eIF-4E expression and its role in malignancies and metastases

eIF4E orchestrates mRNA processing, RNA export and translation to modify specific protein production

The eukaryotic translation initiation factor eIF4E acts as a multifunctional factor that simultaneously influences mRNA processing, export, and translation in many organisms. Its multifactorial effects are derived from its capacity to bind to the methyl-7-guanosine cap on the 5'end of mRNAs and thus can act as a cap chaperone for transcripts in the nucleus and cytoplasm. In this review, we describe the multifactorial roles of eIF4E in major mRNA-processing events including capping, splicing, cleavage and polyadenylation, nuclear export and translation. We discuss the evidence that eIF4E acts at two levels to generate widescale changes to processing, export and ultimately the protein produced. First, eIF4E alters the production of components of the mRNA processing machinery, supporting a widescale reprogramming of multiple mRNA processing events. In this way, eIF4E can modulate mRNA processing without physically interacting with target transcripts. Second, eIF4E also physically interacts with both capped mRNAs and components of the RNA processing or translation machineries. Further, specific mRNAs are sensitive to eIF4E only in particular mRNA processing events. This selectivity is governed by the presence of cis-acting elements within mRNAs known as USER codes that recruit relevant co-factors engaging the appropriate machinery. In all, we describe the molecular bases for eIF4E's multifactorial function and relevant regulatory pathways, discuss the basis for selectivity, present a compendium of ~80 eIF4E-interacting factors which play roles in these activities and provide an overview of the relevance of its functions to its oncogenic potential. Finally, we summarize early-stage clinical studies targeting eIF4E in cancer.

Development of an Imidazopyridazine-Based MNK1/2 Inhibitor for the Treatment of Lymphoma

The mitogen-activated protein kinase-interacting protein kinases (MNKs) are the only kinases known to phosphorylate eukaryotic translation initiation factor 4E (eIF4E) at Ser209, which plays a significant role in cap-dependent translation. Dysregulation of the MNK/eIF4E axis has been found in various solid tumors and hematological malignancies, including diffuse large B-cell lymphoma (DLBCL). Herein, structure-activity relationship studies and docking models determined that 20j exhibits excellent MNK1/2 inhibitory activity, stability, and hERG safety. 20j exhibits strong and broad antiproliferative activity against different cancer cell lines, especially GCB-DLBCL DOHH2. 20j suppresses the phosphorylation of eIF4E in Hela cells (IC50 = 90.5 nM) and downregulates the phosphorylation of eIF4E and 4E-BP1 in A549 cells. In vivo studies first revealed that ibrutinib enhances the antitumor effect of 20j without side effects in a DOHH2 xenograft model. This study provided a solid foundation for the future development of a MNK inhibitor for GCB-DLBCL treatment.

Eukaryotic Initiation Factor 4E (eIF4E) as a Target of Anti-Psoriatic Treatment

Eukaryotic initiation factor 4E (eIF4E) has been known to play a critical role in the regulation of gene expression and essential cellular processes, such as proliferation, apoptosis and differentiation. In this study, we explored its role in the pathophysiology of psoriasis. The inhibition of eIF4E by small interfering RNA or briciclib, an eIF4E small molecule inhibitor, downregulated the expression of eIF4E itself and its two complex partners eIF4A and G, as well as other eIFs (eg, eIF1A, eIF2α, eIF3A, eIF3B, eIF5, and eIF6). This inhibition also abolished psoriatic inflammation in both the imiquimod and TGFß mouse model, as well as in a human 3 dimensional-psoriasis tissue model. Downregulation of eIF4E and the other eIFs by application of briciclib (particularly when given topically) was linked to the normalization of cellular proliferation, epidermal hyperplasia, levels of proinflammatory cytokines (eg, TNFα, IL-1b, IL-17, and IL-22), and keratinocyte differentiation markers (eg, KRT16 and FLG). These results demonstrate translational imbalance and underline the crucial role played by eIF4E and other eIFs in the pathophysiology of psoriasis. This work opens up avenues for the development of novel topical antipsoriatic treatment strategies by targeting eIF4E.

HPV+ head and neck cancer-derived small extracellular vesicles communicate with TRPV1+ neurons to mediate cancer pain

ABSTRACT

Severe pain is often experienced by patients with head and neck cancer and is associated with a poor prognosis. Despite its frequency and severity, current treatments fail to adequately control cancer-associated pain because of our lack of mechanistic understanding. Although recent works have shed some light of the biology underlying pain in HPV-negative oral cancers, the mechanisms mediating pain in HPV+ cancers remain unknown. Cancer-derived small extracellular vesicles (cancer-sEVs) are well positioned to function as mediators of communication between cancer cells and neurons. Inhibition of cancer-sEV release attenuated pain in tumor-bearing mice. Injection of purified cancer-sEVs is sufficient to induce pain hypersensitivity in naive mice that is prevented by QX-314 treatment and in Trpv1-/- mice. Cancer-sEVs triggered calcium influx in nociceptors, and inhibition or ablation of nociceptors protects against cancer pain. Interrogation of published sequencing data of human sensory neurons exposed to human cancer-sEVs suggested a stimulation of protein translation in neurons. Induction of translation by cancer-sEVs was validated in our mouse model, and its inhibition alleviated cancer pain in mice. In summary, our work reveals that HPV+ head and neck squamous cell carcinoma-derived sEVs alter TRPV1+ neurons by promoting nascent translation to mediate cancer pain and identified several promising therapeutic targets to interfere with this pathway.

Altered hormone expression induced genetic changes leads to breast cancer

PURPOSE OF REVIEW

Breast cancer ranks first among gynecological cancer in India. It is associated with urbanization, changes in lifestyle and obesity. Hormones also play a crucial role in the development of breast cancer. Steroid hormones play critical role in development of breast cancer.

RECENT FINDING

Breast cancer is caused due to alteration in different hormone expressions leading to genetic instability. Loss or gains of functions due to genetic instability were associated with the alterations in housekeeping genes. Up-regulation in c-myc, signal transducer and activator of transcription (STAT), CREB-regulated transcription coactivator (CRTC), and eukaryotic translation initiation factor 4E (eIF4E) may cause the development of breast cancer. Peptide hormones are commonly following the phosphoinositide 3-kinases (PI3K) pathway for activation of cell cycle causing uncontrolled proliferation. Although steroid hormones are following the Ras/Raf/mitogen-activated protein kinase (MEK) pathway, their hyper-activation of these pathways causes extracellular-signal-regulated kinase (ERK) and MAPK activation, leading to carcinogenesis.

SUMMARY

Alteration in cell cycle proteins, oncogenes, tumor suppressor genes, transcription and translation factors lead to breast cancer. Apoptosis plays a vital role in the elimination of abnormal cells but failure in any of these apoptotic pathways may cause tumorigenesis. Hence, a complex interplay of hormonal and genetic factors is required to maintain homeostasis in breast cells. Imbalance in homeostasis of these hormone and genes may lead to breast cancer.

