In vivo library screening identifies the metabolic enzyme aldolase A as a promoter of metastatic lung colonization

Proteomic response of A549 lung cancer cell line to protein-polysaccharide complex Venetin-1 isolated from earthworm coelomic fluid

Earthworms' celomic fluid has long attracted scientists' interest due to their toxic properties. It has been shown that the elimination of coelomic fluid cytotoxicity to normal human cells was crucial for the generation of the non-toxic Venetin-1 protein-polysaccharide complex, which exhibits selective activity against Candida albicans cells as well as A549 non-small cell lung cancer cells. To find the molecular mechanisms behind the anti-cancer properties of the preparation, this research investigated the proteome response of A549 cells to the presence of Venetin-1. The sequential window acquisition of all theoretical mass spectra (SWATH-MS) methodology was used for the analysis, which allows for a relative quantitative analysis to be carried out without radiolabelling. The results showed that the formulation did not induce significant proteome responses in normal BEAS-2B cells. In the case of the tumour line, 31 proteins were up regulated, and 18 proteins down regulated. Proteins with increased expression in neoplastic cells are mainly associated with the mitochondrion, membrane transport and the endoplasmic reticulum. In the case of altered proteins, Venetin-1 interferes with proteins that stabilise the structures, i.e., keratin, glycolysis/gluconeogenesis and metabolic processes.

In vivo gain-of-function cDNA library screening for colonization genes in a mouse model of pulmonary metastasis

We provide a protocol for gain-of-function (GOF) cDNA screen of genes that foster cancer cell colonization of secondary tissues, the last and most lethal step of the metastasis cascade. We present techniques for cDNA viral library preparation and delivery leading up to the recovery of colonization-promoting sequences in a proof-of-concept DU145-based mouse model of pulmonary metastasis. Adapted to other cDNA libraries and cancer models, this approach would prove widely useful in enumerating intrinsic genetic determinants underlying metastatic colonization.

For complete details on the use and execution of this protocol, please refer to Tu et al. (2021).

•

Colonization is the last and most lethal bottleneck step of the metastasis cascade

•

Gain-of-function (GOF) cDNA screen was adapted to probe cancer colonization of lung

•

DU145 cells harboring GOF prostate cDNA library generated pulmonary macro-metastases

•

Genomic PCR of macro-colonies exposed inserted cDNAs of potential colonization genes

Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.