find more TGF-β1 suppressed the acquisition by immature DCs of migratory capacity toward lymph nodes. Figure 5 Tumor-derived TGF-β1 suppresses migration of immature DCs from tumors to TDLNs. A, To assess migration of DCs from tumors to TDLNs, cultured bone-marrow dendritic cells (bmDCs) were labeled with CFSE and injected into the tumors. Shown are numbers of CFSE-labeled bmDCs within TDLNs counted by flow cytometry 24 h after injection. B, To clarify the maturation status of the migrated bmDCs, untreated immature CFSE-labeled bmDCs and LPS-treated mature CFSE-labeled bmDCs were injected. Note that the numbers of immature bmDCs migrating from TGF-β1-transfected tumors was lower than from mock-transfected tumors, whereas there was no significant difference between the numbers of migrated mature bmDCs. n = 10 in each group. LPS, lipopolysaccharide. Finally, to assess TDLN metastasis, we performed real time PCR JNJ-26481585 mouse analysis of AcGFP1 expression in TDLNs draining mock-and TGF-β1-transfected
tumors. By day 7 after implantation, metastasis was evident in TDLNs from 2 of 5 mice inoculated with TGF-β1 transfectant clone-1. By day 14, metastasis was detected 3 of 5 TDLNs from mice implanted with TGF-β1 transfectant clone-1 and in the same number of nodes from mice implanted with TGF-β1 transfectant clone-2. On the other hand, no metastasis was detected in TDLNs from mice implanted with mock-transfected clones (Figure 6A). Figure 6 Tumor derived TGF-β1 induced selleck inhibitor tumor metastasis in TDLNs. A, To evaluate tumor metastasis to TDLNs, expression of AcGFP1 mRNA within TDLNs was assessed by RT-PCR. B, Metastasis was confirmed by immunohistochemical
detection of CK19 and AcGFP1 within TDLNs draining TGF-β1-expressing tumors (left panel, clone 1; right panel, clone 2). C, Immunohistochemical detection of CK19 and AcGFP1 in TDLNs draining mock-transfected tumors. Note the absence of metastasis in TDLNs draining tumors not expressing TGF-β1. ADP ribosylation factor To confirm the metastasis, we immunohistochemically stained TDLNs with anti-AcGFP1 and anti-CK-19 antibodies. On day 14, AcGFP1+ and CK-19+ cell clusters were found in TDLNs from mice implanted with TGF-β1 transfectant clone-1 or clone-2 (Figure 6B). However, no AcGFP1+ or CK-19+ clusters were detected in TDLNs from mice implanted with a mock-transfectant clone (Figure 6C). Apparently, expression of TGF-β1 by tumor cells increases the likelihood of TDLN metastasis. Discussion In this report we demonstrated that overexpression of TGF-β1 by tumor cells increased the likelihood of metastasis to TDLNs. We also demonstrated that the overexpressed TGF-β1 inhibited DC migration from tumors into TDLNs. Together, these findings suggest that inhibition of DC migration toward TDLNs by tumor-derived TGF-β1 facilitates lymph node metastasis in TDLNs.