Integrative modeling uncovers p21-driven drug resistance and prioritizes therapies for PIK3CA-mutant breast cancer

Utility of PI3Kα inhibitors like BYL719 is limited by the acquisition of genetic and non-genetic mechanisms of resistance which cause disease recurrence. Several combination therapies based on PI3K inhibition have been proposed, but a way to systematically prioritize them for breast cancer treatment is still missing. By integrating published and in-house studies, we have developed in silico models that quantitatively capture dynamics of PI3K signaling at the network-level under a BYL719-sensitive versus BYL719 resistant-cell state. Computational predictions show that signal rewiring to alternative components of the PI3K pathway promote resistance to BYL719 and identify PDK1 as the most effective co-target with PI3Kα rescuing sensitivity of resistant cells to BYL719. To explore whether PI3K pathway-independent mechanisms further contribute to BYL719 resistance, we performed phosphoproteomics and found that selection of high levels of the cell cycle regulator p21 unexpectedly promoted drug resistance in T47D cells. Functionally, high p21 levels favored repair of BYL719-induced DNA damage and bypass of the associated cellular senescence. Importantly, targeted inhibition of the check-point inhibitor CHK1 with MK-8776 effectively caused death of p21-high T47D cells, thus establishing a new vulnerability of BYL719-resistant breast cancer cells. Together, our integrated studies uncover hidden molecular mediators causing resistance to PI3Kα inhibition and provide a framework to prioritize combination therapies for PI3K-mutant breast cancer.

Small molecule inhibition of RNA binding proteins in haematologic cancer

In recent years, advances in biomedicine have revealed an important role for post-transcriptional mechanisms of gene expression regulation in pathologic conditions. In cancer in general and leukaemia specifically, RNA binding proteins have emerged as important regulator of RNA homoeostasis that are often dysregulated in the disease state. Having established the importance of these pathogenetic mechanisms, there have been a number of efforts to target RNA binding proteins using oligonucleotide-based strategies, as well as with small organic molecules. The field is at an exciting inflection point with the convergence of biomedical knowledge, small molecule screening strategies and improved chemical methods for synthesis and construction of sophisticated small molecules. Here, we review the mechanisms of post-transcriptional gene regulation, specifically in leukaemia, current small-molecule based efforts to target RNA binding proteins, and future prospects.

C8ORF88: A Novel eIF4E-Binding Protein

Translation initiation in eukaryotes is regulated at several steps, one of which involves the availability of the cap binding protein to participate in cap-dependent protein synthesis. Binding of eIF4E to translational repressors (eIF4E-binding proteins [4E-BPs]) suppresses translation and is used by cells to link extra- and intracellular cues to protein synthetic rates. The best studied of these interactions involves repression of translation by 4E-BP1 upon inhibition of the PI3K/mTOR signaling pathway. Herein, we characterize a novel 4E-BP, C8ORF88, whose expression is predominantly restricted to early spermatids. C8ORF88:eIF4E interaction is dependent on the canonical eIF4E binding motif (4E-BM) present in other 4E-BPs. Whereas 4E-BP1:eIF4E interaction is dependent on the phosphorylation of 4E-BP1, these sites are not conserved in C8ORF88 indicating a different mode of regulation.

Post-transcriptional regulation of myeloid cell-mediated inflammatory responses

Myeloid cells, particularly macrophages, act as the frontline responders to infectious agents and initiate inflammation. While the molecular mechanisms driving inflammatory responses have primarily focused on pattern recognition by myeloid cells and subsequent transcriptional events, it is crucial to note that post-transcriptional regulation plays a pivotal role in this process. In addition to the transcriptional regulation of innate immune responses, additional layers of intricate network of post-transcriptional mechanisms critically determine the quantity and duration of key inflammatory products and thus the outcome of immune responses. A multitude of mechanisms governing post-transcriptional regulation in innate immunity have been uncovered, encompassing RNA alternative splicing, mRNA stability, and translational regulation. This review encapsulates the current insights into the post-transcriptional regulation of inflammatory genes within myeloid cells, with particular emphasis on translational regulation during inflammation. While acknowledging the advancements, we also shed light on the existing gaps in immunological research pertaining to post-transcriptional levels and propose perspectives that controlling post-transcriptional process may serve as potential targets for therapeutic interventions in inflammatory diseases.

Biological functions and research progress of eIF4E

The eukaryotic translation initiation factor eIF4E can specifically bind to the cap structure of an mRNA 5' end, mainly regulating translation initiation and preferentially enhancing the translation of carcinogenesis related mRNAs. The expression of eIF4E is closely related to a variety of malignant tumors. In tumor cells, eIF4E activity is abnormally increased, which stimulates cell growth, metastasis and translation of related proteins. The main factors affecting eIF4E activity include intranuclear regulation, phosphorylation of 4EBPs, and phosphorylation and sumoylation of eIF4E. In this review, we summarize the biological functions and the research progress of eIF4E, the main influencing factors of eIF4E activity, and the recent progress of drugs targeting eIF4E, in the hope of providing new insights for the treatment of multiple malignancies and development of targeted drugs.

Mechanism underlying follicular hyperproliferation and oncogenesis in hidradenitis suppurativa

Hidradenitis suppurativa (HS) is a skin disorder that causes chronic painful inflammation and hyperproliferation, often with the comorbidity of invasive keratoacanthoma (KA). Our research, employing high-resolution immunofluorescence and data science approaches together with confirmatory molecular analysis, has identified that the 5'-cap-dependent protein translation regulatory complex eIF4F is a key factor in the development of HS and is responsible for regulating follicular hyperproliferation. Specifically, eIF4F translational targets, Cyclin D1 and c-MYC, orchestrate the development of HS-associated KA. Although eIF4F and p-eIF4E are contiguous throughout HS lesions, Cyclin D1 and c-MYC have unique spatial localization and functions. The keratin-filled crater of KA is formed by nuclear c-MYC-induced differentiation of epithelial cells, whereas the co-localization of c-MYC and Cyclin D1 provides oncogenic transformation by activating RAS, PI3K, and ERK pathways. In sum, we have revealed a novel mechanism underlying HS pathogenesis of follicular hyperproliferation and the development of HS-associated invasive KA.

