Inhibition of Akt with small molecules and biologics: historical perspective and current status of the patent landscape

Treatment-related adverse events in patients with advanced breast cancer receiving adjuvant AKT inhibitors: a meta-analysis of randomized controlled trials

INTRODUCTION

Incorporation of AKT inhibitors into adjuvant therapy for advanced or metastatic breast cancer has improved clinical outcomes. However, the safety of AKT inhibitors should be better evaluated, given the possibility of prolonging survival and impacting patient quality of life. Our aim was to assess how the addition of AKT inhibitors to adjuvant therapy affects treatment-related adverse events.

METHODS

We evaluated binary outcomes with risk ratios (RRs), with 95% confidence intervals (CIs). We used DerSimonian and Laird random-effect models for all endpoints. Heterogeneity was assessed using I2 statistics. R, version 4.2.3, was used for statistical analyses.

RESULTS

A total of seven RCTs comprising 1619 patients with BC. The adverse effects that show significance statistical favoring the occurrence of adverse effects in AKT inhibitor were diarrhea (RR 3.05; 95% CI 2.48-3.75; p < 0.00001; I2 = 49%), hyperglycemia (RR 3.4; 95% CI 1.69-6.83; p = 0.00058; I2 = 75%), nausea (RR 1.69; 95% CI 1.34-2.13; p = 0.000008; I2 = 42%), rash (RR 2.79; 95% CI 1.49-5.23; p = 0.0013; I2 = 82%), stomatitis (RR 2.24; 95% CI 1.69-2.97; p < 0.00001; I2 = 16%) and vomiting (RR 2.99; 95% CI 1.85-4.86; p = 0.00009; I2 = 42%). There was no significant difference between the groups for alopecia (p = 0.80), fatigue (p = 0.087), and neuropathy (p = 0.363380).

CONCLUSION

The addition of AKT inhibitors to adjuvant therapy was associated with an increase in treatment-related adverse events. These results provide safety information for further clinical trials evaluating AKT inhibitor therapy for patients with metastatic BC. Clinicians should closely monitor patients for treatment-related adverse events to avoid discontinuation of therapy and morbidity caused by these early-stage therapies.

Targeting SMAD-Dependent Signaling: Considerations in Epithelial and Mesenchymal Solid Tumors

SMADs are the canonical intracellular effector proteins of the TGF-β (transforming growth factor-β). SMADs translocate from plasma membrane receptors to the nucleus regulated by many SMAD-interacting proteins through phosphorylation and other post-translational modifications that govern their nucleocytoplasmic shuttling and subsequent transcriptional activity. The signaling pathway of TGF-β/SMAD exhibits both tumor-suppressing and tumor-promoting phenotypes in epithelial-derived solid tumors. Collectively, the pleiotropic nature of TGF-β/SMAD signaling presents significant challenges for the development of effective cancer therapies. Here, we review preclinical studies that evaluate the efficacy of inhibitors targeting major SMAD-regulating and/or -interacting proteins, particularly enzymes that may play important roles in epithelial or mesenchymal compartments within solid tumors.

Identification of allosteric inhibitor against AKT1 through structure-based virtual screening

AKT (serine/threonine protein kinase) is a potential therapeutic target for many types of cancer as it plays a vital role in cancer progression. Many AKT inhibitors are already in practice under single and combinatorial therapy. However, most of these inhibitors are orthosteric / pan-AKT that are non-selective and non-specific to AKT kinase and their isoforms. Hence, researchers are searching for novel allosteric inhibitors that bind in the interface between pH and kinase domain. In this study, we performed structure-based virtual screening from the afroDB (a diverse natural compounds library) to find the potential inhibitor targeting the AKT1. These compounds were filtered through Lipinski, ADMET properties, combined with a molecular docking approach to obtain the 8 best compounds. Then we performed molecular dynamics simulation for apoprotein, AKT1 with 8 complexes, and AKT1 with the positive control (Miransertib). Molecular docking and simulation analysis revealed that Bianthracene III (hit 1), 10-acetonyl Knipholonecyclooxanthrone (hit 2), Abyssinoflavanone VII (hit 5) and 8-c-p-hydroxybenzyldiosmetin (hit 6) had a better binding affinity, stability, and compactness than the reference compound. Notably, hit 1, hit 2 and hit 5 had molecular features required for allosteric inhibition.

Computer-Aided Identification of Kinase-Targeted Small Molecules for Cancer: A Review on AKT Protein

AKT (also known as PKB) is a serine/threonine kinase that plays a pivotal regulatory role in the PI3K/AKT/mTOR signaling pathway. Dysregulation of AKT activity, especially its hyperactivation, is closely associated with the development of various human cancers and resistance to chemotherapy. Over the years, a wide array of AKT inhibitors has been discovered through experimental and computational approaches. In this regard, herein we present a comprehensive overview of AKT inhibitors identified using computer-assisted drug design methodologies (including docking-based and pharmacophore-based virtual screening, machine learning, and quantitative structure-activity relationships) and successfully validated small molecules endowed with anticancer activity. Thus, this review provides valuable insights to support scientists focused on AKT inhibition for cancer treatment and suggests untapped directions for future computer-aided drug discovery efforts.

An updated patent review of AKT inhibitors (2020 - present)

INTRODUCTION

Protein kinase B (Akt), an essential protein in the PI3K/Akt/mTOR signaling pathway, plays a crucial role in tumor progression. Over the past two years, different types of Akt modulators have continued to emerge in the patent literature.

