FoxO3a transcriptional regulation of Bim controls apoptosis in paclitaxel-treated breast cancer cell lines

Acetylation of FOXO1 activates Bim expression involved in CVB3 induced cardiomyocyte apoptosis

Viral myocarditis (VMC) is the major reason for sudden cardiac death among both children and young adults. Of these, coxsackievirus B3 (CVB3) is the most common causative agent of myocarditis. Recently, the role of signaling pathways in the pathogenesis of VMC has been evaluated in several studies, which has provided a new perspective on identifying potential therapeutic targets for this hitherto incurable disease. In the present study, in vivo and in vitro experiments showed that CVB3 infection leads to increased Bim expression and triggers apoptosis. In addition, by knocking down Bim using RNAi, we further confirmed the biological function of Bim in apoptosis induced by CVB3 infection. We additionally found that Bim and forkhead box O1 class (FOXO1) inhibition significantly increased the viability of CVB3-infected cells while blocking viral replication and viral release. Moreover, CVB3-induced Bim expression was directly dependent on FOXO1 acetylation, which is catalyzed by the co-regulation of CBP and SirTs. Furthermore, the acetylation of FOXO1 was an important step in Bim activation and apoptosis induced by CVB3 infection. The findings of this study suggest that CVB3 infection induces apoptosis through the FOXO1 acetylation-Bim pathway, thus providing new insights for developing potential therapeutic targets for enteroviral myocarditis.

Investigating the mechanism of tricyclic decyl benzoxazole -induced apoptosis in liver Cancer cells through p300-mediated FOXO3 activation

OBJECTIVE

To investigate whether tricyclic decylbenzoxazole (TDB) regulates liver cancer cell proliferation and apoptosis through p300-mediated FOXO acetylation.

METHODS

Sequencing, adenovirus, and lentivirus transfection were performed in human liver cancer cell line SMMC-7721 and apoptosis was detected by Tunel, Hoechst, and flow cytometry. TEM for mitochondrial morphology, MTT for cell proliferation ability, Western blot, and PCR were used to detect protein levels and mRNA changes.

RESULTS

Sequencing analysis and cell experiments confirmed that TDB can promote the up-regulation of FOXO3 expression. TDB induced FOXO3 up-regulation in a dose-dependent manner, promoted the expression of p300 and Bim, and enhanced the acetylation and dephosphorylation of FOXO3, thus promoting apoptosis. p300 promotes apoptosis of cancer cells through Bim and other proteins, while HAT enhances the phosphorylation of FOXO3 and inhibits apoptosis. Overexpression of FOXO3 can increase the expression of exo-apoptotic pathways (FasL, TRAIL), endo-apoptotic pathways (Bim), and acetylation at the protein level and inhibit cell proliferation and apoptotic ability, while FOXO3 silencing or p300 mutation can partially reverse apoptosis. In tumor tissues with overexpression of FOXO3, TDB intervention can further increase the expression of p53 and caspase-9 proteins in tumor cells, resulting in loss of mitochondrial membrane integrity during apoptosis, the release of cytoplasm during signal transduction, activation of caspase-9 and synergistic inhibition of growth.

CONCLUSION

TDB induces proliferation inhibition and promotes apoptosis of SMMC-7721 cells by activating p300-mediated FOXO3 acetylation.

Unveiling the potential of FOXO3 in lung cancer: From molecular insights to therapeutic prospects

Lung cancer poses a significant challenge regarding molecular heterogeneity, as it encompasses a wide range of molecular alterations and cancer-related pathways. Recent discoveries made it feasible to thoroughly investigate the molecular mechanisms underlying lung cancer, giving rise to the possibility of novel therapeutic strategies relying on molecularly targeted drugs. In this context, forkhead box O3 (FOXO3), a member of forkhead transcription factors, has emerged as a crucial protein commonly dysregulated in cancer cells. The regulation of the FOXO3 in reacting to external stimuli plays a key role in maintaining cellular homeostasis as a component of the molecular machinery that determines whether cells will survive or dies. Indeed, various extrinsic cues regulate FOXO3, affecting its subcellular location and transcriptional activity. These regulations are mediated by diverse signaling pathways, non-coding RNAs (ncRNAs), and protein interactions that eventually drive post-transcriptional modification of FOXO3. Nevertheless, while it is no doubt that FOXO3 is implicated in numerous aspects of lung cancer, it is unclear whether they act as tumor suppressors, promotors, or both based on the situation. However, FOXO3 serves as an intriguing possible target in lung cancer therapeutics while widely used anti-cancer chemo drugs can regulate it. In this review, we describe a summary of recent findings on molecular mechanisms of FOXO3 to clarify that targeting its activity might hold promise in lung cancer treatment.

Epithelial-mesenchymal transition status is a remarkable biomarker for the combination treatment with avutometinib and defactinib in KRAS-mutated non-small cell lung cancer

BACKGROUND

Recent therapeutic strategies for KRAS-mutated cancers that inhibit the MAPK pathway have attracted considerable attention. The RAF/MEK clamp avutometinib (VS-6766/CH5126766/RO5126766/CKI27) is promising for patients with KRAS-mutated cancers. Although avutometinib monotherapy has shown clinical activity in patients with KRAS-mutated cancers, effective combination strategies will be important to develop.

METHODS

Using a phosphorylation kinase array kit, we explored the feedback mechanism of avutometinib in KRAS-mutated NSCLC cells, and investigated the efficacy of combining avutometinib with inhibitors of the feedback signal using in vitro and in vivo experiments. Moreover, we searched for a biomarker for the efficacy of combination therapy through an in vitro study and analysis using the The Cancer Genome Atlas Programme dataset.

RESULTS

Focal adhesion kinase (FAK) phosphorylation/activation was increased after avutometinib treatment and synergy between avutometinib and FAK inhibitor, defactinib, was observed in KRAS-mutated NSCLC cells with an epithelial rather than mesenchymal phenotype. Combination therapy with avutometinib and defactinib induced apoptosis with upregulation of Bim in cancer cells with an epithelial phenotype in an in vitro and in vivo study.

CONCLUSIONS

These results demonstrate that the epithelial-mesenchymal transition status may be a promising biomarker for the efficacy of combination therapy with avutometinib and defactinib in KRAS-mutated NSCLC.

Fbxo45 facilitates the malignant progression of breast cancer by targeting Bim for ubiquitination and degradation

BACKGROUND

Breast cancer is one of the common malignancies in women. Evidence has demonstrated that FBXO45 plays a pivotal role in oncogenesis and progression. However, the role of FBXO45 in breast tumorigenesis remains elusive. Exploration of the regulatory mechanisms of FBXO45 in breast cancer development is pivotal for potential therapeutic interventions in patients with breast cancer.

METHODS

Hence, we used numerous approaches to explore the functions of FBXO45 and its underlaying mechanisms in breast cancer pathogenesis, including CCK-8 assay, EdU assay, colony formation analysis, apoptosis assay, RT-PCR, Western blotting, immunoprecipitation, ubiquitination assay, and cycloheximide chase assay.

RESULTS

We found that downregulation of FBXO45 inhibited cell proliferation, while upregulation of FBXO45 elevated cell proliferation in breast cancer. Silencing of FBXO45 induced cell apoptosis, whereas overexpression of FBXO45 inhibited cell apoptosis in breast cancer. Moreover, FBXO45 interacted with BIM and regulated its ubiquitination and degradation. Furthermore, knockdown of FBXO45 inhibited cell proliferation via regulation of BIM pathway. Notably, overexpression of FBXO45 facilitated tumor growth in mice. Strikingly, FBXO45 expression was associated with poor survival of breast cancer patients.

CONCLUSION

Our study could provide the rational for targeting FBXO45 to obtain benefit for breast cancer patients. Altogether, modulating FBXO45/Bim axis could be a promising strategy for breast cancer therapy.

Role and regulation of FOXO3a: new insights into breast cancer therapy

Breast cancer is the most common malignancy in the world, particularly affecting female cancer patients. Enhancing the therapeutic strategies for breast cancer necessitates identifying molecular drug targets that effectively eliminate tumor cells. One of these prominent targets is the forkhead and O3a class (FOXO3a), a member of the forkhead transcription factor subfamily. FOXO3a plays a pivotal role in various cellular processes, including apoptosis, proliferation, cell cycle regulation, and drug resistance. It acts as a tumor suppressor in multiple cancer types, although its specific role in cancer remains unclear. Moreover, FOXO3a shows promise as a potential marker for tumor diagnosis and prognosis in breast cancer patients. In addition, it is actively influenced by common anti-breast cancer drugs like paclitaxel, simvastatin, and gefitinib. In breast cancer, the regulation of FOXO3a involves intricate networks, encompassing post-translational modification post-translational regulation by non-coding RNA (ncRNA) and protein-protein interaction. The specific mechanism of FOXO3a in breast cancer urgently requires further investigation. This review aims to systematically elucidate the role of FOXO3a in breast cancer. Additionally, it reviews the interaction of FOXO3a and its upstream and downstream signaling pathway-related molecules to uncover potential therapeutic drugs and related regulatory factors for breast cancer treatment by regulating FOXO3a.

