Tumour-associated macrophages (TAMs), encompassing M1 and M2 subtypes, exert significant effects on osteosarcoma (OS) progression and immunosuppression. However, the impacts of TAM-derived biomarkers on the progression of OS remains limited. The GSE162454 profile was subjected to single-cell RNA (scRNA) sequencing analysis to identify crucial mediators between TAMs and OS cells. The clinical features, effects and mechanisms of these mediators on OS cells and tumour microenvironment were evaluated via biological function experiments and molecular biology experiments. Phosphodiesterase 4C (PDE4C) was identified as a pivotal mediator in the communication between M2 macrophages and OS cells. Elevated levels of PDE4C were detected in OS tissues, concomitant with M2 macrophage level, unfavourable prognosis and metastasis. The expression of PDE4C was observed to increase during the conversion process of THP-1 cells to M2 macrophages, which transferred the PDE4C mRNA to OS cells through exosome approach. PDE4C increased OS cell proliferation and mobility via upregulating the expression of collagens. Furthermore, a positive correlation was observed between elevated levels of PDE4C and increased TIDE score, decreased response rate following immune checkpoint therapy, reduced TMB and diminished PDL1 expression. Collectively, PDE4C derived from M2 macrophages has the potential to enhance the proliferation and mobility of OS cells by augmenting collagen expression. PDE4C may serve as a valuable biomarker for prognosticating patient outcomes and response rates following immunotherapy.

Cigarette smoke initiates an inflammatory response that has aftermath long after quitting. We segregated former smokers, according to their lung function and their co-founding diseases, in 3 groups: Cancer, Emphysema and COPD. Then we searched for outlier genes in intersections of Venn diagrams where we identified 6 subsets and 23 genes that may be responsible for disease outcome. Genes expressed in the cancer patients with or without emphysema (PPA subset) were BHLH, FPRL2, CD49D, DEADH, NRs4A3, MBLL, GNS, BE675435, ISGF-3, and FLJ23462. Patients with emphysema as co-founding disease, with or without cancer (APP), had only ANXA2 in common. Genes expressed only in non-cancer patients (AAP subset) of COPD group were IL-1A, SOX13, RPP38; TBXA2R, NPEPL1, CFLAR, TFEB, PRKCBP1, IGF1R, DDX11, and KCNAB1. HIV-1Rev was the gene expressed in cancer patients with emphysema (APA subset). Then, we also looked at out-layers genes significantly expressed in all patients (PPP subset with 5066 genes), the down-regulated in Emphysema were MMP9, PLUNC, CEACAM5, and NR4A1 while the up-regulated were F2R, COL15A1, PDE4C, and BGN. We chose genes and checked them at the protein level on immune cells, this showed that neutrophils from Cancer group had increased expression of CD49d, and their total number was also increased in bronchial-alveolar lavage (154%). Macrophages in the lung of patients with emphysema were associated with a significant increase of adhesion molecule CD58 and to significant CD95 decrease, indicating they do not die. Besides, macrophages downregulated MMP9 in the lung compared to blood macrophages. Overall, we find that cancer progression requires a stickier and greater number of neutrophils in the lung while emphysema requires stickier and longevous macrophages to lead matrix destruction, and together with higher expression of SOX13 and RPP38, may promote autoimmunity. We also identified two genes, ANXA2 and HIV1-rev, that may be a pivot between cancer and emphysema outcome of inflammation.

DNA-methylation (DNAm) levels at age-associated CpG sites can be combined into epigenetic aging signatures to estimate donor age. It has been demonstrated that the difference between such epigenetic age-predictions and chronological age is indicative for of all-cause mortality in later life. In this study, we tested alternative epigenetic signatures and followed the hypothesis that even individual age-associated CpG sites might be indicative for life-expectancy. Using a 99-CpG aging model, a five-year higher age-prediction was associated with 11% greater mortality risk in DNAm profiles of the Lothian Birth Cohort 1921 study. However, models based on three CpGs, or even individual CpGs, generally revealed very high offsets in age-predictions if applied to independent microarray datasets. On the other hand, we demonstrate that DNAm levels at several individual age-associated CpGs seem to be associated with life expectancy - e.g., at CpGs associated with the genesPDE4C and CLCN6. Our results support the notion that small aging signatures should rather be analysed by more quantitative methods, such as site-specific pyrosequencing, as the precision of age-predictions is rather low on independent microarray datasets. Nevertheless, the results hold the perspective that simple epigenetic biomarkers, based on few or individual age-associated CpGs, could assist the estimation of biological age.