ATM-3507 targets the C-terminal domain of the tropomyosin isoform Tpm3.1, binding to a pocket formed between two helices of the Tpm3.1 dimer.[1]

The relative expression of Tpm3.1 and other isoforms varies throughout these cell lines. Once the IC50 values for TR100 and ATM-3507 (CHLA-20: 4.99±0.45μM, CHP-134: 3.83±0.67μM, CHLA-90: 6.84±2.37μM, SK-N-BE(2): 5.00±in) were established for each neuroblastoma cell line, testing at the level of each drug alone resulted in less than 50% of neuroblastoma cells being killed by the combination of tropomyosin inhibitor and vincristine (0.42ϼM). In CHLA-20 cells, the combination of vincristine and two tropomyosin inhibitors was totally lethal. The Chou-Talalay approach revealed some degree of synergy in all four cell lines. The effects were comparable to those of paclitaxel with TR100 or ATM-3507, and they were not exclusive to vinca alkaloids [1].

---

ATM-3507 showed potent cytotoxicity against a panel of cancer cell lines, including SK-MEL-28 (melanoma) and PC3 (prostate cancer), in a 72-hour CellTiter-Glo assay. It was selected as the lead compound from a library of >200 analogues based on potency and drug-like properties. [1]
- In SK-N-SH neuroblastoma cells, ATM-3507 (5 μM) disrupted Tpm3.1-containing filament bundles in a dose-dependent manner, with parallel decreases in cell number and Tpm3.1 filaments per cell area (p < 0.0001). [1]
- In an actin depolymerization assay, Tpm3.1 (10 μM) was preincubated with 50 μM ATM-3507 or DMSO, then mixed with F-actin (3 μM). ATM-3507 significantly reduced the ability of Tpm3.1 to protect actin from depolymerization (p < 0.0001), indicating inhibition of Tpm3.1 function. [1]
- In neuroblastoma cell lines (CHLA-20, SK-N-BE(2), SK-N-SH, CHP-134), combinations of ATM-3507 with vincristine showed strong synergy by Chou-Talalay analysis (combination index < 1). ATM-3507 reduced the IC₅₀ of vincristine in a dose-dependent manner. [1]
- Synergy was also observed with paclitaxel, but only slight synergy with doxorubicin, suggesting specificity for antimicrotubule agents. [1]
- In CHLA-20 cells, combination of ATM-3507 (4 μM) with vincristine (10 nM) induced G₂–M phase arrest (p < 0.05) and increased condensed chromatin compared to single agents. [1]
- Combination treatment disrupted mitotic spindle organization, leading to poorly organized spindles. [1]
- Annexin V/PI staining showed time-dependent induction of early and late apoptosis in CHLA-20 cells treated with ATM-3507 plus vincristine. Western blot revealed cleaved PARP, indicating caspase activation. The pan-caspase inhibitor Z-VAD-FMK partially prevented combination-induced cell death. [1]

TR100 and ATM-3507 have maximum tolerated doses (MTDs) of 60 and 150 mg/kg, respectively. When compared to each treatment alone, the study discovered that applying either combination greatly slowed the growth of tumors and increased animal survival. Mice treated with ATM-3507 had a median survival of 18 days, whereas mice treated with the combination had a median survival of over 49 days. ATM-3507 intravenous infusions administered twice a week were also found to exhibit combined efficacy. The impact on body weight was marginal for each treatment or combination. Following an intravenous injection of ATM-3507 at a dose of 30 mg/kg, the drug levels in Balb/c mice (n = 3 per time point) were assessed. In the terminal elimination phase, ATM-3507 has an average half-life of 5.01 hours. In plasma, the mean AUC0-t was 14,548 ng/h/mL. ATM-3507 has a t1/2 of 5.01 hours and a Cmax of 5,758 ng/mL. ATM-3507 was found to have a steady-state plasma clearance of 33.8 mL/min/kg and a volume of distribution of 7.23 L/kg [1].

---

In athymic nude mice bearing CHLA-20 human neuroblastoma xenografts, ATM-3507 (150 mg/kg/day, i.p., daily for 17 days) combined with vincristine (0.5 mg/kg, i.v., days 4 and 11) significantly inhibited tumor growth and prolonged median survival (>49 days) compared to monotherapy (median survival: 18 days for ATM-3507 alone). [1]
- In another dosing regimen, intravenous ATM-3507 (30 mg/kg, twice weekly) combined with vincristine also showed combination efficacy. [1]
- Body weight loss was minimal in all treatment groups. [1]

Cell viability: Cells were plated in 96-well plates at 3,000–5,000 cells/well, treated with compounds for 72 h, then exposed to CellTiter-Glo reagent for 30 min. Luminescence was measured, and IC₅₀ values were calculated. [1]
- Tpm3.1 filament quantitation: SK-N-SH cells were treated with ATM-3507 (0–10 μM) for 24 h, fixed, stained with γ9d antibody (Tpm3.1/3.2), and imaged by confocal microscopy. Linear feature detection algorithm quantified filament bundles. [1]
- Actin depolymerization assay: Pyrene-labeled F-actin (3 μM) was incubated with Tpm3.1 (10 μM) with or without ATM-3507 (50 μM). Depolymerization was monitored by fluorescence (407 nm) over 60 min. [1]
- Cell cycle analysis: Cells were treated with ATM-3507 (4 μM) ± vincristine (10 nM for CHLA-20; 1.5 nM for SKNBe2) for 24 h, fixed in ethanol, stained with propidium iodide, and analyzed by flow cytometry. [1]
- Apoptosis: Annexin V/PI staining and flow cytometry were performed after 6, 20, and 30 h of treatment. Western blot for cleaved PARP was performed on cell lysates. [1]
- Immunofluorescence: Cells on coverslips were fixed in methanol or paraformaldehyde, stained with anti-α-tubulin (1:300) and DAPI, and imaged by confocal microscopy. [1]

