Modulation of Pulmonary Microbiota by Antibiotic or Probiotic Aerosol Therapy: A Strategy to Promote Immunosurveillance against Lung Metastases

The lung microbiota: role in maintaining pulmonary immune homeostasis and its implications in cancer development and therapy

“…Based on this evidence, we recently reported that the commensal lung microbiota can be in vivo manipulated by aerosolized antibiotics. This treatment, decreasing the percentage and activity of T regs and, at the same time, activating immune effector cells, enhanced immunosurveillance in the lung and reduced the growth of B16 melanoma lung metastases [68]. T regs reduction was associated with a decrease of abundance of the genus Streptococcus and the concomitant expansion of generally less represented genera of Proteobacteria and Actinobacteria [68].…”

Building upon current knowledge and techniques of indoor microbiology to construct the next era of theory into microorganisms, health, and the built environment

“…Colonization of the gut by L. johnsonii creates favorable conditions for co-colonization of the beneficial bacteria Bacillus fragilis by providing an N-glucan biosynthesis pathway, something which is reduced in the gut of asthmatics [79]. Oral probiotics are often effective in managing respiratory illness symptoms [80], and a small but encouraging amount of evidence exists on aerosolized or inhaled probiotics to similar effect [81,82]. Intranasal Lactobacillus paracasei reduced inflammation and immune system markers but increased neutropenia in the lungs of mice [81], and aerosolized Lactobacillus rhamnosus protected mice against transplanted lung tumors [82].…”

“…Oral probiotics are often effective in managing respiratory illness symptoms [80], and a small but encouraging amount of evidence exists on aerosolized or inhaled probiotics to similar effect [81,82]. Intranasal Lactobacillus paracasei reduced inflammation and immune system markers but increased neutropenia in the lungs of mice [81], and aerosolized Lactobacillus rhamnosus protected mice against transplanted lung tumors [82]. Importantly, successful probiotics for humans, in these and other studies, are comprised of lactic-acid bacterial species which are typically found on or near human mucosal surfaces at various body sites, but are not found in the built environment except when sourced from mammalian occupants.…”

Insights Into Lung Cancer Immune-Based Biology, Prevention, and Treatment

“…While most studies focused on the modulatory effects of the microbiome in response to immunotherapy, there have been some promising attempts to explore a potentially prominent relationship between the microbiome, immune system, and cancer in the preventive setting. In animal models, modulation of the lung microbiome using probiotics or antibiotics decreased tumor seeding in the lung and improved the effect of chemotherapy against experimental metastases (231). This was accompanied by antibiotic-or probiotic-mediated reduction of immunosuppressive cells in the lung and maturation of resident antigen presenting cells, respectively, (231).…”

“…In animal models, modulation of the lung microbiome using probiotics or antibiotics decreased tumor seeding in the lung and improved the effect of chemotherapy against experimental metastases (231). This was accompanied by antibiotic-or probiotic-mediated reduction of immunosuppressive cells in the lung and maturation of resident antigen presenting cells, respectively, (231). Fecal microbiome transplants from long-term pancreatic cancer survivors were also shown to modulate tumor immunosuppression and growth in mice, thereby providing rationale for microbiome interference to target ICB-refractory pancreatic tumors presumed to be poorly immunogenic (232).…”