PNAs: To explore the "deadliest" lung cancer, scientists found a new application of crispr-cas9 system

Author: Wang Fang's small cell lung cancer (SCLC) is a kind of neuroendocrine tumor which is easy to recur and has a high degree of malignancy, accounting for about 15% - 20% of lung cancer Small cell lung cancer is often difficult to cure because it is likely to have spread widely when diagnosed Although large-scale sequencing studies have found many recurrent mutations in human SCLC tumors, we still know little about their functions However, this situation may be broken in the near future A research team of MIT applied crispr-cas9 system to the study of target gene mutation in small cell lung cancer, and found that p107 plays a role of tumor suppressor gene in SCLC The loss of p107 and its close relatives p130 leads to obvious tumor phenotype Https://doi.org/10.1073/pnas.1821893117 p107 and p130 are members of the retinoblastoma protein family, both of which are mutated repeatedly in about 6% of human SCLC tumors The researchers adapted crispr-cas9 system into a mature mouse model of SCLC, and verified the feasibility of this method in SCLC by simulating the loss of p107 and p130 in Trp53 / RB1 After 5.5 months of tumor occurrence, the researchers isolated genomic DNA from the tumors of infected animals, and then sequenced the corresponding sgRNAs targeted genomic sites in a targeted depth It was found that most of the detected sequences contained frameshift insertion or deletion, and each tumor had 1-4 different mutant alleles, which verified the use of crispr-cas9 system for SCLC candidates It is proved that p107, like p130, is a functional tumor suppressor in SCLC (loss of p107 accelerates tumor progression in SCLC) in further experiments, the researchers observed that sgp107 infected animals also showed a higher incidence of mediastinal lymph node metastasis in late cancer than sgp130 infected animals Compared with p130 deletion, p107 deletion leads to the change of the distribution of early lung tumor Subsequently, the researchers increased the measurement of phosphorylated histone H3 (phh3) staining to analyze the proliferation and apoptosis rates in two groups of animal tumors The results showed that the advanced tumors from sgp107 infected animals showed a higher proliferation rate Interestingly, this difference was not observed in early tumors The experimental data showed that compared with the loss of p130, the loss of p107 had a significant effect on the development of SCLC This study proved the feasibility of using crispr-cas9 system to simulate tumor suppressor gene loss in SCLC mouse model, which opened the door to verify the function of other candidate genes frequently mutated in SCLC, and will also help to verify the therapeutic target of SCLC in the future Jeni turtle