Cat. No.: HY-16200

Ethynylcytidine

(Synonyms: ECyD; TAS-106; 3'-C-Ethynylcytidine)

2 Cited Publications

Customer Review

Based on 2 publication(s) in Google Scholar

Ethynylcytidine (ECyD), a nucleoside analog and a potent inhibitor of RNA synthesis, inhibits RNA polymerases I, II and II. Ethynylcytidine has robust antitumor activity in a wide range of models of cancer. Ethynylcytidine is a click chemistry reagent, it contains an Alkyne group and can undergo copper-catalyzed azide-alkyne cycloaddition (CuAAc) with molecules containing Azide groups.

For research use only. We do not sell to patients.

Purity: 99.86%
CAS No.: 180300-43-0
Formula: C₁₁H₁₃N₃O₅
Molecular Weight:267.24

Storage:

Powder -20°C, 3 years , 4°C, 2 years ; In solvent -80°C, 2 years , -20°C, 1 year

Ethynylcytidine Chemical Structure

CAS No.: 180300-43-0

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Biological Activity
- Description
- IC₅₀ & Target
- Cellular Effect
- In Vitro
- In Vivo
- Clinical Trial
Chemical Information
Publications (2)
Solvent & Solubility
- In Vitro
- In Vivo
Protocol
Purity & Documentation
References
Help & FAQs
Classifications
Bioz

Biological Activity

Description

Ethynylcytidine (ECyD), a nucleoside analog and a potent inhibitor of RNA synthesis, inhibits RNA polymerases I, II and II. Ethynylcytidine has robust antitumor activity in a wide range of models of cancer^[1]^[2]^[3]. Ethynylcytidine is a click chemistry reagent, it contains an Alkyne group and can undergo copper-catalyzed azide-alkyne cycloaddition (CuAAc) with molecules containing Azide groups.

IC₅₀ & Target

RNA Polymerase

All DNA/RNA Synthesis Isoforms :

