PLK1-IN-10 (Compound 4Bb) is an orally available PLK1 PBD (polo-box domain) inhibitor. PLK1-IN-10 blocks the interaction between PLK1 and cell division regulatory protein 1 (PRC1) and downregulates protein expression of the CDK1-Cyclin B1 complex. PLK1-IN-10 reacts with glutathione (GSH) to increase cellular oxidative stress and ultimately lead to cell death.

Physicochemical Properties

Molecular Formula	C23H22FN3O4S
Molecular Weight	455.50
CAS #	2991469-21-5
Appearance	Typically exists as solid at room temperature
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	PLK1 PBD
ln Vitro	PLK1-IN-10 (0-6 μM; 48 h) induces cell cycle arrest in G2/M phase of A549 and A549/DDP, inhibiting cell proliferation[1]. PLK1-IN-10 (20 μM) can stabilize PLK1 protein in A549/DDP at different temperature ranges[1]. PLK1-IN-10 (5 μM; 24 h) reacts with GSH to produce a dose- and time-dependent fluorescence response, with higher fluorescence intensity in A549/DDP cells[1]. PLK1-IN-10 (0-9 μM; 48 h) increases intracellular ROS level in A549/DDP[1]. PLK1-IN-10 (10 μM; 48 h) inhibits the interaction between PLK1 and PRC1, resulting in multinuclear phenomenon[1]. The anticancer activity of PLK1-IN-10 against NCI-H1975 cells is IC50=7.83 μM[1].
ln Vivo	PLK1-IN-10 (30, 50 mg/kg; ip; once every two days for 32 days) significantly inhibited tumor growth in A549/DDP-resistant xenograft mice, and the 50 mg/kg group even caused tumor regression [1 ]. PLK1-IN-10 (30 mg/kg; po; once every two days for 20 days) effectively inhibits tumor growth in NCI–H1975-resistant xenograft mice [1].
Cell Assay	Western Blot Analysis[1] Cell Types: A549, A549/DDP Concentration: 0, 1.5, 3, 6 μM Incubation Duration: 48 h Experimental Results: Downregulated the expression of PLK1, CDK1, Cyclin B1, as well as significantly downregulated the expression of the CDK1-Cyclin B1 complex and Cdc25 protein. Cell Cycle Analysis[1] Cell Types: A549, A549/DDP Concentration: 0, 1.5, 3, 6 μM Incubation Duration: 48 h Experimental Results: Significantly increased the number of A549 and A549/DDP cells in the G2/M phase, inducing mitotic catastrophe.
Animal Protocol	Animal/Disease Models:A549/DDP drug-resistant xenograft mice[1] Doses: 30, 50 mg/kg Route of Administration: i.p.; once every two days for 32 days Experimental Results: TGI reached 42% for the 30 mg/kg group and 62% for the 50 mg/kg group. Extended the median survival time from 38 days in the control group to 53 days in the 30 mg/kg group and 62 days in the 50 mg/kg group. Had no significant impact on the body weight and major organs of the mice, except for a slight difference in heart index observed in the 30 mg/kg group. Significantly reduced the number of Ki-67 positive cells in the tumor tissue. Showed no significant differences in H&E staining of major organs, further confirming its good biosafety.
References	[1]. Identification of naphthalimide-derivatives as novel PBD-targeted polo-like kinase 1 inhibitors with efficacy in drug-resistant lung cancer cells. Eur J Med Chem. 2024 May 5;271:116416.

Solubility Data

Solubility (In Vitro)

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

Solubility (In Vivo)

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 Formulations (e.g. IP/IV/IM/SC) 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). 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 Formulations 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). 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.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	2.1954 mL	10.9769 mL	21.9539 mL
	5 mM	0.4391 mL	2.1954 mL	4.3908 mL
	10 mM	0.2195 mL	1.0977 mL	2.1954 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.