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PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
To knock down STUB1, we transfected cells with siRNA duplex oligos in OPTI-MEM (#2185849, Gibco) overnight.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Expression plasmids encoding Myc-STUB1 (#90977–1), Flag-GPX4 (#68273–1), HA-ubiquitin (Ub, #61618–1), GPX4-K107R (#68273–2), GPX4-K126R (#68273–3), GPX4-K162R (#68273–4), GPX4-K167R (#68273–5), and GPX4-K191R (#68273–6) (GPX4 mutants with lys107, lys126, lys162, lys167 and lys191 changed into arginine) were purchased from Genechem (Genechem, Shanghai, China).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
All plasmids were transfected with Lipofectamine™ 3000 Transfection Reagent (#L3000015, ThermoFisher, Shanghai, China) according to the protocol.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
STUB1 and GPX4 expression lentiviruses were purchased from Genechem (Genechem, Shanghai, China).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Transfection was performed according to the manufacturer’s protocols.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The transfected cells were screened by puromycin (2 mg/mL) (ST551, Beyotime, Beijing, China) to establish a stably expressing cell line (Fig. S1).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Cells were resuspended in a buffer containing 4% paraformaldehyde and 1% glutaraldehyde and subsequently dehydrated through graded ethanol and propylene oxide, which was then embedded in Epon 812 and sliced into 60-nm ultrathin sections.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The mitochondrial area and structure were finally assessed by transmission electron microscopy (H-7650, Hitachinaka, Japan).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
ROS or lipid ROS levels were measured in the GIST-T1 and GIST-882 cells treated with IM (50 nM for T1 and 200 nM for 882) or Ferrostatin-1 (1 μM) for 12 h, by adding 10 µM 2ʹ,7ʹ-dichlorofluorescein diacetate (DCFH-DA) (ab113851, ROS Detection Assay Kit, Abcam) or 10 µM C11-BODIPY (#D3861, Thermo Fisher Scientific) for 30 min at 37 °C, followed by trypsinization, washing and resuspension in phosphate buffered saline (PBS).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
ROS and lipid ROS levels were then measured by confocal microscopy (Carl Zeiss, Jena, Germany) or flow cytometry.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Flow cytometry analysis was performed using the SONY SH800 Cell Sorter with the FITC filter for oxidized C11-BODIPY (emission: 510 nm) and the PE-TexasRed filter for reduced C11-BODIPY (emission: 590 nm).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
At least 10,000 cells were collected for each condition, and this experiment was independently repeated three times.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Data analysis was carried out using the FlowJo software (version 9.4.10, Tree Star).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The results are expressed as the ratio of oxidized to reduced C11-BODIPY.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Change of intracellular Fe in GIST cells was detected with the novel fluorescent probe FerroOrange (F374, Dojindo) according to the manufacturer’s protocol.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
GIST-T1 and GIST-882 cells treated with IM were incubated with 1 µM FerroOrange at 37 °C for 30 min.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The fluorescence was then measured by flow cytometry.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
GSH and GSSG levels were determined using the GSH and GSSG Assay Kit (Beyotime, S0053) following the manufacturer’s instructions.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
To prepare the samples, GIST-T1 and GIST-882 cells were mixed with protein removal reagent M in a three-fold volume and thoroughly vortexed.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Subsequently, two freeze-thaw cycles (5 s freeze, 1 min thaw) were performed alternating between liquid nitrogen and a 37 °C water bath.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
After centrifugation at 10,000 g for 10 min at 4 °C, the resulting supernatant was collected as the sample solution.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
All samples were normalized based on their protein content.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Then, the 0.2 ml sample solution was mixed with 1 mM GSH solution of the same volume and incubated at 37 °C for 5 min; after addition of 0.1 ml reagent 1 and incubation at 37 °C for another 5 min, 2 ml reagent 2 was added.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The mixture was then centrifuged at 10,000 g for 10 min.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The supernatant (1 ml) was extracted and mixed with 1 ml reagent 3, 0.25 ml reagent 4 and 0.05 ml reagent 5, incubated for 15 min.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Supernatants from each group of samples were collected, and the quantification of total GSH (GSH + GSSG) was performed by monitoring the formation of 2‐nitro‐5‐thiobenzoic acid at 412 nm.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
To determine GSSG specifically, the supernatants were derivatized using 1‐methyl‐2‐vinylpyridium trifluoromethane sulfonate.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Standard curves were established for both GSH and GSSG, and the concentration of GSH was calculated by subtracting the GSSG concentration from the total GSH (GSH + GSSG).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The measured concentrations of GSH and GSSG were then expressed as a ratio (GSH/GSSG).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Total RNA was extracted using Trizol (Yeasen Biotechnology Shanghai, China) and reverse-transcribed into cDNA.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
