The Akt pathway in oncology therapy and beyond (Review)

Association of vitamin D receptor gene TaqI polymorphism with Alzheimer's disease in a Southeastern European Caucasian population

The role of vitamin D in Alzheimer's Disease (AD) has been studied over the past years. The results from numerous studies have indicated that the molecular pathways involved in the development of AD are closely related to the molecular pathways of the mechanisms of action of vitamin D. However, only a limited number of studies have described the key role of vitamin D receptor (VDR) in the regulation of the functions of vitamin D and the potential effect of single nucleotide polymorphisms (SNPs) of the VDR gene. Thus, the aim of the present study was to investigate the VDR TaqI polymorphism in relation to AD in a Southeastern European Caucasian (SEC) cohort. Further, the present study aimed to compare the results obtained with those of other AD populations. For this purpose, blood samples from 90 confirmed patients with AD [median age, 74 years; median mini-mental state examination (MMSE) score of 21; median frontal assessment battery (FAB) score of 10] and 103 healthy controls (median age, 57 years) were analyzed to determine the genotypes of TaqI (rs731236) using quantitative PCR. The frequencies (%) of the TaqI TT, TC and CC genotypes in the controls/patients were 34/48.9, 47.6/41.1 and 18.4/10.0, respectively. Statistically significant differences were observed for the TaqI C allele [odds ratio (OR). 0.54; 95% confidence interval (CI), 0.30-0.96; P=0.035], the TaqI TT genotype (OR, 1.86; 95% CI, 1.04-3.32; P=0.035) and the TaqI CC genotype (OR, 0.119; 95% CI, 0.014-0.995; P=0.032,) in relation to the MMSE score <21 in the patient's group. The TaqI TT allele was found to increase the risk of developing AD by 1.86-fold in the SEC population, while the TaqI C allele may act protectively, with a 46% lower risk of developing the disease. Patients with the TaqI CC genotype were found to have an 88% less likelihood of developing severe cognitive impairment based on the MMSE score. On the whole, the present study did not confirm the results of previous studies on the VDR TaqI C allele in patients with AD.

A Dual Anti-Inflammatory and Anti-Proliferative 3-Styrylchromone Derivative Synergistically Enhances the Anti-Cancer Effects of DNA-Damaging Agents on Colon Cancer Cells by Targeting HMGB1-RAGE-ERK1/2 Signaling

The current anti-cancer treatments are not enough to eradicate tumors, and therefore, new modalities and strategies are still needed. Most tumors generate an inflammatory tumor microenvironment (TME) and maintain the niche for their development. Because of the critical role of inflammation via high-mobility group box 1 (HMGB1)–receptor for advanced glycation end-products (RAGE) signaling pathway in the TME, a novel compound possessing both anti-cancer and anti-inflammatory activities by suppressing the HMGB1-RAGE axis provides an effective strategy for cancer treatment. A recent work of our group found that some anti-cancer 3-styrylchromones have weak anti-inflammatory activities via the suppression of this axis. In this direction, we searched such anti-cancer molecules possessing potent anti-inflammatory activities and discovered 7-methoxy-3-hydroxy-styrylchromone (C6) having dual suppressive activities. Mechanism-of-action studies revealed that C6 inhibited the increased phosphorylation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) under the stimulation of HMGB1-RAGE signaling and thereby suppressed cytokine production in macrophage-like RAW264.7 cells. On the other hand, in colorectal cancer HCT116 cells, C6 inhibited the activation of ERK1/2, cyclin-dependent kinase 1, and AKT, down-regulated the protein level of XIAP, and up-regulated pro-apoptotic Bax and caspase-3/7 expression. These alterations are suggested to be involved in the C6-induced suppression of cell cycle/proliferation and initiation of apoptosis in the cancer cells. More importantly, in cancer cells, the treatment of C6 potentiates the anti-cancer effects of DNA-damaging agents. Thus, C6 may be a promising lead for the generation of a novel class of cancer therapeutics.

Toward Development of a Diabetic Synovium Culture Model

Osteoarthritis (OA) is a degenerative joint disease characterized by articular cartilage degradation and inflammation of synovium, the specialized connective tissue that envelops the diarthrodial joint. Type 2 diabetes mellitus (DM) is often found in OA patients, with nearly double the incidence of arthritis reported in patients with diabetes (52%) than those without it (27%). The correlation between OA and DM has been attributed to similar risk factors, namely increasing age and joint loading due to obesity. However, a potential causative link is not well understood due to comorbidities involved with treating diabetic patients, such as high infection rates and poor healing response caused by hyperglycemia and insulin resistance. The purpose of this study was to investigate the effect of hyperglycemic and insulin culture conditions on synovium properties. It was hypothesized that modeling hyperglycemia-induced insulin resistance in synovium would provide novel insights of OA pathogenesis in DM patients. To simulate DM in the synovial joint, healthy synovium was preconditioned in either euglycemic (EG) or hyperglycemic (HG) glucose concentrations with insulin in order to induce the biological response of the diseased phenotype. Synovium biochemical composition was evaluated to determine ECM remodeling under hyperglycemic culture conditions. Concurrent changes in AKT phosphorylation, a signaling pathway implicated in insulin resistance, were measured along with gene expression data for insulin receptors, glucose transporters, and specific glycolysis markers involved in glucose regulation. Since fluid shear stress arising during joint articulation is a relevant upstream stimulus for fibroblast-like synoviocytes (FLS), the predominant cell type in synovium, FLS mechanotransduction was evaluated via intracellular calcium ([Ca²⁺]_i). Incidence and length of primary cilia, a critical effector of cell mechanosensing, were measured as potential mechanisms to support differences in [Ca²⁺]_i responses. Hyperglycemic culture conditions decreased collagen and GAG content compared to EG groups, while insulin recovered ECM constituents. FLS mechanosensitivity was significantly greater in EG and insulin conditions compared to HG and non-insulin treated groups. Hyperglycemic treatment led to decreased incidence and length of primary cilia and decreased AKT phosphorylation, providing possible links to the mechanosensing response and suggesting a potential correlation between glycemic culture conditions, diabetic insulin resistance, and OA development.

Oxidative Stress and AKT-Associated Angiogenesis in a Zebrafish Model and Its Potential Application for Withanolides

Oxidative stress and the AKT serine/threonine kinase (AKT) signaling pathway are essential regulators in cellular migration, metastasis, and angiogenesis. More than 300 withanolides were discovered from the plant family Solanaceae, exhibiting diverse functions. Notably, the relationship between oxidative stress, AKT signaling, and angiogenesis in withanolide treatments lacks comprehensive understanding. Here, we summarize connecting evidence related to oxidative stress, AKT signaling, and angiogenesis in the zebrafish model. A convenient vertebrate model monitored the in vivo effects of developmental and tumor xenograft angiogenesis using zebrafish embryos. The oxidative stress and AKT-signaling-modulating abilities of withanolides were highlighted in cancer treatments, which indicated that further assessments of their angiogenesis-modulating potential are necessary in the future. Moreover, targeting AKT for inhibiting AKT and its AKT signaling shows the potential for anti-migration and anti-angiogenesis purposes for future application to withanolides. This particularly holds for investigating the anti-angiogenetic effects mediated by the oxidative stress and AKT signaling pathways in withanolide-based cancer therapy in the future.

Discovery of Potent, Selective, and In Vivo Efficacious AKT Kinase Protein Degraders via Structure-Activity Relationship Studies

We recently reported a potent, selective, and in vivo efficacious AKT degrader, MS21, which is a von Hippel-Lindau (VHL)-recruiting proteolysis targeting chimera (PROTAC) based on the AKT inhibitor AZD5363. However, no structure-activity relationship (SAR) studies that resulted in this discovery have been reported. Herein, we present our SAR studies that led to the discovery of MS21, another VHL-recruiting AKT degrader, MS143 (compound 20) with similar potency as MS21, and a novel cereblon (CRBN)-recruiting PROTAC, MS5033 (compound 35). Compounds 20 and 35 induced rapid and robust AKT degradation in a concentration- and time-dependent manner via hijacking the ubiquitin-proteasome system. Compound 20 suppressed cell growth more effectively than AZD5363 in multiple cancer cell lines. Furthermore, 20 and 35 displayed good plasma exposure levels in mice and are suitable for in vivo efficacy studies. Lastly, compound 20 effectively suppressed tumor growth in vivo in a xenograft model without apparent toxicity.

Carboxyl-Functionalized Carbon Nanotubes Loaded with Cisplatin Promote the Inhibition of PI3K/Akt Pathway and Suppress the Migration of Breast Cancer Cells

PI3K/Akt signaling is one of the most frequently dysregulated pathways in cancer, including triple-negative breast cancer. With considerable roles in tumor growth and proliferation, this pathway is studied as one of the main targets in controlling the therapies’ efficiency. Nowadays, the development of nanoparticle–drug conjugates attracts a great deal of attention due to the advantages they provide in cancer treatment. Hence, the main purpose of this study was to design a nanoconjugate based on single-walled carbon nanotubes functionalized with carboxyl groups (SWCNT-COOH) and cisplatin (CDDP) and to explore the potential of inhibiting the PI3K/Akt signaling pathway. MDA-MB-231 cells were exposed to various doses (0.01–2 µg/mL SWCNT-COOH and 0.00632–1.26 µg/mL CDDP) of SWCNT-COOH-CDDP and free components for 24 and 48 h. In vitro biological tests revealed that SWCNT-COOH-CDDP had a high cytotoxic effect, as shown by a time-dependent decrease in cell viability and the presence of a significant number of dead cells in MDA-MB-231 cultures at higher doses. Moreover, the nanoconjugates induced the downregulation of PI3K/Akt signaling, as revealed by the decreased expression of PI3K and p-Akt in parallel with PTEN activation, the promotion of Akt protein degradation, and inhibition of tumor cell migration.