Cellular Effect

Cell Line	Type	Value	Description	References
BHK-21	CC₅₀	>100 μM Compound: NM 176	Cytotoxicity against hamster BHK21 cells assessed as reduction in cell viability after 48 to 96 hrs by MTT assay Cytotoxicity against hamster BHK21 cells assessed as reduction in cell viability after 48 to 96 hrs by MTT assay	[PMID: 19482481]
BHK-21	EC₅₀	>100 μM Compound: NM 176	Antiviral activity against Reovirus-1 infected in BHK-21 cells assessed as inhibition of virus-induced cytopathicity after 3 to 4 days by MTT assay Antiviral activity against Reovirus-1 infected in BHK-21 cells assessed as inhibition of virus-induced cytopathicity after 3 to 4 days by MTT assay	[PMID: 19482481]
BHK-21	EC₅₀	>100 μM Compound: NM 176	Antiviral activity against Yellow fever virus infected in BHK-21 cells assessed as inhibition of virus-induced cytopathicity after 3 to 4 days by MTT assay Antiviral activity against Yellow fever virus infected in BHK-21 cells assessed as inhibition of virus-induced cytopathicity after 3 to 4 days by MTT assay	[PMID: 19482481]
BHK-21	CC₅₀	>100 μM Compound: NM 176	Cytotoxicity against mock-infected BHK21 cells after 48 to 96 hrs by MTT assay Cytotoxicity against mock-infected BHK21 cells after 48 to 96 hrs by MTT assay	[PMID: 25082514]
BHK-21	EC₅₀	>100 μM Compound: NM 176	Antiviral activity against Reovirus type-1 infected in BHK21 cells assessed as inhibition of virus-induced cytopathogenicity after 3 to 4 days by MTT assay Antiviral activity against Reovirus type-1 infected in BHK21 cells assessed as inhibition of virus-induced cytopathogenicity after 3 to 4 days by MTT assay	[PMID: 25082514]
BHK-21	EC₅₀	>100 μM Compound: NM 176	Antiviral activity against Yellow fever virus infected in BHK21 cells assessed as inhibition of virus-induced cytopathogenicity after 3 to 4 days by MTT assay Antiviral activity against Yellow fever virus infected in BHK21 cells assessed as inhibition of virus-induced cytopathogenicity after 3 to 4 days by MTT assay	[PMID: 25082514]
MT4	CC₅₀	≥100 μM Compound: NM 176	Cytotoxicity against human MT4 cells after 96 hrs by MTT assay Cytotoxicity against human MT4 cells after 96 hrs by MTT assay	[PMID: 19482481]
MT4	CC₅₀	>100 μM Compound: NM 176	Cytotoxicity against mock-infected human MT4 cells after 96 hrs by MTT assay Cytotoxicity against mock-infected human MT4 cells after 96 hrs by MTT assay	[PMID: 25082514]
Vero	CC₅₀	>100 μM Compound: NM 176	Cytotoxicity against african green monkey Vero 76 cells by crystal violet staining Cytotoxicity against african green monkey Vero 76 cells by crystal violet staining	[PMID: 19482481]
Vero	EC₅₀	>100 μM Compound: NM 176	Antiviral activity against HSV1 infected in african green monkey Vero 76 cells assessed as reduction in plaque number after 3 days by plaque reduction assay Antiviral activity against HSV1 infected in african green monkey Vero 76 cells assessed as reduction in plaque number after 3 days by plaque reduction assay	[PMID: 25082514]
Vero	EC₅₀	>100 μM Compound: NM 176	Antiviral activity against Respiratory syncytial virus infected in african green monkey Vero 76 cells assessed as reduction in plaque number after 5 days by plaque reduction assay Antiviral activity against Respiratory syncytial virus infected in african green monkey Vero 76 cells assessed as reduction in plaque number after 5 days by plaque reduction assay	[PMID: 25082514]
Vero	EC₅₀	>100 μM Compound: NM 176	Antiviral activity against Vaccinia Virus infected in african green monkey Vero 76 cells assessed as reduction in plaque number after 3 days by plaque reduction assay Antiviral activity against Vaccinia Virus infected in african green monkey Vero 76 cells assessed as reduction in plaque number after 3 days by plaque reduction assay	[PMID: 25082514]
Vero	EC₅₀	>100 μM Compound: NM 176	Antiviral activity against Vesicular stomatitis virus infected in african green monkey Vero 76 cells assessed as reduction in plaque number after 2 days by plaque reduction assay Antiviral activity against Vesicular stomatitis virus infected in african green monkey Vero 76 cells assessed as reduction in plaque number after 2 days by plaque reduction assay	[PMID: 25082514]
Vero	EC₅₀	25 μM Compound: NM 176	Antiviral activity against Poliovirus type 1 Sabin strain infected in african green monkey Vero 76 cells assessed as reduction in plaque number after 2 days by plaque reduction assay Antiviral activity against Poliovirus type 1 Sabin strain infected in african green monkey Vero 76 cells assessed as reduction in plaque number after 2 days by plaque reduction assay	[PMID: 25082514]
Vero	EC₅₀	30 μM Compound: NM 176	Antiviral activity against Coxsackievirus B5 infected in african green monkey Vero 76 cells assessed as reduction in plaque number after 3 days by plaque reduction assay Antiviral activity against Coxsackievirus B5 infected in african green monkey Vero 76 cells assessed as reduction in plaque number after 3 days by plaque reduction assay	[PMID: 25082514]
Vero 76	EC₅₀	>100 μM Compound: NM 176	Antiviral activity against HSV1 infected in Vero-76 cells after 3 days by plaque reduction assay Antiviral activity against HSV1 infected in Vero-76 cells after 3 days by plaque reduction assay	[PMID: 19482481]
Vero 76	EC₅₀	>100 μM Compound: NM 176	Antiviral activity against Respiratory syncytial virus A2 infected in Vero-76 cells after 5 days by plaque reduction assay Antiviral activity against Respiratory syncytial virus A2 infected in Vero-76 cells after 5 days by plaque reduction assay	[PMID: 19482481]
Vero 76	EC₅₀	24 μM Compound: NM 176	Antiviral activity against Coxsackie virus type B2 virus infected in african green monkey Vero-76 cells after 3 days by plaque reduction assay Antiviral activity against Coxsackie virus type B2 virus infected in african green monkey Vero-76 cells after 3 days by plaque reduction assay	[PMID: 19482481]
Vero 76	CC₅₀	>100 μM Compound: NM 176	Cytotoxicity against mock-infected african green monkey Vero 76 cells after 48 to 96 hrs by MTT assay Cytotoxicity against mock-infected african green monkey Vero 76 cells after 48 to 96 hrs by MTT assay	[PMID: 25082514]

