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- Block, Keith I., et al.
(författare)
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Designing a broad-spectrum integrative approach for cancer prevention and treatment
- 2015
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Ingår i: Seminars in Cancer Biology. - : Academic Press. - 1044-579X .- 1096-3650. ; 35, s. S276-S304
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Forskningsöversikt (refereegranskat)abstract
- Targeted therapies and the consequent adoption of "personalized" oncology have achieved notable successes in some cancers; however, significant problems remain with this approach. Many targeted therapies are highly toxic, costs are extremely high, and most patients experience relapse after a few disease-free months. Relapses arise from genetic heterogeneity in tumors, which harbor therapy-resistant immortalized cells that have adopted alternate and compensatory pathways (i.e., pathways that are not reliant upon the same mechanisms as those which have been targeted). To address these limitations, an international task force of 180 scientists was assembled to explore the concept of a low-toxicity "broadspectrum" therapeutic approach that could simultaneously target many key pathways and mechanisms. Using cancer hallmark phenotypes and the tumor microenvironment to account for the various aspects of relevant cancer biology, interdisciplinary teams reviewed each hallmark area and nominated a wide range of high-priority targets (74 in total) that could be modified to improve patient outcomes. For these targets, corresponding low-toxicity therapeutic approaches were then suggested, many of which were phytochemicals. Proposed actions on each target and all of the approaches were further reviewed for known effects on other hallmark areas and the tumor microenvironment Potential contrary or procarcinogenic effects were found for 3.9% of the relationships between targets and hallmarks, and mixed evidence of complementary and contrary relationships was found for 7.1%. Approximately 67% of the relationships revealed potentially complementary effects, and the remainder had no known relationship. Among the approaches, 1.1% had contrary, 2.8% had mixed and 62.1% had complementary relationships. These results suggest that a broad-spectrum approach should be feasible from a safety standpoint. This novel approach has potential to be relatively inexpensive, it should help us address stages and types of cancer that lack conventional treatment, and it may reduce relapse risks. A proposed agenda for future research is offered. (C) 2015 The Authors. Published by Elsevier Ltd.
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| 2. |
- Killela, Patrick J., et al.
(författare)
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TERT promoter mutations occur frequently in gliomas and a subset of tumors derived from cells with low rates of self-renewal
- 2013
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Ingår i: Proceedings of the National Academy of Sciences. - : Proceedings of the National Academy of Sciences. - 1091-6490 .- 0027-8424. ; 110:15, s. 6021-6026
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Tidskriftsartikel (refereegranskat)abstract
- Malignant cells, like all actively growing cells, must maintain their telomeres, but genetic mechanisms responsible for telomere maintenance in tumors have only recently been discovered. In particular, mutations of the telomere binding proteins alpha thalassemia/mental retardation syndrome X-linked (ATRX) or death-domain associated protein (DAXX) have been shown to underlie a telomere maintenance mechanism not involving telomerase (alternative lengthening of telomeres), and point mutations in the promoter of the telomerase reverse transcriptase (TERT) gene increase telomerase expression and have been shown to occur in melanomas and a small number of other tumors. To further define the tumor types in which this latter mechanism plays a role, we surveyed 1,230 tumors of 60 different types. We found that tumors could be divided into types with low (<15%) and high (>= 15%) frequencies of TERT promoter mutations. The nine TERT-high tumor types almost always originated in tissues with relatively low rates of self renewal, including melanomas, liposarcomas, hepatocellular carcinomas, urothelial carcinomas, squamous cell carcinomas of the tongue, medulloblastomas, and subtypes of gliomas (including 83% of primary glioblastoma, the most common brain tumor type). TERT and ATRX mutations were mutually exclusive, suggesting that these two genetic mechanisms confer equivalent selective growth advantages. In addition to their implications for understanding the relationship between telomeres and tumorigenesis, TERT mutations provide a biomarker that may be useful for the early detection of urinary tract and liver tumors and aid in the classification and prognostication of brain tumors.
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| 3. |
- Stewénius, Ylva, et al.
(författare)
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Defective chromosome segregation and telomere dysfunction in aggressive Wilms' tumors
- 2007
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Ingår i: Clinical Cancer Research. - 1078-0432. ; 13:22, s. 6593-6602
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: In many childhood neoplasms, prognostic subgroups have been defined based on specific chromosome changes. In Wilms' tumor (WT), such subclassification has been hampered by the diverse and relatively unspecific pattern of chromosomal imbalances present in these tumors. Unspecific patterns of cytogenetic imbalances in tumors are often caused by mitotic segregation errors due to short dysfunctional telomeres. As an alternative to cytogenetic classification, we therefore have evaluated whether the rate of telomere-dependent chromosomal instability could influence the clinical course inWT patients. Experimental Design: Telomere function and mitotic segregation errors were assessed in 12 cultured tumors and in tumor tissue sections from 41 WT patients. Results: Abnormal telomere shortening was found in cultured cells and in tissue sections from highly aggressive tumors. In vitro, dysfunctional telomeres were associated to specific cell division abnormalities, including anaphase bridges and multipolar mitoses. Assessment of mitotic figures in tissue sections revealed that anaphase bridges and multipolar mitoses were predominantly, but not exclusively, present in high-risk tumors and were predictors of poor event-free and overall survival. Conclusions: Telomere-dependent mitotic instability is present in a subgroup of WT predominately consisting of high-risk tumors.
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