NSAIDs and Cancer Resolution: New Paradigms beyond Cyclooxygenase

Acute inflammation or resolved inflammation is an adaptive host defense mechanism and is self-limiting, which returns the body to a state of homeostasis. However, unresolved, uncontrolled, or chronic inflammation may lead to various maladies, including cancer. Important evidence that links inflammation and cancer is that nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin, reduce the risk and mortality from many cancers. The fact that NSAIDs inhibit the eicosanoid pathway prompted mechanistic drug developmental work focusing on cyclooxygenase (COX) and its products. The increased prostaglandin E2 levels and the overexpression of COX-2 in the colon and many other cancers provided the rationale for clinical trials with COX-2 inhibitors for cancer prevention or treatment. However, NSAIDs do not require the presence of COX-2 to prevent cancer. In this review, we highlight the effects of NSAIDs and selective COX-2 inhibitors (COXIBs) on targets beyond COX-2 that have shown to be important against many cancers. Finally, we hone in on specialized pro-resolving mediators (SPMs) that are biosynthesized locally and, in a time, -dependent manner to promote the resolution of inflammation and subsequent tissue healing. Different classes of SPMs are reviewed, highlighting aspirin's potential in triggering the production of these resolution-promoting mediators (resolvins, lipoxins, protectins, and maresins), which show promise in inhibiting cancer growth and metastasis.

A Century of Fractionated Radiotherapy: How Mathematical Oncology Can Break the Rules

Radiotherapy is involved in 50% of all cancer treatments and 40% of cancer cures. Most of these treatments are delivered in fractions of equal doses of radiation (Fractional Equivalent Dosing (FED)) in days to weeks. This treatment paradigm has remained unchanged in the past century and does not account for the development of radioresistance during treatment. Even if under-optimized, deviating from a century of successful therapy delivered in FED can be difficult. One way of exploring the infinite space of fraction size and scheduling to identify optimal fractionation schedules is through mathematical oncology simulations that allow for in silico evaluation. This review article explores the evidence that current fractionation promotes the development of radioresistance, summarizes mathematical solutions to account for radioresistance, both in the curative and non-curative setting, and reviews current clinical data investigating non-FED fractionated radiotherapy.

Multiple proliferation signaling pathways are modulated by octacalcium phosphate in osteoblasts

Octacalcium phosphate (OCP), a type of bioactive ceramics, may be associated with dentine, tooth apatite, and especially bone generation, and promotes wound healing after fracture. Recently, commercial bone grafting products containing a large amount of OCP material have been released because OCP can be synthesized in large quantities. It is reported to increase cell proliferation, but the interaction between OCP and cell signaling pathways is still unclear. In this study, first, we demonstrated OCP mediated cell signaling pathways with only purified OCP materials. OCP regulated P38, JNK (c-Jun N-terminal kinase), Src, and AKT (protein kinase B) signaling pathways. OCP crystals appeared in the characteristic ribbon shape but varied by several tens of micrometers in size. The X-ray diffraction pattern was the same as previously reported. We studied two concentrations of OCP (10 mg/ml and 20 mg/ml) to understand whether the effect of OCP on cell signaling pathways is dose dependent. We confirmed that OCP treatment affected cell proliferation and alkaline phosphatase and disrupted Src phosphorylation but did not change the total protein level. P38 phosphorylation was activated with OCP treatment and inhibited by SB203580, but P38 total protein level did not change. OCP inhibited JNK phosphorylation signaling, whereas PD98509 inhibited JNK phosphorylation with or without OCP. Interestingly, the AKT total level decreased after OCP treatment, but AKT phosphorylation increased considerably. Our results demonstrate that OCP materials modulate cell signaling pathways and increase cell proliferation.

Anticancer peptide Q7 suppresses the growth and migration of human endometrial cancer by inhibiting DHCR24 expression and modulating the AKT-mediated pathway

Endometrial cancer is one of the most common malignancy affecting women in developed countries. Resection uterus or lesion area is usually the first option for a simple and efficient therapy. Therefore, it is necessary to find a new therapeutic drug to reduce surgery areas to preserve fertility. Anticancer peptides (ACP) are bioactive amino acids with lower toxicity and higher specificity than chemical drugs. This study is to address an ACP, herein named Q7, which could downregulate 24-Dehydrocholesterol Reductase (DHCR24) to disrupt lipid rafts formation, and sequentially affect the AKT signal pathway of HEC-1-A cells to suppress their tumorigenicity such as proliferation and migration. Moreover, lipo-PEI-PEG-complex (LPPC) was used to enhance Q7 anticancer activity in vitro and efficiently show its effects on HEC-1-A cells. Furthermore, LPPC-Q7 exhibited a synergistic effect in combination with doxorubicin or paclitaxel. To summarize, Q7 was firstly proved to exhibit an anticancer effect on endometrial cancer cells and combined with LPPC efficiently improved the cytotoxicity of Q7.

Design, Synthesis, and Evaluation of Potent, Selective, and Bioavailable AKT Kinase Degraders

The serine/threonine kinase AKT functions as a critical node of the phosphatidylinositol 3-kinase (PI3K)/AKT/mammalian target of rapamycin (m-TOR) signaling pathway. Aberrant activation and overexpression of AKT are strongly correlated with numerous human cancers. To date, only two AKT degraders with no structure-activity relationship (SAR) results have been reported. Through extensive SAR studies on various linkers, E3 ligase ligands, and AKT binding moieties, we identified two novel and potent AKT proteolysis targeting chimera (PROTAC) degraders: von Hippel-Lindau (VHL)-recruiting degrader 13 (MS98) and cereblon (CRBN)-recruiting degrader 25 (MS170). These two compounds selectively induced robust AKT protein degradation, inhibited downstream signaling, and suppressed cancer cell proliferation. Moreover, these two degraders exhibited good plasma exposure levels in mice through intraperitoneal injection. Overall, our comprehensive SAR studies led to the discovery of degraders 13 and 25, which are potentially useful chemical tools to investigate biological and pathogenic functions of AKT in vitro and in vivo.

The Potential of Hsp90 in Targeting Pathological Pathways in Cardiac Diseases

Heat shock protein 90 (Hsp90) is a molecular chaperone that interacts with up to 10% of the proteome. The extensive involvement in protein folding and regulation of protein stability within cells makes Hsp90 an attractive therapeutic target to correct multiple dysfunctions. Many of the clients of Hsp90 are found in pathways known to be pathogenic in the heart, ranging from transforming growth factor β (TGF-β) and mitogen activated kinase (MAPK) signaling to tumor necrosis factor α (TNFα), G_s and G_q g-protein coupled receptor (GPCR) and calcium (Ca²⁺) signaling. These pathways can therefore be targeted through modulation of Hsp90 activity. The activity of Hsp90 can be targeted through small-molecule inhibition. Small-molecule inhibitors of Hsp90 have been found to be cardiotoxic in some cases however. In this regard, specific targeting of Hsp90 by modulation of post-translational modifications (PTMs) emerges as an attractive strategy. In this review, we aim to address how Hsp90 functions, where Hsp90 interacts within pathological pathways, and current knowledge of small molecules and PTMs known to modulate Hsp90 activity and their potential as therapeutics in cardiac diseases.

Cancer-A Major Cardiac Comorbidity With Implications on Cardiovascular Metabolism

Cardiovascular diseases have multifactorial causes. Classical cardiovascular risk factors, such as arterial hypertension, smoking, hyperlipidemia, and diabetes associate with the development of vascular stenoses and coronary heart disease. Further comorbidities and its impact on cardiovascular metabolism have gotten more attention recently. Thus, also cancer biology may affect the heart, apart from cardiotoxic side effects of chemotherapies. Cancer is a systemic disease which primarily leads to metabolic alterations within the tumor. An emerging number of preclinical and clinical studies focuses on the interaction between cancer and a maladaptive crosstalk to the heart. Cachexia and sarcopenia can have dramatic consequences for many organ functions, including cardiac wasting and heart failure. These complications significantly increase mortality and morbidity of heart failure and cancer patients. There are concurrent metabolic changes in fatty acid oxidation (FAO) and glucose utilization in heart failure as well as in cancer, involving central molecular regulators, such as PGC-1α. Further, specific inflammatory cytokines (IL-1β, IL-6, TNF-α, INF-β), non-inflammatory cytokines (myostatin, SerpinA3, Ataxin-10) and circulating metabolites (D2-HG) may mediate a direct and maladaptive crosstalk of both diseases. Additionally, cancer therapies, such as anthracyclines and angiogenesis inhibitors target common metabolic mechanisms in cardiomyocytes and malignant cells. This review focuses on cardiovascular, cancerous, and cancer therapy-associated alterations on the systemic and cardiac metabolic state.

