Responsiveness to basement membrane extract as a possible trait for tumorigenicity characterization

Area of Science:

• Biotechnology
• Cell Biology
• Vaccinology

Background:

• Immortalized cell lines are crucial for vaccine production and require tumorigenicity assessment.
• Current in vivo tumorigenicity assays are lengthy and can yield ambiguous results, particularly for weakly tumorigenic cells.
• Basement membrane extract (BME), a component of Engelbreth-Holm-Swarm mouse tumor, has been utilized in cancer research to augment tumorigenicity evaluations.

Purpose of the Study:

• To evaluate the feasibility of employing BME to streamline the assessment of vaccine cell substrate tumorigenicity.
• To investigate whether BME enhances the tumorigenicity of various cell lines relevant to vaccine production.

Main Methods:

• Low-passage (Vero LP) and high-passage (Vero HP) Vero cells, along with tumorigenic Vero derivatives (TPX2, NM1), HeLa, MDCK, 293, and ARPE-19 cells, were used.
• Cells were injected subcutaneously into athymic nude mice, both with and without the addition of BME.
• Tumorigenicity was assessed by observing tumor formation, latency, and the dose required for tumor production.

Main Results:

• BME did not enhance the tumorigenicity of ARPE-19 cells or Vero cells (Vero LP, Vero HP) previously characterized as non-tumorigenic or weakly tumorigenic.
• In contrast, BME significantly reduced tumor latency and the tumor-producing cell dose for HeLa, 293, and MDCK cells, as well as for the tumorigenic Vero derivatives TPX2 and NM1.
• The differential response to BME suggests it can distinguish between cell lines with varying degrees of neoplastic progression.

Conclusions:

• Responsiveness to BME may serve as a valuable indicator reflecting the neoplastic status of a cell line.
• This assay could potentially offer a more refined method for characterizing the tumorigenic phenotype of cells used in vaccine manufacturing.
• BME-enhanced assays may improve the efficiency and clarity of tumorigenicity evaluations for vaccine cell substrates.