AREAS COVERED

This review focuses on the patent literature covering small molecule inhibitors, peptides, PROTACs, and antisense nucleic acids targetingAkt from 2020 to present. Also, we discuss the outcomes of several clinical trials, combination strategies for different mechanisms, and the application of Akt regulators in other non-oncology indications.Our search for relevant information was conducted using various databases, including the European Patent Office, SciFinder, andPubMed, from 01.2020 to 04.2023.

EXPERT OPINION

In recent years, some combination therapeutic strategies involvingAkt inhibitors have shown promising clinical outcomes. Future research can be directed toward developing new applications of Akt inhibitors, which may have implications for other diseases beyond cancer. New attempts suggest that targeting allosteric sites may be a potential solution to the problem of isoform selectivity.Furthermore, directly knocking out Akt protein by using the degraderssuggests a promising direction for future development.

A Meroterpenoid from Tibetan Medicine Induces Lung Cancer Cells Apoptosis through ROS-Mediated Inactivation of the AKT Pathway

As a traditional Tibetan medicine in China, Meconopsis grandis Prain has been used to treat a variety of illnesses by local people for thousands of years. However, the active ingredients contained in Meconopsis grandis Prain and its pharmacodynamic mechanisms have scarcely been reported. We isolated a meroterpenoid named D1399 from Meconopsis grandis Prain endophytic fungi with strong antitumor activity. The structure analysis showed that D1399 is an alkaloid containing a 13-membered macrocyclic structure. The IC₅₀ of D1399 for human lung cancer cells' viability ranged from 0.88 to 2.45 μM. Furthermore, we utilized TUNEL assay and western blotting to investigate the antitumor effectiveness of D1399. The results have shown that D1399 induced the apoptosis of lung cancer cells on the extrinsic and intrinsic pathways by boosting ROS generation and repressing AKT activity. In the mouse xenograft model, the average tumor weight with 30 mg·kg^-1 D1399 treatment exhibited 73.19% inhibition compared with the untreated control, without affecting body weight loss. Above all, for the first time, our study provides a possible mechanism for the antitumor activity of D1399 in vitro and in vivo as a natural product from Tibetan medicine with Meconopsis grandis Prain, which may be a potentially promising antitumor drug candidate.

Targeting Akt/PKB in pediatric tumors: A review from preclinical to clinical trials

The serine/threonine kinase Akt is a major player in the phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway, and its modulation impacts multiple cellular processes such as growth, proliferation, and survival. Several abnormalities in this pathway have been documented over the years, and these alterations were shown to have great implications in tumorigenesis and resistance to chemotherapy. Thus, multiple Akt inhibitors have been developed and tested in adult tumors, and some of them are currently undergoing phase I, II, and III clinical trials for distinct cancers that arise during adulthood. Despite that, the impact of these inhibitors is still not fully understood in pediatric tumors, and Akt-specific targeting seems to be a promising approach to treat children affected by cancers. This review summarizes recent available evidence of Akt inhibitors in pediatric cancers, from both preclinical and clinical studies. In short, we demonstrate the impact that Akt inhibition provides in tumorigenesis, and we suggest targeting the PI3K/Akt/mTOR signaling pathway, alone or in combination with other inhibitors, is a feasible tool to achieve better outcomes in pediatric tumors.

Discovery of N-((3S,4S)-4-(3,4-Difluorophenyl)piperidin-3-yl)-2-fluoro-4-(1-methyl-1H-pyrazol-5-yl)benzamide (Hu7691), a Potent and Selective Akt Inhibitor That Enables Decrease of Cutaneous Toxicity

Rash is one of the primary dose-limiting toxicities of Akt (protein kinase B) inhibitors in clinical trials. Here, we demonstrate the inhibition of Akt2 isozyme may be a driver for keratinocyte apoptosis, which promotes us to search for new selective Akt inhibitors with an improved cutaneous safety property. According to our previous research, compound 2 is selected for further optimization for overcoming the disadvantages of compound 1, including high Akt2 inhibition and high toxicity against HaCaT keratinocytes. The dihedral angle-based design and molecular dynamics simulation lead to the identification of Hu7691 (B5) that achieves a 24-fold selectivity between Akt1 and Akt2. Hu7691 exhibits low activity in inducing HaCaT apoptosis, promising kinase selectivity, and excellent anticancer cell proliferation potencies. Based on the superior results of safety property, pharmacokinetic profile, and in vivo efficacy, the National Medical Products Administration (NMPA) approved the investigational new drug (IND) application of Hu7691.

Norcycloartocarpin targets Akt and suppresses Akt-dependent survival and epithelial-mesenchymal transition in lung cancer cells

In searching for novel targeted therapeutic agents for lung cancer treatment, norcycloartocarpin from Artocarpus gomezianus was reported in this study to promisingly interacted with Akt and exerted the apoptosis induction and epithelial-to-mesenchymal transition suppression. Selective cytotoxic profile of norcycloartocarpin was evidenced with approximately 2-fold higher IC50 in normal dermal papilla cells (DPCs) compared with human lung cancer A549, H460, H23, and H292 cells. We found that norcycloartocarpin suppressed anchorage-independent growth, cell migration, invasion, filopodia formation, and decreased EMT in a dose-dependent manner at 24 h, which were correlated with reduced protein levels of N-cadherin, Vimentin, Slug, p-FAK, p-Akt, as well as Cdc42. In addition, norcycloartocarpin activated apoptosis caspase cascade associating with restoration of p53, down-regulated Bcl-2 and augmented Bax in A549 and H460 cells. Interestingly, norcycloartocarpin showed potential inhibitory role on protein kinase B (Akt) the up-stream dominant molecule controlling EMT and apoptosis. Computational molecular docking analysis further confirmed that norcycloartocarpin has the best binding affinity of -12.52 kcal/mol with Akt protein at its critical active site. As Akt has recently recognized as an attractive molecular target for therapeutic approaches, these findings support its use as a plant-derived anticancer agent in cancer therapy.

