PMCID
string
Title
string
Sentences
string
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
The Golgi complex is a specialized organelle for protein processing and trafficking .
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Currently, little is known about the function of the Golgi complex, specifically as a platform for initiating receptor tyrosine kinase (RTK) signaling.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
It was demonstrated that MT-KIT directly recruits P85 and GRB2 to the Golgi complex, and its loss in the Golgi complex drastically perturbs downstream signaling.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Herein, we propose a Golgi-based signaling model for MT-KIT.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Since the Golgi complex is not central to protein quality control, this unique form of signaling that hides RTK in the Golgi complex would be advantageous for cancer cells, as there is always a risk that mutant RTKs in the ER or PM are degraded through ERQC and PMQC.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Mutations in KIT are most frequently detected in exon 11 (juxtamembrane domain, 70%), followed by exon 9 (extracellular domain, 10%) and less frequently in exon 13 (adenosine triphosphate (ATP)-binding pocket, 1%), or in exon 17 (activation loop, 1%) .
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Since GIST430, GIST882, GIST48, and GIST430-V654A cells commonly displayed Golgi-localization of MT-KIT regardless of mutation type, we suspected that GIST might have acquired a complementary mechanism for Golgi-retention of MT-KIT.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
BLZF1, a Golgi resident protein , was found to be important in tethering MT-KIT in the Golgi complex and thereby for GIST survival.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Considering its selective and high expression in GIST, BLZF1 should be further characterized as a druggable target for GIST treatment.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
To rationalize the localization of MT-KIT in the Golgi complex, ERQC bypass of MT-KIT should be preceded.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
As a large solid tumor, GIST undergoes chronic ER stress conditions, such as insufficient nutrients and hypoxia, that eventually induce ERQC and cell death [30–32].
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Cancer cells alleviate ER stress by initiating the UPR system that usually leads to mutant protein degradation by ERQC.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
However, this mechanism might be disadvantageous for cancer cells because of the loss of driver oncoproteins, such as MT-KIT .
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Therefore, promoting folding rather than degrading mutant proteins may be favorable for long-term cancer progression.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Results of this study show evidence that GIST has developed an ATF6-dependent UPR activation mechanism to ameliorate ER stress.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Sustained activation of ATF6 was detected in all GIST cell lines and frequently in the patients’ tissues.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
This unique ER stress-protective environment allows GISTs to resist ER stress to some extent.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Pharmacological inhibition of ATF6 significantly decreased chaperone expression, including HSP90, and resensitized GIST cells, even under mild ER stress.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
The ATF6-HSP90 axis is especially beneficial for GIST tumorigenesis in a manner of MT-KIT folding and ERQC bypass of MT-KIT.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
This finding is consistent with previous research showing that 17AAG and TAS-116, HSP90 inhibitors, effectively suppress GIST growth .
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
HSP90 inhibitors have a different mechanism of action from kinase activity inhibition, such as that seen with imatinib.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Instead, they fundamentally downregulate mutant KIT expression.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
This mechanism sets them apart from imatinib, as it makes these drugs irrelevant to the generation of secondary mutations that can weaken the antitumor effect.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
By targeting mutant KIT expression itself, HSP90 inhibitors offer a promising approach for GIST treatment that may overcome imatinib resistance mechanisms associated with secondary mutations.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Moreover, previous studies have suggested that sustained activation of ATF6 is a prosurvival mechanism in various cancer types such as melanoma, glioblastoma, and hepatocellular carcinoma [35–37].
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Based on these findings we propose that HSP90 inhibitors, either alone or in combination with ATF6 inhibitors, hold great promise as alternative treatments for GIST.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
In vitro and in vivo experiments clearly demonstrated that ATF6 inhibition is a promising strategy for GIST treatment, and combined treatment with ER stress-inducing drugs further enhances the antitumor efficacy.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
This treatment strategy showed invariable effects even on imatinib-resistant GIST, which is a major challenge in clinical practice.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Although there are no FDA-approved regimens for targeting ATF6 in cancers, three reported ATF6 inhibitors with different modes of action have shown great efficacy .
