Activity of roniciclib in medullary thyroid cancer

An Overview of CDK Enzyme Inhibitors in Cancer Therapy

The ability to address the cell cycle in cancer therapy brings up new medication development possibilities. Cyclin-dependent kinases are a group of proteins that control the progression of the cell cycle. The CDK/cyclin complexes are activated when specific CDK sites are phosphorylated. Because of their non-selectivity and severe toxicity, most first-generation CDK inhibitors (also known as pan-CDK inhibitors) have not been authorized for clinical usage. Despite this, significant progress has been made in allowing pan-CDK inhibitors to be employed in clinical settings. Pan-CDK inhibitors' toxicity and side effects have been lowered in recent years because of the introduction of combination therapy techniques. As a result of this, pan-CDK inhibitors have regained a lot of clinical potential as a combination therapy approach. The CDK family members have been introduced in this overview, and their important roles in cell cycle control have been discussed. Then, we have described the current state of CDK inhibitor research, with a focus on inhibitors other than CDK4/6. We have mentioned first-generation pan-CDKIs, flavopiridol and roscovitine, as well as second-generation CDKIs, dinaciclib, P276-00, AT7519, TG02, roniciclib, and RGB-286638, based on their research phases, clinical trials, and cancer targeting. CDKIs are CDK4/6, CDK7, CDK9, and CDK12 inhibitors. Finally, we have looked into the efficacy of CDK inhibitors and PD1/PDL1 antibodies when used together, which could lead to the development of a viable cancer treatment strategy.

CDK inhibitors in cancer therapy, an overview of recent development

Dysregulated cell division, which leads to aberrant cell proliferation, is one of the key hallmarks of cancer. Therefore, therapeutic targets that block cell division would be effective for cancer treatment. Cell division is mainly controlled by a complex composed of cyclin and cyclin dependent kinases (CDKs). To date, the CDK inhibitors (CDKIs), specifically the ones that block the enzyme activity of CDK4 and CDK6 (CDK4/6), have been approved by FDA for the treatment of metastatic hormone receptor positive breast cancer. However, due to the non-selectivity and significant toxicity, most of the first generation CDK inhibitors (so called pan-CDK inhibitors that target several CDKs), have not been approved for clinical application. Despite this, great efforts and progress have been made to enable pan-CDK inhibitors application in the clinical setting. Notably, the development of combination therapy strategies in recent years has made it possible to reduce the toxicity and side effects of pan-CDK inhibitors. Thus, as a combination therapy approach, pan-CDK inhibitors regain great potential in clinical application. In this review, we introduced the CDK family members and discussed their major functions in cell cycle controlling. Then, we summarized the research progress regarding CDK inhibitors, especially those other than CDK4/6 inhibitors. We reviewed first-generation pan-CDKIs Flavopiridol and Roscovitine, and second-generation CDKIs Dinaciclib, P276-00, AT7519, TG02, Roniciclib, RGB-286638 by focusing on their developing stages, clinical trials and targeting cancers. The specific CDKIs, which targets to increase specificity and decrease the side effects, were also discussed. These CDKIs include CDK4/6, CDK7, CDK9, and CDK12/13 inhibitors. Finally, the efficacy and discrepancy of combination therapy with CDK inhibitors and PD1/PDL1 antibodies were analyzed, which might give insights into the development of promising strategy for cancer treatment.

New Hybrid Scaffolds Based on Carbazole-Chalcones as Potent Anticancer Agents

BACKGROUND AND OBJECTIVES

Despite various technological advances for the treatment of cancer, the identification of new chemical entities with potent anticancer effects remain an indispensable requirement of the time due to multi-drug resistance exhibited by previously developed anticancer drugs. Particularly, the hybrid drugs incorporating two individual bioactive pharmacophores present medicinally important structural leads, thus improving the pharmacodynamic profile of the drug molecules. The antiproliferative and pro-apoptotic activity of the carbazole-chalcone hybrids on human breast and cervical cancer cells will be examined.

MATERIALS AND METHODS

To overcome such complications, in the current study, we evaluated the cytotoxic effects of carbazole-chalcone hybrids on human breast adenocarcinoma (MCF-7), cervical adenocarcinoma (HeLa) cells and normal cells, i.e., Baby Hamster Kidney cells (BHK-21) using MTT (dimethyl-2-thiazolyl-2,5- diphenyl-2H-tetrazolium bromide) assay. The mechanistic studies were performed on potent compound 4g by fluorescent microscopic studies, release of Lactate Dehydrogenase (LDH) and mitochondrial membrane potential, activation of caspase-9 and -3 and flow cytometric analysis.