The Secretome of Human Neonatal Mesenchymal Stem Cells Modulates Doxorubicin-Induced Cytotoxicity: Impact in Non-Tumor Cells

Doxorubicin (Dox) is one of the most widely used treatments for breast cancer, although limited by the well-documented cardiotoxicity and other off-target effects. Mesenchymal stem cell (MSC) secretome has shown immunomodulatory and regenerative properties, further potentiated under 3D conditions. This work aimed to uncover the effect of the MSC-derived secretome from 3D (CM3D) or 2D (CM2D) cultures, in human malignant breast cells (MDA-MB-231), non-tumor breast epithelial cells (MCF10A) and differentiated AC16 cardiomyocytes, co-treated with Dox. A comprehensive proteomic analysis of CM3D/CM2D was also performed to unravel the underlying mechanism. CM3D/CM2D co-incubation with Dox revealed no significant differences in MDA-MB-231 viability when compared to Dox alone, whereas MCF10A and AC16 viability was consistently improved in Dox+CM3D-treated cells. Moreover, neither CM2D nor CM3D affected Dox anti-migratory and anti-invasive effects in MDA-MB-231. Notably, Ge-LC-MS/MS proteomic analysis revealed that CM3D displayed protective features that might be linked to the regulation of cell proliferation (CAPN1, CST1, LAMC2, RANBP3), migration (CCN3, MMP8, PDCD5), invasion (TIMP1/2), oxidative stress (COX6B1, AIFM1, CD9, GSR) and inflammation (CCN3, ANXA5, CDH13, GDF15). Overall, CM3D decreased Dox-induced cytotoxicity in non-tumor cells, without compromising Dox chemotherapeutic profile in malignant cells, suggesting its potential use as a chemotherapy adjuvant to reduce off-target side effects.

The Crosstalk Between Signaling Pathways and Cancer Metabolism in Colorectal Cancer

Colorectal cancer (CRC) is one of the most frequently diagnosed cancers worldwide. Metabolic reprogramming represents an important cancer hallmark in CRC. Reprogramming core metabolic pathways in cancer cells, such as glycolysis, glutaminolysis, oxidative phosphorylation, and lipid metabolism, is essential to increase energy production and biosynthesis of precursors required to support tumor initiation and progression. Accumulating evidence demonstrates that activation of oncogenes and loss of tumor suppressor genes regulate metabolic reprogramming through the downstream signaling pathways. Protein kinases, such as AKT and c-MYC, are the integral components that facilitate the crosstalk between signaling pathways and metabolic pathways in CRC. This review provides an insight into the crosstalk between signaling pathways and metabolic reprogramming in CRC. Targeting CRC metabolism could open a new avenue for developing CRC therapy by discovering metabolic inhibitors and repurposing protein kinase inhibitors/monoclonal antibodies.

Targeting PI3K/Akt/mTOR Pathway by Different Flavonoids: A Cancer Chemopreventive Approach

Cancer is, globally, one of the main causes of death. Even though various therapies are available, they are still painful because of their adverse side effects. Available treatments frequently fail due to unpromising responses, resistance to classical anticancer drugs, radiation therapy, chemotherapy, and low accessibility to tumor tissues. Developing novel strategies to minimize adverse side effects, improve chemotherapy sensitivity, and control cancer progression is needed. Many studies have suggested small dietary molecules as complementary treatments for cancer patients. Different components of herbal/edible plants, known as flavonoids, have recently garnered attention due to their broad biological properties (e.g., antioxidant, antiviral, antimicrobial, anti-inflammatory, anti-mutagenic, anticancer, hepatoprotective, and cardioprotective). These flavonoids have shown anticancer activity by affecting different signaling cascades. This article summarizes the key progress made in this area and discusses the role of flavonoids by specifically inhibiting the PI3K/Akt/mTOR pathway in various cancers.

Metformin synergistically increases the anticancer effects of lapatinib through induction of apoptosis and modulation of Akt/AMPK pathway in SK-BR3 breast cancer cell line

Objectives

Combination chemotherapy is a beneficial intervention for breast cancer, versus single therapy. We investigated the effect of Metformin (Met) on Lapatinib (Lap)-induced apoptosis in SK-BR3 cells.

Materials and Methods

Toxic effect of Met and Lap on SK-BR3 cells was measured using MTT assay. Flow cytometry was used to measure the co-treatment effect of Met on lapatinib-induced apoptosis. The relative expression of Bax, Bcl2, and P21 was measured using a real-time PCR. The activity of caspase 3 and 9 was measured using an ELISA kit. The protein level of AMPK and Akt was determined using Western blot analysis.

Results

Metformin and lapatinib alone and combined form showed significant time- and dose-dependent toxic effects on SK-BR3 cell viability. The greatest synergistic inhibitory effect on the cell viability [combination index (CI) = 0.51] was remarkable at Met 100 mM combined with Lap 100 nM. The combination has a stronger apoptotic death (46%) versus lapatinib alone. The combination considerably increased the mRNA expression of Bax and P21, and caspase 3 and 9 activity, while, decreasing the mRNA expression of Bcl2. Additionally, the combination significantly up-regulated and down-regulated the protein levels of AMPK and Akt, respectively.

Conclusion

The metformin-lapatinib combination can induce more potent apoptotic death versus each compound individually. The combination may be suggested as a valuable therapeutic intervention in patients with breast cancer. However, additional in vivo studies are necessary to evaluate the clinical use of the combination for induction of apoptosis and its antitumor effects.

CKB inhibits epithelial-mesenchymal transition and prostate cancer progression by sequestering and inhibiting AKT activation

Epithelial-mesenchymal transition (EMT) contributes to tumor invasion, metastasis and drug resistance. AKT activation is key in a number of cellular processes. While many positive regulators for either EMT or AKT activation have been reported, few negative regulators are established. Through kinase cDNA screen, we identified brain-type creatine kinase (CKB or BCK) as a potent suppressor for both. As a ubiquitously expressed kinase in normal tissues, CKB is significantly downregulated in several solid cancer types. Lower CKB expression is significantly associated with worse prognosis. Phenotypically, CKB overexpression suppresses, while its silencing promotes, EMT and cell migration, xenograft tumor growth and metastasis of prostate cancer cells. AKT activation is one of the most prominent signaling events upon CKB silencing in prostate cancer cells, which is in line with prostate cancer TCGA data. EMT enhanced by CKB silencing is abolished by AKT inhibition. Mechanistically, CKB interacts with AKT and sequestrates it from activation by mTOR. We further elucidated that an 84aa fragment at C-terminus of CKB protein interacts with AKT's PH domain. Ectopic expression of the 84aa CKB fragment inhibits AKT activation, EMT and cell proliferation. Interestingly, molecular dynamics simulation on crystal structures of AKT and CKB independently demonstrates that AKT's PH domain and CKB's 84aa fragment establish their major interaction interface. In summary, we have discovered CKB as a negative regulator of EMT and AKT activation, revealing a new mode of their regulation . We have also demonstrated that CKB downregulation is a poor prognosticator, which is sufficient to promote prostate cancer progression.

FPR2 serves a role in recurrent spontaneous abortion by regulating trophoblast function via the PI3K/AKT signaling pathway

Recurrent spontaneous abortion (RSA) effects both the physical and mental health of women of reproductive age. Trophoblast dysfunction may result in RSA due to shallow placental implantation. The mechanisms underlying formyl peptide receptor 2 (FPR2) on the biological functions of trophoblasts remain to be elucidated. The present study aimed to explore the potential functions of FPR2, a G protein‑coupled receptor, in placental trophoblasts. The location and expression levels of FPR2 in the villi tissue of patients with RSA were detected using immunohistochemical staining, reverse transcription‑quantitative PCR and western blotting. Following the transfection of small interfering RNA targeting FPR2 in HTR‑8/SVneo cells, a Cell Counting Kit‑8 assay was used to determine the levels of cell viability. Flow cytometry was used to examine the levels of cell apoptosis and gap closure and Transwell assays were carried out to evaluate the levels of cell migration and invasion. A tube formation assay was performed to detect the levels of capillary‑like structure formation. Western blotting was used to detect the expression levels of proteins in the associated signaling pathways. The expression of FPR2 was present in villi trophoblasts and was markedly increased in patients with RSA. The levels of trophoblast invasion, migration and tube formation were markedly increased following FPR2 knockdown, whereas the levels of apoptosis were markedly decreased. In addition, FPR2 knockdown caused an increase in the phosphorylation levels of AKT and PI3K. Thus, FPR2 may be involved in the regulation of trophoblast function via the PI3K/AKT signaling pathway. The results of the present study provided a theoretical basis for the use of FPR2 as a target for the treatment of trophoblast‑associated diseases, such as RSA.

