Von Hippel-Lindau regulates interleukin-32β stability in ovarian cancer cells

A Critical Overview of Interleukin 32 in Leishmaniases

Interleukin-32 (IL-32) has several immune regulatory properties, which have driven its investigation in the context of various diseases. IL-32 expression is reported to be induced in the lesions of patients with American tegumentary leishmaniasis (ATL) by the New World Leishmania spp. that are responsible for causing ATL and visceral leishmaniasis (VL). IL-32 expression may elevate the inflammatory process through the induction of pro-inflammatory cytokines and also via mechanisms directed to kill the parasites. The genetic variants of IL-32 might be associated with the resistance or susceptibility to ATL, while different isoforms of IL-32 could be associated with distinct T helper lymphocyte profiles. IL-32 also determines the transcriptional profile in the bone marrow progenitor cells to mediate the trained immunity induced by β-glucan and BCG, thereby contributing to the resistance against Leishmania. IL-32γ is essential for the vitamin D-dependent microbicidal pathway for parasite control. In this context, the present review report briefly discusses the data retrieved from the studies conducted on IL-32 in leishmaniasis in humans and mice to highlight the current challenges to understanding the role of IL-32 in leishmaniasis.

Ultrasound Microbubble-Mediated VHL Regulates the Biological Behavior of Ovarian Cancer Cells

According to the literature, the von Hippel-Lindau (VHL) gene has a certain correlation with ovarian cancer. In this study, we investigated the effect and mechanism of ultrasound microbubble-mediated VHL on the biological function of ovarian cancer cells. Non-targeting lipid microbubbles and targeted lipid microbubbles were prepared. OVCAR-3 cells were treated with VHL mediated by ultrasound and microbubbles alone or together. Expressions of VHL, Akt, epithelial-mesenchymal-transition-related proteins and apoptosis-related proteins were detected by Western blot and quantitative real-time polymerase chain reaction as needed. The effect of ultrasound microbubble-mediated VHL on the proliferation, apoptosis, cell cycle, migration and invasion of OVCAR-3 cells was examined by Cell Counting Kit-8, flow cytometry, wound-healing assay and Transwell. Compared with other treatment methods, ultrasound microbubble mediation enhanced VHL expression in OVCAR-3 cells. Overexpression of liposome-mediated VHL inhibited the proliferation and migration; caused cell-cycle arrest; promoted apoptosis: downregulated the expressions of MMP2, MMP9, E-cadherin, Akt and Bcl-2; and upregulated the expressions of VHL and BCL2-associated X protein (BAX) in OVCAR-3 cells. The effect of microbubble-treated VHL was similar to liposome-mediated regulation, while ultrasound treatment enhanced the effect of VHL on OVCAR-3 cells. More interestingly, ultrasound microbubble-mediated VHL had the most obvious regulatory effect on OVCAR-3 cells. Ultrasound microbubble technology increases the transfection efficiency of VHL into OVCAR-3 cells and enhances the effect of VHL gene on the biological function of OVCAR-3 cells.

Molecular interactions and functions of IL-32

IL-32 is a multifaceted cytokine associated with several diseases and inflammatory conditions. Its expression is induced in response to cellular stress such as hypoxia, infections, and pro-inflammatory cytokines. IL-32 can be secreted from cells and can induce the production of pro-inflammatory cytokines from several cell types but are also described to have anti-inflammatory functions. The intracellular form of IL-32 is shown to play an important role in various cellular processes, including the defense against intracellular bacteria and viruses and in modulation of cell metabolism. In this review, we discuss current literature on molecular interactions of IL-32 with other proteins. We also review data on the role of intracellular IL-32 as a metabolic regulator and its role in antimicrobial host defense.

Interleukin-32: Frenemy in cancer?

Interleukin-32 (IL-32) was originally identified in natural killer (NK) cells activated by IL-2 in 1992. Thus, it was named NK cell transcript 4 (NK4) because of its unknown function at that time. The function of IL-32 has been elucidated over the last decade. IL-32 is primarily considered to be a booster of inflammatory reactions because it is induced by pro-inflammatory cytokines and stimulates the production of those cytokines and vice versa. Therefore, many studies have been devoted to studying the roles of IL-32 in inflammation-associated cancers, including gastric, colon cancer, and hepatocellular carcinoma. At the same time, roles of IL-32 have also been discovered in other cancers. Collectively, IL-32 fosters the tumor progression by nuclear factor-κB (NF-κB)-mediated cytokines and metalloproteinase production, as well as stimulation of differentiation into immunosuppressive cell types in some cancer types. However, it is also able to induce tumor cell apoptosis and enhance NK and cytotoxic T cell sensitivity in other cancer types. In this review, we will address the function of each IL-32 isoform in different cancer types studied to date, and suggest further strategies to comprehensively elucidate the roles of IL-32 in a context-dependent manner.

Insights into the role of IL-32 in cancer

Interleukin 32 (IL-32) is a proinflammatory cytokine involved in the development of several diseases, including cancer. IL-32 is a rather peculiar cytokine because its protein structure does not show resemblance with any of the known cytokines, and an IL-32 receptor to facilitate extracellular signaling has not yet been identified. Thus far, 9 isoforms of IL-32 have been described, all of which show differences in terms of effects and in potency to elicit a specific effect. Since the first report of IL-32 in 2005, there is increasing evidence that IL-32 plays an important role in the pathophysiology of both hematologic malignancies and solid tumors. Some IL-32 isoforms have been linked to disease outcome and were shown to positively influence tumor development and progression in various different malignancies, including gastric, breast and lung cancers. However, there are other reports suggesting a tumor suppressive role for some of IL-32 as well. For example, IL-32γ and IL-32β expression is associated with increased cancer cell death in colon cancer and melanoma, whereas expression of these isoforms is associated with increased invasion and migration in breast cancer cells. Furthermore, IL-32 isoforms α, β and γ also play an important role in regulating the anti-tumor immune response, thus also influencing tumor progression. In this review, we provide an overview of the role of IL-32 and its different isoforms in carcinogenesis, invasion and metastasis, angiogenesis and regulation of the anti-tumor immune response.

VHL and Hypoxia Signaling: Beyond HIF in Cancer

Von Hippel-Lindau (VHL) is an important tumor suppressor that is lost in the majority of clear cell carcinoma of renal cancer (ccRCC). Its regulatory pathway involves the activity of E3 ligase, which targets hypoxia inducible factor α (including HIF1α and HIF2α) for proteasome degradation. In recent years, emerging literature suggests that VHL also possesses other HIF-independent functions. This review will focus on VHL-mediated signaling pathways involving the latest identified substrates/binding partners, including N-Myc downstream-regulated gene 3 (NDRG3), AKT, and G9a, etc., and their physiological roles in hypoxia signaling and cancer. We will also discuss the crosstalk between VHL and NF-κB signaling. Lastly, we will review the latest findings on targeting VHL signaling in cancer.