Catalog No.S2738

For research use only.

PAC-1 is a potent procaspase-3 activator with EC50 of 0.22 μM and the first small molecule known to directly activate procaspase-3 to caspase-3.

PAC-1 Chemical Structure

CAS No. 315183-21-2

Selleck's PAC-1 has been cited by 11 Publications

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Biological Activity

Description PAC-1 is a potent procaspase-3 activator with EC50 of 0.22 μM and the first small molecule known to directly activate procaspase-3 to caspase-3.
Features The first small molecule known to directly activate procaspase-3 to caspase-3.
Procaspase-3 [1]
0.22 μM(EC50)
In vitro

PAC-1 activates procaspase-7 in a less efficient manner with EC50 of 4.5 μM. Elevated caspase 3 level in cancer cell lines allows PAC-1 to selectively induce apoptosis in a manner proportional to procaspase-3 concentration with IC50 of 0.35 μM for NCI-H226 cells to ~3.5 μM for UACC-62 cells. PAC-1 induces apoptosis in the primary cancerous cells with IC50 values of 3 nM to 1.41 μM, more potently than in the adjacent noncancerous cells with IC50 of 5.02 μM to 9.98 μM, which is also directly related to the distinct procaspase-3 concentration. [1] PAC-1 activates procaspase-3 by chelating zinc ions, thus relieving the zinc-mediated inhibition and allowing procaspase-3 to auto-activate itself to caspase-3. [2] PAC-1 is capable to induce cell death in Bax/Bak double-knockout cells and Bcl-2 and Bcl-xL-overexpressing cells with the same efficacy as its wild-type counterpart in a delayed manner. PAC-1 induces cytochrome c release in a caspase-3 independent manner, which subsequently triggers downstream caspase-3 activation and cell death. PAC-1 can not induce cell death and caspase-3 activation in Apaf-1 knockout cells, suggesting that apoptosome formation is essential for caspase-3 activation by PAC-1-mediated cell death. [3]

Methods Test Index PMID
Western blot Ero1-Lα / Calnexin / IRE-1α / p-eIF2α / eIF2α / CHOP 24357799
Immunofluorescence Hif1α ; p-H2AX / Rad51 30287840
In vivo Administration of PAC-1 at 5 mg with low and steady releasing significantly inhibits the growth of ACHN renal cancer xenograft in mice. Oral administration of PAC-1 (50 or 100 mg/kg) significantly retards tumor growth of NCI-H226 lung cancer xenograft in a dose-dependent manner, and markedly prevents the cancer cells from infiltrating the lung tissue. The in vivo anti-tumor effect of PAC-1 is ascribed to procaspase-3 activation and subsequently apoptosis induction consistent with the activity in vitro. [1]

Protocol (from reference)

Kinase Assay:[1]
  • In vitro procaspase-3 activation:

    Procaspase-3 is expressed and purified in Escherichia coli. Various concentrations of PAC-1 are added to 90 μL of a 50 ng/mL of procaspase-3 in caspase assay buffer in a 96-well plate, The plate is incubated for 12 hours at 37 °C. A 10 μL volume of a 2 mM solution of caspase-3 peptidic substrate acetyl Asp-Glu-Val-Asp-p-nitroanilide (Ac-DEVD-pNa) in caspase assay buffer is then added to each well. The plate is read every 2 minutes at 405 nm for 2 hours in a Spectra Max Plus 384 well plate reader. The slope of the linear portion for each well is determined, and the relative increase in activation from untreated control wells is calculated.

Cell Research:[1]
  • Cell lines: U-937, HL-60, CRL-1872, ACHN, NCI-H226, Hs888Lu, Hs578Bst, MCF-10A, SK-MEL-5, BT-20, MDA-MB-231, UACC-62, SK-N-SH, B16-F10 , Hs 578t, and PC-12
  • Concentrations: Dissolved in DMSO, final concentrations ~100 μM
  • Incubation Time: 72 hours
  • Method: Cells are exposed to various concentrations of PAC-1 for 72 hours. Cell death is quantified by the addition of MTS/PMS CellTiter 96 Cell Proliferation Assay reagent. The plates are incubated at 37 °C for approximately 1 hour (until the colored product formed), and the absorbance is measured at 490 n
Animal Research:[1]
  • Animal Models: Ovariectomized female athymic BALB/c (nude, nu/nu) mice injected subcutaneously with ACHN cells, male athymic BALB/c nude mice injected subcutaneously with NCI-H226 cells, and male athymic BALB/c–/– mice injected intravenously with NCI-H226 cells
  • Dosages: ~100 mg/kg
  • Administration: Pellet implantation subcutaneously or oral gavage

Solubility (25°C)

In vitro

In vivo

Add solvents to the product individually and in order
(Data is from Selleck tests instead of citations):
30% PEG400+0.5% Tween80+5% propylene glycol
For best results, use promptly after mixing.

30 mg/mL

Chemical Information

Molecular Weight 392.49


CAS No. 315183-21-2
Storage 3 years -20°C powder
2 years -80°C in solvent

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Clinical Trial Information

NCT Number Recruitment Interventions Conditions Sponsor/Collaborators Start Date Phases
NCT04589832 Recruiting Drug: PAC-1|Drug: Entrectinib Uveal Melanoma Arkadiusz Z. Dudek MD|HealthPartners Regions Cancer Care and Frauenshuh Cancer Care Centers|Vanquish Oncology Inc.|Genentech Inc.|Midwest Melanoma Partnership|Hoosier Cancer Research Network January 11 2021 Phase 1|Phase 2
NCT03927248 Withdrawn Drug: Nivolumab Metastatic Renal Cell Carcinoma HealthPartners Institute September 2020 Phase 1|Phase 2
NCT03441412 Completed Drug: Ticagrelor 90mg|Drug: Epinephrine|Drug: Metoprolol Healthy Volunteers Vastra Gotaland Region|Gothia Forum - Center for Clinical Trial|Uppsala University February 28 2018 Phase 1
NCT03306550 Unknown status Drug: salvianolate injection|Drug: Aspirin Tablet Angina Stable Xiyuan Hospital of China Academy of Chinese Medical Sciences October 10 2017 Not Applicable

(data from, updated on 2022-01-17)

Tech Support

Answers to questions you may have can be found in the inhibitor handling instructions. Topics include how to prepare stock solutions, how to store inhibitors, and issues that need special attention for cell-based assays and animal experiments.

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