quantitative real-time polymerase chain reaction was carried out using the SYBR Green kit.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The relative mRNA expression was performed using the 2 method.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
GAPDH was used as internal control and the primers used are specified in Table S1.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Protein stability was determined by using the cycloheximide (CHX) chase assay.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Cells were treated with 100 μg/mL CHX for various time intervals after overexpression of STUB1.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Then GPX4 protein lysates were resolved on SDS-PAGE and analyzed by Western blotting.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Co-immunoprecipitation (CO-IP) assay was performed using the protein binding IP kit (abs955, Absin).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Cell lysates were first incubated overnight with anti-STUB1 (Abcam), anti-GPX4 (Proteintech), or control IgG (Cell Signaling Technology) at 4 °C overnight, and then incubated with protein A/G-agarose beads at 4 °C for 4 h. The precipitates were washed five times in a wash buffer and evaluated using Western blot analysis.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Western & IP lysis buffer (P0013, Beyotime) supplemented with the protease inhibitor and phosphatase inhibitors (#524625 and #539131, Millipore) was used to lyse cells on ice for 30 min.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The PVDF membranes (ISEQ00010, Millipore) were blocked with 5% skimmed milk at room temperature for 1 h, followed by incubation with primary antibodies at 4 °C overnight.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Then the membranes were washed 5 times for 5 min with TBST (TBS with 0.1% Tween 20) and incubated with HRP-conjugated secondary antibodies (CST, MA, USA) at room temperature for 1 h. The antibodies and the concentrations used are listed in Table S2.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The membrane was then washed and visualized using enhanced chemiluminescence (ECL) solution (Millipore, Beverly, USA) and analyzed using ImageJ software (Version 1.53, National Institutes of Health, Bethesda, MD).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Tissue microarray (TMA) containing 418 paraffin-embedded primary GIST surgical samples resected at our hospital between January 2014 and January 2021 with Institutional Review Board approval were constructed.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Informed consent was obtained from all subjects.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Immunohistochemistry (IHC) staining was performed with anti-STUB1 and anti-GPX4 antibodies.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The antibodies and the concentrations used are listed in Table S2.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The staining intensity and the proportion of positively stained cells were evaluated using Image J 1.53 software.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The staining intensity was graded as follows: negative = 0, mild = 1, moderate = 2, and strong = 3.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The proportion of positively stained cells was scored as follows: 1 = 0–24% positive cells; 2 = 25–49% positive cells; 3 = 50–74% positive cells; and 4 = 75%-100% positive cells.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The IHC staining score was expressed by the intensity multiplied by the proportional score.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
A staining score of <8 was regarded as the low expression group and that ≥8 as the high expression group.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Cultured cells were fixed using 4% paraformaldehyde (Sigma-Aldrich, #30525–89–4) in PBS for 20 min.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Subsequently, they were permeabilized with 0.3% Triton X-100 (Sigma-Aldrich, #9036–19–5) in PBS for 10 min and then blocked with 10% normal goat serum (Beyotime, #C0265, Jiangsu, China) for 1 h at 37 °C.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
This was followed by overnight incubation at 4 °C with primary antibodies against STUB1 (Abcam, #ab134064, 1:250) and GPX4 (Abcam, #ab125066, 1:200).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Afterwards, the cells were washed three times with PBS containing Tween 20 and then incubated with fluorescent secondary antibodies for 1 h at 37 °C.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The secondary antibody for STUB1 was green fluorescent, and the secondary antibody for GPX4 was red fluorescent.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Subsequent to this, the cells were rinsed three times with PBS and cell nuclei were stained with 1 μg/ml DAPI (Sigma-Aldrich, #D9542) for 10 min.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Image acquisition was performed using Zeiss LSM780 Laser Scanning Confocal Microscopy (Carl Zeiss, Jena, Germany).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
To quantitatively analyze colocalization, ImageJ software (Version 1.53, National Institutes of Health, Bethesda, MD) was utilized in conjunction with the Colocalization Finder plugin for calculating Pearson’s correlation coefficients .