Biological Role of AKT and Regulation of AKT Signaling Pathway by Thymoquinone: Perspectives in Cancer Therapeutics

BACKGROUND

AKT/PKB is an important enzyme with numerous biological functions, and its overexpression is related to carcinogenesis. AKT stimulates different signaling pathways that are downstream of activated tyrosine kinases and phosphatidylinositol 3-kinase, hence functions as an important target for anti-cancer drugs.

OBJECTIVE

In this review article, we have interpreted the role of AKT signaling pathway in cancer and the natural inhibitory effect of Thymoquinone (TQ) in AKT and its possible mechanisms.

METHOD

We have collected the updated information and data on AKT, its role in cancer and the inhibitory effect of TQ in AKT signaling pathway from Google Scholar, PubMed, Web of Science, Elsevier, Scopus, and many more.

RESULTS

Many drugs are already developed, which can target AKT, but very few among them have passed clinical trials. TQ is a natural compound, mainly found in black cumin, which has been found to have potential anti-cancer activities. TQ targets numerous signaling pathways, including AKT, in different cancers. In fact, many studies revealed that AKT is one of the major targets of TQ. The preclinical success of TQ suggests its clinical studies on cancer.

CONCLUSION

This review article summarizes the role of AKT in carcinogenesis, its potent inhibitors in clinical trials, and how TQ acts as an inhibitor of AKT and TQ's future as a cancer therapeutic drug.

Activation of GSK3 Prevents Termination of TNF-Induced Signaling

Background

Termination of TNF-induced signaling plays a key role in the resolution of inflammation with dysregulations leading to severe pathophysiological conditions (sepsis, chronic inflammatory disease, cancer). Since a recent phospho-proteome analysis in human monocytes suggested GSK3 as a relevant kinase during signal termination, we aimed at further elucidating its role in this context.

Materials and Methods

For the analyses, THP-1 monocytic cells and primary human monocytes were used. Staurosporine (Stauro) was applied to activate GSK3 by inhibiting kinases that mediate inhibitory GSK3α/β-Ser21/9 phosphorylation (eg, PKC). For GSK3 inhibition, Kenpaulone (Ken) was used. GSK3- and PKC-siRNAs were applied for knockdown experiments. Protein expression and phosphorylation were assessed by Western blot or ELISA and mRNA expression by qPCR. NF-κB activation was addressed using reporter gene assays.

Results

Constitutive GSK3β and PKCβ expression and GSK3α/β-Ser21/9 and PKCα/βII-Thr638/641 phosphorylation were not altered during TNF long-term incubation. Stauro-induced GSK3 activation (demonstrated by Bcl3 reduction) prevented termination of TNF-induced signaling as reflected by strongly elevated IL-8 expression (used as an indicator) following TNF long-term incubation. A similar increase was observed in TNF short-term-exposed cells, and this effect was inhibited by Ken. PKCα/β-knockdown modestly increased, whereas GSK3α/β-knockdown inhibited TNF-induced IL-8 expression. TNF-dependent activation of two NF-κB-dependent indicator plasmids was enhanced by Stauro, demonstrating transcriptional effects. A TNF-induced increase in p65-Ser536 phosphorylation was further enhanced by Stauro, whereas IκBα proteolysis and IKKα/β-Ser176/180 phosphorylation were not affected. Moreover, PKCβ-knockdown reduced levels of Bcl3. A20 and IκBα mRNA, both coding for signaling inhibitors, were dramatically less affected under our conditions when compared to IL-8, suggesting differential transcriptional effects.

Conclusion

Our results suggest that GSK3 activation is involved in preventing the termination of TNF-induced signaling. Our data demonstrate that activation of GSK3 – either pathophysiologically or pharmacologically induced – may destroy the finely balanced condition necessary for the termination of inflammation-associated signaling.

An updated patent review of Akt inhibitors (2016-present)

Introduction: Akt is a widely known serine threonine kinase involved in a series of critical cellular pathways like cell survival and proliferation. With the development of small-molecule Akt inhibitors, new strategies such as covalent, peptide-based, and PROTAC (Proteolysis Targeting Chimera) strategies have also been used the design of Akt inhibitors. On the other hand, due to the specificity of the Akt pathway, the use of Akt modulators in combination therapy and immunotherapy has been disclosed in the past 5 years.Areas covered: This review focuses on the patent literature covering small-molecule inhibitors of Akt kinase and their applications from 2016-present.Expert opinion: Although Akt inhibitors' progress has been somewhat slow over the past five years, new strategies still provide new opportunities for the development of Akt inhibitors. Combination with Akt pathway inhibitors for tumor therapy has also been widely disclosed in patents in the last 5 years. Notably, combination strategies of Akt inhibitors and immunotherapy have started to emerge in recent years. While the clinical indications of Akt modulators should not be limited to anti-cancer, it is still worth trying the treatment of other diseases. Within the next years, current drug development around Akt inhibitors should be fascinating.