In Vitro

The IC₅₀ values of Ethynylcytidine in the five human tumors with 4, 24 and 72 h exposure range from 0.114 to 1.032 μM, 0.015 to 0.067 μM, and 0.008 to 0.058 μM, respectively. These results suggest that the cytotoxicity of Ethynylcytidine tends to become stronger as the exposure time becomes longer. The differences in IC₅₀ values between the 24 and 72 h exposure times are not large, and Ethynylcytidine appeares to show sufficiently potent cytotoxicity at the 24 h exposure time in all 5 human tumors. Even at the 4 h exposure time, Ethynylcytidine clearly shows potent cytotoxicity with IC₅₀ values at submicromolar concentrations in 4 of the 5 human tumors^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

In Vivo

In both OCUM-2MD3 and LX-1 xenografts, tumor regression is noted and a very potent antitumor effect with an tumor growth inhibition rate (IR) on day 15 of approximately 90% or even higher is observed at the minimum toxic doses of Ethynylcytidine (TAS-106) on all three administration schedules. In particular, administration of Ethynylcytidine at 6 mg/kg once weekly exhibits a marked tumor shrinking effect with an IR of 98% against the LX-1 tumor. While Ethynylcytidine treatment on an either 3 or 5 times weekly schedule has a potent antitumor effect with an IR of approximately 85%, the IR of Ethynylcytidine once weekly is less than 60% and its antitumor effect is rather weak^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

Clinical Trial

NCT Number	Sponsor	Condition	Start Date	Phase A549
NCT01329991	Plexxikon\|		2011-05	PHASE1

Chemical Information

CAS No. 180300-43-0
Appearance Solid
Molecular Weight 267.24
Formula C₁₁H₁₃N₃O₅
Color White to yellow
SMILES

OC[C@@H]1[C@](O)(C#C)[C@@H](O)[C@H](N2C(N=C(N)C=C2)=O)O1
Synonyms

ECyD; TAS-106; 3'-C-Ethynylcytidine
Shipping

Room temperature in continental US; may vary elsewhere.

Storage

Powder	-20°C	3 years
	4°C	2 years
In solvent	-80°C	2 years
	-20°C	1 year

Publications (2)

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Journal Impact Factor

Cell

RNA Pol II inhibition activates cell death independently from the loss of transcription. [Abstract]

2025 Oct 30;188(22):6301-6316.e29. PMID: 40818455
bioRxiv

Pol II degradation activates cell death independently from the loss of transcription. [Abstract]

2024 Dec 10:2024.12.09.627542. PMID: 39713309

Solvent & Solubility

In Vitro:

DMSO : 250 mg/mL (935.49 mM; Need ultrasonic; Hygroscopic DMSO has a significant impact on the solubility of product, please use newly opened DMSO)

View the Complete Stock Solution Preparation Table

Preparing Stock Solutions

View the Complete Stock Solution Preparation Table

Concentration Solvent Mass

1 mg

5 mg

10 mg

Concentration

Solvent

Mass

1 mM

3.7420 mL

18.7098 mL

37.4195 mL

5 mM

0.7484 mL

3.7420 mL

7.4839 mL

10 mM

0.3742 mL

1.8710 mL

3.7420 mL

Please refer to the solubility information to select the appropriate solvent. Once prepared, please aliquot and store the solution to prevent product inactivation from repeated freeze-thaw cycles.

Storage method and period of stock solution: -80°C, 2 years; -20°C, 1 year. When stored at -80°C, please use it within 2 years. When stored at -20°C, please use it within 1 year.

Molarity Calculator

Mass (g) = Concentration (mol/L) × Volume (L) × Molecular Weight (g/mol)

Mass Mass

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Molecular Weight Molecular Weight

Dilution Calculator

Concentration _(start) × Volume _(start) = Concentration _(final) × Volume _(final)

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In Vivo:

Select the appropriate dissolution method based on your experimental animal and administration route.

Stock Solution Working Solution

For the following dissolution methods, please ensure to first prepare a clear stock solution using an In Vitro approach and then sequentially add co-solvents:
To ensure reliable experimental results, the clarified stock solution can be appropriately stored based on storage conditions. As for the working solution for In Vivo experiments, it is recommended to prepare freshly and use it on the same day.
The percentages shown for the solvents indicate their volumetric ratio in the final prepared solution. If precipitation or phase separation occurs during preparation, heat and/or sonication can be used to aid dissolution.

Protocol 1

Add each solvent one by one: 10% DMSO 40% PEG300 5% Tween-80 45% Saline

Solubility: ≥ 2.08 mg/mL (7.78 mM); Clear solution

This protocol yields a clear solution of ≥ 2.08 mg/mL (saturation unknown).

