Gene/Protein
Disease
Symptom
Drug
Enzyme
Compound
Pivot Concepts:
Gene/Protein
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Target Concepts:
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Query: UMLS:C0699790 (
colon cancer
)
28,837
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Class I phosphoinositide 3-kinase (PI3K) generates phosphatidylinositol 3,4,5-trisphosphate (PtdIns(3,4,5)
P
3
) at the plasma membrane in response to growth factors, activating a signalling cascade that regulates many cellular functions including cell growth, proliferation, survival, migration and metabolism. The PI3K pathway is commonly dysregulated in human cancer, and drives tumorigenesis by promoting aberrant cell growth and transformation. PtdIns(3,4,5)
P
3
facilitates the activation of many pleckstrin homology (PH) domain-containing proteins including the serine/threonine kinase AKT. There are three AKT isoforms that are frequently hyperactivated in cancer through mutation, amplification or dysregulation of upstream regulatory proteins. AKT isoforms have converging and opposing functions in tumorigenesis. PtdIns(3,4,5)
P
3
signalling is degraded and terminated by phosphoinositide phosphatases such as phosphatase and tensin homologue (PTEN), proline-rich inositol polyphosphate 5-phosphatase (PIPP) (INPP5J) and
inositol polyphosphate 4-phosphatase type II
(INPP4B). PtdIns(3,4,5)
P
3
is rapidly hydrolysed by PIPP to generate phosphatidylinositol 3,4-bisphosphate (PtdIns(3,4)
P
2
), which is further hydrolysed by INPP4B to form phosphatidylinositol 3-phosphate (PtdIns3
P
). PtdIns(3,4)
P
2
and PtdIns3
P
are also important signalling molecules; PtdIns(3,4)
P
2
together with PtdIns(3,4,5)
P
3
are required for maximal AKT activation and PtdIns3
P
activates PI3K-dependent serum and glucocorticoid-regulated kinase (SGK3) signalling. Loss of
Pten, Pipp
or
Inpp4b
expression or function promotes tumour growth in murine cancer models through enhanced AKT isoform-specific signalling. INPP4B inhibits PtdIns(3,4)
P
2
-mediated AKT activation in breast and prostate cancer; however, INPP4B expression is increased in acute myeloid leukaemia (AML), melanoma and
colon cancer
where it paradoxically promotes cell proliferation, transformation and/or drug resistance. This review will discuss how PTEN, PIPP and INPP4B distinctly regulate PtdIns(3,4,5)
P
3
signalling downstream of PI3K and how dysregulation of these phosphatases affects cancer outcomes.
...
PMID:Regulation of PI3K effector signalling in cancer by the phosphoinositide phosphatases. 2808 69