Identification of a First-in-Class Small-Molecule Inhibitor of the EIF4E-RBM38 Complex That Enhances Wild-type TP53 Protein Translation for Tumor Growth Suppression

EIF4E, an mRNA cap-binding protein, is necessary for cap-dependent translation. Overexpression of EIF4E is known to promote cancer development by preferentially translating a group of oncogenic mRNAs. Thus, 4EGI-1, a disruptor of EIF4E-EIF4G1 interaction, was developed to inhibit oncoprotein expression for cancer therapy. Interestingly, RBM38, an RNA-binding protein, interacts with EIF4E on TP53 mRNA, prevents EIF4E from binding to TP53 mRNA cap, and inhibits TP53 expression. Thus, Pep8, an eight amino acid peptide derived from RBM38, was developed to disrupt the EIF4E-RBM38 complex, leading to increased TP53 expression and decreased tumor cell growth. Herein, we have developed a first-in-class small-molecule compound 094, which interacts with EIF4E via the same pocket as does Pep8, dissociates RBM38 from EIF4E, and enhances TP53 translation in RBM38- and EIF4E-dependent manners. Structure-activity relationship studies identified that both the fluorobenzene and ethyl benzamide are necessary for compound 094 to interact with EIF4E. Furthermore, we showed that compound 094 is capable of suppressing three-dimensional tumor spheroid growth in RBM38- and TP53-dependent manners. In addition, we found that compound 094 cooperates with the chemotherapeutic agent doxorubicin and EIF4E inhibitor 4EGI-1 to suppress tumor cell growth. Collectively, we showed that two distinct approaches can be used together to target EIF4E for cancer therapy by enhancing wild-type TP53 expression (094) and by suppressing oncoprotein expression (4EGI-1).

The dark side of mRNA translation and the translation machinery in glioblastoma

Among the different types of cancer affecting the central nervous system (CNS), glioblastoma (GB) is classified by the World Health Organization (WHO) as the most common and aggressive CNS cancer in adults. GB incidence is more frequent among persons aged 45–55 years old. GB treatments are based on tumor resection, radiation, and chemotherapies. The current development of novel molecular biomarkers (MB) has led to a more accurate prediction of GB progression. Moreover, clinical, epidemiological, and experimental studies have established genetic variants consistently associated with the risk of suffering GB. However, despite the advances in these fields, the survival expectancy of GB patients is still shorter than 2 years. Thus, fundamental processes inducing tumor onset and progression remain to be elucidated. In recent years, mRNA translation has been in the spotlight, as its dysregulation is emerging as a key cause of GB. In particular, the initiation phase of translation is most involved in this process. Among the crucial events, the machinery performing this phase undergoes a reconfiguration under the hypoxic conditions in the tumor microenvironment. In addition, ribosomal proteins (RPs) have been reported to play translation-independent roles in GB development. This review focuses on the research elucidating the tight relationship between translation initiation, the translation machinery, and GB. We also summarize the state-of-the-art drugs targeting the translation machinery to improve patients’ survival. Overall, the recent advances in this field are shedding new light on the dark side of translation in GB.

Therapeutic targeting of eukaryotic initiation factor (eIF) 4E

Fundamental studies unraveled the role of eukaryotic initiation factor (eIF) 4E in mRNA translation and its control. Under physiological conditions, regulation of translation by eIF4E is essential to cellular homeostasis. Under stress, gene flow information is parsed by eIF4E to support adaptive mechanisms that favor cell survival. Dysregulated eIF4E activity fuels tumor formation and progression and modulates response to therapy. Thus, there has been heightened interest in understanding eIF4E function in controlling gene expression as well as developing strategies to block its activity to treat disease.

Application of Phosphoramidate ProTide Technology for the Synthesis of 5'-mRNA Cap Analogs Modified on the Exocyclic Amine Group

Aryloxy triester phosphoramidate methodology, commonly known as ProTide technology, is one of the most widely used prodrug approaches applied to therapeutic nucleosides. This approach has been used extensively by the pharmaceutical industry and researchers in medicinal chemistry. Herein we report our adaptation of this effective method for the synthesis of bioactive 5'-mRNA cap analogues as inhibitors for targeting cap-dependent translation. The synthesis was performed in two main stages: preparation of N2-modified guanosine analogues and their subsequent transformation into prodrugs using phenylethoxy-l-alaninyl phosphorochloridate. The prepared pro-nucleotide cap analogues were tested for their capacity in enzymatic activation, inhibitory properties in a rabbit reticulocyte lysate system, and passive membrane translocation properties.

Preclinical Efficacy of a PARP-1 Targeted Auger-Emitting Radionuclide in Prostate Cancer

There is an unmet need for better therapeutic strategies for advanced prostate cancer. Poly (ADP-ribose) polymerase-1 (PARP-1) is a chromatin-binding DNA repair enzyme overexpressed in prostate cancer. This study evaluates whether PARP-1, on account of its proximity to the cell's DNA, would be a good target for delivering high-linear energy transfer Auger radiation to induce lethal DNA damage in prostate cancer cells. We analyzed the correlation between PARP-1 expression and Gleason score in a prostate cancer tissue microarray. A radio-brominated Auger emitting inhibitor ([77Br]Br-WC-DZ) targeting PARP-1 was synthesized. The ability of [77Br]Br-WC-DZ to induce cytotoxicity and DNA damage was assessed in vitro. The antitumor efficacy of [77Br]Br-WC-DZ was investigated in prostate cancer xenograft models. PARP-1 expression was found to be positively correlated with the Gleason score, thus making it an attractive target for Auger therapy in advanced diseases. The Auger emitter, [77Br]Br-WC-DZ, induced DNA damage, G2-M cell cycle phase arrest, and cytotoxicity in PC-3 and IGR-CaP1 prostate cancer cells. A single dose of [77Br]Br-WC-DZ inhibited the growth of prostate cancer xenografts and improved the survival of tumor-bearing mice. Our studies establish the fact that PARP-1 targeting Auger emitters could have therapeutic implications in advanced prostate cancer and provides a strong rationale for future clinical investigation.

Critical Roles of METTL3 in Translation Regulation of Cancer

Aberrant translation, a characteristic feature of cancer, is regulated by the complex and sophisticated RNA binding proteins (RBPs) in the canonical translation machinery. N6-methyladenosine (m⁶A) modifications are the most abundant internal modifications in mRNAs mediated by methyltransferase-like 3 (METTL3). METTL3 is commonly aberrantly expressed in different tumors and affects the mRNA translation of many oncogenes or dysregulated tumor suppressor genes in a variety of ways. In this review, we discuss the critical roles of METTL3 in translation regulation and how METTL3 and m⁶A reader proteins in collaboration with RBPs within the canonical translation machinery promote aberrant translation in tumorigenesis, providing an overview of recent efforts aiming to 'translate' these results to the clinic.

Identification of tumor antigens and immune landscapes for bladder urothelial carcinoma mRNA vaccine

Background

Bladder urothelial carcinoma (BLCA) is associated with high mortality and recurrence. Although mRNA-based vaccines are promising treatment strategies for combating multiple solid cancers, their efficacy against BLCA remains unclear. We aimed to identify potential effective antigens of BLCA for the development of mRNA-based vaccines and screen for immune clusters to select appropriate candidates for vaccination.

Methods

Gene expression microarray data and clinical information were retrieved from The Cancer Genome Atlas and GSE32894, respectively. The mRNA splicing patterns were obtained from the SpliceSeq portal. The cBioPortal for Cancer Genomics was used to visualize genetic alteration profiles. Furthermore, nonsense-mediated mRNA decay (NMD) analysis, correlation analysis, consensus clustering analysis, immune cell infiltration analysis, and weighted co-expression network analysis were conducted.