Curcumin and its Derivatives Targeting Multiple Signaling Pathways to Elicit Anticancer Activity: A Comprehensive Perspective

The uncontrolled growth and spread of aberrant cells characterize the group of disorders known as cancer. According to GLOBOCAN 2022 analysis of cancer patients in either developed countries or developing countries the main concern cancers are breast cancer, lung cancer, and liver cancer which may rise eventually. Natural substances with dietary origins have gained interest for their low toxicity, anti-inflammatory, and antioxidant effects. The evaluation of dietary natural products as chemopreventive and therapeutic agents, the identification, characterization, and synthesis of their active components, as well as the enhancement of their delivery and bioavailability, have all received significant attention. Thus, the treatment strategy for concerning cancers must be significantly evaluated and may include the use of phytochemicals in daily lifestyle. In the present perspective, we discussed one of the potent phytochemicals, that has been used over the past few decades known as curcumin as a panacea drug of the "Cure-all" therapy concept. In our review firstly we included exhausted data from in vivo and in vitro studies on breast cancer, lung cancer, and liver cancer which act through various cancer-targeting pathways at the molecular level. Now, the second is the active constituent of turmeric known as curcumin and its derivatives are enlisted with their targeted protein in the molecular docking studies, which help the researchers design and synthesize new curcumin derivatives with respective implicated molecular and cellular activity. However, curcumin and its substituted derivatives still need to be investigated with unknown targeting mechanism studies in depth.

Harmine Hydrochloride Induces G2/M Cell Cycle Arrest and Apoptosis in SK-Hep1 Hepatocellular Carcinoma Cells by Regulating Mitogen-Activated Protein Kinases and the PI3K/AKT Pathway

Liver cancer is a globally common form of cancer. Thus, novel drugs derived from natural products are needed to reduce the side effects of chemotherapy. The present study aimed to analyze the anticancer properties and effects of harmine hydrochloride (HMH), a water-soluble metabolite of harmine that can be easily absorbed into tissues, in treating liver cancer cells. HMH dose-dependently inhibited cell growth, migration, invasion, and colony formation in SK-Hep1 cells. It also induced G2/M arrest by reducing the expression of p-cdc2, cyclin B1, and Rb (G2/M phase regulatory proteins) in a dose-dependent manner. HMH treatment reduced the expression of caspase-9, caspase-3, PARP, and Bcl-2 and increased the expression of Bax (a proapoptotic protein). Moreover, it increased the production of reactive oxygen species and decreased the intracellular uptake of rhodamine 123 due to mitochondrial dysfunction because of oxidative stress. HMH treatment also upregulated the phosphorylation of JNK, p38, and FOXO3a in SK-Hep1 cells and downregulated the PI3K/AKT signaling pathway. Our findings suggest that HMH may activate the compounds responsible for anticancer effects in hepatocellular carcinoma cells.

Induction of Hepatocellular Carcinoma Cell Cycle Arrest and Apoptosis by Dendropanax morbifera Leveille Leaf Extract via the PI3K/AKT/mTOR Pathway

Liver cancer is prevalent worldwide and associated with a high mortality rate. Therefore, developing novel drugs derived from natural products to reduce the side effects of chemotherapy is urgently needed. In this study, the inhibitory effect of Dendropanax morbifera Leveille extract (DME) on growth of hepatocellular carcinoma (HCC) cells and its underlying mechanisms were investigated. DME suppressed the growth, migration, and invasion of SK-Hep1 human HCC cells. It also reduced the expression of the G0/G1 phase regulator proteins cyclin-dependent kinase (CDK) 4, cyclin D, CDK2, and cyclin E, thereby inducing G0/G1 arrest. Moreover, DME treatment reduced the expression of antiapoptotic proteins, including caspase-9, caspase-3, PARP, and Bcl-2 and increased the expression of the proapoptotic protein, Bax. DME also increased reactive oxygen species production and reduced the cellular uptake of rhodamine 123. DME treatment increased the levels of p-p38 and p-FOXO3a in a dose-dependent manner and decreased those of p-PI3K, p-AKT, p-mTOR, and p-p70 in SK-Hep1 cells. In addition, combined treatment with DME and LY294002, an AKT inhibitor, significantly reduced p-AKT levels. In summary, these results show that the PI3K/AKT/mTOR signaling pathway is involved in DME-mediated inhibition of proliferation, migration, and invasiveness, and induction of apoptosis of HCC cells.

Molecular analysis of XPO1 inhibitor and gemcitabine-nab-paclitaxel combination in KPC pancreatic cancer mouse model

BACKGROUND

The majority of pancreatic ductal adenocarcinoma (PDAC) patients experience disease progression while on treatment with gemcitabine and nanoparticle albumin-bound (nab)-paclitaxel (GemPac) necessitating the need for a more effective treatment strategy for this refractory disease. Previously, we have demonstrated that nuclear exporter protein exportin 1 (XPO1) is a valid therapeutic target in PDAC, and the selective inhibitor of nuclear export selinexor (Sel) synergistically enhances the efficacy of GemPac in pancreatic cancer cells, spheroids and patient-derived tumours, and had promising activity in a phase I study.

METHODS

Here, we investigated the impact of selinexor-gemcitabine-nab-paclitaxel (Sel-GemPac) combination on LSL-KrasG12D/+ ; LSL-Trp53R172H/+ ; Pdx1-Cre (KPC) mouse model utilising digital spatial profiling (DSP) and single nuclear RNA sequencing (snRNAseq).

RESULTS

Sel-GemPac synergistically inhibited the growth of the KPC tumour-derived cell line. The Sel-GemPac combination reduced the 2D colony formation and 3D spheroid formation. In the KPC mouse model, at a sub-maximum tolerated dose (sub-MTD) , Sel-GemPac enhanced the survival of treated mice compared to controls (p < .05). Immunohistochemical analysis of residual KPC tumours showed re-organisation of tumour stromal architecture, suppression of proliferation and nuclear retention of tumour suppressors, such as Forkhead Box O3a (FOXO3a). DSP revealed the downregulation of tumour promoting genes such as chitinase-like protein 3 (CHIL3/CHI3L3/YM1) and multiple pathways including phosphatidylinositol 3'-kinase-Akt (PI3K-AKT) signalling. The snRNAseq demonstrated a significant loss of cellular clusters in the Sel-GemPac-treated mice tumours including the CD44+ stem cell population.

CONCLUSION

Taken together, these results demonstrate that the Sel-GemPac treatment caused broad perturbation of PDAC-supporting signalling networks in the KPC mouse model.

HIGHLIGHTS

The majority of pancreatic ductal adenocarcinoma (PDAC) patients experience disease progression while on treatment with gemcitabine and nanoparticle albumin-bound (nab)-paclitaxel (GemPac). Exporter protein exportin 1 (XPO1) inhibitor selinexor (Sel) with GemPac synergistically inhibited the growth of LSL-KrasG12D/+; LSL-Trp53R172H/+; Pdx1-Cre (KPC) mouse derived cell line and enhanced the survival of mice. Digital spatial profiling shows that Sel-GemPac causes broad perturbation of PDAC-supporting signalling in the KPC model.

Role of forkhead box proteins in regulation of doxorubicin and paclitaxel responses in tumor cells: A comprehensive review

Chemotherapy is one of the common first-line therapeutic methods in cancer patients. Despite the significant effects in improving the quality of life and survival of patients, chemo resistance is observed in a significant part of cancer patients, which leads to tumor recurrence and metastasis. Doxorubicin (DOX) and paclitaxel (PTX) are used as the first-line drugs in a wide range of tumors; however, DOX/PTX resistance limits their use in cancer patients. Considering the DOX/PTX side effects in normal tissues, identification of DOX/PTX resistant cancer patients is required to choose the most efficient therapeutic strategy for these patients. Investigating the molecular mechanisms involved in DOX/PTX response can help to improve the prognosis in cancer patients. Several cellular processes such as drug efflux, autophagy, and DNA repair are associated with chemo resistance that can be regulated by transcription factors as the main effectors in signaling pathways. Forkhead box (FOX) family of transcription factor has a key role in regulating cellular processes such as cell differentiation, migration, apoptosis, and proliferation. FOX deregulations have been associated with resistance to chemotherapy in different cancers. Therefore, we discussed the role of FOX protein family in DOX/PTX response. It has been reported that FOX proteins are mainly involved in DOX/PTX response by regulation of drug efflux, autophagy, structural proteins, and signaling pathways such as PI3K/AKT, NF-kb, and JNK. This review is an effective step in introducing the FOX protein family as the reliable prognostic markers and therapeutic targets in cancer patients.

Pictilisib-Induced Resistance Is Mediated through FOXO1-Dependent Activation of Receptor Tyrosine Kinases in Mucinous Colorectal Adenocarcinoma Cells

The phosphatidylinositol (PI3K)/AKT/mTOR axis represents an important therapeutic target to treat human cancers. A well-described downstream target of the PI3K pathway is the forkhead box O (FOXO) transcription factor family. FOXOs have been implicated in many cellular responses, including drug-induced resistance in cancer cells. However, FOXO-dependent acute phase resistance mediated by pictilisib, a potent small molecule PI3K inhibitor (PI3Ki), has not been studied. Here, we report that pictilisib-induced adaptive resistance is regulated by the FOXO-dependent rebound activity of receptor tyrosine kinases (RTKs) in mucinous colorectal adenocarcinoma (MCA) cells. The resistance mediated by PI3K inhibition involves the nuclear localization of FOXO and the altered expression of RTKs, including ErbB2, ErbB3, EphA7, EphA10, IR, and IGF-R1 in MCA cells. Further, in the presence of FOXO siRNA, the pictilisib-induced feedback activation of RTK regulators (pERK and pAKT) was altered in MCA cells. Interestingly, the combinational treatment of pictilisib (Pi3Ki) and FOXO1i (AS1842856) synergistically reduced MCA cell viability and increased apoptosis. These results demonstrate that pictilisib used as a single agent induces acute resistance, partly through FOXO1 inhibition. Therefore, overcoming PI3Ki single-agent adaptive resistance by rational design of FOXO1 and PI3K inhibitor combinations could significantly enhance the therapeutic efficacy of PI3K-targeting drugs in MCA cells.

