Colorectal cancer is the third most common cancer worldwide, making lymph node recovery critical for treatment decisions and prognosis. Within the colorectal tumor microenvironment, the metabolic programming of tumor-associated macrophages (TAMs) can drive both pro- and anti-tumor responses, yet the specific glycolytic pathways governing their pro-metastatic conversion present promising therapeutic targets. This study investigated the role of glycolysis activating enzyme 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) in mediating TAMs metabolic polarization, and its potential as a therapeutic target. PFKFB3 expression was found to be predominant in TAMs in CRC tumor samples. Lipidomic analysis performed by HPLC-MS/MS revealed that PFKFB3 inhibition altered glycerophospholipid metabolism (p = 6.13 × 10⁻¹⁰), and shifted TAMs toward sphingolipid-mediated immunosuppressive metabolism. PFKFB3 activity was associated with a specific reduction in asparagine availability, potentially pointing to a targeted reprogramming of amino acid metabolism supporting distinct TAM functions under conditions of intra-tumoral metabolic stress. These findings highlight PFKFB3 as an essential regulator of TAMs pro-tumoral metabolism in CRC, particularly in colon cancer.

Immunotherapy is a promising treatment strategy for treating colorectal cancer (CRC). Despite significant advances in this field, resistance and low efficacy of immunotherapy remain a principal problem. One of the most important factors affecting the response to immunotherapy is the tumor microenvironment (TME). Among the components of the TME, tumor-associated macrophages (TAMs) are key immune cells involved in cancer progression by stimulating tumor cell proliferation, angiogenesis, epithelial-mesenchymal transition, metastasis, and tumor immune evasion. This review presents currently investigated combination therapy based on the immune checkpoint inhibitors and inhibitors of diverse components of the TME, including TAMs, that can potentially increase the effectiveness of CRC treatment. Therapeutic efficacy, together with the functional activity of TAMs, is estimated in multiple preclinical data obtained with diverse in vitro and in vivo models. Ongoing clinical trials demonstrated the association of treatment effectiveness with TAM phenotypes and functions.

Introduction. Tumor-associated macrophages (TAMs) are essential innate immune cells in the tumor microenvironment. TAMs can stimulate cancer cell proliferation and primary tumor growth, angiogenesis, lymphangiogenesis, cancer cell invasiveness in vessels and metastatic niche formation as well as support chemotherapy resistance. TAMs are phenotypically diverse both in various cancer localizations and in intratumoral heterogeneous compartments. Tumor-specific modeling of TAMs is necessary to understand the fundamental mechanism of pro- and anti-tumor activity, to test their interaction with existing therapies, and to develop TAM- targeted immunotherapy. Aim of study: To investigate cancer-specific transcriptomic features of ex vivo human TAM models. Material and Methods. Here we compared transcriptomic profiles of TAMs for breast, colorectal, ovarian, lung, and prostate cancers ex vivo. Human monocytes were isolated from buffy coats, and then stimulated by the tumor cell conditioned medium ex vivo. Using real-time PCR, we quantified the expression of key TAM biomarkers including inflammatory cytokines, scavenger-receptors, angiogenesis-regulating genes, and matrix remodeling factors. Results. PCR analysis allowed revealing cancer-specific expression profiles of modeled TAMs. By comparing the existing knowledge about TAM phenotypes in human tumors in vivo with the collected data, we discuss the advantages and limitation of ex vivo TAM models derived from human blood monocytes. Conclusion. Monocytes-derived macrophages stimulated with cancer cell-conditioned medium can, to a certain extent, allow modeling of cancer-specific programming of TAMs. Our model system is valuable to examine agents reprogramming key TAM pro-tumoral activities, and for the reproducible analysis of mechanistic events that program tolerogenic status of TAMs towards cancer cells.

Colorectal cancer (CRC) is a prevalent malignancy with high incidence and mortality rates worldwide. Metabolic disorders, such as obesity, dyslipidemia, hyperglycemia, and hypertension, have been identified as significant risk factors contributing to the development and progression of CRC. These metabolic conditions often result in low-grade inflammation, which plays a crucial role in tumor initiation and progression. Monocytes, which differentiate into tumor-associated macrophages (TAMs) within the tumor microenvironment (TME), are pivotal in mediating these inflammatory responses. Monocytes in the individuals with metabolic disorders exhibit altered phenotypes and functions, enhancing their pro-inflammatory and tumor-promoting activities. Our review describes the intricate links between metabolic disorders and CRC on the level of circulating monocytes, highlighting how metabolic conditions can drive CRC initiation and aggravate tumor progression via programming of immunity. Various monocyte subsets, their phenotypic changes, and their impact on CRC are elucidated, providing insights into potential therapeutic targets for CRC prevention and treatment. Understanding the interplay between metabolic alterations and programming of monocytes-derived TAMs in the TME is essential for developing effective strategies against CRC.

Colorectal cancer is the third most common cancer worldwide, making lymph node re-covery critical for treatment decisions and prognosis. Within the colorectal tumor mi-croenvironment, the metabolic programming of tumor-associated macrophages (TAMs) can drive both pro- and anti-tumor responses, yet the specific glycolytic pathways gov-erning their pro-metastatic conversion present promising therapeutic targets. This study investigated the role of glycolysis activating enzyme 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) in mediating TAM metabolic polarization, and its potential as a therapeutic target. PFKFB3 expression was found to be predominant in tumor-associated macrophages in CRC human tumor sam-ples. Lipidomic analysis performed by HPLC-MS/MS revealed that PFKFB3 inhibition altered glycerophospholipid metabolism (p=6.13E-10), and shifted TAMs toward sphingolipid-mediated immunosuppressive metabolism. PFKFB3 activity was associated with a specific reduction in asparagine availability, potentially pointing to a targeted reprogramming of amino acid metabolism supporting distinct macrophage functions under conditions of intra-tumoral metabolic stress. These findings highlight PFKFB3 as an essential metabolic regulator of TAMs pro-tumoral activity in CRC, particularly in colon cancer.