Results

Six upregulated and mutated tumor antigens related to NMD, and infiltration of APCs were identified in patients with BLCA, including HP1BP3, OSBPL9, SSH3, ZCCHC8, FANCI, and EIF4A2. The patients were subdivided into two immune clusters (IC1 and IC2) with distinct clinical, cellular and molecular features. Patients in IC1 represented immunologically 'hot' phenotypes, whereas those in IC2 represented immunologically 'cold' phenotypes. Moreover, the survival rate was better in IC2 than in IC1, and the immune landscape of BLCA indicated significant inter-patient heterogeneity. Finally, CALD1, TGFB3, and ANXA6 were identified as key genes of BLCA through WGCNA analysis, and their mRNA expression levels were measured using qRT-PCR.

Conclusion

HP1BP3, OSBPL9, SSH3, ZCCHC8, FANCI, and EIF4A2 were identified as potential antigens for developing mRNA-based vaccines against BLCA, and patients in IC2 might benefit more from vaccination.

PM2.5 promotes NSCLC carcinogenesis through translationally and transcriptionally activating DLAT-mediated glycolysis reprograming

Background

Airborne fine particulate matter (PM2.5) has been associated with lung cancer development and progression in never smokers. However, the molecular mechanisms underlying PM2.5-induced lung cancer remain largely unknown. The aim of this study was to explore the mechanisms by which PM2.5 regulated the carcinogenesis of non-small cell lung cancer (NSCLC).

Methods

Paralleled ribosome sequencing (Ribo-seq) and RNA sequencing (RNA-seq) were performed to identify PM2.5-associated genes for further study. Quantitative real time-PCR (qRT-PCR), Western blot, and immunohistochemistry (IHC) were used to determine mRNA and protein expression levels in tissues and cells. The biological roles of PM2.5 and PM2.5-dysregulated gene were assessed by gain- and loss-of-function experiments, biochemical analyses, and Seahorse XF glycolysis stress assays. Human tissue microarray analysis and ¹⁸F-FDG PET/CT scans in patients with NSCLC were used to verify the experimental findings. Polysome fractionation experiments, chromatin immunoprecipitation (ChIP), and dual-luciferase reporter assay were implemented to explore the molecular mechanisms.

Results

We found that PM2.5 induced a translation shift towards glycolysis pathway genes and increased glycolysis metabolism, as evidenced by increased L-lactate and pyruvate concentrations or higher extracellular acidification rate (ECAR) in vitro and in vivo. Particularly, PM2.5 enhanced the expression of glycolytic gene DLAT, which promoted glycolysis but suppressed acetyl-CoA production and enhanced the malignancy of NSCLC cells. Clinically, high expression of DLAT was positively associated with tumor size, poorer prognosis, and SUVmax values of ¹⁸F-FDG-PET/CT scans in patients with NSCLC. Mechanistically, PM2.5 activated eIF4E, consequently up-regulating the expression level of DLAT in polysomes. PM2.5 also stimulated transcription factor Sp1, which further augmented transcription activity of DLAT promoter.

Conclusions

This study demonstrated that PM2.5-activated overexpression of DLAT and enhancement in glycolysis metabolism contributed to the tumorigenesis of NSCLC, suggesting that DLAT-associated pathway may be a therapeutic target for NSCLC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-022-02437-8.

RNA-binding proteins and translation control in angiogenesis

Tissue vascularization through the process of angiogenesis ensures adequate oxygen and nutrient supply during development and regeneration. The complex morphogenetic events involved in new blood vessel formation are orchestrated by a tightly regulated crosstalk between extra and intracellular factors. In this context, RNA-binding protein (RBP) activity and protein translation play fundamental roles during the cellular responses triggered by particular environmental cues. A solid body of work has demonstrated that key RBPs (such as HuR, TIS11 proteins, hnRNPs, NF90, QKIs and YB1) are implicated in both physiological and pathological angiogenesis. These RBPs are critical for the metabolism of messenger (m)RNAs encoding angiogenic modulators and, importantly, strong evidence suggests that RBP-mRNA interactions can be altered in disease. Lesser known, but not less important, the mechanistic aspects of protein synthesis can also regulate the generation of new vessels. In this review, we outline the key findings demonstrating the implications of RBP-mediated RNA regulation and translation control in angiogenesis. Furthermore, we highlight how these mechanisms of post-transcriptional control of gene expression have led to promising therapeutic strategies aimed at targeting undesired blood vessel formation.

Aberrant protein synthesis and cancer development: The role of canonical eukaryotic initiation, elongation and termination factors in tumorigenesis

In tumourigenesis, oncogenes or dysregulated tumour suppressor genes alter the canonical translation machinery leading to a reprogramming of the translatome that, in turn, promotes the translation of selected mRNAs encoding proteins involved in proliferation and metastasis. It is therefore unsurprising that abnormal expression levels and activities of eukaryotic initiation factors (eIFs), elongation factors (eEFs) or termination factors (eRFs) are associated with poor outcome for patients with a wide range of cancers. In this review we discuss how RNA binding proteins (RBPs) within the canonical translation factor machinery are dysregulated in cancers and how targeting such proteins is leading to new therapeutic avenues.

RNA binding proteins in MLL-rearranged leukemia

RNA binding proteins (RBPs) have recently emerged as important post-transcriptional gene expression regulators in both normal development and disease. RBPs influence the fate of mRNAs through multiple mechanisms of action such as RNA modifications, alternative splicing, and miR-mediated regulation. This complex and, often, combinatorial regulation by RBPs critically impacts the expression of oncogenic transcripts and, thus, the activation of pathways that drive oncogenesis. Here, we focus on the major features of RBPs, their mechanisms of action, and discuss the current progress in investigating the function of important RBPs in MLL-rearranged leukemia.

Engineering an autonomous VH domain to modulate intracellular pathways and to interrogate the eIF4F complex

An attractive approach to target intracellular macromolecular interfaces and to model putative drug interactions is to design small high-affinity proteins. Variable domains of the immunoglobulin heavy chain (VH domains) are ideal miniproteins, but their development has been restricted by poor intracellular stability and expression. Here we show that an autonomous and disufhide-free VH domain is suitable for intracellular studies and use it to construct a high-diversity phage display library. Using this library and affinity maturation techniques we identify VH domains with picomolar affinity against eIF4E, a protein commonly hyper-activated in cancer. We demonstrate that these molecules interact with eIF4E at the eIF4G binding site via a distinct structural pose. Intracellular overexpression of these miniproteins reduce cellular proliferation and expression of malignancy-related proteins in cancer cell lines. The linkage of high-diversity in vitro libraries with an intracellularly expressible miniprotein scaffold will facilitate the discovery of VH domains suitable for intracellular applications.

Approaches have been devised to increase the discovery rate of intrabodies but often these yield results that aren’t functional in cells. Here the authors engineer and optimise an autonomous and disulphide-free human VH domain for intracellular expression, and they identify several VH domain binders against eIF4E.

