Activation of cyclin-dependent kinase activity is frequently observed in many human cancers; therefore, cyclin-dependent kinases that promote cell cycle transition and cell proliferation may be potential targets in the treatment of malignancy. The therapeutic effects of roniciclib, a cyclin-dependent kinase inhibitor for papillary and follicular thyroid cancer (designated as well-differentiated thyroid cancer), were investigated in this study. Roniciclib inhibited cell proliferation in two papillary and two follicular thyroid cancer cell lines in a dose-dependent manner. Roniciclib activated caspase-3 activity and induced apoptosis. Cell cycle progression was arrested in the G2/M phase. Roniciclib treatment in vivo retarded the growth of two well-differentiated thyroid tumors in xenograft models in a dose-dependent fashion. Furthermore, the combination of roniciclib with sorafenib was more effective than either single treatment in a follicular thyroid cancer xenograft model. Acceptable safety profiles appeared in animals treated with either roniciclib alone or roniciclib and sorafenib combination therapy. These findings support roniciclib as a potential drug for the treatment of patients with well-differentiated thyroid cancer.
Shu-Fu Lin, Jen-Der Lin, Chuen Hsueh, Ting-Chao Chou, and Richard J Wong
Shu-Fu Lin, Jen-Der Lin, Chun-Nan Yeh, Yu-Tung Huang, Ting-Chao Chou, and Richard J Wong
Polo-like kinases (PLKs) are pivotal regulators of cell proliferation and cell survival; therefore, PLKs may be potential targets in the treatment of malignancy. The therapeutic effects of volasertib, a PLKs inhibitor for papillary and follicular thyroid cancer (known as well-differentiated thyroid cancer (WDTC)), were evaluated in this study. Volasertib inhibited cell proliferation in two papillary and two follicular thyroid cancer cell lines in a dose-dependent manner. Volasertib treatment reduced cells in the S phase and increased cells in the G2/M phase. Volasertib activated caspase-3 activity and induced apoptosis. Drug combinations of volasertib and sorafenib showed mostly synergism in four well-differentiated thyroid carcinoma cell lines in vitro. Volasertib treatment in vivo retarded the growth of a papillary thyroid tumor model. Furthermore, the combination of volasertib with sorafenib was more effective than a single treatment of either in a follicular thyroid cancer xenograft model. Promising safety profiles appeared in animals treated with either volasertib alone or volasertib and sorafenib combination therapy. These findings support volasertib as a potential drug for the treatment of patients with WDTC.
Yu-Ling Lu, Yu-Tung Huang, Ming-Hsien Wu, Ting-Chao Chou, Richard J Wong, and Shu-Fu Lin
Wee1 is a kinase that regulates the G2/M progression by the inhibition of CDK1, which is critical for ensuring DNA damage repair before initiation of mitotic entry. Targeting Wee1 may be a potential strategy in the treatment of anaplastic thyroid cancer, a rare but lethal disease. The therapeutic effects of adavosertib, a Wee1 inhibitor for anaplastic thyroid cancer was evaluated in this study. Adavosertib inhibited cell growth in three anaplastic thyroid cancer cell lines in a dose-dependent manner. Cell cycle analysis revealed cells were accumulated in the G2/M phase. Adavosertib induced caspase-3 activity and led to apoptosis. Adavosertib monotherapy showed significant retardation of the growth of two anaplastic thyroid cancer tumor models. The combination of adavosertib with dabrafenib and trametinib revealed strong synergism in vitro and demonstrated robust suppression of tumor growth in vivo in anaplastic thyroid cancer xenograft models with BRAF V600E mutation. The combination of adavosertib with either sorafenib or lenvatinib also demonstrated synergism in vitro and had strong inhibition of tumor growth in vivo in an anaplastic thyroid cancer xenograft model. No appreciable toxicity appeared in mice treated with either a single agent or combination treatment. Our findings suggest adavosertib holds the promise for the treatment of patients with anaplastic thyroid cancer.
Trisha Dwight, Aidan Flynn, Kaushalya Amarasinghe, Diana E Benn, Richard Lupat, Jason Li, Daniel L Cameron, Annette Hogg, Shiva Balachander, Ida L M Candiloro, Stephen Q Wong, Bruce G Robinson, Anthony T Papenfuss, Anthony J Gill, Alexander Dobrovic, Rodney J Hicks, Roderick J Clifton-Bligh, and Richard W Tothill
Pheochromocytomas (PC) and paragangliomas (PGL) are endocrine tumors for which the genetic and clinicopathological features of metastatic progression remain incompletely understood. As a result, the risk of metastasis from a primary tumor cannot be predicted. Early diagnosis of individuals at high risk of developing metastases is clinically important and the identification of new biomarkers that are predictive of metastatic potential is of high value. Activation of TERT has been associated with a number of malignant tumors, including PC/PGL. However, the mechanism of TERT activation in the majority of PC/PGL remains unclear. As TERT promoter mutations occur rarely in PC/PGL, we hypothesized that other mechanisms – such as structural variations – may underlie TERT activation in these tumors. From 35 PC and four PGL, we identified three primary PCs that developed metastases with elevated TERT expression, each of which lacked TERT promoter mutations and promoter DNA methylation. Using whole genome sequencing, we identified somatic structural alterations proximal to the TERT locus in two of these tumors. In both tumors, the genomic rearrangements led to the positioning of super-enhancers proximal to the TERT promoter, that are likely responsible for the activation of the normally tightly repressed TERT expression in chromaffin cells