Effect of the farnesyl transferase inhibitor lonafarnib on sensitivity of melanoma cells to the multikinase inhibitor sorafenib and on Rheb farnesylation and mTOR signaling

2009 ◽  
Vol 27 (15_suppl) ◽  
pp. 9077-9077
Author(s):  
F. E. Meier ◽  
H. Niessner ◽  
K. Flaherty ◽  
D. Schadendorf ◽  
T. Sinnberg ◽  
...  

9077 Background: Farnesyl transferase inhibitors (FTIs) inhibit the post-translational farnesylation of a number of target proteins, including Ras and Rheb, preventing their signaling function. Ras signals to the RAF-MEK-ERK (MAPK) and PI3K-AKT-mTOR (AKT) signaling pathways which are constitutively activated in melanoma and appear to play a major role in tumor progression and drug resistance. Rheb positively regulates mTOR signaling. Methods: Using a panel of melanoma cell lines we evaluated the effects of the FTI lonafarnib alone and in combination with chemotherapeutic agents (temozolomide, cisplatin) or pharmacological MAPK pathway inhibitors (sorafenib, U0126, PD98059) or AKT pathway inhibitors (LY294002, wortmannin, rapamycin) on proliferation, survival and invasive tumor growth of melanoma cells in monolayer and organotypic culture. Results: Lonafarnib did not significantly inhibit growth of metastatic melanoma cells. Also, lonafarnib did not sensitize melanoma cells to the chemotherapeutic agents tested. Most combinations of the FTI lonafarnib with MAPK or AKT pathway inhibitors lacked significant enhancement of growth inhibition compared to monotherapy. In contrast, lonafarnib significantly augmented the growth inhibitory effects of the multikinase inhibitor sorafenib in eight metastatic melanoma cell lines tested. These effects did not appear to depend on BRAF or NRAS mutation status. Moreover, lonafarnib combined with sorafenib induced marked apoptosis and abrogated invasive melanoma growth. Interestingly, the FTI lonafarnib did not inhibit phosphorylation of ERK or AKT but of p70S6K, a downstream target of Rheb and mTOR signaling. Conclusions: These data suggest that lonafarnib sensitizes melanoma cells to sorafenib by inhibiting mTOR signaling via inhibition of Rheb farnesylation. No significant financial relationships to disclose.

2021 ◽  
Vol 22 (2) ◽  
pp. 537
Author(s):  
Paula Wróblewska-Łuczka ◽  
Aneta Grabarska ◽  
Magdalena Florek-Łuszczki ◽  
Zbigniew Plewa ◽  
Jarogniew J. Łuszczki

(1) Cisplatin (CDDP) is used in melanoma chemotherapy, but it has many side effects. Hence, the search for natural substances that can reduce the dose of CDDP, and CDDP-related toxicity, is highly desired. Coumarins have many biological properties, including anticancer and antiproliferative effects. (2) An in vitro 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay on two human melanoma cell lines (FM55P and FM55M2) examined the antitumor properties of CDDP and five naturally occurring coumarins (osthole, xanthotoxin, xanthotoxol, isopimpinellin, and imperatorin). The antiproliferative effects produced by combinations of CDDP with the coumarins were assessed using type I isobolographic analysis. (3) The most potent anticancer properties of coumarins were presented by osthole and xanthotoxol. These compounds were characterized by the lowest median inhibitory concentration (IC50) values relative to the FM55P and FM55M2 melanoma cells. Isobolographic analysis showed that for both melanoma cell lines, the combination of CDDP and osthole exerted synergistic and additive interactions, while the combination of CDDP and xanthotoxol exerted additive interactions. Combinations of CDDP with xanthotoxin, isopimpinellin, and imperatorin showed antagonistic and additive interactions in two melanoma cell lines. (4) The combination of CDDP and osthole was characterized by the most desirable synergistic interaction. Isobolographic analysis allows the selection of potential candidates for cancer drugs among natural substances.


1998 ◽  
Vol 30 (3) ◽  
pp. 189-194 ◽  
Author(s):  
Volker Enzmann ◽  
Frank Faude ◽  
Leon Kohen ◽  
Peter Wiedemann

Blood ◽  
1991 ◽  
Vol 78 (3) ◽  
pp. 609-615 ◽  
Author(s):  
GC Baldwin ◽  
DW Golde ◽  
GF Widhopf ◽  
J Economou ◽  
JC Gasson