7-Epitaxol Induces Apoptosis and Autophagy in Head and Neck Squamous Cell Carcinoma through Inhibition of the ERK Pathway

As the main derivative of paclitaxel, 7-Epitaxol is known to a have higher stability and cytotoxicity. However, the anticancer effect of 7-Epitaxol is still unclear. The purpose of this study was to explore the anticancer effects of 7-Epitaxol in squamous cell carcinoma of the head and neck (HNSCC). Our study findings revealed that 7-Epitaxol potently suppressed cell viability in SCC-9 and SCC-47 cells by inducing cell cycle arrest. Flow cytometry and DAPI staining demonstrated that 7-Epitaxol treatment induced cell death, mitochondrial membrane potential and chromatin condensation in OSCC cell lines. The compound regulated the proteins of extrinsic and intrinsic pathways at the highest concentration, and also increased the activation of caspases 3, 8, 9, and PARP in OSCC cell lines. Interestingly, a 7-Epitaxol-mediated induction of LC3-I/II expression and suppression of p62 expression were observed in OSCC cells lines. Furthermore, the MAPK inhibitors indicated that 7-Epitaxol induces apoptosis and autophagy marker proteins (cleaved-PARP and LC3-I/II) by reducing the phosphorylation of ERK1/2. In conclusion, these findings indicate the involvement of 7-Epitaxol in inducing apoptosis and autophagy through ERK1/2 signaling pathway, which identify 7-Epitaxol as a potent cytotoxic agent in HNSCC.

Insights into Mechanisms of Tumorigenesis in Neuroendocrine Neoplasms

Genomic studies have identified some of the most relevant genetic players in Neuroendocrine Neoplasm (NEN) tumorigenesis. However, we are still far from being able to draw a model that encompasses their heterogeneity, elucidates the different biological effects consequent to the identified molecular events, or incorporates extensive knowledge of molecular biomarkers and therapeutic targets. Here, we reviewed recent insights in NEN tumorigenesis from selected basic research studies on animal models, highlighting novel players in the intergenic cooperation and peculiar mechanisms including splicing dysregulation, chromatin stability, or cell dedifferentiation. Furthermore, models of tumorigenesis based on composite interactions other than a linear progression of events are proposed, exemplified by the involvement in NEN tumorigenesis of genes regulating complex functions, such as MEN1 or DAXX. Although limited by interspecies differences, animal models have proved helpful for the more in-depth study of every facet of tumorigenesis, showing that the identification of driver mutations is only one of the many necessary steps and that other mechanisms are worth investigating.

FOXO3a inhibits nephroblastoma cell proliferation, migration and invasion, and induces apoptosis through downregulating the Wnt/β‑catenin signaling pathway

Forkhead transcription factor O subfamily 3A (FOXO3a) is an important tumor suppressor gene that is expressed in renal tissue and has been reported to be downregulated in clear cell renal cell carcinoma (CCRCC). Notably, the overexpression of FOXO3a was previously discovered to inhibit the progression of CCRCC. However, the expression levels of FOXO3a in nephroblastoma cell lines remain unknown. The present study aimed to investigate the expression levels of FOXO3a in nephroblastoma cell lines and to determine the mechanism of action of the biological functions of FOXO3a. Western blotting and reverse transcription‑quantitative PCR were used to analyze the expression levels of FOXO3a in nephroblastoma cell lines. Subsequently, the effects of the overexpression of FOXO3a and the genetic knockdown of the Wnt/β‑catenin signaling protein Axin‑2 on the biological functions were determined through Cell Counting Kit‑8, cell colony formation assays, scratch and Transwell assay and flow cytometric analysis experiments. The expression levels of FOXO3a were discovered to be downregulated in nephroblastoma cell lines. The overexpression of FOXO3a inhibited the proliferation, invasion and migration of nephroblastoma cells, while inducing apoptosis. Furthermore, the overexpression of FOXO3a downregulated the expression levels of β‑catenin and Cyclin‑D1 proteins involved in the Wnt/β‑catenin signaling pathway. Cell proliferation and the migration and invasion ability of 17‑94 cells in shRNA‑Axin2‑2 group were promoted. Cell apoptosis was predominantly increased by overexpressed FOXO3a, which was reversed by shRNA‑Axin2‑1. The biological effects of overexpressing FOXO3a on nephroblastoma were reversed after activation of Wnt/β‑catenin. In conclusion, the findings of the present study suggested that FOXO3a may inhibit nephroblastoma cell proliferation, migration and invasion, while inducing apoptosis, by downregulating the Wnt/β‑catenin signaling pathway. These results may provide a novel method for the early diagnosis and precise treatment of nephroblastoma.

Inhibitors of the PI3K/Akt/mTOR Pathway in Prostate Cancer Chemoprevention and Intervention

The phosphatidylinositol 3-kinase (PI3K)/serine-threonine kinase (Akt)/mammalian target of the rapamycin (mTOR)-signaling pathway has been suggested to have connections with the malignant transformation, growth, proliferation, and metastasis of various cancers and solid tumors. Relevant connections between the PI3K/Akt/mTOR pathway, cell survival, and prostate cancer (PC) provide a great therapeutic target for PC prevention or treatment. Recent studies have focused on small-molecule mTOR inhibitors or their usage in coordination with other therapeutics for PC treatment that are currently undergoing clinical testing. In this study, the function of the PI3K/Akt/mTOR pathway, the consequence of its dysregulation, and the development of mTOR inhibitors, either as an individual substance or in combination with other agents, and their clinical implications are discussed. The rationale for targeting the PI3K/Akt/mTOR pathway, and specifically the application and potential utility of natural agents involved in PC treatment is described. In addition to the small-molecule mTOR inhibitors, there are evidence that several natural agents are able to target the PI3K/Akt/mTOR pathway in prostatic neoplasms. These natural mTOR inhibitors can interfere with the PI3K/Akt/mTOR pathway through multiple mechanisms; however, inhibition of Akt and suppression of mTOR 1 activity are two major therapeutic approaches. Combination therapy improves the efficacy of these inhibitors to either suppress the PC progression or circumvent the resistance by cancer cells.

Dendrobium mixture attenuates renal damage in rats with diabetic nephropathy by inhibiting the PI3K/Akt/mTOR pathway

Dendrobium mixture (DMix) is a Traditional Chinese Medicine widely used for preventing and treating diabetic nephropathy (DN). Autophagy contributes to DN development and progression. The present study aimed to investigate the mechanism underlying the protective effects of DMix on the kidneys of rats with DN and to determine whether this involves autophagy. Herein, a high‑sugar and high‑fat diet, combined with the intra‑abdominal injection of low‑dose streptozocin, was used to induce DN in 40 Sprague‑Dawley male rats. In total, 10 additional rats were used as controls. The rats with DN were then randomly divided into three groups and treated with DMix, gliquidone or saline via gastric administration for 8 weeks. Body weight, kidney weight, kidney index, fasting blood glucose (FBG), blood lipid, hemoglobin A1c (HbA1c), insulin, blood urea nitrogen and serum creatinine levels, as well as the 24‑h urinary albumin excretion rate (UAER) were measured. H&E, Periodic Acid‑Schiff and Masson staining were used to examine the renal pathology. The mRNA and protein expression levels of LC3 and Beclin‑1 in renal tissues were measured using reverse transcription‑quantitative PCR and immunohistochemistry, respectively. Western blotting was conducted to measure the protein expression levels of PI3K, phosphorylated (p)‑PI3K, Akt, p‑Akt, mTOR, p‑mTOR, LC3 and Beclin‑1 in renal tissues. It was found that DMix significantly reduced the FBG, blood lipids, HbA1c and insulin levels, kidney weight, kidney index and UAER in rats with DN, as well as improved renal function. Rats with DN showed notable glomerular hypertrophy, an increase in mesangial matrix content and renal interstitial fibrosis. Moreover, DMix notably reduced kidney damage. The results demonstrated that DMix inhibited the phosphorylation of PI3K, Akt and mTOR in the kidney tissues of rats with DN, and increased the protein and mRNA expression levels of LC3 and Beclin‑1. Therefore, it was suggested that DMix has protective effects on the kidney of rats with DN, which may be associated with the inhibition of the PI3K/Akt/mTOR signaling pathway and activation of renal autophagy by this traditional medicine.

The Green Anti-Cancer Weapon. The Role of Natural Compounds in Bladder Cancer Treatment

Bladder cancer (BC) is the second most common genitourinary cancer. In 2018, 550,000 people in the world were diagnosed with BC, and the number of new cases continues to rise. BC is also characterized by high recurrence risk, despite therapies. Although in the last few years, the range of BC therapy has considerably widened, it is associated with severe side effects and the development of drug resistance, which is hampering treatment success. Thus, patients are increasingly choosing products of natural origin as an alternative or complementary therapeutic options. Therefore, in this article, we aim to elucidate, using the available literature, the role of natural substances such as curcumin, sulforaphane, resveratrol, quercetin, 6-gingerol, delphinidin, epigallocatechin-3-gallate and gossypol in the BC treatment. Numerous clinical and preclinical studies point to their role in the modulation of the signaling pathways, such as cell proliferation, cell survival, apoptosis and cell death.

Kir4.1 may represent a novel therapeutic target for diabetic retinopathy (Review)

As the major cause of irreversible loss of vision in adults, diabetic retinopathy (DR) is one of the most serious complications of diabetes. The imbalance of the retinal microenvironment and destruction of the blood-retinal barrier have a significant role in the progression of DR. Inward rectifying potassium channel 4.1 (Kir4.1) is located on Müller cells and is closely related to potassium homeostasis, water balance and glutamate clearance in the whole retina. The present review discusses the functions of Kir4.1 in regulating the retinal microenvironment and related biological mechanisms in DR. In the future, Kir4.1 may represent a novel alternative therapeutic target for DR through affecting the retinal microenvironment.

