The influence of Lactobacillus johnsonii on tumor growth and lymph node metastasis in papillary thyroid carcinoma

Abstract

The presence of lymph node metastasis (LNM) is one of the most crucial factors in the prognosis of papillary thyroid carcinoma (PTC). The aim of this study was to investigate the influence of intratumoral bacteria on the LNM in PTC. The intrathyroidal microbiome was analyzed in 55 PTC patients by 16S rRNA gene sequencing. The CCK8 and Transwell assays were conducted to determine the impact of bacteria on the proliferation and migration abilities of PTC cells. Xenograft tumor and bacterial colonization experiments were carried out using nude mice. We showed that Lactobacillus was significantly decreased in PTC lesions from patients with LNM. Lactobacillus johnsonii (L. johnsonii) could suppress the proliferation and migration capability of PTC cells in vitro and in vivo. Bacterial gut colonization of L. johnsonii increased its abundance in tumors and inhibited PTC growth and LNM. These findings suggested that L. johnsonii could be harnessed for the development of innovative therapeutic strategies for PTC.