(174) Assay Card

General Information
Summary CyO2, CyO13, kalata B1, and varv peptide A exhibited dose-dependent cytotoxicity in MTT assays with IC50 values of 2.15-7.93 uM against human brain astrocytoma cells (U-87 MG) and human bone marrow derived neuroblastoma cells (SH-SY5Y). CyO2 and varv peptide A also sensitized SH-SY5Y and U-87 MG cells to temozolomide (TMZ) which is the only effective chemotherapeutic drug used to treat glioblastoma multiforme (GBM).
Condition Refer method section in Gerlach et al., (2022).
Result (i) IC50 Best Fit for CyO2, CyO13, kalata B1, varv peptide A and TMZ against SH-SY5Y cells were 2.15 uM, 2.15 uM, 5.56 uM, 2.88 uM and 393.00 uM, respectively. (ii) IC50 Best Fit for CyO2, CyO13, kalata B1, varv peptide A and temozolomide (TMZ) against U-87 MG cells were 4.50 uM, 2.57 uM, 7.93 uM, 2.91 uM and 2898.00 uM, respectively. (iii) Co-incubation of CyO2 (0.27 uM, 8-fold less than the IC Best Fit value for CyO2 alone in SH-SY5Y cells) and TMZ (216.20 uM, 1.8 fold-less than the IC Best Fit value for TMZ alone in SH-SY5Y cells) with SH-SY5Y cells caused 50% cell death. (iv) Co-incubation of CyO2 (4.50 uM) and TMZ (352.00 uM or 1408.00 uM) with U-87 MG cells increased cell death by approximately 20%. (v) Co-incubation of varv peptide A (4.20 uM) and TMZ (1408.00 uM, 2 fold-less than the IC Best Fit value for TMZ alone in U-87 MG cells) with U-87 MG cells resulted in a significant increase in U-87 MG cell death.
AssayType Cancer Cell Toxicity

References
Gerlach,S.L., Dunlop,R.A., Metcalf,J.S., Banack,S.A., and Cox,P.A. (2022) Cyclotides Chemosensitize Glioblastoma Cells to Temozolomide. J Nat Prod 85:34-46

Cross-references
Proteins Assayed cycloviolacin O2
cycloviolacin O13
kalata B1
kalata S