press. - 0143-3334 .- 1460-2180. ; 11:9, s. 1569-1576
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Tidskriftsartikel (refereegranskat)abstract
- A large number of human tumor cell lines of various origins have been investigated with respect to expression of glutathione-linked enzymes in the cytosol fraction. The amounts of the different enzymes were estimated by use of activity measurements and by silver staining or immunoblot analysis after electrophoresis of cytosol fractions purified by affinity chromatography on S-hexylglutathione Sepharose. Class Pi glutathione transferase was the most abundant enzyme in most tumor cells; the cell lines HepG2 and Raji were exceptions in not expressing significant amounts of this enzyme. HepG2 cells derive from hepatocytes, which normally do not express the class Pi enzyme, whereas Raji cells originate from B-lymphocytes, which normally do express a class Pi glutathione transferase. The highest level of the class Pi transferase, in terms of protein reacting with antibodies as well as enzyme activity, was noted in the colon carcinoma cell line LS174T. Hu549Pat cells, EBV-transformed B-lymphocytes, also expressed high levels of a protein reacting with antibodies specific for class Pi glutathione transferases, but did not display any significant activity with ethacrynic acid, a substrate characteristic for this class. Class Alpha and class Mu glutathione transferases, in cell lines expressing these isoenzymes, were present in significantly lower concentrations than the class Pi enzyme. Most of the tumor cells contained a class Alpha transferase composed of 27.5 kd subunits, which has the physicochemical and immunological properties of the most basic glutathione transferase found in human skin. In several cell lines, a protein was detected with an apparent subunit Mr value of 30 kd that was tentatively identified as an additional class Alpha glutathione transferase not previously described. In addition, other glutathione-linked enzyme activities, namely glutathione peroxidase, glutathione reductase and glyoxalase I, were assayed with specific substrates in the cytosolic fraction of the tumor cells; glyoxalase I could also be estimated semiquantitatively by silver staining of SDS-PAGE cells after affinity chromatography. Like the glutathione transferases, these enzymes displayed distinctly different levels of expression in the various cell lines. Thus, virtually every cell line was found to have a unique pattern of glutathione-linked enzymes, suggesting that the resistance phenotypes of the cells differ accordingly.
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| 3. |
- Farahani, Ensieh, et al.
(författare)
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Cell adhesion molecules and their relation to (cancer) cell stemness
- 2014
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Ingår i: Carcinogenesis. - : Oxford University Press. - 0143-3334 .- 1460-2180. ; 35:4, s. 747-759
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Forskningsöversikt (refereegranskat)abstract
- Despite decades of search for anticancer drugs targeting solid tumors, this group of diseases remains largely incurable, especially if in advanced, metastatic stage. In this review, we draw comparison between reprogramming and carcinogenesis, as well as between stem cells (SCs) and cancer stem cells (CSCs), focusing on changing garniture of adhesion molecules. Furthermore, we elaborate on the role of adhesion molecules in the regulation of (cancer) SCs division (symmetric or asymmetric), and in evolving interactions between CSCs and extracellular matrix. Among other aspects, we analyze the role and changes of expression of key adhesion molecules as cancer progresses and metastases develop. Here, the role of cadherins, integrins, as well as selected transcription factors like Twist and Snail is highlighted, not only in the regulation of epithelial-to-mesenchymal transition but also in the avoidance of anoikis. Finally, we briefly discuss recent developments and new strategies targeting CSCs, which focus on adhesion molecules or targeting tumor vasculature.
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| 4. |
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| 5. |
- Hu, Zhiwei, et al.