Phospho-Form Specific Substrates of Protein Kinase B (AKT1)

Protein kinase B (AKT1) is hyper-activated in diverse human tumors. AKT1 is activated by phosphorylation at two key regulatory sites, Thr308 and Ser473. Active AKT1 phosphorylates many, perhaps hundreds, of downstream cellular targets in the cytosol and nucleus. AKT1 is well-known for phosphorylating proteins that regulate cell survival and apoptosis, however, the full catalog of AKT1 substrates remains unknown. Using peptide arrays, we recently discovered that each phosphorylated form of AKT1 (pAKT1^S473, pAKT1^T308, and ppAKT1^S473,T308) has a distinct substrate specificity, and these data were used to predict potential new AKT1 substrates. To test the high-confidence predictions, we synthesized target peptides representing putative AKT1 substrates. Peptides substrates were synthesized by solid phase synthesis and their purity was confirmed by mass spectrometry. Most of the predicted peptides showed phosphate accepting activity similar to or greater than that observed with a peptide derived from a well-established AKT1 substrate, glycogen synthase kinase 3β (GSK-3β). Among the novel substrates, AKT1 was most active with peptides representing PIP3-binding protein Rab11 family-interacting protein 2 and cysteinyl leukotriene receptor 1, indicating their potential role in AKT1-dependent cellular signaling. The ppAKT1^S473,T308 enzyme was highly selective for peptides containing a patch of basic residues at −5, −4, −3 and aromatic residues (Phe/Tyr) at +1 positions from the phosphorylation site. The pAKT1^S473 variant preferred more acidic peptides, Ser or Pro at +4, and was agnostic to the residue at −5. The data further support our hypothesis that Ser473 phosphorylation plays a key role in modulating AKT1 substrate selectivity.

Akt isoform-specific effects on thyroid cancer development and progression in a murine thyroid cancer model

The Akt family is comprised of three unique homologous proteins with isoform-specific effects, but isoform-specific in vivo data are limited in follicular thyroid cancer (FTC), a PI3 kinase-driven tumor. Prior studies demonstrated that PI3K/Akt signaling is important in thyroid hormone receptor βPV/PV knock-in (PV) mice that develop metastatic thyroid cancer that most closely resembles FTC. To determine the roles of Akt isoforms in this model we crossed Akt1-/-, Akt2-/-, and Akt3-/- mice with PV mice. Over 12 months, thyroid size was reduced for the Akt null crosses (p < 0.001). Thyroid cancer development and local invasion were delayed in only the PVPV-Akt1 knock out (KO) mice in association with increased apoptosis with no change in proliferation. Primary-cultured PVPV-Akt1KO thyrocytes uniquely displayed a reduced cell motility. In contrast, loss of any Akt isoform reduced lung metastasis while vascular invasion was reduced with Akt1 or 3 loss. Microarray of thyroid RNA displayed incomplete overlap between the Akt KO models. The most upregulated gene was the dendritic cell (DC) marker CD209a only in PVPV-Akt1KO thyroids. Immunohistochemistry demonstrated an increase in CD209a-expressing cells in the PVPV-Akt1KO thyroids. In summary, Akt isoforms exhibit common and differential functions that regulate local and metastatic progression in this model of thyroid cancer.

Th1 cytokines in conjunction with pharmacological Akt inhibition potentiate apoptosis of breast cancer cells in vitro and suppress tumor growth in vivo

Targeted drug approaches have been a major focus for developing new anticancer therapies. Although many such agents approved in the last 20 years have improved outcomes, almost all have underperformed expectations. The full potential of such agents may yet be obtained through novel combinations. Previously, we showed that anti-estrogen drugs combined with a dendritic cell-based anti-HER-2 vaccine known to induce strong Th1-polarized immunity dramatically improved clinical response rates in patients with HER-2^pos/ER^pos early breast cancer. Here, we show that the small molecule Akt antagonist MK-2206, when combined with the Th1 cytokines IFN-gamma and TNF-alpha, maximize indicators of apoptotic cell death in a panel of phenotypically-diverse human breast cancer lines. These findings were mirrored by other, structurally-unrelated Akt-targeting drugs that work through different mechanisms. Interestingly, we found that MK-2206, as well as the other Akt antagonist drugs, also had a tendency to suppress Th1 cytokine expression in stimulated human and murine lymphocytes, potentially complicating their use in conjunction with active immunotherapy. After verifying that MK-2206 plus IFN-gamma could show similar combined effects against breast cancer lines, even in the absence of TNF-alpha, we tested in a rodent HER-2^pos breast cancer model either a HER-2-based DC vaccine, or recombinant IFN-gamma with or without MK-2206 administration. We found that for MK-2206, co-administration of recombinant IFN-gamma outperformed co-administration of DC vaccination for slowing tumor growth kinetics. These findings suggest a combined therapy approach for Akt-targeting drugs that incorporates recombinant Interferon-gamma and is potentially translatable to humans.

In Silico Screening Anticancer of Six Triterpenoids toward miR-494 and TNF-α Targets

Hepatocellular carcinoma (HCC) accounts for up to 90% of all primary liver cancers worldwide. Cinobufagin is recognized to inhibit miR-494 as the HCC target. Increased expression of TNF-α results in an inadequate response to liver anticancer drugs. The models in this study were cinobufagin, cycloartenol, and ethyl acetate fractions of Ganoderma lucidum, 2–5. Seven docking targets in this study were Akt, ERK1, ERK2, PI3K, TNF-α, TNFR1, and TNFR2. Cycloartenol and compound 4 comply with Veber’s rules, Lipinski’s rule of 5, and demonstrate moderate toxicity. The action implies a potential docking target since it produces bond affinities with the compound 2–5 that agree with the IC50 in the literature, which is based on in vitro experiments. Akt as a receptor target is AZD5363. Cycloartenol shows a low ability to inhibit Akt. Conversely, compound 4 inhibits the Akt better than that of cycloartenol, although it is not as good as cinobufagin and AZD5363. Therefore, compound 4, a triterpenoid with a basic framework of lanostane has the potential to be an anticancer candidate for the liver.

