RESUMO
China is a country with high incidence of esophageal cancer. In recent years, with the deepening research, the value of neoadjuvant therapy in locally advanced resectable esophageal cancer has been widely approved by clinicians, compared with surgery alone or adjuvant therapy. However, the survival results of different neoadjuvant therapy options may be quite different, and many problems remain unresolved. In this article, a systemic literature review was carried out to summarize the radiotherapy target, radiotherapy dose, chemotherapy regimen of neoadjuvant chemoradiotherapy and time to surgery, as well as review the research status and progress on targeted therapy and immunotherapy as neoadjuvant therapy for esophageal cancer.
RESUMO
The phenylacetone monooxygenase, isolated from Thermobifida fusca, mainly catalyzes Baeyer-Villiger oxidation reaction towards aromatic compounds. Met446 plays a vital role in catalytic promiscuity, based on the structure and function of phenylacetone monooxygenase. Mutation in Met446 locus can offer enzyme new catalytic feature to activate C-H bond, oxidizing indole to finally generate indigo and indirubin, but the yield was only 1.89 mg/L. In order to further improve the biosynthesis efficiency of the whole-cell catalyst, metabolic engineering was applied to change glucose metabolism pathway of Escherichia coli. Blocking glucose isomerase gene pgi led to pentose phosphate pathway instead of the glycolytic pathway to become the major metabolic pathways of glucose, which provided more cofactor NADPH needed in enzymatic oxidation of indole. Engineering the host E. coli led to synthesis of indigo and indirubin efficiency further increased to 25 mg/L. Combination of protein and metabolic engineering to design efficient whole-cell catalysts not only improves the synthesis of indigo and indirubin, but also provides a novel strategy for whole-cell catalyst development.