Anti-CUL3 monoclonal antibody, clone 4B9.2

Cullin 3 (CUL3), a molecular scaffold of Cullin-RING ubiquitin ligase, plays an important role in regulating biological processes through modulating the ubiquitylation and degradation of various protein substrates. Dysfunction of CUL3 is implicated in the development of several human diseases. However, the clinical significance and prognostic value of CUL3 in lung cancer have not been investigated. This study investigated the CUL3-modulating potential of non-small cell lung cancer cell lines, H1299, H358, H2170 and H520, by using immunoblotting, MTT, migration, invasion, colony formation and in vivo tumorigenicity assays. The prognostic significance of CUL3 was measured by public KM plotter database () and tissue immunohistochemistry analysis. The public online database analysis revealed that elevated mRNA expression of CUL3 was associated with better prognosis for non-small cell lung cancer and lung adenocarcinoma. In vitro experiments showed that ectopic overexpression of CUL3 significantly inhibited lung adenocarcinoma cell proliferation and migration, and the tumor-suppressive effect of CUL3 was dependent on the Nrf2/RhoA axis. In vivo mice model demonstrated that overexpression of CUL3 lead to a significant reduction of lung adenocarcinoma growth and metastasis. Importantly, tissue immunohistochemistry analysis showed that about 47% of non-small cell lung cancer tissues were expressed of CUL3 at high levels. Overexpression of CUL3 predicted favorable overall survival in non-small cell lung cancer patients, especially in lung adenocarcinoma, but not in lung squamous cell carcinoma patients. CUL3 could serve as a prognostic biomarker for lung adenocarcinoma. Loss of CUL3 might be driving tumorigenesis by activating the Nrf2/RhoA pathway.

Background: During fetal brain development in mammals, newborn neurons undergo cell migration to reach their appropriate positions and form functional circuits. We previously reported that the atypical RhoA GTPase Rnd2 promotes the radial migration of mouse cerebral cortical neurons (Nature 455(7209): 114-8, 2008; Neuron 69(6): 1069-84, 2011), but its downstream signalling pathway is not well understood. Results: We have identified BTB-domain containing adaptor for Cul3-mediated RhoA degradation 2 (Bacurd2) as a novel interacting partner to Rnd2, which promotes radial migration within the developing cerebral cortex. We find that Bacurd2 binds Rnd2 at its C-terminus, and this interaction is critical to its cell migration function. We show that forced expression or knockdown of Bacurd2 impairs neuronal migration within the embryonic cortex and alters the morphology of immature neurons. Our in vivo cellular analysis reveals that Bacurd2 influences the multipolarto-bipolar transition of radially migrating neurons in a cell autonomous fashion. When we addressed the potential signalling relationship between Bacurd2 and Rnd2 using a Bacurd2-Rnd2 chimeric construct, our results suggest that Bacurd2 and Rnd2 could interact to promote radial migration within the embryonic cortex. Conclusions: Our studies demonstrate that Bacurd2 is a novel player in neuronal development and influences radial migration within the embryonic cerebral cortex.