Macrophages are needed in the progression of tuberculosis into lung cancer

Progress in mechanism-based diagnosis and treatment of tuberculosis comorbid with tumor

Tuberculosis (TB) and tumor, with similarities in immune response and pathogenesis, are diseases that are prone to produce autoimmune stress response to the host immune system. With a symbiotic relationship between the two, TB can facilitate the occurrence and development of tumors, while tumor causes TB reactivation. In this review, we systematically sorted out the incidence trends and influencing factors of TB and tumor, focusing on the potential pathogenesis of TB and tumor, to provide a pathway for the co-pathogenesis of TB comorbid with tumor (TCWT). Based on this, we summarized the latest progress in the diagnosis and treatment of TCWT, and provided ideas for further exploration of clinical trials and new drug development of TCWT.

Lung cancer occurrence after an episode of tuberculosis: a systematic review and meta-analysis

INTRODUCTION

People with tuberculosis experience long-term health effects beyond cure, including chronic respiratory diseases. We investigated whether tuberculosis is a risk factor for subsequent lung cancer.

METHODS

We searched PubMed, Scopus, Cochrane, Latin American and Caribbean Health Sciences Literature and the Scientific Electronic Library Online for cohort and case-control studies providing effect estimates for the association between tuberculosis and subsequent lung cancer. We pooled estimates through random-effects meta-analysis. The study was registered in PROSPERO (CDR42020178362).

RESULTS

Out of 6240 records, we included 29 cohort and 44 case-control studies. Pooled estimates adjusted for age and smoking (assessed quantitatively) were hazard ratio (HR) 1.51 (95% CI 1.30-1.76, I²=81%; five studies) and OR 1.74 (95% CI 1.42-2.13, I²=59%; 19 studies). The occurrence of lung cancer was increased for 2 years after tuberculosis diagnosis (HR 5.01, 95% CI 3.64-6.89; two studies), but decreased thereafter. Most studies were retrospective, had moderate to high risk of bias, and did not control for passive smoking, environmental exposure and socioeconomic status. Heterogeneity was high.

CONCLUSION

We document an association between tuberculosis and lung cancer occurrence, particularly in, but not limited to, the first 2 years after tuberculosis diagnosis. Some cancer cases may have been present at the time of tuberculosis diagnosis and therefore causality cannot be ascertained. Prospective studies controlling for key confounding factors are needed to identify which tuberculosis patients are at the highest risk, as well as cost-effective approaches to mitigate such risk.

CDllb+ targeted depletion of macrophages negatively affects bone fracture healing

Inflammation is an important part of the fracture repair process which requires osteogenic cells to interact with innate immune cells such as macrophages. All murine macrophages express the F4/80 cell surface marker but they may be further subdivided into two main phenotypes: M1 (proinflammatory) or M2 (anti-inflammatory) based on surface marker expression and function. Macrophages polarize between these two main classes in response to inflammation while differentially regulating the healing process. Studies have shown that F4/80+ cell ablation impairs fracture healing, however, the distinct phenotypes that participate in the early healing process is unclear. We hypothesized that the M1 subtype is essential for the early steps of fracture healing and their depletion would impair fracture repair. To test this hypothesis, M1 (F4/80+/MHCII+/CD86+/CDllb+) macrophages were depleted using a saporin conjugated Mac-1 antibody (Mac1SAP) in vitro using primary macrophages and in vivo using a mouse femur fracture model. Primary macrophages isolated from mice femoral bone marrow were either left undifferentiated (+PBS), differentiated into M1 macrophages (+LPS), or differentiated to M2 macrophages (+IL-4), and then treated with either vehicle or 10 pM Mac1SAP. Samples were collected at day 2 and 5 post Mac1SAP treatment. Macrophage subtypes were identified by flow cytometry and cytokine secretion profiles were quantified using xMAP. For the in vivo model, mice were treated with Mac1SAP 24 h prior to fracture. Femur bone marrow samples were collected and analyzed by flow cytometry, xMAP, immunohistochemistry, MicroCT, and histology. The results demonstrated that Mac1SAP significantly depleted M1 macrophages both in vivo and in vitro. Mac1SAP treatment altered expression of 75% of cytokines in vitro and 30% of cytokines in vivo including IL-6, TNF-a, and IP-10. In both the in vitro and in vivo models, the M1 subtype correlated highly with cytokines G-CSF, IL-1α, IL-6, IL-10, LIX, KC, MCP-1, IP-10, MIP1α, MIP1β, RANTES, IL-9, IL-2 and TNFα. M1 depletion was also found to reduced callus properties at day 14 via microCT analysis. Overall, the data suggests that depletion of M1 macrophages by Mac1SAP treatment alters the cytokine expression profiles during early bone repair which ultimately impairs bone healing.

Linking common non-coding RNAs of human lung cancer and M. tuberculosis

Lung cancer and pulmonary tuberculosis caused by Mycobacterium are two major causes of deaths worldwide. Tuberculosis linked lung cancer is known. However, the precise molecular mechanism of Mycobacterium associated increased risk of lung cancer is not understood. We report 45 common human miRNAs deregulated in both pulmonary tuberculosis and lung cancer. We show that sRNA_1096 and sRNA_1414 from M. tuberculosis have sequence homology with human mir-21. Hence, the potential role of these three small non-coding RNAs in rifampicin resistance in pulmonary tuberculosis is implied. Further, the linking of sRNA_1096 and sRNA_1414 from M. tuberculosis with the host lung tumorigenesis is inferred. Nonetheless, further analysis and validation is required to associate these three non-coding RNAs with Mycobacterium associated increased risk of lung cancer.