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Notably, melatonin, a relatively safe dietary supplement, effectively suppressed GIST growth at a generally safe concentration (1 mM) and showed synergistic effects with ER stress-inducing drugs.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Although melatonin use for GIST treatment requires intensive in vivo and clinical validation, this strategy could be practical since no severe side effects were reported for melatonin.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Considering that sustained activation of ATF6 is exclusively observed in GIST and that the ATF6-HSP90 axis plays a crucial role in MT-KIT stabilization, we propose that ATF6 is a promising multi-effect target for GIST treatment, at least for imatinib-resistant patients with no other therapeutic options.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
In conclusion, this study provides evidence that GIST has developed highly coordinated survival strategies of hiding MT-KIT in the quality control-free Golgi complex, and developing an intrinsic ER stress resistance mechanism (summarized in Fig. 6).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Our findings provide insights into future GIST treatment strategies.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Therapeutic antibodies targeting membranous MT-KIT might be challenging.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
BLZF1 and ATF6 pathway could be promising drug targets for GIST treatment.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Fig. 6Schematic representation of novel GIST tumorigenesis mechanisms via the Golgi-localized MT-KIT-mediated oncogenic signaling and constant activation of pro-survival ATF6 dependent UPR signaling.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Schematic representation of novel GIST tumorigenesis mechanisms via the Golgi-localized MT-KIT-mediated oncogenic signaling and constant activation of pro-survival ATF6 dependent UPR signaling.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
In-depth mechanistic and clinical studies are crucial to enhance our understanding of whether targeting BLZF1 and ATF6 could overcome the limitations of conventional therapy in actual patients with GISTs.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Additionally, investigating the relationship between BLZF1 and ATF6 would provide valuable insights into their cooperative roles in GIST pathogenesis.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
It would be beneficial to utilize genomic and transcriptomic analysis data from patients with GIST to further advance our understanding.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Furthermore, leveraging the differential protein trafficking regulation between murine and human cells can be a valuable strategy for future studies in this field .
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
By incorporating these approaches, we can gain valuable insights that may lead to the development of improved therapeutic strategies for GIST patients.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
GIST430 (exon 11 in-frame deletion) and GIST430-V654A (exon 11 in-frame deletion and V654A) cells were cultured in Iscove’s modified Dulbecco’s medium (IMDM) supplemented with 15% fetal calf serum (Life Technologies, Carlsbad, CA, USA).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
GIST48 (V560D) cells were cultured in IMDM supplemented with 15% fetal bovine serum (FBS; Life Technologies).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
GIST882 (homozygous exon 13 K642E point mutation) cells were cultured in RPMI1640 with 15% FBS.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
GIST cell lines were established by Prof. Jonathan Fletcher (Boston, MA, USA).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Colon cancer cell lines (DLD-1, LS174T, Colo320DM) and small-cell lung cancer cell lines (H69, H128, H209) were cultured in RPMI1640 medium supplemented with 10% FBS.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
The leukemia cell lines K562 and Kasumi-1 were cultured in RPMI1640 medium supplemented with 10% FBS.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Another leukemia cell line, HMC-1, was cultured in IMDM medium supplemented with 15% FBS.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
A cervical cancer cell line (HeLa), pancreatic cancer cell line (Capan-1), and breast cancer cell line (MDA-MB-231) were used as KIT-negative cell lines.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
