
LDH-A regulates the tumor microenvironment via HIF-signaling and modulates the immune response
Author(s) -
Inna Serganova,
Ilan Cohen,
Kiranmayi Vemuri,
Masahiro Shindo,
Masatomo Maeda,
Mayuresh Mane,
Е. А. Мороз,
Raya Khanin,
Jaya M. Satagopan,
Jason A. Koutcher,
Ronald G. Blasberg
Publication year - 2018
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0203965
Subject(s) - tumor microenvironment , bioluminescence imaging , cancer research , immune system , metastasis , gene knockdown , primary tumor , tumor progression , breast cancer , small hairpin rna , transfection , biology , medicine , cell culture , pathology , cancer , luciferase , immunology , genetics
Previous studies show that LDH-A knockdown reduces orthotopic 4T1 breast tumor lactate and delays tumor growth and the development of metastases in nude mice. Here, we report significant changes in the tumor microenvironment (TME) and a more robust anti-tumor response in immune competent BALB/c mice. 4T1 murine breast cancer cells were transfected with shRNA plasmids directed against LDH-A (KD) or a scrambled control plasmid (NC). Cells were also transduced with dual luciferase-based reporter systems to monitor HIF-1 activity and the development of metastases by bioluminescence imaging, using HRE-sensitive and constitutive promoters, respectively. The growth and metastatic profile of orthotopic 4T1 tumors developed from these cell lines were compared and a primary tumor resection model was studied to simulate the clinical management of breast cancer. Primary tumor growth, metastasis formation and TME phenotype were significantly different in LDH-A KD tumors compared with controls. In LDH-A KD cells, HIF-1 activity, hexokinase 1 and 2 expression and VEGF secretion were reduced. Differences in the TME included lower HIF-1α expression that correlated with lower vascularity and pimonidazole staining, higher infiltration of CD3 + and CD4 + T cells and less infiltration of TAMs. These changes resulted in a greater delay in metastases formation and 40% long-term survivors (>20 weeks) in the LDH-A KD cohort following surgical resection of the primary tumor. We show for the first time that LDH-depletion inhibits the formation of metastases and prolongs survival of mice through changes in tumor microenvironment that modulate the immune response. We attribute these effects to diminished HIF-1 activity, vascularization, necrosis formation and immune suppression in immune competent animals. Gene-expression analyses from four human breast cancer datasets are consistent with these results, and further demonstrate the link between glycolysis and immune suppression in breast cancer.