Apoptosis of cancer cells is triggered by selective crosslinking and inhibition of receptor tyrosine kinases

Receptor tyrosine kinases (RTK) have been the most prevalent therapeutic targets in anti-cancer drug development. However, the emergence of drug resistance toward single target RTK inhibitors remains a major challenge to achieve long-term remissions. Development of alternative RTK inhibitory strategies that bypass drug resistance is much wanted. In the present study, we found that selected cell surface RTKs were inhibited and crosslinked into detergent resistant complexes by oligomeric but not monomeric concanavalin A (ConA). The inhibition of RTKs by ConA led to suppression of pro-survival pathways and induction of apoptosis in multiple cancer cell lines, while overexpression of constitutively activated protein kinase B (AKT) reversed the apoptotic effect. However, major cell stress sensing checkpoints were not influenced by ConA. To our knowledge, selective crosslinking and inhibition of cell surface receptors by ConA-like molecules might represent a previously unidentified mechanism that could be potentially exploited for therapeutic development.

The Akt pathway in oncology therapy and beyond (Review)

Protein kinase B (Akt), similar to many other protein kinases, is at the crossroads of cell death and survival, playing a pivotal role in multiple interconnected cell signaling mechanisms implicated in cell metabolism, growth and division, apoptosis suppression and angiogenesis. Akt protein kinase displays important metabolic effects, among which are glucose uptake in muscle and fat cells or the suppression of neuronal cell death. Disruptions in the Akt-regulated pathways are associated with cancer, diabetes, cardiovascular and neurological diseases. The regulation of the Akt signaling pathway renders Akt a valuable therapeutic target. The discovery process of Akt inhibitors using various strategies has led to the identification of inhibitors with great selectivity, low side-effects and toxicity. The usefulness of Akt emerges beyond cancer therapy and extends to other major diseases, such as diabetes, heart diseases, or neurodegeneration. This review presents key features of Akt structure and functions, and presents the progress of Akt inhibitors in regards to drug development, and their preclinical and clinical activity in regards to therapeutic efficacy and safety for patients.

The next generation of PI3K-Akt-mTOR pathway inhibitors in breast cancer cohorts

The PI3K/Akt/mTOR pathway plays a role in various oncogenic processes in breast cancer and key pathway aberrations have been identified which drive the different molecular subtypes. Early drugs developed targeting this pathway produced some clinical success but were hampered by pharmacokinetics, tolerability and efficacy problems. This created a need for new PI3K pathway-inhibiting drugs, which would produce more robust results allowing incorporation into treatment regimens for breast cancer patients. In this review, the most promising candidates from the new generation of PI3K-pathway inhibitors is explored, presenting evidence from preclinical and early clinical research, as well as ongoing trials utilising these drugs in breast cancer cohorts. The problems hindering the development of drugs targeting the PI3K pathway are examined, which have created problems for their use as monotherapies. PI3K pathway inhibitor combinations therefore remains a dynamic research area, and their role in combination with immunotherapies and epigenetic therapies is also inspected.

Discovery of chiral dihydropyridopyrimidinones as potent, selective and orally bioavailable inhibitors of AKT

During the course of our research efforts to develop potent and selective AKT inhibitors, we discovered enatiomerically pure substituted dihydropyridopyrimidinones (DHP) as potent inhibitors of protein kinase B/AKT with excellent selectivity against ROCK₂. A key challenge in this program was the poor physicochemical properties of the initial lead compound 5. Integration of structure-based drug design and physical properties-based design resulted in replacement of a highly hydrophobic poly fluorinated aryl ring by a simple trifluoromethyl that led to identification of compound 6 with much improved physicochemical properties. Subsequent SAR studies led to the synthesis of new pyran analog 7 with improved cell potency. Further optimization of pharmacokintetics properties by increasing permeability with appropriate fluorinated alkyl led to compound 8 as a potent, selective AKT inhibitors that blocks the phosphorylation of GSK3β in vivo and had robust, dose and concentration dependent efficacy in the U87MG tumor xenograft model.

AGC kinases, mechanisms of regulation ‎and innovative drug development

The group of AGC kinases consists of 63 evolutionarily related serine/threonine protein kinases comprising PDK1, PKB/Akt, SGK, PKC, PRK/PKN, MSK, RSK, S6K, PKA, PKG, DMPK, MRCK, ROCK, NDR, LATS, CRIK, MAST, GRK, Sgk494, and YANK, while two other families, Aurora and PLK, are the most closely related to the group. Eight of these families are physiologically activated downstream of growth factor signalling, while other AGC kinases are downstream effectors of a wide range of signals. The different AGC kinase families share aspects of their mechanisms of inhibition and activation. In the present review, we update the knowledge of the mechanisms of regulation of different AGC kinases. The conformation of the catalytic domain of many AGC kinases is regulated allosterically through the modulation of the conformation of a regulatory site on the small lobe of the kinase domain, the PIF-pocket. The PIF-pocket acts like an ON-OFF switch in AGC kinases with different modes of regulation, i.e. PDK1, PKB/Akt, LATS and Aurora kinases. In this review, we make emphasis on how the knowledge of the molecular mechanisms of regulation can guide the discovery and development of small allosteric modulators. Molecular probes stabilizing the PIF-pocket in the active conformation are activators, while compounds stabilizing the disrupted site are allosteric inhibitors. One challenge for the rational development of allosteric modulators is the lack of complete structural information of the inhibited forms of full-length AGC kinases. On the other hand, we suggest that the available information derived from molecular biology and biochemical studies can already guide screening strategies for the identification of innovative mode of action molecular probes and the development of selective allosteric drugs for the treatment of human diseases.

