Luciferase Reporter Cell Line - SN12-PM6

Primary cilia are present on renal tubules, and it is hypothesized that these cilia play a pivotal role in signal transduction during development. However, the oncogenic role of cilia in clear cell renal cell carcinoma (ccRCC) has yet to be elucidated. Here, researchers demonstrate that primary cilia are more prevalent in VHL-wild-type ccRCC cell lines, and that a high frequency of primary cilia is positively correlated with high VHL expression and poor prognosis. Furthermore, the knockdown of KIF3A and IFT88-key genes essential for ciliogenesis-significantly inhibits tumor proliferation and metastasis both in vitro and in vivo. Further analysis revealed that mutations in key genes within the Hedgehog signaling pathway are enriched in VHL-wild-type ccRCC, and that downstream signaling activation of this pathway is dependent on ciliogenesis. Moreover, either the removal of primary cilia or the pharmacological inhibition of Hedgehog signaling activation potently induces autophagic cell death. Collectively, these findings suggest that primary cilia hold promise as a diagnostic tool and provide novel insights into the mechanisms underlying disease progression in VHL-wild-type ccRCC. Targeting the "primary cilia–Hedgehog signaling pathway" axis represents a potentially effective therapeutic strategy for VHL-wild-type ccRCC.

Here, researchers investigated whether inhibiting ciliogenesis affects the tumorigenic and metastatic potential of ccRCC cells in vivo. Given that SN12-PM6 cells had previously been confirmed to effectively form tumors and metastasize in vivo, the researchers transfected luciferase-labeled SN12-PM6 cells with scramble, shIFT88, and shKIF3A vectors, respectively, and implanted them orthotopically beneath the renal capsule of mice. Four weeks later, the bioluminescence signals in the shIFT88 and shKIF3A groups were significantly lower than those in the scramble group (Figure 1g, h). Subsequently, ex vivo bioluminescence imaging was performed immediately after euthanizing the mice to monitor for lung metastasis. The results revealed the presence of metastatic foci in the lungs of the scramble group, whereas no metastasis was observed in the shIFT88 and shKIF3A groups (Figure 1i). H&E staining of the renal tissue not only confirmed that the tumor type was indeed ccRCC but also indicated that the tumor volumes in the shIFT88 and shKIF3A groups were significantly smaller than those in the scramble group (Figure 1j). Furthermore, H&E staining of the lung tissue confirmed the presence of metastatic foci in the lungs of the scramble group, while the shIFT88 and shKIF3A groups showed no signs of metastasis (Figure 1k). To further validate the efficiency of gene knockdown in vivo, the researchers examined cilia in the animal samples using Arl13b immunohistochemical staining. The results confirmed that the knockdown of the KIF3A and IFT88 genes indeed significantly inhibited ciliogenesis within the tumor tissue.

Figure 1. Inhibition of ciliogenesis suppresses VHL wild-type ccRCC growth and metastasis. (Tian S, et al., 2024)