Pan-cancer analyses reveal multi-omic signatures and clinical implementations of the forkhead-box gene family

BACKGROUND

Forkhead box (FOX) proteins belong to one of the largest transcription factor families and play crucial roles in the initiation and progression of cancer. Prior research has linked several FOX genes, such as FOXA1 and FOXM1, to the crucial process of carcinogenesis. However, the overall picture of FOX gene family across human cancers is far from clear.

METHODS

To investigate the broad molecular signatures of the FOX gene family, we conducted study on multi-omics data (including genomics, epigenomics and transcriptomics) from over 11,000 patients with 33 different types of human cancers.

RESULTS

Pan-cancer analysis reveals that FOX gene mutations were found in 17.4% of tumor patients with a substantial cancer type-dependent pattern. Additionally, high expression heterogeneity of FOX genes across cancer types was discovered, which can be partially attributed to the genomic or epigenomic alteration. Co-expression network analysis reveals that FOX genes may exert functions by regulating the expression of both their own and target genes. For a clinical standpoint, we provided 103 FOX gene-drug target-drug predictions and found FOX gene expression have potential survival predictive value. All of the results have been included in the FOX2Cancer database, which is freely accessible at http://hainmu-biobigdata.com/FOX2Cancer.

CONCLUSION

Our findings may provide a better understanding of roles FOX genes played in the development of tumors, and help to offer new avenues for uncovering tumorigenesis and unprecedented therapeutic targets.

Evaluation of the Potential Diagnostic Role of the Lnc-MIAT, miR-29a-3p, and FOXO3a ceRNA Networks as Noninvasive Circulatory Bioindicator in Ductal Carcinoma Breast Cancer

Background

Over the last few decades, tremendous progress has been achieved in the early detection and treatment of breast cancer (BC). However, the prognosis remains unsatisfactory, and the underlying processes of carcinogenesis are still unclear. The purpose of this research was to find out the relationship between myocardial infarction-associated transcript (MIAT), FOXO3a, and miRNA29a-3p and evaluated the expression levels in patients compare with control and their potential as a noninvasive bioindicator in whole blood in BC.

Methods

Whole blood and BC tissue are taken from patients before radiotherapy and chemotherapy. Total RNA was extracted from BC tissue and whole blood to synthesize complementary DNA (cDNA). The expression of MIAT, FOXO3a, and miRNA29a-3p was analyzed by the quantitative reverse transcription-polymerase chain reaction (RT-qPCR) method and the sensitivity and specificity of them were determined by the receiver operating characteristic (ROC) curve. Bioinformatics analysis was used to understand the connections between MIAT, FOXO3a, and miRNA29a-3p in human BC to develop a ceRNA (competitive endogenous RNA) network.

Results

We identified that in ductal carcinoma BC tissue and whole blood, MIAT and FOXO3a were more highly expressed, whereas miRNA29a-3p was lower compared with those in nontumor samples. There was a positive correlation between the expression levels of MIAT, FOXO3a, and miRNA29a-3p in BC tissues and whole blood. Our results also proposed miRNA29a-3p as a common target between MIAT and FOXO3a, and we showed them as a ceRNA network.

Conclusions

This is the first study that indicates MIAT, FOXO3a, and miRNA29a-3p as a ceRNA network, and their expression was analyzed in both BC tissue and whole blood. As a preliminary assessment, our findings indicate that combined levels of MIAT, FOXO3a, and miR29a-3p may be considered as potential diagnostic bioindicator for BC.

FoxO3 and oxidative stress: a multifaceted role in cellular adaptation

Oxidative stress is a major cause of morbidity and mortality in human health and disease. In this review, we focus on the Forkhead Box (Fox) subclass O3 (FoxO3), an extensively studied transcription factor that plays a pleiotropic role in a wide range of physiological and pathological processes by regulating multiple gene regulatory networks involved in the modulation of numerous aspects of cellular metabolism, including fuel metabolism, cell death, and stress resistance. This review will also focus on regulatory mechanisms of FoxO3 expression and activity, such as crucial post-translational modifications and non-coding RNAs. Moreover, this work discusses and evidences some pathways to how this transcription factor and reactive oxygen species regulate each other, which may lead to the pathogenesis of various types of diseases. Therefore, in addition to being a promising therapeutic target, the FoxO3-regulated signaling pathways can also be used as reliable diagnostic and prognostic biomarkers and indicators for drug responsiveness.

The CNS-penetrating taxane drug TPI 287 potentiates antiglioma activity of the AURKA inhibitor alisertib in vivo

INTRODUCTION

Glioblastoma (GBM) has a very poor prognosis despite current treatment. We previously found cytotoxic synergy between the AURKA inhibitor alisertib and the CNS-penetrating taxane TPI 287 against GBM tumor cells in vitro.

METHODS

We used an orthotopic human GBM xenograft mouse model to test if TPI 287 potentiates alisertib in vivo. Western blotting, immunohistochemistry, siRNA knockdown, annexin V binding, and 3-dimensional Matrigel invasion assays were used to investigate potential mechanisms of alisertib and TPI 287 treatment interactions.

RESULTS

Alisertib + TPI 287 combination therapy significantly prolonged animal survival compared to vehicle (p = 0.011), but only marginally compared to alisertib alone. Alisertib, TPI 287, and combined alisertib + TPI 287 reduced animal tumor volume compared to vehicle-treated controls. This was statistically significant for the combination therapy at 4 weeks (p < 0.0001). Alisertib + TPI 287 treatment decreased anti-apoptotic Bcl-2 protein levels in vivo and in vitro. Expression of the pro-apoptotic protein Bak was significantly increased by combination treatment (p < 0.0001). Pro-apoptotic Bim and Bak knockdown by siRNA decreased apoptosis by alisertib + TPI 287 in GB9, GB30, and U87 cells (p = 0.0005 to 0.0381). Although alisertib and TPI 287 significantly reduced GBM cell invasion (p < 0.0001), their combination was no more effective than TPI 287 alone.

CONCLUSIONS

Results suggest that apoptosis is the dominant mechanism of potentiation of GBM growth inhibition by alisertib + TPI 287, in part through effects on Bcl-2 family proteins, providing a rationale for further laboratory testing of an AURKA inhibitor plus TPI 287 as a potential therapy against GBM.

Effect of intraperitoneal docetaxel on ovarian function in mice

Taxanes are important chemotherapeutic agents used to manage breast cancer and gynaecological malignancies. However, ovarian toxicity induced by the taxane docetaxel (DOC) is of great concern. We investigated DOC-induced toxicity in the ovaries of female CD1 strain mice. The mice were divided into control (saline), DOC-5 (5 mg/kg DOC), and DOC-10 (10 mg/kg DOC) groups and administered saline or DOC on the first day of the study and two weeks later. Two weeks after the second dose, the ovaries were removed for analysis after inducing superovulation. Ovary weight, the number of secondary follicles, and the total number of follicles were reduced after DOC administration. Additionally, the expression levels of caspase-3 and the pro-apoptotic protein Bcl-2 interacting mediator of cell death (BIM) increased. Our findings suggest that high-dose DOC induces damage to growing follicles; however, it may not affect primordial follicles.Impact statementWhat is already known on this subject? Docetaxel (DOC) is one of the most effective chemotherapeutic agents used to manage various cancers. Some in-vitro studies have examined paclitaxel-induced ovarian toxicity; however, limited research on DOC is available.What do the results of this study add? We investigated DOC-induced ovarian toxicity in female CD1 strain mice at 5 mg/kg and 10 mg/kg. We found that DOC reduced ovary weight, the number of secondary follicles, and the total number of follicles, with the higher dose having a higher effect.What are the implications of these findings for clinical practice and/or further research? We believe that our study makes a significant contribution to the knowledge about the effect of DOC on ovarian function.

HRK inhibits colorectal cancer cells proliferation by suppressing the PI3K/AKT/mTOR pathway

Background

As one of the most common malignant tumor, colorectal cancer (CRC) continues to have a high incidence and mortality rate. HRK belongs to the BCL-2 protein family, which has been shown to have antitumor effects in prostate cancer. However, its role in colorectal cancer is not yet known.

Methods

In this study, we verified the expression levels of HRK in colorectal cancer tissues by public database search as well as immunohistochemistry. Next, we analyzed HRK expression levels in CRC tissues,adjacent non-cancerous tissues, cell lines and normal intestinal epithelial cells by qPCR and Western blotting. CCK-8 proliferation assays, transwell assays, wound healing assays, colony assays and flow cytometry were performed to clarified the effect of HRK on CRC cells. Western blotting and rescue experiments were used to determine the role of HRK in regulating PI3K/AKT/mTOR signaling pathway.

Results

HRK expression was lower in CRC tissues and cell lines. Gain and loss of function experiments showed that HRK decreased proliferation, invasion and migration of CRC cells. Low expression of HRK inhibited CRC cell apoptosis as well as activated the PI3K/AKT/mTOR signaling pathway. In addition, rapamycin inhibits the activation of PI3K/AKT/mTOR signaling pathway and reverses HRK-induced alterations in cell biological functions.

