In vitro assays for determining the metastatic potential of melanoma cell lines with characterized in vivo invasiveness

2016 ◽  
Vol 18 (5) ◽  
Author(s):  
Siddarth Chandrasekaran ◽  
Ut-Binh T. Giang ◽  
Lei Xu ◽  
Lisa A. DeLouise
Keyword(s):  
Cell Lines ◽  
Melanoma Cell ◽  
Metastatic Potential ◽  
In Vitro Assays ◽  
Melanoma Cell Lines

scholarly journals Rare Stochastic Expression of O6-Methylguanine- DNA Methyltransferase (MGMT) in MGMT-Negative Melanoma Cells Determines Immediate Emergence of Drug-Resistant Populations upon Treatment with Temozolomide In Vitro and In Vivo

Cancers ◽  
2018 ◽  
Vol 10 (10) ◽  
pp. 362 ◽  
Author(s):  
Thomas Chen ◽  
Nymph Chan ◽  
Radu Minea ◽  
Hannah Hartman ◽  
Florence Hofman ◽  
...  
Keyword(s):  
Tumor Growth ◽  
Cell Lines ◽  
Melanoma Cell ◽  
Dna Methyltransferase ◽  
Tumor Tissue ◽  
Methylguanine Dna Methyltransferase ◽  
Stochastic Expression ◽  
Melanoma Cell Lines

The chemotherapeutic agent temozolomide (TMZ) kills tumor cells preferentially via alkylation of the O6-position of guanine. However, cells that express the DNA repair enzyme O6-methylguanine-DNA methyltransferase (MGMT), or harbor deficient DNA mismatch repair (MMR) function, are profoundly resistant to this drug. TMZ is in clinical use for melanoma, but objective response rates are low, even when TMZ is combined with O6-benzylguanine (O6BG), a potent MGMT inhibitor. We used in vitro and in vivo models of melanoma to characterize the early events leading to cellular TMZ resistance. Melanoma cell lines were exposed to a single treatment with TMZ, at physiologically relevant concentrations, in the absence or presence of O6BG. Surviving clones and mass cultures were analyzed by Western blot, colony formation assays, and DNA methylation studies. Mice with melanoma xenografts received TMZ treatment, and tumor tissue was analyzed by immunohistochemistry. We found that MGMT-negative melanoma cell cultures, before any drug treatment, already harbored a small fraction of MGMT-positive cells, which survived TMZ treatment and promptly became the dominant cell type within the surviving population. The MGMT-negative status in individual cells was not stable, as clonal selection of MGMT-negative cells again resulted in a mixed population harboring MGMT-positive, TMZ-resistant cells. Blocking the survival advantage of MGMT via the addition of O6BG still resulted in surviving clones, although at much lower frequency and independent of MGMT, and the resistance mechanism of these clones was based on a common lack of expression of MSH6, a key MMR enzyme. TMZ treatment of mice implanted with MGMT-negative melanoma cells resulted in effective tumor growth delay, but eventually tumor growth resumed, with tumor tissue having become MGMT positive. Altogether, these data reveal stochastic expression of MGMT as a pre-existing, key determinant of TMZ resistance in melanoma cell lines. Although MGMT activity can effectively be eliminated by pharmacologic intervention with O6BG, additional layers of TMZ resistance, although considerably rarer, are present as well and minimize the cytotoxic impact of TMZ/O6BG combination treatment. Our results provide rational explanations regarding clinical observations, where the TMZ/O6BG regimen has yielded mostly disappointing outcomes in melanoma patients.

scholarly journals NCRs and DNAM-1 mediate NK cell recognition and lysis of human and mouse melanoma cell lines in vitro and in vivo

2009 ◽  
Vol 119 (5) ◽  
pp. 1251-1263 ◽  
Author(s):  
Tadepally Lakshmikanth ◽  
Shannon Burke ◽  
Talib Hassan Ali ◽  
Silvia Kimpfler ◽  
Francesco Ursini ◽  
...  
Keyword(s):  
Cell Lines ◽  
Melanoma Cell ◽  
Nk Cell ◽  
Cell Recognition ◽  
Mouse Melanoma ◽  
Mouse Melanoma Cell ◽  
Human And Mouse ◽  
Melanoma Cell Lines

scholarly journals Role of Flavonoids in the Prevention of AhR-Dependent Resistance During Treatment with BRAF Inhibitors

