Streptococcus pneumoniae promotes lung cancer development and progression.

Area of Science:

• Microbiology
• Oncology
• Immunology

Background:

• Streptococcus pneumoniae (SP) is linked to lung cancer, but its role in tumorigenesis is unclear.
• Understanding microbial contributions to cancer is crucial for developing novel therapeutic strategies.

Purpose of the Study:

• To investigate the mechanism by which SP contributes to lung cancer development.
• To identify specific bacterial and host factors involved in SP-mediated tumorigenesis.

Main Methods:

• Investigated the interaction between SP and lung cancer cells using pneumococcal surface protein C (PspC) and platelet-activating factor receptor (PAFR).
• Assessed the impact of SP infection on cell proliferation and signaling pathways (PI3K/AKT, NF-kB) in vitro.
• Evaluated tumor formation and survival in a mouse model (BALB/C) with SP infection and/or carcinogen exposure.
• Utilized genetic mutations in PspC and PAFR to determine their role in SP-induced tumor promotion.

Main Results:

• SP binds to lung cancer cells through PspC-PAFR interaction, stimulating proliferation and activating PI3K/AKT and NF-kB pathways.
• SP infection led to larger tumors in mice and, combined with tobacco carcinogen, increased tumor incidence and reduced survival.
• Disruption of PspC or PAFR binding abrogated the tumor-promoting effects of SP.
• SP abundance correlated with patient survival.

Conclusions:

• SP plays a significant role in lung tumorigenesis by activating pro-cancerous signaling pathways via PspC-PAFR interaction.
• SP represents a potential microbial target for lung cancer diagnosis and therapeutic intervention.