RESULTS

As revealed by MTT assay, compound 4g was identified as the most potent derivative among the tested series with IC₅₀ values of 5.64 and 29.15μM against HeLa and MCF-7 cells, respectively. The results were compared with cisplatin. Fluorescent microscopic studies using 4',6-diamidino-2-phenylindole (DAPI) and Propidium Iodide (PI) staining confirmed the occurrence of apoptosis in HeLa cells treated with the most active compound 4g. Moreover, compound 4g also triggered the release of Lactate Dehydrogenase (LDH) in treated HeLa and MCF-7 cells while a fluorescence assay displayed a remarkable increase in the activity of caspase-9 and -3. Moreover, flow cytometric results revealed that compound 4g caused G₀/G₁ arrest in the treated HeLa cells.

CONCLUSION

Our results demonstrated that the compound 4g possesses chemotherapeutic properties against breast cancer and cervical adenocarcinoma cells, thus warranting further research to test the anticancer potential of this compound at preclinical and clinical level.

In Vitro Anticancer Effects of Stilbene Derivatives: Mechanistic Studies on HeLa and MCF-7 Cells

BACKGROUND AND OBJECTIVE

The growing prevalence of cancer and the resulting chemoresistance exert a huge burden on healthcare systems and impose a great challenge to public health around the world. In efforts to develop new chemotherapeutic agents for cancer treatment, a class of heterocyclic compounds i.e. triazine-based molecules were investigated as anticancer agents.

MATERIALS AND METHODS

New triazine hybrids of stilbene were synthesized and evaluated as anticancer agents for cervical (HeLa) and breast (MCF-7) carcinoma cells. The compound (7e), sodium (E)-6,6'-(ethene-1,2- diyl)bis(3-((4-chloro-6-((3-luorophenyl)amino)-1,3,5-triazin-2-yl)amino)benzenesulfonate) was found to be most potent among synthesized derivatives and was explored further for detailed mechanistic studies.

RESULTS

In a set comprised of twelve derivatives, compound 7e, sodium (E)-6,6'-(ethene-1,2-diyl)bis(3-((4- chloro-6-((3-luorophenyl)amino)-1,3,5-triazin-2-yl)amino)benzenesulfonate) was found most potent inhibitor for HeLa and MCF-7 cells.

DISCUSSION

The present study has revealed that compound 7e may activate mitochondrial pathway of apoptosis in HeLa and MCF-7 cells which was assessed by DNA binding studies, estimation of the release of Lactate Dehydrogenase (LDH), fluorescence imaging, production of Reactive Oxygen Species (ROS) in cancer cells, analysis of cell cycle by flow cytometry, change in Mitochondrial Membrane Potential (MMP) and activation of caspase-9 and caspase-3.

CONCLUSION

Compound 7e may serve as a lead in designing new anticancer compounds based on stilbene scaffold.

Curcumin rescue p53Y220C in BxPC-3 pancreatic adenocarcinomas cell line: Evidence-based on computational, biophysical, and in vivo studies

BACKGROUND

The p53, tumor suppressor protein is inactivated upon mutation in the DNA-binding domain and the non-functional protein leads to cancers. The p53Y220C is one of the most frequently observed mutations in p53 with a scope of rescuing the protein function using small molecules.

METHODS

Using computational modeling, biophysical, and experimental cell-based studies we tried to understand the molecular basis of Curcumin as a potential small molecule to stabilize p53Y220C mutant and restore its function. The pancreatic adenocarcinomas BxPC-3 p53Y220C mutant cell line was used for cell-based assays to determine the therapeutic potential of Curcumin to restore mutant p53 to function like wild type.

RESULTS

Our results showed that the Curcumin binds p53Y220C with K_d = 3.169 ± 0.257 μM and it increases the DNA binding affinity of the mutant by 4-fold with K_d = 851.29 ± 186.27 nM. By Fluorescence, CD, and IR spectroscopy, we could characterize the secondary structural changes and stabilization of the p53Y220C DNA binding domain upon Curcumin binding. By caspase-3 and Annexin V assays, we could demonstrate that Curcumin at 3 μM to 8 μM concentration could initiate p53 mediated apoptosis in BxPC-3 cell line. Based on our experimental studies, we propose a mechanism for the activation of ATM/Chk1 kinases pathways for apoptosis and/or G2/M cell cycle arrest in the BxPC-3 cell line mediated by functionally restored p53Y220C.