2020 ◽  
Vol 21 (14) ◽  
pp. 5025
Author(s):  
Héloïse M. Leclair ◽  
Nina Tardif ◽  
Anaïs Paris ◽  
Marie-Dominique Galibert ◽  
Sébastien Corre
Keyword(s):  
Cell Lines ◽  
Melanoma Cell ◽  
Therapeutic Potential ◽  
Progression Free Survival ◽  
Human Melanoma ◽  
Human Melanoma Cell ◽  
Melanoma Cell Lines

BRAF and MEK inhibitors (BRAFi and MEKi) are the standard of care for the treatment of metastatic melanoma in patients with BRAFV600E mutations, greatly improving progression-free survival. However, the acquisition of resistance to BRAFi and MEKi remains a difficult clinical challenge, with limited therapeutic options available for these patients. Here, we investigated the therapeutic potential of natural flavonoids as specific AhR (Aryl hydrocarbon Receptor) transcription factor antagonists in combination with BRAFi. Experimental Design: Experiments were performed in vitro and in vivo with various human melanoma cell lines (mutated for BRAFV600E) sensitive or resistant to BRAFi. We evaluated the role of various flavonoids on cell sensitivity to BRAFi and their ability to counteract resistance and the invasive phenotype of melanoma. Results: Flavonoids were highly effective in potentiating BRAFi therapy in human melanoma cell lines by increasing sensitivity and delaying the pool of resistant cells that arise during treatment. As AhR antagonists, flavonoids counteracted a gene expression program associated with the acquisition of resistance and phenotype switching that leads to an invasive and EMT-like phenotype. Conclusions: The use of natural flavonoids opens new therapeutic opportunities for the treatment of patients with BRAF-resistant disease.

scholarly journals Inhibition of the Myocardin-Related Transcription Factor Pathway Increases Efficacy of Trametinib in NRAS-Mutant Melanoma Cell Lines

Cancers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 2012
Author(s):  
Kathryn M. Appleton ◽  
Charuta C. Palsuledesai ◽  
Sean A. Misek ◽  
Maja Blake ◽  
Joseph Zagorski ◽  
...  
Keyword(s):  
Cell Lines ◽  
Melanoma Cell ◽  
Therapeutic Potential ◽  
Mapk Pathway ◽  
Mek Inhibitor ◽  
Intrinsic Resistance ◽  
Primary Resistance ◽  
Induced Apoptosis ◽  
Melanoma Cell Lines

The Ras/MEK/ERK pathway has been the primary focus of targeted therapies in melanoma; it is aberrantly activated in almost 80% of human cutaneous melanomas (≈50% BRAFV600 mutations and ≈30% NRAS mutations). While drugs targeting the MAPK pathway have yielded success in BRAFV600 mutant melanoma patients, such therapies have been ineffective in patients with NRAS mutant melanomas in part due to their cytostatic effects and primary resistance. Here, we demonstrate that increased Rho/MRTF-pathway activation correlates with high intrinsic resistance to the MEK inhibitor, trametinib, in a panel of NRAS mutant melanoma cell lines. A combination of trametinib with the Rho/MRTF-pathway inhibitor, CCG-222740, synergistically reduced cell viability in NRAS mutant melanoma cell lines in vitro. Furthermore, the combination of CCG-222740 with trametinib induced apoptosis and reduced clonogenicity in SK-Mel-147 cells, which are highly resistant to trametinib. These findings suggest a role of the Rho/MRTF-pathway in intrinsic trametinib resistance in a subset of NRAS mutant melanoma cell lines and highlight the therapeutic potential of concurrently targeting the Rho/MRTF-pathway and MEK in NRAS mutant melanomas.

In vitro synergy of paclitaxel (Taxol) and vinorelbine (navelbine) against human melanoma cell lines

1997 ◽  
Vol 33 (3) ◽  
pp. 463-470 ◽  
Author(s):  
A. Photiou ◽  
P. Shah ◽  
L.K. Leong ◽  
J. Moss ◽  
S. Retsas
Keyword(s):  
Cell Lines ◽  
Melanoma Cell ◽  
Human Melanoma ◽  
Human Melanoma Cell ◽  
Melanoma Cell Lines

scholarly journals Expression of cd44 splice variants in human cutaneous melanoma and melanoma cell lines is related to tumor progression and metastatic potential

1995 ◽  
Vol 64 (3) ◽  
pp. 182-188 ◽  
Author(s):  
Eveliene Manten-Horst ◽  
Erik H. J. Danen ◽  
Lia Smit ◽  
Margriet Snoek ◽  
I. Le Caroline Poole ◽  
...  
Keyword(s):  
Tumor Progression ◽  
Cell Lines ◽  
Melanoma Cell ◽  
Cutaneous Melanoma ◽  
Splice Variants ◽  
Metastatic Potential ◽  
Melanoma Cell Lines
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