HeLa cells were cultured in Minimum Essential Medium supplemented with 10% FBS.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Capan-1 and MDA-MB-231 cells were cultured in RPMI1640 medium supplemented with 10% FBS.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Cell lines were authenticated by KIT sequencing and microscopic examinations.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
RT-qPCR and western blot was performed to monitor morphology, growth patterns, mutation status, and KIT expression.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Cell lines were screened bi-monthly to monitor for mycoplasma infections.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
For treatment reagents, GIST cells were treated with thapsigargin (TG; Sigma, St. Louis, MO, USA), bortezomib (Sigma), or 17AAG (Sigma) to mimic endoplasmic reticulum (ER) stress; Brefeldin A (BFA; Sigma) to inhibit ER-to-Golgi trafficking; Bafilomycin A1 (BAF; Sigma) to inhibit lysosomal degradation; cycloheximide CHX) to block translation; 30N12 (Chembridge, San Diego, CA, USA) to inhibit trans-Golgi-to-PM trafficking.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
PF429242 (Tocris, Ellisville, MO, USA), Ceapin-A7 (Sigma), and melatonin (Sigma) were used to inhibit ATF6 activation.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Imatinib mesylate (Sigma) was used as the control drug for GIST treatment.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
To construct GRB2 and p85 expression vectors with a hemagglutinin (HA) tag, GRB2 and p85 coding regions were amplified by PCR using cDNA from GIST430 cells, then cloned into a pCMV vector with an HA tag.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
The primers used to construct GRB2 and P85 expression vectors are listed in Supplementary Table S3.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Whole cell lysates were prepared using passive lysis buffer (Promega, Madison, WI, USA) with a protease inhibitor cocktail (Roche, Basel, Switzerland).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
The proteins were electrophoresed and transferred onto a membrane.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
The membranes were incubated overnight at 4 °C with primary antibodies against GAPDH (Trevigen, Gaithersburg, MD, USA), KIT (Dako or Cell Signaling Technology, Beverly, MA, USA), HA (Cell Signaling Technology), phospho-KIT (Cell Signaling Technology), AKT (Cell Signaling Technology), phospho-AKT (Cell Signaling Technology), ERK (Santa Cruz Biotechnology, Santa Cruz, CA, USA), phospho-ERK (Santa Cruz Biotechnology), P85 (Cell Signaling Technology), GRB2 (Cell Signaling Technology), GBF1 (BD Biosciences; NJ, USA), GM130 (BD Biosciences), Golgin97 (MyBioSource, San Diego, CA, USA), TGN38 (Bio-Rad Laboratories, Hercules, CA, USA), GRASP55 (Abcam), GRASP65 (Invitrogen, Carlsbad, CA, USA), BLZF1 (Novus Biologicals, Littleton, CO, USA), STX3 (Abcam), STX6 (Cell Signaling Technology), GOLPH3 (LifeSpan Biosciences, Seattle, WA, USA), ATF6 (Abcam), IRE1α (Cell Signaling Technology), phospho-IRE1α (Novus Biologicals), PERK (Cell Signaling Technology), phospho-PERK (Cell Signaling Technology), CHOP (Cell Signaling Technology), BIP (Cell Signaling Technology), GRP94 (Cell Signaling Technology), HSP70 (Abcam) and HSP90 (Cell Signaling Technology).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
The membranes were washed and incubated with the appropriate secondary antibodies for 1 h at room temperature.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Western blot images were analyzed using an LAS 4000 mini camera (Fujifilm, Tokyo, Japan).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
For immunoprecipitation assays, immune complexes of MT-KIT were collected by mixing 500 µg of GIST cell lysate with a KIT antibody (Cell Signaling Technology) and protein A/G PLUS-Agarose (Santa Cruz Biotechnology), then gently rocking on an orbital shaker at 4 °C overnight.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Immune complexes bound to agarose beads were washed and boiled with 3× NuPAGE LDS Sample Buffer (Thermo Fisher Scientific) to elute the complexes.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
The relative density of each band was quantified using ImageJ software (Ver 1.53 K; National Institutes of Health, MD, USA).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Formalin-fixed paraffin-embedded (FFPE) GIST tissue samples from 42 patients were used.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
All specimens were obtained via surgical resection, and some of the clinicopathological findings of the 42 GIST samples have been previously reported .
