NCI-H522 Xenograft Model
Lung cancer is primarily developed in the older population (over 65 years old). The chance of developing lung cancer in the US is approximately 1 in 16, with the risk being significantly higher for smokers. Approximately 14 percent of all new cancer diagnoses are lung cancer, which has two primary classifications: small cell and non-small cell lung cancer (NSCLC), of which large cell carcinoma (LCC) is a subtype. LCC cells are undifferentiated and lack characteristics of adenocarcinomas, squamous cell carcinomas, glandular cells or small cell carcinomas. Lung cancer is the deadliest type of cancer and is the number one in cancer related deaths. The NCIH522 cell line was isolated from a 58 year old smoker patient with stage 2 lung NSCLC by A.F. Gadzar. The patient obtained no prior therapy. NCIH522 cells have since been used in many lung cancer studies. The 1997 Japanese Journal of Cancer Research article used NCIH522 xenografts to characterize the efficacy of paclitaxel against various lung cancer types. Paclitaxel treatment was investigated in vitro as well as in vivo and in both cases results demonstrated significant growth inhibition. Today, paclitaxel is a chemotherapy used in a number of cancers including lung, breast and ovarian cancers. In a 2015 Journal of Biological Chemistry article, Staquicini et al. used the NCIH522 model to investigate the role of EphA5, an overexpressed tyrosine kinase receptor, in lung cancer. Results showed that EphA5 interacts with ATM in the nucleus during DNA repair and that EphA5 knockdown resulted in increased radiosensitivity and DNA damage as well as a defective checkpoint. A monoclonal antibody against EphA5 was also confirmed to cause similar radiosensitivity in vitro as well as in vivo. Lastly, Alley et al. (Cancer Research, 2004) used NCIH522 xenografts in a cancer cell line panel to evaluate the antitumor efficacy of SJG-136 (NSC 694501), an agent designed to cross-link interstrand DNA in the minor grooves. Results confirmed the previous in vitro reports of cytotoxicity as evidenced by tumor growth inhibitions in xenografts. The NCIH522 cell line is used to create the CDX (Cell Line Derived Xenograft) NCIH522 xenograft mouse model. The NCIH522 xenograft model has been used as a model for studying therapies (paclitaxel, anit-EphA5 monoclonal antibody, DNA crosslinking agent) for NSCLC.
Basic Study Design
- NCIH522 cells are maintained in exponential growth phase under aseptic conditions.
- Cells are trypsinized and cell count viability is determined using a trypan blue exclusion assay (98% of cell viability is required). NCIH522 cell suspension is adjusted to appropriate density.
- Each mouse is singly subcutaneously injected into the right flank with 106 cells in 100 µL of a NCIH522 cell suspension.
- The injection sites are palpated up to three times weekly until tumors are established to an average size of 50-150 mm3 as measured via digital calipers.
- Animals are randomized into treatment groups. Administration of test compound is performed according to the pre-established treatment schedule.
- Mice weights are measured and recorded 3 times weekly; tumors are measured and recorded daily.
- End of study is reached when tumor size reaches 2,000 mm3 or the predetermined size limit per approved IACUC protocol.
- Final necropsy and tissue collections are performed for appropriate downstream analysis. Tumors are excised, weighed and documented by digital imaging. Tumors and tissues can be stabilized in RNAlater, snap frozen in LN2 or prepared for histology.