Doxycycline Attenuates Cancer Cell Growth by Suppressing NLRP3-Mediated Inflammation

Abstract

NLR family pyrin domain containing 3 (NLRP3) inflammasome formation is triggered by the damaged mitochondria releasing reactive oxygen species. Doxycycline was shown to regulate inflammation; however, its effect on NLRP3 in cancer remains largely unknown. Therefore, we sought to determine the effect of doxycycline on NLRP3 regulation in cancer using an in vitro model. NLRP3 was activated in a prostate cancer cell line (PC3) and a lung cancer cell line (A549) before treatment with doxycycline. Inflammasome activation was assessed by analyzing RNA expression of NLRP3, Pro-CASP-1, and Pro-IL1β using RT-qPCR. Additionally, NLPR3 protein expression and IL-1β secretion were analyzed using Western blot and ELISA, respectively. Tumor cell viability was determined using Annexin V staining and a cell proliferation assay. Cytokine secretion was analyzed using a 41Plex assay for human cytokines. Data were analyzed using one-way ANOVA model with Tukey’s post hoc tests. Doxycycline treatment decreased NLRP3 formation in PC3 and A549 cells compared to untreated and LPS only treated cells (p < 0.05). Doxycycline also decreased proliferation and caused cell death through apoptosis, a response that differed to the LPS-Nigericin mediated pyroptosis. Our findings suggest that doxycycline inhibits LPS priming of NLRP3 and reduces tumor progression through early apoptosis in cancer.

Azithromycin and Ceftriaxone Differentially Activate NLRP3 in LPS Primed Cancer Cells

“…Therefore, in this study, A549 and PC3 cells were treated with LPS (1 µg/mL; 3 h) to induce NLRP3 and pro-IL-1 β RNA synthesis. Ng (20 µm) was added to initiate inflammasome activation and assembly [ 18 , 19 ]. Antibiotics Az (150 µm) and Cf (100 µg/mL) were added 3 h post LPS treatment.…”

“…Our previous data indicate that some antibiotics, such as nigericin, activate the inflammasome, support inflammation, and have a pro-tumorigenic effect [ 18 ]. In contrast, other antibiotics, such as doxycycline, could oppose inflammasome activation and have an inhibitory effect on cancer cell growth [ 19 ]. Therefore, our data emphasize the importance of testing the effect of antibiotics on inflammasome activation to avoid selection of antimicrobial agent supporting inflammation and tumor progression when used to treat cancer patients.…”

“…Some antibiotics have the potential to affect NLRP3 activation by targeting host cell mitochondria [ 19 , 30 ]. Mitochondria are the primary source of cellular reactive oxygen species (ROS) [ 31 ] which promote NLRP3 activation [ 32 ].…”

Perspectives on the mechanism of pyroptosis after intracerebral hemorrhage

“…Toll-like receptors (TLR) and C-type lectin receptors (CLR) are transmembrane receptors, while retinoic acid-inducible gene (RIG) I-like receptors (RLR) and NOD-like receptors are cytosolic receptors (NLR) ( 14 – 16 ). Currently, the most widely studied inflammasome is the NOD-like receptor protein 3 (NLRP3) inflammasome, which has been shown to mediate the appearance of pyroptosis in a variety of diseases, including dilated cardiomyopathy, ischemic stroke, myocardial ischemia, ICH, inflammation and neoplastic diseases ( 17 – 24 ).…”

Classification of pyroptosis patterns and construction of a novel prognostic model for prostate cancer based on bulk and single-cell RNA sequencing

“…Another study found that PD-L1 induced pyroptosis in breast cancer, resulting an immune microenvironment unfavorable for tumor growth ( 20 ). In the last few years, several drugs and compounds and inorganic selenium have been proven to induce pyroptosis in PCa cells and have antitumor potential ( 21 – 23 ). These findings indicate that pyroptosis may be a potential therapeutic target for PCa patients.…”