Conclusion

Our study demonstrates that HRK is lowly expressed in colorectal cancer tissues. And for the first time, HRK was shown to promote apoptosis and inhibit proliferation of colorectal cancer cells by inhibiting PI3K/AKT/mTOR signaling pathway. HRK represents a potential target for the treatment of CRC.

Recent Developments and Anticancer Therapeutics of Paclitaxel: An Update

Plants are a source of diverse classes of secondary metabolites with anticancer properties. Paclitaxel (Taxol) is an anticancer drug isolated from various Taxus species and is used as a chemotherapeutic agent against various cancers. The biosynthesis of paclitaxel is a complex pathway, making its total chemical synthesis commercially non-viable; hence, alternative novel sources - like plant cell culture and heterologous expression systems, are being investigated to overcome this issue. Advancements in the field of genetic engineering, microbial fermentation engineering, and recombinant techniques have significantly increased the achievable yields of paclitaxel. Indeed, paclitaxel selectively targets microtubules and causes cell cycle arrest in the G2/M phase, inducing a cytotoxic effect in a concentration and time-dependent manner. Innovative drug delivery formulations, like the development of albumin-bound nanoparticles, nano-emulsions, nano-suspensions, liposomes, and polymeric micelles, have been applied to enhance the delivery of paclitaxel to tumor cells. This review focuses on the production, biosynthesis, mechanism of action, and anticancer effects of paclitaxel.

Phenanthroindolizidine Alkaloids Isolated from Tylophora ovata as Potent Inhibitors of Inflammation, Spheroid Growth, and Invasion of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC), representing the most aggressive form of breast cancer with currently no targeted therapy available, is characterized by an inflammatory and hypoxic tumor microenvironment. To date, a broad spectrum of anti-tumor activities has been reported for phenanthroindolizidine alkaloids (PAs), however, their mode of action in TNBC remains elusive. Thus, we investigated six naturally occurring PAs extracted from the plant Tylophora ovata: O-methyltylophorinidine (1) and its five derivatives tylophorinidine (2), tylophoridicine E (3), 2-demethoxytylophorine (4), tylophoridicine D (5), and anhydrodehydrotylophorinidine (6). In comparison to natural (1) and for more-in depth studies, we also utilized a sample of synthetic O-methyltylophorinidine (1s). Our results indicate a remarkably effective blockade of nuclear factor kappa B (NFκB) within 2 h for compounds (1) and (1s) (IC50 = 17.1 ± 2.0 nM and 3.3 ± 0.2 nM) that is different from its effect on cell viability within 24 h (IC50 = 13.6 ± 0.4 nM and 4.2 ± 1 nM). Furthermore, NFκB inhibition data for the additional five analogues indicate a structure–activity relationship (SAR). Mechanistically, NFκB is significantly blocked through the stabilization of its inhibitor protein kappa B alpha (IκBα) under normoxic as well as hypoxic conditions. To better mimic the TNBC microenvironment in vitro, we established a 3D co-culture by combining the human TNBC cell line MDA-MB-231 with primary murine cancer-associated fibroblasts (CAF) and type I collagen. Compound (1) demonstrates superiority against the therapeutic gold standard paclitaxel by diminishing spheroid growth by 40% at 100 nM. The anti-proliferative effect of (1s) is distinct from paclitaxel in that it arrests the cell cycle at the G0/G1 state, thereby mediating a time-dependent delay in cell cycle progression. Furthermore, (1s) inhibited invasion of TNBC monoculture spheroids into a matrigel®-based environment at 10 nM. In conclusion, PAs serve as promising agents with presumably multiple target sites to combat inflammatory and hypoxia-driven cancer, such as TNBC, with a different mode of action than the currently applied chemotherapeutic drugs.

Natural Compounds for SIRT1-Mediated Oxidative Stress and Neuroinflammation in Stroke: A Potential Therapeutic Target in the Future

Stroke is a fatal cerebral vascular disease with a high mortality rate and substantial economic and social costs. ROS production and neuroinflammation have been implicated in both hemorrhagic and ischemic stroke and have the most critical effects on subsequent brain injury. SIRT1, a member of the sirtuin family, plays a crucial role in modulating a wide range of physiological processes, including apoptosis, DNA repair, inflammatory response, and oxidative stress. Targeting SIRT1 to reduce ROS and neuroinflammation might represent an emerging therapeutic target for stroke. Therefore, we conducted the present review to summarize the mechanisms of SIRT1-mediated oxidative stress and neuroinflammation in stroke. In addition, we provide a comprehensive introduction to the effect of compounds and natural drugs on SIRT1 signaling related to oxidative stress and neuroinflammation in stroke. We believe that our work will be helpful to further understand the critical role of the SIRT1 signaling pathway and will provide novel therapeutic potential for stroke treatment.

TF-DUBTACs Stabilize Tumor Suppressor Transcription Factors

Targeted protein degradation approaches have been widely used for degrading oncogenic proteins, providing a potentially promising therapeutic strategy for cancer treatment. However, approaches to targeting tumor suppressor proteins are very limited, and only a few agonists have been developed to date. Here, we report the development of a platform termed TF-DUBTAC, which links a DNA oligonucleotide to a covalent ligand of the deubiquitinase OTUB1 via a click reaction, to selectively stabilize tumor suppressor transcription factors. We developed three series of TF-DUBTACs, namely, FOXO-DUBTAC, p53-DUBTAC, and IRF-DUBTAC, which stabilize FOXO3A, p53, and IRF3 in cells, respectively, in an OTUB1-dependent manner. These results suggest that TF-DUBTAC is a generalizable platform to achieve selective stabilization of tumor suppressor transcription factors as a therapeutic means to suppress tumorigenesis.

The antidepressant imipramine inhibits breast cancer growth by targeting estrogen receptor signaling and DNA repair events

Aberrant activities of various cell cycle and DNA repair proteins promote cancer growth and progression and render them resistant to therapies. Here, we demonstrate that the anti-depressant imipramine blocks growth of triple-negative (TNBC) and estrogen receptor-positive (ER+) breast cancers by inducing cell cycle arrest and by blocking heightened homologous recombination (HR) and non-homologous end joining-mediated (NHEJ) DNA repair activities. Our results reveal that imipramine inhibits the expression of several cell cycle- and DNA repair-associated proteins including E2F1, CDK1, Cyclin D1, and RAD51. In addition, we show that imipramine inhibits the growth of ER + breast cancers by inhibiting the estrogen receptor- α (ER-α) signaling. Our studies in preclinical mouse models and ex vivo explants from breast cancer patients show that imipramine sensitizes TNBC to the PARP inhibitor olaparib and endocrine resistant ER + breast cancer to anti-estrogens. Our studies suggest that repurposing imipramine could enhance routine care for breast cancer patients. Based on these results, we designed an ongoing clinical trial, where we are testing the efficacy of imipramine for treating patients with triple-negative and estrogen receptor-positive breast cancer. Since aberrant DNA repair activity is used by many cancers to survive and become resistant to therapy, imipramine could be used alone and/or with currently used drugs for treating many aggressive cancers.

Erythropoietin regulates signaling pathways associated with neuroprotective events

Erythropoietin is a cytokine that binds to the Erythropoietin receptor and regulates the formation of erythroid cells during erythropoiesis in the bone marrow. However, many other organs and tissues express Erythropoietin and its receptor, such as the Nervous System, which principally regulates tissue protection. In the Central Nervous System, Erythropoietin is principally expressed by astrocytes, while neurons mainly express Erythropoietin receptors. Moreover, Erythropoietin acts as a pleiotropic molecule with neuroprotective effects, and its mechanisms of signal transduction pathways are defined, and there is a growing interest in its therapeutic potential. This review focuses on the role of Erythropoietin and its relationship with HIF1, PI3/Akt, GSK3B, JAK/STAT, and MAPKs signaling pathways that leads to cell survival after injury in the Central Nervous System. Knowledge of these signaling systems comprehensively could better guide EPO treatment to restoring different SNC alterations mediated by different insults.

Comprehensive review on signaling pathways of dietary saponins in cancer cells suppression

Nutrigenomics utilizes high-throughput genomic technologies to reveal changes in gene and protein levels. Excitingly, ever-growing body of scientific findings has provided sufficient evidence about the interplay between diet and genes. Cutting-edge research and advancements in genomics, epigenetics and metabolomics have deepened our understanding on the role of dietary factors in the inhibition of carcinogenesis and metastasis. Dietary saponins, a type of triterpene glycosides, are generally found in Platycodon grandifloras, Dioscorea oppositifolia, asparagus, legumes, and sea cucumber. Wealth of information has started to shed light on pleiotropic mechanistic roles of dietary saponins in cancer prevention and inhibition. In this review, we have attempted to summarize the in vitro research of dietary saponins in the last two decades by searching common databases such as Google Scholar, PubMed, Scopus, and Web of Science. The results showed that dietary saponins exerted anti-cancer activities via regulation of apoptosis, autophagy, arrest cell cycle, anti-proliferation, anti-metastasis, and anti-angiogenesis, by regulation of several critical signaling pathways, including MAPK, PI3K/Akt/mTOR, NF-κB, and VEGF/VEGFR. However, there is no data about the dosage of dietary saponins for practical anti-cancer effects in human bodies. Extensive clinical studies are needed to confirm the effectiveness of dietary saponins for further commercial and medical applications.