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
GIST cells were initially seeded in 6-well CultureSlides obtained from BD Biosciences (Mountain View, CA, USA).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The cells were then fixed using 4% paraformaldehyde for a duration of 15 min and subsequently permeabilized with a solution consisting of 0.5% Triton X-100 in PBS for 30 min.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The slides were further processed for an in situ Proximity Ligation Assay following the manufacturer’s instructions, employing the Duolink® II Detection Reagents Green, Duolink® II PLA probe anti-Rabbit Minus, and Duolink® II PLA probe anti-Mouse Plus (Olink Bioscience, Uppsala, Sweden).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Primary antibodies used were STUB1 (Abcam, #ab134064) and GPX4 (Proteintech, #67763–1-Ig).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The resulting images were captured using Zeiss LSM780 Laser Scanning Confocal Microscopy (Carl Zeiss, Jena, Germany).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Subsequent quantification was performed using ImageJ software (Version 1.53, National Institutes of Health, Bethesda, MD).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Animal studies were reviewed and approved by the Institutional Review Boards of Zhongshan Hospital.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
GIST-T1 xenografts were established in 6-week-old male BALB/c nude mice (Shanghai Jiesijie Laboratory Animal Corporation) by inoculating 5 × 10 cells mixed with Matrigel (BD Biosciences) at a 1:1 ratio (volume) into the dorsolateral side.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
When the tumor reached 50mm, the mice were assigned randomly into DMSO, IM, RSL3, and IM combined with RSL3 groups.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
IM was dissolved in dimethyl sulfoxide (DMSO, #HY-Y0320, MCE), and diluted in PBS.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
RSL3 was dissolved in DMSO, diluted in corn oil (#HY-Y1888, MCE), and then intraperitoneally injected into mice with IM (100 mg/kg) or RSL3 (10 mg/kg) every 3 days.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The dosages of IM and RSL3 were determined based on previous studies and our own preliminary experimental results.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Tumor sizes were measured every 3 days, and tumor volumes were calculated as follows: 0.5×length×width.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Each group consisted of 6 mice.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
All mice were euthanized after 18 days of treatment, and the tumors were surgically excised.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
A portion of the tumors was immediately fixed in 4% paraformaldehyde, and sectioned for histological hematoxylin–eosin (HE) (Zhongshanjinqiao, Beijing, China) and IHC staining.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Experimenters were not blind to experimental groups.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
No pre-test analyses were used to estimate sample sizes.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
No data were excluded from the final analyses.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The reagents used and their commercial sources are indicated as follows: Dimethyl sulfoxide (#HY-Y0320), Corn oil (#HY-Y1888), Imatinib Mesylate (IM) (#HY-50946), RSL3 (#HY-100218A), Ferrostatin-1 (#HY-100579), MG-132 (#HY-13259) and Cycloheximide (CHX, #HY-12320), all of which were purchased from Med-Chem-Express (MCE; Shanghai, China).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Categorical variables are expressed as percentages and compared using the χ2 test and Fisher’s exact tests when appropriate, while continuous variables were presented as means ± standard deviation (SD) and compared using a double-tailed Students’ t test.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The number of animals and experimental repeats is listed in individual legends.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Data meets the assumptions of the tests.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The sample variation within each group was estimated to ensure that the variance is similar.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
All statistical tests were two-sided and statistically significance was declared when the P-value was ≤ 0.05.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Error bar = mean ± standard deviation in all graphs.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Statistical analyses were performed using GraphPad Prism (version 8.0.2, San Diego, USA).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
First, we investigated the sensitivity of GIST-T1 and GIST-882 cells to IM.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The CCK-8 results showed that the IC50 was 80 nmol (GIST-T1) and 263 nmol (GIST-882) (Fig. 1A).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The experimental doses of Ferrostatin-1 blocked the death of GIST-T1 and GIST-882 cells treated with RSL3, indicating the existence of ferroptosis in GIST (Fig. S2).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Moreover, we examined whether Ferrostatin-1 could reverse the inhibitory effect of IM, and found that Ferrostatin-1 could partially rescue the inhibitory effect of IM on both GIST-T1 and GIST-882 cells (Fig. 1B).Fig.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
1Imatinib (IM) induces ferroptosis in gastrointestinal stromal tumor (GIST) cells.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
A GIST-T1 and 882 cells were treated with different concentrations of IM for 24 h and the IC50 of IM was determined.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
B GIST-T1 and 882 cells were treated with IM (50 nM for T1 and 200 nM for 882) for 24 h in the absence or presence of Ferrostatin-1 (1 μM), and the cell viability was assayed.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
C Cell morphology was observed via transmission electron microscopy after the cells were treated with IM (50 nM for T1 and 200 nM for 882) for 24 h. The area of mitochondria are quantitatively analyzed by using the ImageJ software.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
D, E GIST-T1 and 882 cells were treated with IM (50 nM for T1 and 200 nM for 882) in the absence or presence of Ferr-1 (1 μM) for 12 h, the relative lipid ROS levels were measured using a C11-BODIPY lipid peroxidation sensor via confocal microscope (D) and flow cytometry (E).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
In fluorescence images, the increase in lipid ROS levels resulted in the oxidation of the polyunsaturated butadienyl portion of C11-BODIPY, causing a shift in fluorescence from red to green.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Flow cytometry analysis utilized the FITC filter for oxidized C11-BODIPY (emission: 510 nm) and the PE-TexasRed filter for reduced C11-BODIPY (emission: 590 nm).
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
The results are presented as a ratio of oxidized to reduced C11-BODIPY.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
F GIST-T1 and 882 cells were treated with IM at 0, 25, 50, and 100 nM and 0, 100, 200, and 400 nM for 24 h, and the relative levels of Fe were assayed.
PMC10728200
Imatinib induces ferroptosis in gastrointestinal stromal tumors by promoting STUB1-mediated GPX4 ubiquitination
Scale bar, 50 μm in D. Experiments were independently repeated three times.