# Downregulation of carbonic anhydrase IX expression in mouse xenograft nasopharyngeal carcinoma model via doxorubicin nanobubble combined with ultrasound

## TL;DR

This study shows that combining doxorubicin nanobubbles with ultrasound can reduce carbonic anhydrase IX in a mouse model of nasopharyngeal cancer.

## Contribution

A novel combination of doxorubicin nanobubbles and ultrasound is shown to downregulate carbonic anhydrase IX in a mouse xenograft model of nasopharyngeal carcinoma.

## Key findings

- DOX-NB combined with DUS significantly increased doxorubicin release compared to DOX-NB alone.
- The DOX-NB + DUS group showed the lowest expression of CAIX and microvessel density in xenografted tumors.
- The combination therapy synergistically inhibited nasopharyngeal carcinoma cell activity.

## Abstract

The purpose of this study was to investigate whether doxorubicin nanobubbles (DOX-NB) combined with diagnostic ultrasound (DUS) irradiation could downregulate the expression of carbonic anhydrase IX (CAIX) in mouse xenograft nasopharyngeal carcinoma (NPC) model. In this study, the prepared DOX-NB was round and well dispersed. The average diameter of DOX-NB was 250.9 ± 50.8 nm, with an average polydispersity of 0.321 ± 0.05. The cumulative release of DOX in the DOX-NB + DUS group was significantly higher compared with that of the DOX-NB group (p < 0.05). DOX-NB combined with DUS irradiation could significantly inhibit cell viability (p < 0.05). The expression of CAIX and microvessel density (MVD) in the xenografted tumors was the lowest in the DOX-NB + DUS group compared with that of other groups (p < 0.05). In conclusion, DOX-NB combined with DUS irradiation could improve DOX-NB drug release and synergistically inhibit NPC cell activity. DOX-NB combined with DUS irradiation can downregulate the expression of CAIX in mouse xenograft NPC model. This may be due to the synergistic effect of DUS combined with DOX-NB in reducing MVD in NPC.