PI3Kα, PI3Kβ, and PI3Kδ isoforms. BAY1082439 is a selective PI3K inhibitor with equal potency against these three isoforms. [2]

BAY1082439 is a highly selective PI3Kα/α balance inhibitor. BAY1082439 exhibits an IC50 ratio of 1:3 in PI3Kα (4.9 nM) versus PI3Kα (15.0 nM) biochemical studies and is over 1000-fold selective for mTOR kinase [1]. BAY1082439 (0.1-1 μM; 72 hours) effectively inhibits PTEN-deficient prostate cancer cells, surpassing specific inhibitors of PI3Kα and/or PI3Kβ [2].

---

In PTEN-null human prostate cancer cell lines (PC3 and LNCaP), BAY1082439 effectively inhibited cell growth after 72 hours of treatment, blocking the G1/S cell cycle transition and inducing apoptosis. [2]
In isogenic PC3 PTEN-WT and PTEN-null cells, PTEN-null cells were three orders of magnitude more sensitive to BAY1082439 than WT cells. [2]
In both human prostate cancer cell lines (PC3, LNCaP) and mouse cell lines derived from CP mice (CaP8, CaP2), BAY1082439 prevented the feedback activation of the PI3K pathway and the rebound AKT phosphorylation seen with the PI3Kβ-selective inhibitor TGX-221. [2]
BAY1082439 demonstrated equal potency to inhibit cell growth as the combination of the PI3Kα-specific inhibitor BYL-719 and the PI3Kβ-specific inhibitor TGX-221. [2]
In epithelial, EMT, and mesenchymal-like cancer cells isolated from CPK prostate tissue, the PI3Kδ isoform (Pik3cd) was upregulated in EMT and mesenchymal-like cells. Correspondingly, these subpopulations were more sensitive to the PI3Kδ inhibitor CAL-101 than the epithelial subpopulation. BAY1082439 effectively inhibited tumor cell growth in all three cell subpopulations with comparable activity to the combination of PI3Kα, β, and δ inhibitors (BYL-719, TGX-221, and CAL-101). [2]
In vitro, BAY1082439 was more effective at inhibiting the growth of freshly isolated splenic B cells compared to the PI3Kδ-specific inhibitor CAL-101, while the mTOR inhibitor rapamycin had no obvious effect. [2]

The oral medication BAY1082439 (75 mg/kg; once daily for 4 weeks) is useful in stopping the progression of prostate cancer that lacks PTEN [2].

---

In the Pten conditional knockout mouse model (CP mice), oral administration of BAY1082439 at 75 mg/kg/day for 4 weeks (starting at 6 weeks of age) significantly decreased tumor size and P-AKT staining, nearly restored normal luminal architecture, and significantly reduced Ki67-positive cells compared to vehicle controls. No local invasion was observed. [2]
In a PC3 xenograft model in nude mice, BAY1082439 treatment significantly inhibited human prostate cancer growth compared to vehicle controls. [2]
In the CPK mouse model (Pten-null with Kras mutation), treatment with BAY1082439 (75 mg/kg/day for 4 weeks) resulted in significant reduction in prostate tumor weight. While vehicle-treated mice developed poorly differentiated invasive carcinoma with clear EMT regions, BAY1082439-treated mice had prostatic intraepithelial neoplasia (PIN) lesions with intact smooth muscle actin staining and no obvious EMT regions. [2]
In castrated CP mice (CRPC model), BAY1082439 treatment led to significant inhibition of the PI3K pathway (assessed by P-AKT level) and tumor cell proliferation (Ki67 IHC), resulting in significant reduction in tumor weight compared to vehicle-treated castrated mice. [2]
In castrated CP mice, BAY1082439 treatment led to significantly decreased tumor-infiltrating B cells (B220-positive), decreased expression of the B cell chemokine Cxcl13, and reduced mRNA levels of B cell-released lymphotoxin-α and -β (Lta and Ltb) in the tumor remnants. Furthermore, P-STAT3 levels were significantly reduced in the prostates of BAY1082439-treated castrated mice. [2]

Cell viability assay[2]
Cell Types: PC3 and LNCaP cells (PTEN-deleted human prostate cancer cell line)
Tested Concentrations: 0.1, 0.33, 1, 3.3, 10 μM
Incubation Duration: 72 hrs (hours)
Experimental Results: Effective inhibition of cell growth by blocking G1 /S cell cycle transition and by inducing apoptosis.

