CDK Inhibitors and FDA: Approved and Orphan.

The protein kinases are a large family of enzymes which catalyze protein phosphorylation at certain amino acids [...].

SGK1 in Cancer: Biomarker and Drug Target.

Serum- and glucocorticoid-regulated kinases (SGKs) are members of the AGC family of serine/threonine kinases, consisting of three isoforms: SGK1, SGK2, and SGK3. SGK1 was initially cloned as a gene transcriptionally stimulated by serum and glucocorticoids in rat mammary tumor cells. It is upregulated in some cancers and downregulated in others. SGK1 increases tumor cell survival, adhesiveness, invasiveness, motility, and epithelial to mesenchymal transition. It stimulates tumor growth by mechanisms such as activation of K+ channels and Ca2+ channels, Na+/H+ exchanger, amino acid and glucose transporters, downregulation of Foxo3a and p53, and upregulation of ß-catenin and NFκB. This chapter focuses on major aspects of SGK1 involvement in cancer, its use as biomarker as well as potential therapeutic target.

Starvation mediates pancreatic cancer cell sensitivity to ferroptosis via ERK1/2, JNK and changes in the cell mesenchymal state.

Pancreatic cancer is a highly metastatic and therapy­resistant disease. In the present study, the prospects of a novel approach to kill pancreatic cancer cells were examined: Starvation combined with ferroptosis induction. Established pancreatic cancer cell lines (Miapaca2, Panc­1, Su.86.86 and T3M4), as well as a unique cell line, Capan­26, which was originally derived in the authors' laboratory, were used. Cells were deprived from growth factors, amino acids and pseudo­starved using treatment with mTOR inhibitors; erastin was used to induce ferroptosis. Cell viability and lipid peroxidation measurements using flow cytometry revealed that the starved pancreatic cancer cells reacted differently to ferroptosis induction: The Panc­1, Su.86.86 and T3M4 cells gained sensitivity, while the Miapaca2 cells acquired resistance. Fluorescence microscopy revealed that ERK1/2 translocated to the nucleus of the starved pancreatic cancer cells. Moreover, ERK1/2 pharmacological inhibition with SCH772984 prevented erastin­induced ferroptosis in the starved Panc­1, Su.86.86 and T3M4 cells. Confocal microscopy also indicated JNK activation. However, the inhibition of this kinase revealed its unexpected role in oxidative stress management: Treatment with the JNK inhibitor, SP600125, increased the viability of pseudo­starved cells following erastin treatment. In addition, the FBS­starved Miapaca2 and Capan­26 cells transitioned between epithelial and mesenchymal cell states. The results were further confirmed using wound healing assays, western blot analysis and microscopic analysis of epithelial­to­mesenchymal transition (EMT) markers. Mesenchymal properties were associated with a higher sensitivity to erastin, whereas epithelial­like cells were more resistant. Finally, it was demonstrated that compounds targeting EMT­related signaling pathways increased cell sensitivity to erastin. On the whole, these results confirm that in starved pancreatic cancer cells, ERK1/2 and JNK signaling, as well as switching between epithelial and mesenchymal states mediates sensitivity to erastin and reveal novel therapeutic prospects of the combination of starvation with ferroptosis induction.

Anti-Cancer Drugs Targeting Protein Kinases Approved by FDA in 2020.

Cancers are a large group of diseases that mostly emerge because of the uncontrollable action of many different genes in human cells [...].

Proteomic Analysis of Breast Cancer Resistance to the Anticancer Drug RH1 Reveals the Importance of Cancer Stem Cells.

Antitumor drug resistance remains a major challenge in cancer chemotherapy. Here we investigated the mechanism of acquired resistance to a novel anticancer agent RH1 designed to be activated in cancer cells by the NQO1 enzyme. Data show that in some cancer cells RH1 may act in an NQO1-independent way. Differential proteomic analysis of breast cancer cells with acquired resistance to RH1 revealed changes in cell energy, amino acid metabolism and G2/M cell cycle transition regulation. Analysis of phosphoproteomics and protein kinase activity by multiplexed kinase inhibitor beads showed an increase in the activity of protein kinases involved in the cell cycle and stemness regulation and downregulation of proapoptotic kinases such as JNK in RH1-resistant cells. Suppression of JNK leads to the increase of cancer cell resistance to RH1. Moreover, resistant cells have enhanced expression of stem cell factor (SCF) and stem cell markers. Inhibition of SCF receptor c-KIT resulted in the attenuation of cancer stem cell enrichment and decreased amounts of tumor-initiating cells. RH1-resistant cells also acquire resistance to conventional therapeutics while remaining susceptible to c-KIT-targeted therapy. Data show that RH1 can be useful to treat cancers in the NQO1-independent way, and targeting of the cancer stem cells might be an effective approach for combating resistance to RH1 therapy.