Overexpression of p-4EBP1 associates with p-eIF4E and predicts poor prognosis for non-small cell lung cancer patients with resection

Eukaryotic initiation factor 4E (eIF4E) and its phosphorylated form (p-eIF4E) play a crucial role in the protein synthesis, both are under regulation of eIF4E-binding protein 1 (4EBP1) and mitogen-activated protein kinase (MAPK)-interacting kinases (MNKs). This study aims to explore the potential prognostic significance of p-4EBP1 and p-eIF4E in NSCLC patients. The expression of p-4EBP1 and p-eIF4E in NSCLC patients was detected by immunohistochemistry (IHC) staining in tissue microarrays (TMAs) containing 354 NSCLC and 53 non-cancerous lung tissues (Non-CLT). The overexpression percentage of p-4EBP1 and p-eIF4E in lung squamous cell carcinoma (SCC) and adenocarcinoma (ADC) was significantly higher than that of Non-CLT. P-4EBP1 expression in patients with advanced clinical stage was higher than that in early stage. Expression of p-4EBP1 had a positive relationship with p-eIF4E expression both in lung SCC and ADC. NSCLC patients with high expression of p-4EBP1 and p-eIF4E alone or in combination had a lower survival rate than that of other phenotypes. For NSCLC patients, p-4EBP1 is an independent poor prognostic factor as well as clinical stage, LNM and pathological grade. Overexpression of p-4EBP1 and p-eIF4E might be novel prognostic marker for NSCLC, who possesses potential application value for NSCLC targeted therapy.

Nuclear-targeted 4E-BP1 is dephosphorylated, induces nuclear translocation of eIF4E, and alters mRNA translation

Mechanistic target of rapamycin complex 1 (mTORC1) phosphorylates and inhibits eukaryotic translation initiation factor 4E (eIF4E)-binding protein 1 (4E-BP1). This leads to the release of eIF4E from 4E-BP1 and the initiation of eIF4E-dependent mRNA translation. In this study, we examined the expression of a 4E-BP1-based reporter (mTORC1 activity reporter; TORCAR) with various localization signal tags to clarify the relationship between the localization of 4E-BP1 and its phosphorylation. Phosphorylation of 4E-BP1 at threonine 37/46 and serine 65 was efficient at lysosomes and the plasma membrane, whereas it was significantly decreased in the nucleus. In addition, the localization of endogenous eIF4E shifted from the cytoplasm to the nucleus only when nuclear-localized TORCAR was expressed. Nuclear-localized TORCAR decreased cyclin D1 protein levels and altered cell cycle distribution. These data provide an experimental tool to manipulate the localization of endogenous eIF4E without affecting mTORC1 and highlight the important role of nuclear-cytoplasmic shuttling of eIF4E.

Pharmacodynamic and therapeutic pilot studies of single-agent ribavirin in patients with human papillomavirus-related malignancies

OBJECTIVES

Ribavirin inhibits eukaryotic translation initiation factor 4E (eIF4E), thereby decreasing cap-dependent translation. In this two-part study, we assessed the pharmacodynamic effects and therapeutic potential of ribavirin in human papillomavirus (HPV)-related malignancies.

METHODS

In the pharmacodynamic study, ribavirin (400 mg BID for 14 days) was evaluated in 8 patients with HPV-positive localized oropharyngeal carcinoma with phosphorylated-eIF4E (p-eIF4E) ≥ 30%. In the therapeutic study, ribavirin (1400 mg BID in 28-day cycles, continuously dosed) was evaluated in 12 patients with recurrent and/or metastatic HPV-related cancer. Dose interruptions or reductions were allowed according to prespecified criteria. Toxicities were assessed in accordance with National Cancer Institute Common Terminology Criteria for Adverse Events version 4; response was assessed using Response Evaluation Criteria in Solid Tumors version 1.1. Patients remained on study until disease progression or unacceptable toxicity.

RESULTS

Six patients were evaluable in the pharmacodynamic study: 4 had decreased p-eIF4E after 14 days of ribavirin. In the therapeutic study, 12 patients were evaluable for toxicity, and 9 were evaluable for response. Among these, median follow-up was 3.5 months, and best overall response was stable disease in 5 patients and progression of disease in 4 patients. Median progression-free survival was 1.8 months. The most common treatment-related adverse events (grade > 2) were anemia, dyspnea, and hyperbilirubinemia. All patients had anemia (grades 1-3), with 33% having at least 1 dose reduction.

CONCLUSION

Oral ribavirin decreases p-eIF4E levels and is well-tolerated. However, a clear signal of efficacy in patients with recurrent and/or metastatic HPV-related cancers was not observed. (NCT02308241, NCT01268579).

Outcome of Patients With Head and Neck Squamous Cell Carcinoma Can be Predicted by Expression of eIF4E and Osteopontin in Free Surgical Margins

Squamous cell carcinoma of the head and neck (HNSCC) is recognized as the third most common cause of death. Incomplete resection of the primary tumor is the main cause of local recurrence and poor prognosis in HNSCC. Histologic assessment in order to determine "tumor-free" margins could be inadequate because of malignant transformation occurs at the molecular level earlier than the morphologic level. The present study aimed to evaluate the prognostic significance of eukaryotic initiation factor 4E (eIF4E) and Osteopontin in the tumor cells and histologically tumor free surgical margins of HNSCC. This cohort study was performed on 60 cases of HNSCC diagnosed at the Department of Pathology and treated at the Clinical Oncology Department, Faculty of Medicine, Zagazig University. Our enrolled formalin fixed paraffin embedded biopsy specimens with their matched tumor free surgical margins from resected head and neck squamous cell carcinoma were immunostaind for eIF4E and Osteopontin markers. 65% of our HNSCC patients had eIF4 E positive cytoplasmic immunostaining and 70% of them exhibited Osteopontin staining. Two-thirds of the dead patients exhibited high Osteopontin positive staining, whereas the surviving group did not exhibit this high expression. Concerning eIF4E, 85% and 5% of the dead patients showed high and low eIF4E expression, respectively. Disease-free survival (DFS) and overall survival were significantly (P=0.000) different between high and negative expression of Osteopontin, high and negative expression of eIF4E. 84% of patients with eIF4E positive margins and 75% with Osteopontin positive margins had local recurrence. In addition, negative expression of eIF4E is associated with highly significant better DFS and overall survival (P=0.000 and 0.001), respectively, in the margin negative expression status, while negative expression of Osteopontin was significantly associated with better DFS but of no significance in overall survival outcome. Our findings suggest that tumor-free surgical margins in HNSCC may be redefined as histologically Osteopontin and eIF4E negative resection margins. However, multicenter prospective studies are required to further evaluate their clinical utility in the surgical management of primary HNSCC.

