Journal: bioRxiv
Article Title: Loss of Flotillin-2 enhances trastuzumab emtansine internalization and cytotoxicity by relieving negative regulation of HER2 internalization in HER2-amplified cancers
doi: 10.64898/2026.05.15.725439
Figure Lengend Snippet: A) SKBR3 shFLOT2 or shControl were pretreated with DMSO control (black) or 500 ng/mL doxycycline (gray) for 48 hours in 1% FBS RPMI, then treated with indicated T-DM1 concentration with continued doxycycline in 1% FBS RPMI for three days prior to cell counting. The table below the graphs indicates the calculated IC50 comparing DMSO + T-DM1 to doxycycline + T-DM1. Data represents the average ±SEM of at least three independent experiments, and statistical analysis was performed by Student’s t-test. B) Same as in A, with HCC202 shFLOT2 or shControl. C) Same as in A, with HCC1954 shFLOT2 or shControl. D) ARK1 (top) or ARK2 (bottom) cells were transfected with siNeg (black) or siFLOT2 (gray) for 48 hours prior to being treated with indicated T-DM1 concentration in 10% FBS RPMI for three days prior to cell viability reading (CellTiter-Glo 2.0). Data represents the average ±SEM of at least three independent experiments, and statistical analysis was performed by Student’s t-test. E) SKBR3, HCC202, HCC1954, BT474, HCC1419, HCC2218, UACC893, ARK1, and ARK2 cells were treated with 0-1000 ng/mL T-DM1 in 1% FBS RPMI for three days prior to cell counting. Average FLOT2 expression by immunoblot (relative to HSC70 loading control) and the calculated IC50 for each cell line was plotted. Protein expression and IC50 were calculated from at least three independent experiments. Line represents linear regression. F) Same as E, with average HER2 expression (relative to HSC70 loading control). G) Overall survival of patients in Caris dataset from T-DXd to last contact with high FLOT2 (orange; 16.22 months) vs low FLOT2 (blue; 18.26 months), p=0.041. H) Overall survival of patients in Caris dataset from T-DM1 to last contact with high FLOT2 (orange; 37.967 months) vs low FLOT2 (blue; 41.29 months), p=0.131.
Article Snippet: The Caris deidentified sequencing data are owned by Caris Life Sciences and cannot be publicly shared due to the data usage agreement in place.
Techniques: Control, Concentration Assay, Cell Counting, Transfection, Expressing, Western Blot
