Higher than 20-fold levels of expression (p < 0.01) was sustained in LD 10–87 VERO cells at p250 and

in A4497 (p > 200) VERO cells, which are tumorigenic in both newborn and adult nude mice [10]. Three of the six miRNAs (miR-376a, miR-543 and miR-299-3p) were overexpressed more than 4-10 fold compared with pAGMK control cells and the LD 10–87 VERO cell passages before the expression of the tumorigenic phenotype was detected at p194 ( Table 1 and Fig. 1A). These results suggest that these miRNA-based biomarkers may be capable of predicting the pre-tumor stages of neoplastic development in VERO cells. To verify the accuracy and specificity of these results, we assessed the six miRNAs in HD VERO cells that were passaged independently at higher, confluent densities. The trend in the alteration of miRNA expression was generally similar Sirolimus between the LD 10–87 VERO cell lines and the HD 10–87 VERO cell lines. When compared with the pAGMK controls, five of these six miRNAs were over-expressed by greater than 4-fold in the tumorigenic PKC signaling HD 10–87 VERO cells at p183, and all six were

over-expressed by 6- to >50-fold at p250 ( Table 2). To further evaluate the ability of individual miRNA to reflect the expression of the tumorigenic phenotype in VERO cells, we examined three miRNA data sets (miR-376a, miR-654-3P, and miR-543) from experiments shown in Table 1 and Table 2. The expression pattern of each of these miRNA followed the progression of neoplastic development and peaked at p194 (Fig. either 4A) where the ability of LD 10–87 VERO cells

to form tumors was detected (Fig. 1). In HD 10–87 VERO cells, the same association between elevated expression levels of the same miRNAs and tumorigenicity was observed at p183; however, the expression levels in cells at p250 increased by an additional 4-fold compared with cells at p183 (Fig. 4B). Together, regardless of how the tumor-forming cells were established, whether by passaging at low density or high density, the individual miRNA expression pattern correlated with the detection of the tumorigenic phenotype. Therefore, these six miRNAs appeared to be biomarkers for this property of VERO cells. Managing the threats posed by emerging and re-emerging infectious diseases, such as pandemic influenza, call for the rapid production of large, possibly unprecedented, amounts of vaccines to immunize populations worldwide [31], [32] and [33]. Current production methods may be insufficient to meet these demands in the short period required to manage pandemics successfully [33]. Cell-culture technology based on immortalized cell substrates provides a possible method for increasing the efficiency of vaccine manufacture and improving vaccine efficacy [1], [3], [6], [8], [31], [32], [34], [35], [36] and [37]. Regulatory agencies have recommended that the tumorigenic potential of immortalized cell substrates proposed for human vaccine production be evaluated (21 Code of Federal Regulations 610.18).