Delineating v-Src downstream effector pathways in transformed myoblasts

Ciuffini, Laura; Castellani, Loriana; Salvati, Erica; Galletti, S.; Falcone, Germana; Alemà, Stefano

doi:10.1038/sj.onc.1210665

Cited by 15 publications

(14 citation statements)

References 42 publications

(90 reference statements)

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“…Ras-N17 is a Ras mutant protein with substitution of asparagine (Asn) in place of serine (Ser) at position 17. This mutant inhibits the function of all endogenous cellular Ras proteins and prevents phosphorylation of mitogen-activated protein kinases and cell proliferation of myoblasts upon serum stimulation (31). We validated the efficacy of the Ad-rasN17 mutant in cardiomyocytes by finding the reduced AKT phosphorylation after serum stimulation (supplemental Fig.…”

Section: Inhibition Of Endogenous Of Mir-378 Increases Cardiomyocyte mentioning

confidence: 92%

A Cardiac-enriched MicroRNA, miR-378, Blocks Cardiac Hypertrophy by Targeting Ras Signaling

Nagalingam

Sundaresan

Gupta

et al. 2013

Journal of Biological Chemistry

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Background: miR-378 is a newly discovered cardiomyocyte-enriched miRNA. Results: By targeting Grb-2, miR-378 blocks activation of the hypertrophic signaling cascade and gene expression. Its deficiency contributes to the development of hypertrophy in a Ras activity-dependent manner. Conclusion: miR-378 is a negative regulator of cardiac hypertrophy. Significance: Cellular restoration of miR-378 will be beneficial in preventing adverse cardiac remodeling.Understanding the regulation of cardiomyocyte growth is crucial for the management of adverse ventricular remodeling and heart failure. MicroRNA-378 (miR-378) is a newly described member of the cardiac-enriched miRNAs, which is expressed only in cardiac myocytes and not in cardiac fibroblasts. We have previously shown that miR-378 regulates cardiac growth during the postnatal period by direct targeting of IGF1R (Knezevic, I., Patel, A., Sundaresan, N. R., Gupta, M. P., Solaro, R. J., Nagalingam, R. S., and Gupta, M. (2012) J. Biol. Chem. 287, 12913-12926). Here, we report that miR-378 is an endogenous negative regulator of cardiac hypertrophy, and its levels are down-regulated during hypertrophic growth of the heart and during heart failure. In primary cultures of cardiomyocytes, overexpression of miR-378 blocked phenylephrine (PE)-stimulated Ras activity and also prevented activation of two major growth-promoting signaling pathways, PI3K-AKT and Raf1-MEK1-ERK1/2, acting downstream of Ras signaling. Overexpression of miR-378 suppressed PE-induced phosphorylation of S6 ribosomal kinase, pERK1/2, pAKT, pGSK-3␤, and nuclear accumulation of NFAT. There was also suppression of the fetal gene program that was induced by PE. Experiments carried out to delineate the mechanism behind the suppression of Ras, led us to identify Grb2, an upstream component of Ras signaling, as a bona fide direct target of miR-378-mediated regulation. Deficiency of miR-378 alone was sufficient to induce fetal gene expression, which was prevented by knocking down Grb2 expression and blocking Ras activation, thus suggesting that miR-378 interferes with Ras activation by targeting Grb2. Our study demonstrates that miR-378 is an endogenous negative regulator of Ras signaling and cardiac hypertrophy and its deficiency contributes to the development of cardiac hypertrophy.Cardiac hypertrophy is an adaptive response of myocytes to increased workload that often develops as a consequence of hypertension or valvular heart diseases (1, 2). Because adult cardiomyocytes are unable to divide, they respond to growth stimuli by increasing their cell size, a process known as hypertrophy. During hypertrophy, myocytes not only grow in size but also add sarcomeres and induce the expression of a group of genes, which are usually expressed during fetal heart development. These changes are initially considered as compensatory to manage the increased workload on the heart; however, prolonged hypertrophy leads to pathological ventricular remodeling, which is an established precursor for heart failure. In recent years,...

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Section: Inhibition Of Endogenous Of Mir-378 Increases Cardiomyocyte mentioning

confidence: 92%

A Cardiac-enriched MicroRNA, miR-378, Blocks Cardiac Hypertrophy by Targeting Ras Signaling

Nagalingam

Sundaresan

Gupta

et al. 2013

Journal of Biological Chemistry

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“…No RO5126766-related cardiovascular disorders or rhabdomyolysis were observed. As the RAS/RAF/MEK (MAPK/ERK) pathway is at the centre of muscle signalling networks (40)(41)(42)(43), a direct role of MEK inhibition in CPK elevation cannot be excluded; however, to date, CPK elevations have not been commonly reported with other MEK and BRAF inhibitors. High exposure at steady state was significantly associated with an increased blood CPK.…”

Section: Discussionmentioning

confidence: 99%

First-in-Human, Phase I Dose-Escalation Study of the Safety, Pharmacokinetics, and Pharmacodynamics of RO5126766, a First-in-Class Dual MEK/RAF Inhibitor in Patients with Solid Tumors