Supraphysiological activation of TAK1 promotes skeletal muscle growth and mitigates neurogenic atrophy

Skeletal muscle mass is regulated through coordinated activation of multiple signaling pathways. TAK1 signalosome has been found to be activated in various conditions of muscle atrophy and hypertrophy. However, the role and mechanisms by which TAK1 regulates skeletal muscle mass remain less understood. Here, we demonstrate that supraphysiological activation of TAK1 in skeletal muscle of adult mice stimulates translational machinery, protein synthesis, and myofiber growth. TAK1 causes phosphorylation of elongation initiation factor 4E (eIF4E) independent of mTOR. Inactivation of TAK1 disrupts neuromuscular junction morphology and causes deregulation of Smad signaling. Using genetic approaches, we demonstrate that TAK1 prevents excessive loss of muscle mass during denervation. TAK1 favors the nuclear translocation of Smad4 and cytoplasmic retention of Smad6. TAK1 is also required for the phosphorylation of eIF4E in denervated skeletal muscle. Collectively, our results demonstrate that TAK1 supports skeletal muscle growth and prevents neurogenic muscle atrophy in adult mice.

TGF-β-activated kinase 1 (TAK1) is essential for the maintenance of skeletal muscle mass through incompletely understood mechanisms. Here the authors show that supraphysiological activation of TAK1 leads to muscle hypertrophy through the elongation initiation factor 4E (eIF4E) involved in protein synthesis, and prevents denervation-induced atrophy in mice.

Epigenetic regulation of EIF4A1 through DNA methylation and an oncogenic role of eIF4A1 through BRD2 signaling in prostate cancer

In prostate cancers, elongation initiation factor 4A1 (eIF4A1) supports an oncogenic translation program and is highly expressed, but its role remains elusive. By use of human specimens and cell models, we addressed the role of eIF4A1 in prostate cancer in vitro and in vivo. EIF4A1 expression, as determined by mRNA and protein levels, was higher in primary prostate cancers relative to normal prostate tissue. Also, for primary prostate cancers, elevated mRNA levels of EIF4A1 correlated with DNA hypomethylation levels in the CpG-rich island of EIF4A1. Using a DNMT3a CRISPR-Cas9-based tool for specific targeting of DNA methylation, we characterized, in human prostate cancer cells, the epigenetic regulation of EIF4A1 transcripts through DNA methylation in the CpG-rich island of EIF4A1. Next, we investigated the oncogenic effect of EIF4A1 on cancer cell proliferation in vitro and tumor growth in vivo. For prostate cancer cells, EIF4A1 heterozygous knockout or knockdown inhibited protein translation and tumor growth. In addition, using RNA immunoprecipitation with RNA sequencing, we discovered the eIF4A1-mediated translational regulation of the oncogene BRD2, which contains the most enriched eIF4A1-binding motifs in its 5’ untranslated region, establishing an eIF4A1-BRD2 axis for oncogenic translation. Finally, we found a positive correlation between expression levels of eIF4A1 and BRD2 in primary prostate cancers. Our results demonstrate, for prostate cancer cells, epigenetic regulation of EIF4A1 transcripts through DNA methylation and an oncogenic roles of eIF4A1 through BRD2 signaling.

Pre-mRNA processing factor 19 functions in DNA damage repair and radioresistance by modulating cyclin D1 in hepatocellular carcinoma

Pre-mRNA processing factor 19 (PRP19) is elevated in hepatocellular carcinoma (HCC); however, little is known about its function in DNA damage repair in HCC. In this study, analysis of The Cancer Genome Atlas data and our tumor models after ionizing radiation (IR) treatment indicated that increased expression of PRP19 was positively correlated with DNA damage repair. Gain of PRP19 expression induced by plasmids resulted in decreases in apoptosis and double-strand breaks (DSBs), and an increase in cell survival after IR. Loss of PRP19 expression induced by small interfering RNAs resulted in the accumulation of apoptosis and DSBs, and a decrease in cell survival. Mechanistically, the effect of PRP19 on DNA damage repair was mediated by the modulation of cyclin D1 expression in HCC. PRP19 controlled the translation of cyclin D1 by modulating eukaryotic initiation factor 4E. PRP19 affected the DNA damage repair ability of cyclin D1 by interacting with the WD40 domain. The combination of PRP19 and cyclin D1 was more valuable than each single marker for predicting the prognosis of patients. Taken together, the present results demonstrate that PRP19 promotes DNA damage repair by modulating cyclin D1 expression and function, thereby contributing to the radioresistance in HCC.

Targeting Ribosome Biogenesis to Combat Tamoxifen Resistance in ER+ve Breast Cancer

Simple Summary

Resistance to tamoxifen treatment is an obstacle for ER+ve breast cancer therapy. The overexpression of c-MYC is a known driver of cancer progression and is associated with tamoxifen resistance. Through mediating the up-regulation of ribosome biogenesis and alteration of the transcriptome, c-MYC modulates the translation profile to facilitate the development of tamoxifen resistance. c-MYC is, however, undruggable. Thus, targeting downstream mechanisms mediated by c-MYC might be a more feasible approach. Studies have demonstrated that inhibition of ribosome biogenesis can achieve tumour suppression. Targeting ribosome biogenesis may thus be a feasible strategy to reverse tamoxifen resistance. This article reviews the current evidence to support the feasibility of suppressing ribosome biogenesis to reverse tamoxifen resistance in ER+ve breast cancer.

Abstract

Breast cancer is a heterogeneous disease. Around 70% of breast cancers are estrogen receptor-positive (ER+ve), with tamoxifen being most commonly used as an adjuvant treatment to prevent recurrence and metastasis. However, half of the patients will eventually develop tamoxifen resistance. The overexpression of c-MYC can drive the development of ER+ve breast cancer and confer tamoxifen resistance through multiple pathways. One key mechanism is to enhance ribosome biogenesis, synthesising mature ribosomes. The over-production of ribosomes sustains the demand for proteins necessary to maintain a high cell proliferation rate and combat apoptosis induced by therapeutic agents. c-MYC overexpression can induce the expression of eIF4E that favours the translation of structured mRNA to produce oncogenic factors that promote cell proliferation and confer tamoxifen resistance. Either non-phosphorylated or phosphorylated eIF4E can mediate such an effect. Since ribosomes play an essential role in c-MYC-mediated cancer development, suppressing ribosome biogenesis may help reduce aggressiveness and reverse tamoxifen resistance in breast cancer. CX-5461, CX-3543 and haemanthamine have been shown to repress ribosome biogenesis. Using these chemicals might help reverse tamoxifen resistance in ER+ve breast cancer, provided that c-MYC-mediated ribosome biogenesis is the crucial factor for tamoxifen resistance. To employ these ribosome biogenesis inhibitors to combat tamoxifen resistance in the future, identification of predictive markers will be necessary.

