Akt inhibition enhances the cytotoxic effect of apigenin in combination with PLX4032 in anaplastic thyroid carcinoma cells harboring BRAFV600E

Anticancer Effects and Molecular Mechanisms of Apigenin in Cervical Cancer Cells

Cervical cancer is the fourth most frequent malignancy in women. Apigenin is a natural plant-derived flavonoid present in common fruit, vegetables, and herbs, and has been found to possess antioxidant and anti-inflammatory properties as a health-promoting agent. It also exhibits important anticancer effects in various cancers, but its effects are not widely accepted by clinical practitioners. The present study investigated the anticancer effects and molecular mechanisms of apigenin in cervical cancer in vitro and in vivo. HeLa and C33A cells were treated with different concentrations of apigenin. The effects of apigenin on cell viability, cell cycle distribution, migration potential, phosphorylation of PI3K/AKT, the integrin β1-FAK signaling pathway, and epithelial-to-mesenchymal transition (EMT)-related protein levels were investigated. Mechanisms identified from the in vitro study were further validated in a cervical tumor xenograft mouse model. Apigenin effectively inhibited the growth of cervical cancer cells and cervical tumors in xenograft mice. Furthermore, the apigenin down-regulated FAK signaling (FAK, paxillin, and integrin β1) and PI3K/AKT signaling (PI3K, AKT, and mTOR), inactivated or activated various signaling targets, such as Bcl-2, Bax, p21^cip1, CDK1, CDC25c, cyclin B1, fibronectin, N-cadherin, vimentin, laminin, and E-cadherin, promoted mitochondrial-mediated apoptosis, induced G2/M-phase cell cycle arrest, and reduced EMT to inhibit HeLa and C33A cancer cell migration, producing anticancer effects in cervical cancer. Thus, apigenin may act as a chemotherapeutic agent for cervical cancer treatment.

Exploring the Natural Compounds in Flavonoids for Their Potential Inhibition of Cancer Therapeutic Target MEK1 Using Computational Methods

The Mitogen-Activated Protein Kinase (MAPK) signaling pathway plays an important role in cancer cell proliferation and survival. MAPKs' protein kinases MEK1/2 serve as important targets in drug designing against cancer. The natural compounds' flavonoids are known for their anticancer activity. This study aims to explore flavonoids for their inhibition ability, targeting MEK1 using virtual screening, molecular docking, ADMET prediction, and molecular dynamics (MD) simulations. Flavonoids (n = 1289) were virtually screened using molecular docking and have revealed possible inhibitors of MEK1. The top five scoring flavonoids based on binding affinity (highest score for MEK1 is -10.8 kcal/mol) have been selected for further protein-ligand interaction analysis. Lipinski's rule (drug-likeness) and absorption, distribution, metabolism, excretion, and toxicity predictions were followed to find a good balance of potency. The selected flavonoids of MEK1 have been refined with 30 (ns) molecular dynamics (MD) simulation. The five selected flavonoids are strongly suggested to be promising potent inhibitors for drug development as anticancer therapeutics of the therapeutic target MEK1.

Combinatorial Therapies in Thyroid Cancer: An Overview of Preclinical and Clinical Progresses

Accounting for about 2% of cancers diagnosed worldwide, thyroid cancer has caused about 41,000 deaths in 2018. Despite significant progresses made in recent decades in the treatment of thyroid cancer, many resistances to current monotherapies are observed. In our complete review, we report all treatments that were tested in combination against thyroid cancer. Many preclinical studies investigating the effects of inhibitors of the MAPK and PI3K pathways highlighted the importance of mutations in such signaling pathways and their impacts on the subsequent efficacy of targeted therapies, thus reinforcing the need of more personalized therapeutic strategies. Our review also points out the multiple possibilities of combinatory strategies, particularly using therapies targeting proliferation, survival, angiogenesis, and in combination with conventional treatments such as chemotherapies. In any case, resistances to anticancer therapies always develop through the activation of alternative signaling pathways. Combinatory treatments aim to blockade such mechanisms, which are gradually decrypted, thus offering new perspectives for the future. The preclinical and clinical aspects of our review allow us to have a global opinion of the different therapeutic options currently evaluated in combination and to be aware about new perspectives of treatment of thyroid cancer.

Gemigliptin, a novel dipeptidyl peptidase-IV inhibitor, exerts a synergistic cytotoxicity with the histone deacetylase inhibitor PXD101 in thyroid carcinoma cells

PURPOSE

The influence of the dipeptidyl peptidase-IV inhibitor gemigliptin alone or in combination with the histone deacetylase inhibitor PXD101 on survival of thyroid carcinoma cells was investigated.

METHODS

SW1736, TPC-1, 8505C and BCPAP human thyroid carcinoma cells were used. To assess cell survival, cell viability, the percentage of viable cells and dead cells, cytotoxic activity, ATP levels and FACS analysis were measured. To validate the impact of gemigliptin combined with PXD101, the interactions were estimated by obtaining combination index in cells treated with two agents.

RESULTS

In cells treated with gemigliptin or PXD101, cell viability, the percentage of viable cells and ATP levels were reduced, and the percentage of dead cells and cytotoxic activity were elevated. In cells treated with both gemigliptin and PXD101, compared with PXD101 alone, cell death was augmented, and all of the combination index values were lower than 1.0, suggesting the synergism between gemigliptin and PXD101. The percentage of apoptotic cells, and the protein levels of Bcl2 and cleaved poly (ADP-ribose) polymerase were elevated, and the protein levels of xIAP and survivin were reduced. The protein levels of phospho-Akt and phospho-AMPK were elevated, and cell migration was reduced.