Harmine Hydrochloride Mediates the Induction of G2/M Cell Cycle Arrest in Breast Cancer Cells by Regulating the MAPKs and AKT/FOXO3a Signaling Pathways

Breast cancer (BC) is one of the most common causes of death among women worldwide. Recently, interest in novel approaches for BC has increased by developing new drugs derived from natural products with reduced side effects. This study aimed to treat BC cells with harmine hydrochloride (HMH) to identify its anticancer effects and mechanisms. HMH treatment suppressed cell growth, migration, invasion, and colony formation in MCF-7 and MDA-MB-231 cells, regardless of the hormone signaling. It also reduced the phosphorylation of PI3K, AKT, and mTOR and increased FOXO3a expression. Additionally, HMH treatment increased p38 phosphorylation in MCF-7 cells and activated c-Jun N-terminal kinase (JNK) phosphorylation in MDA-MB-231 cells in a dose-dependent manner, where activated p38 and JNK increased FOXO3a expression. Activated FOXO3a increased the expression of p53, p21, and their downstream proteins, including p-cdc25, p-cdc2, and cyclin B1, to induce G2/M cell cycle arrest. Furthermore, HMH inhibited the PI3K/AKT/mTOR pathway by significantly reducing p-AKT expression in combination with LY294002, an AKT inhibitor. These results indicate that mitogen-activated protein kinases (MAPKs) and AKT/FOXO3a signaling pathways mediate the induction of cell cycle arrest following HMH treatment. Therefore, HMH could be a potential active compound for anticancer bioactivity in BC cells.

Constitutive BAK/MCL1 complexes predict paclitaxel and S63845 sensitivity of ovarian cancer

We previously found that preformed complexes of BAK with antiapoptotic BCL2 proteins predict BH3 mimetic sensitivities in lymphohematopoietic cells. These complexes have not previously been examined in solid tumors or in the context of conventional anticancer drugs. Here we show the relative amount of BAK found in preformed complexes with MCL1 or BCLXL varies across ovarian cancer cell lines and patient-derived xenografts (PDXs). Cells bearing BAK/MCL1 complexes were more sensitive to paclitaxel and the MCL1 antagonist S63845. Likewise, PDX models with BAK/MCL1 complexes were more likely to respond to paclitaxel. Mechanistically, BIM induced by low paclitaxel concentrations interacted preferentially with MCL1 and displaced MCL1-bound BAK. Further studies indicated that cells with preformed BAK/MCL1 complexes were sensitive to the paclitaxel/S63845 combination, while cells without BAK/MCL1 complexes were not. Our study suggested that the assessment of BAK/MCL1 complexes might be useful for predicting response to paclitaxel alone or in combination with BH3 mimetics.

The role of SIRT5 and p53 proteins in the sensitivity of colon cancer cells to chemotherapeutic agent 5-Fluorouracil

BACKGROUND

In the treatment of colorectal cancer, it is important to develop drug combinations that will increase the effectiveness of chemotherapy and to determine the molecular targets of the drugs. Therefore, combined therapies that can increase the sensitivity of 5-Fluorouracil (5-FU) and the molecular pathways involved in this process are important in the treatment of the disease. Here we examined the SIRT5 (Resveratrol and Suramin) and p53 (Nutlin3a) modulators alone or in combination with 5-FU on the proliferation of colon cancer cells and effect of 5-FU on the SIRT5 and FOXO3a protein expressions whether p53 dependent or independent manner. METHODS AND RESULTS: According to our MTT assay results, Resveratrol (RSV), Nutlin3a and Suramin was found to be more effective in HCT-116 p53+/+ cells and these differences were evaluated together with the effect of 5-FU on the SIRT5, FOXO3a and Bim protein expressions in HCT-116 p53 +/+ and HCT-116 p53 -/- cells. SIRT5 is known to deacetylate FOXO3a which plays roles in the induction of apoptosis via Bim protein. Our western blot experiment results showed that while Suramin decreased SIRT5 and RSV decreased FOXO3a protein expressions significantly in HCT-116 p53 -/- cells, 5-FU decreased significantly SIRT5 and FOXO3a protein expressions in a p53 independent manner.

CONCLUSIONS

In this study, the effect of 5-FU on SIRT5 and FOXO 3a proteins was determined for the first time in HCT-116 p53 +/+ and HCT-116 p53 -/- cells. These results may help the discovery of new markers in colon cancer treatment.

The Current Treatment Paradigm for Pancreatic Ductal Adenocarcinoma and Barriers to Therapeutic Efficacy

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis, with a median survival time of 10-12 months. Clinically, these poor outcomes are attributed to several factors, including late stage at the time of diagnosis impeding resectability, as well as multi-drug resistance. Despite the high prevalence of drug-resistant phenotypes, nearly all patients are offered chemotherapy leading to modest improvements in postoperative survival. However, chemotherapy is all too often associated with toxicity, and many patients elect for palliative care. In cases of inoperable disease, cytotoxic therapies are less efficacious but still carry the same risk of serious adverse effects, and clinical outcomes remain particularly poor. Here we discuss the current state of pancreatic cancer therapy, both surgical and medical, and emerging factors limiting the efficacy of both. Combined, this review highlights an unmet clinical need to improve our understanding of the mechanisms underlying the poor therapeutic responses seen in patients with PDAC, in hopes of increasing drug efficacy, extending patient survival, and improving quality of life.

Cell Line-Specific Network Models of ER+ Breast Cancer Identify Potential PI3Kα Inhibitor Resistance Mechanisms and Drug Combinations

Durable control of invasive solid tumors necessitates identifying therapeutic resistance mechanisms and effective drug combinations. In this work, we used a network-based mathematical model to identify sensitivity regulators and drug combinations for the PI3Kα inhibitor alpelisib in estrogen receptor positive (ER⁺) PIK3CA-mutant breast cancer. The model-predicted efficacious combination of alpelisib and BH3 mimetics, for example, MCL1 inhibitors, was experimentally validated in ER⁺ breast cancer cell lines. Consistent with the model, FOXO3 downregulation reduced sensitivity to alpelisib, revealing a novel potential resistance mechanism. Cell line-specific sensitivity to combinations of alpelisib and BH3 mimetics depended on which BCL2 family members were highly expressed. On the basis of these results, newly developed cell line-specific network models were able to recapitulate the observed differential response to alpelisib and BH3 mimetics. This approach illustrates how network-based mathematical models can contribute to overcoming the challenge of cancer drug resistance. SIGNIFICANCE: Network-based mathematical models of oncogenic signaling and experimental validation of its predictions can identify resistance mechanisms for targeted therapies, as this study demonstrates for PI3Kα-specific inhibitors in breast cancer.

A Small Molecule with Bridged Carbonyl and Tri-fluoro-aceto-phenone Groups Impedes Microtubule Dynamics and Subsequently Triggers Cancer Cell Apoptosis

We identified a new microtubule targeted small molecule, which showed significant anticancer activity and induced apoptotic death of cancer cells. Precisely the central bridged carbonyl group and trifluoro-acetophenone group of a bis-benzothiazole molecule (BBT) interacts with tubulin close to the curcumin site and perturbs microtubule dynamics as well as causes microtubule depolymerization. We observed a significant enhancement of fluorescence while BBT interacts with the tubulin through bridged carbonyl moiety, a similar phenomenon to colchicine. Further, BBT activates tumor-suppressing bim and p53-puma axes to inhibit cancer survival. It also shows promising results against a tumor spheroid model. BBT is also capable of tumor regression, which shows that this molecule can serve as a potential template for the design of next-generation microtubule targeted anticancer drugs.

Proteasome inhibitor MG132 induces apoptosis in human osteosarcoma U2OS cells

MG132 is a potent, reversible, and cell-permeable 20S proteasome inhibitor and it is derived from a Chinese medicinal plant. The purpose of this study is to investigate the anticancer effects of MG132 against human osteosarcoma U2OS cells. We first performed MTT and colony formation assays to investigate the anti-proliferative effects of MG132. The results demonstrated that MG132 suppressed the proliferation of U2OS cells. Furthermore, we found that treatment with MG132 increased apoptosis and induced DNA damage in U2OS cells. Additionally, zymography, wound healing, and invasion assays showed that MG132 suppressed the enzymatic activity of matrix metalloproteinases, cell migration, and invasion, respectively of U2OS cells. Furthermore, western blotting assay was performed to investigate the apoptotic signaling pathways in MG132-treated U2OS cells. Our results showed that MG132 downregulated the expression of antiapoptotic proteins, including CDK2, CDK4, Bcl-xL, and Bcl-2, whereas it upregulated the expression of proapoptotic proteins, including p21, p27, p53, p-p53 (ser15, ser20, and ser46), cleaved forms of caspase-3, caspase-7, caspase-9, and PARP, and FOXO3 in U2OS cells. These results demonstrated that MG132 activated apoptotic signaling pathways in U2OS cells. Interestingly, MG132 downregulated the phosphorylation of Akt and Erk. Taken together, our results suggest that MG132 has anticancer effects in U2OS cells. Therefore, MG132 may be a potential therapeutic agent for the treatment of osteosarcoma.

