Improvement of subcutaneous CDX model of lung cancer using A549 cell line

e15618 Background: Lung cancer is a challenging cancer problem, despite significant progress in its therapy. The search of drugs for the treatment of lung cancer is an urgent task. The creation of animal models of lung cancer plays a key role in preclinical trials and in understanding the mechanisms of tumor pathogenesis. The purpose of the study was to create a subcutaneous cell line-derived xenograft (CDX) model of lung cancer using the human lung cancer cells A459 and to compare results of subcutaneous injections of a cell suspension with different numbers of cells in two groups of animals. Methods: A CDX model of lung cancer was created using the human lung cancer cells A459 and male BALB/c Nude mice divided into two groups (n = 4 and n = 6) with subcutaneous injections of a mix of a cell suspension with Matrigel (200 μl). The injection mix contained 5*106 cells in 100 μl of serum-free RPMI-1640 medium and 100 μl of Matrigel (n = 4) and 10*106 cells in 100 μl of serum-free RPMI-1640 medium and 100 μl of Matrigel (n = 6). Results: Animal models receiving a suspension of 10*106 cells in 100 μl of serum-free RPMI-1640 medium and 100 μl of Matrigel were characterized by a higher tumor growth index compared to animals receiving 5*106 cells in 100 μl of serum-free RPMI-1640 medium and 100 μl of Matrigel. Models created with the injections of 10*106 cells showed a larger volume of tumor nodes: 65.33±1, 39.2±1, 41.79±1, 36.64±1, 75.87±1 and 43.13±1 mm3. CDX models created with the injections of 5*106 cells were characterized by a division of the single tumor node by the 30th day of the experiment which complicated the measurement. Conclusions: The creation of a CDX model with injections of 5*106 cells is undesirable due to the nonlinear growth of the xenograft and its division into several tumor nodes. Subcutaneous CDX models of lung cancer created with injections of 10*106 cells showed the linear growth and the formation of the single tumor node.