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
The specimens were obtained from the archives of the Department of Pathology, Yonsei University, Seoul, Korea and the Liver Cancer Specimen Bank of the National Research Resource Bank Program of the Korea Science and Engineering Foundation of the Ministry of Science and Technology.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Authorization for the use of these tissues for research purposes was obtained from the Institutional Review Board of Yonsei University, College of Medicine (IRB 4-2015-0227).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
For IHC analysis, 4 µm-thick sections were obtained from FFPE GIST tissue specimens obtained from 42 patients.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
IHC was performed using the Ventana Discovery XT autoimmunostainer (Ventana, Tucson, AZ, USA) with antibodies against KIT (1:200, Dako) and ATF6 (1:200, Abcam) according to the manufacturer’s standard protocol.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
IHC results were evaluated using an H-score method.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
The H-score method, which assigns an IHC H-score to each case on a continuous scale of 0–300 based on the percentage of cells at different staining intensities, was used for the interpretation of KIT and ATF6 results.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
The staining intensity was scored as follows: 0 = no staining; 1+ = weak staining visible at high magnification; 2+ = intermediate staining; 3+ = strong staining.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
The percentage of cells at different staining intensities was determined by visual assessment with scores calculated using the following formula: 1(% of 1+ cells) +2 (% of 2+ cells) +3 (% of 3+ cells).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Results were then classified as low (H-score ≤10) or high (H-score >10) protein level.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
DLD-1, Colo320DM, GIST430, and GIST882 cells were biotin-labeled for 30 min, washed extensively, and harvested for further analysis.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
To analyze membranous MT-KIT stability, GIST cells were harvested at predefined incubation times.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Subsequently, the labeled proteins were isolated and eluted using the Pierce Cell Surface Protein Isolation Kit (Thermo Fisher Scientific, Waltham, MA, USA) according to the manufacturer’s instructions.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Because of the low expression of membranous MT-KIT in GIST cells, biotinylation assays for GIST cells were performed with twice the amount of lysate compared to those used for DLD-1 and Colo320DM cells.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Cells grown on slides were rinsed with phosphate-buffered saline (PBS), fixed with 4% paraformaldehyde or 100% methanol for 15 min, and permeabilized in 0.2% Triton X-100 in PBS.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
The slides were incubated overnight at 4 °C with primary antibodies against KIT (Cell Signaling Technology), calnexin (Cell Signaling Technology), GM130 (Cell Signaling Technology), mannosidase II (Abcam), Golgin-97 (Cell Signaling Technology), HA (Cell Signaling Technology), BLZF1 (Novus Biologicals), LAMP1 (Cell Signaling Technology), and ATF6 (Abcam).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
The slides were then incubated for 1 h with the appropriate fluorescence-labeled secondary antibody (Life Technologies).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
All images were captured using an LSM700 confocal microscope (Carl Zeiss, Oberkochen, Germany).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Immunofluorescence intensity and colocalization among proteins were quantified using ImageJ software (NIH).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
GIST cells grown on slides were washed three times with ice-cold serum-free medium and incubated with KIT antibody conjugated with a fluorescent dye (Alexa Fluor 488, Cell Signaling Technology) in ice-cold serum-free medium for 30 min.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
The cells were washed with cold serum-free medium to remove excess antibodies and incubated at 37 °C for various timepoints.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Cells were fixed in 4% paraformaldehyde in PBS and processed for immunofluorescence analysis.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Colocalization of MT-KIT with EEA1 (Abcam), LAMP1 (Cell Signaling Technology), and GM130 (Cell Signaling Technology) was examined.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Cell viability was analyzed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
GIST cells were seeded in 96-well plates at a density of 3 × 10 cells/well and treated with PF429242, Ceapin-A7, or melatonin with or without thapsigargin, bortezomib, 17AAG, or imatinib for 72 h. MTT (5 mg ml) solution was then added to the plates and incubated at 37 °C for 4 h. After the formazan crystals were dissolved in DMSO, the OD was measured at 570 nm using a microplate reader.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
This experiment was performed with or without TG.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Highest single agent (HSA) synergy scores were calculated using SynergyFinder 2.0 (10.1093/nar/gkaa216).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
Short hairpin RNA (shRNA) against BLZF1 (gene ID: 8548) was purchased from the shRNA library of the RNAi Consortium (TRC) provided by the Yonsei Genome Center (Seoul, Korea).
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
GIST cells were transfected with the TRC2-pLKO-puro vector containing shRNA for BLZF1, and the MTT assay was performed 72 h after transfection.
PMC10589262
Identification of novel pathogenic roles of BLZF1/ATF6 in tumorigenesis of gastrointestinal stromal tumor showing Golgi-localized mutant KIT
All animal modeling procedures were approved by the Institutional Animal Care and Use Committee of the Catholic University of Korea (No. 2022-0037-05).