Is RPMI 2650 a Suitable In Vitro Nasal Model for Drug Transport Studies?

Abstract

The evaluation of new intranasal medications requires the development of in vitro cell model suitable for high-throughput screening studies. The aim of a pharmacological model is to closely mimic the barrier properties of human nasal mucosa that will influence drug pharmacokinetics. In this context, the human nasal cell line RPMI 2650 has been investigated over these last years. Although the initial studies tended to demonstrate strong physiological correlations between RPMI 2650 cells and nasal mucosa, the variability of experimental designs does not allow a clear comparison of actual data. Thereby, the standardization of cell culture parameters is crucial to obtain a stronger reproducibility and increase the relevance of data. Indeed, RPMI 2650 barrier properties are heavily dependent of cell culture conditions, especially of the physiological air-liquid interface that strengthen the expression of both tight junction proteins and drug transporters. Conversely, cell culture medium and insert composition showed a minor impact on the four key parameters of a nasal barrier. Despite the recent advances in the physiological characterization of RPMI 2650 model, only limited pharmacological data are available concerning the involvement of drug transporters in drug bioavailability. The deployment of standardized bi-directional permeability studies using reference compounds is required to determine the relevance of RPMI 2650 model in the field of drug transport studies.

Impact of Glycosylation and Species Origin on the Uptake and Permeation of IgGs through the Nasal Airway Mucosa

“…media . The cell line RPMI 2650 was derived from cancerous human nasal squamous epithelium and is currently used as a standard model for intranasal drug delivery since specimens of human nasal mucosa are unfortunately hardly available [ 47 , 48 , 49 ]. Comparable to the in vitro permeation through OEPC layers ( Figure 3 B), DG hIgG showed a higher permeation rate and flux than wild-type IgG in the RPMI 2650 ALI model ( Figure 3 A).…”

“…To exclude interspecies effects due to the use of human IgG in porcine tissue and cells, the permeation experiments were repeated using the nasal mucosa standard cell line RPMI 2650 [ 37 , 39 , 49 ]. The results from the OEPC model could be confirmed in the RPMI 2650 model, indicating again a cross-species mechanism for IgG trafficking.…”

Improved In Vitro Model for Intranasal Mucosal Drug Delivery: Primary Olfactory and Respiratory Epithelial Cells Compared with the Permanent Nasal Cell Line RPMI 2650

“…In theory, tumour cell lines are immortal, whereas primary cells are limited to a certain number of cell divisions [36]. However, most tumour cells lack the ability to fully differentiate into, e.g., ciliated or mucus producing cells, while primary cell cultures are morphologically and physiologically very close to their native state [26,37]. As factors such as cilia and mucus can possibly influence the drug uptake time and the bioavailability due to, e.g., enzymes even in stagnant cell culture, these are important parameters to consider for drug permeation evaluations.…”

“…Epithelial cell features such as the presence of cilia, mucus secretion and tight junction formation are important factors that influence the bioavailability of nasally applied drugs [7]. Generally, a heterogenic mixture of different cell types is preferred for a valid model, since this better represents the mucosal epithelial assembly in respect to the permeation profile of drugs through the cellular barrier [37,39]. Furthermore, cultured tumour cells tend to build multilayers, as their growth is mostly not limited by contact inhibition after reaching confluency, whereas primary cells remain in monolayers.…”

“…For epithelial barrier models, monolayers should be preferred as these resemble the natural epithelial structure more closely. Nevertheless, there are several studies proving the tumour cells line originating from nasal squamous epithelium (septum) RPMI 2650 is a suitable model for the nasal epithelium [20,21,26,37,40]. This cell line is closely related to normal human nasal epithelium in terms of its karyotype and the cytokeratin polypeptide pattern as well as the presence of mucus on the cell surface [34,35,41].…”