Blockade of CCR1 induces a phenotypic shift in macrophages and triggers a favorable antilymphoma activity

CircRNA LOC729852 promotes bladder cancer progression by regulating macrophage polarization and recruitment via the miR-769-5p/IL-10 axis

Circular RNAs (circRNAs) function as tumour promoters or suppressors in bladder cancer (BLCA) by regulating genes involved in macrophage recruitment and polarization. However, the underlying mechanisms are largely unknown. The aim of this study was to determine the biological role of circLOC729852 in BLCA. CircLOC729852 was upregulated in BLCA tissues and correlated with increased proliferation, migration and epithelial mesenchymal transition (EMT) of BCLA cells. MiR-769-5p was identified as a target for circLOC729852, which can upregulate IL-10 expression by directly binding to and suppressing miR-769-5p. Furthermore, our results indicated that the circLOC729852/miR-769-5p/IL-10 axis modulates autophagy signalling in BLCA cells and promotes the recruitment and M2 polarization of TAMs by activating the JAK2/STAT3 signalling pathway. In addition, circLOC729852 also promoted the growth of BLCA xenografts and M2 macrophage infiltration in vivo. Thus, circLOC729852 functions as an oncogene in BLCA by inducing secretion of IL-10 by the M2 TAMs, which then facilitates tumour cell growth and migration. Taken together, circLOC729852 is a potential diagnostic biomarker and therapeutic target for BLCA.

Empowering macrophages: the cancer fighters within the tumour microenvironment in mantle cell lymphoma

In Mantle Cell Lymphoma (MCL), the role of macrophages within the tumour microenvironment (TME) has recently gained attention due to their impact on prognosis and response to therapy. Despite their low absolute number in MCL tumour tissue, recent findings reveal an association between the levels of macrophages and prognosis, consistent with trends observed in other lymphoma subtypes. M2-like macrophages, identified by markers such as CD163, contribute to angiogenesis and suppression of the immune response. Clinical trials with MCL patients treated with chemoimmunotherapy and targeted treatments underscore the adverse impact of high levels of M2-like macrophages. Immunomodulatory drugs like lenalidomide reduce the levels of MCL-associated CD163+ macrophages and enhance macrophage phagocytic activity. Similarly, clinical approaches targeting the CD47 "don't eat me" signalling, in combination with the anti-CD20-antibody rituximab, demonstrate increased macrophage activity and phagocytosis of MCL tumour cells. Cell-based therapies such as chimeric antigen receptor (CAR) T-cell have shown promise but various challenges persist, leading to a potential interest in CAR-macrophages (CAR-M). When macrophages are recruited to the TME, they offer advantages including phagocytic function and responsiveness to microenvironment alterations, suggesting their potential as a manipulable and inducible alternative when CAR T-cell therapies fails in the complex landscape of MCL treatment.

Chemokine receptor CCR1 regulates macrophage activation through mTORC1 signaling in nonalcoholic steatohepatitis

BACKGROUND AND AIMS

Chemokine (CC motif) receptor 1 (CCR1) promotes liver fibrosis in mice. However, its effects on nonalcoholic steatohepatitis (NASH) remain unclear. Therefore, the present study aimed to investigate the role of CCR1 in the progression of NASH.

METHODS

Human serum and liver tissues were obtained from patients with NASH and controls. Systemic (Ccr1-/-) and liver macrophage-knockout Ccr1 (Ccr1LKD) mice were fed a high-cholesterol and high-fat (CL) diet for 12 weeks or a methionine/choline-deficient (MCD) diet for 4 weeks. BX471 was used to pharmacologically inhibit CCR1 in CL-fed mice.

RESULTS

CCR1 was significantly upregulated in liver samples from patients with NASH and in animal models of dietary-induced NASH. In the livers of mice fed a CL diet for 12 weeks, the CCR1 protein colocalized with F4/80+ macrophages rather than with hepatic stellate cells. Compared to their wild-type littermates, Ccr1-/- mice fed with the CL or MCD diet showed inhibition of NASH-associated hepatic steatosis, inflammation, and fibrosis. Mechanistically, Ccr1 deficiency suppressed macrophage infiltration and activation by attenuating the mechanistic target of rapamycin complex 1 (mTORC1) signaling. Similar results were observed in Ccr1LKD mice administered the CL diet. Moreover, CCR1 inhibition by BX471 effectively suppressed NASH progression in CL-fed mice.

CONCLUSIONS

Ccr1 deficiency mitigated macrophage activity by inhibiting mTORC1 signaling, thereby preventing the development of NASH. Notably, the CCR1 inhibitor BX471 protected against NASH. These findings would help in developing novel strategies for the treatment of NASH.