Catalog No.S2930 Synonyms: NSC 303580, PFTμ, 2-Phenylethynesulfonamide

For research use only.

Pifithrin-μ (NSC 303580, PFTμ, 2-Phenylethynesulfonamide) is a specific p53 inhibitor by reducing its affinity to Bcl-xL and Bcl-2, and also inhibits HSP70 function and autophagy.

Pifithrin-μ Chemical Structure

CAS No. 64984-31-2

Selleck's Pifithrin-μ has been cited by 15 publications

Purity & Quality Control

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Biological Activity

Description Pifithrin-μ (NSC 303580, PFTμ, 2-Phenylethynesulfonamide) is a specific p53 inhibitor by reducing its affinity to Bcl-xL and Bcl-2, and also inhibits HSP70 function and autophagy.
p53 [1]
In vitro

Pifithrin-μ interferes with p53 binding to mitochondria and inhibits rapid p53-dependent apoptosis of primary cell cultures of mouse thymocytes in response to gamma radiation. [1] Pifithrin-μ, as an inhibitor of inducible HSP70, significantly inhibited cell viability with IC50 values ranging from 2.5 to 12.7 μM in acute myeloid leukemia (AML) and acute lymphoblastic leukemia (ALL) cell lines, as well as in primary AML blasts. Pifithrin-μ is also highly active in primary AML blasts with a median IC50 of 8.9 μ M(range 5.7-37.2  μ M) and induces apoptosis and cell cycle arrest in a dose-dependent fashion. In addition, Pifithrin-μ also increases the active form of caspase-3 and reduces AKT and ERK1/2 in NALM-6 cells. [2] Pifithrin-μ increases Annexin V(+) cells in both caspase-dependent and -independent manners and promotes TRAIL-induced apoptosis and arrested cancer cell growth. [3]

Cell Data
Cell Lines Assay Type Concentration Incubation Time Formulation Activity Description PMID
Saos-2 cells M2LnNmZ2dmO2aX;uJIF{e2G7 MVyxNEDPxE1? M3n3cVQ5KGh? MnzHRolv\GmwZzDh[oZqdmm2eTD0c{BxPTNidILhcpNn\WO2ZXSgbY4hcHWvYX6gV4Fwey1{IHPlcIx{KGijcnLvdolv\yCyTG[tOVMh[XO|ZYPz[YQh[XNicnXkeYN1cW:wIH;mJJA2OyCycn;0[YlvKGmwIH3peI9kcG:wZILpZUBifCBzMDD1UUBi\nSncjC0PEBpenN? M{nBblE3QDZ{MUSx
human T293 cells M4\nRWZ2dmO2aX;uJIF{e2G7 MlH2NVUh|ryP MnqxOFghcA>? MXXCbY5lcW6pIHHm[olvcXS7IITvJJA2OyC2cnHud4Zm[3SnZDDpckBpfW2jbjDUNlk{KGOnbHzzJIF{e2W|c3XkJIF{KHKnZIXjeIlwdiCrbjDwOVMh[m:3bnStRoNtNTJiYYSgNVUhfU1iYX\0[ZIhPDhiaILz Ml\GNVY5PjJzNEG=
WI38 cells MX3GeY5kfGmxbjDhd5NigQ>? MmDRNVAh|ryP NFK2T5IzPCCq NI\kUpJKdmirYnn0bY9vKG:oIIC1N{1u\WSrYYTl[EBieG:ydH;zbZMhcW5iaIXtZY4hX0l|ODDj[YxteyCjc4Pld5Nm\CCjczDj[YxtKHO3co\peoFtKGG2IEGwJJVOKGGodHXyJFI1KGi{czDifUBu\XSqeXzlcoUh[my3ZTDhd5NigQ>? NYKyNXlHOTZ6NkKxOFE>
Methods Test Index PMID
Western blot p-LIMK / RhoA / p-4EBP1 ; c-Myc / Cyclin D1 / p21(WAF1/Cip) 20386595 24244355
Immunofluorescence p53 26958937
Growth inhibition assay Cell viability 24244355
In vivo Pifithrin-μ (40 mg/kg, ip) produces protective effect from p53-dependent apoptosis in C57B1/6J mice of 8 or 9 Gy of total body gamma radiation. [1] In a xenograft mouse model, Pifithrin-μ significantly enhances the inhibition of TRAIL on MiaPaca-2 tumor growth. [3]

Protocol (from reference)

Cell Research:


  • Cell lines: Primary thymocytes
  • Concentrations: 0-10 μM
  • Incubation Time: 24 hours
  • Method:

    The number of attached cells is estimated by staining with 0.5% methylene blue and measuring optical density using a Multiscan Ascent microplate reader. Cell viability is determined in suspension of short-term culture of primary thymocytes by staining them with 0.1% trypan blue2 or by analysis of annexin- or propidium iodide (PI)-positive cells by FACScan.

Animal Research:


  • Animal Models: C57B1/6J mice.
  • Dosages: ~40 mg/kg
  • Administration: i.p.

Solubility (25°C)

In vitro

In vivo

Add solvents to the product individually and in order
(Data is from Selleck tests instead of citations):
2% DMSO+30% PEG 300+ddH2O
For best results, use promptly after mixing.


Chemical Information

Molecular Weight 181.21


CAS No. 64984-31-2
Storage 3 years -20°C powder
2 years -80°C in solvent
Smiles C1=CC=C(C=C1)C#CS(=O)(=O)N

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Method for preparing in vivo formulation: Take μL DMSO master liquid, next add μL Corn oil, mix and clarify.

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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.

Handling Instructions

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