Targeting PI3K/AKT/mTOR Signaling Pathway in Breast Cancer

Breast cancer is the most frequently diagnosed cancer and the primary cause of cancer death in women worldwide. Although early diagnosis and cancer growth inhibition has significantly improved breast cancer survival rate over the years, there is a current need to develop more effective systemic treatments to prevent metastasis. One of the most commonly altered pathways driving breast cancer cell growth, survival, and motility is the PI3K/AKT/mTOR signaling cascade. In the past 30 years, a great surge of inhibitors targeting these key players has been developed at a rapid pace, leading to effective preclinical studies for cancer therapeutics. However, the central role of PI3K/AKT/mTOR signaling varies among diverse biological processes, suggesting the need for more specific and sophisticated strategies for their use in cancer therapy. In this review, we provide a perspective on the role of the PI3K signaling pathway and the most recently developed PI3K-targeting breast cancer therapies.

Akt phosphorylates insulin receptor substrate to limit PI3K-mediated PIP3 synthesis

The phosphoinositide 3-kinase (PI3K)-Akt network is tightly controlled by feedback mechanisms that regulate signal flow and ensure signal fidelity. A rapid overshoot in insulin-stimulated recruitment of Akt to the plasma membrane has previously been reported, which is indicative of negative feedback operating on acute timescales. Here, we show that Akt itself engages this negative feedback by phosphorylating insulin receptor substrate (IRS) 1 and 2 on a number of residues. Phosphorylation results in the depletion of plasma membrane-localised IRS1/2, reducing the pool available for interaction with the insulin receptor. Together these events limit plasma membrane-associated PI3K and phosphatidylinositol (3,4,5)-trisphosphate (PIP3) synthesis. We identified two Akt-dependent phosphorylation sites in IRS2 at S306 (S303 in mouse) and S577 (S573 in mouse) that are key drivers of this negative feedback. These findings establish a novel mechanism by which the kinase Akt acutely controls PIP3 abundance, through post-translational modification of the IRS scaffold.

Fuzheng Jiedu Xiaoji formulation inhibits hepatocellular carcinoma progression in patients by targeting the AKT/CyclinD1/p21/p27 pathway

BACKGROUND

Hepatocellular carcinoma (HCC) is a common malignant tumor with limited treatment options. Conventional antitumor therapy combined with traditional Chinese medicine (TCM) to limit tumor progression has gradually become the focus of complementary and alternative therapies for HCC treatment. The Fuzheng Jiedu Xiaoji formulation (FZJDXJ) alleviates the clinical symptoms of patients and inhibits tumor progression, but its curative effect still requires extensive clinical research and mechanistic analysis.

PURPOSE

To explore the effectiveness of FZJDXJ in HCC patients and investigate its biological function and mechanism underlying anticancer therapy.

METHODS

This randomized controlled clinical trial enrolled 291 HCC patients receiving transcatheter arterial chemoembolization (TACE) therapy; patients received either FZJDXJ combined with standard treatment, or standard treatment alone, for 48 weeks. Statistical analyses were performed according to survival time at the end of the trial. The main constituents of the FZJDXJ extracts were identified and evaluated using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) and molecular docking. The antitumor effects of FZJDXJ and its specific biological mechanism of action were studied.

RESULTS

After 48 weeks of treatment, one-year overall survival (OS) and progression-free survival (PFS) were significantly different between the two groups. Co-administration of FZJDXJ and TACE prolonged the OS of HCC patients, especially in BCLC A or B stage. FZJDXJ and TACE treatment effectively extended the PFS of patients, especially in the BCLC B stage. HPLC-MS/MS identified 1619 active constituents of FZJDXJ, including formononetin, chlorogenic acid (CGA), caffeic acid, luteolin, gallic acid, diosgenin, ergosterol endoperoxide, and lupeol, which may function through the AKT/CyclinD1/p21/p27 pathways. Through molecular docking, CGA and gallic acid could effectively combine with Thr308, an important phosphorylation site of AKT1. FZJDXJ inhibited tumor growth in nude mice. In vitro, FZJDXJ-mediated serum inhibited the proliferation, migration, and invasion of liver cancer cells, and promoted cell apoptosis.

CONCLUSION

Clinically, FZJDXJ combined with TACE therapy significantly prolonged OS and PFS and reduced the mortality rate of HCC patients. Mechanistically, FZJDXJ effectively inhibited the proliferation and migration of liver cancer cells through the modulation of the AKT/CyclinD1/p21/p27 pathways, and may be a promising TCM drug for anti-HCC therapy.

Feedback, Crosstalk and Competition: Ingredients for Emergent Non-Linear Behaviour in the PI3K/mTOR Signalling Network

The PI3K/mTOR signalling pathway plays a central role in the governing of cell growth, survival and metabolism. As such, it must integrate and decode information from both external and internal sources to guide efficient decision-making by the cell. To facilitate this, the pathway has evolved an intricate web of complex regulatory mechanisms and elaborate crosstalk with neighbouring signalling pathways, making it a highly non-linear system. Here, we describe the mechanistic biological details that underpin these regulatory mechanisms, covering a multitude of negative and positive feedback loops, feed-forward loops, competing protein interactions, and crosstalk with major signalling pathways. Further, we highlight the non-linear and dynamic network behaviours that arise from these regulations, uncovered through computational and experimental studies. Given the pivotal role of the PI3K/mTOR network in cellular homeostasis and its frequent dysregulation in pathologies including cancer and diabetes, a coherent and systems-level understanding of the complex regulation and consequential dynamic signalling behaviours within this network is imperative for advancing biology and development of new therapeutic approaches.

Integrated Analysis of Genomic and Immunological Features in Lung Adenocarcinoma With Micropapillary Component

Background

Micropapillary adenocarcinoma is one of the most aggressive histologic subtypes of lung adenocarcinoma (LADC), and even a minor proportion of micropapillary component (MPC) within the LADC could contribute to poor prognosis. Comprehensive analysis of genetic and immunological features of LADC with different percentages of MPC would help better understand cancer biology of this LADC subtype and direct future treatments.

Methods

We performed next-generation sequencing (NGS) for a discovery cohort of 43 LADC patients whose tumors were micro-dissected to separate MPC and non-MPC lesions and a reference cohort of 113 LADC patients. MPC-enriched genetic alterations that were detected in the discovery cohort were then confirmed using a validation cohort of 183 LADC patients. Immunological staining was also conducted on the MPC-containing samples in the discovery cohort.

Results

Tumors with a higher percentage of MPC tended to harbor more tumor mutation burdens (TMBs) and chromosome instability (CIN). Some rare genetic events may serve as the genetic landscape to drive micropapillary tumor progression. Specifically, alterations in transcription termination factor 1 (TTF1), brain-specific angiogenesis inhibitor 3 (BAI3), mammalian target of rapamycin (MTOR), and cyclin-dependent kinase inhibitor 2A (CDKN2A) were cross-validated to be enriched in MPC-contained LADC. Additionally, tumors with a higher percentage of MPC were associated with a higher percentage of CD4+, CD8+, and PD-L1+ staining, and some genetic changes that were enriched in MPC, including MET amplification and MTOR mutation, were correlated with increased PD-L1 expression.

Conclusion

We identified multiple novel MPC-enriched genetic changes that could help us understand the nature of this aggressive cancer subtype. High MPC tumors tended to have elevated levels of TMBs, T cell infiltration, and immunosuppression than low MPC tumors, implying the potential link between MPC content and sensitivity to immunotherapy.

ELOVL2: a novel tumor suppressor attenuating tamoxifen resistance in breast cancer

Epigenetic events have successfully explained the cause of various cancer types, but little is known about tamoxifen resistance (TamR) that induces cancer recurrence. In this study, via genome-wide methylation analysis in MCF-7/TamR cells we show that elongation of very-long chain fatty acid protein 2 (ELOVL2) was hypermethylated and downregulated in the samples from TamR breast cancer patients (n = 28) compared with those from Tam-sensitive (TamS) patients (n = 33) (P < 0.001). Strikingly, in addition to having tumor suppressor activity, ELOVL2 was shown to recover Tam sensitivity up to 70% in the MCF-7/TamR cells and in a xenograft mouse model. A group of genes in the AKT and ERa signaling pathways, e.g., THEM4, which play crucial roles in drug resistance, were found to be regulated by ELOVL2. This study implies that the deregulation of a gene in fatty acid metabolism can lead to drug resistance, giving insight into the development of a new therapeutic strategy for drug-resistant breast cancer.

