PROTAC AR Degrader-12 targets the androgen receptor (AR) coactivator binding site (AR-CBS). AR is a nuclear hormone receptor that plays a critical role in the development and progression of prostate cancer and breast cancer. This PROTAC degrader also effectively blocks estrogen receptor alpha (ERalpha) signaling through a dual mechanism involving ERalpha protein downregulation and suppression of its transcriptional activity. In addition, it targets estrogen receptor alpha (ERalpha) indirectly and significantly inhibits the mRNA expression of FOXA1, GREB1, SRC, and PELP1.

PROTAC AR Degrader-12 (Compound 18o) showed good inhibitory activity against MCF-7 (IC50 = 0.13 μM) and LCC2 cells (IC50 = 0.54 μM), and had broad-spectrum efficacy against clinically relevant mutants. It showed strong sub-micromolar inhibitory effects against MCF-7D538G (IC50 = 0.66 μM), MCF-7Y537S (IC50 = 0.44 μM) and MCF-7EGFR (IC50 = 0.52 μM) [1]. PROTAC AR Degrader-12 (0.01-2 μM, 24 hours) can effectively degrade AR protein in MCF-7 cells (DC50 = 0.72 μM) in a dose-dependent manner [1]. PROTAC AR Degrader-12 (1 μM, 0–24 h) showed a time-dependent effect on the degradation of AR in MCF-7 cells[1]. PROTAC AR Degrader-12 (0.01–2 μM, 24 h) led to a concentration-dependent downregulation of ERα protein expression in MCF-7 cells[1]. PROTAC AR Degrader-12 (0.01–2 μM, 12–24 h) significantly downregulated ERα protein expression in MCF-7D538G, MCF-7Y537S, MCF-7EGFR, LCC2, and T47D cells, but failed to downregulate ERβ protein expression in PC9 cells[1]. PROTAC AR Degrader-12 (1 μM, 24 h) induced a reduction in ERα through an indirect mechanism rather than directly targeting the degradation of CBS in MCF-7 cells[1]. PROTAC AR Degrader-12 (0-5 μM, 0-24 h) reduces the expression of AR protein in MCF-7 cells through posttranscriptional degradation, while the reduction of ERα is due to transcriptional repression [1]. PROTAC AR Degrader-12 showed potent antiproliferative activity in AR-overexpressing but ERα-deficient prostate cancer cells LNCaP (IC50 = 0.46 μM), but its antiproliferative activity was significantly reduced in AR-negative MDA-MB-231 cells (IC50 > 30 μM) [1]. PROTAC AR Degrader-12 can effectively stabilize AR protein at high temperature, but has a weak protective effect on ERα protein, which indicates that PROTAC AR Degrader-12 binds to AR in LCC2 cells but not to ERα [1]. PROTAC AR Degrader-12 (1 μM, 24 h) significantly inhibited the mRNA expression of FOXA1, GREB1, SRC and PELP1 in MCF-7 cells [1]. PROTAC AR Degrader-12 (1-10 μM, 48 h) induced S phase cell cycle arrest in MCF-7 and LCC2 cells [1].

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In vitro, PROTAC AR Degrader-12 (Compound 18o) shows good inhibitory activity against MCF-7 breast cancer cells with IC50 = 0.13 microM and LCC2 cells with IC50 = 0.54 microM, with broad-spectrum efficacy against clinically relevant mutants. It shows strong sub-micromolar inhibitory effects against MCF-7D538G (IC50 = 0.66 microM), MCF-7Y537S (IC50 = 0.44 microM), and MCF-7EGFR (IC50 = 0.52 microM). PROTAC AR Degrader-12 (0.01-2 microM, 24 hours) effectively degrades AR protein in MCF-7 cells in a dose-dependent manner with DC50 = 0.72 microM. The compound (1 microM, 0-24 h) shows a time-dependent effect on AR degradation. It also leads to concentration-dependent downregulation of ERalpha protein expression in MCF-7 cells, and significantly downregulates ERalpha protein expression in MCF-7D538G, MCF-7Y537S, MCF-7EGFR, LCC2, and T47D cells, but fails to downregulate ERbeta in PC9 cells. The reduction of ERalpha is due to transcriptional repression, while AR reduction occurs via posttranscriptional degradation. PROTAC AR Degrader-12 also shows potent antiproliferative activity in AR-overexpressing but ERalpha-deficient prostate cancer cells LNCaP (IC50 = 0.46 microM).

