Clonal analysis of the malignant properties of B16 melanoma cells treated with the DNA hypomethylating agent 5-azacytidine

Trainer, Deborah L.; Kline, Thomas; Hensler, Gary L.; Greig, Russell; Poste, George

doi:10.1007/bf01782479

Cited by 12 publications

(4 citation statements)

References 32 publications

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“…Trainer and co-workers later showed that treatment of murine melanoma cells with the DNA de-methylating agent 5-azacytidine resulted in reversible reduction of metastatic lung colonization (43). Recent studies have shown that treatment of cells with 5-azacytidine can induce expression of the metastasis suppressor genes Nm23 (44) and KAI1 (45).…”

Section: Discussionmentioning

confidence: 99%

Breast Cancer Metastasis Suppressor 1 (BRMS1) Forms Complexes with Retinoblastoma-binding Protein 1 (RBP1) and the mSin3 Histone Deacetylase Complex and Represses Transcription

Meehan

Samant

Hopper

et al. 2004

Journal of Biological Chemistry

159

139

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Breast cancer metastasis suppressor 1 (BRMS1) suppresses metastasis of multiple human and murine cancer cells without inhibiting tumorigenicity. By yeast two-hybrid and co-immunoprecipitation, BRMS1 interacts with retinoblastoma binding protein 1 and at least seven members of the mSin3 histone deacetylase (HDAC) complex in human breast and melanoma cell lines. BRMS1 co-immunoprecipitates enzymatically active HDAC proteins and represses transcription when recruited to a Gal4 promoter in vivo. BRMS1 exists in large mSin3 complex(es) of ϳ1.4 -1.9 MDa, but also forms smaller complexes with HDAC1. Deletion analyses show that the carboxyl-terminal 42 amino acids of BRMS1 are not critical for interaction with much of the mSin3 complex and that BRMS1 appears to have more than one binding point to the complex. These results further show that BRMS1 may participate in transcriptional regulation via interaction with the mSin3⅐HDAC complex and suggest a novel mechanism by which BRMS1 might suppress cancer metastasis.The complex process of cancer cell dissemination and the establishment of secondary foci involves the acquisition of multiple abilities by metastatic cells. For example, blood-borne metastasis requires cells to invade from the primary tumor, enter the circulation, survive transport, arrest at a secondary site, recruit a blood supply, and proliferate at that site (1). The ability to accomplish all of these steps likely involves changes in, and coordinated expression of, a large assortment of genes. Consistent with this notion, several genes, proteins, and pathways have been associated with metastatic progression, including oncogenes, motility factors, and matrix metalloproteinases (1, 2). In addition to metastasis-promoting genes, a new class of molecules called metastasis suppressors has been described (reviewed in Refs. 2-5). By definition, metastasis suppressors inhibit metastasis without blocking primary tumor growth, presumably by inhibiting one or more steps necessary for metastasis. To date, 13 metastasis suppressor genes have been identified that reduce the metastatic ability of cancer cell line(s) in vivo without affecting tumorigenicity, namely breast cancer metastasis suppressor 1 (BRMS1), 1 CRSP3, DRG1, KAI1, KISS1, MKK4, NM23, RhoGDI2, RKIP, SSeCKs, VDUP1, E-cadherin, and TIMPs (reviewed in Refs. 4 and 5).We identified BRMS1 using differential display to compare highly metastatic breast carcinoma cells with related but metastasis-suppressed cells (6). Enforced expression of BRMS1 suppressed metastasis in three animal models, namely human breast (6), murine mammary (7), and human melanoma cells (8). Additionally, BRMS1 mapped to loci in murine (7) and human (6) genomes that had previously been implicated in metastasis control (9). The BRMS1 protein localized to nuclei and restored gap junctional intercellular communication in both breast and melanoma tumor cell lines (8,10,11), but its molecular functions remain to be elucidated.One approach to determine a mechanism of action involves identifying which...

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Section: Discussionmentioning

confidence: 99%

Breast Cancer Metastasis Suppressor 1 (BRMS1) Forms Complexes with Retinoblastoma-binding Protein 1 (RBP1) and the mSin3 Histone Deacetylase Complex and Represses Transcription

Meehan

Samant

Hopper

et al. 2004

Journal of Biological Chemistry

159

139

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“…Support for this model comes from studies demonstrating that methylation inhibitors can modulate the metastatic capacity of cell lines [ 24 - 28 ]. However, while global demethylation may mimic some of the proposed epigenetic events, these agents can cause chromosomal aberrations [ 29 ], opening up the possibility that the modulation of metastatic capacity was due to mutational rather than epigenetic events.…”