Mechanism underlying long non‑coding RNA ILF3‑AS1‑mediated inhibition of cervical cancer cell proliferation, invasion and migration, and promotion of apoptosis

Long non-coding RNA ILF3 divergent transcript (ILF3-AS1) displays a tumor-suppressing effect. StarBase predicted that the potential target microRNA (miR) of ILF3-AS1 was miR-454-3p; therefore, the present study investigated the effect of ILF3-AS1 and its target miR-454-3p on cervical cancer (CC). Gene Expression Profiling Interactive Analysis was used to predict the expression of ILF3-AS1 in CC and the overall survival rate of patients. The present study demonstrated that ILF3-AS1 expression was significantly downregulated in human CC tissues and cells compared with adjacent tissues (ANTs) and normal cervical epithelial cells (NCEs), respectively. Patients with CC with high ILF3-AS1 expression displayed higher survival rates compared with patients with low ILF3-AS1 expression. Cell viability, apoptosis, migration and invasion were detected by performing Cell Counting Kit-8, flow cytometry, wound healing and Transwell assays, respectively. Compared with the negative control (NC) group, ILF3-AS1 overexpression significantly inhibited CC cell viability and migration, but significantly increased CC cell apoptosis. Moreover, ILF3-AS1 overexpression significantly upregulated E-Cadherin expression levels, but significantly downregulated N-Cadherin and snail family transcriptional repressor 1 expression levels compared with the NC group. miR-454-3p expression was negatively correlated with ILF3-AS1, and highly expressed in CC tissues and cells compared with ANTs and NCEs, respectively. PTEN, which was predicted and verified as the target gene for miR-454-3p, was significantly downregulated in CC tissues and cells compared with ANTs and NCEs, respectively. ILF3-AS1 expression was positively correlated with PTEN expression, and ILF3-AS1 overexpression partially reversed the inhibitory effect of miR-454-3p on PTEN expression. In conclusion, the present study indicated that ILF3-AS1 inhibited CC cell proliferation and migration, and promoted CC cell apoptosis by inhibiting epithelial-mesenchymal transition, and ILF3-AS1 overexpression partially reversed the inhibitory effect of miR-454-3p on PTEN expression.

Isolation and Establishment of a Highly Proliferative, Cancer Stem Cell-Like, and Naturally Immortalized Triple-Negative Breast Cancer Cell Line, KAIMRC2

In vitro studies of a disease are key to any in vivo investigation in understanding the disease and developing new therapy regimens. Immortalized cancer cell lines are the best and easiest model for studying cancer in vitro. Here, we report the establishment of a naturally immortalized highly tumorigenic and triple-negative breast cancer cell line, KAIMRC2. This cell line is derived from a Saudi Arabian female breast cancer patient with invasive ductal carcinoma. Immunocytochemistry showed a significant ratio of the KAIMRC2 cells’ expressing key breast epithelial and cancer stem cells (CSCs) markers, including CD47, CD133, CD49f, CD44, and ALDH-1A1. Gene and protein expression analysis showed overexpression of ABC transporter and AKT-PI3Kinase as well as JAK/STAT signaling pathways. In contrast, the absence of the tumor suppressor genes p53 and p73 may explain their high proliferative index. The mice model also confirmed the tumorigenic potential of the KAIMRC2 cell line, and drug tolerance studies revealed few very potent candidates. Our results confirmed an aggressive phenotype with metastatic potential and cancer stem cell-like characteristics of the KAIMR2 cell line. Furthermore, we have also presented potent small molecule inhibitors, especially Ryuvidine, that can be further developed, alone or in synergy with other potent inhibitors, to target multiple cancer-related pathways.

MiR-221/222 Ameliorates Deoxynivalenol-Induced Apoptosis and Proliferation Inhibition in Intestinal Epithelial Cells by Targeting PTEN

Intestinal epithelial cells are critical for nutrient absorption and defending against pathogen infection. Deoxynivalenol (Don), the most common mycotoxin, contaminates cereals and food throughout the world, causes serious damage to mammal intestinal mucosa, and appears as intestinal epithelial cell apoptosis and proliferation inhibition. Our previous study has found that milk-derived exosome ameliorates Don-induced intestinal damage, but the mechanism is still not fully understood. In this study, we demonstrated that Don downregulated the expression of miR-221/222 in intestinal epithelial cells, and exosome treatment reversed the inhibitory effect of Don on miR-221/222. Through immunofluorescence and flow cytometry analysis, we identified that miR-221/222 ameliorates Don-induced apoptosis and proliferation inhibition in intestinal epithelial cells. Through bioinformatics analyses and RNA immunoprecipitation analysis, we identified Phosphatase and tensin homolog (PTEN) is the target of miR-221/222. Through the PTEN interfering experiment, we found Don-induced apoptosis and proliferation inhibition relied on PTEN. Finally, through adenovirus to overexpress miR-221/222 in mice intestinal epithelial cells specifically, our results showed that miR-221/222 ameliorated Don-induced apoptosis and proliferation inhibition in intestinal epithelial cells by targeting PTEN. This study not only expands our understanding of how miR-221/222 and the host gene PTEN regulate intestinal epithelial cells defending against Don-induced damage, but also provides a new way to protect the development of the intestine.

Aldo-Keto Reductase 1C3 Mediates Chemotherapy Resistance in Esophageal Adenocarcinoma via ROS Detoxification

Simple Summary

The multidrug resistance of EAC is one of the major obstacles to chemotherapeutic efficiency. Our study aims to explore the molecular mechanism of AKR1C3 as a novel therapeutic target to overcome chemotherapy resistance for EAC patients. We demonstrate that AKR1C3 renders chemotherapy resistance through controlling cellular ROS levels via AKT signaling in EAC cells. Modulation of intracellular GSH levels by AKR1C3 could scavenge the intracellular ROS, thus regulating apoptosis. Targeting AKR1C3 may represent a novel strategy to sensitize EAC cells to conventional chemotherapy treatment and benefit the overall survival of patients diagnosed with EAC.

Abstract

Esophageal adenocarcinoma (EAC) is one of the most lethal malignancies, and limits promising treatments. AKR1C3 represents a therapeutic target to combat the resistance in many cancers. However, the molecular mechanism of AKR1C3 in the chemotherapy resistance of EAC is still unclear. We found that the mRNA level of AKR1C3 was higher in EAC tumor tissues, and that high AKR1C3 expression might be associated with poor overall survival of EAC patients. AKR1C3 overexpression decreased cell death induced by chemotherapeutics, while knockdown of AKR1C3 attenuated the effect. Furthermore, we found AKR1C3 was inversely correlated with ROS production. Antioxidant NAC rescued chemotherapy-induced apoptosis in AKR1C3 knockdown cells, while the GSH biosynthesis inhibitor BSO reversed a protective effect of AKR1C3 against chemotherapy. AKT phosphorylation was regulated by AKR1C3 and might be responsible for eliminating over-produced ROS in EAC cells. Intracellular GSH levels were modulated by AKR1C3 and the inhibition of AKT could reduce GSH level in EAC cells. Here, we reported for the first time that AKR1C3 renders chemotherapy resistance through controlling ROS levels via AKT signaling in EAC cells. Targeting AKR1C3 may represent a novel strategy to sensitize EAC cells to conventional chemotherapy.

LncRNA lnc-ISG20 promotes renal fibrosis in diabetic nephropathy by inducing AKT phosphorylation through miR-486-5p/NFAT5

Long non‐coding RNA (lncRNA) lnc‐ISG20 has been found aberrantly up‐regulated in the glomerular in the patients with diabetic nephropathy (DN). We aimed to elucidate the function and regulatory mechanism of lncRNA lnc‐ISG20 on DN‐induced renal fibrosis. Expression patterns of lnc‐ISG20 in kidney tissues of DN patients were determined by RT‐qPCR. Mouse models of DN were constructed, while MCs were cultured under normal glucose (NG)/high glucose (HG) conditions. The expression patterns of fibrosis marker proteins collagen IV, fibronectin and TGF‐β1 were measured with Western blot assay. In addition, the relationship among lnc‐ISG20, miR‐486‐5p, NFAT5 and AKT were analysed using dual‐luciferase reporter assay and RNA immunoprecipitation. The effect of lnc‐ISG20 and miR‐486/NFAT5/p‐AKT axis on DN‐associated renal fibrosis was also verified by means of rescue experiments. The expression levels of lnc‐ISG20 were increased in DN patients, DN mouse kidney tissues and HG‐treated MCs. Lnc‐ISG20 silencing alleviated HG‐induced fibrosis in MCs and delayed renal fibrosis in DN mice. Mechanistically, miR‐486‐5p was found to be a downstream miRNA of lnc‐ISG20, while miR‐486‐5p inhibited the expression of NFAT5 by binding to its 3'UTR. NFAT5 overexpression aggravated HG‐induced fibrosis by stimulating AKT phosphorylation. However, NFAT5 silencing reversed the promotion of in vitro and in vivo fibrosis caused by lnc‐ISG20 overexpression. Our collective findings indicate that lnc‐ISG20 promotes the renal fibrosis process in DN by activating AKT through the miR‐486‐5p/NFAT5 axis. High‐expression levels of lnc‐ISG20 may be a useful indicator for DN.

