SENP2 exerts an anti‑tumor effect on chronic lymphocytic leukemia cells through the inhibition of the Notch and NF‑κB signaling pathways

Abstract

Chronic lymphocytic leukemia (CLL) is one of the most often diagnosed hematological malignant tumors in the Western world and a type of inert B-cell lymphoma that commonly attacks the elderly. Small ubiquitin related modifier (SUMO)-specific protease 2 (SENP2) can act as a suppressor in various types of cancer by regulating the stability of β-catenin to affect the Notch signaling pathway; however, it has a low expression level in CLL cells. In this study, we firstly used western blot analysis and RT-qPCR to detect the protein and mRNA expression levels of SENP2 in the peripheral blood of patients with CLL and healthy volunteers. Secondly, we overexpressed or knocked down the expression of SENP2 in CLL cells and then determined the cell invasive and chemotactic ability in a Transwell assay and chemotaxis assay. We examined the sensitivity of the cells to cytarabine and dexamethasone via a CCK-8 assay and determined the cell apoptotic condition and the expression of the Notch signaling pathway using flow cytometry and western blot analysis. The results demonstrated that the patients with CLL had relatively low expression levels of SENP2. The overexpression of SENP2 in the CLL cells decreased their invasive and proliferative ability, as well as their chemotactic response and enhanced their sensitivity to cytarabine and dexamethasone, while it promoted cell apoptosis. The silencing of SENP2 in the CLL cells generally produced the opposite results. We thus hypothesized that the overexpression of SENP2 downregulated β-catenin expression, thus inhibiting the Notch signaling pathway in CLL cells. Moreover, the nuclear factor (NF)-κB signaling pathway was also regulated by the overexpression of SENP2. On the whole, the findings of this study indicate tha SENP2 can act as a tumor suppressor in CLL cells, and may thus prove to be a novel target for CLL treatment in clinical practice.

Therapeutic Potential of Targeting the SUMO Pathway in Cancer

“…However, high expression has been associated with better prognosis in some cancer types. Downregulated expression levels in cancer tissues have consistently been reported for SENP2 [52][53][54][55][56][57] and PIAS2 [58][59][60]. The prognostic value of a single SUMO machinery component can also vary between cancer (sub)types, and, e.g., the value for PC2 [61,62] and PIAS4 [63,64] as prognostic biomarkers in breast cancer and for PIAS3 [65,66] in mesothelioma remains ambiguous (Table 1).…”

Comprehensive in silico analysis for identification of novel candidate target genes, including DHX36, OPA1, and SENP2, located on chromosome 3q in head and neck cancers

“…74 However, the function of SENP2 in carcinogenesis seems to be controversial, since many other researches demonstrated its tumor suppressive potential. [78][79][80] Considering these contradictory findings, investigation of oncogenic vs tumor suppression potential of SENP2 in HNSC in vitro and in vivo will help pave the road for better understanding its contribution to head and neck pathogenesis.…”

“…More importantly, SENP2 was found to inhibit the SUMOylation levels of CREB‐binding protein (CBP) or murine double minute 2 (Mdm2) to promote cell cycle progression via inducing p53 degradation 74 . However, the function of SENP2 in carcinogenesis seems to be controversial, since many other researches demonstrated its tumor suppressive potential 78‐80 . Considering these contradictory findings, investigation of oncogenic vs tumor suppression potential of SENP2 in HNSC in vitro and in vivo will help pave the road for better understanding its contribution to head and neck pathogenesis.…”

SENP Proteases as Potential Targets for Cancer Therapy

“…SENP2 regulated β-catenin, which plays an essential role in the transduction of Wnt signaling in hepatocellular carcinoma and bladder cancer cells [ 18 , 19 ]. SENP2 inhibited the Notch and NF-κB signaling pathways in chronic lymphocytic leukemia cells, resulting in cell apoptosis [ 49 ]. In breast cancer cells, SENP2 participated in the regulation of estrogen receptor α (ERα) signaling and transforming growth factor (TGF-β) signaling, which modulated cancer cell proliferation, migration, and invasion [ 50 , 51 ].…”