PURPOSE: PI3K signaling is a common feature of B-cell neoplasms, including chronic lymphocytic leukemia (CLL) and diffuse large B-cell lymphoma (DLBCL), and PI3K inhibitors have been introduced into the clinic. However, there remains a clear need to develop new strategies to target PI3K signaling. PI3K activity is countered by Src homology domain 2-containing inositol-5'-phosphatase 1 (SHIP1) and, here, we have characterized the activity of a novel SHIP1 activator, AQX-435, in preclinical models of B-cell malignancies. EXPERIMENTAL DESIGN: In vitro activity of AQX-435 was evaluated using primary CLL cells and DLBCL-derived cell lines. In vivo activity of AQX-435, alone or in combination with the Bruton's tyrosine kinase (BTK) inhibitor ibrutinib, was assessed using DLBCL cell line and patient-derived xenograft models. RESULTS: Pharmacologic activation of SHIP1 using AQX-435 was sufficient to inhibit anti-IgM-induced PI3K-mediated signaling, including induction of AKT phosphorylation and MYC expression, without effects on upstream SYK phosphorylation. AQX-435 also cooperated with the BTK inhibitor ibrutinib to enhance inhibition of anti-IgM-induced AKT phosphorylation. AQX-435 induced caspase-dependent apoptosis of CLL cells preferentially as compared with normal B cells, and overcame in vitro survival-promoting effects of microenvironmental stimuli. Finally, AQX-435 reduced AKT phosphorylation and growth of DLBCL in vivo and cooperated with ibrutinib for tumor growth inhibition. CONCLUSIONS: Our results using AQX-435 demonstrate that SHIP1 activation may be an effective novel therapeutic strategy for treatment of B-cell neoplasms, alone or in combination with ibrutinib.

• MeSH
• aktivátory enzymů farmakologie   MeSH
• apoptóza účinky léků   MeSH
• chronická lymfatická leukemie farmakoterapie   metabolismus   patologie   MeSH
• difúzní velkobuněčný B-lymfom farmakoterapie   metabolismus   patologie   MeSH
• fosfatidylinositol-3-kinasy chemie   metabolismus   MeSH
• fosfatidylinositol-3,4,5-trisfosfát-5-fosfatasy genetika   metabolismus   MeSH
• lidé MeSH
• myši inbrední NOD MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• protinádorové látky farmakologie   MeSH
• seskviterpeny farmakologie   MeSH
• signální transdukce MeSH
• xenogenní modely - testy protinádorové aktivity MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Phosphoinositides (PIs) are phosphorylated derivatives of phosphatidylinositol. They act as signaling molecules linked to essential cellular mechanisms in eukaryotic cells, such as cytoskeleton organization, mitosis, polarity, migration or invasion. PIs are phosphorylated and dephosphorylated by a large number of PI kinases and PI phosphatases acting at the 5-, 4- and 3- position of the inositol ring. PI 5-phosphatases i.e. OCRL, INPP5B, SHIP1/2, Synaptojanin 1/2, INPP5E, INPP5J, SKIP (INPP5K) are enzymes that dephosphorylate the 5-phosphate position of PIs. Several human genetic diseases such as the Lowe syndrome, some congenital muscular dystrophy and opsismodysplasia are due to mutations in PI phosphatases, resulting in loss-of-function. The PI phosphatases are also up or down regulated in several human cancers such as glioblastoma or breast cancer. Their cellular localization, that is dynamic and varies in response to stimuli, is an important issue to understand function. This is the case for two members of the PI 5-phosphatase SKIP and SHIP2. Both enzymes are in ruffles, plasma membranes, the endoplasmic reticulum, a situation that is unique for SKIP, and the nucleus. Following localization, PI 5-phosphatases act on specific cellular pools of PIs, which in turn interact with target proteins. Nuclear PIs have emerged as regulators of genome functions in different area of cell signaling. They often localize to nuclear speckles, as do several PI metabolizing kinases and phosphatases. We asked whether SKIP and SHIP2 could have an impact on nuclear PI(4,5)P2. In two glioblastoma cell models, lowering SKIP expression had an impact on nuclear PI(4,5)P2. In a model of SHIP2 deletion in MCF-7 cells, no change in nuclear PI(4,5)P2 was observed. Finally, we present evidence of an anti-tumoral role of SKIP in vivo, in xenografts using as model U87shSKIP cells.

• MeSH
• buněčné jádro enzymologie   genetika   MeSH
• endoplazmatické retikulum enzymologie   genetika   patologie   MeSH
• fosfatasy genetika   metabolismus   MeSH
• fosfatidylinositol-3,4,5-trisfosfát-5-fosfatasy genetika   metabolismus   MeSH
• glioblastom enzymologie   genetika   patologie   MeSH
• lidé MeSH
• MFC-7 buňky MeSH
• myši inbrední NOD MeSH
• myši SCID MeSH
• myši MeSH
• nádorové proteiny genetika   metabolismus   MeSH
• nádory prsu enzymologie   genetika   patologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Receptor tyrosine kinases (RTKs) form multiprotein complexes that initiate and propagate intracellular signals and determine the RTK-specific signalling patterns. Unravelling the full complexity of protein interactions within the RTK-associated complexes is essential for understanding of RTK functions, yet it remains an understudied area of cell biology. We describe a comprehensive approach to characterize RTK interactome. A single tag immunoprecipitation and phosphotyrosine protein isolation followed by mass-spectrometry was used to identify proteins interacting with fibroblast growth factor receptor 3 (FGFR3). A total of 32 experiments were carried out in two different cell types and identified 66 proteins out of which only 20 (30.3%) proteins were already known FGFR interactors. Using co-immunoprecipitations, we validated FGFR3 interaction with adapter protein STAM1, transcriptional regulator SHOX2, translation elongation factor eEF1A1, serine/threonine kinases ICK, MAK and CCRK, and inositol phosphatase SHIP2. We show that unappreciated signalling mediators exist for well-studied RTKs, such as FGFR3, and may be identified via proteomic approaches described here. These approaches are easily adaptable to other RTKs, enabling identification of novel signalling mediators for majority of the known human RTKs.