---

Cell culture: LNCaP, PC3, CaP2, CaP8, and CPKV cell lines were cultured. PC3 PTEN-WT and PTEN-null isogenic cells were also used. Splenic cells were isolated and cultured in RPMI-1640 medium with 10% FBS and stimulated with LPS and anti-CD40. [2]
In vitro drug treatment assays: Cell growth, apoptosis, and cell cycle were determined using commercial kits. For Lta/Ltb assays, cells were plated and treated with Lta/Ltb and flutamide. After 5 days, total cell number was counted. [2]
Protein and RNA analysis: Protein was extracted using SDS-lysis buffer and separated by SDS-PAGE. Western blot analysis was performed with antibodies against P-AKT, AKT, P-S6, S6, P-ERK1/2, ERK, and Actin. RNA was extracted, reverse transcribed, and quantitative PCR was performed using SYBR Green. [2]
Histology and IHC Analysis: Tissue sections were subjected to hematoxylin and eosin (HE) staining and immunohistochemistry (IHC) using antibodies against AR, Vimentin, E-Cadherin, P-AKT (S473), P-STAT3 (Tyr705), CD19, Ki67, αSMA, and B220. [2]
Tissue Dissociation, Single-cell Suspension, and FACS analysis/sorting: Single-cell suspensions from prostate tumors and spleen were prepared. FACS analysis was performed to separate epithelial, EMT, and mesenchymal-like cancer cells from CPKV prostate tumor tissue. [2]
Methylation profile analysis: Reduced representation bisulfite sequencing (RRBS) libraries were prepared from separated epithelial, EMT, and mesenchymal-like cancer cells of CPKV prostate tissues. Differentially methylated sites were calculated. [2]

Animal/Disease Models: Pten conditional knockout mouse model (Pb-Cre+; PtenL/L, CP model) [2]
Doses: 75 mg/kg
Route of Administration: Po; one time/day for 4 weeks
Experimental Results: Tumor size and P- AKT staining was Dramatically diminished, the luminal structure was close to normal, and Ki67-positive cells were Dramatically diminished. Dramatically inhibits the growth of human prostate cancer.

---

Animals:** Pb-Cre⁺;Pten^(L/L) (CP) and Pb-Cre⁺;Pten^(L/L);K-ras^(G12D/W) (CPK) mice were used. All animal experiments were approved by the Ethics Committee of Peking University. [2]
**In vivo drug treatment:** BAY1082439 was dissolved in 0.1 N HCl at 75 mg/mL and orally administered at doses of 50 or 75 mg/kg/day. [2]
**PC3 xenograft study:** Approximately 3 x 10⁶ PC3 cells suspended in 50% matrigel were injected into the left flank of male nude mice. Tumors were allowed to grow to 25-50 mm² before randomization to vehicle or BAY1082439 treatment groups. [2]
**CP mouse treatment study:** CP mice were treated with 75 mg/kg of BAY1082439 daily, starting at 6 weeks of age and ending at 10 weeks. [2]
**CPK mouse treatment study:** Six-week-old CPK mice were treated with 75 mg/kg BAY1082439 daily for 4 weeks. [2]
**Castration-resistant prostate cancer (CRPC) study:** Ten-week-old CP mice were castrated and then treated with vehicle, BAY1082439 (75 mg/kg/day), or rapamycin for 4 weeks. [2]

