BSG Products To Assist in Analyzing Macrophage Polarization

Background

Challenge

Solution

As represented by these citations, Cleanascite™, our lipid removal product, is especially suited to study macrophage polarization in vitro.


Zhang, T., Zhao, F., Hu, Y. et al. Environmental monobutyl phthalate exposure promotes liver cancer via reprogrammed cholesterol metabolism and activation of the IRE1α-XBP1s pathway. Oncogene (2024). https://doi.org/10.1038/s41388-024-03086-1

Humans are widely exposed to phthalates, a major chemical plasticizer that accumulates in the liver. However, little is known about the impact of chronic phthalate exposure on liver cancer development. In this study, we applied a long-term cell culture model by treating the liver cancer cell HepG2 and normal hepatocyte L02 to environmental dosage of monobutyl phthalate (MBP), the main metabolite of phthalates. MBP exposure triggered the reprogramming of lipid metabolism, which contributed to an immunosuppressive tumor microenvironment (TME). Abnormalities in lipid metabolism is a molecular hallmark for not only cancer cells, but also tumor-associated immune cells.

To study those abnormalities, the article states “To investigate the role of lipids in regulating the macrophage function, we first employed Cleanascite to remove all lipids and lipoproteins from the conditioned media (CM) of HepG2 cells. Interestingly, lipid-depleted HepG2 CM significantly suppressed the migration ability of THP-1PMA cells both in control and MBP-exposed groups (Fig. D). Also, the expression of M2-type markers (such as CD206, CD163, and ARG1) in THP-1PMA cells dramatically decreased after lipid clearance, while the expression of M1-type markers (such as iNOS, CD80, and CD86) was up-regulated.”.

Figure S8. MBP-induced tumor cell cholesterol accumulation promotes macrophage infiltration and M2-polarization

N(D) Detection of THP-1PMA cell migration ability affected by conditioned medium (CM) from P30 HepG2MBP and HepG2Veh cells treated with or without Cleanascite (n = 3). Scale bar, 50 μm.

The authors conclude that MBP induced cholesterol accumulation in HepG2 cells, facilitated M2 polarization of macrophages, thereby contributing to an immunosuppressive Tumor microenvironment (TME) that further favored cancer development.
Chan, David, et al. "Polyunsaturated Fatty Acids Promote Protumoral Macrophage Polarization via a RhoA-YAP1 Signaling Pathway in the Ovarian Cancer Microenvironment." (2022).



Tumor-associated macrophages (TAMs) are crucially associated with tumor development and progression; however, it remains unclear how the tumor microenvironment (TME) rewires the metabolic circuits and preferentially induces TAMs to polarize toward a protumoral phenotype. This study reports that polyunsaturated fatty acids (PUFAs) in malignant ascites promote protumoral M2-like TAMs deposition and facilitate peritoneal metastases of epithelial ovarian cancer (EOC). The article states “To selectively remove lipids, Cleanascite™ Lipid Removal Reagent (Biotech Support Group) was added to the omental conditioned medium (OCM) according to the manufacturer’s suggestions. … Intriguingly, the removal of free fatty acids in OCM by the Cleanascite™ attenuated lipid droplets deposition in M2-like MΦs and OCM-MΦs (Fig. 4A), indicating protumoral M2-like TAMs exhibited higher lipid accumulation and metabolism in the fatty acid-enriched OCM or the malignant ascites.”

“… Similarly, we demonstrated that the cellular ROS levels in OCM/AS-MΦs derived from PBMC MΦs were significantly upregulated, whereas the addition of Cleanascite™ mitigated the increased malignant ascites microenvironment (MAM)-mediated ROS level, indicating that the accumulation of UFAs in the MAM is responsible for the enhanced ROS production in TAMs (Fig. 4C). … Here, we further found …removal of lipids by Cleanascite™ remarkably prevented the reduction of YAP1 in OCM-MΦs, implying that the lipids within MAM facilitates protumoral M2-like TAMs polarization through the regulation of RhoA-YAP1 signaling cascade.” The article concludes that PUFAs are a key player in promoting tumor-infiltrated TAMs polarization that, in turn, facilitates EOC tumor growth and metastasis.



Di Conza, Giusy, et al. "Tumor-induced reshuffling of lipid composition on the endoplasmic reticulum membrane sustains macrophage survival and pro-tumorigenic activity." Nature immunology (2021): 1-13. Tumor-associated macrophages (TAMs) display pro-tumorigenic phenotypes for supporting tumor progression in response to microenvironmental cues imposed by tumor and stromal cells. However, the underlying mechanisms by which tumor cells instruct TAM behavior remain elusive. The investigators here uncover that tumor-cell-derived glucosylceramide stimulated unconventional endoplasmic reticulum (ER) stress responses by inducing reshuffling of lipid composition and saturation on the ER membrane in macrophages.
As part of the study, a comparison of culture media (CM) with and without lipids was made. The article states “To generate culture media without lipids, …CM was treated with Cleanascite according to the manufacturer’s instructions.”. The authors uncover the unexpected roles of tumor-cell-produced lipids that simultaneously orchestrate macrophage polarization and survival in tumors via induction of ER stress responses and reveal therapeutic targets for sustaining host antitumor immunity.

For removal of Hemoglobin interference, the following citation is provide.