Female athymic nude mice (4–6 weeks) were injected subcutaneously with 5 × 10⁶ CHLA-20 cells in PBS/Matrigel (2:1). [1]
- ATM-3507 was formulated at 15 mg/mL in 30% sulfobutyl-ether-β-cyclodextrin sodium salt (SBECD). Vincristine was dissolved in water at 0.125 mg/kg. [1]
- Dosing regimen 1: ATM-3507 (150 mg/kg, i.p., daily for 17 days); vincristine (0.5 mg/kg, i.v., on days 4 and 11). [1]
- Dosing regimen 2: ATM-3507 (30 mg/kg, i.v., twice weekly); vincristine as above. [1]
- Tumor volume was measured twice weekly using digital calipers (formula: a × b² × π/6). Mice were euthanized when tumors reached >2,000 mm³, weight loss >20%, or other endpoint criteria. [1]
- A truncated MTD study determined the maximum tolerated dose: 60 mg/kg for TR100 and 150 mg/kg for ATM-3507. [1]

---

Female athymic nude mice (4–6 weeks) were injected subcutaneously with 5 × 10⁶ CHLA-20 cells in PBS/Matrigel (2:1). [1]
- ATM-3507 was formulated at 15 mg/mL in 30% sulfobutyl-ether-β-cyclodextrin sodium salt (SBECD). Vincristine was dissolved in water at 0.125 mg/kg. [1]
- Dosing regimen 1: ATM-3507 (150 mg/kg, i.p., daily for 17 days); vincristine (0.5 mg/kg, i.v., on days 4 and 11). [1]
- Dosing regimen 2: ATM-3507 (30 mg/kg, i.v., twice weekly); vincristine as above. [1]
- Tumor volume was measured twice weekly using digital calipers (formula: a × b² × π/6). Mice were euthanized when tumors reached >2,000 mm³, weight loss >20%, or other endpoint criteria. [1]
- A truncated MTD study determined the maximum tolerated dose: 60 mg/kg for TR100 and 150 mg/kg for ATM-3507. [1]

In Balb/c mice (n = 3 per time point) after intravenous administration of ATM-3507 at 30 mg/kg: mean half-life (t₁/₂) = 5.01 hours (terminal elimination phase); mean AUC₀–ₜ = 14,548 ng·h/mL; Cmax = 5,758 ng/mL; plasma clearance = 33.8 mL/min/kg; volume of distribution at steady state = 7.23 L/kg. [1]

ATM-3507 was well tolerated in mouse and dog models with no impact on skeletal muscle studies, suggesting it can discriminate between tumor actin cytoskeleton and muscle sarcomere. [1]
- In xenograft studies, body weight loss was minimal in combination treatment groups. [1]
- ATM-3507 lacks the reactive α,β-unsaturated carbonyl moiety present in TR100, a functional group associated with reactive metabolite formation. [1]

[1]. Identification of Cancer-Targeted Tropomyosin Inhibitors and Their Synergy with Microtubule Drugs.Mol Cancer Ther. 2017 Aug;16(8):1555-1565.

ATM-3507 was developed as a lead antitropomyosin compound targeting the Tpm3.1 isoform, which is enriched in most cancers. It retains the indole scaffold of TR100 but has a modified nonpolar arm attached at the 5-position (vs. 3-position in TR100), allowing better contact with Tpm3.1 helices and improved selectivity. [1]
- The compound was designed using structure-based drug design targeting the C-terminal domain of Tpm3.1. Molecular modeling predicted that ATM-3507 binds to a cavity between two helices of the Tpm3.1 dimer, interacting with side chains specific to the Tpm3.1 isoform. [1]
- ATM-3507 synergizes with antimicrotubule agents (vincristine, paclitaxel) in neuroblastoma models, leading to G₂–M arrest, mitotic spindle disruption, and apoptosis. The mechanism likely involves collaboration between Tpm3.1-containing actin filaments and microtubules during mitosis. [1]
- This study supports further development of ATM-3507 in combination with antimicrotubule agents for cancer therapy. [1]

C37H46FN5O2

611.791852474213

611.363

1861449-70-8

ATM-3507 trihydrochloride;2438679-30-0

118666864

Light yellow to yellow solid powder

5.8

0

6

10

45

917

0

FC1C=CC(=CC=1)CCN1CCN(C(C2C=CC=C(C=2)OC2C=CC3=C(C=2)C(C)=C(C)N3CCCN2CCN(C)CC2)=O)CC1

FNEHSJQRIWHZKS-UHFFFAOYSA-N

InChI=1S/C37H46FN5O2/c1-28-29(2)43(16-5-15-40-20-18-39(3)19-21-40)36-13-12-34(27-35(28)36)45-33-7-4-6-31(26-33)37(44)42-24-22-41(23-25-42)17-14-30-8-10-32(38)11-9-30/h4,6-13,26-27H,5,14-25H2,1-3H3

(3-((2,3-Dimethyl-1-(3-(4-methylpiperazin-1-yl)propyl)-1H-indol-5-yl)oxy)phenyl)(4-(4-fluorophenethyl)piperazin-1-yl)methanone

ATM3507 ATM 3507 ATM-3507

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: This product requires protection from light (avoid light exposure) during transportation and storage.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

DMSO : ~33.33 mg/mL (~54.48 mM)

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 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).

View More

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 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).

View More

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.)