Discovery of an eIF4A Inhibitor with a Novel Mechanism of Action

Increased protein synthesis is a requirement for malignant growth, and as a result, translation has become a pharmaceutical target for cancer. The initiation of cap-dependent translation is enzymatically driven by the eukaryotic initiation factor (eIF)4A, an ATP-powered DEAD-box RNA-helicase that unwinds the messenger RNA secondary structure upstream of the start codon, enabling translation of downstream genes. A screen for inhibitors of eIF4A ATPase activity produced an intriguing hit that, surprisingly, was not ATP-competitive. A medicinal chemistry campaign produced the novel eIF4A inhibitor 28, which decreased BJAB Burkitt lymphoma cell viability. Biochemical and cellular studies, molecular docking, and functional assays uncovered that 28 is an RNA-competitive, ATP-uncompetitive inhibitor that engages a novel pocket in the RNA groove of eIF4A and inhibits unwinding activity by interfering with proper RNA binding and suppressing ATP hydrolysis. Inhibition of eIF4A through this unique mechanism may offer new strategies for targeting this promising intersection point of many oncogenic pathways.

Activation of ERK and p38 Reduces AZD8055-Mediated Inhibition of Protein Synthesis in Hepatocellular Carcinoma HepG2 Cell Line

Protein synthesis is important for maintaining cellular homeostasis under various stress responses. In this study, we screened an anticancer drug library to select compounds with translational repression functions. AZD8055, an ATP-competitive mechanistic target of rapamycin complex 1/2 (mTORC1/2) inhibitor, was selected as a translational suppressor. AZD8055 inhibited protein synthesis in mouse embryonic fibroblasts and hepatocellular carcinoma HepG2 cells. Extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) were activated during the early phase of mTORC1/2 inhibition by AZD8055 treatment. Combined treatment of AZD8055 with the MAPK kinase1/2 (MEK1/2) inhibitor refametinib or the p38 inhibitor SB203580 markedly decreased translation in HepG2 cells. Thus, the inhibition of ERK1/2 or p38 may enhance the efficacy of AZD8055-mediated inhibition of protein synthesis. In addition, AZD8055 down-regulated the phosphorylation of eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), and AZD8055-induced phosphorylation of ERK1/2 and p38 had no effect on phosphorylation status of 4E-BP1. Interestingly, AZD8055 modulated the 4E-BP1 mRNA pool by up-regulating ERK1/2 and p38 pathways. Together, these results suggest that AZD8055-induced activation of MAPKs interferes with inhibition of protein synthesis at an early stage of mTORC1/2 inhibition, and that it may contribute to the development of resistance to mTORC1/2 inhibitors.

The Clinical Implications and Molecular Mechanism of CX3CL1 Expression in Urothelial Bladder Cancer

Background

CX3CL1 is a chemokine that may play important roles in cancer immune regulation. Its mechanism in bladder cancer (BCa) is poorly understood. The objective of the current study was to evaluate the association between CX3CL1 and BCa and the related biological mechanisms.

Methods

A total of 277 patients with BCa were enrolled in the present study. The association between CX3CL1 expression and disease outcome was evaluated. In vitro and in vivo experiments were performed using the TCCSUP cell line to investigate the function of CX3CL1 in BCa.

Results

Compared with low expression, high expression of CX3CL1 was significantly associated with poorer progression-free survival (hazard ratio [HR]=2.03, 95% confidence interval [95% CI]: 1.26-3.27, P=0.006), cancer-specific survival (HR=2.16, 95% CI: 1.59-2.93, P<0.001), and overall survival (HR=1.55, 95% CI: 1.08-2.24, P=0.039). Multivariable Cox regression analysis suggested that CX3CL1 was an independent prognostic factor for BCa outcomes. In vitro and in vivo experiments indicated that high expression of CX3CL1 was significantly associated with cell proliferation (P<0.001) and invasion (P<0.001). Gene expression profiling results showed that after CX3CL1 knockdown, CDH1 was significantly upregulated, while ETS1, RAF1, and EIF4E were significantly downregulated. Pathway enrichment analysis suggested that the ERK/MAPK signaling pathway was significantly inhibited (P<0.001).

Conclusions

CX3CL1 is an independent predictor of a poor prognosis in BCa and can promote the proliferation and invasion of BCa cells.

High-risk human papillomavirus-18 uses an mRNA sequence to synthesize oncoprotein E6 in tumors

Cervical cancer is the fourth most common cause of cancer in women worldwide in terms of both incidence and mortality. Persistent infection with high-risk types of human papillomavirus (HPV), namely 16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59, and 68, constitute a necessary cause for the development of cervical cancer. Viral oncoproteins E6 and E7 play central roles in the carcinogenic process by virtue of their interactions with cell master proteins such as p53, retinoblastoma (Rb), mammalian target of rapamycin (mTOR), and c-MYC. For the synthesis of E6 and E7, HPVs use a bicistronic messenger RNA (mRNA) that has been studied in cultured cells. Here, we report that in cervical tumors, HPV-18, -39, and -45 transcribe E6/E7 mRNAs with extremely short 5' untranslated regions (UTRs) or even lacking a 5' UTR (i.e., zero to three nucleotides long) to express E6. We show that the translation of HPV-18 E6 cistron is regulated by the motif ACCaugGCGCG(C/A)UUU surrounding the AUG start codon, which we term Translation Initiation of Leaderless mRNAs (TILM). This motif is conserved in all HPV types of the phylogenetically coherent group forming genus alpha, species 7, which infect mucosal epithelia. We further show that the translation of HPV-18 E6 largely relies on the cap structure and eIF4E and eIF4AI, two key translation initiation factors linking translation and cancer but does not involve scanning. Our results support the notion that E6 forms the center of the positive oncogenic feedback loop node involving eIF4E, the mTOR cascade, and p53.

The role of proteomics in the multiplexed analysis of gene alterations in human cancer

INTRODUCTION

Proteomics has played a pivotal role in identifying proteins perturbed in disease conditions when compared with healthy samples. Study of dysregulated proteins aids in identifying diagnostic markers and potential therapeutic targets. Cancer is an outcome of interplay of several such disarrayed proteins and molecular pathways which perturb cellular homeostasis, resulting in transformation. In this review, we discuss various facets of proteomic approaches, including tools and technological advancements, aiding in understanding differentially expressed molecules and signaling mechanisms.

AREAS COVERED

In this review, we have taken the approach of documenting the different methods of proteomic studies, ranging from labeling techniques, data analysis methods, and the nature of molecule detected. We summarize each technique and provide a glimpse of cancer research carried out using them, highlighting the advantages and drawbacks in comparison with others. Literature search using online resources, such as PubMed and Google Scholar were carried out for this approach.

EXPERT OPINION

Technological advancements in proteomics studies have come a long way from the study of two-dimensional mapping of proteins separated on gels in the early 1970s. Higher precision in molecular identification and quantification (high throughput), and greater number of samples analyzed have been the focus of researchers.

Expression of the HOXA gene family and its relationship to prognosis and immune infiltrates in cervical cancer

Background

The homeobox A cluster (HOXA) gene family is participated in multiple biological functions in human cancers. To date, little is known about the expression profile and clinical significance of HOXA genes in cervical cancer.

