Table 1. Proposed GSL-glycan structures detected on the glycolipid membranes of ovarian cancer cells, IGROV1 (wildtype) and ∆B3GNT5 cells.

Type	No	Glycan Mass [M-H]-	Glycan Structures	PGC-ESI-QTOF-MS/MS		PGC-ESI-IT-MS/MS
				IGROV1	B3GNT5-edited IGROV1	P1-enriched IGROV1 (Anugraham M, et al, 2015)
Neutral GSL	1	505.2 (Pk)		6.34 ± 0.31	4.72 ± 2.38	0.00
	2	546.3		0.00	0.00	0.00
	3a	708.3 (Globo)		0.00	0.00	0.00
	3b	708.3 (Asialo-GM1)		0.00	0.00	0.00
	3c	708.3 (Neo-lacto)		4.52 ± 1.58	0.00	7.64
	4	870.3 (P1)		0.00	0.00	2.43
	5	911.3		1.25 ± 0.48	0.00	Trace
Sialylated GSL	6	634.2 (GM3)		14.18 ± 0.61	23.40 ± 4.32	12.86
	7	837.3 (GM2)		73.71 ± 2.40	71.88 ± 8.13	73.11
	8a	999.3 (GM1)		0.00	0.00	0.68
	8b	999.3 (α2-3 sialyl Paragloboside)		0.00	0.00	2.15
	8c	999.3 (LSTc)		0.00	0.00	1.14

Structures were assigned based on MS/MS fragmentation (where possible) and known biological GSL synthetic pathway constraints. All structures were depicted according to the CFG (Consortium of Functional Glycomics) notation with linkage placement. Specific linkages corresponding to Gal-GlcNAc (Type 1/Type 2) lactosamine linkages are also indicated (where possible). Values represent mean relative ion intensities ± s.d. of three replicates based on their extracted ion chromatograms (EIC). GSL-glycan structures derived from P₁-enriched IGROV1 cell line previously analyzed with PGC-ESI-IT-MS (20) are also shown for comparative profiling using two different MS platforms. Gb3 (Pk).

Glucose Galactose N-acetylglucosamine (GlcNAc) N-acetylgalactosamine (GalNAc) N-acetylneruaminic acid (NeuAc)