CONCLUSION

The study indicated that the natural compound Curcumin could rescue mutant p53Y220C in BxPC-3 pancreatic adenocarcinomas cell line to function like wild-type and activate apoptotic pathways.

Roniciclib down-regulates stemness and inhibits cell growth by inducing nucleolar stress in neuroblastoma

Neuroblastoma, an embryonic tumor arising from neuronal crest progenitor cells, has been shown to contain a population of undifferentiated stem cells responsible for the malignant state and the unfavorable prognosis. Although many previous studies have analyzed neuroblastoma stem cells and their therapeutic targeting, this topic appears still open to novel investigations. Here we found that neurospheres derived from neuroblastoma stem-like cells showed a homogeneous staining for several key nucleolar proteins, such as Nucleolin, Nucleophosmin-1, Glypican-2 and PES-1. We investigated the effects of Roniciclib (BAY 1000394), an anticancer stem cells agent, on neurospheres and on an orthotopic neuroblastoma mouse model, discovering an impressive inhibition of tumor growth and indicating good chances for the use of Roniciclib in vivo. We demonstrated that Roniciclib is not only a Wnt/β-catenin signaling inhibitor, but also a nucleolar stress inducer, revealing a possible novel mechanism underlying Roniciclib-mediated repression of cell proliferation. Furthermore, we found that high expression of Nucleophosmin-1 correlates with patients’ short survival. The co-expression of several stem cell surface antigens such as CD44v6 and CD114, together with the nucleolar markers here described, extends new possibilities to isolate undifferentiated subpopulations from neuroblastoma and identify new targets for the treatment of this childhood malignancy.

Field rates of Sivanto™ (flupyradifurone) and Transform® (sulfoxaflor) increase oxidative stress and induce apoptosis in honey bees (Apis mellifera L.)

Pesticide exposures can have detrimental impacts on bee pollinators, ranging from immediate mortality to sub-lethal impacts. Flupyradifurone is the active ingredient in Sivanto™ and sulfoxaflor is the active ingredient in Transform®. They are both relatively new insecticides developed with an intent to reduce negative effects on bees, when applied to bee-attractive crops. With the growing concern regarding pollinator health and pollinator declines, it is important to have a better understanding of any potential negative impacts, especially sub-lethal, of these pesticides on bees. This study reports novel findings regarding physiological stress experienced by bees exposed to field application rates of these two insecticides via a Potter Tower sprayer. Two contact exposure experiments were conducted-a shorter 6-hour study and a longer 10-day study. Honey bee mortality, sugar syrup and water consumption, and physiological responses (oxidative stress and apoptotic protein assays) were assessed in bees exposed to Sivanto™ and Transform®, and compared to bees in control group. For the longer, 10-day contact exposure experiment, only the Sivanto™ group was compared to the control group, as high mortality recorded in the sulfoxaflor treatment group during the shorter contact exposure experiment, made the latter group unfeasible to test in the longer 10-days experiment. In both the studies, sugar syrup and water consumptions were significantly different between treatment groups and controls. The highest mortality was observed in Transform® exposed bees, followed by the Sivanto™ exposed bees. Estimates of reactive oxygen/nitrogen species indicated significantly elevated oxidative stress in both pesticide treatment groups, when compared to controls. Caspase-3 protein assays, an indicator of onset of apoptosis, was also significantly higher in the pesticide treatment groups. These differences were largely driven by post exposure duration, indicating sub-lethal impacts. Further, our findings also emphasize the need to revisit contact exposure impacts of Sivanto™, given the sub-lethal impacts and mortality observed in our long-term (10-day) contact exposure experiment.

MiR-376c-3p targets heparin-binding EGF-like growth factor (HBEGF) to inhibit proliferation and invasion in medullary thyroid carcinoma cells

INTRODUCTION

Aggressive medullary thyroid carcinomas (MTC) have a high mortality rate and the treatment for patients diagnosed with advanced MTC is comparatively ineffective. We hence aimed to test the effects of miR-376c-3p on MTC and to explore the relevant mechanism.

MATERIAL AND METHODS

Cell Counting Kit-8 (CCK-8) and soft agar colony formation assay were applied to evaluate the proliferation of transfected MZ-CRC-1 cells. Wound healing and transwell assay were employed to evaluate MTC cell migration and invasion, respectively. Luciferase assay was performed to validate the downstream target of miR-376c-3p in MZ-CRC-1 cells. Quantitative polymerase chain reaction was used to detect mRNA abundance of key genes. Western blot technique was used to analyze protein levels of HBEGF, E-cadherin, ZO-1, N-cadherin and vimentin.