Abstract Hematopoietic growth factor receptors are present on cells of normal nonhematopoietic tissues such as endothelium and placenta. We previously demonstrated functional human granulocyte-macrophage colony- stimulating factor (GM-CSF) receptors on small cell carcinoma of the lung cell lines, and others have reported that certain solid tumor cell lines respond to GM-CSF in clonogenic assays. In the current study, we examine human melanoma cell lines and fresh specimens of melanoma to determine whether they have functional GM-CSF receptors. Scatchard analyses of 125I-GM-CSF equilibrium binding to melanoma cell lines showed a mean of 542 +/- 67 sites per cell with a kd of 0.72 +/- 0.14 nmol/L. Cross-linking studies in the melanoma cell line, M14, showed a major GM-CSF receptor species of 84,000 daltons. Under the conditions tested, the M14 cells did not have a proliferative response to GM-CSF in vitro, nor was any induction of primary response genes detected by Northern analysis in response to GM-CSF. Studies to determine internal translocation of the receptor-ligand complex indicated less than 10% of the 125I-GM-CSF internalized was specifically bound to receptors. Primary melanoma cells from five surgical specimens had GM-CSF receptors; Scatchard analysis was performed on one sample, showing 555 sites/cell with a kd of 0.23 nmol/L. These results indicate that human tumor cells may express a low-affinity GM-CSF receptor protein that localizes to the cell surface and binds ligand, but lacks functional components or accessory factors needed to transduce a signal.


2011 ◽  
Vol 21 (1) ◽  
pp. 24-34 ◽  
Author(s):  
Shujie He ◽  
Caiyun G. Li ◽  
Lynn Slobbe ◽  
Amy Glover ◽  
Elaine Marshall ◽  
...  

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e13549-e13549
Author(s):  
Gregory B. Lesinski ◽  
Jennifer Yang ◽  
Matthew A Bill ◽  
Yosef Landesman ◽  
Sharon Shacham ◽  
...  

e13549 Background: Inhibition of nuclear export can promote re-activation of tumor suppressor pathways. CRM1 (chromosomal regional maintenance 1) or XPO1 (exportin 1) is the major protein that mediates nuclear export. We hypothesized that CRM1 mediated nuclear export represents a novel therapeutic target that can be manipulated to inhibit melanoma cell survival. Methods: The growth inhibitory and pro-apoptotic effects of KPT-185, KPT-276 and KPT-330, small molecules selective inhibitor of nuclear export (SINE) were evaluated in human melanoma cell lines using an MTT assay and Annexin V/PI staining, respectively. Fluorescence microscopy and immunoblots were used to assess nuclear accumulation of tumor suppressor proteins. The trans-isomer of KPT-185 and DMSO (vehicle) were used as a negative controls in all assays. The pharmacokinetic (PK) profile of all compounds was evaluated in mice. Results: CRM1 protein was highly expressed in human melanoma cell lines with diverse molecular profiles (i.e., B-Raf, NRAS, p53). KPT-SINE inhibited melanoma cell growth in a concentration-dependent manner and induced apoptosis at nanomolar concentrations. Importantly, there was no evidence that B-Raf V600 mutational status influenced melanoma cell response to these agents. Nuclear accumulation and/or induction of p53, p21, FOXO3a, STAT1 and BAD, and reduction of MCL-1 occurred in melanoma cells at time points prior to apoptosis as shown by increase in cleaved PARP and caspase 3 levels. PK studies were conducted in mice following oral administration of 10 mg/kg, to guide drug selection for our ongoing efficacy studies in murine melanoma models. KPT-185 showed limited bioavailability and systemic exposure, while KPT-276 and KPT-330 showed >50% bioavailability reaching Cmax >5µM. Conclusions: This study represents the first report of CRM1 inhibition in melanoma. These data indicate that the novel SINE compounds can effectively inhibit CRM1-mediated nuclear export and induce apoptosis in melanoma cells. KPT-330 is currently under development as orally bioavailable, small molecule inhibitors for a human clinical trial.


2019 ◽  
Vol 37 (15_suppl) ◽  
pp. e21005-e21005 ◽  
Author(s):  
Govind Warrier ◽  
Lilibeth Lanceta ◽  
Yoannis Imbert-Fernandez ◽  
Jason Alan Chesney