PROTAC AR Degrader-12 (Compound 18o) (5-10 μM/kg, intraperitoneal injection, every other day) significantly inhibited tumor growth in MCF-7 cells and LCC2 xenograft mice, promoted AR protein modification and ERα signaling inhibition, without causing weight loss or other toxicities [1].

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In vivo, PROTAC AR Degrader-12 has demonstrated significant antitumor activity in breast cancer xenograft models. The compound effectively degrades AR in tumor tissues and inhibits tumor growth in a dose-dependent manner. It also blocks ERalpha signaling in vivo, contributing to its anti-proliferative effects in estrogen receptor-positive breast cancers. The compound can be used for breast cancer research and has potential applications in AR-positive and ER-positive malignancies. Specific details of in vivo dosing, tumor growth inhibition percentages, and pharmacodynamic markers are not fully described in the available literature but have been reported in patent applications.

No specific enzyme/receptor binding protocols have been established for PROTAC AR Degrader-12 as it is a bifunctional PROTAC molecule rather than a conventional inhibitor. For AR binding affinity, standard radioligand binding assays using [3H]R1881 or fluorescent AR ligands and LNCaP cell lysates or purified AR ligand-binding domain can measure the AR-binding component of the PROTAC. For VHL binding, fluorescence polarization or surface plasmon resonance using recombinant VHL-elongin B-elongin C complex can assess affinity of the E3 ligase ligand component. For ternary complex formation (AR:PROTAC:VHL), AlphaScreen or TR-FRET assays using tagged AR and VHL proteins can detect formation of the ternary complex. In vitro ubiquitination assays using purified E1, E2, and E3 ligase components with AR as substrate can measure PROTAC-induced ubiquitination.

Western Blot Analysis[1]
Cell Types: MCF-7 cells
Tested Concentrations: 0.01 μM, 0.1 μM, 1 μM, 2 μM
Incubation Duration: 0 h, 3 h, 6 h, 12 h, 18 h, 24 h
Experimental Results: Effectively and in a dose-dependent manner degraded AR protein. Time-dependent effect on AR degradation. Caused a concentration-dependent downregulation of ERα protein.

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Real Time qPCR[1]
Cell Types: MCF-7 cells
Tested Concentrations: 0 μM, 1 μM, 5 μM
Incubation Duration: 0 h, 4 h, 24 h
Experimental Results: AR mRNA expression increased significantly with increasing concentration; ERα mRNA expression was downregulated. The expression of ERα target genes (TFF1, PGR) and AR target genes (PSA, TMPRSS2) was significantly suppressed after 24 hours. Significantly inhibited the mRNA expression of FOXA1, GREB1, SRC, and PELP1.

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In vitro cellular protocols for PROTAC AR Degrader-12 involve culturing AR-positive and ER-positive breast cancer cell lines such as MCF-7, T47D, LCC2, and prostate cancer cell line LNCaP in RPMI-1640 or DMEM with 10% FBS at 37degC in 5% CO2. Cells are seeded in 6-well plates (2×10⁵ cells/well) for western blot analysis or 96-well plates (5,000-10,000 cells/well) for viability assays. Cells are treated with varying concentrations of PROTAC AR Degrader-12 (0.01-2 microM) for 4-24 hours (degradation time course) or 0.01-5 microM for 24 hours (dose-response). For DC50 determination, cells are treated with 0.01-2 microM for 24 hours. AR and ERalpha protein levels are assessed by western blotting using specific antibodies, with GAPDH or beta-actin as loading control. Cell viability is assessed by MTT or CellTiter-Glo assays after 72 hours of treatment. Proliferation assays are also performed in LNCaP cells (0.01-5 microM, 72 hours). All experiments are performed in triplicate.

Animal/Disease Models: Balb/c nude mice (female, 4 weeks old) were subcutaneously injected with MCF-7 human breast cancer cells (5 × 106 cells)[1].
Doses: 5 μM/kg, 10 μM/kg
Route of Administration: I.p., once every other day
Experimental Results: At a dose of 10 μM/kg, it significantly inhibited tumor growth. Tumor volume decreased, and Ki67 proliferation marker expression was reduced. AR and ERα protein levels were downregulated in tumor tissue. No significant change in body weight or significant toxicity was observed.

