Synergistic cell growth inhibition by the combination of amrubicin and Akt-suppressing tyrosine kinase inhibitors in small cell lung cancer cells: Implication of c-Src and its inhibitor

Ueda, Yuki; Igishi, Tadashi; Hashimoto, Kiyoshi; Suyama, Hisashi; Araki, Koji; Sumikawa, Takashi; Takeda, Kazuhisa; Nakazaki, Hirofumi; Matsunami, Keiji; Kodani, Masahiro; Shigeoka, Yasushi; Matsumoto, Shingo; Shimizu, Eiji

doi:10.3892/ijo_00000195

“…Following treatment with 50 nM Dasatinib, phosphorylated SFK signal was again virtually completely lost, however Akt phosphorylation was largely unaffected (Figure 4.2). This is the first time that a disconnect between the EGFstimulated activation of Akt and the functional requirement for SFKs has been shown, as most previous studies using SFK inhibitors report a loss of Akt activation following Src inhibition (Kassenbrock et al, 2002;Ueda et al, 2009). However, these previous studies didn't investigate low dose treatment of SFK inhibitors, therefore the effects they observed with SFK inhibitor may have potentially been driven by off-target effects of the drug including inhibition of EGFR phosphorylation or membrane traffic dynamics (Nautiyal et al, 2009;Sorkina et al, 2002 (Wilde et al, 1999).…”

Section: Regulation Of Pi3k/akt Signaling By Fyn and Tom1l1mentioning

confidence: 62%

Specialized Clarthrin-Enriched Signaling Nanodomains Control Epidermal Growth Factor Receptor Signaling At The Plasma Membrane

Lucarelli¹

2021

Preprint

0

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The Epidermal Growth Factor (EGF) Receptor (EGFR) is a key receptor tyrosine kinase that controls many facets of cell physiology, including proliferation, survival and migration. EGF binding to EGFR elicits receptor phosphorylation and membrane recruitment and phosphorylation of Gab1 followed by activation of phosphatidylinositol-3-kinase (PI3K), leading to Akt phosphorylation and activation. Concomitantly upon ligand binding, EGFR is simultaneously is recruited to clathrin-coated pits (CCPs), eventually leading to receptor endocytosis. We previously uncovered that perturbation of clathrin, but not of receptor endocytosis, impairs EGF-stimulated activation of Akt signaling. Moreover, we found that some key EGFR signaling intermediates such as phosphorylated Gab1 are enriched with a subset of CCPs. We thus proposed that in addition to their well- known function as endocytic portals, some CCPs have a direct role in controlling EGFR signaling at the plasma membrane prior to receptor internalization. How CCPs and clathrin may directly control EGFR signaling at the plasma membrane prior to receptor endocytosis had remained poorly understood, which I have now examined here. I uncovered that perturbations of TOM1L1 (a clathrin-binding regulator of Src-family kinases) and the TOM1L1-binding Src-family kinase Fyn impaired EGF-stimulated Akt phosphorylation, similarly to the effects of clathrin perturbations. A similar requirement for an additional cytosolic kinase Ack1 was also found. Using total internal reflection fluorescence microscopy and automated image analysis, we found that TOM1L1, Fyn, and Ack1 are enriched within a subset of CCPs, and that those that house EGFR are also those that preferentially contain Fyn or Ack1. Perturbation of TOM1L1 prevented Fyn recruitment to CCPs, and mutants of TOM1L1 defective in Fyn binding or clathrin binding abrogated Akt phosphorylation downstream of EGF stimulation. Importantly, TOM1L1- or Fyn-positive CCPs exhibit unique properties, such as distinct lifetimes, size, and recruitment of endocytic accessory proteins. Thus, these results indicate that a subset of CCPs become specialized signaling-capable structures by enrichment with key signaling regulators to control EGFR signaling, a phenomenon required for subsequent Akt activation. Given the importance of EGFR in driving growth and survival of certain types of cancer, obtaining a better understanding of how CCPs organize key EGFR signals in space and time within the PM may lead to the development of novel anti-cancer treatments.

