Liddle, Genevieve M.

A common feature of breast cancer cells is the
evasion of singular treatments by using the Warburg
Effect, a process of metabolic ATP production
through rapid anaerobic glycolysis. Cancer research
has transitioned to an investigation of combination
therapies to combat cancer. In our study, we seek
to metabolically inhibit cancer cells before application
of immunogenic killing. The Warburg Effect
was targeted with 3-Bromopyruvate (3-BP), which
blocks Glyceraldehyde 3-Phosphate Dehydrogenase
(GAPDH) production. Treatment with 3-BP yielded
up to 86.5% cancer cell death. Glycolytic inhibition
renders cancer cells metabolically stressed, which
may enable an effective immune response. Our
hypothesis was that CpG activated macrophage
will possess tumoricidal potential to target metabolically
stressed cancer cells. Macrophages and
CpG cultivation alone yielded a significant immune
response. We sought to find a synergistic effect of
3-BP induced killing susceptibility with CpG activated macrophages may lead to an effective method of
combination therapy.

Extracellular stimuli may influence the M1/M2 phenotypic polarization of
macrophages. We examined M1/M2 biomarkers, phagocytic activity, and tumoricidal
activity in RAW 264.7 mouse macrophages. Macrophages were treated with conditioned
media (CM) from 4T1 breast cancer cells, curcumin, 22-oxacalcitriol, LPS, or a
combination of the previously listed. Arginase activity, a M2 phenotypic biomarker, was
upregulated by the treatment of macrophages with conditioned media. Curcumin, 22-
oxacalcitriol, and LPS partially inhibited RAW 264.7 arginase activity in the presence of
4T1 breast cancer media. 22-oxacalcitriol increased the phagocytic ability of RAW 264.7
macrophages in the presence of M2 polarizing substances produced by the 4T1 breast
cancer cells. Also, LPS increased RAW 264.7 phagocytic ability in the presence of 4T1
breast cancer CM. This study looked at the potential substances that would possibly reverse the M2 tumor promoting macrophage phenotype seen in the breast cancer tumor
environment.