# Mono‐ and Co‐Culture Biofilms of Candida auris or Candida albicans With Staphylococcus aureus Regulate Cell Viability and Pro‐Inflammatory Cytokine Expression Differently in Oral Cancer Cell Lines

## TL;DR

The study shows that co-cultures of Candida and Staphylococcus aureus affect oral cancer cells more than mono-cultures, increasing inflammation and reducing cell viability.

## Contribution

The novel finding is that co-cultures of Candida auris or Candida albicans with Staphylococcus aureus uniquely influence oral cancer cell behavior compared to mono-cultures.

## Key findings

- Co-cultures of C. auris and S. aureus significantly increased IL-6 and IL-8 expression in oral cancer cells compared to C. albicans.
- Co-culturing Candida species with S. aureus reduced cell viability and increased pro-inflammatory IL-8 expression in oral cancer cell lines.

## Abstract

Candida species and
Staphylococcus aureus
are nosocomial pathogens associated with immunocompromised individuals, especially oral cancer patients. This study elucidates the effects of mono‐ and co‐culture biofilms of
Candida albicans
, Candida auris and
S. aureus
on cell viability and pro‐inflammatory cytokine expression in healthy epithelial cells (hTERT TIGKs) and oral cancer (ORL‐48) cell lines.

Mono‐ and co‐culture biofilms of
C. albicans
,
C. auris
and
S. aureus
, developed using static biofilm for 72 h, were collected and filter sterilized (biofilm filtrate). Test cell growth medium (TCGM) was prepared for hTERT TIGKs and ORL‐48 by mixing 20% (v/v) biofilm filtrate with 80% serum‐free media. The cells were seeded in 96‐well plates, and TCGM was added as treatment. The unstimulated media (UM), made of 100% serum‐free media, served as control. After 24 h, cell viability was assessed using CCK‐8. Interleukin (IL)‐6 and IL‐8 expression was analysed using enzyme‐linked immunosorbent assay (ELISA).

S. aureus
consistently decreased cell vitality in co‐culture as compared to mono‐culture,
C. albicans
and
C. auris
in both cell lines. Co‐culture of
C. auris
and
S. aureus
in cancer cells demonstrated significantly higher IL‐6 and IL‐8 expression than
C. albicans
(p < 0.05). Furthermore, co‐culturing
C. auris
or
C. albicans
with
S. aureus
increases pro‐inflammatory IL‐8 expression in oral cancer cell lines compared to mono‐cultures of respective Candida.

Co‐culturing
C. auris
or
C. albicans
with
S. aureus
reduced cell viability and increased pro‐inflammatory IL‐8 expression in oral cancer cell lines, suggesting that interkingdom interaction may regulate oral carcinogenesis.