PI3Kδ implicates hematologic cancers and
solid tumors.
Alternative splicing is a post-transcriptional process for acquiring proteomic diversity in eukaryotic cells. Emerging evidence highlights the involvement of aberrant mRNA splicing in
cancer development / progression. PI3Kδ-L and PI3Kδ-S are overexpressed in advanced
solid tumors, such as
prostate, breast, colon,
lung and pancreatic cancers. Differential PI3Kδ and PI3Kδ-
S expression profiles were identified in a panel of
solid tumor cells. PI3Kδ inhibitor
Idelalisib and SRPK1 / 2 inhibitor SRPIN340 were employed to assess their efficacies on inhibiting the PI3Kδ-expressing solid tumors.
Idelalisib effectively inhibits PI3Kδ-L and its downstream signaling.
Idelalisib fails to inhibit PI3Kδ-S activity and its downstream signaling. SRPIN340 reverses the aberrant mRNA splicing, thereby inhibiting the downstream AKT / mTOR signaling.
In vitro functional assays further demonstrate that a combination of Idelalisib and SRPIN340 achieve a synergistic
drug effect, with drastically reduced
cell viabilities / growths of tumor spheroids, in inhibiting the advanced
tumor cells.