Recent Updates on the Involvement of PI3K/AKT/mTOR Molecular Cascade in the Pathogenesis of Hyperproliferative Skin Disorders

PhosphoInositide-3 Kinase (PI3K) represents a family of different classes of kinases which control multiple biological processes in mammalian cells, such as cell growth, proliferation, and survival. Class IA PI3Ks, the main regulators of proliferative signals, consists of a catalytic subunit (α, β, δ) that binds p85 regulatory subunit and mediates activation of AKT and mammalian Target Of Rapamycin (mTOR) pathways and regulation of downstream effectors. Dysregulation of PI3K/AKT/mTOR pathway in skin contributes to several pathological conditions characterized by uncontrolled proliferation, including skin cancers, psoriasis, and atopic dermatitis (AD). Among cutaneous cancers, basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC) display PI3K/AKT/mTOR signaling hyperactivation, implicated in hyperproliferation, and tumorigenesis, as well as in resistance to apoptosis. Upregulation of mTOR signaling proteins has also been reported in psoriasis, in association with enhanced proliferation, defective keratinocyte differentiation, senescence-like growth arrest, and resistance to apoptosis, accounting for major parts of the overall disease phenotypes. On the contrary, PI3K/AKT/mTOR role in AD is less characterized, even though recent evidence demonstrates the relevant function for mTOR pathway in the regulation of epidermal barrier formation and stratification. In this review, we provide the most recent updates on the role and function of PI3K/AKT/mTOR molecular axis in the pathogenesis of different hyperproliferative skin disorders, and highlights on the current status of preclinical and clinical studies on PI3K-targeted therapies.

OSU-03012 Disrupts Akt Signaling and Prevents Endometrial Carcinoma Progression in vitro and in vivo

Purpose

OSU-03012 is a celecoxib derivative lacking cyclooxygenase-2 inhibitory activity and a potent PDK1 inhibitor which has been shown to inhibit tumor growth in various ways. However, the role of OSU-03012 in endometrial carcinoma (EC) in which the PI3K/Akt signaling pathway highly activated has not been studied. Here, we determined the potency of OSU-03012 in suppressing EC progression in vitro and in vivo, and studied the underlined mechanisms.

Methods

The human EC Ishikawa and HEC-1A cells were used as the in vitro models. CCK8 assay and flow cytometry were conducted to evaluate cell proliferation, cell cycle progression, and apoptosis. The metastatic ability was evaluated using the transwell migration assay. The Ishikawa xenograft tumor model was used to study the inhibitory effects of OSU-03012 on EC growth in vivo. Western blot analysis was performed to evaluate expressions of the cell cycle and apoptosis associated proteins.

Results

OSU-03012 could inhibit the progression of EC both in vitro and in vivo by disrupting Akt signaling. It reduced the metastatic ability of EC, led to G2/M cell cycle arrest and induced apoptosis via the mitochondrial apoptosis pathway.

Conclusion

Our data indicated that OSU-03012 could inhibit the progression of EC in vitro and in vivo. It can potentially be used as the targeted drug for the treatment of EC by inhibiting Akt signaling.

Ginsenoside Rh1 Induces MCF-7 Cell Apoptosis and Autophagic Cell Death through ROS-Mediated Akt Signaling

Simple Summary

Breast cancer (BC) is the most common cause of cancer-related deaths among women worldwide, and its incidence has been increasing. However, current therapeutic approaches, such as chemotherapy, radiation, and hormonal therapy, have become increasingly ineffective because of their severe adverse effects and multidrug resistance. Therefore, the discovery of new potential candidates for BC therapy is essential. Here, we investigated whether ginsenoside Rh1 exhibits anticancer effects on BC. We found that this ginsenoside effectively inhibited the growth of BC cells in both cell cultures and mice. Therefore, ginsenoside Rh1 is a promising candidate for BC treatment.

Abstract

Breast cancer (BC) is the leading cause of cancer-related deaths among women worldwide. Ginsenosides exhibit anticancer activity against various cancer cells. However, the effects of ginsenoside Rh1 on BC and the underlying mechanisms remain unknown. Here, we investigated the anticancer effects of Rh1 on human BC MCF-7 and HCC1428 cells and the underlying signaling pathways. The anticancer effects of Rh1 in vitro were evaluated using sulforhodamine B (SRB), 3-(4, 5-dimethylthiazole-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), clonogenic assay, propidium iodide (PI)/Hoechst staining, Western blotting, flow cytometry, and immunofluorescence analysis. The in vivo effects of Rh1 were determined using a xenograft model via hematoxylin and eosin and the immunohistochemistry staining of tumor tissues. We found that Rh1 exerted cytotoxicity in the cells by increasing cell apoptosis, autophagy, and cell cycle arrest. These effects were further enhanced by a phosphatidylinositol 3-kinase (PI3K) inhibitor but were rescued by the inhibition of reactive oxygen species (ROS). Moreover, enhanced ROS generation by Rh1 inhibited the activation of the PI3K/Akt pathway. Consistently, Rh1 treatment significantly reduced tumor growth in vivo and increased the ROS production and protein expression of LC3B and cleaved caspase-3 but decreased the phosphorylation of Akt and retinoblastoma (Rb) in tumor tissues. Taken together, Rh1 exerted a potential anticancer effect on BC cells by inducing cell cycle arrest, apoptosis, and autophagy via inhibition of the ROS-mediated PI3K/Akt pathway.

AKT Inhibitors: The Road Ahead to Computational Modeling-Guided Discovery

AKT, is a serine/threonine protein kinase comprising three isoforms-namely: AKT1, AKT2 and AKT3, whose inhibitors have been recognized as promising therapeutic targets for various human disorders, especially cancer. In this work, we report a systematic evaluation of multi-target Quantitative Structure-Activity Relationship (mt-QSAR) models to probe AKT' inhibitory activity, based on different feature selection algorithms and machine learning tools. The best predictive linear and non-linear mt-QSAR models were found by the genetic algorithm-based linear discriminant analysis (GA-LDA) and gradient boosting (Xgboost) techniques, respectively, using a dataset containing 5523 inhibitors of the AKT isoforms assayed under various experimental conditions. The linear model highlighted the key structural attributes responsible for higher inhibitory activity whereas the non-linear model displayed an overall accuracy higher than 90%. Both these predictive models, generated through internal and external validation methods, were then used for screening the Asinex kinase inhibitor library to identify the most potential virtual hits as pan-AKT inhibitors. The virtual hits identified were then filtered by stepwise analyses based on reverse pharmacophore-mapping based prediction. Finally, results of molecular dynamics simulations were used to estimate the theoretical binding affinity of the selected virtual hits towards the three isoforms of enzyme AKT. Our computational findings thus provide important guidelines to facilitate the discovery of novel AKT inhibitors.

AKT-mediated regulation of chromatin ubiquitylation and tumorigenesis through Mel18 phosphorylation

Polycomb repressor complex 1 (PRC1) is linked to the regulation of gene expression and histone ubiquitylation conformation, which contributes to carcinogenesis. However, the upstream regulators of PRC1 biogenesis machinery remain obscure. Here, we report that the polycomb group-related mammalian gene Mel18 is a target of the protein kinase AKT. AKT phosphorylates Mel18 at T334 to disrupt the interaction between Mel18 and other PRC1 members, leading to attenuated PRC1-dependent ubiquitylation of histone H2A at Lys119. As such, PRC1 target genes, many of which are known oncogenes, are derepressed upon T334-Mel18 phosphorylation, which promotes malignant behaviours, including cell proliferation, tumour formation, migration and invasion, bone and brain metastatic lesion formation. Notably, a positive correlation between AKT activity and pT334-Mel18 is observed, and prognostic models based on p-AKT and pT334-Mel18 that predicted overall survival and distant metastasis-free survival in breast cancer patients are established. These findings have implications for understanding the role of AKT and its associated proteins in chromatin ubiquitylation, and also indicate the AKT-Mel18-H2AK119ub axis as a novel prognostic biomarker and therapeutic target for cancer patients.

Mechanisms of Resistance to PI3K Inhibitors in Cancer: Adaptive Responses, Drug Tolerance and Cellular Plasticity

The phosphatidylinositol-3-kinase (PI3K) pathway plays a central role in the regulation of several signalling cascades which regulate biological processes such as cellular growth, survival, proliferation, motility and angiogenesis. The hyperactivation of this pathway is linked to tumour progression and is one of the most common events in human cancers. Additionally, aberrant activation of the PI3K pathway has been demonstrated to limit the effectiveness of a number of anti-tumour agents paving the way for the development and implementation of PI3K inhibitors in the clinic. However, the overall effectiveness of these compounds has been greatly limited by inadequate target engagement due to reactivation of the pathway by compensatory mechanisms. Herein, we review the common adaptive responses that lead to reactivation of the PI3K pathway, therapy resistance and potential strategies to overcome these mechanisms of resistance. Furthermore, we highlight the potential role in changes in cellular plasticity and PI3K inhibitor resistance.

Resveratrol effects in bladder cancer: A mini review

Bladder cancer has a high incidence worldwide and is the most common genitourinary cancer. The treatment of bladder cancer involves surgery and chemotherapy; however high failure rates and toxicity are observed. In this context, the search of new drugs aiming a more effective treatment is extremely necessary. Natural products are an important source of compounds with antiproliferative effects. Resveratrol is a naturally occurring plant polyphenol whose anticancer activity has been demonstrated in different types of cancer. This review summarizes the in vitro and in vivo studies using models of bladder cancer treated with resveratrol and discusses its different mechanisms of action.

