Fig 2: Increased levels of inflammatory and myeloid cell growth factors in PDAC portal blood plasma.(A) Portal blood plasma from 11 patients collected immediately after PDAC tumor resection were analyzed in duplicate using Legendplex cytokine multiplex flow cytometric analysis. By this analysis, GM-CSF levels in PDAC patient portal blood plasma were found highly elevated compared to normal peripheral blood levels (depicted by red dotted line mean + SD, p = 0.0305). M-CSF levels were moderately elevated over normal levels (red line and dotted line depicts control mean + SD, p = 0.0383). Sample values are depicted as open circles, lines indicate mean of sample values with error bars showing standard error from the mean. (B) Portal blood plasma from 24 PDAC patients were analyzed for M-CSF, GM-CSF, and IL-34 by ELISA, indicating that the median levels of IL-34, IL-8, and GM-CSF in PDAC plasma (p = 0.0015, p = 0.0348, and p = 0.0020, respectively), were highly elevated in both PDAC portal (B) and peripheral (C) plasma compared to established levels seen in healthy peripheral blood plasma reported in the literature (healthy peripheral blood median depicted by red dotted lines). (C) Comparison of factor profiles in 19 matched PDAC patient portal (white bars) and peripheral (grey bars) plasma with adequate volume extended analysis showed significantly higher levels in portal blood of M-CSF (p = 0.0186), IL-6 (p = 0.0045), and IL-1ß (p = 0.0389), while levels of GM-CSF, IL-34, IL-8, IL-1a, and PGE2 were elevated in both portal and peripheral plasma. Interferon gamma (IFN?) was detectable only in peripheral blood plasma. Red lines indicate literature values for concentrations in non-malignant human plasma. The p values shown in black indicate where significant differences were found between PDAC portal and peripheral blood plasma samples of this study. The p values in red indicate where differences between portal or peripheral plasma samples were found significantly different from literature cited non-malignant control values. Error bars on all graphs indicate standard error from mean. * indicates p<0.05, ** p<0.01, and NS, no significant difference found (p>0.05).

Fig 3: Mechanism of action working model hypothesis: CTC influence on myeloid cell differentiation plays a pivotal role in CTC survival and T cell immune response.A) PDAC CTC draw portal blood myeloid cells to them via IL-8 chemotaxis receptor CXCR2 signaling and then manipulate their differentiation to MDSC and further to M-FB through their production of high levels of IL-34 and M-CSF. These suppressor cell populations promote T cell anergy through PD-1 and CTLA4 as well as give CTC growth factors, metabolic support, motility enhancement, and immune suppressive protection. B) When IL-8-CXCR2 and IL-34/M-CSF-CSF1R signaling are blocked, CTC are left without the support of MDSC and M-FB. This allows myeloid precursor cells and monocytes in the portal blood to differentiate away from CTC influence, allowing them to respond to their own and other immune cell signaling for development into activated antigen presenting cells (APC) including inflammatory activated macrophages, and dendritic cells, instead of MDSC. Myeloid APC can then go on to re-activate anergized memory T cells to re-gain their anti-tumor cytotoxic potential and promotes CTC apoptosis. Anti-tumor macrophages and disruption of CTC-M-FB cluster formation can also directly affect CTC proliferation, mobilization, and apoptosis, thus hindering their survival in the portal blood and preventing their metastatic progression.

Fig 4: The involvement of CSF1R/JAK3/STAT6 activation and IL-34 autocrine production are responsible for the increases in proliferation, migration and invasion of eutopic ESCs in endometriosis. Eutopic ESCs were isolated from five individuals and three replicates were taken for each experiment. Representative results are shown. (A) Western blot showing the screening of related proteins that respond to recombinant IL-34 stimulation. Three independent experiments were performed and representative images are shown. (B–F) Eutopic ESCs were pre-treated with 100 nM AS1517499 for 30 min and then treated with or without IL-34 (100 ng/mL). Cell proliferation (B) detected by CCK-8. Cell migration (C) and invasion (D) detected by transwell assays. Scale bar: 100 µm. The protein levels of several mediators (E) as detected by western blot. Three independent experiments were performed and representative images are shown. The transcriptional levels of several mediators (F) as detected by qRT-PCR. (G) Eutopic ESCs were treated with STAT6 siRNA (siSTAT6#1)/control siRNA (siNC) in the presence of IL-34 (100 ng/mL). The transcriptional levels of several mediators as detected by qRT-PCR. (H) After transfection with si-STAT6 or pcDNA3.1-STAT6, a ChIP assay was used to detect the binding of STAT6 to the IL-34 promoter in ESCs. Immunoprecipitation was performed using anti-STAT6 antibody. Rabbit IgG was used as a negative control. ns: no statistical difference, *P < 0.05, **P < 0.01, ***P < 0.001.

Fig 5: Correlation between M-CSF/IL-34 expression with poor survival in lung cancer patients. (a) Kaplan-Meier analysis showing overall survival in lung cancer patients that show M-CSFWeak/Absent/IL-34Weak/absent expression compared to M-CSFWeak/Absent/IL-34High group. (b) Kaplan-Meier analysis of overall survival in lung cancer patients that show M-CSFWeak/Absent/IL-34Weak/absent expression compared to M-CSFHigh/IL-34High group. (c) Kaplan-Meier analysis of overall survival in lung cancer patients that show M-CSFWeak/Absent/IL-34Weak/absent expression compared to M-CSFHigh/IL-34High group.