Bladder cancer cells re-educate TAMs through lactate shuttling in the microfluidic cancer microenvironment

Abstract

BackgroundIn the present study, we aimed to investigate the influence of lactate shuttling on the functional polarization and spatial distribution of transitional cell carcinoma of the bladder (TCCB) cells and macrophages.MethodsWe designed a microfluidic coculture chip for real-time integrative assays. The effect of lactate shuttling on the re-education of macrophages by TCCB cells was explored by measuring the levels of NO using a total NO assay kit and by evaluating the protein expression of iNOS, p-NFkB-p65, Arg-1 and HIF-1α via cell immunofluorescence and western blotting. Additionally, we examined TCCB cell viability using acridine orange/ethidium bromide (AO/EB) and MitoTracker staining. Moreover, the concentration distributions of lactate and large signaling proteins in the culture chambers were measured using 4′,6-diamidino-2-phenylindole (DAPI) and fluorescein isothiocyanate-dextran (FITC-dextran). Furthermore, the recruitment of macrophages and the influence of macrophages on BC metastasis were observed via light microscopy.ResultsWe confirmed that TCCB cells reprogrammed macrophages into an M2 phenotype. Moreover, lactate inhibited M1 polarization and induced M2 polarization of macrophages, but blockade of cancer cell-macrophage lactate flux significantly inhibited the re-education of macrophages by TCCB cells. In addition, lactate diffused faster and deeper than large signaling proteins in the microfluidic tumor microenvironment. Furthermore, lactate alone induced the migration of macrophages, and M1, but not M2, macrophages reduced the motility of TCCB cells.ConclusionsTCCB cells reprogrammed macrophages into an M2 phenotype in a manner that depended on cancer cell-TAM lactate flux. Furthermore, the lactate shuttle may be a determinant of the density of TAMs in tumor tissue.

Intravesical treatment of chemotherapeutic agents sensitizes bacillus Calmette‑Guerin by the modulation of the tumor immune environment

“…In the tumor microenvironment, activated Th-1 produces immune-activating cytokines such as IL-2 and INF-γ, while stimulated CTLs play an important role in tumor immunity. Contrary to this, tumor cells produce immunosuppressive cytokines such as IL-10 and TNF-β and induce immunosuppressive cells such as TAMs, Tregs, and myeloid-derived suppressor cells (MDSCs) (26,(34)(35)(36). Various previous studies have suggested that intravesical chemotherapy modifies the tumor microenvironment into a less immunosuppressive condition, involving the induction of TAMs towards antitumoral M1 macrophages, proliferation of CTLs, an increase in the permeability of tumor cells to CTL-produced granzyme B, selective reduction of MDSCs, and recruitment of NK cells and CTLs expressing perforin, granzyme B, and IFN-γ (37)(38)(39)(40).…”

Functional TRAIL receptors in monocytes and tumor-associated macrophages: A possible targeting pathway in the tumor microenvironment

“…A number of different approaches has been used to target TAM in tumors: inhibition of their recruitment by using inhibitors of CCL2, alone or in combination therapy [9, 10]; the use of anti-CSF1R monoclonal antibodies or antagonists to the CSF1R tyrosine kinase [11–13]; as well as strategies aimed to their direct elimination, by inducing apoptosis or inhibition of vital pathways [14, 15], including inhibition of the mTOR pathway [16–18]. Finally a different approach is the re-programming of their functional phenotype to re-direct TAM towards cytotoxic effectors [19, 20]. Our group recently reported that trabectedin, a registered anti-tumor agent of marine origin, has interesting peculiar effects on the tumor micro-environment, in addition to block cell cycles in proliferating tumor cells.…”

Effect of isoflurane�+�N2O inhalation and propofol�+�fentanyl anesthesia on myocardial function as assessed by cardiac troponin, caspase‑3, cyclooxygenase‑2 and inducible nitric oxide synthase expression

“…Clinically, the judgment of anesthesia depth for patients is based on heart rate, blood pressure and body movement (14). However, the dose of propofol was decreased in anesthetic depth monitoring, which suggests that blood pressure and heart rate are inadequate for judging anesthesia depth, which may lead to excessive dosages of anesthetic drugs (6).…”