e21005 Background: Increased glucose metabolism is a hallmark of neoplastic cells that allows self-promotion of growth and survival. The enzyme 6-phosphofructo-2-kinase (PFKFB3) is an integral controller of glycolysis by promoting the synthesis of fructose 2,6-bisphosphonate (F2,6BP) which activates 6-phoshofructo-1-kinase (PFK-1), a rate-limiting enzyme and essential control point in the glycolytic pathway. Additionally, mitogen-activated protein kinase (MAPK) is a key signaling pathway in a number of cancers with mutations of the BRAF component, described most commonly in melanoma, resulting in constitutive activation of the MAPK pathway. We aim to demonstrate that vemurafenib, a BRAF inhibitor, has antiglycolytic activity in sensitive melanoma cell lines which may help guide development of future therapies with specific attention to PFKFB3 as a potential enzymatic target to decrease glycolytic flux thereby inhibiting tumor growth and survival. Methods: Vemurafenib sensitive and resistant variants of two separate human metastatic melanoma cell lines (451Lu and WM983) were treated with 3 mM Vemurafenib for 24 and 48 hours. Additionally, cells from aforementioned lines were probed for PFKFB3 after 24 hours of treatment with vemurafenib. Glycolysis was measured by incubating cells in complete media containing 1 mCi [5-3H]glucose for 60 minutes. [3H]H2O produced by glycolysis through enolase was measured. Results: A decrease in PFKFB3 protein expression was found in vemurafenib sensitive cells compared to controls but not in resistant cells after 24h treatment with 3 mM vemurafenib in both 451Lu and WM983 metastatic melanoma cell lines (n = 2). Treatment with vemurafenib led to decrease in glycolysis compared to untreated controls in both vemurafenib sensitive metastatic melanoma cell lines but not in resistant cell lines (n = 5). Additionally, there was a significant reduction in glycolysis in vemurafenib resistant WM983 at 48 hours compared to resistant untreated control. Conclusions: BRAF mutated metastatic melanoma cells showed decrease in PFKFB3 protein expression and decreased glycolysis after treatment with BRAF inhibitor vemurafenib. Future studies will focus on assessing metastatic melanoma cell viability and glycolytic activity after treatment with combination BRAF inhibition and PFKFB3 specific inhibition.


1996 ◽  
Vol 109 (7) ◽  
pp. 1957-1964 ◽  
Author(s):  
M. Goebeler ◽  
D. Kaufmann ◽  
E.B. Brocker ◽  
C.E. Klein

Recent evidence indicates that CD44, a multifunctional adhesion receptor involved in cell-cell as well as in cell-matrix interactions, plays an important role in local progression and metastasis of malignant tumors. We have studied a set of human melanoma cell lines differing in their metastatic potential in nude mice as well as in normal melanocytes for changes in CD44 expression and function. All melanocytes and melanoma cell lines tested highly expressed the CD44 standard form (CD44s, 85 kDa) but variants at low levels only. With respect to one of the CD44-associated functions primarily involved in tumor progression we found that two highly metastatic tumor cell lines, MV3 and BLM, showed fivefold higher migration rates towards hyaluronate than melanomas with low metastatic potential and normal melanocytes. Moreover, the highly metastatic cell lines expressed four- to sixfold higher levels of the CD44 epitope involved in hyaluronic acid-binding (monoclonal antibody Hermes-1) than less aggressive melanomas and melanocytes. Hermes-1 efficiently blocked haptotaxis to hyaluronate, supporting the functional relevance of this epitope. In contrast, expression levels of other CD44s epitopes recognized by seven different anti-CD44 monoclonal antibodies were unchanged, suggesting that the migratory behaviour of the cells depends on the formation of the hyaluronate-binding Hermes-1 epitope rather than on the overall CD44s surface expression, which was virtually identical in all melanoma and melanocyte cell lines tested. Differences in the accessibility of the hyaluronate-binding epitope defined by Hermes-1 correlated with the phosphorylation state of CD44s, probably reflecting different activation states of the receptor. Furthermore, immunoprecipitation and pulse/chase studies revealed a three- to fivefold increase in CD44 synthesis in the highly aggressive melanoma cells as compared to the other cell lines and the melanocytes, indicating a reduction of CD44 half-life and up-regulation of turnover. Moreover, highly aggressive melanoma cell lines were found to shed significant amounts of CD44 from the cell surface and to secrete its ligand hyaluronic acid, which may refer to an “autocrine' mechanism mediating melanoma cell motility.


2018 ◽  
Author(s):  
Su Wu ◽  
Anders M. Näär

AbstractWhile investigating the role played by de novo lipid (DNL) biosynthesis in cancer cells, we sought a medium condition that would support cell proliferation without providing any serum lipids. Here we report that a defined serum free cell culture medium condition containing insulin, transferrin and selenium (ITS) supports controlled study of transcriptional regulation of de novo fatty acid (DNFA) production and de novo cholesterol synthesis (DNCS) in melanoma cell lines. This lipid-free ITS medium is able to support continuous proliferation of several melanoma cell lines that utilize DNL to support their lipid requirements. We show that the ITS medium stimulates gene transcription in support of both DNFA and DNCS, specifically mediated by SREBP1/2 in melanoma cells. We further found that the ITS medium promoted SREBP1 nuclear localization and occupancy on DNFA gene promoters. Our data show clear utility of this serum and lipid-free medium for melanoma cancer cell culture and lipid-related areas of investigation.


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