---

Animals: Pb-Cre⁺;Pten^(L/L) (CP) and Pb-Cre⁺;Pten^(L/L);K-ras^(G12D/W) (CPK) mice were used. All animal experiments were approved by the Ethics Committee of Peking University. [2]
In vivo drug treatment: BAY1082439 was dissolved in 0.1 N HCl at 75 mg/mL and orally administered at doses of 50 or 75 mg/kg/day. [2]
PC3 xenograft study: Approximately 3 x 10⁶ PC3 cells suspended in 50% matrigel were injected into the left flank of male nude mice. Tumors were allowed to grow to 25-50 mm² before randomization to vehicle or BAY1082439 treatment groups. [2]
CP mouse treatment study: CP mice were treated with 75 mg/kg of BAY1082439 daily, starting at 6 weeks of age and ending at 10 weeks. [2]
CPK mouse treatment study: Six-week-old CPK mice were treated with 75 mg/kg BAY1082439 daily for 4 weeks. [2]
Castration-resistant prostate cancer (CRPC) study: Ten-week-old CP mice were castrated and then treated with vehicle, BAY1082439 (75 mg/kg/day), or rapamycin for 4 weeks. [2]

The pharmacokinetic profile of BAY1082439 in mice exhibits a very large volume of distribution (5.2 - 5.7 L/kg), high clearance (15 L/h/kg), and a terminal half-life (T1/2) of 0.4 hours. [2]

In the CP mouse study, BAY1082439 (75 mg/kg/day) was well tolerated over the 4-week treatment course. [2]

[1]. Abstract 2799: BAY 1082439, a highly selective and balanced PI3Kα/β inhibitor demonstrated potent activity in tumors with activated PI3Kα and loss-of-function of PTEN. Abstract nr 2799. doi:1538-7445.AM2012-2799.

[2]. Co-Targeting the Cell Intrinsic and Microenvironment Pathways of Prostate Cancer by PI3Kα/β/δ inhibitor BAY1082439. Mol Cancer Ther. 2018 Oct;17(10):2091-2099.

BAY1082439, a PI3Kα/β inhibitor, is an orally bioavailable class I phosphatidylinositol 3-kinase (PI3K) α and β subtype inhibitor with potential antitumor activity. BAY1082439 selectively inhibits PI3Kα (including PIK3CA mutants) and PI3Kβ in the PI3K/Akt/mTOR pathway, potentially leading to apoptosis and growth inhibition in PI3K- and/or PTEN-expressing tumor cells. Because this drug specifically targets class I PI3Kα and β, it may be more effective and less toxic than pan-PI3K inhibitors. PI3K/Akt/mTOR pathway dysregulation is common in solid tumors, leading to increased tumor cell growth, survival, and resistance to chemotherapy and radiotherapy. PIK3CA is one of the most frequently mutated oncogenes, encoding the p110-α catalytic subunit of class I PI3K. PTEN is a tumor suppressor protein and a negative regulator of PI3K activity, frequently mutated in various cancer cell types.

---

BAY1082439 is a new, selective PI3K inhibitor with equal potency against PI3Kα, β, and δ isoforms. [2]
BAY1082439 targets the major nodes of Pten-null prostate cancer initiation, progression, and castration-resistant growth. It is effective in inhibiting Pten-null prostate cancer growth and preventing EMT in vivo, and also blocks B cell infiltration and lymphotoxin release, which are tumor microenvironment factors that promote castration-resistant growth. [2]
The study suggests that co-targeting the cell-intrinsic and microenvironment pathways with a PI3Kα/β/δ inhibitor like BAY1082439 is a promising new approach for the treatment of prostate cancer, particularly for late-stage and castration-resistant disease. [2]

C25H30N6O5

494.552

494.227

1375469-38-7

135905473

White to off-white solid powder

1.4±0.1 g/cm3

1.683

-0.2

2

8

7

36

1010

1

O1CCN(CC1)C[C@@H](COC1C=CC2C(C=1OC)=N/C(=N\C(C1=CC=CN=C1C)=O)/N1CCNC1=2)O

QJTLLKKDFGPDPF-QGZVFWFLSA-N

InChI=1S/C25H30N6O5/c1-16-18(4-3-7-26-16)24(33)29-25-28-21-19(23-27-8-9-31(23)25)5-6-20(22(21)34-2)36-15-17(32)14-30-10-12-35-13-11-30/h3-7,17,27,32H,8-15H2,1-2H3/t17-/m1/s1