Taking 1 mL working solution as an example, add 100 μL DMSO stock solution (20.8 mg/mL) to 400 μL PEG300, and mix evenly; then add 50 μL Tween-80 and mix evenly; then add 450 μL Saline to adjust the volume to 1 mL.

Protocol 2

Add each solvent one by one: 10% DMSO 90% (20% SBE-β-CD in Saline)

Solubility: ≥ 2.08 mg/mL (7.78 mM); Clear solution

This protocol yields a clear solution of ≥ 2.08 mg/mL (saturation unknown).

Taking 1 mL working solution as an example, add 100 μL DMSO stock solution (20.8 mg/mL) to 900 μL 20% SBE-β-CD in Saline, and mix evenly.

Protocol 3

Add each solvent one by one: 10% DMSO 90% Corn Oil

Solubility: ≥ 2.08 mg/mL (7.78 mM); Clear solution

This protocol yields a clear solution of ≥ 2.08 mg/mL (saturation unknown). If the continuous dosing period exceeds half a month, please choose this protocol carefully.

Taking 1 mL working solution as an example, add 100 μL DMSO stock solution (20.8 mg/mL) to 900 μL Corn oil, and mix evenly.

In Vivo Dissolution Calculator

Please enter the basic information of animal experiments:

Dosage Dosage
mg/kg
Animal Weight (Per Animal) Animal Weight (Per Animal)
g
Dosing Volume (Per Animal) Dosing Volume (Per Animal)
μL
Number of Animals Number of Animals

Recommended: Prepare an additional quantity of animals to account for potential losses during experiments.

Recommended: Prepare an additional quantity of animals to account for potential losses during experiments.

Please enter your animal formula composition:

%
DMSO +

Recommended: Keep the proportion of DMSO in working solution below 2% if your animal is weak.
%
+
+
%
Tween-80 + +
%
Saline +

The co-solvents required include: DMSO, . All of co-solvents are available by MedChemExpress (MCE). , Tween 80. All of co-solvents are available by MedChemExpress (MCE).

Working solution concentration: 0.22 mg/mL

Protocol

Cell Assay^[1]

MIAPaCa-2 cells are maintained in Dulbecco’s modified Eagle’s medium supplemented with 10% FCS and 2.5% horse serum. Cells in the exponential growth phase are seeded onto 6-well plates (5×10⁴ cells/1.8 mL/well) on day 0. Twenty-four hours after seeding, on day 1, Ethynylcytidine (TAS-106) (6 concentrations range from 0 to 100 μM) is added to cultured cells (3 wells at each concentration) at a volume of 0.2 mL/well. After 4 and 24 h, on the 4 and 24 h Ethynylcytidine exposure schedules, the drug-containing medium is removed, and the cells are washed twice with Dulbecco’s phosphate buffered saline and subsequently cultured in drug-free medium until day 4. On the 72 h exposure schedule, after adding the Ethynylcytidine, cells are cultured continuously until day 4. On day 4, cell numbers are determined and converted to values related to the cell numbers on day 1. The concentration of Ethynylcytidine which inhibits cell growth by 50% (IC₅₀) is calculated from this relative cell growth. Two or three individual experiments are conducted on each cell line to confirm reproducibility^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

Animal Administration^[1]

Nude rats s.c. transplanted with LX-1 human lung tumors are given a single i.v. dose of [³H]Ethynylcytidine (TAS-106) (6 mg/kg, 3.7 MBq/kg). For analysis of the distribution of radioactivity and intratumoral Ethynylcytidine metabolism, serum and various tissues (tumor, skin, lung, liver, kidney, spleen, small intestine, large intestine, testis, brain, and bone marrow cells) are sampled from 3 rats at each of the following 6 time points: 0.5, 1, 2, 4, 8 and 24 h after i.v. administration. At each point in time, bone marrow cells are collected from the 3 rats and combined into a cell pellet. All samples of serum, bone marrow cell pellets, and tissues are immediately frozen on dry ice and stored at -30°C until used^[1].

MedChemExpress (MCE) has not independently confirmed the accuracy of these methods. They are for reference only.