Section: The Transient Compartment Modelsmentioning

confidence: 99%

Mechanisms of metastasis

2008

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Metastasis is an enormously complex process that remains to be a major problem in the management of cancer. The fact that cancer patients might develop metastasis after years or even decades from diagnosis of the primary tumor makes the metastatic process even more complex. Over the years many hypotheses were developed to try to explain the inefficiency of the metastatic process, but none of these theories completely explains the current biological and clinical observations. In this review we summarize some of the proposed models that were developed in attempt to understand the mechanisms of tumor dissemination and colonization as well as metastatic progression.Metastasis is an extraordinarily complex process. To successfully colonize a secondary site a cancer cell must complete a sequential series of steps before it becomes a clinically detectable lesion. These steps typically include separation from the primary tumor, invasion through surrounding tissues and basement membranes, entry and survival in the circulation, lymphatics or peritoneal space and arrest in a distant target organ. These are usually, but not always [1], followed by extravasation into the surrounding tissue, survival in the foreign microenvironment, proliferation, and induction of angiogenesis, all the while evading apoptotic death or immunological response (Figure 1Metastasis is of great importance to the clinical management of cancer since the majority of cancer mortality is associated with disseminated disease rather than the primary tumor [2]. In most cases cancer patients with localized tumors have significantly better prognoses than those with disseminated tumors. Recent evidence suggests that the first stages of metastasis can be an early event [3] and that 60% to 70% of patients have initiated the metastatic process by the time of diagnosis. Therefore, an improved understanding of the factors leading to tumor dissemination is of vital importance. However, even patients that have no evidence of tumor dissemination at presentation are at risk for metastatic disease. Approximately one-third of women who are sentinel lymph node negative at the time of surgical resection of the primary breast tumor will subsequently develop clinically detectable secondary tumors [4]. Even patients with small primary tumors and node negative status (T1N0) at surgery have a significant (15% to 25%) chance of developing distant metastases [5].In spite of the prevalence of secondary tumors in cancer patients, metastasis is an extremely inefficient process. To successfully colonize a distant site, a cancer cell must complete all of the steps of the cascade. Failure to complete any one step results in failure to colonize and proliferate in the distant organ. As a result, tumors can shed millions of cells into the bloodstream daily [6], yet very few clinically relevant metastases are formed [7]. Although many steps in the metastatic process are thought to contribute to metastatic inefficiency, our incomplete understanding of this process suggests that we ...

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“…It is known that the activity of certain genes depends on their methylation state [3,4,26]. Treatment of a variety of tumor cell lines with the DNA hypomethylating agent 5-azacytidine (5-aza-C) resulted in the emergence of clones that behave less aggressively (as defined by tumorigenicity in syngeneic hosts) or more aggressively (as defined by increased ability to metastasize) than the parent untreated cell line [14,21,33]. Treatment of a variety of tumor cell lines with the DNA hypomethylating agent 5-azacytidine (5-aza-C) resulted in the emergence of clones that behave less aggressively (as defined by tumorigenicity in syngeneic hosts) or more aggressively (as defined by increased ability to metastasize) than the parent untreated cell line [14,21,33].…”

Section: Introductionmentioning

confidence: 99%

Induction of invasive and metastatic potential in mouse T-lymphoma cells (BW5147) by treatment with 5-azacytidine

et al. 1990

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Non-invasive, non-metastatic mouse BW5147 T-lymphoma cells were treated with non-mutagenic concentrations of the hypomethylating agent 5-azacytidine (5-aza-C). Subsequently, invasive variants were selected on monolayers of rat embryo fibroblasts. The estimated frequency of induction of invasive variants was smaller than 1 in 10(6) cells. We obtained several independent clones that were stable in the expression of the invasive phenotype. In contrast to the parental cell line, the highly invasive clones produced widespread metastases upon tail vein injection in all the syngeneic AKR mice tested, whereas clones with an intermediate level of invasiveness formed metastases only in part of the mice tested. DNA analysis using the methylation-sensitive and insensitive restriction enzymes, Hpa-II and Msp-I, respectively, showed that the DNA of the invasive variants remained hypomethylated, up to 6 months after 5-aza-C treatment. 5-aza-C is thus able to induce invasive and metastatic potential in the BW5147 T-lymphoma cells, similar to the activated human c-Ha-ras oncogene or human chromosome 7, as studied previously. The acquisition of invasive and metastatic potential is presumably caused by DNA hypomethylation and thus activation of one or more silent invasion controlling genes.

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Clonal analysis of the malignant properties of B16 melanoma cells treated with the DNA hypomethylating agent 5-azacytidine

Cited by 12 publications

References 32 publications

Breast Cancer Metastasis Suppressor 1 (BRMS1) Forms Complexes with Retinoblastoma-binding Protein 1 (RBP1) and the mSin3 Histone Deacetylase Complex and Represses Transcription

Breast Cancer Metastasis Suppressor 1 (BRMS1) Forms Complexes with Retinoblastoma-binding Protein 1 (RBP1) and the mSin3 Histone Deacetylase Complex and Represses Transcription

Mechanisms of metastasis

Induction of invasive and metastatic potential in mouse T-lymphoma cells (BW5147) by treatment with 5-azacytidine

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