Martinez-García

Banerji

Albanell

et al. 2012

Clinical Cancer Research

143

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Purpose: This phase I study assessed the maximum tolerated dose (MTD), dose-limiting toxicities (DLT), safety, pharmacokinetics, pharmacodynamics, and clinical activity of the first-in-class dual MEK/RAF inhibitor, RO5126766.Experimental Design: Initial dose-escalation was conducted using once daily dosing over 28 consecutive days in 4-week cycles. Further escalation was completed using 2 intermittent dosing schedules [7 days on treatment followed by 7 days off (7on/7off); 4 days on treatment followed by 3 days off (4on/3off)].Results: Fifty-two patients received RO5126766 at doses of 0.1 to 2.7 mg once daily, 2.7 to 4.0 mg (4 on/3 off), or 2.7 to 5.0 mg (7 on/7 off). The most common DLTs were elevated creatine phosphokinase (CPK) and blurred vision. The MTD for each dosing schedule was 2.25 mg once daily, 4.0 mg (4 on/3 off), and 2.7 mg (7 on/7 off). The dose/schedule recommended for phase II (RP2D) investigation was 2.7 mg (4 on/3 off). Frequent adverse events included rash-related disorders (94.2%), elevated CPK (55.8%), and diarrhea (51.9%). C max occurred 1 to 2 hours after dosing and mean terminal half-life was approximately 60 hours. Pharmacodynamic changes included reduced ERK phosphorylation, an increase in apoptosis in tumor tissue, and a reduction in fluorodeoxyglucose (FDG) uptake after 15 days of dosing. Three partial responses were seen: two in BRAF-mutant melanoma tumors and one in an NRAS-mutant melanoma.Conclusion: This first-in-human study shows that oral RO5126766 has manageable toxicity, a favorable pharmacokinetic/pharmacodynamic profile, and encouraging preliminary antitumor activity in this population of heavily pretreated patients, achieving tumor shrinkage in around 40% of patients across all dose levels and all tumor types.

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“…The mechanism behind the observed CPK elevation remains unknown at present. A direct role of MEK inhibition cannot be excluded as the MAPK pathway plays a key role in regulation of muscle cell signaling (24)(25)(26)(27).…”

Section: Discussionmentioning

confidence: 99%

Phase I Dose-Escalation Study of the Safety, Pharmacokinetics, and Pharmacodynamics of the MEK Inhibitor RO4987655 (CH4987655) in Patients with Advanced Solid Tumors

Leijen

Middleton

Tresca

et al. 2012

Clinical Cancer Research

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Purpose: This phase I study of the mitogen-activated protein/extracellular signal-regulated kinase inhibitor RO4987655 (CH4987655) assessed its maximum tolerated dose (MTD), dose-limiting toxicities (DLT), safety, pharmacokinetic/pharmacodynamic profile, and antitumor activity in patients with advanced solid tumors.Patients and Methods: An initial dose escalation was conducted using a once-daily dosing schedule, with oral RO4987655 administered at doses of 1.0 to 2.5 mg once daily over 28 consecutive days in 4-week cycles. Doses were then escalated from 3.0 to 21.0 mg [total daily dose (TDD)] using a twice-daily dosing schedule.Results: Forty-nine patients were enrolled. DLTs were blurred vision (n ¼ 1) and elevated creatine phosphokinase (n ¼ 3). The MTD was 8.5 mg twice daily (TDD, 17.0 mg). Rash-related toxicity (91.8%) and gastrointestinal disorders (69.4%) were the most frequent adverse events. The pharmacokinetic profile of RO4987655 showed dose linearity and a half-life of approximately 4 hours. At the MTD, target inhibition, assessed by suppression of extracellular signal-regulated kinase phosphorylation in peripheral blood mononuclear cells, was high (mean 75%) and sustained (90% of time >IC 50 ). Of the patients evaluable for response, clinical benefit was seen in 21.1%, including two partial responses (one confirmed and one unconfirmed). 79.4% of patients showed a reduction in fluorodeoxyglucose uptake by positron emission tomography between baseline and day 15.Conclusion: In this population of heavily pretreated patients, oral RO4987655 showed manageable toxicity, a favorable pharmacokinetics/pharmacodynamics profile, and promising preliminary antitumor activity, which has been further investigated in specific populations of patients with RAS and/or RAF mutation driven tumors.

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Delineating v-Src downstream effector pathways in transformed myoblasts

Cited by 15 publications

References 42 publications

A Cardiac-enriched MicroRNA, miR-378, Blocks Cardiac Hypertrophy by Targeting Ras Signaling

A Cardiac-enriched MicroRNA, miR-378, Blocks Cardiac Hypertrophy by Targeting Ras Signaling

First-in-Human, Phase I Dose-Escalation Study of the Safety, Pharmacokinetics, and Pharmacodynamics of RO5126766, a First-in-Class Dual MEK/RAF Inhibitor in Patients with Solid Tumors

Phase I Dose-Escalation Study of the Safety, Pharmacokinetics, and Pharmacodynamics of the MEK Inhibitor RO4987655 (CH4987655) in Patients with Advanced Solid Tumors

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