Akt inhibitors in cancer treatment: The long journey from drug discovery to clinical use (Review)

Targeted cancer therapies are used to inhibit the growth, progression, and metastasis of the tumor by interfering with specific molecular targets and are currently the focus of anticancer drug development. Protein kinase B, also known as Akt, plays a central role in many types of cancer and has been validated as a therapeutic target nearly two decades ago. This review summarizes the intracellular functions of Akt as a pivotal point of converging signaling pathways involved in cell growth, proliferation, apoptotis and neo‑angiogenesis, and focuses on the drug design strategies to develop potent anticancer agents targeting Akt. The discovery process of Akt inhibitors has evolved from adenosine triphosphate (ATP)‑competitive agents to alternative approaches employing allosteric sites in order to overcome the high degree of structural similarity between Akt isoforms in the catalytic domain, and considerable structural analogy to the AGC kinase family. This process has led to the discovery of inhibitors with greater specificity, reduced side-effects and lower toxicity. A second generation of Akt has inhibitors emerged by incorporating a chemically reactive Michael acceptor template to target the nucleophile cysteines in the catalytic activation loop. The review outlines the development of several promising drug candidates emphasizing the importance of each chemical scaffold. We explore the pipeline of Akt inhibitors and their preclinical and clinical examination status, presenting the potential clinical application of these agents as a monotherapy or in combination with ionizing radiation, other targeted therapies, or chemotherapy.

IPAT: a freely accessible software tool for analyzing multiple patent documents with inbuilt landscape visualizer

Intelligent Patent Analysis Tool (IPAT) is an online data retrieval tool, operated based on text mining algorithm to extract specific patent information in a predetermined pattern into an Excel sheet. The software is designed and developed to retrieve and analyze technology information from multiple patent documents and generate various patent landscape graphs and charts. The software is C# coded in visual studio 2010, which extracts the publicly available patent information from the web pages like Google Patent and simultaneously study the various technology trends based on user-defined parameters. In other words, IPAT combined with the manual categorization will act as an excellent technology assessment tool in competitive intelligence and due diligence for predicting the future R&D forecast.

Mutant PIK3CA controls DUSP1-dependent ERK 1/2 activity to confer response to AKT target therapy

Background:

Alterations in the phosphoinositide 3-kinase/AKT/mammalian target of rapamycin (PI3K/AKT/mTOR) signalling pathway are frequent in urothelial bladder cancer (BLCA) and thus provide a potential target for novel therapeutic strategies. We investigated the efficacy of the AKT inhibitor MK-2206 in BLCA and the molecular determinants that predict therapy response.

Methods:

Biochemical and functional effects of the AKT inhibitor MK-2206 were analysed on a panel of 11 BLCA cell lines possessing different genetic alterations. Cell viability (CellTiter-Blue, cell counts), apoptosis (caspase 3/7 activity) and cell cycle progression (EdU incorporation) were analysed to determine effects on cell growth and proliferation. cDNA or siRNA transfections were used to manipulate the expression of specific proteins such as wild-type or mutant PIK3CA, DUSP1 or CREB. For in vivo analysis, the chicken chorioallantoic membrane model was utilised and tumours were characterised by weight and biochemically for the expression of Ki-67 and AKT phosphorylation.

Results:

Treatment with MK-2206 suppressed AKT and S6K1 but not 4E-BP1 phosphorylation in all cell lines. Functionally, only cell lines bearing mutations in the hotspot helical domain of PIK3CA were sensitive to the drug, independent of other genetic alterations in the PI3K or MAPK signalling pathway. Following MK-2206 treatment, the presence of mutant PIK3CA resulted in an increase in DUSP1 expression that induced a decrease in ERK 1/2 phosphorylation. Manipulating the expression of mutant or wild-type PIK3CA or DUSP1 confirmed that this mechanism is responsible for the induction of apoptosis and the inhibition of tumour proliferation in vitro and in vivo, to sensitise cells to AKT target therapy.

Conclusion or interpretation:

PIK3CA mutations confer sensitivity to AKT target therapy in BLCA by regulating DUSP1 expression and subsequent ERK1/2 dephosphorylation and can potentially serve as a stratifying biomarker for treatment.

Clearing the fog of anticancer patents from 1993-2013: through an in-depth technology landscape & target analysis from pioneer research institutes and universities worldwide

BACKGROUND

In a search for an effective anticancer therapy the R&D units from leading universities and institutes reveal numerous technologies in the form of patent documents. The article addressed comparative anticancer patent landscape and technology assessment of Council of Scientific and Industrial Research (CSIR): India's largest R&D organisation with top twenty international public funded universities and institutes from eight different countries.

METHODOLOGY/PRINCIPAL FINDINGS

The methodology include quantitative and qualitative assessment based on the bibliometric parameters and manual technology categorisation to understand the changing patent trends and recent novel technologies. The research finding analysed 25,254 patent documents from the year 1993 to 2013 and reported the insights of latest anticancer technologies and targets through categorisation studies at the level of drug discovery, development and treatment & diagnosis. The article has reported the technology correlation matrix of twelve secondary class technologies with 34 tertiary sub-class research area to identify the leading technologies and scope of future research through whitespaces analysis. In addition, the results have also addressed the target analysis, leading inventor, assignee, collaboration network, geographical distribution, patent trend analysis, citation maps and technology assessment with respect to international patent classification systems such as CPC, IPC and CPI codes.

CONCLUSIONS/SIGNIFICANCE

The result suggested peptide technology as the dominating research area next to gene therapy, vaccine and medical preparation containing organic compounds. The Indian CSIR has ranked itself at seventh position among the top 20 universities. Globally, the anticancer research was focused in the area of genetics and immunology, whereas Indian CSIR reported more patents related to plant extract and organic preparation. The article provided a glimpse of two decade anticancer scenario with respect to top public funded universities worldwide.