RESULTS

MiR-376c-3p inhibited the viability, migration and invasion of MZ-CRC-1 cells. Moreover, miR-376c-3p mimic downregulated expression of N-cadherin and vimentin but upregulated that of E-cadherin and ZO-1 in MZ-CRC-1 cells. Results for the luciferase reporter assay showed that miR-376c-3p was able to bind the 3' untranslated region of heparin-binding EGF-like growth factor (HBEGF), of which overexpression nearly nullified the miR-376c-3p mimic-induced inhibitory effects in the MTC cells.

CONCLUSIONS

MiR-376c-3p showed suppressive effects on MZ-CRC-1 cells via targeting and downregulating HBEGF, suggesting that miR-376c-3p could potentially be targeted for the treatment of MTC.

Synthesis, characterization, and anticancer activity of Schiff bases

Five Schiff bases, 2-((3-chlorophenylimino)methyl)-5-(diethylamino)phenol (L1), 2-((2,4-dichlorophenylimino)methyl)-5-(diethylamino)phenol (L2), 5-(diethylamino)-2-((3,5-dimethylphenylimino)methyl)phenol (L3), 2-((2-chloro-4-methylphenylimino)methyl)-5-(diethylamino)phenol (L4), and 5-(diethylamino)-2-((2,6-diethylphenylimino)methyl)phenol (L5) were synthesized and characterized by elemental analysis, FT-IR, ¹H and ¹³C NMR spectroscopy. Three of the compounds (L1, L2, and L4) were analyzed by single crystal X-ray diffraction: L1 and L2 crystallized in orthorhombic P2₁2₁2₁ and Pca2₁ space group, respectively, while L4 crystallized in monoclinic P2₁/c space group. Theoretical investigations were performed for all the synthesized compounds to evaluate the structural details. Drug-DNA interaction studies results from UV-Vis spectroscopy and electrochemistry complement that the compounds bind to DNA through electrostatic interactions. The cytotoxicity of the synthesized compounds was studied against cancer cell lines (HeLa and MCF-7) and a normal cell line (BHK-21) by means of an MTT assay compared to carboplatin, featuring IC₅₀ values in the micromolar range. The pro-apoptotic mechanism for the active compound L5 was evaluated by fluorescence microscopy, cell cycle analysis, caspase-9 and -3 activity, reactive oxygen species production, and DNA binding studies that further strengthen the results of that L5 is a potent drug against cancer.Communicated by Ramaswamy H. Sarma.

Recent development of CDK inhibitors: An overview of CDK/inhibitor co-crystal structures

The cyclin-dependent protein kinases (CDKs) are protein-serine/threonine kinases that display crucial effects in regulation of cell cycle and transcription. While the excessive expression of CDKs is intimate related to the development of diseases including cancers, which provides opportunities for disease treatment. A large number of small molecules are explored targeting CDKs. CDK/inhibitor co-crystal structures play an important role during the exploration of inhibitors. So far nine kinds of CDK/inhibitor co-crystals have been determined, they account for the highest proportion among the Protein Data Bank (PDB) deposited crystal structures. Herein, we review main co-crystals of CDKs in complex with corresponding inhibitors reported in recent years, focusing our attention on the binding models and the pharmacological activities of inhibitors.

Mouse models in endocrine tumors

Endocrine and neuroendocrine tumors comprise a highly heterogeneous group of neoplasms that can arise from (neuro)endocrine cells, either from endocrine glands or from the widespread diffuse neuroendocrine system, and, consequently, are widely distributed throughout the body. Due to their diversity, heterogeneity and limited incidence, studying in detail the molecular and genetic alterations that underlie their development and progression is still a highly elusive task. This, in turn, hinders the discovery of novel therapeutic options for these tumors. To circumvent these limitations, numerous mouse models of endocrine and neuroendocrine tumors have been developed, characterized and used in pre-clinical, co-clinical (implemented in mouse models and patients simultaneously) and post-clinical studies, for they represent powerful and necessary tools in basic and translational tumor biology research. Indeed, different in vivo mouse models, including cell line-based xenografts (CDXs), patient-derived xenografts (PDXs) and genetically engineered mouse models (GEMs), have been used to delineate the development, progression and behavior of human tumors. Results gained with these in vivo models have facilitated the clinical application in patients of diverse breakthrough discoveries made in this field. Herein, we review the generation, characterization and translatability of the most prominent mouse models of endocrine and neuroendocrine tumors reported to date, as well as the most relevant clinical implications obtained for each endocrine and neuroendocrine tumor type.