Non-Coding RNAs in Glioma.

Glioma is the most aggressive brain tumor of the central nervous system. The ability of glioma cells to migrate, rapidly diffuse and invade normal adjacent tissue, their sustained proliferation, and heterogeneity contribute to an overall survival of approximately 15 months for most patients with high grade glioma. Numerous studies indicate that non-coding RNA species have critical functions across biological processes that regulate glioma initiation and progression. Recently, new data emerged, which shows that the cross-regulation between long non-coding RNAs and small non-coding RNAs contribute to phenotypic diversity of glioblastoma subclasses. In this paper, we review data of long non-coding RNA expression, which was evaluated in human glioma tissue samples during a five-year period. Thus, this review summarizes the following: (I) the role of non-coding RNAs in glioblastoma pathogenesis, (II) the potential application of non-coding RNA species in glioma-grading, (III) crosstalk between lncRNAs and miRNAs (IV) future perspectives of non-coding RNAs as biomarkers for glioma.

Proteomic Identification of FLT3 and PCBP3 as Potential Prognostic Biomarkers for Pancreatic Cancer.

BACKGROUND/AIM: Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest types of cancer, particularly due to its aggressive course and challenging diagnostics in early-stage disease. The aim of this study was to discover new potential prognostic and diagnostic pancreatic cancer biomarkers. MATERIALS AND METHODS: The proteomes of 37 samples from pancreatic cancer, inflammatory or healthy pancreatic tissue derived through in-depth differential proteomic analysis were compared. RESULTS: A set of candidate proteins as pancreatic cancer-specific diagnostic or prognostic biomarkers were identified. Survival data of patients after two-year follow-up indicated FLT3 and PCBP3 proteins as potential biomarkers for favourable pancreatic cancer prognosis. The levels of PCBP3 correlated with tumour stage and FLT3 levels, were evaluated as independent prognostic marker. CONCLUSION: FLT3 and PCBP3 represent potential biomarkers for improved individualized pancreatic cancer prognosis. Moreover, FLT3 may play a role in future treatment selection.

Kinases and Cancer.

Protein kinases are a large family of enzymes catalyzing protein phosphorylation. The human genome contains 518 protein kinase genes, 478 of which belong to the classical protein kinase family and 40 are atypical protein kinases [...].

JNK, p38, ERK, and SGK1 Inhibitors in Cancer.

Mitogen-activated protein kinases (MAP kinases) are a family of kinases that regulates a range of biological processes implicated in the response to growth factors like latelet-derived growth factor (PDGF), epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), and stress, such as ultraviolet irradiation, heat shock, and osmotic shock. The MAP kinase family consists of four major subfamilies of related proteins (extracellular regulated kinases 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK), p38, and extracellular regulated kinase 5 (ERK5)) and regulates numerous cellular activities, such as apoptosis, gene expression, mitosis, differentiation, and immune responses. The deregulation of these kinases is shown to be involved in human diseases, such as cancer, immune diseases, inflammation, and neurodegenerative disorders. The awareness of the therapeutic potential of the inhibition of MAP kinases led to a thorough search for small-molecule inhibitors. Here, we discuss some of the most well-known MAP kinase inhibitors and their use in cancer research.

Molecular modeling and structure-based drug discovery approach reveals protein kinases as off-targets for novel anticancer drug RH1.

Potential drug target identification and mechanism of action is an important step in drug discovery process, which can be achieved by biochemical methods, genetic interactions or computational conjectures. Sometimes more than one approach is implemented to mine out the potential drug target and characterize the on-target or off-target effects. A novel anticancer agent RH1 is designed as pro-drug to be activated by NQO1, an enzyme overexpressed in many types of tumors. However, increasing data show that RH1 can affect cells in NQO1-independent fashion. Here, we implemented the bioinformatics approach of modeling and molecular docking for search of RH1 targets among protein kinase species. We have examined 129 protein kinases in total where 96 protein kinases are in complexes with their inhibitor, 11 kinases were in the unbound state with any ligand and for 22 protein kinases 3D structure were modeled. Comparison of calculated free energy of binding of RH1 with indigenous kinase inhibitors binding efficiency as well as alignment of their pharmacophoric maps let us predict and ranked protein kinases such as KIT, CDK2, CDK6, MAPK1, NEK2 and others as the most prominent off-targets of RH1. Our finding opens new avenues in search of protein targets that might be responsible for curing cancer by new promising drug RH1 in NQO1-independent way.

KRAS, TP53, CDKN2A, SMAD4, BRCA1, and BRCA2 Mutations in Pancreatic Cancer.

