Tumor‐derived tumor necrosis factor‐alpha promotes progression and epithelial‐mesenchymal transition in renal cell carcinoma cells

Abstract

Pro-inflammatory cytokines and chemokines are involved in promoting tumorigenesis by facilitating tumor proliferation and metastasis. The serum levels of interleukin (IL)-6, IL-1β β β β, and tumor necrosis factor-alpha (TNF-α α α α) are significantly elevated in patients with renal cell carcinoma (RCC). However, the mechanisms of how these cytokines participate in the progression of RCC remains unknown. In the present study, we investigated the effects of tumorderived cytokines on invasion and the epithelial-mesenchymal transition (EMT) of RCC cells. We found that expression of IL-1β β β β, IL-6, TNF-α α α α, hypoxia-inducible factor-alpha (HIF-1α α α α), and matrix metalloproteinase-2 (MMP2) were significantly elevated in high malignancy A498 (1) Four types of RCC have been delineated clinically and the genes responsible for them have been characterized. Overall, 75% of RCC are the clear cell type (ccRCC), while the other 25% are made up of the papillary, chromophobe, and oncocytic types. (2) Defects in the von Hippel-Lindau (VHL) gene appear to be responsible for 60% of sporadic ccRCC. A quarter of patients present with locally invasive or metastatic RCC. A third of the patients after resection of the tumor will have a recurrence. Moreover, systemic theraputic treatments of advanced RCC are largely ineffective and do not improve patient survival.(1,2) Therefore, defining the factors involved in disease progression and metastasis will provide molecular targets for the development of effective therapies.A complex network of pro-inflammatory cytokines, chemokines, and their receptors influences the development of primary tumors and metastasis. (3,4) CXCR4 is most commonly found in malignant cells from different cancer types.(4) In addition to CXCR4, CCR3 has been found to be up-regulated in 28% RCC tissues and correlates with a higher grade of malignancy.(5) Furthermore, the levels of IL-6, IL-1β, and TNF-α in serum are significantly higher and correlated with tumor size in RCC.(6) IL-6 blood level is significantly higher in patients with lymph node invasion and distant metastases, while TNF-α level is significantly higher as the stage of the RCC increases.(6,7) Therefore, IL-6 may be one of the factors associated with poor prognosis of patients with RCC. In addition, TNF-α may be useful as marker for the early diagnosis of RCC.(6) However, little is known about how these cytokines affect RCC migration and progression.The epithelial-mesenchymal transition (EMT) is a process in which polarized epithelial cells are converted into motile mesenchymal cells. Alterations in adhesion, morphology, cellular architecture, and migration capacity are the major events that occur during this process.(8) Common molecular markers for the EMT include increased expression of vimentin, nuclear localization of β-catenin, and increased production of transcriptional factors that inhibit E-cadherin production. Phenotypic markers for EMT comprise an increased capacity for migration and three-dimensional invasion as well as resistance t...

TNF-α Induces Epithelial–Mesenchymal Transition of Renal Cell Carcinoma Cells via a GSK3β-Dependent Mechanism

“…These growth factors derived from RCC may be responsible for the constitutive activation of Akt. In addition, TNF-a is also secreted by tumor-associated inflammatory cells and RCC (17). TNF-a stimulated activation of PI3K/Akt and further enhanced tumor progression in RCC.…”

“…TNF-a, a major mediator of cancer-related inflammation, can induce generation of different types of mediators, including reactive oxygen intermediates, cyclooxygenase, MMPs, and cytokines (6). RCC cells with mutated von Hippel-Lindau (VHL) and high malignant potential (2, 3) were found to produce increased low-level of TNF-a secretion ($10 pg/mL cells) (5,17,23). Coexpression of TNF-a and its receptors in RCC cells results in autocrine-and/or paracrine-stimulated growth (8,21).…”

“…Culture supernatants were collected and concentrated with Vivaspin 6 centrifugal concentrators (Vivascience). Concentrated supernatants (20 mg) were loaded for electrophoresis under nonreducing conditions on 10% SDS-polyacrylamide gels containing 1 mg/mL gelatin, as previously described (17). After electrophoresis, the gels were washed in 2.5% Triton X-100 and then incubated for 20 to 22 hours at 37 C in the development buffer containing 0.01 mol/L CaCl 2 and 0.05 mol/L TrisHCl (pH 8.0).…”

Hypertension and Circulating Cytokines and Angiogenic Factors in Patients With Advanced Non-Clear Cell Renal Cell Carcinoma Treated With Sunitinib: Results From a Phase II Trial

“…An extensive array of early reports indicated that TNF had oncolytic and antiproliferative effects in RCC [17][18][19]. However, later studies have cast this cytokine, which is secreted by immune and tumor cells, as an immunosuppressive mediator that promotes RCC progression [20][21][22]. TNF has thus been reported to kill T cells isolated from patients with metastatic RCC but not T cells from healthy donors and to inhibit CD81 T cells through the induction of programmed death ligand 1 on RCC cells [23,24].…”

TNFR1 mediates TNF-α-induced tumour lymphangiogenesis and metastasis by modulating VEGF-C-VEGFR3 signalling

“…TNF-a exhibits potent pro-angiogenic activity and stimulates tumour angiogenesis 40 , which is essential for tumour growth and invasion. TNF-a induces EMT transition in epithelial carcinomas and thus promotes tumour invasion 41 , and promotes tumour invasion by activation of MMPs such as MMP9 (ref. 42).…”