OFD1, oral-facial digital syndrome type 1, is a component of the centrosome and is associated with the centrioles throughout the cell cycle. OFD1 plays an important role in the process of forming primary cilia. Bardet–Biedl syndrome (BBS) is a prototypical human genetic disorder associated with ciliary dysfunction. Seven of the most evolutionarily conserved BBS proteins (BBS1, 2, 4, 5, 7, 8, and 9) form a stable complex, called the BBSome, which has been defined as a coat complex transporting membrane proteins between plasma and ciliary membranes.

The exome sequencing data from our collaborative project to study lung cancer metastasis suggest that ciliogenesis genes may be involved in lung cancer metastasis. Others’ studies indicate that cilia may play important roles in cance...[ Read more ]

OFD1, oral-facial digital syndrome type 1, is a component of the centrosome and is associated with the centrioles throughout the cell cycle. OFD1 plays an important role in the process of forming primary cilia. Bardet–Biedl syndrome (BBS) is a prototypical human genetic disorder associated with ciliary dysfunction. Seven of the most evolutionarily conserved BBS proteins (BBS1, 2, 4, 5, 7, 8, and 9) form a stable complex, called the BBSome, which has been defined as a coat complex transporting membrane proteins between plasma and ciliary membranes.

The exome sequencing data from our collaborative project to study lung cancer metastasis suggest that ciliogenesis genes may be involved in lung cancer metastasis. Others’ studies indicate that cilia may play important roles in cancer development. However, the roles and mechanisms of cilia in cancer are not clear. Therefore, my research project aimed to elucidate the relationship between lung cancer cell migration and the ciliogenesis genes OFD1 and BBS4.

The results from our cell proliferation assay using crystal violet, colony formation assay and EdU assays showed that knockdown of OFD1 or BBS4 had no effect on cell proliferation. Fluorescence-activated cell sorting (FACS) indicated that knockdown of OFD1 or BBS4 had no impact on the cell cycle distribution of the cells. On the other hand, compared with negative control cells, the percentage of ciliated cells was reduced in A549 cells transfected with siOFD1 or siBBS4. Moreover, knockdown of OFD1 or BBS4 strongly inhibited cell migration and invasion. Immunofluorescence assay was used to detect the relationship between cell migration and cilia. Interestingly, we found that the cells in the first row of the migration edge had a higher percentage of ciliated cells than internal cells. After the cells were transfected with siOFD1 or BBS4, the percentage of ciliated cells in the first row was reduced compared with negative control during cell migration. Our data suggest that OFD1 and BBS4 are needed for primary cilia formation, and cilia play an important role in lung cancer cell invasion and migration. Furthermore, silencing OFD1 or BBS4 inhibited cilia-dependent cell migration promoted by PDGF-AA and PDGFRα signaling by suppressing the Akt and ERK1/2 pathways. Further study is expected to produce significant results in the understanding of the mechanisms of cancer metastasis mediated by cilia.

Previous studies have indicated that the combination of natural products and chemotherapy agents can improve the sensitivity and cytotoxicity of chemotherapy agents towards cancer cells. Phytochemical investigation of the stem of Urceola huaitingii resulted in the isolation of nine proanthocyanidins (1-9). Here we evaluated the anticancer activities of proanthocyanidins (UH-1-9) and their synergistic anticancer effects in combination with chemotherapeutics. The results showed that some proanthocyanidins, especially compound UH-7 possessing two doubly interflavonoid linkages, exhibited significantly synergistic anticancer effects with some chemotherapeutics in human gastric cancer cell line HGC27. Further results from dosage-activity studies using WST-1 (Water-soluble tetrazolium salt) assay to quantify viable cell numbers and isobolographic analysis demonstrated that the combination of UH-7 and Doxorubicin significantly resulted in synergistic cytotoxic effects towards HGC27 cells. Flow cytometry analysis suggested that the combination treatment had no obvious influence on cell cycle distribution. However, the flow cytometry and immunoblotting assay indicated that UH-7 enhanced Doxorubicin-mediated apoptosis. More importantly, UH-7 enhanced the intracellular Doxorubicin accumulation in HGC27 cells. The combined treatment remarkably increased cytochrome C release and activated caspase-3 and caspase-9. Furthermore, we show that while treatment with doxorubicin activated Akt, ERK1/2 and p38 signaling pathways, UH-7 in the combination treatment with doxorubicin diminished Akt, ERK1/2 and p38. In conclusion, our studies demonstrate that combination of UH-7 and Doxorubicin synergistically induces mitochondria-dependent apoptosis through inhibiting PI3K/Akt, ERK1/2 and p38 pathways in HGC27 cells. Therefore, the combination of UH-7 with Doxorubicin may represent a potent therapy for gastric cancer.