Pancreatic cancer is a disease that has a very high fatality rate and one of the highest mortality ratios among all major cancers, remaining the fourth leading cause of cancer-related deaths in developed countries. The major treatment of pancreatic cancer is surgery; however, only 15-20% of patients are candidates for it at the diagnosis of disease. On the other hand, survival in patients, who undergo surgery, is less than 30%. In most cancers, genome stability is disturbed and pancreatic cancer is not the exception. Approximately 97% of pancreatic cancers have gene derangements, defined by point mutations, amplifications, deletions, translocations, and inversions. This review describes the most frequent genetic alterations found in pancreatic cancer.

The expression of cancer stem cell markers in human colorectal carcinoma cells in a microenvironment dependent manner.

Numerous lines of evidence support the hierarchical model of cancer development and tumor initiation. According to the theory, cancer stem cells play a crucial role in the formation of the tumor and should be targeted for more effective anticancer treatment. However, cancer stem cells quickly loose their characteristics when propagated as 2D cell culture, indicating that the 2D cell culture does not provide the appropriate settings to maintain an in vivo environment. In this study we have investigated the expression of self-renewal, cancer stem cell and epithelial to mesenchymal transition markers after the transfer of human colorectal carcinoma cell DLD1 and HT29 lines from 2D cell cultures to scaffold-attached laminin rich extracellular matrix and scaffold-free multicellular spheroid 3D culture models. Based on the up-regulated expression of multipotency, CSC and EMT markers, our data suggests that human colorectal carcinoma cells grown in 3D exhibit enhanced cancer stem cell characteristics. Therefore, in order to design more efficient targeted therapies, we suggest that 3D cell culture models should be employed in cancer stem cell research.

KRAS, NRAS and BRAF mutations in colorectal cancer and melanoma.

Cancers are the group of diseases, which arise because of the uncontrolled behavior of some of the genes in our cells. There are possibilities of gene amplifications, overexpressions, deletions and other anomalies which might lead to the development and spread of cancer. One of the most dangerous ways to the cancers is the mutations of the genes. The mutated genes can start unstoppable proliferation of cells, their uncontrolled motility, protection from apoptosis, the DNA mutation enhancement as well as other anomalies, leading to the cancer. This review focuses on the genes, which are frequently mutated in various cancers and are known to be important in the advance and progression of colorectal cancer and melanoma, namely KRAS, NRAS and BRAF.

Metabolomics in pancreatic cancer biomarkers research.

Pancreatic cancer is one of the worst prognoses of all malignancies. More than 40,000 deaths a year from this disease are observed in European Union alone. The only possibly curative treatment of pancreatic cancer is surgery, yet only 15-20% of patients have operable disease and even patients, which go through surgery and adjuvant chemotherapy, survival is less than 30%. The sensitive and specific biomarkers which could be used for the advance of early diagnostics are needed and constantly researched. Metabolomics is a technology which analyzes the concentrations of low-molecular-weight metabolites (the metabolome) has lately effectively developed due to the improvements in analytical technology. Metabolome analysis can be a one of the useful approaches for the biomarker discovery and disease diagnosis. Here we discuss recent discoveries in the field of pancreatic cancer metabolomics as well as the most promising biomarkers for diagnostics, prognosis and prediction.

Multi-kinase inhibitors, AURKs and cancer.

Inhibitors that impact function of kinases are valuable both for the biological research as well as therapy of kinase-associated diseases, such as different cancers. There are quite a number of inhibitors, which are quite specific for certain kinases and several of them are either already approved for the cancer therapy or are in clinical studies of various phases. However, that does not mean that each single kinase inhibitor is suitable for targeted therapy. Some of them are not effective others might be toxic or fail some other criteria for the use in vivo. On the other hand, even in case of successful therapy, many responders eventually develop resistance to the inhibitors. The limitations of various single kinase inhibitors can be fought using compounds which target multiple kinases. This tactics can increase effectiveness of the inhibitors by the synergistic effect or help to diminish the likelihood of drug resistance. To date, several families of kinases are quite popular targets of the inhibition in cancers, such as tyrosine kinases, cycle-dependent kinases, mitogen-activated protein kinases, phosphoinositide 3-kinases as well as their pathway "players" and aurora kinases. Aurora kinases play an important role in the control of the mitosis and are often altered in diverse human cancers. Here, we will describe the most interesting multi-kinase inhibitors which inhibit aurora kinases among other targets and their use in preclinical and clinical cancer studies.

The Aurora kinase inhibitors in cancer research and therapy.