Onosma bracteata Wall. induces G0/G1 arrest and apoptosis in MG-63 human osteosarcoma cells via ROS generation and AKT/GSK3β/cyclin E pathway

Onosma bracteata Wall. (Boraginaceae), commonly known as "gaozaban" is a highly valuable medicinal herb, useful in the treatment of body swellings, abdominal pain, eye-related problems, fever, and urinary calculi. The present study was performed to investigate the antioxidant properties of extract/fractions, viz. ethanol (Obeth) extract, hexane (Obhex) fraction, chloroform (Obcl) fraction, ethyl acetate (Obea) fraction, butanol (Obbu) fraction, and aqueous (Obaq) fraction isolated from O. bracteata. Obea fraction showed stronger free radical quenching ability in various antioxidant assays, as compared to the other fractions. Obea fraction with effective free radical-scavenging properties was further evaluated for the antiproliferative activity against human osteosarcoma MG-63, human neuroblastoma IMR-32, and human lung cancer A549 cell lines using MTT assay. Obea fraction showed strong cytotoxicity with GI₅₀ value of 88.56, 101.61, and 112.7 μg/ml towards MG-63, IMR-32, and A549 cells respectively. Mechanistic studies revealed that Obea fraction in osteosarcoma MG-63 cells increased reactive oxygen species (ROS) level and reduced mitochondrial membrane potential. In the presence of Obea, the cells were found to be arrested in the G₀/G₁ phase in a dose-dependent manner which is also confirmed by the enhancement in the early apoptotic cell population in flow cytometer analysis. Western blotting demonstrated the decrease in expression of p-NFκB, COX-2, p-Akt, and Bcl-xL, whereas upregulation was observed in the expression of GSK-3β, p53, caspase-3, and caspase-9 proteins. RT-qPCR studies revealed downregulation of Bcl-2, cyclin E, CDK2, and mortalin gene expression and upregulation in the expression of p53 genes. The antioxidant and cytotoxic potential of Obea was attributed to the presence of catechin, kaempferol, onosmin A, and epicatechin, as revealed by HPLC analysis. This is the first report regarding the antiproliferative potential of O. bracteata against osteosarcoma.

Inhibition of PI3K Isoform p110γ Increases Both Anti-Tumor and Immunosuppressive Responses to Aggressive Murine Head and Neck Squamous Cell Carcinoma with Low Immunogenicity

Simple Summary

Poorly immunogenic head and neck squamous carcinomas (HNSCC) remain difficult to treat due to poor response rates to immunotherapy. Inhibition of the PI3K catalytic subunit p110γ, which is expressed in leukocytes and some HNSCCs, has shown promise in treating HNSCC; with clinical trials underway to gauge its effectiveness. However, the effect of PI3K p110γ inhibition on the host immune system in poorly immunogenic HNSCC has not been fully described. In this study, our group characterized the immune response to poorly immunogenic HNSCC in the absence of PI3K p110γ using an orthotopic mouse model with the MOC2 cell line. We found that mice lacking p110γ did not demonstrate significantly different tumor growth or metastasis, though we observed substantial elevation in both anti-tumor and immunosuppressive activity at the primary tumor site. Our results indicate that PI3K p110γ inhibition may potentially enhance anti-tumor immunity against poorly immunogenic HNSCC if administered with checkpoint inhibitors.

Abstract

HNSCC is the sixth most common cancer, with around 650,000 new cases yearly. Gain of function mutations in the PI3K pathway are common in HNSCC, and inhibition of the PI3K p110γ subunit has shown promise in HNSCC treatment. However, given that PI3K p110γ plays an important role in myeloid and lymphoid immune cell function, it is essential to understand how PI3K p110γ inhibition affects the anti-tumor immune response independent of tumor cells. To elucidate PI3K p110γ function in HNSCC, we employed an orthotopic mouse model using poorly immunogenic and aggressive cell line MOC2 on Pik3cg^−/− mice. We observed that wild-type and Pik3cg^−/− mice displayed similar rates of HNSCC tumor growth and metastasis after 20 days following tumor injection. T-cell infiltration and intrinsic T-cell responses to MOC2 oral tumors were comparable between wild-type and Pik3cg^−/− mice. Interestingly, the immune response of tumor-bearing Pik3cg^−/− mice was marked by increased anti-tumor cytotoxic molecules (IFN-γ, IL-17)) by T-cells and immune checkpoint marker (PD-L1, PD-1) expression by myeloid cells and T-cells compared to tumor-bearing wild-type mice. Taken together, our findings demonstrate that inhibition of PI3K p110γ modulates tumor-associated immune cells, which likely potentiates HNSCC treatment when used in combination with selective checkpoint inhibitors.

Pre-existing Cell States Control Heterogeneity of Both EGFR and CXCR4 Signaling

INTRODUCTION

CXCR4 and epidermal growth factor receptor (EGFR) represent two major families of receptors, G-protein coupled receptors and receptor tyrosine kinases, with central functions in cancer. While utilizing different upstream signaling molecules, both CXCR4 and EGFR activate kinases ERK and Akt, although single-cell activation of these kinases is markedly heterogeneous. One hypothesis regarding the origin of signaling heterogeneity proposes that intercellular variations arise from differences in pre-existing intracellular states set by extrinsic noise. While pre-existing cell states vary among cells, each pre-existing state defines deterministic signaling outputs to downstream effectors. Understanding causes of signaling heterogeneity will inform treatment of cancers with drugs targeting drivers of oncogenic signaling.

METHODS

We built a single-cell computational model to predict Akt and ERK responses to CXCR4- and EGFR-mediated stimulation. We investigated signaling heterogeneity through these receptors and tested model predictions using quantitative, live-cell time-lapse imaging.

RESULTS

We show that the pre-existing cell state predicts single-cell signaling through both CXCR4 and EGFR. Computational modeling reveals that the same set of pre-existing cell states explains signaling heterogeneity through both EGFR and CXCR4 at multiple doses of ligands and in two different breast cancer cell lines. The model also predicts how phosphatidylinositol-3-kinase (PI3K) targeted therapies potentiate ERK signaling in certain breast cancer cells and that low level, combined inhibition of MEK and PI3K ablates potentiated ERK signaling.

CONCLUSIONS

Our data demonstrate that a conserved motif exists for EGFR and CXCR4 signaling and suggest potential clinical utility of the computational model to optimize therapy.

Akt signaling is activated by TGFβ2 and impacts tenogenic induction of mesenchymal stem cells

Background

Tissue engineered and regenerative approaches for treating tendon injuries are challenged by the limited information on the cellular signaling pathways driving tenogenic differentiation of stem cells. Members of the transforming growth factor (TGF) β family, particularly TGFβ2, play a role in tenogenesis, which may proceed via Smad-mediated signaling. However, recent evidence suggests some aspects of tenogenesis may be independent of Smad signaling, and other pathways potentially involved in tenogenesis are understudied. Here, we examined the role of Akt/mTORC1/P70S6K signaling in early TGFβ2-induced tenogenesis of mesenchymal stem cells (MSCs) and evaluated TGFβ2-induced tenogenic differentiation when Smad3 is inhibited.

Methods

Mouse MSCs were treated with TGFβ2 to induce tenogenesis, and Akt or Smad3 signaling was chemically inhibited using the Akt inhibitor, MK-2206, or the Smad3 inhibitor, SIS3. Effects of TGFβ2 alone and in combination with these inhibitors on the activation of Akt signaling and its downstream targets mTOR and P70S6K were quantified using western blot analysis, and cell morphology was assessed using confocal microscopy. Levels of the tendon marker protein, tenomodulin, were also assessed.

Results

TGFβ2 alone activated Akt signaling during early tenogenic induction. Chemically inhibiting Akt prevented increases in tenomodulin and attenuated tenogenic morphology of the MSCs in response to TGFβ2. Chemically inhibiting Smad3 did not prevent tenogenesis, but appeared to accelerate it. MSCs treated with both TGFβ2 and SIS3 produced significantly higher levels of tenomodulin at 7 days and morphology appeared tenogenic, with localized cell alignment and elongation. Finally, inhibiting Smad3 did not appear to impact Akt signaling, suggesting that Akt may allow TGFβ2-induced tenogenesis to proceed during disruption of Smad3 signaling.

Conclusions

These findings show that Akt signaling plays a role in TGFβ2-induced tenogenesis and that tenogenesis of MSCs can be initiated by TGFβ2 during disruption of Smad3 signaling. These findings provide new insights into the signaling pathways that regulate tenogenic induction in stem cells.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-021-02167-2.

MicroRNA regulation of cancer stem cells in the pathogenesis of breast cancer

Breast cancer is the most common cancer among women and accounts for 30% of all female malignancies worldwide. Breast cancer stem cells (BCSCs) are a small population of breast cancer cells that exhibit multiple characteristics including differentiation capacity, self-renewal and therapeutic resistance. Recently, BCSCs have attracted attention due to their modulation of breast tumor behaviors and drug resistance. miRNAs are small noncoding mRNAs involved in virtually all biological processes, including stem cell development, maintenance and differentiation. In breast cancer, miRNAs appear to be multi-faceted since they can act as either suppressors or oncogenes to regulate breast cancer progression. This review summarizes the critical roles of miRNAs in regulating multiple signaling pathways such as Wnt/β-catenin, Notch, PI3K/AKT/mTOR, BMI-1 and STAT3 that are important for the BCSC maintenance.