Intrinsically Connected: Therapeutically Targeting the Cathepsin Proteases and the Bcl-2 Family of Protein Substrates as Co-regulators of Apoptosis

Taken with the growing importance of cathepsin-mediated substrate proteolysis in tumor biology and progression, the focus and emphasis placed on therapeutic design and development is coming into fruition. Underpinning this approach is the invariable progression from the direction of fully characterizing cathepsin protease members and their substrate targets, towards targeting such an interaction with tangible therapeutics. The two groups of such substrates that have gained much attention over the years are the pro- and anti- apoptotic protein intermediates from the extrinsic and intrinsic signaling arms of the apoptosis pathway. As proteins that are central to determining cellular fate, some of them present themselves as very favorable candidates for therapeutic targeting. However, considering that both anti- and pro- apoptotic signaling intermediates have been reported to be downstream substrates for certain activated cathepsin proteases, therapeutic targeting approaches based on greater selectivity do need to be given greater consideration. Herein, we review the relationships shared by the cathepsin proteases and the Bcl-2 homology domain proteins, in the context of how the topical approach of adopting 'BH3-mimetics' can be explored further in modulating the relationship between the anti- and pro- apoptotic signaling intermediates from the intrinsic apoptosis pathway and their upstream cathepsin protease regulators. Based on this, we highlight important future considerations for improved therapeutic design.

Inhibition of BRAF and ERK1/2 has synergistic effects on thyroid cancer growth in vitro and in vivo

Mutations in the BRAF gene are highly prevalent in thyroid cancer. However, the response rate of thyroid tumors to BRAF-directed therapies has been mixed. Increasingly, combination therapies inhibiting the MAPK pathway at multiple nodes have shown promise. Recently developed ERK1/2 inhibitors are of interest for use in combination therapies as they have the advantage of inhibiting the most downstream node of the MAPK pathway, therefore preventing pathway reactivation. Here, we examined the effect of combined BRAF inhibition (dabrafenib) and ERK1/2 inhibition (SCH772984) on the growth and survival of a panel of BRAF-mutant thyroid cancer cell lines using in vitro and in vivo approaches. We found that resistance due to MAPK pathway reactivation occurs quickly with single-agent BRAF inhibition, but can be prevented with combined BRAF and ERK1/2 inhibition. Combined inhibition also results in synergistic growth inhibition, decreased clonogenic survival, and enhanced induction of apoptosis in a subset of BRAF-mutant thyroid cancer cells. Finally, combined inhibition of BRAF and ERK1/2 results in enhanced inhibition of tumor growth in an anaplastic thyroid cancer in vivo model. These results provide key rationale to pursue combined BRAF and ERK1/2 inhibition as an alternative therapeutic strategy for BRAF-mutant advanced thyroid cancer patients.

FOXO transcription factor family in cancer and metastasis

Forkhead box O (FOXO) transcription factors regulate diverse biological processes, affecting development, metabolism, stem cell maintenance and longevity. They have also been increasingly recognised as tumour suppressors through their ability to regulate genes essential for cell proliferation, cell death, senescence, angiogenesis, cell migration and metastasis. Mechanistically, FOXO proteins serve as key connection points to allow diverse proliferative, nutrient and stress signals to converge and integrate with distinct gene networks to control cell fate, metabolism and cancer development. In consequence, deregulation of FOXO expression and function can promote genetic disorders, metabolic diseases, deregulated ageing and cancer. Metastasis is the process by which cancer cells spread from the primary tumour often via the bloodstream or the lymphatic system and is the major cause of cancer death. The regulation and deregulation of FOXO transcription factors occur predominantly at the post-transcriptional and post-translational levels mediated by regulatory non-coding RNAs, their interactions with other protein partners and co-factors and a combination of post-translational modifications (PTMs), including phosphorylation, acetylation, methylation and ubiquitination. This review discusses the role and regulation of FOXO proteins in tumour initiation and progression, with a particular emphasis on cancer metastasis. An understanding of how signalling networks integrate with the FOXO transcription factors to modulate their developmental, metabolic and tumour-suppressive functions in normal tissues and in cancer will offer a new perspective on tumorigenesis and metastasis, and open up therapeutic opportunities for malignant diseases.

Taxanes in cancer treatment: Activity, chemoresistance and its overcoming

Since 1984, when paclitaxel was approved by the FDA for the treatment of advanced ovarian carcinoma, taxanes have been widely used as microtubule-targeting antitumor agents. However, their historic classification as antimitotics does not describe all their functions. Indeed, taxanes act in a complex manner, altering multiple cellular oncogenic processes including mitosis, angiogenesis, apoptosis, inflammatory response, and ROS production. On the one hand, identification of the diverse effects of taxanes on oncogenic signaling pathways provides opportunities to apply these cytotoxic drugs in a more rational manner. On the other hand, this may facilitate the development of novel treatment modalities to surmount anticancer drug resistance. In the latter respect, chemoresistance remains a major impediment which limits the efficacy of antitumor chemotherapy. Taxanes have shown impact on key molecular mechanisms including disruption of mitotic spindle, mitosis slippage and inhibition of angiogenesis. Furthermore, there is an emerging contribution of cellular processes including autophagy, oxidative stress, epigenetic alterations and microRNAs deregulation to the acquisition of taxane resistance. Hence, these two lines of findings are currently promoting a more rational and efficacious taxane application as well as development of novel molecular strategies to enhance the efficacy of taxane-based cancer treatment while overcoming drug resistance. This review provides a general and comprehensive picture on the use of taxanes in cancer treatment. In particular, we describe the history of application of taxanes in anticancer therapeutics, the synthesis of the different drugs belonging to this class of cytotoxic compounds, their features and the differences between them. We further dissect the molecular mechanisms of action of taxanes and the molecular basis underlying the onset of taxane resistance. We further delineate the possible modalities to overcome chemoresistance to taxanes, such as increasing drug solubility, delivery and pharmacokinetics, overcoming microtubule alterations or mitotic slippage, inhibiting drug efflux pumps or drug metabolism, targeting redox metabolism, immune response, and other cellular functions.

HER2 Signaling in Breast Cancer

HER2 gene amplification occurs in many breast cancer patients and is associated with poor clinical prognosis. Trastuzumab is a therapeutic monoclonal antibody binding to HER2 and inhibits growth of HER2-positive breast cancer cells and used as a principal treatment for HER2-positive breast cancer. Unfortunately, some HER2-positive breast cancers eventually relapse after trastuzumab treatment. To investigate the molecular mechanism of trastuzumab resistance, we generated trastuzumab-resistant cells using a mouse model and found ECM1 protein is increased in trastuzumab-resistant cells. ECM1 was shown to increase EGFR signaling via upregulated matrix metalloproteinase 9/galectin-3/mucin pathway. To further find the novel mediators of HER2-driven signaling pathways in breast cancer, we investigated the upregulated proteins in HER2-overexpressing breast cancer cells using a proteomics approach and found that KRT19 is strongly upregulated in HER2-positive breast cancer cells and it activates HER2 signaling by binding to HER2 and stabilizes the receptor on the cell membrane. Moreover, we found that treatment of KRT19 antibody resulted in reduced cell viability of trastuzumab-resistant HER2-positive breast cancer cells as well as trastuzumab-sensitive cancer cells both in vitro and in vivo.

MicroRNA-302a is involved in folate deficiency-induced apoptosis through the AKT-FOXO1-BIM pathway in mouse embryonic stem cells

Background

Our previous study had shown that microRNA (miR)-302a played a key role in folate deficiency-induced apoptosis in mouse embryonic stem cells. However, details regarding the mechanism remain unclear. Transcription factors (TFs) and miRNAs are two key elements in gene regulation. The aim of this study is to construct the TF-miRNA gene regulation network and demonstrate its possible mechanism.

Methods

The TF-miRNA gene regulation network was constructed via bioinformatics methods. Chromatin immuno-coprecipitation PCR was selected to confirm the binding between miR-302a and TF. mRNA and protein levels were detected by Real-time quantitative PCR and western blotting. TargetScan prediction and Dual-Luciferase Reporter Assay system were used to confirm whether the miRNA binded directly to the predicted target gene.

Results

FOXO1 and miR-302a were selected as the key TF and miRNA, respectively. FOXO1 was confirmed to bind directly to the upstream promoter region of miR-302a. Real-time quantitative PCR and immunoblotting showed that in folate-free conditions, miR-302a and AKT were down regulated, while FOXO1 and Bim were up-regulated significantly. Additionally, treatment with LY294002 inhibitor revealed the involvement of the Akt/FOXO1/Bim signaling pathway in folate deficiency-induced apoptosis, rather than the ERK pathway. Finally, TargetScan prediction and double luciferase reporting experiments illustrated the ability of miR-302a to target the Bim 3′UTR region.

Conclusion

The involvement of miR-302a in folate deficiency-induced apoptosis through the AKT-FOXO1-BIM pathway in mESCs is a unique demonstration of the regulation mechanism of nutrient expression in embryonic development.

FOXO3a-driven miRNA signatures suppresses VEGF-A/NRP1 signaling and breast cancer metastasis

Metastasis remains the major obstacle to improved survival for breast cancer patients. Downregulation of FOXO3a transcription factor in breast cancer is causally associated with the development of metastasis through poorly understood mechanisms. Here, we report that FOXO3a is functionally related to the inhibition of VEGF-A/NRP1 signaling and to the consequent suppression of breast cancer metastasis. We show that FOXO3a directly induces miR-29b-2 and miR-338 expression. Ectopic expression of miR-29b-2/miR-338 significantly suppresses EMT, migration/invasion, and in vivo metastasis of breast cancer. Moreover, we demonstrate that miR-29b-2 directly targets VEGF-A while miR-338 directly targets NRP1, and show that regulation of miR-29b-2 and miR-338 mediates the ability of FOXO3a to suppress VEGF-A/NRP1 signaling and breast cancer metastasis. Clinically, our results show that the FOXO3a-miR-29b-2/miR-338-VEGF-A/NRP1 axis is dysregulated and plays a critical role in disease progression in breast cancer. Collectively, our findings propose that FOXO3a functions as a metastasis suppressor, and define a novel signaling axis of FOXO3a-miRNA-VEGF-A/NRP1 in breast cancer, which might be potential therapeutic targets for breast cancer.

