Fig. 4: KISS1R expression promotes primary breast tumor growth and glutamine metabolism in an orthotopic xenograft model.

Six-week-old immunocompromised mice were injected with SKBR3pFLAG controls (2 × 10⁶ cells/mouse) or SKBR3FLAG-KISS1R cells (10⁶ cells/mouse) into the mammary fat pad. a Primary tumor volume after 6 weeks for animals injected with SKBR3FLAG-KISS1R cells and 8 weeks for animals injected with SKBR3pFLAG controls. b Representative images of orthotopic primary tumors subjected to hematoxylin and eosin, antihuman cytochrome C oxidase, or antihuman glutaminase (GLS1); magnified section in white boxed area shown in image below. Metabolites in primary breast tumors (c, d) and serum (e, f), respectively, from xenografts: c, e glutamate and d, f glutamine levels measured by LC–MS. Student’s unpaired t test, *p < 0.05. (n = 4 mice for SKBR3FLAG-KISS1R xenografts; n = 3 for pFLAG control xenografts).