(T1130-04-23) The Response of an Orthotopic Lung Cancer Xenograft Model to Cisplatin

Purpose: As a critical indicator of anticancer drug development, animal models of cancer should be able to recapitulate its progression and predict its response to anticancer drugs that are used in clinic. Recently, our lab established a murine orthotopic lung cancer xenograft model that mimics four stages of non-small cell lung cancer by intrapulmonary inoculation of 3D multicellular tumor spheroids (MCS) [1]. This study aims 1) to monitor the burden of tumor xenograft to mice overtime; and 2) to study the response (toxicity and efficacy) of this model to cisplatin, a first-line drug against non-small cell lung cancer in clinic.

Methods: The orthotopic xenograft model was established as previously described [1]. Briefly, A549-iRFP MCS were cultured in Corning™ 96-Well, Ultra-Low Binding, U-Shaped-Bottom Microplate and the MCS with desirable morphology were inoculated into the left lung of mice. Animals bearing A549-iRFP MCS were imaged in four postural directions (left, right, ventral, and dorsal) twice a week on a Pearl® Trilogy small animal imaging system at the 700 nm channel. The tumor growth after MCS inoculation was quantified from the ventral-posture images using the Image Studio Lite Ver 5.2 software. Ten days after MCS inoculation, the tumor-bearing mice were treated with 5 mg/kg cisplatin or normal saline by tail vein injection once a week for two times. Their body weight and fluorescent signal from tumor xenograft were monitored twice a week.

Results: After successful MCS inoculation, the tumor xenograft inside mice kept growing and eventually metastasized into the other side of lung. After treatment with normal saline, the tumor growth caused substantial animal body weight loss (~15%, Figure 1) at Day 40. In comparison, mice’ body weight dropped significantly after each cisplatin treatment, which is an indicator of chemotherapeutic toxicity (Figure 2). After two injections, the cisplatin treatment slowed down tumor growth as well as tumor metastasis into the other side of the lung, indicating substantial chemotherapeutic efficacy (Figure 3).

Conclusion: The cancer progression in the orthotopic xenograft lung cancer model can be monitored by the fluorescent signal from the cancer cells for about 40 days. The model could respond well to the cisplatin treatment.

References: 1. Huang Y, Lu Y, Vadlamudi M, Zhao S, Felmlee M, Rahimian R, Guo X. Intrapulmonary inoculation of multicellular spheroids to construct an orthotopic lung cancer xenograft model that mimics four clinical stages of non-small cell lung cancer. J Pharmacol Toxicol Methods. 2020 Jul-Aug;104:106885. doi: 10.1016/j.vascn.2020.106885. Epub 2020 Jun 10. PMID: 32531198.
2. Yingbo Huang, Zizhao Xu, et al. Intrapulmonary Inoculation of Multicellular Tumor Spheroids to Construct an Orthotopic Lung Cancer Xenograft Model. Poster presentation, PHARMSCI 360, American Association of Pharmaceutical Scientists Annual Meeting and Exposition, 2020. Winner of 2020 AAPS Best Abstract Award.

Figure 1. The left-side and ventral-side in vivo imaging (A) and the mice’s body weight change after MCS inoculation (B) by normal saline, N = 8.

Figure 2. The ventral-side in vivo imaging (A) and the body weight of tumor-bearing mice after cisplatin or normal saline treatment (B). Red rectangles designate the inception of tumor fluorescence observed in both sides of the lung, indicating metastasis.

Figure 3. The response of the orthotopic xenograft lung cancer model to cisplatin treatment. The tumor growth (A) and the metastasis (B) after cisplatin treatment.