Anticancer patent landscape and technology assessment of Indian public-funded research institutes and organizations

INTRODUCTION

This review discusses the various drug therapeutic targets and latest technologies of anticancer patents from 10 Indian public-funded research organizations covering more than 150 esteemed institutes. We have identified and reported the leading assignee and inventors along with their collaboration network and, thereby, have analyzed the various patent trends, geographical distributions, citation maps, Derwent World Patents Index, international patent classification analysis and the like.

AREAS COVERED

This article provides the insights of 1905 patent documents from 191 families and discusses in-depth anticancer technology through categorization studies at the level of drug discovery, drug development and treatment and diagnosis. In addition, various cancer targets were correlated with recent technologies so as to identify the white spaces for upcoming technologies.

EXPERT OPINION

Over a period of 13 years (1990 - 2013) the main focus of Indian cancer research was in the field of synthetic chemistry and natural extracts followed by the pharmaceutical compositions and combinations, whereas, the white spaces for future cancer remedy were identified from research in the areas of cancer stem cell lines, vaccines, gene therapy, nano formulations with targeted drug delivery systems as core and latest technologies.

Targeting protein-protein interaction by small molecules

Protein-protein interactions (PPIs) are critical regulatory events in physiology and pathology, and they represent an important target space for pharmacological intervention. However, targeting PPIs with small molecules is challenging owing to the large surface area involved in protein-protein binding and the lack of obvious small-molecule-binding pockets at many protein-protein interfaces. Nonetheless, successful examples of small-molecule modulators of PPIs have been growing in recent years. This article reviews some of the recent advances in the discovery of small-molecule regulators of PPIs that involve key oncogenic proteins. Our discussion focuses on the three key modes of action for these small-molecule modulators: orthosteric inhibition, allosteric regulation, and interfacial binding/stabilization. Understanding the opportunities and challenges of these diverse mechanisms will help guide future efforts in developing small-molecule modulators against PPIs.

Inactivation of Nuclear Factor-Y Inhibits Vascular Smooth Muscle Cell Proliferation and Neointima Formation

Objective—

Atherosclerosis and restenosis are multifactorial diseases associated with abnormal vascular smooth muscle cell (VSMC) proliferation. Nuclear factor-Y (NF-Y) plays a major role in transcriptional activation of the CYCLIN B1 gene ( CCNB1 ), a key positive regulator of cell proliferation and neointimal thickening. Here, we investigated the role of NF-Y in occlusive vascular disease.

Approach and Results—

We performed molecular and expression studies in cultured cells, animal models, and human tissues. We find upregulation of NF-Y and cyclin B1 expression in proliferative regions of murine atherosclerotic plaques and mechanically induced lesions, which correlates with higher binding of NF-Y to target sequences in the CCNB1 promoter. NF-YA expression in neointimal lesions is detected in VSMCs, macrophages, and endothelial cells. Platelet-derived growth factor-BB, a main inductor of VSMC growth and neointima development, induces the recruitment of NF-Y to the CCNB1 promoter and augments both CCNB1 mRNA expression and cell proliferation through extracellular signal–regulated kinase 1/2 and Akt activation in rat and human VSMCs. Moreover, adenovirus-mediated overexpression of a NF-YA-dominant negative mutant inhibits platelet-derived growth factor-BB–induced CCNB1 expression and VSMC proliferation in vitro and neointimal lesion formation in a mouse model of femoral artery injury. We also detect NF-Y expression and DNA-binding activity in human neointimal lesions.

Conclusions—

Our results identify NF-Y as a key downstream effector of the platelet-derived growth factor-BB–dependent mitogenic pathway that is activated in experimental and human vasculoproliferative diseases. They also identify NF-Y inhibition as a novel and attractive strategy for the local treatment of neointimal formation induced by vessel denudation.

Targeting pathological B cell receptor signalling in lymphoid malignancies

Signalling through the B cell receptor (BCR) is central to the development and maintenance of B cells. In light of the numerous proliferative and survival pathways activated downstream of the BCR, it comes as no surprise that malignant B cells would co-opt this receptor to promote their own growth and survival. However, direct evidence for BCR signalling in human lymphoma has only come to light recently. Roles for antigen-dependent and antigen-independent, or tonic, BCR signalling have now been described for several different lymphoma subtypes. Furthermore, correlative data implicate antigen-dependent BCR signalling in many other forms of lymphoma. A host of therapeutic agents targeting effectors of the BCR signalling pathway are now in clinical trials and have shown initial success against multiple forms of lymphoma.

Targeting activated Akt with GDC-0068, a novel selective Akt inhibitor that is efficacious in multiple tumor models

PURPOSE

We describe the preclinical pharmacology and antitumor activity of GDC-0068, a novel highly selective ATP-competitive pan-Akt inhibitor currently in clinical trials for the treatment of human cancers.

EXPERIMENTAL DESIGN

The effect of GDC-0068 on Akt signaling was characterized using specific biomarkers of the Akt pathway, and response to GDC-0068 was evaluated in human cancer cell lines and xenograft models with various genetic backgrounds, either as a single agent or in combination with chemotherapeutic agents.