• MeSH
• adaptorové proteiny signální transdukční genetika   metabolismus   MeSH
• buňky NIH 3T3 MeSH
• cyklin-dependentní kinasy genetika   metabolismus   MeSH
• elongační faktor 1 genetika   metabolismus   MeSH
• endozomální třídící komplexy pro transport genetika   metabolismus   MeSH
• fosfatidylinositol-3,4,5-trisfosfát-5-fosfatasy genetika   metabolismus   MeSH
• fosfoproteiny genetika   metabolismus   MeSH
• fosforylace MeSH
• HEK293 buňky MeSH
• homeodoménové proteiny genetika   metabolismus   MeSH
• lidé MeSH
• mapování interakce mezi proteiny MeSH
• myši MeSH
• protein-serin-threoninkinasy genetika   metabolismus   MeSH
• proteomika metody   MeSH
• receptor fibroblastových růstových faktorů, typ 3 genetika   metabolismus   MeSH
• regulace genové exprese * MeSH
• signální transdukce genetika   MeSH
• stanovení celkové genové exprese MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Sustained activation of extracellular signal-regulated kinase (ERK) drives pathologies caused by mutations in fibroblast growth factor receptors (FGFRs). We previously identified the inositol phosphatase SHIP2 (also known as INPPL1) as an FGFR-interacting protein and a target of the tyrosine kinase activities of FGFR1, FGFR3, and FGFR4. We report that loss of SHIP2 converted FGF-mediated sustained ERK activation into a transient signal and rescued cell phenotypes triggered by pathologic FGFR-ERK signaling. Mutant forms of SHIP2 lacking phosphoinositide phosphatase activity still associated with FGFRs and did not prevent FGF-induced sustained ERK activation, demonstrating that the adaptor rather than the catalytic activity of SHIP2 was required. SHIP2 recruited Src family kinases to the FGFRs, which promoted FGFR-mediated phosphorylation and assembly of protein complexes that relayed signaling to ERK. SHIP2 interacted with FGFRs, was phosphorylated by active FGFRs, and promoted FGFR-ERK signaling at the level of phosphorylation of the adaptor FRS2 and recruitment of the tyrosine phosphatase PTPN11. Thus, SHIP2 is an essential component of canonical FGF-FGFR signal transduction and a potential therapeutic target in FGFR-related disorders.

• MeSH
• adaptorové proteiny signální transdukční genetika   metabolismus   MeSH
• aktivace enzymů MeSH
• extracelulárním signálem regulované MAP kinasy genetika   metabolismus   MeSH
• fosfatidylinositol-3,4,5-trisfosfát-5-fosfatasy genetika   metabolismus   MeSH
• fosforylace MeSH
• HEK293 buňky MeSH
• lidé MeSH
• MAP kinasový signální systém * MeSH
• membránové proteiny genetika   metabolismus   MeSH
• nádorové buněčné linie MeSH
• receptory fibroblastových růstových faktorů genetika   metabolismus   MeSH
• skupina kinas odvozených od src-genu genetika   metabolismus   MeSH
• tyrosinfosfatasa nereceptorového typu 11 genetika   metabolismus   MeSH
• vazba proteinů MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Metastasis of breast cancer cells to distant organs is responsible for ∼50% of breast cancer-related deaths in women worldwide. SHIP2 (also known as INPPL1) is a phosphoinositide 5-phosphatase for phosphatidylinositol (3,4,5)-trisphosphate [PI(3,4,5)P3] and phosphatidylinositol (4,5)-bisphosphate [PI(4,5)P2]. Here we show, through depletion of SHIP2 in triple negative MDA-MB-231 cells and the use of SHIP2 inhibitors, that cell migration appears to be positively controlled by SHIP2. The effect of SHIP2 on migration, as observed in MDA-MB-231 cells, appears to be mediated by PI(3,4)P2. Adhesion on fibronectin is always increased in SHIP2-depleted cells. Apoptosis measured in MDA-MB-231 cells is also increased in SHIP2-depleted cells as compared to control cells. In xenograft mice, SHIP2-depleted MDA-MB-231 cells form significantly smaller tumors than those formed by control cells and less metastasis is detected in lung sections. Our data reveal a general role for SHIP2 in the control of cell migration in breast cancer cells and a second messenger role for PI(3,4)P2 in the migration mechanism. In MDA-MB-231 cells, SHIP2 has a function in apoptosis in cells incubated in vitro and in mouse tumor-derived cells, which could account for its role on tumor growth determined in vivo.

• MeSH
• fosfatidylinositol-3,4,5-trisfosfát-5-fosfatasy antagonisté a inhibitory   genetika   metabolismus   MeSH
• inhibitory enzymů farmakologie   MeSH
• lidé MeSH
• metastázy nádorů MeSH
• MFC-7 buňky MeSH
• myši inbrední NOD MeSH
• myši SCID MeSH
• myši MeSH
• nádorové buňky kultivované MeSH
• nádory prsu patologie   MeSH
• pohyb buněk účinky léků   genetika   MeSH
• protinádorové látky farmakologie   MeSH
• xenogenní modely - testy protinádorové aktivity MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH