PIK3CD Expression Research Articles

CircZNF532 promotes endothelial-to-mesenchymal transition in diabetic retinopathy by recruiting TAF15 to stabilize PIK3CD.

Endothelial-to-mesenchymal transition (EndMT) is a pivotal event in diabetic retinopathy (DR). This study explored the role of circRNA zinc finger protein 532 (circZNF532) in regulating EndMT in DR progression. Human retinal microvascular endothelial cells (HRMECs) were exposed to high glucose (HG) to induce the DR cell model. Actinomycin D-treated HRMECs were used to confirm the mRNA stability of phosphoinositide-3 kinase catalytic subunit δ (PIK3CD). The interaction between TATA-box-binding protein-associated factor 15 (TAF15) and circZNF532/PIK3CD was subsequently analyzed using RNA immunoprecipitation (RIP), RNA pull-down. It was found that HG treatment accelerated EndMT process, facilitated cell migration and angiogenesis, and enhanced PIK3CD and p-AKT levels in HRMECs, whereas si-circZNF532 transfection neutralized these effects. Further data showed that circZNF532 recruited TAF15 to stabilize PIK3CD, thus elevating PIK3CD expression. Following rescue experiments suggested that PIK3CD overexpression partially negated the inhibitory effect of circZNF532 silencing on EndMT, migration, and angiogenesis of HG-treated HRMECs. In conclusion, our results suggest that circZNF532 recruits TAF15 to stabilize PIK3CD, thereby facilitating EndMT in DR.

JAK3/STAT5 signaling-triggered upregulation of PIK3CD contributes to gastric carcinoma development.

Gastric cancer (GC) is one of the most common solid cancers with high incidence and mortality worldwide. Chronic gastritis and consequent inflammatory microenvironment is known as a major cause leading to gastric carcinogenesis. Here we report that PIK3CD that encodes p110δ, a catalytic subunit of the class IA PI3Ks, is overexpressed and tumorigenic in GC and associated with tumor inflammatory microenvironment. By investigating the data from TCGA database and our immunohistochemical staining and quantitative real-time PCR results from clinical samples, we found PIK3CD exhibits higher expression level in GC tissues compared with adjacent non-tumorous stomach tissues. Genetic silencing of PIK3CD in GC cells retards proliferation and migration in vitro and tumorigenicity and metastasis in vivo. In contrast, enhanced expression of PIK3CD promotes these phenotypes in vitro. Furthermore, pharmacological inhibition of PIK3CD could reduce GC cell viability and colony formation capacities. More importantly, we reveal a relevant mechanism that PIK3CD, but not PIK3CA and PIK3CB, is transcriptionally regulated by the pro-inflammatory IL2/JAK3/STAT5 axis and tumor-infiltrating immune cells such as lymphocytes. These observations may setup a new crosstalk between tumor inflammatory microenvironment, IL2/JAK3/STAT5 signaling and PI3K/AKT signaling. Targeting PIK3CD may be a promising therapy strategy for GC.

Mechanism of Wendan decoction in preventing obesity by regulating multiple signal pathway networks based on gene promoter methylation

ObjectiveTo investigate the potential mechanism of Wendan decoction in obesity by screening target genes with promoter region methylation changes and constructing a multiple signaling pathways network based on promoter methylation. MethodsThe methylation degree of Itgad, Col8a1, Adra2b, Jund, Rab2a, Wnt8b, Fzd9, B4galt7, Pik3cd, Creb1, Stard8, and Mmp1 in the abdominal adipose tissue of obese rats was determined using the Agena MassARRAY system. Western blot was performed to assess protein expression levels. Target genes were identified based on the methylation degree in the promoter region and protein expression. Enrichment analysis of signaling pathways was conducted to identify relevant target genes and obtain a multiple signaling pathway network associated with obesity. Core and terminal effector molecules in the pathway networks were selected as research targets for reverse transcription-polymerase chain reaction (RT-PCR) analysis. ResultsFour genes (Adra2b, Creb1, Itgad, and Pik3cd) showed a degree of promoter methylation consistent with their respective protein expression levels. Among them, Adra2b, Creb1, and Pik3cd expression increased, while that of Itgad decreased. Enrichment analysis revealed that Creb1 and Pik3cd were involved in 6 signaling pathways related to obesity: tumor necrosis factor (TNF) signaling pathway, growth hormone synthesis/secretion and action, adenosine 5′-monophosphate-activated protein kinase (AMPK) signaling pathway, relaxin signaling pathway, cyclic nucleotide (cAMP) signaling pathway, and phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt) signaling pathway. Subsequently, a multiple signaling pathways network was constructed based on promoter methylation. Key molecules including protein kinase B (AKT), mechanistic target of rapamycin complex 1 (mTORC1), and unc-51 like autophagy activating kinase 1 (ULK1), as well as terminal effector molecules interleukin-1β (IL-1β), interleukin-6 (IL-6), and chemokine (C-X-C motif) ligand 2 (CXCL2) were selected as research targets. Wendan decoction decreased the expressions of AKT, mTORC1, IL-1β, IL-6, and CXCL2 while up-regulating ULK1 expression. ConclusionThe mechanism of Wendan decoction in preventing obesity involves the regulation of multiple signaling pathways through the control of Creb1 and Pik3cd gene promoter methylation. However, the associated multi-path gene regulation mechanism in preventing obesity is complex. Thus, further exploration is needed to elucidate the role of methylation changes in this mechanism.

Comparative Transcriptome Analyses in Mantle Cell Lymphoma (MCL): Evidence of E2F1 As a Major Target in Aggressive Blastoid MCL Model

Background Mantle cell lymphoma (MCL) is a highly aggressive B-cell lymphoma characterized by the translocation t(11;14)(q13;q32) which triggers the dysregulation of the cyclin D1 by placing its coding gene CC1ND1 under the control of an immunoglobulin promoter. One of the major consequences of this molecular event is the disturbance of the cyclin D/Rb pathway leading to Rb inactivation and activation the elongation factor E2F1 mainly implicated in cell cycle progression. The mainstay of MCL therapies remains the chemo-immunotherapy followed by autologous transplantation but recently several novel therapies have been developed such as BTK inhibitors, Venetoclax, CDK4/6 inhibitors and more recently CAR-T therapies. However, patients with aggressive forms of MCL exhibit low response rates, requiring the identification of novel therapeutic targets. Materials and Methods We have previously generated an MCL cell line (UPN-1) from a patient with a blastoid variant of MCL presenting unique morphological and cytogenetics characteristics (M'kacher et al, Oncogene 2003). This cell line has been shown to harbor a TP53 mutation and a highly increased sensitivity to radiation despite the absence of functional p53. The molecular basis of this phenomenon has not been explored. In this work, we further characterized UPN-1 cell line using the Clarium S human microarray which has been compared to the gene expression profile of other existing MCL cell lines (GRANTA-519, JEKO-1, JVM-2, MAVEK-1, MINO, REC-1, SP-49, SP-53, Z-138). After mathematical correction, a supervised analysis was performed between triplicate samples of UPN-1 and a group constituted with all other MCL cell lines. We have then set up in vitro assays to determine the effect of a direct E2F1 inhibitor on the proliferative potential of UPN-1. Results The comparative transcriptome analyses revealed a list of 47 genes specifically upregulated in UPN-1. Unsupervised classification allowed to discriminate UPN-1 samples from other MCL cell lines based on the expression of these 47 genes. These data suggested a specific expression profile of UPN-1 as compared to other cell lines. Among the upregulated genes, E2F1 elongation factor was found to be highly upregulated in UPN-1 as compared to other MCL cell lines along with positive enrichment of E2F targets which are mainly implicated in cell cycle progression (Figure 1). Interestingly, UPN-1 has a low level of BCL-2 as compared to other MCL lines that could explain its radio sensitivity. However, other signaling pathways involved in the inhibition of apoptosis were found to be present in UPN-1 by geneset enrichment analysis. The expression of CDKN1A (p21), major cell cycle regulator and known as a marker of aggressive MCL, was found to be low in UPN-1. A repression of immune response pathway such as NFKB with low expression of NFKBIA was identified. Finally, the expression of PIK3CD which encodes for a therapeutic target in MCL (such as PI3KDelta inhibitor Idelalisib) was also significantly repressed in UPN-1 as compared to nine other MCL cell lines. To evaluate the effect of the direct inhibition of E2F1, we treated UPN-1 cells with a targeted E2F1 inhibitor 5‘-Deoxy-5‘-(methylthio)adenosine (MTA) which is a protein methylation inhibitor. MTT assays revealed a 50% reduction of proliferation at + 4 hours in comparison to the vehicle-treated conditions (P<0.0001).Annexin assays showed an increase in early apoptosis (36.6 %) at + 8 hours with subsequent rise in late apoptotic cells (64.5 %) observed after 24 hours of treatment. Interestingly, qRT-PCR analyses of MTA-treated cells exhibited a decrease in the expression of downstream factors associated with E2F1, such as RAD51, BRCA1, CDK2, CCNB2, RANBP1. Conclusions We report here for the first time the comparative transcriptome analysis of the unique aggressive blastoid MCL line UPN-1 as compared to other MCL lines described. This cell line exhibited a major upregulation of E2F1 expression and a down regulation of the cell cycle inhibitor CDKN1A(p21). The potential effects of the direct inhibition of E2F1 using the targeted inhibitor MTA demonstrated a reduction in cell proliferation and induction of apoptosis, suggesting the possibility of associating clinically acceptable E2F1 inhibition strategies to other current therapies.

Synergistic Effect of CK2 Inhibitor CX-4945 with HDACi Chidamide on Cell Proliferation Arrest and Apoptosis in Acute Myeloid Leukemia

Background CX-4945 is an ATP-competitive inhibitor of CK2, which is currently being used in clinical trials to treat various cancer types. Chidamide (CHI), a novel histone deacetylase inhibitor (HDACi), is now involved in the salvage treatment of relapsed/refractory acute myeloid leukemia (AML) in a clinical trial. The anti-leukemia effects of either single drug have been reported by inducing cell apoptosis through suppressing multi-oncogenic pathways in human tumor cells. However, whether and how the combination of the two drugs exerts synergistic anti-tumor effects remains undetermined. This study is to investigate the synergistic therapeutic effects of CX-4945 in combination with CHI in AML. Methods Cell Counting Kit-8 (CCK-8) cell proliferation assay, Annexin V apoptosis assay, and Propidium Iodide cell cycle assay were performed in AML cells in the presence of CX-4945 only, CHI only, CX-4945 + CHI, and vehicle control for 48h. RNA-seq was performed in U937 cells treated with CX-4945 and CHI, respectively; the differentially expressed genes (DEGs) were identified by R studio, and pathway enrichment of the DEGs was analyzed with Metascape online tool. Data were expressed as the mean ± standard deviation. Ordinary one-way ANOVA statistical analysis and Log-rank test was employed to determine the significant difference between groups. A synergistic effect was determined by the combination indices (CIs) with CalcuSyn software. Results The 50% inhibiting concentration (IC50) of CX-4945 on the U937 and THP-1 cell proliferation is 7.435±0.066μmol/L and 6.787±0.153μmol/L. The IC50 of CHI on the U937 and THP-1 cell proliferation is 3.009±0.32μmol/L and 3.782±0.239μmol/L, respectively. The combination of various doses of CHI with either IC50 or 1/2 IC50 of CX-4945 significantly decreases the cell viability of the cells versus single-drug control and CalcuSyn analysis showed the high synergistic therapeutic effects of CHI with CX-4945 (Fig.1A). The combination of (4µM) CHI with (8µM) CX-4945 significantly induced the G0/G1 cell cycle arrest (p <0.001, Fig.1B) and elevated the % of apoptotic cells (p <0.0001, Fig.1C) in the AML cells compared to either single drug alone. Moreover, the combination of (1.6µM) CHI with (8µM) CX-4945 significantly increased the % of apoptotic cells in the primary blasts from the AML patient versus either single drug alone (p<0.0001, Fig.1D). To further understand the underlying mechanism of the synergy, RNA-seq analysis was performed in U937 cells treated with either CHI or CX-4945, respectively (Fig.2A). The DEGs are achieved upon either drug treatment, and the 76 up-regulated and 411 down-regulated overlapped DEGs were identified (Fig.2B). Pathways analysis showed that the overlapped DEGs are enriched in cell cycle progress, apoptosis, and multiple oncogenic signaling including cMyc and PI3K/AKT signaling pathways (Fig.2C). cMyc and PI3K/AKT-dependent signaling pathways are involved in myeloid cell proliferation. Also, our ChIP-seq data indicated obvious Ikaros binding peaks in the promoter region of cMyc and PIK3CD and they are the direct targets of Ikaros (data not shown). cMyc and PIK3CD are at the top of the overlapped DEGs, indicating the critical roles of the cMyc and PIK3CD underlying the mechanism of the combination in AML. Indeed, the mRNA level of cMyc and PIK3CD is significantly down-regulated upon the combination treatment versus single drug control (Fig.2D or data not shown). Consistently, the mRNA level of PIK3CD is significantly higher expressed in AML patients versus that in bone marrow samples of the healthy donors (p<0.05, Fig.2E) and the AML patients with high PIK3CD high expression have shorter OS than that with low expression (p <0.05, Fig.2F). These data support the hypothesis that the combination exerts the anti-tumor effect by suppression of cMyc and PIK3CD expression in AML. Conclusions The combination of CHI and CX-4945 has a synergistic effect on cell proliferation arrest, apoptosis, and cell cycle arrest by suppressing cMyc and PI3K signaling in AML cells. Our data provide experimental evidence for the combination as a potential option for AML therapy. More pre-clinical studies will be explored for future clinical trials.

PIK3CD correlates with prognosis, epithelial–mesenchymal transition and tumor immune infiltration in breast carcinoma

BackgroundBreast carcinoma (BRCA) is one of the most common, fatal, and aggressive cancers, with increasing morbidity that has a major impact on human health. PIK3CD appears to have important roles in the beginning and advancement of various forms of human cancer, according to mounting data. However,the particular role and mechanism of PIK3CD in BRCA remains not fully identified.MethodologyThe Cancer Genome Atlas (TCGA, https://portal.gdc.cancer.gov/), Genotype-Tissue Expression (GTEx) data and the UCSC Xena browser (https://xenabrowser.net) data were used in this study’s initial pan-cancer analysis of PIK3CD expression and prognosis. Circular RNAs (circRNAs) that regulated the expression of PIK3CD were subsequently found using a combination of in silico investigations of expression, correlation, and survival. Measurements of PIK3CD expression and an analysis of the in vitro function of PIK3CD in BRCA cells were performed using real-time RT-PCR, Western blotting and Transwell assays.ResultsIn BRCA GLI2, RAB32, LAMB1, MGAT2, ITGA8, CHF, COL6A3 and PRRX1-miR-30b-5p axis was identified as the most likely upstream CircRNA-related route of PIK3CD. PIK3CD was correlated with the expression of EMT markers. The PIK3CD cDNA improved the capacity for invasion and migration. The expression of PIK3CD was linked to some of the m1A/m5C/m6A regulators. Additionally, it was discovered that the expression of PIK3CD was found to be highly connected to the expression of immunological checkpoints, immune cell biomarkers, and tumor immune cell invasion.ConclusionsOur findings reveal that PIK3CD expression is associated with prognosis, EMT, and tumor immune infiltration in BRCA patients.

USP14 Regulates ATF2/PIK3CD Axis to Promote Microvascular Endothelial Cell Proliferation, Migration, and Angiogenesis in Diabetic Retinopathy.

Diabetic retinopathy (DR) is one of the leading causes of blindness in diabetic patients. However, the pathogenesis of DR is complex, and no firm conclusions have been drawn so far. It has become a hot spot in ophthalmology research to deeply study the mechanism of DR pathological changes and find effective treatment options. Human retinal microvascular endothelial cells (HRMECs) were induced by high glucose (HG) to construct DR cell model. CCK-8 assay was used to detect the viability of HRMECs. Transwell assay was used to detect the migration ability of HRMECs. Tube formation assay was used to identify the tube formation ability of HRMECs. The expressions of USP14, ATF2 and PIK3CD were detected by Western blot analysis and qRT-PCR assay. Immunoprecipitation (IP) was used to ascertain the relationship of USP14 and ATF2. To explore the regulatory relationship between ATF2 and PIK3CD by dual-luciferase reporter gene assay and Chromatin immunoprecipitation (ChIP) assay. High glucose treatment promoted the proliferation, migration, and tube formation of HRMEC, and the expressions of USP14, ATF2 and PIK3CD were significantly up-regulated. USP14 or ATF2 knockdown inhibited HG-induced HRMECs proliferation, migration, and tube formation. USP14 regulated the expression of ATF2, and ATF2 promoted PIK3CD expression. PIK3CD overexpression attenuated the inhibitory effectiveness of USP14 knockdown on proliferation, migration and tube formation of DR cell model. Here, we revealed that USP14 regulated the ATF2/PIK3CD axis to promote proliferation, migration, and tube formation in HG-induced HRMECs.

Hepatic metabolomics combined with network pharmacology to reveal the correlation between the anti-depression effect and nourishing blood effect of Angelicae Sinensis Radix

Angelicae Sinensis Radix (AS) is reproted to exert anti-depression effect (ADE) and nourishing blood effect (NBE) in a rat model of depression. The correlation between the two therapeutic effects and its underlying mechanisms deserves further study. The current study is designed to explore the underlying mechanisms of correlation between the ADE and NBE of AS based on hepatic metabonomics, network pharmacology and molecular docking. According to metabolomics analysis, 30 metabolites involved in 11 metabolic pathways were identified as the potential metabolites for depression. Furthermore, principal component analysis and correlation analysis showed that glutathione, sphinganine, and ornithine were related to pharmacodynamics indicators including behavioral indicators and hematological indicators, indicating that metabolic pathways such as sphingolipid metabolism were involved in the ADE and NBE of AS. Then, a target-pathway network of depression and blood deficiency syndrome was constructed by network pharmacology analysis, where a total of 107 pathways were collected. Moreover, 37 active components obtained from Ultra Performance Liquid Chromatography-Triple-Time of Flight Mass Spectrometer (UPLC-Triple-TOF/MS) in AS extract that passed the filtering criteria were used for network pharmacology, where 46 targets were associated with the ADE and NBE of AS. Pathway enrichment analysis further indicated the involvement of sphingolipid metabolism in the ADE and NBE of AS. Molecular docking analysis indciated that E-ligustilide in AS extract exhibited strong binding activity with target proteins (PIK3CA and PIK3CD) in sphingolipid metabolism. Further analysis by Western blot verified that AS regulated the expression of PIK3CA and PIK3CD on sphingolipid metabolism. Our results demonstrated that sphingolipid metabolic pathway was the core mechanism of the correlation between the ADE and NBE of AS.

MiR-193-5p negatively regulates PIK3CD to promote crop fibrocyte proliferation in pigeon (Columba livia)

The crop of pigeon has specific characteristics as producing crop milk in the lactating period. However, the exact mechanisms underlying the regulation of crop lactation remain unclear. miRNAs, the essential regulators of gene expression, are implicated in various physiological and biological activities. In this study, we discovered a new miRNA that regulated phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit delta (PIK3CD) and crop fibrocyte proliferation. Results of the luciferase reporter assay suggested that miR-193-5p suppressed PIK3CD expression by targeting a conserved binding site in the 3'-untranslated region (UTR) of PIK3CD mRNA. MiR-193-5p promoted crop fibrocyte proliferation and migration, whereas PIK3CD inhibited these effects. These findings suggested an important regulatory role of miR-193-5p in crop fibrocyte proliferation, suggesting that miR-193-5p and PIK3CD might be important regulators of crop milk production.

Oncogenic potential of PIK3CD in glioblastoma is exerted through cytoskeletal proteins PAK3 and PLEK2

The Class IA phosphoinositide-3-kinase catalytic isoforms p110α, p110β, and p110δ have been implicated to play vital but overlapping roles in various cancers, including glioblastoma (GBM). We have previously shown that PIK3CD, encoding p110δ, is highly expressed in multiple glioma cell lines and involved in glioma cell migration and invasion. Based on the RNA sequencing data from The Cancer Genome Atlas (TCGA) database, we found the level of PIK3CD expression is significantly higher in GBM than WHO grade II and III gliomas and is closely related to poor survival. To further dissect the oncogenic roles of PIK3CD in glioma progression, we employed CRISPR/Cas9 to completely abrogate its expression in the GBM cell line U87-MG and have successfully isolated two knockout clones with different gene modifications. As expected, the knockout clones exhibited significantly lower migration and invasion capabilities when compared with their parental cells. Interestingly, knockout of PIK3CD also dramatically reduced the colony formation ability of the knockout cells. Further study revealed that PIK3CD deficiency could negate tumorigenesis in nude mice. To determine the downstream effect of PIK3CD depletion, we performed RT2 profiler PCR array of selected gene sets and found that knockout of PIK3CD impaired the activity of p-21 activated kinase 3 (PAK3) and pleckstrin 2 (PLEK2), molecules involved in cancer cell migration and proliferation. This explains why the glioma cells without the PIK3CD expression exhibited weaker oncogenic features. Further, RNAseq analysis of parent and knockout clones revealed that this interaction might happen through axonogenesis signaling pathway. Taken together, we demonstrated that PIK3CD could be a potential prognostic factor and therapeutic target for GBM patients.The present study elucidates the novel role of PIK3CD in glioblastoma (GBM) progression. Using in vitro and in vivo models of GBM, the authors show that GBM migration, invasion, proliferation and growth affect greatly when the activity of PIK3CD is disrupted by CRISPR/Cas9. Mechanistically, PIK3CD regulates the activity of p21 activated kinase (PPAK3) and plecstrin 2 (PLEK2) through axonogenesis pathway. The findings provide a novel mechanism of PIK3CD-mediated GBM development and suggest PIK3CD might be a target of GBM.

Association between single-nucleotide polymorphism in PIK3CD gene and litter size in Small Tail Han sheep

The p110δ isoform of the PI3K catalytic subunit (encoded by the PIK3CD gene) is a key component of the PI3K pathway for follicle growth in mammalian ovarian granulosa cells. Nevertheless, little is known about the association of its polymorphisms with ovine litter size. In this study, the distribution of different genotypes of two SNPs in the PIK3CD gene was calculated in more than forty sheep breeds, and the associations between SNPs and litter size in Small Tail Han (STH) sheep were also analyzed. Besides, the mRNA expression of the PIK3CD gene was also detected in some reproduction-related tissues. The results showed that the “A” allele frequency was higher in rs412889931 (g.41926327G > A) in a typical polytocous sheep breed (p < 0.01). The association's analysis showed rs412889931 was correlated with ovine fecundity as assessed by three parity litter sizes (p < 0.05). Finally, we found the expression of PIK3CD in the ovary had significant differences in different fecundity sheep breeds, indicating that SNP may regulate the litter size by influencing the PIK3CD gene expression. The present results demonstrated that rs412889931 could be used in the marker-assisted selection of the litter size in sheep breeding.

Abstract 1554: PI3Kγδ inhibitor combined with radiation enhances the antitumor immune effect of PD-1 blockade in syngenic murine breast cancer model and humanized patient-derived xenograft model

Abstract Purpose: Breast cancer is generally viewed as immunologically ‘cold', imposing an immune-suppressive tumor microenvironment (TME) and responding poorly to lone immune checkpoint blockade (ICB). As an adjunct to ICB, radiation therapy (RT) holds promise in terms of in situ tumor vaccination effect, although it is known to promote immune suppression, increasing regulatory T cells (Treg), myeloid-derived suppressor cells (MDSCs), and M2 tumor-associated macrophages (TAMs). It was our contention that combined use of RT and a PI3Kγδ inhibitor to combat immune suppression might enhance the efficacy of ICB. Methods: Murine breast cancer cells (4T1) were grown in both immune-competent and -deficient BALB/c mice, and tumors were irradiated by 3 fractions of 24 Gy. A PD-1 blockade (10 mg/kg) and a PI3Kγδ inhibitor (IPI145; 15 mg/kg) were then administered every other day for 2 weeks. We analyzed mRNA-sequencing data from humanized patient-derived xenograft (PDX) model to identify differentially activated immune-related pathways. Transcriptomic and clinical data were acquired from The Cancer Genome Atlas (TCGA) pan-cancer cohort, and the ‘xCell' deconvolution algorithm was used to profile immune cellular distributions at certain levels of PIK3C and PIK3CD expression. Results: In the immune-competent syngenic 4T1 murine tumor model, PD-1 blockade alone led to tumor hyperprogression, whereas a three-pronged strategy of PI3Kγδ inhibitor, RT, and PD-1 blockade significantly delayed primary tumor growth, boosted abscopal effect, and improved animal survival by comparison. The immune-deficient syngeneic 4T1 murine tumor model failed to show this synergism in delaying tumor growth and the abscopal effect. RT significantly increased not only CD8+cytotoxic T-cell fractions but also immune-suppressive Tregcells, MDSCs, and M2 TAMs. However, PI3Kγδ inhibitor significantly lowered proportions of Treg, MDSCs, and M2 TAMs, achieving dramatic gains in splenic, nodal, and tumor CD8+ T-cell populations after triple combination therapy. Triple combination therapy significantly delayed tumor growth in humanized PDX model as well. Analyses of RNA sequencing data of humanized PDX samples showed triple combination increased immune response pathways and increased CD8+ T-cell and decreased Treg and M2 TAM. In the TCGA pan-cancer cohort, higher tumor purity-adjusted Treg/CD8+T-cell and M2/M1 TAM ratios and worse overall patient survival were associated with high PIK3CG (PI3Kγ) or PIK3CD (PI3Kδ) gene expression. Conclusion: These findings collectively indicate that PI3Kγ and PI3Kδ are clinically relevant targets in an immunosuppressive TME. Combining PI3Kγδ inhibitor, RT, and PD-1 blockade may thus be a viable approach, helping to overcome the therapeutic resistance of immunologically cold tumors such as breast cancer. Citation Format: Min Guk Han, Bum-Sup Jang, Mi Hyun Kang, In Ah Kim. PI3Kγδ inhibitor combined with radiation enhances the antitumor immune effect of PD-1 blockade in syngenic murine breast cancer model and humanized patient-derived xenograft model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1554.

PI3Kγδ inhibitor combined radiation enhances the antitumor immune effect of PD-1 blockade in syngenic triple negative breast cancer models.

e13041 Background: Breast cancer is generally viewed as immunologically cold, imposing an immune-suppressive tumor microenvironment (TME) and responding poorly to lone immune checkpoint blockade (ICB). As an adjunct to ICB, radiation therapy (RT) holds promise in terms of in situ tumor vaccination effect, although it is known to promote immune suppression, increasing regulatory T cells (Treg), myeloid-derived suppressor cells (MDSCs), and M2 tumor-associated macrophages (TAMs). It was our contention that combined use of RT and a PI3Kγδ inhibitor to combat immune suppression might enhance the efficacy of ICB. Methods: Murine breast cancer cells (4T1) were grown in both immune-competent BALB/c mice, humanized patient-derived xenograft (PDX) were established, and both were irradiated by 3 fractions of 24 Gy. A PD-1 blockade (10 mg/kg) and a PI3Kγδ inhibitor (IPI145; 15 mg/kg) were then administered every other day for 2 weeks. Tumors from humanized PDX was sequenced to identify immune-related pathways and to profile infiltrated immune cells. Transcriptomic and clinical data were acquired from The Cancer Genome Atlas (TCGA) pan-cancer cohort, and the deconvolution algorithm was used to profile immune cellular distributions at certain levels (high vs. low) of PIK3Cand PIK3CD expression. Results: In the immune-competent syngenic 4T1 murine tumor model, PD-1 blockade alone led to tumor hyperprogression, whereas a three-pronged strategy of PI3Kγδ inhibitor, RT, and PD-1 blockade significantly delayed primary tumor growth, boosted abscopal effect, and improved animal survival. According to FACS analysis, RT significantly increased not only CD8+cytotoxic T-cell fractions but also immune-suppressive Tregcells, MDSCs, and M2 TAMs. However, PI3Kγδ inhibitor significantly lowered proportions of Treg, MDSCs, and M2 TAMs, achieving dramatic gains in splenic, nodal, and tumor CD8+ T-cell populations after triple combination therapy. There were significantly decreased tumor expressions of p-AKT, PD-L1, and HIF1α by PI3Kγδ inhibition. Triple combination therapy significantly delayed primary tumor growth in humanized PDX model as well and analyses of RNA sequencing data of humanized PDX samples showed decreased immune suppressive pathways with decreased and M2 macrophage and increased CD8+ T-cell by triple combination therapy. In the TCGA pan-cancer cohort, high Treg/CD8+T-cell and M2/M1 TAM ratios and poor overall patient survival was associated with high PIK3CG (PI3Kγ) or PIK3CD (PI3Kδ) gene expression. Conclusions: These findings collectively indicate that PI3Kγ and PI3Kδ are clinically relevant targets in an immunosuppressive TME. Combining PI3Kγδ inhibitor, RT, and PD-1 blockade may thus be a viable approach, helping to overcome the therapeutic resistance of immunologically cold tumors such as breast cancer.

Abstract PO-043: Radiation combined with PI3Kγδ inhibitor enhances the antitumor immune effect of PD-1 blockade in syngeneic murine breast cancer model and humanized patient-derived xenograft model

Abstract Purpose: Breast cancer is generally viewed as immunologically ‘cold’, imposing an immune-suppressive tumor microenvironment (TME) and responding poorly to lone immune checkpoint blockade (ICB). As an adjunct to ICB, radiation therapy (RT) holds promise in terms of in situ tumor vaccination effect, although it is known to promote immune suppression, increasing regulatory T cells (Treg), myeloid-derived suppressor cells (MDSCs), and M2 tumor-associated macrophages (TAMs). It was our contention that combined use of RT and a PI3Kγδ inhibitor to combat immune suppression might enhance the efficacy of ICB. Methods: Murine breast cancer cells (4T1) were grown in both immune-competent and -deficient BALB/c mice, and tumors were irradiated by 3 fractions of 24 Gy. A PD-1 blockade (10 mg/kg) and a PI3Kγδ inhibitor (IPI145; 15 mg/kg) were then administered every other day for 2 weeks. We analyzed mRNA-sequencing data from humanized patient-derived xenograft (PDX) model to identify differentially activated immune-related pathways. Transcriptomic and clinical data were acquired from The Cancer Genome Atlas (TCGA) pan-cancer cohort, and the ‘xCell’ deconvolution algorithm was used to profile immune cellular distributions at certain levels (high vs. low) of PIK3Cand PIK3CD expression. Results: In the immune-competent syngeneic 4T1 murine tumor model, PD-1 blockade alone led to tumor hyperprogression, whereas a three-pronged strategy of PI3Kγδ inhibitor, RT, and PD-1 blockade significantly delayed primary tumor growth, boosted abscopal effect, and improved animal survival by comparison. The immune-deficient syngeneic 4T1 murine tumor model failed to show this synergism in delaying tumor growth and the abscopal effect. According to FACS analysis, RT significantly increased not only CD8+cytotoxic T-cell fractions but also immune-suppressive Treg cells, MDSCs, and M2 TAMs. However, PI3Kγδ inhibitor significantly lowered proportions of Treg, MDSCs, and M2 TAMs, achieving dramatic gains in splenic, nodal, and tumor CD8+ T-cell populations after triple combination therapy. Triple combination therapy significantly delayed primary tumor growth in humanized PDX model as well and analyses of RNA sequencing data of humanized PDX samples showed triple combination decreased immune suppressive pathways with decreased M2 macrophage and increased CD8+ T-cell. In the TCGA pan-cancer cohort, higher tumor purity-adjusted Treg/CD8+T-cell and M2/M1 TAM ratios and worse overall patient survival were associated with high PIK3CG (PI3Kγ) or PIK3CD (PI3Kδ) gene expression. Conclusion: These findings collectively indicate that PI3Kγ and PI3Kδ are clinically relevant targets in an immunosuppressive TME. Combining PI3Kγδ inhibitor, RT, and PD-1 blockade may thus be a viable approach, helping to overcome the therapeutic resistance of immunologically cold tumors such as breast cancer. Citation Format: Min Guk Han, Bum-Sup Jang, Mi Hyun Kang, In Ah Kim. Radiation combined with PI3Kγδ inhibitor enhances the antitumor immune effect of PD-1 blockade in syngeneic murine breast cancer model and humanized patient-derived xenograft model [abstract]. In: Proceedings of the AACR Virtual Special Conference on Radiation Science and Medicine; 2021 Mar 2-3. Philadelphia (PA): AACR; Clin Cancer Res 2021;27(8_Suppl):Abstract nr PO-043.

LncRNA HOTAIRM1, miR-433-5p and PIK3CD function as a ceRNA network to exacerbate the development of PCOS

BackgroundCurrently, several non-coding RNAs (ncRNAs) were distinguished in polycystic ovarian syndrome (PCOS). This present study aims to explore the potential function of lncRNA HOTAIRM1/miR-433-5p/PIK3CD in ovarian granulosa cells.MethodsWe analyzed the expression profiles of HOTAIRM1, miR-433-5p and PIK3CD in PCOS samples by enquiring GEO database. GSEA was applied to enrich the pathways related to PCOS. The target association between HOTAIRM1 and miR-433-5p or the binding association between miR-433-5p and PIK3CD were assessed by online prediction tools and a dual luciferase reporter assay. qPCR and western blotting assays were used to detect PIK3CD expression after HOTAIRM1 and miR-433-5p treatment. The proliferation and apoptosis of ovarian granulosa cells were estimated by cell counting kit-8 and flow cytometry assays, respectively.ResultsThe expression profiles of HOTAIRM1 and PIK3CD were increased, whereas miR-433-5p was decreased in PCOS tissues. PIK3CD expression was positively regulated by HOTAIRM1 and negatively modulated by miR-433-5p. Overexpression of HOTAIRM1 reduced the proliferative ability and increased the apoptotic ability of granulosa cells, whereas upregulation of miR-433-5p or downregulation of PIK3CD reversed the effects of HOTAIRM1 on granulosa cells. Moreover, overexpression of miR-433-5 displayed a results with increasing proliferative ability and decreasing apoptotic ability, but upregulation of PIK3CD eliminated the function of miR-433-5p on granulosa cells.ConclusionsOur findings illustrated that HOTAIRM1 could sponge miR-433-5p to promote PIK3CD expression, thereby regulating the growth and apoptosis of granulose cells in PCOS.

Combined Radiation and PI3Kγδ Inhibitor Enhances Anti-Tumor Effect of PD-1 Blockade in Immune-competent Syngeneic Breast Cancer Model

Breast cancer is generally viewed as immunologically ‘cold’, imposing an immune-suppressive tumor microenvironment (TME) and responding poorly to lone immune checkpoint blockade (ICB). As an adjunct to ICB, radiation therapy (RT) holds promise in terms of in situ tumor vaccination effect, although it is known to promote immune suppression, increasing regulatory T cells (Treg), myeloid-derived suppressor cells (MDSCs), and M2 tumor-associated macrophages (TAMs). It was our contention that combined use of RT and a PI3Kγδ inhibitor to combat immune suppression might enhance the efficacy of ICB. Murine breast cancer cells (4T1) were grown in both immune-competent and -deficient BALB/c mice, and tumors were irradiated by 3 fractions of 24 Gy. A PD-1 blockade (10 mg/kg) and a PI3Kγδ inhibitor (IPI145; 15 mg/kg) were then administered every other day for 2 weeks. Fluorescence-activated cell sorting (FACS) and immunohistochemistry served to monitor subsequent changes in immune cell repertoire. We used mRNA-sequencing data of patient-derived breast cancer xenografts in a humanized NSG mouse model to analyze differentially expressed genes. Transcriptomic and clinical data were acquired from The Cancer Genome Atlas (TCGA) pan-cancer cohort, and a deconvolution algorithm (xCell) was used to profile immune cellular distributions at certain levels (high vs. low) of PI3Kγδ expression. In the immune-competent syngeneic 4T1 murine tumor model, PD-1 blockade alone led to tumor hyperprogression, whereas a three-pronged strategy of PI3Kγδ inhibitor, RT, and PD-1 blockade significantly delayed primary tumor growth, boosted abscopal effect, and improved animal survival by comparison. The immune-deficient syngeneic 4T1 murine tumor model failed to show this synergism in delaying tumor growth. According to FACS analysis, RT significantly increased not only CD8+cytotoxic T-cell fractions but also immune-suppressive Treg cells, MDSCs, and M2 TAMs. However, PI3Kγδ inhibitor significantly lowered proportions of Treg, MDSCs, and M2 TAMs, achieving dramatic gains in splenic, nodal, and tumor CD8+ T-cell populations after triple combination therapy. There was significantly decreased tumor expression of p-AKT, PD-L1, and HIF1α by PI3Kγδ inhibition. The analyses of RNAseq data of humanized PDX showed triple combination increased immune response pathways and increased CD8 T cell and decreased Treg and M2 macrophage shown by the Xcell deconvolution. In the TCGA pan-cancer cohort, higher tumor purity-adjusted Treg/CD8+T-cell and M2/M1 TAM ratios and worse overall patient survival were associated with high PIK3CG (PI3Kγ) or PIK3CD (PI3Kδ) expression. These findings collectively indicate that PI3Kγ and PI3Kδ are clinically relevant targets in an immunosuppressive TME. Combining PI3Kγδ inhibitor, RT, and PD-1 blockade may thus be a viable approach, helping to overcome the therapeutic resistance of immunologically cold tumors such as breast cancer.

The Mutational and Transcriptional Landscapes of Hepatocarcinogenesis in a Rat Model.

SummaryHepatocellular carcinoma (HCC) initiation is characterized by stepwise accumulation of molecular alterations, during which the early events are largely unknown. Here, we presented a comprehensive genomic and transcriptomic landscape at stages of hepatitis, cirrhosis, and HCC by using a diethylnitrosamine-induced rat HCC model. We observed the early occurrence of gene instability and aberrant cancer associated signaling pathways in liver hepatitis. We further characterized the progressive molecular changes during hepatocarcinogenesis, wherein the intense rivalry between tumor-suppressive and oncogenic strengths occurred in cirrhosis stage. Despite the significant pathological difference, mutation signatures and expression landscape are highly similar between hepatitis and cirrhosis stages. Furthermore, we identified PI3K-Akt signaling pathway as a key pathway in the process of hepatocarcinogenesis through integrative analysis, and PIK3CD is a potential biomarker indicating HCC recurrence. The dynamic immune response during hepatocarcinogenesis, such as continuous decline of monocytes, suggests an immunological intervention strategy beyond chemoprevention for liver cancer.

CiRS-7 functions as a ceRNA of RAF-1/PIK3CD to promote metastatic progression of oral squamous cell carcinoma via MAPK/AKT signaling pathways

PurposeRecent findings have shown that circRNA dysregulation was involved in the development of many types of cancer. However, our knowledge of circRNA in oral squamous cell carcinoma (OSCC) remains elusive. MethodsHere, we explored whether ciRS-7 could function as a ceRNA in promoting metastasis of OSCC via regulating miR-7 activity. The expression levels of ciRS-7 and miR-7 were examined in clinical samples and cell lines by qRT-PCR, and the effects of ectopic expression of ciRS-7 and miR-7 on cell proliferation, migration and invasion were assessed in vitro and in vivo. The effects of ciRS-7 on miR-7 activity were investigated by means of luciferase reporter assay, qRT-PCR and Western blot. In addition, the effects of miR-7 mediated ciRS-7 on the levels of MAPK/AKT signaling proteins were evaluated by Western blot. ResultsWe found that ciRS-7 was highly expressed in OSCC tissues and cell lines compared with normal counterparts. Ectopic expression of ciRS-7 significantly promoted OSCC cell proliferation, migration and invasion through in vitro and in vivo. Based on bioinformatics analysis, qRT-PCR, Western blot and luciferase reporter assays, we determined that ciRS-7 functioned as a sponge for miR-7, resulting in attenuation of miR-7 targets RAF-1 and PIK3CD, which are core components of the MAPK/AKT signaling pathways. Moreover, miR-7 correlated with perineural and lymphovascular invasion in OSCC patients. Further experiments demonstrated that ciRS-7 overexpression could attenuate the anti-tumor effects of miR-7 on OSCC cells. ConclusionsOur results suggested that ciRS-7 can interact directly with miR-7, resulting in upregulation of RAF-1/PIK3CD expression and enhancing metastatic progression of OSCC.

Abstract 1552: Single cell expression analysis of PIK3 genes to direct solid tumor treatment with the dual PI3K-δ,γ inhibitor duvelisib

Abstract Duvelisib is a dual PI3K-δ,γ inhibitor that targets malignant B and T cells in hematologic malignancies and modulates key non-malignant immune cells in the tumor microenvironment. PI3K-δ and PI3K-γ are thought to govern tumor immune modulation through reduction of immunosuppressive Tregs and myeloid cells in solid tumors (Ali, 2014, Kaneda, 2016; De Henau, 2016). Yet, a potential role of these isoforms in directly targeting cancer cells of solid tumors is not understood. Expression levels of PI3K-δ (PIK3CD) and PI3K-γ (PIK3CG) were analyzed in 9 major tumor types (BRCA, HNSCC, LUSC, PAAD, STAD, COAD, LUAD, SKCM and THCA), and it was found that PIK3CD reproducibly had higher expression levels than PIK3CG. For example, in head and neck squamous cell carcinoma (HNSCC), PIK3CD had a median expression of 9.51 RNA-Seq Expectation-Maximization (RSEM) log2 and PIK3CG had a median of 5.56 RSEM log2; each of which are higher than the levels in normal cells (8.40 RSEM log2 &amp; 5.38 RSEM log2, respectively) (FireBrowse). By clustering solid tumors into ′Hot′ (inflamed) and ′Cold′ subgroups with an inflammatory/immunosuppressive gene signature (Givechian, 2018; TCGA, n=1687); a correlation was observed between higher PIK3CD and PIK3CG expression in ′Hot′ (median ≈11 log2 Transcripts Per Million (TPM) &amp; ≈9.2 log2 TPM) compared to ′Cold′ tumors (median ≈9.4 log2 TPM &amp; ≈6.6 log 2 TPM). Using CIBERSORT deconvolution, most ′Hot′ cluster tumors contained higher fractions of CD8+ T cells, M1-type macrophages, and lower M2-type macrophages; with Tregs at similar abundances in both ′Hot′ and ′Cold′ clusters. To evaluate cellular distribution, single-cell RNA expression of PIK3C genes in a HNSCC dataset (Puram, 2017) was examined at &amp;gt;0.3 log2 TPM. PIK3CD and PIK3CG expression was observed in T cells (32% &amp; 11%, respectively), B cells (13% &amp; 56%), dendritic cells (15% &amp; 40%) and macrophages (24% &amp; 29%) in HNSCC tumors. PIK3A and PIK3B were less frequently expressed in macrophages (10% &amp; 17%) and T cells (3% &amp; 4%) than PIK3D. A significant proportion of the HNSCC cancer cells expressed PIK3CD (20%) and PIK3CB (27%), whereas PIK3CA (14%) and PIK3CG (0%) were less frequently expressed. Most individual tumors had cancer cells expressing PIK3CD (6%-63%; &amp;gt;50 cells/tumor). Importantly, PIK3CD expression was mostly mutually exclusive with PIK3CG, PIK3CA, and PIK3CB in the cancer cells. Cancer cells expressing PIK3CD showed striking co-associated differentially expressed genes (p&amp;lt;0.009). These results indicate that PI3Kδ expression is observed in both the immune cells which are fashioning the suppressive microenvironment and in cancer cells. These findings suggest an approach to identify patients for treatment guided by cell type expression of PI3K isoforms, and provide strategies for duvelisib use as monotherapy and in combinations with PD-1 checkpoint inhibitors and other agents. Citation Format: Samantha Hidy, Jonathan A. Pachter, David T. Weaver. Single cell expression analysis of PIK3 genes to direct solid tumor treatment with the dual PI3K-δ,γ inhibitor duvelisib [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1552.

Abstract 663: The dual PI3K-δ/PI3K-γ inhibitor duvelisib inhibits signaling and proliferation of solid tumor cells expressing PI3K-δ and/or PI3K-γ

Abstract Duvelisib is an oral, dual PI3K-δ,γ inhibitor that is FDA-approved for treatment of chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) and follicular lymphoma (FL) following ≥2 prior systemic therapies. In addition to targeting malignant B cells, duvelisib regulates key non-malignant immune cells in the tumor microenvironment (TME), including Tregs and immunosuppressive myeloid cells. However, direct effects of duvelisib on solid tumor cells have not been tested. Here, we used the GEPIA webserver to analyze the expression of PIK3CD [PI3K-δ] and PIK3CG [PI3K-γ] from the TCGA database. Whereas PIK3CG was highly expressed in hematological malignancies (log2 median transcript per million, TPM+1 &amp;gt; 2) but not in solid tumors, PIK3CD was highly expressed in hematological malignancies (log2TPM+1 = 5.1 in DLBCL) as well as in a number of solid tumors, including melanoma (log2TPM+1 = 4.4) and head and neck squamous cell carcinoma (HNSCC) (log2TPM+1 = 3.2). Further, PIK3CD was more highly expressed in melanoma and HNSCC human tumor samples compared to adjacent normal tissue, suggesting a potential tumorigenic role of PI3K-δ. We also checked the expression of PIK3CD in human tumor cell lines from the Cancer Cell Line Encyclopedia database and found that 57% and 22% of the melanoma and HNSCC cell lines, respectively, expressed high levels (log2TPM+1 &amp;gt; 2) of PIK3CD, while 7% of melanoma cell lines expressed high levels of PIK3CG. To assess possible direct effects of duvelisib on solid tumor cells, the growth inhibitory activity of duvelisib was evaluated across 7 melanoma and 3 HNSCC cell lines expressing high levels of PI3K-δ and/or PI3K-γ. Cell viability was measured after 72-hour treatment with duvelisib (0.5nM-10μM) and reported as growth inhibition (GI) at 1μM. Duvelisib showed strong anti-proliferative activity (50-100% GI) in 3 out of 7 melanoma cell lines and 1 out of 3 HNSCC cell lines, and moderate activity (15-50% GI) in 3 melanoma cell lines and an additional HNSCC cell line. Duvelisib inhibited PI3K pathway activity, as measured by p-AKT and c-myc, in all the cell lines in which strong anti-proliferative activity was observed. Taken together, these findings indicate that in addition to the established effects of duvelisib on malignant B cells and non-malignant immune cells of the TME, duvelisib can also directly inhibit signaling and proliferation of solid tumor cells expressing PI3K-δ and/or PI3K-γ, providing further rationale for clinical investigation of duvelisib for the treatment of solid tumors. Accordingly, the combination of duvelisib with pembrolizumab is currently being evaluated in patients with head and neck squamous cell carcinoma. Citation Format: SILVIA COMA, David T. Weaver, Jonathan A. Pachter. The dual PI3K-δ/PI3K-γ inhibitor duvelisib inhibits signaling and proliferation of solid tumor cells expressing PI3K-δ and/or PI3K-γ [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 663.