Growth responses depend on the model. At 10 µM for two weeks, SB-431542 increased anchorage-independent colony formation in A549 cells, reduced it in HT29 cells and had no reported effect in VMRC-LCD cells. These divergent responses limit a general anticancer interpretation. [1]
In human breast adipose-derived stromal cells, 10 µM SB431542 reduced TGFβ1-induced SMA staining after 48 hours. The paper identifies the reagent as Adooq A10826A; this is evidence of historical use in that assay. [2]
Inhibition of TGF-β1-induced Smad signaling
Cell-based study · 293T, FET and A549 cultured human cells [1]
SB-431542 reduced TGF-β1-induced Smad2 phosphorylation and association of Smad2/3 with Smad4. This is cellular pathway evidence, not a purified kinase IC50.
Literature-Reported Treatment Conditions
- Treatment concentration
- 2 and 10 µM
- Exposure duration
- 1 hour
- Method
- Co-treatment with TGF-β1 followed by immunoprecipitation and immunoblotting
- Co-treatment
- TGF-β1, 12.5 ng/ml
- Reported limits
- Vehicle and assay-specific reagent batch are not specified in the selected experiment.
Methods and source locations
Compound reported in the paper: SB-431542; Compound label in the paper: SB-431542
Evidence concerns the named SB-431542 reagent; no salt conversion, stereoisomer substitution or validation of a current Adooq lot is inferred.
Figure 1A; Results: SB-431542 Prevents TGF-β-Induced Complex Formation between Smad2/3 and Smad4, and Blocks Nuclear Translocation of Smad2 and Smad3; Methods: Immunoprecipitation and Western Blot Analyses
TGF-β1-induced Smad2 phosphorylation and Smad2/3–Smad4 complex formation: Anti-Smad2/3 immunoprecipitation with anti-Smad4 detection; phospho-Smad2 and total Smad/β-actin immunoblots — Figure 1A image and caption; corresponding Results
Opposing anchorage-independent growth responses
Cell-based study · A549 and VMRC-LCD human lung cancer cells; HT29 human colon cancer cells [1]
SB-431542 increased A549 colony formation, reduced HT29 colony formation and had no reported effect in TGF-β-unresponsive VMRC-LCD cells. Thus, growth inhibition is not a general response across these cancer models.
Literature-Reported Treatment Conditions
- Treatment concentration
- 10 µM
- Exposure duration
- 2 weeks; added every fourth day
- Method
- Soft agarose colony formation assay
- Co-treatment
- No exogenous TGF-β treatment specified for the soft agar comparison
- Reported limits
- Vehicle not specified; do not borrow ligand treatment from the distinct six-day monolayer assay.
Methods and source locations
Compound reported in the paper: SB-431542; Compound label in the paper: SB-431542
Evidence concerns the named SB-431542 reagent; no salt conversion, stereoisomer substitution or validation of a current Adooq lot is inferred.
Figure 8A,C,E,G; Methods: Soft Agarose Assay; Results: Differential Effects of SB-431542 on Anchorage-Independent Growth of Human Cancer Cell Lines
Colony number and appearance in soft agarose: Automated colony counting after soft agar culture; untreated controls for each cell line — Figure 8A,C,E,G image and caption; soft agar Results paragraph
Suppression of TGFβ1-induced stromal-cell SMA expression
Cell-based study · Immortalized human breast adipose-derived stromal cells cultured on type I collagen [2]
SB431542 reduced the TGFβ1-induced SMA signal in breast stromal cells. The experiment is a cultured human-cell assay and does not demonstrate a drug effect in the human tissue donors or mice.
Literature-Reported Treatment Conditions
- Treatment concentration
- 10 µM
- Exposure duration
- 48 hours
- Method
- Culture on type I collagen with recombinant TGFβ1 and SB431542
- Vehicle
- DMSO control
- Co-treatment
- Recombinant human TGFβ1, 5 µg/mL as printed in Methods 2.7
- Reported limits
- No reagent purity/lot validation reported. The unusually high printed TGFβ1 concentration is retained without correction.
Methods and source locations
Compound reported in the paper: SB-431542; Compound label in the paper: SB431542
Evidence concerns the named SB-431542 reagent; no salt conversion, stereoisomer substitution or validation of a current Adooq lot is inferred.
Figure 3C; Methods 2.7 ECM isolation and culture of breast ASCs; Results 3.3 TGFβ1 complexes with decorin in ECM of breast tissue
SMA immunofluorescence normalized to DAPI area: Immunofluorescence; one-way ANOVA with Tukey multiple comparison posttest as specified in Figure 3C caption — Figure 3C image/caption; Results 3.3