Clinical significance of BIM deletion polymorphism in chemoradiotherapy for non-small cell lung cancer

The standard treatment for locally advanced non‐small cell lung cancer (NSCLC) is chemoradiotherapy (CRT) followed by anti‐programmed cell death‐ligand 1 (anti‐PD‐L1) treatment. BIM deletion polymorphism induces the suppression of apoptosis resulting from epidermal growth factor (EGFR)‐tyrosine kinase inhibitors in EGFR‐mutated NSCLC patients. We aimed to examine the effects of BIM polymorphism on CRT and anti‐PD‐L1/PD‐1 treatment in NSCLC patients. In this retrospective study of 1312 patients with unresectable NSCLC treated at Higashi‐Hiroshima Medical Center and Hiroshima University Hospital between April 1994 and October 2019, we enrolled those who underwent CRT or chemotherapy using carboplatin + paclitaxel or cisplatin + vinorelbine, or anti‐PD‐L1/PD‐1 treatment. Of 1312 patients, 88, 80, and 74 underwent CRT, chemotherapy, and anti‐PD‐L1/PD‐1 treatment, respectively, and 17.0%, 15.2% and 17.6% of these patients showed BIM polymorphism. Among patients receiving CRT, the progression‐free survival was significantly shorter in those with BIM deletion than in those without. In the multivariate analyses, BIM polymorphism was an independent factor of poor anti‐tumor effects. These results were not observed in the chemotherapy and anti‐PD‐L1/PD‐1 treatment groups. In in vitro experiments, BIM expression suppression using small interfering RNA in NSCLC cell lines showed a significantly suppressed anti‐tumor effect and apoptosis after irradiation but not chemotherapy. In conclusion, we showed that BIM polymorphism was a poor‐predictive factor for anti‐tumor effects in NSCLC patients who underwent CRT, specifically radiotherapy. In the implementation of CRT in patients with BIM polymorphism, we should consider subsequent treatment, keeping in mind that CRT may be insufficient.

Transcriptional profiling of embryo cryotolerance

The cryosurvival of embryos is a complex process involving dynamic and integrated morphological, functional, and molecular changes. Here, we evaluated the transcriptional profiling of bovine embryos possessing high and low cryotolerance (HC and LC, respectively) by assessing the resumption of development. Embryos were produced in vitro (N = 1137) and cryopreserved (N = 894). Blastocysts samples possessed pronounced group individualization at RNA sequencing. A total of 114 genes were differentially expressed, and 27 and 84 genes were upregulated in HC and LC, respectively. Among the over-represented biological functions, cellular growth and proliferation, cell death and survival, and organismal survival were predicted to be activated, while cellular movement and cell-to-cell signaling were predicted to be inhibited in HC embryos. Enriched canonical pathways and upstream regulators related to cellular proliferation and survival (HC), inflammatory processes, and cell death (LC) were predicted to represent two embryonic molecular profiles present during the resumption of development after cryopreservation. The marked contrast in transcriptional profiles between HC and LC strongly suggests the influence of embryonic competence after cryopreservation on its respective transcriptome and indicated that HC and LC presented two different molecular strategies to overcome cryopreservation-related stress and resume postcryopreservation development.

Applied electric fields suppress osimertinib-induced cytotoxicity via inhibiting FOXO3a nuclear translocation through AKT activation

Osimertinib is a third-generation epidermal growth factor receptor tyrosine kinase inhibitor against T790M-mutant non-small cell lung cancer (NSCLC). Acquired resistance to osimertinib is a growing clinical challenge that is not fully understood. Endogenous electric fields (EFs), components of the tumor microenvironment, are associated with cancer cell migration and proliferation. However, the impact of EFs on drug efficiency has not been studied. In this study, we observed that EFs counteracted the effects of osimertinib. EFs of 100 mV/mm suppressed osimertinib-induced cell death and promoted cell proliferation. Transcriptional analysis revealed that the expression pattern induced by osimertinib was altered by EFs stimulation. KEGG analysis showed that differential expression genes were mostly enriched in PI3K-AKT pathway. Then, we found that osimertinib inhibited AKT phosphorylation, while EFs stimulation resulted in significant activation of AKT, which could override the effects generated by osimertinib. Importantly, pharmacological inhibition of PI3K/AKT by LY294002 diminished EF-induced activation of AKT and restored the cytotoxicity of osimertinib suppressed by EFs, which proved that AKT activation was essential for EFs to attenuate the efficacy of osimertinib. Furthermore, activation of AKT by EFs led to phosphorylation of forkhead box O3a (FOXO3a), and reduction in nuclear translocation of FOXO3a induced by osimertinib, resulting in decreased expression of Bim and attenuated cytotoxicity of osimertinib. Taken together, we demonstrated that EFs suppressed the antitumor activity of osimertinib through AKT/FOXO3a/Bim pathway, and combination of PI3K/AKT inhibitor with osimertinib counteracted the effects of EFs. Our findings provided preliminary data for therapeutic strategies to enhance osimertinib efficacy in NSCLC patients.

Reciprocal regulation between GCN2 (eIF2AK4) and PERK (eIF2AK3) through the JNK-FOXO3 axis to modulate cancer drug resistance and clonal survival

Pharmaceutical inhibitors of the endoplasmic reticulum (ER)-stress modulator PERK (eIF2AK3) have demonstrated anticancer activities in combination therapies, but their effectiveness as a single agent is limited, suggesting the existence of possible compensatory cellular responses. To explore the potential mechanisms involved, we performed time-course drug treatment experiments on the parental MCF-7 and drug resistant MCF-7Epi^R and MCF-7Tax^R breast cancer cells and identified GCN2 (eIF2AK4) as a molecule that can potentially cooperate with PERK to regulate FOXO3 via JNK and AKT to modulate drug response. Consistently, GCN2 knockdown severely impaired the clonal survival of parental and resistant MCF-7 cells and sensitised them to epirubicin and paclitaxel treatment. Western blot, RT-qPCR and ChIP analyses also confirmed that GCN2 inactivation causes an induction of JNK and thereby FOXO3 activity, culminating in an increase in PERK activity and expression at the transcription level. Conversely, PERK-inactivation using GSK2606414-induces an induction in GCN2 expression and activity also associated with JNK. In agreement, we also showed that the perk^-/- MEFs, expressing elevated levels of P-JNK, JNK, GCN2 and reduced levels of P-AKT and P-FOXO3, have lower clonogenicity and are more sensitive to epirubicin compared to wild-type MEFs. Similarly, gcn2^-/- MEFs expressing augmented levels of P-JNK, JNK, P-PERK, PERK and lower levels of P-AKT and P-FOXO3 also had lower clonogenicity and were more sensitive to epirubicin and PERK-inhibition. In addition, JNK1/2 deletion in MEFs resulted in reduced levels of GCN2, FOXO3, PERK, P-PERK expression as well as FOXO3 activity and enhanced clonal survival and resistance to PERK-inhibition. Together these results demonstrate that GCN2 cooperates with PERK through the JNK-FOXO3 axis in a reciprocal negative feedback loop to mediate cancer chemotherapeutic drug response and clonal survival, advocating the potential of targeting GCN2 as a therapeutic strategy for treating cancer and for overcoming drug resistance.

mRNA Processing: An Emerging Frontier in the Regulation of Pancreatic β Cell Function

Robust endocrine cell function, particularly β cell function, is required to maintain blood glucose homeostasis. Diabetes can result from the loss or dysfunction of β cells. Despite decades of clinical and basic research, the precise regulation of β cell function and pathogenesis in diabetes remains incompletely understood. In this review, we highlight RNA processing of mRNAs as a rapidly emerging mechanism regulating β cell function and survival. RNA-binding proteins (RBPs) and RNA modifications are primed to be the next frontier to explain many of the poorly understood molecular processes that regulate β cell formation and function, and provide an exciting potential for the development of novel therapeutics. Here we outline the current understanding of β cell specific functions of several characterized RBPs, alternative splicing events, and transcriptome wide changes in RNA methylation. We also highlight several RBPs that are dysregulated in both Type 1 and Type 2 diabetes, and discuss remaining knowledge gaps in the field.

Levobupivacaine inhibits proliferation and promotes apoptosis of breast cancer cells by suppressing the PI3K/Akt/mTOR signalling pathway

Objective

This study aimed to test the hypothesis that levobupivacaine has anti-tumour effects on breast cancer cells.