(författare)
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Assessing the carcinogenic potential of low-dose exposures to chemical mixtures in the environment: focus on the cancer hallmark of tumor angiogenesis
- 2015
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP): Policy B - Oxford Open Option B. - 0143-3334 .- 1460-2180. ; 36, s. S184-S202
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Forskningsöversikt (refereegranskat)abstract
- Angiogenesis is an important hallmark of cancer. We reviewed the various pathways controlling angiogenesis, summarized the possible role of specific environmental chemicals disrupting these pathways and listed assays for assessing the effects of low-dose exposures to chemicals in promoting tumor angiogenesis.One of the important hallmarks of cancer is angiogenesis, which is the process of formation of new blood vessels that are necessary for tumor expansion, invasion and metastasis. Under normal physiological conditions, angiogenesis is well balanced and controlled by endogenous proangiogenic factors and antiangiogenic factors. However, factors produced by cancer cells, cancer stem cells and other cell types in the tumor stroma can disrupt the balance so that the tumor microenvironment favors tumor angiogenesis. These factors include vascular endothelial growth factor, endothelial tissue factor and other membrane bound receptors that mediate multiple intracellular signaling pathways that contribute to tumor angiogenesis. Though environmental exposures to certain chemicals have been found to initiate and promote tumor development, the role of these exposures (particularly to low doses of multiple substances), is largely unknown in relation to tumor angiogenesis. This review summarizes the evidence of the role of environmental chemical bioactivity and exposure in tumor angiogenesis and carcinogenesis. We identify a number of ubiquitous (prototypical) chemicals with disruptive potential that may warrant further investigation given their selectivity for high-throughput screening assay targets associated with proangiogenic pathways. We also consider the cross-hallmark relationships of a number of important angiogenic pathway targets with other cancer hallmarks and we make recommendations for future research. Understanding of the role of low-dose exposure of chemicals with disruptive potential could help us refine our approach to cancer risk assessment, and may ultimately aid in preventing cancer by reducing or eliminating exposures to synergistic mixtures of chemicals with carcinogenic potential.
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| 6. |
- Pfeifer, Daniella, et al.
(författare)
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Polymorphism of the p73 gene in relation to colorectal cancer risk and survival
- 2005
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 26:1, s. 103-107
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Tidskriftsartikel (refereegranskat)abstract
- The results regarding a GC/AT polymorphism in the p73 gene in relation to cancer risk are inconsistent, and the significance of loss of heterozygosity (LOH) of the gene is unclear. In the present study, we investigated whether this polymorphism was related to the risk of colorectal cancer, and whether there were relationships between the polymorphism and LOH, protein expression or clinicopathological variables. 179 patients with colorectal cancer and 260 healthy controls were genotyped for the polymorphism by PCR-restriction fragment length polymorphism (RFLP). Fifty informative cases were examined for LOH in tumours. Immunohistochemistry was performed on distant (n = 42) and adjacent normal mucosa (n = 33), primary tumour (n = 6 9) and lymph node metastasis (n = 12). The frequencies of the genotypes were 63% for wild-type (GC/GC), 30% for heterozygotes (GC/AT) and 7% for variants (AT/AT) in patients, and 62, 36 and 2% in controls, respectively. The frequencies of the genotypes in the patients and controls were significantly different (P = 0.02). The patients carrying the AT allele had a better prognosis than those with the GC/GC genotype (OR = 0.42, 95% CI = 1.15-5.02, P = 0.02). No LOH was observed at the p73 locus. Expression of p73 protein was increased from normal mucosa to primary tumours (P = 0.02), but was not significantly changed between primary tumours and metastases (P = 1.0). In conclusion, the AT/AT homozygotes may have a greater risk of developing colorectal cancer, while the patients who carried the AT allele had a better prognosis.
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| 7. |
- Ungerbäck, Jonas, et al.
(författare)
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Genetic variation and alterations of genes involved in NFκB/TNFAIP3- and NLRP3-inflammasome signaling affect susceptibility and outcome of colorectal cancer
- 2012
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Ingår i: Carcinogenesis. - Oxford, United kingdom : Oxford University Press. - 0143-3334 .- 1460-2180. ; 33:11, s. 2126-2134
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Tidskriftsartikel (refereegranskat)abstract
- Colorectal tumors are continuously exposed to an inflammatory environment, which together with mitogenic signals sustain several cancer hallmarks. Nuclear factor-kappa B (NFκB) is a major regulator of inflammation and variation in NFκB-associated genes could potentially be used as biomarkers to identify patients with increased risk of colorectal cancer (CRC) development, and/or a rapidly progressing disease. In this study, 348 CRC cases and 806 randomly selected healthy individuals from southeastern Sweden were examined with regard to seven polymorphisms in NFκB pathway-associated genes. Log-rank-tests and Cox proportional hazard regression analysis examined the association between the polymorphisms and CRC-specific survival, whereas chi-square tests and logistic regression analysis were used to test for associations between the polymorphisms and CRC susceptibility. Gene expression and loss of heterozygosity analyses of TNFAIP3 were carried out in a subset of tumors to assess its role as a tumor suppressor in CRC. Heterozygous and polymorphic TNFAIP3 (rs6920220), heterozygous NLRP3 (Q705K) and polymorphic NFκB -94 ATTG ins/del genotypes were found to be associated with poorer survival in patients diagnosed with invasive CRC (aHR = 5.2, 95% CI: 2.5-10.9, P < 0.001). TNFAIP3 mRNA levels were significantly decreased in tumors compared with adjacent non-neoplastic mucosa (P < 0.0001) and loss of heterozygosity of 6q23.3 (TNFAIP3) was detected in 17% of cases, whereas only 2.5% of the investigated specimens displayed TNFAIP3 gene mutations. We propose that TNFAIP3 (rs6920220), NLRP3 (Q705K) and NFκB -94 ATTG ins/del polymorphisms are associated with poor survival in patients with advanced CRC and may be used as prognostic markers. Experimental results indicate that TNFAIP3 may act as a tumor suppressor in CRC.