CONCLUSIONS

Our results demonstrate that gemigliptin induces cytotoxicity in thyroid carcinoma cells. Moreover, gemigliptin has a synergistic activity with PXD101 in the induction of cell death through involvement of Bcl2 family proteins, xIAP and survivin as well as mediation of Akt and AMPK in thyroid carcinoma cells.

Synergistic cytotoxicity of the dipeptidyl peptidase-IV inhibitor gemigliptin with metformin in thyroid carcinoma cells

PURPOSE

The influence of the dipeptidyl peptidase-IV inhibitor, gemigliptin alone or in combination with metformin on survival, proliferation, and migration of thyroid carcinoma cells was investigated.

METHODS

SW1736 and TPC-1 human thyroid carcinoma cells were used.

RESULTS

Gemigliptin and metformin caused cell death in a dose-dependent manner. In cells treated with both gemigliptin and metformin, compared with metformin alone, all of the combination index values were lower than 1.0, suggesting synergistic cytotoxicity of two agents. Cell viability, the percentage of viable cells, ATP levels, and mitochondrial membrane potential decreased; however, cytotoxic activity, and the protein levels of cleaved PARP, phospho-Akt and phospho-AMP-activated protein kinase (AMPK) increased. Administration of wortmannin, but not compound C, further decreased cell viability, and further increased cytotoxic activity. Moreover, compared with control, cell proliferation and migration as well as the protein levels of p53, p21, vascular cell adhesion molecule-1 (VCAM-1), and phospho-extracellular signal-regulated kinase (ERK) 1/2 decreased. The decrement of matrix metalloproteinase-2 and matrix metalloproteinase-9 protein levels was cell specific.

CONCLUSIONS

Our results demonstrate that gemigliptin induces cytotoxic activity, and has a synergistic activity with metformin in inducing cytotoxicity via regulation of Akt and AMPK in thyroid carcinoma cells. Furthermore, gemigliptin augments the inhibitory effect of metformin on proliferation and migration through involvement of matrix metalloproteinase-2, matrix metalloproteinase-9, p53, p21, VCAM-1, and ERK in thyroid carcinoma cells.

Correlative Studies in Clinical Trials: A Position Statement From the International Thyroid Oncology Group

OBJECTIVE

Patients with progressive thyroid cancer in distant metastatic sites represent a population with a need for new therapeutic options. Aspiring to improve the treatment of such patients, the objective of this position statement from the International Thyroid Oncology Group (ITOG) is to clarify the importance of incorporating high-quality correlative studies into clinical trials.

PARTICIPANTS

ITOG was formed to develop and support high-quality multicenter and multidisciplinary clinical trials for patients with aggressive forms of thyroid cancer. The Correlative Sciences Committee of the ITOG focuses on the quality and types of correlative studies included in ITOG-associated clinical trials.

EVIDENCE

This document represents expert consensus from ITOG regarding this issue based on extensive collective experience in clinical and translational trials informed by basic science.

CONSENSUS PROCESS

The Correlative Studies Committee identified an international writing group representative of diverse specialties, including basic sciences. Drafts were reviewed by all members of the writing group, the larger committee, and the ITOG board. After consideration of all comments by the writing group and modification of the document, the final document was then approved by the authors and the ITOG board.

CONCLUSIONS

High-quality correlative studies, which include variety in the types of correlates, should be intrinsic to the design of thyroid cancer clinical trials to offer the best opportunity for each study to advance treatment for patients with advanced and progressive thyroid cancer.

Apigenin in combination with Akt inhibition significantly enhances thyrotropin-stimulated radioiodide accumulation in thyroid cells

BACKGROUND

Selectively increased radioiodine accumulation in thyroid cells by thyrotropin (TSH) allows targeted treatment of thyroid cancer. However, the extent of TSH-stimulated radioiodine accumulation in some thyroid tumors is not sufficient to confer therapeutic efficacy. Hence, it is of clinical importance to identify novel strategies to selectively further enhance TSH-stimulated thyroidal radioiodine accumulation.

METHODS

PCCl3 rat thyroid cells, PCCl3 cells overexpressing BRAF(V600E), or primary cultured tumor cells from a thyroid cancer mouse model, under TSH stimulation were treated with various reagents for 24 hours. Cells were then subjected to radioactive iodide uptake, kinetics, efflux assays, and protein extraction followed by Western blotting against selected antibodies.

RESULTS

We previously reported that Akt inhibition increased radioiodine accumulation in thyroid cells under chronic TSH stimulation. Here, we identified Apigenin, a plant-derived flavonoid, as a reagent to further enhance the iodide influx rate increased by Akt inhibition in thyroid cells under acute TSH stimulation. Akt inhibition is permissive for Apigenin's action, as Apigenin alone had little effect. This action of Apigenin requires p38 MAPK activity but not PKC-δ. The increase in radioiodide accumulation by Apigenin with Akt inhibition was also observed in thyroid cells expressing BRAF(V600E) and in primary cultured thyroid tumor cells from TRβ(PV/PV) mice.

CONCLUSION

Taken together, Apigenin may serve as a dietary supplement in combination with Akt inhibitors to enhance therapeutic efficacy of radioiodine for thyroid cancer.