N-[8-[(2R)-2-hydroxy-3-morpholin-4-ylpropoxy]-7-methoxy-2,3-dihydro-1H-imidazo[1,2-c]quinazolin-5-ylidene]-2-methylpyridine-3-carboxamide

BAY10-82439 BAY-10-82439 BAY 10-82439

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~5 mg/mL (~10.11 mM)

Note: Listed below are some common formulations that may be used to formulate products with low water solubility (e.g. < 1 mg/mL), you may test these formulations using a minute amount of products to avoid loss of samples.

---

Injection Formulation 1: DMSO : Tween 80： Saline = 10 : 5 : 85 (i.e. 100 μL DMSO stock solution → 50 μL Tween 80 → 850 μL Saline)
*Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH ₂ O to obtain a clear solution.
Injection Formulation 2: DMSO : PEG300 ：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL DMSO → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)
Injection Formulation 3: DMSO : Corn oil = 10 : 90 (i.e. 100 μL DMSO → 900 μL Corn oil)
Example: Take the Injection Formulation 3 (DMSO : Corn oil = 10 : 90) as an example, if 1 mL of 2.5 mg/mL working solution is to be prepared, you can take 100 μL 25 mg/mL DMSO stock solution and add to 900 μL corn oil, mix well to obtain a clear or suspension solution (2.5 mg/mL, ready for use in animals).

View More

Injection Formulation 4: DMSO : 20% SBE-β-CD in saline = 10 : 90 [i.e. 100 μL DMSO → 900 μL (20% SBE-β-CD in saline)]
*Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution.
Injection Formulation 5: 2-Hydroxypropyl-β-cyclodextrin : Saline = 50 : 50 (i.e. 500 μL 2-Hydroxypropyl-β-cyclodextrin → 500 μL Saline)
Injection Formulation 6: DMSO : PEG300 : castor oil : Saline = 5 : 10 : 20 : 65 (i.e. 50 μL DMSO → 100 μLPEG300 → 200 μL castor oil → 650 μL Saline)
Injection Formulation 7: Ethanol : Cremophor : Saline = 10： 10 : 80 (i.e. 100 μL Ethanol → 100 μL Cremophor → 800 μL Saline)
Injection Formulation 8: Dissolve in Cremophor/Ethanol (50 : 50), then diluted by Saline
Injection Formulation 9: EtOH : Corn oil = 10 : 90 (i.e. 100 μL EtOH → 900 μL Corn oil)
Injection Formulation 10: EtOH : PEG300：Tween 80 : Saline = 10 : 40 : 5 : 45 (i.e. 100 μL EtOH → 400 μLPEG300 → 50 μL Tween 80 → 450 μL Saline)

---

Oral Formulation 1: Suspend in 0.5% CMC Na (carboxymethylcellulose sodium)
Oral Formulation 2: Suspend in 0.5% Carboxymethyl cellulose
Example: Take the Oral Formulation 1 (Suspend in 0.5% CMC Na) as an example, if 100 mL of 2.5 mg/mL working solution is to be prepared, you can first prepare 0.5% CMC Na solution by measuring 0.5 g CMC Na and dissolve it in 100 mL ddH2O to obtain a clear solution; then add 250 mg of the product to 100 mL 0.5% CMC Na solution, to make the suspension solution (2.5 mg/mL, ready for use in animals).

View More

Oral Formulation 3: Dissolved in PEG400
Oral Formulation 4: Suspend in 0.2% Carboxymethyl cellulose
Oral Formulation 5: Dissolve in 0.25% Tween 80 and 0.5% Carboxymethyl cellulose
Oral Formulation 6: Mixing with food powders

---

Note: Please be aware that the above formulations are for reference only. InvivoChem strongly recommends customers to read literature methods/protocols carefully before determining which formulation you should use for in vivo studies, as different compounds have different solubility properties and have to be formulated differently.

---

 (Please use freshly prepared in vivo formulations for optimal results.)