Related Experiment Video
Updated: Aug 1, 2025
Detection of a Circulating MicroRNA Custom Panel in Patients with Metastatic Colorectal Cancer
Published on: March 14, 2019
Secretome Screening of BRAFV600E-Mutated Colon Cancer Cells Resistant to Vemurafenib
Iris Car1, Antje Dittmann2, Marko Klobučar1
1Centre for Applied Bioanthropology, Institute for Anthropological Research, Ljudevita Gaja 32, 10000 Zagreb, Croatia.
Abstract:
Patients with metastatic colorectal cancer (mCRC) carrying BRAFV600E mutation have worse response to chemotherapy and poor prognosis. The BRAFV600E inhibitor vemurafenib has shown modest efficacy as monotherapy in BRAF-mutated mCRC due to the development of resistance. The aim of this study was to conduct a comparative proteomics profiling of the secretome from vemurafenib-sensitive vs. -resistant colon cancer cells harboring BRAFV600E mutation in order to identify specific secretory features potentially associated with changes in the resistant cells' phenotype. Towards this aim, we employed two complementary proteomics approaches including two-dimensional gel electrophoresis coupled with MALDI-TOF/TOF mass spectrometry and label-free quantitative LC-MS/MS analysis. Obtained results pointed to aberrant regulation of DNA replication and endoplasmic reticulum stress as the major secretome features associated with chemoresistant phenotype. Accordingly, two proteins implicated in these processes including RPA1 and HSPA5/GRP78 were discussed in more details in the context of biological networks and their importance as potential secretome targets for further functional and clinical evaluation. Expression patterns of RPA1 and HSPA5/GRP78 in tumor tissues from colon cancer patients were also found in additional in silico analyses to be associated with BRAFV600E mutation status, which opens the possibility to extrapolate our findings and their clinical implication to other solid tumors harboring BRAFV600E mutation, such as melanoma.
Insights
Vemurafenib resistance in BRAF-mutated colorectal cancer involves altered secretomes, specifically DNA replication and ER stress pathways. Targeting RPA1 and HSPA5/GRP78 may overcome resistance in BRAFV600E-mutated cancers.
Area of Science:
- Oncology
- Proteomics
- Molecular Biology
Background:
- Metastatic colorectal cancer (mCRC) with BRAFV600E mutation shows poor response to chemotherapy and prognosis.
- Vemurafenib, a BRAFV600E inhibitor, has limited efficacy in BRAF-mutated mCRC due to resistance.
- Identifying resistance mechanisms is crucial for improving treatment outcomes.
Purpose of the Study:
- To compare the secretomes of vemurafenib-sensitive and -resistant BRAFV600E-mutated colon cancer cells.
- To identify specific secretory proteins associated with chemoresistance.
- To explore potential therapeutic targets for overcoming vemurafenib resistance.
Main Methods:
- Comparative secretome profiling using two-dimensional gel electrophoresis with MALDI-TOF/TOF MS and label-free quantitative LC-MS/MS.
- Analysis of protein expression patterns in tumor tissues via in silico methods.
- Investigation of RPA1 and HSPA5/GRP78 in biological networks.
Main Results:
- Aberrant regulation of DNA replication and endoplasmic reticulum (ER) stress were identified as key secretome features in resistant cells.
- Proteins RPA1 (DNA replication) and HSPA5/GRP78 (ER stress) were significantly implicated.
- In silico analysis linked RPA1 and HSPA5/GRP78 expression to BRAFV600E mutation status in colon cancer patients.
Conclusions:
- Secretome alterations, particularly in DNA replication and ER stress, contribute to vemurafenib resistance in BRAFV600E-mutated mCRC.
- RPA1 and HSPA5/GRP78 represent potential therapeutic targets for overcoming resistance.
- Findings may be relevant for other BRAFV600E-mutated solid tumors, including melanoma.