Purity & Documentation

Select Batch:

Purity: 99.98%

Assay: 99.98%

ee.: 99.98%

Data Sheet (282 KB)
SDS (396 KB)
- English - EN (396 KB)
- Français - FR (396 KB)
- Deutsch - DE (396 KB)
- Norwegian - NO (396 KB)
- Español - ES (396 KB)
- Swedish - SV (396 KB)
- Italian - IT (396 KB)
- Korean - KR (396 KB)
- Portuguese - PT (396 KB)
COA (2659 KB)
Elemental Analysis Report (2659 KB)
HNMR (2659 KB)
CNMR (2659 KB)
RP-HPLC (2659 KB)
NP-HPLC (2659 KB)
MS (2659 KB)
LCMS (2659 KB)
IR (2659 KB)
GC (2659 KB)
OR (2659 KB)
SDS-PAGE (2659 KB)
SEC-HPLC (2659 KB)
Other Report (2659 KB)
Handling Instructions (2659 KB)

References

[1]. Shimamoto Y, et al. Antitumor activity and pharmacokinetics of TAS-106, 1-(3-C-ethynyl-beta-D-ribo-pentofuranosyl)cytosine. Jpn J Cancer Res. 2001 Mar;92(3):343-51. [Content Brief]

[2]. Abdelrahim M, et al. TAS-106: preclinical, clinical and beyond. Oncology. 2013;85(6):356-363. [Content Brief]

[3]. Hammond-Thelin LA, et al. Phase I and pharmacokinetic study of 3'-C-ethynylcytidine (TAS-106), an inhibitor of RNA polymerase I, II and III,in patients with advanced solid malignancies. Invest New Drugs. 2012;30(1):316-326. [Content Brief]

Help & FAQs

How should lyophilized recombinant proteins be reconstituted and stored?

1. Before opening the cap, centrifuge the vial at 13000 rpm for 20-30 seconds. This step will ensure that any lyophilized powder that may have adhered to the cap or walls is collected at the bottom of the vial, minimizing the risk of product loss.

Complete Stock Solution Preparation Table

Storage method and period of stock solution: -80°C, 2 years; -20°C, 1 year. When stored at -80°C, please use it within 2 years. When stored at -20°C, please use it within 1 year.

Optional Solvent	Concentration Solvent Mass	1 mg	5 mg	10 mg	25 mg
DMSO	1 mM	3.7420 mL	18.7098 mL	37.4195 mL	93.5489 mL
	5 mM	0.7484 mL	3.7420 mL	7.4839 mL	18.7098 mL
	10 mM	0.3742 mL	1.8710 mL	3.7420 mL	9.3549 mL
	15 mM	0.2495 mL	1.2473 mL	2.4946 mL	6.2366 mL
	20 mM	0.1871 mL	0.9355 mL	1.8710 mL	4.6774 mL
	25 mM	0.1497 mL	0.7484 mL	1.4968 mL	3.7420 mL
	30 mM	0.1247 mL	0.6237 mL	1.2473 mL	3.1183 mL
	40 mM	0.0935 mL	0.4677 mL	0.9355 mL	2.3387 mL
	50 mM	0.0748 mL	0.3742 mL	0.7484 mL	1.8710 mL
	60 mM	0.0624 mL	0.3118 mL	0.6237 mL	1.5591 mL
	80 mM	0.0468 mL	0.2339 mL	0.4677 mL	1.1694 mL
	100 mM	0.0374 mL	0.1871 mL	0.3742 mL	0.9355 mL

Ethynylcytidine

2 Cited Publications

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Ethynylcytidine

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Publications Citing Use of MedChemExpress (MCE) Ethynylcytidine

All DNA/RNA Synthesis Isoforms

Biological Activity

Chemical Information

Publications (2)

Solvent & Solubility

Protocol

Purity & Documentation

References

Help & FAQs

Complete Stock Solution Preparation Table

Ethynylcytidine

Cell Cycle/DNA Damage Compound Library

Anti-Cancer Compound Library

Clinical Compound Library

Anti-Aging Compound Library

Drug Repurposing Compound Library

Reprogramming Compound Library

Nucleotide Compound Library

Anti-COVID-19 Compound Library

Anti-Lung Cancer Compound Library

Anti-Blood Cancer Compound Library

Anti-Cancer Metabolism Compound Library

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Anti-Hematopathy Compound Library

Bioactive Compound Library Max

MCE Bioactive Compound Library

Drug Repurposing Compound Library Plus

Clinical Compound Library Plus

Bioactive Compound Library

High-Throughput Bioactive Compound Library

Alkyne Compound Library

Publications Citing Use of MedChemExpress (MCE) Ethynylcytidine

All DNA/RNA Synthesis Isoforms

Biological Activity

Chemical Information

Publications (2)

Solvent & Solubility

Protocol

Purity & Documentation

References

Help & FAQs

Complete Stock Solution Preparation Table

Ethynylcytidine Related Classifications

HY-16200 Related Classifications