Compounds that affect enzymatic function of kinases are valuable for the understanding of the complex biochemical processes in cells. Aurora kinases (AURKs) play a key role in the control of the mitosis. These kinases are frequently deregulated in different human cancers: overexpression, amplifications, translocations and deletions were reported in many cancer cell lines as well as patient tissues. These findings steered a rigorous hunt for small-molecule AURK inhibitors not only for research purposes as well as for therapeutic uses. In this review, we describe a number of AURK inhibitors and their use in cancer research and/or therapy. We hope to assist researchers and clinicians in deciding which inhibitor is most appropriate for their specific purpose. The review will also provide a broad overview of the clinical studies performed with some of these inhibitors (if such studies have been performed).

Quantitative proteomic analysis of anticancer drug RH1 resistance in liver carcinoma.

Acquired resistance of tumor cells to the therapeutic treatment is a major challenge in virtually any chemotherapy. A novel anticancer agent 2,5-diaziridinyl-3-(hydroxymethyl)-6-methyl-1,4-benzoquinone (RH1) is designed to be activated by NAD(P)H: quinone oxidoreductase, an enzyme expressed at high levels in many types of tumors. Here we investigated the potential mechanisms of acquired RH1 drug resistance in cancer cells by applying high-throughput differential quantitative proteomic analysis of the newly established RH1-resistant hepatoma cell lines. Over 400 proteins display significantly altered levels between drug-sensitive and drug-resistant cell lines. Differentially expressed proteins were clustered into more than 14 groups according to their functional annotation and protein-protein interactions. Bioinformatic analysis highlights the biological processes that might be responsible for acquired resistance to RH1. The level of several xenobiotic metabolism enzymes (total n=17) involved in RH1 activation and detoxification is decreased (Nqo1, catalase, Gst, Gsr), corresponding with the decrease in their catalytic activity. The altered biological processes also include the decrease of cell cycle positive regulators (n=15) and the increase of DNA repair proteins (n=5) as well as annexin family members (n=5) in the RH1-resistant cells. Drug-resistant hepatoma cell proteomes are also distinguished by the altered level of proteins involved in energy production and metabolism (n=55). Our data provide the basis for in-depth study of molecular mechanisms of tumor cell resistance to the promising anticancer drug RH1 enabling the further validation of protein biomarkers for the drug insusceptibility and of potential secondary pharmacological targets of RH1 resistant cells.

Roscovitine in cancer and other diseases.

Roscovitine [CY-202, (R)-Roscovitine, Seliciclib] is a small molecule that inhibits cyclin-dependent kinases (CDKs) through direct competition at the ATP-binding site. It is a broad-range purine inhibitor, which inhibits CDK1, CDK2, CDK5 and CDK7, but is a poor inhibitor for CDK4 and CDK6. Roscovitine is widely used as a biological tool in cell cycle, cancer, apoptosis and neurobiology studies. Moreover, it is currently evaluated as a potential drug to treat cancers, neurodegenerative diseases, inflammation, viral infections, polycystic kidney disease and glomerulonephritis. This review focuses on the use of roscovitine in the disease model as well as clinical model research.

Highlights of the Latest Advances in Research on CDK Inhibitors.

Uncontrolled proliferation is the hallmark of cancer and other proliferative disorders and abnormal cell cycle regulation is, therefore, common in these diseases. Cyclin-dependent kinases (CDKs) play a crucial role in the control of the cell cycle and proliferation. These kinases are frequently deregulated in various cancers, viral infections, neurodegenerative diseases, ischemia and some proliferative disorders. This led to a rigorous pursuit for small-molecule CDK inhibitors for therapeutic uses. Early efforts to block CDKs with nonselective CDK inhibitors led to little specificity and efficacy but apparent toxicity, but the recent advance of selective CDK inhibitors allowed the first successful efforts to target these kinases for the therapies of several diseases. Major ongoing efforts are to develop CDK inhibitors as monotherapies and rational combinations with chemotherapy and other targeted drugs.

The CDK inhibitors in cancer research and therapy.

Chemical compounds that interfere with an enzymatic function of kinases are useful for gaining insight into the complicated biochemical processes in mammalian cells. Cyclin-dependent kinases (CDK) play an essential role in the control of the cell cycle and/or proliferation. These kinases as well as their regulators are frequently deregulated in different human tumors. Aberrations in CDK activity have also been observed in viral infections, Alzheimer's, Parkinson's diseases, ischemia and some proliferative disorders. This led to an intensive search for small-molecule CDK inhibitors not only for research purposes, but also for therapeutic applications. Here, we discuss seventeen CDK inhibitors and their use in cancer research or therapy. This review should help researchers to decide which inhibitor is best suited for the specific purpose of their research. For this purpose, the targets, commercial availability and IC(50) values are provided for each inhibitor. The review will also provide an overview of the clinical studies performed with some of these inhibitors.