Results

Colony formation and transwell assay were used to determine breast cancer cells proliferation. Flow Cytometry (annexin V and PI staining) was used to investigate breast cancer cells apoptosis. The effects of levobupivacaine on cellular signalling and molecular response were studied with Quantitative Polymerase Chain Reaction and western blot. Induction of apoptosis was confirmed by cell viability, morphological changes showed cell shrinkage, rounding, and detachments from plates. The results of the western blot and Quantitative Polymerase Chain Reaction indicated activation of active caspase-3 and inhibition of FOXO1. The results of the flow Cytometry confirmed that levobupivacaine inhibited breast cancer cell proliferation and enhanced apoptosis of breast cancer cells. Quantitative Polymerase Chain Reaction and Western blot analysis showed increased p21 and decreased cyclin D. Quantitative Polymerase Chain Reaction and western blot analysis showed that levobupivacaine significantly increased Bax expression, accompanied by a significant decreased Bcl-2 expression and inhibition of PI3K/Akt/mTOR signalling pathway. These findings suggested that levobupivacaine inhibits proliferation and promotes breast cancer cells apoptosis in vitro.

Induction of cell cycle arrest and apoptosis by tomentosin in hepatocellular carcinoma HepG2 and Huh7 cells

Tomentosin, a sesquiterpene lactone, is known to possess various biological activities. However, its anticarcinogenic activity against human hepatocellular carcinoma (HCC) cells has not been investigated in detail. Thus, this study aimed to elucidate the cytotoxic mechanism of tomentosin in human HCC cell lines HepG2 and Huh7. WST-1, cell counting, and colony formation assay results showed that treatment with tomentosin decreased the viability and suppressed the proliferation rate of HepG2 and Huh7 cells in a dose- and time-dependent manner. Cell cycle analysis revealed increased population of cells at the SubG1 and G2/M stage, and decreased population of cells at the G0/1 stage in HepG2 and Huh7 cells treated with tomentosin. Annexin V/propidium iodide double staining and TUNEL assay results showed increased apoptotic cell population and DNA fragmentation in HepG2 and Huh7 cells treated with tomentosin. Western blotting analysis results showed that tomentosin treatment significantly increased the expression level of Bax, Bim (short form), cleaved PARP1, FOXO3, p53, pSer15p53, pSer20p53, pSer46p53, p21, and p27, but decreased the expression of Bcl2, caspase3, caspase7, caspase9, cyclin-dependent kinase 2 (CDK2), CDK4, CDK6, cyclinB1, cyclinD1, cyclinD2, cyclinD3, and cyclinE in a dose-dependent manner. Taken together, this study revealed that tomentosin, which acted through cell cycle arrest and apoptosis, may be a useful therapeutic option against HCC.

EGFR/FOXO3a/BIM signaling pathway determines chemosensitivity of BMP4-differentiated glioma stem cells to temozolomide

Accumulating evidence suggests that glioma stem cells (GSCs), which are rare cells characterized by pluripotency and self-renewal ability, are responsible for glioblastoma (GBM) propagation, recurrence and resistance to therapies. Bone morphogenic proteins (BMPs) induce GSC differentiation, which leads to elimination of GSCs and sensitization of glioma to chemotherapeutics. Alterations in the epidermal growth factor receptor (EGFR) gene are detected in more than half of GBMs; however, the role of EGFR in the chemoresistance of GSCs remains unknown. Here, we examined whether EGFR signaling affects BMP4-induced differentiation of GSCs and their response to the alkylating drug temozolomide (TMZ). We show that BMP4 triggers the SMAD signaling cascade in GSCs independent of the EGFR level. BMP4 downregulated the levels of pluripotency markers (SOX2 and OLIG2) with a concomitant induction of an astrocytic marker (GFAP) and a neuronal marker (β-Tubulin III). However, GSCs with different EGFR levels responded differently to treatments. BMP4-induced differentiation did not enhance sensitivity to TMZ in EGFR^low GSCs, in contrast to EGFR^high GSCs, which underwent apoptosis. We then identified differences in cell cycle regulation. In EGFR^low cells, BMP4-triggered G1 cell cycle arrest which was not detected in EGFR^high cells. RNA-seq profiles further highlighted transcriptomic alterations and distinct processes characterizing EGFR-dependent responses in the course of BMP4-induced differentiation. We found that the control of BIM (the pro-apoptotic BCL-2 family protein) by the AKT/FOXO3a axis only operated in BMP4-differentiated EGFR^high cells upon TMZ treatment.

The properties of individual glioma stem cells (GSCs) may influence the success of chemotherapy in tackling aggressive brain cancer. GSCs promote tumor growth and chemotherapy resistance in glioblastoma tumors. One potential treatment approach uses bone morphogenetic proteins to induce GSCs to differentiate into less harmful cells. Once the GSC population has dwindled, chemoresistance reduces in many but not all cases. Jakub Mieczkowski, Bozena Kaminska and co-workers at the Nencki Institute of Experimental Biology in Warsaw, Poland, conducted experiments on patient-derived glioblastoma cell cultures. They found that samples with high expression levels of the epidermal growth factor receptor (EGFR) protein in GSCs showed heightened sensitivity to the chemotherapy drug temozolomide after differentiation. Conversely, low levels of EGFR resulted in chemoresistance being maintained after differentiation, which may explain the failure of chemotherapy in some patients.

Inhibition of MEK1/2 Forestalls the Onset of Acquired Resistance to Entrectinib in Multiple Models of NTRK1-Driven Cancer

NTRK1 gene fusions are actionable drivers of numerous human malignancies. Here, we show that expression of the TPR-NTRK1 fusion kinase in immortalized mouse pancreatic ductal epithelial (IMPE) (pancreas) or mouse lung epithelial (MLE-12) cells is sufficient to promote rapidly growing tumors in mice. Both tumor models are exquisitely sensitive to targeted inhibition with entrectinib, a tropomyosin-related kinase A (TRKA) inhibitor. Initial regression of NTRK1-driven tumors is driven by induced expression of BIM, such that BIM silencing leads to a diminished response to entrectinib in vivo. However, the emergence of drug-resistant disease limits the long-term durability of responses. Based on the reactivation of RAF>MEK>ERK signaling observed in entrectinib-treated tumors, we show that the combination of entrectinib plus the MEK1/2 inhibitor cobimetinib dramatically forestalls the onset of drug resistance in vivo. Collectively, these data provide a mechanistic rationale for rapid clinical deployment of combined inhibition of TRKA plus MEK1/2 in NTRK1-driven cancers.

Marine compounds targeting the PI3K/Akt signaling pathway in cancer therapy

Cancer is a disease characterized by overproliferation, including that due to transformation, apoptosis disorders, proliferation, invasion, angiogenesis and metastasis, and is one of the deadliest diseases. Currently, conservative chemotherapy is used for cancer treatment due to a lack of effective drugs. The PI3K/Akt signaling pathway plays a very essential role in the pathogenesis of many cancers, and abnormal activation of this pathway leads to abnormal expression of a series of downstream proteins, which ultimately results in the excessive proliferation of cancer cells. Therefore, the PI3K/Akt signaling pathway is a critical target in cancer treatment. Marine drugs have attracted much attention in recent years, and studies have found that many extracts from oceanic animals, plants and microorganisms or their metabolites exert antitumor effects, including antiproliferative effects or the induction of cell cycle arrest, apoptosis or autophagy. However, most anticancer targets and the mechanisms of marine compounds remain unclear. The great potential of the development of marine drugs provides a new direction for cancer treatment. This review focuses on marine compounds that target the PI3K/Akt signaling pathway for the prevention and treatment of cancer and provides comprehensive information for those interested in research on marine drugs.

PRKCQ inhibition enhances chemosensitivity of triple-negative breast cancer by regulating Bim

BACKGROUND

Protein kinase C theta, (PRKCQ/PKCθ) is a serine/threonine kinase that is highly expressed in a subset of triple-negative breast cancers (TNBC) and promotes their growth, anoikis resistance, epithelial-mesenchymal transition (EMT), and invasion. Here, we show that PRKCQ regulates the sensitivity of TNBC cells to apoptosis triggered by standard-of-care chemotherapy by regulating levels of pro-apoptotic Bim.

METHODS

To determine the effects of PRKCQ expression on chemotherapy-induced apoptosis, shRNA and cDNA vectors were used to modulate the PRKCQ expression in MCF-10A breast epithelial cells or triple-negative breast cancer cells (MDA-MB231Luc, HCC1806). A novel PRKCQ small-molecule inhibitor, 17k, was used to inhibit kinase activity. Viability and apoptosis of cells treated with PRKCQ cDNA/shRNA/inhibitor +/-chemotherapy were measured. Expression levels of Bcl2 family members were assessed.

RESULTS

Enhanced expression of PRKCQ is sufficient to suppress apoptosis triggered by paclitaxel or doxorubicin treatment. Downregulation of PRKCQ also enhanced the apoptosis of chemotherapy-treated TNBC cells. Regulation of chemotherapy sensitivity by PRKCQ mechanistically occurs via regulation of levels of Bim, a pro-apoptotic Bcl2 family member; suppression of Bim prevents the enhanced apoptosis observed with combined PRKCQ downregulation and chemotherapy treatment. Regulation of Bim and chemotherapy sensitivity is significantly dependent on PRKCQ kinase activity; overexpression of a catalytically inactive PRKCQ does not suppress Bim or chemotherapy-associated apoptosis. Furthermore, PRKCQ kinase inhibitor treatment suppressed growth, increased anoikis and Bim expression, and enhanced apoptosis of chemotherapy-treated TNBC cells, phenocopying the effects of PRKCQ downregulation.

CONCLUSIONS

These studies support PRKCQ inhibition as an attractive therapeutic strategy and complement to chemotherapy to inhibit the growth and survival of TNBC cells.