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Animal/Disease Models: Balb/c nude mice (female, 4 weeks old) were subcutaneously injected with tamoxifen-resistant LCC2 human breast cancer cells (5 × 106 cells)[1].
Doses: 5 μM/kg, 10 μM/kg
Route of Administration: I.p., once every other day
Experimental Results: Tumor growth inhibition rate (TGI) reached 58% at a dose of 10 μM/kg. Ki67 expression was decreased, and AR and ERα proteins were downregulated. Body weight remained stable, with no signs of toxicity.

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For in vivo studies of PROTAC AR Degrader-12, standard animal protocols involve xenograft models in immunodeficient mice (nude mice or NSG mice, female for breast cancer models, male for prostate cancer models). Approximately 5×10⁶ MCF-7 cells (supplemented with estrogen pellets) or LNCaP cells are injected subcutaneously. When tumors reach ~150-200 mm3, mice are randomized into treatment groups (n=5-10 per group). PROTAC AR Degrader-12 is administered intraperitoneally or intravenously at doses of 10-50 mg/kg in formulation vehicles such as 10% DMSO, 40% PEG300, 5% Tween 80, 45% saline. Dosing frequency may be daily or every other day. Tumor volumes are measured every 2-3 days using digital calipers (formula: volume = length × width2 / 2). Body weights are monitored as a toxicity indicator. At study termination, tumors are excised and processed for AR and ERalpha protein analysis by western blotting and immunohistochemistry. Blood may be collected for pharmacokinetic analysis. All procedures require approval by institutional animal care committees.

No direct pharmacokinetic studies have been published for PROTAC AR Degrader-12. As a PROTAC molecule with molecular weight in the range of 800-1000 Da (typical for PROTACs), it may have moderate to poor oral bioavailability. The compound is likely administered intravenously or intraperitoneally in animal studies. Pharmacokinetic properties such as half-life, clearance, volume of distribution, and bioavailability would be determined by the specific structure of the molecule. The compound is soluble in DMSO and can be formulated for injection. No specific PK parameters are reported in the available literature.

According to safety data, PROTAC AR Degrader-12 is for research use only and not for human therapeutic applications. Standard laboratory safety precautions should be followed: wear protective gloves, safety goggles, and a lab coat. Work in a well-ventilated fume hood. Avoid inhalation, ingestion, and contact with skin and eyes. The compound should be stored as a powder at -20degC for up to 3 years or at 4degC for 2 years. In solution, store at -80degC for 6 months or -20degC for 1 month. As a PROTAC that degrades AR and ERalpha, potential hormonal effects should be considered when handling, especially by individuals who are pregnant or may become pregnant. This product is not for human therapeutic use.

[1]. Kill Two Birds with One Stone: An Efficient and Potent AR CBS-Targeted Degrader Reverses Breast Cancer Resistance via Concurrent AR Degradation and ERα Transcriptional Suppression. J Med Chem. 2025 Nov 27;68(22):24136-24167.

PROTAC AR Degrader-12 is a highly potent PROTAC targeting the androgen receptor (AR) coactivator binding site (AR-CBS). It induces AR degradation via the ubiquitin-proteasome system (UPS) pathway and inhibits tumor cell growth by affecting DNA replication and cell division. This compound not only effectively degrades AR but also potently inhibits the proliferation of MCF-7 cells and various mutant or drug-resistant breast cancer cells, including those with ESR1 mutations (D538G, Y537S) that confer resistance to endocrine therapies. PROTAC AR Degrader-12 effectively blocks estrogen receptor alpha (ERalpha) signaling through a dual mechanism involving ERalpha protein downregulation and suppression of its transcriptional activity. It significantly inhibits the mRNA expression of FOXA1, GREB1, SRC, and PELP1, which are key ERalpha co-regulators. The compound can be used for breast cancer research and has potential applications in both prostate cancer and endocrine-resistant breast cancer. No clinical trial data is available; the compound is for research use only and not approved for human therapy.

C57H76N8O10S

1065.33

Typically exists as solids at room temperature

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)

May dissolve in DMSO (in most cases), if not, try other solvents such as H2O, Ethanol, or DMF with a minute amount of products to avoid loss of samples

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.

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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).

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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)

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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).

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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

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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.

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