Gut metabolomics profiling of non-small cell lung cancer (NSCLC) patients under immunotherapy treatment

Abstract

Background: Despite the efficacy of immune checkpoint inhibitors (ICIs) only the 20-30% of treated patients present long term benefits. The metabolic changes occurring in the gut microbiota metabolome are herein proposed as a factor potentially influencing the response to immunotherapy.

Methods: The metabolomic profiling of gut microbiota was characterized in 11 patients affected by non-small cell lung cancer (NSCLC) treated with nivolumab in second-line treatment with anti-PD-1 nivolumab. The metabolomics analyses were performed by GC-MS/SPME and ¹H-NMR in order to detect volatile and non-volatile metabolites. Metabolomic data were processed by statistical profiling and chemometric analyses.

Results: Four out of 11 patients (36%) presented early progression, while the remaining 7 out of 11 (64%) presented disease progression after 12 months. 2-Pentanone (ketone) and tridecane (alkane) were significantly associated with early progression, and on the contrary short chain fatty acids (SCFAs) (i.e., propionate, butyrate), lysine and nicotinic acid were significantly associated with long-term beneficial effects.

Conclusions: Our preliminary data suggest a significant role of gut microbiota metabolic pathways in affecting response to immunotherapy. The metabolic approach could be a promising strategy to contribute to the personalized management of cancer patients by the identification of microbiota-linked "indicators" of early progressor and long responder patients.

Fig. 1

Principal component analysis (PCA) of integrated datasets of ¹H-NMR and GC–MS/SPME data at T₀. a PC score plot. b Loading plot. The first two components explained 47% of the total variance. In green and red circles are represented EP (early progressors, not responders) and LR (long responders) patients, respectively. a Red, early progressors (EPs); green, long responders (LRs). b 1: 1-butanol; 2: 1-hexanol; 3: 1-pentanol; 4: 2,6-dimethyl 4 heptanone; 5: 2-butanone; 6: 2-heptanone; 7: 2-hexanol; 8: 2-nonanone; 9: 2-octanol; 10: 2-octanone; 11: 2-pentanone; 12: 6-methyl-5-hepten-2-one; 13: benzaldehyde; 14: benzeneacetaldehyde; 15: cis-2,6-dimethyl-2,6-octadiene; 16: dimethyl disulfide; 17: dodecane; 18: indole; 19: methyl isobutyl ketone; 20: p-cresol; 21: tridecane; 22: Bile salt 1; 23: Bile salt 2; 24: U1; 25: 2-hydroxy-3-methylbutyric acid 26: U2; 27: valeric acid; 28: isovaleric acid; 29: leucine; 30: valine; 31: isoleucine; 32: U3; 33: 2-oxoisovaleric acid; 34: ethanol; 35: lactic acid; 36: acetoin; 37: 2-aminoisobutyrate; 38: alanine; 39: butyric acid; 40: lysine 41: acetic acid; 42: N-acetyl-moieties; 43: propionic acid; 44: glutamic acid; 45: succinic acid; 46: U4; 47: methionine; 48: aspartic acid; 49: trimethylamine (TMA); 50: 2-oxoglutarate; 51: malonic acid; 52: U5; 53: choline; 54: taurine; 55: methanol; 56: glycine; 57: b-arabinose; 58: b-galactose; 59: b-xylose; 60: b-glucose; 61: U6; 62: uracil; 63: orotic acid; 64: U7; 65: fumaric acid; 66: tyrosine; 67: phenylalanine; 68: U8; 69: formic acid; 70: nicotinic acid

Fig. 2

Concentration (µmol/g) of proprionic acid (median LR = 7.14 EP = 2.56), nicotinic acid (median LR = 0.08 EP = 0.04), lysine (median LR = 7.51 EP = 4.13), 2-pentanone (median LR = 0; EP = 53.9) tridecane (median LR = 0; EP = 11.03) and p-cresol (median LR = 582.91; EP = 1721.48)