RESULTS

GDC-0068 blocked Akt signaling both in cultured human cancer cell lines and in tumor xenograft models as evidenced by dose-dependent decrease in phosphorylation of downstream targets. Inhibition of Akt activity by GDC-0068 resulted in blockade of cell-cycle progression and reduced viability of cancer cell lines. Markers of Akt activation, including high-basal phospho-Akt levels, PTEN loss, and PIK3CA kinase domain mutations, correlate with sensitivity to GDC-0068. Isogenic PTEN knockout also sensitized MCF10A cells to GDC-0068. In multiple tumor xenograft models, oral administration of GDC-0068 resulted in antitumor activity ranging from tumor growth delay to regression. Consistent with the role of Akt in a survival pathway, GDC-0068 also enhanced antitumor activity of classic chemotherapeutic agents.

CONCLUSIONS

GDC-0068 is a highly selective, orally bioavailable Akt kinase inhibitor that shows pharmacodynamic inhibition of Akt signaling and robust antitumor activity in human cancer cells in vitro and in vivo. Our preclinical data provide a strong mechanistic rationale to evaluate GDC-0068 in cancers with activated Akt signaling.

Phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin pathway inhibition: a breakthrough in the management of luminal (ER+/HER2-) breast cancers?

PURPOSE OF REVIEW

Recent data from clinical trials evaluating mammalian target of rapamycin (mTOR) inhibitors in the setting of endocrine resistance in luminal (estrogen receptor-positive, human epidermal growth factor receptor 2-negative) breast cancers have validated this pathway as a bona-fide therapeutic target in this setting. There are currently many agents under clinical investigation that inhibit the phosphatidylinositol 3-kinase (PI3K) pathway. We review these findings in the context of the preclinical data and the current status of biomarker development in this field.

RECENT FINDINGS

Clinical trials in the neoadjuvant (RAD2222) and metastatic setting (TAMRAD, BOLERO-2) have reported improved clinical outcome of patients with unselected luminal breast cancer through the addition of mTOR inhibitors to standard endocrine treatment. PI3K molecular aberrations are frequently found in luminal breast cancer, yet the role of these in defining patients' prognosis and response to PI3K/AKT/mTOR inhibitors remains to be determined.

SUMMARY

Therapeutic targeting of the PI3K pathway promises improved clinical outcome for patients with luminal breast cancer. Correspondingly, agents that target this pathway are entering the clinic at an unprecedented rate. Future clinical trials that incorporate correlative translational research will help us decipher important information critical for successful development of these agents in breast cancer: which part of the pathway should be targeted and in which clinical scenario; and which patients are more likely to benefit from these drugs, particularly in the adjuvant setting.

Disruption of PH-kinase domain interactions leads to oncogenic activation of AKT in human cancers

The protein kinase v-akt murine thymoma viral oncogene homolog (AKT), a key regulator of cell survival and proliferation, is frequently hyperactivated in human cancers. Intramolecular pleckstrin homology (PH) domain-kinase domain (KD) interactions are important in maintaining AKT in an inactive state. AKT activation proceeds after a conformational change that dislodges the PH from the KD. To understand these autoinhibitory interactions, we generated mutations at the PH-KD interface and found that most of them lead to constitutive activation of AKT. Such mutations are likely another mechanism by which activation may occur in human cancers and other diseases. In support of this likelihood, we found somatic mutations in AKT1 at the PH-KD interface that have not been previously described in human cancers. Furthermore, we show that the AKT1 somatic mutants are constitutively active, leading to oncogenic signaling. Additionally, our studies show that the AKT1 mutants are not effectively inhibited by allosteric AKT inhibitors, consistent with the requirement for an intact PH-KD interface for allosteric inhibition. These results have important implications for therapeutic intervention in patients with AKT mutations at the PH-KD interface.

Targeting heat shock factor 1 with a triazole nucleoside analog to elicit potent anticancer activity on drug-resistant pancreatic cancer

Issued from a lead optimization process, we have identified a novel triazole nucleoside analog which elicits potent anticancer activity on drug-resistant pancreatic cancer. Most importantly, this compound targets heat shock response pathways by down-regulation of heat shock transcription factor 1 and consequential down-regulation of multiple heat shock proteins HSP27, HSP70 and HSP90. Down-regulation of these proteins caused the shut-down of several oncogenic pathways and caspase-dependent apoptosis resulting in a potent anticancer effect in vitro and in vivo. These results demonstrate the potential rewards gained in searching for anticancer candidates with multimodal actions on heat shock response pathways via HSF1 down-regulation.

Determination of SGK1 mRNA in non-small cell lung cancer samples underlines high expression in squamous cell carcinomas

Background

Lung cancer represents the most frequent cause of death for cancer. In non-small cell lung cancer (NSCLC), which accounts for the vast majority of this disease, only early detection and treatment, when possible, may significantly affect patient's prognosis. An important role in NSCLC malignancy is attributed to the signal transduction pathways involving PI3Kinase, with consequent activation of the AKT family factors. The serum and glucocorticoid kinase (SGK) factors, which share high structural and functional homologies with the AKT factors, are a family of ubiquitously expressed serine/threonine kinases under the control of cellular stress and hormones. SGK1 is the most represented SGK member.

Methods

By means of immunohistochemistry and quantitative real-time PCR, we determined SGK1 protein and mRNA expression in a cohort of 66 formalin-fixed, paraffin-embedded NSCLC surgical samples. All samples belonged to patients with a well-documented clinical history.

Results

mRNA expression was significantly higher in squamous cell carcinomas, and correlated with several clinical prognostic indicators, being elevated in high-grade tumors and in tumors with bigger size and worse clinical stage. No correlation was found between SGK1 protein expression and these clinical parameters.

Conclusions

This explorative analysis of SGK1 expression in NSCLC samples highlights the potential role of this factor in NSCLC patients' prognosis. Moreover, the higher expression in the squamous cell carcinoma subtype opens new therapeutic possibilities in this NSCLC subtype by designing specific kinase inhibitors.