Project description:Immune checkpoint blockade is a powerful oncologic treatment modality for a wide variety of human malignancies. Randomized clinical trials are assessing how best to interdigitate this treatment modality with traditional therapies including radiotherapy. A challenge in oncology is to rationally and effectively integrate immunotherapy with traditional modalities including radiotherapy. Here, we demonstrate that radiotherapy induces tumor cell ferroptosis. Ferroptosis agonists augment and ferroptosis antagonists limit radiotherapy efficacy in tumor models. Immunotherapy sensitizes tumors to radiotherapy by promoting tumor cell ferroptosis. Mechanistically, IFN derived from immunotherapy-activated CD8+ T cells and radiotherapy-activated ATM independently, yet synergistically repress SLC7A11, a unit of the glutamate-cystine antiporter xc-, resulting in reduced cystine uptake, enhanced tumor lipid oxidation and ferroptosis, and improved tumor control. Thus, ferroptosis is an unappreciated mechanism and focus for the development of effective combinatorial cancer therapy.
Project description:Radiotherapy is essential to treat colorectal cancer (CRC) although the tolerance of which is of quite common occurrence in clinic. Long noncoding RNA (lncRNA) and circular RNA (circRNAs) have an important role in the radio-resistance of CRC through regulating targeted genes or proteins expression at either transcriptional or post-translational levels. In this study, we aimed to seek out novel lncRNAs and circRNAs involved in radio-resistance by RNA-seq analysis of 8 radiosensitive and 8 radioresistant CRC patients.
Project description:Colorectal cancer (CRC) is the third most common cancer worldwide and is a heterogeneous disease, with differences between cancer in the right colon, left colon, and rectum. In this study, plasma samples from CRC patients with varying stage (II or III), primary tumor location (right colon, left colon, or rectum) and survival (survived or died due to CRC) were studied with quantitative label-free proteomics using ultra-definition MSE. Patients were also divided into subgroups based on preoperative radiotherapy status and gender. Further analysis subsequently identified multiple plasma proteins whose expression differed depending on tumor stage, location, patient survival, preoperative radiotherapy status, or gender.
Project description:p53 mutation is common and highly related to radiotherapy resistance in rectal cancer. APR-246, as a small molecule, can restore the tumor-suppressor function to mutant p53. There is no study on combining APR-246 with radiation in rectal cancer; therefore, we examined whether APR-246 sensitized colorectal cancer cells with different p53 status to radiation. The combination treatment had synergistic effects on HCT116p53-R248W/-(p53Mut) cells, followed by HCT116p53+/+(p53WT) cells, and exhibited an additive effect on HCT116p53-/-(p53Null) cells through inhibiting proliferation, enhancing reactive oxygen species, and apoptosis. The results were confirmed in zebrafish xenografts. Comparison of the transcriptome in colorectal cancer cells with different p53 status 72hrs post-treatment with APR-246, irradiation, or the combination of APR-246 with irradiation was carried out. p53Mut and p53WT cells shared more activated pathways and differentially expressed genes following the combination treatment, compared to p53Null cells, although the combination treatment regulated individual pathways in the different cell lines. APR-246 mediated radio-sensitization effects through p53-dependent and -independent ways.
Project description:The molecular mechanisms of clinical response or resistance to therapy were evaluated in colorectal cancer patients in a prospective biomarker discovery project. Rectal adenocarcinomas, biopsied before (diagnostic biopsy) and after (surgical resection) pre-operative short-course radiotherapy [RT] or 5-flurouracil (5-FU)-based chemoradiotherapy [CRT], were profiled using Affymetrix HGU133 Plus 2.0 microarrays. Tumour tissues from untreated controls at diagnosis and surgical resection were used to identify treatment-independent gene expression changes. Candidate resistance biomarkers were identified in this pilot study for validation in a larger cohort.
Project description:gene expression profiling of locally invasive breast carcinomas treated with preoperative radiotherapy the purose of this study was to establish molecular signature associated with response to radiotherapy using radiotherapy-naïve biopsies of locally advanced breast cancer
