Macrophages, as a Promising Strategy to Targeted Treatment for Colorectal Cancer Metastasis in Tumor Immune Microenvironment

Abstract

The tumor immune microenvironment plays a vital role in the metastasis of colorectal cancer. As one of the most important immune cells, macrophages act as phagocytes, patrol the surroundings of tissues, and remove invading pathogens and cell debris to maintain tissue homeostasis. Significantly, macrophages have a characteristic of high plasticity and can be classified into different subtypes according to the different functions, which can undergo reciprocal phenotypic switching induced by different types of molecules and signaling pathways. Macrophages regulate the development and metastatic potential of colorectal cancer by changing the tumor immune microenvironment. In tumor tissues, the tumor-associated macrophages usually play a tumor-promoting role in the tumor immune microenvironment, and they are also associated with poor prognosis. This paper reviews the mechanisms and stimulating factors of macrophages in the process of colorectal cancer metastasis and intends to indicate that targeting macrophages may be a promising strategy in colorectal cancer treatment.

CMTM3 as a Potential New Immune Checkpoint Regulator

“…It has also been reported that CALD1, a key gene associated with cancer-associated fibroblasts, can promote the progression of bladder cancer by remodeling the tumor microenvironment [ 24 ]. By modifying the tumor immune milieu, macrophages regulate malignant capabilities of colorectal cancer, according to Zhang et al [ 25 ].…”

Interaction Between Macrophage Extracellular Traps and Colon Cancer Cells Promotes Colon Cancer Invasion and Correlates With Unfavorable Prognosis

“…Some studies showed that high macrophage infiltration along the tumor front brings a high survival advantage for patients with CRC ( 38 ). However, more studies demonstrate that TAM promotes the growth and development of tumors ( 39 , 40 ). These findings suggest that there may be other factors that function in the crosstalk of macrophages and colon cancer cells.…”

Nanozyme-laden intelligent macrophage EXPRESS amplifying cancer photothermal-starvation therapy by responsive stimulation

“…Targeted delivery with imaging navigation is an effective strategy for precise tumor delivery that we have recently developed [ 15 , 16 ]. Macrophage-based drug delivery system has attracted intensive attention for its unique characterizations as biocompatibility, phagocytic property, vessel migration and tumor infiltration [ [17] , [18] , [19] ]. Attributed to the inherent tumor tropism, macrophage-based delivery system could naturally target therapeutic drugs to tumor site [ 19 , 20 ].…”

“…Macrophage-based drug delivery system has attracted intensive attention for its unique characterizations as biocompatibility, phagocytic property, vessel migration and tumor infiltration [ [17] , [18] , [19] ]. Attributed to the inherent tumor tropism, macrophage-based delivery system could naturally target therapeutic drugs to tumor site [ 19 , 20 ]. Previous studies have reported a series of macrophage delivery systems engulfed Dox, nanozymes or liposomes, which appeared good therapeutic effects by targeted delivery [ 21 , 22 ].…”