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| 8. |
- Zhang, Hong, 1957-, et al.
(författare)
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All-trans retinoic acid (atRA) differentially induces apoptosis in matched primary and metastatic melanoma cells - A speculation on damage effect of atRA via mitochondrial dysfunction and cell cycle redistribution
- 2003
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 24:2, s. 185-191
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Tidskriftsartikel (refereegranskat)abstract
- All-trans retinoic acid (atRA) has been suggested to exert its cytotoxicity via apoptosis but the mechanisms behind the damage effects have not been fully understood. In this study, we investigated the cytotoxic effects of atRA in eleven primary and matched metastatic cutaneous melanoma cell lines. All the primary and metastatic melanoma cell lines examined expressed the retinoic acid receptors. The cultured melanoma cells treated with atRA showed dysfunction of mitochondria and altered cell cycle distribution, inhibited cell proliferation and apoptosis. The cytotoxic effects of atRA were dose- and time-dependent. The dysfunction of mitochondria and altered cell cycle distribution, inhibited cell proliferation and apoptosis. The cytotoxic effects of atRA were dose- and time-dependent. The dysfunction of mitochondria and induction of apoptosis were more pronounced in the primary tumor cells than in the metastatic cell lines from the same patients. The data indicate that the cytotoxic effect of atRA was mediated through dysfunction of mitochondria, alterations in cell cycle and induction of apoptosis. Melanoma in early stage may have better response to atRA adjuvant therapy than the melanoma in late stage, suggesting the early utility of atRA in melanoma chemotherapy.
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| 9. |
- Zhang, Hong, 1957-, et al.
(författare)
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Ultraviolet A and B differently induce intracellular protein expression in human skin melanocytes - A speculation of separate pathways in initiation of melanoma
- 2003
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Ingår i: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 24:12, s. 1929-1934
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Tidskriftsartikel (refereegranskat)abstract
- Ultraviolet (UV) irradiation has been involved in both initiation and promotion of carcinogenesis in melanoma. Alterations of cellular proliferation proteins, such as p73, Nup88, Id1 and p27 have been considered to play critical roles in melanoma development. However, the molecular mechanisms behind melanoma carcinogenesis are still poorly understood. In this study, we used human skin melanocytes as an experimental model system to investigate effects of UV irradiation on protein expression concerning cellular proliferation. The melanocytes prepared from human foreskin were separately exposed to various doses of UVA or UVB and post-cultivated for 24 or 48 h. Total proteins were isolated from the melanocytes, and expression of p73, Nup88, Id1, p27, bcl-2 and proliferating cell nuclear antigen (PCNA) proteins was examined by western blotting and immunocytochemistry. Results showed that expression of p73 and Nup88 was enhanced by UVA irradiation in a dose- and time-dependent manner. However, expression of Id1, p27, bcl-2 and PCNA proteins was not changed upon exposure to the UVA. Id1 and p27 proteins were over-expressed by exposure to UVB, but expression of p73, Nup88, bcl-2 and PCNA proteins was not changed by the UVB irradiation. The data suggested that UVA and UVB irradiation might lead to alterations of the different intracellular proteins. UVA enhanced protein expression concerning cell growth (p73 and Nup88) and UVB might over-express proteins concerning cellular proliferation (Id1 and p27). UVA and UVB may induce initiation of melanoma via separate intracellular pathways.
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