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“…Following treatment with 50 nM Dasatinib, phosphorylated SFK signal was again virtually completely lost, however Akt phosphorylation was largely unaffected (Figure 4.2). This is the first time that a disconnect between the EGFstimulated activation of Akt and the functional requirement for SFKs has been shown, as most previous studies using SFK inhibitors report a loss of Akt activation following Src inhibition (Kassenbrock et al, 2002;Ueda et al, 2009). However, these previous studies didn't investigate low dose treatment of SFK inhibitors, therefore the effects they observed with SFK inhibitor may have potentially been driven by off-target effects of the drug including inhibition of EGFR phosphorylation or membrane traffic dynamics (Nautiyal et al, 2009;Sorkina et al, 2002 (Wilde et al, 1999).…”

Section: Regulation Of Pi3k/akt Signaling By Fyn and Tom1l1mentioning

confidence: 62%

Specialized Clarthrin-Enriched Signaling Nanodomains Control Epidermal Growth Factor Receptor Signaling At The Plasma Membrane

Lucarelli¹

2021

Preprint

0

View full text Add to dashboard Cite

The Epidermal Growth Factor (EGF) Receptor (EGFR) is a key receptor tyrosine kinase that controls many facets of cell physiology, including proliferation, survival and migration. EGF binding to EGFR elicits receptor phosphorylation and membrane recruitment and phosphorylation of Gab1 followed by activation of phosphatidylinositol-3-kinase (PI3K), leading to Akt phosphorylation and activation. Concomitantly upon ligand binding, EGFR is simultaneously is recruited to clathrin-coated pits (CCPs), eventually leading to receptor endocytosis. We previously uncovered that perturbation of clathrin, but not of receptor endocytosis, impairs EGF-stimulated activation of Akt signaling. Moreover, we found that some key EGFR signaling intermediates such as phosphorylated Gab1 are enriched with a subset of CCPs. We thus proposed that in addition to their well- known function as endocytic portals, some CCPs have a direct role in controlling EGFR signaling at the plasma membrane prior to receptor internalization. How CCPs and clathrin may directly control EGFR signaling at the plasma membrane prior to receptor endocytosis had remained poorly understood, which I have now examined here. I uncovered that perturbations of TOM1L1 (a clathrin-binding regulator of Src-family kinases) and the TOM1L1-binding Src-family kinase Fyn impaired EGF-stimulated Akt phosphorylation, similarly to the effects of clathrin perturbations. A similar requirement for an additional cytosolic kinase Ack1 was also found. Using total internal reflection fluorescence microscopy and automated image analysis, we found that TOM1L1, Fyn, and Ack1 are enriched within a subset of CCPs, and that those that house EGFR are also those that preferentially contain Fyn or Ack1. Perturbation of TOM1L1 prevented Fyn recruitment to CCPs, and mutants of TOM1L1 defective in Fyn binding or clathrin binding abrogated Akt phosphorylation downstream of EGF stimulation. Importantly, TOM1L1- or Fyn-positive CCPs exhibit unique properties, such as distinct lifetimes, size, and recruitment of endocytic accessory proteins. Thus, these results indicate that a subset of CCPs become specialized signaling-capable structures by enrichment with key signaling regulators to control EGFR signaling, a phenomenon required for subsequent Akt activation. Given the importance of EGFR in driving growth and survival of certain types of cancer, obtaining a better understanding of how CCPs organize key EGFR signals in space and time within the PM may lead to the development of novel anti-cancer treatments.

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Dasatinib: A potent SRC inhibitor in clinical development for the treatment of solid tumors

Araujo

¹

,

Logothetis²

2010

Cancer Treatment Reviews

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SRC is a tyrosine kinase that plays a role in oncogenic, invasive and bone-metastatic processes. It has therefore been prioritized as a candidate therapeutic target in patients with solid tumors. Several SRC inhibitors are now in development, of which dasatinib has been most explored. Preclinical studies in a wide variety of solid tumor cell lines, including prostate, breast and glioma, have shown that that dasatinib acts as a cytostatic agent, inhibiting the processes of cell proliferation, invasion and metastasis. Dasatinib also inhibits the activity of osteoclasts, which have a major role in the development of metastatic bone lesions. Dasatinib has additive or synergistic activity in combination with a number of other agents, including cytotoxic agents and targeted therapies, providing a rationale for combination treatment in a clinical setting. Emerging clinical data with dasatinib support experimental observations, with preliminary phase 1 and 2 data demonstrating activity, both as a single agent and as combination therapy, in a range of solid tumors. Future clinical trials will further assess the clinical value of SRC inhibition with dasatinib.

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Synergistic cell growth inhibition by the combination of amrubicin and Akt-suppressing tyrosine kinase inhibitors in small cell lung cancer cells: Implication of c-Src and its inhibitor

Cited by 10 publications

References 25 publications

Specialized Clarthrin-Enriched Signaling Nanodomains Control Epidermal Growth Factor Receptor Signaling At The Plasma Membrane

Specialized Clarthrin-Enriched Signaling Nanodomains Control Epidermal Growth Factor Receptor Signaling At The Plasma Membrane

Specialized Clarthrin-Enriched Signaling Nanodomains Control Epidermal Growth Factor Receptor Signaling At The Plasma Membrane

Dasatinib: A potent SRC inhibitor in clinical development for the treatment of solid tumors

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