Methods

We downloaded RNASeq data of cervical cancer from The Cancer Genome Atlas (TCGA) database. The difference in HOXA family expression was analyzed using independent samples t test. Cox proportional hazard regression analysis was used to assess the effect of HOXA family expression on survival, and a nomogram predicting survival was generated. We assessed the infiltration difference in immune cells and expression difference of immunity biomarkers between two groups with different expression level of HOXA genes through Immune Cell Abundance Identifier (ImmuCellAI) and independent samples t test, respectively.

Results

Our results showed that the HOXA1 gene was upregulated, while the HOXA10 and HOXA11 were downregulated in cervical cancer. Downregulation of HOXA1 was related to a poor outcome for cervical cancer patient. We also identified a significantly increased abundance of T helper 2 cells (Th2) and higher expression of PD‐L1 in cervical cancer patients with lower expression of HOXA10 and HOXA11. The gene set enrichment analysis (GSEA) results indicated that HOXA1 and HOXA11 were involved in immune responses pathways and participated in the activation of a variety of classic signaling pathways related to the progression of human cancer.

Conclusion

This study comprehensively analyzed different HOXA genes applying public database to determine their expression patterns, potential diagnostic, prognostic, and treatment values in cervical cancer.

Identification of Novel Therapeutic Targets for Fibrolamellar Carcinoma Using Patient-Derived Xenografts and Direct-from-Patient Screening

To repurpose therapeutics for fibrolamellar carcinoma (FLC), we developed and validated patient-derived xenografts (PDX) from surgical resections. Most agents used clinically and inhibitors of oncogenes overexpressed in FLC showed little efficacy on PDX. A high-throughput functional drug screen found primary and metastatic FLC were vulnerable to clinically available inhibitors of TOPO1 and HDAC and to napabucasin. Napabucasin's efficacy was mediated through reactive oxygen species and inhibition of translation initiation, and specific inhibition of eIF4A was effective. The sensitivity of each PDX line inversely correlated with expression of the antiapoptotic protein Bcl-xL, and inhibition of Bcl-xL synergized with other drugs. Screening directly on cells dissociated from patient resections validated these results. This demonstrates that a direct functional screen on patient tumors provides therapeutically informative data within a clinically useful time frame. Identifying these novel therapeutic targets and combination therapies is an urgent need, as effective therapeutics for FLC are currently unavailable. SIGNIFICANCE: Therapeutics informed by genomics have not yielded effective therapies for FLC. A functional screen identified TOPO1, HDAC inhibitors, and napabucasin as efficacious and synergistic with inhibition of Bcl-xL. Validation on cells dissociated directly from patient tumors demonstrates the ability for functional precision medicine in a solid tumor.This article is highlighted in the In This Issue feature, p. 2355.

Control of the eIF4E activity: structural insights and pharmacological implications

The central role of eukaryotic translation initiation factor 4E (eIF4E) in controlling mRNA translation has been clearly assessed in the last decades. eIF4E function is essential for numerous physiological processes, such as protein synthesis, cellular growth and differentiation; dysregulation of its activity has been linked to ageing, cancer onset and progression and neurodevelopmental disorders, such as autism spectrum disorder (ASD) and Fragile X Syndrome (FXS). The interaction between eIF4E and the eukaryotic initiation factor 4G (eIF4G) is crucial for the assembly of the translational machinery, the initial step of mRNA translation. A well-characterized group of proteins, named 4E-binding proteins (4E-BPs), inhibits the eIF4E–eIF4G interaction by competing for the same binding site on the eIF4E surface. 4E-BPs and eIF4G share a single canonical motif for the interaction with a conserved hydrophobic patch of eIF4E. However, a second non-canonical and not conserved binding motif was recently detected for eIF4G and several 4E-BPs. Here, we review the structural features of the interaction between eIF4E and its molecular partners eIF4G and 4E-BPs, focusing on the implications of the recent structural and biochemical evidence for the development of new therapeutic strategies. The design of novel eIF4E-targeting molecules that inhibit translation might provide new avenues for the treatment of several conditions.

Update on the Development of MNK Inhibitors as Therapeutic Agents

Mitogen-activated protein kinase-interacting kinases 1 and 2 (MNK1/2) represent a central class of enzymes that are activated by extracellular signal-regulated kinase (ERK) or p38 mitogen-activated protein (MAP) kinases. MNK1 and MNK2 coordinate cellular signaling, control production of inflammatory chemokines, and regulate cell proliferation and survival. MNK1/2 are referred to as serine/threonine kinases as they phosphorylate serine or threonine residues on their substrates. Upon activation, MNK1/2 phosphorylate eukaryotic translation initiation factor 4E (eIF4E) at Ser209, which in turn initiates ribosome assembly and protein translation. Deleterious overexpression of MNK1/2 and/or eIF4E have been reported in several diseases including cancers, neurological disorders, autism, and inflammation. Recently, there have been intense efforts toward the development of potent and selective inhibitors of MNK1/2 in both academia and industry. Herein, we review the current understanding of the structural and biological aspects of MNK1/2 and provide an update of pharmacological inhibitors of MNK1/2 including candidates in clinical trials.

Prognostic significance of OXR1 in urothelial carcinoma: low OXR1 expression is associated with worse survival

Background: Bioinformatic analysis has revealed that OXR1 is significantly downregulated in muscle-invasive bladder cancer. Patients & methods: The expression of OXR1 in patients with urothelial carcinoma was evaluated by immunohistochemistry, including 340 cases with urothelial carcinoma in the upper urinary tract and 295 in the urinary bladder. Results: Low expression of OXR1 was significantly correlated with adverse pathological parameters including high primary tumor (pT) stage, high node stage, high histological grade, high mitotic activity and increased vascular or perineural invasion (all p < 0.05). Low expression of OXR1 independently predicted worse metastasis-free survival (p = 0.033) in urothelial carcinoma of the upper urinary tract and worse disease-specific survival (p = 0.022) and metastasis-free survival (p < 0.001) in urothelial carcinoma of the urinary bladder. Conclusion: Low expression of OXR1 is an adverse prognostic factor in urothelial carcinoma.

LPS/TLR4 pathways in breast cancer: insights into cell signalling

BACKGROUND

Cancer cells are usually recognized as foreign particles by the immune cells. Mounting evidences suggest important link between toll like receptors (TLRs) and carcinogenesis. This review article focused on the role of TLRs, especially TLR4 in breast cancer. <p> Methods: Research data on TLRs and cancer was explored in PubMed, Scopus, Google Scholar, and reviewed. Although some pioneer works are referenced, papers published in last ten years were mostly cited. <p> Results: TLRs are widely investigated pattern recognition receptors (PRR), and TLR4 is the most studied TLRs, implicated with occurrence of several types of cancers including breast cancer. TLR4 activation occurs via the binding of its ligand lipopolysaccharide (LPS), a component of the outer membrane of gram negative bacteria. Upon LPS binding, TLR4 dimerizes and recruits downstream signalling and/or adapter molecules leading to gene expression related to cancer cell proliferation, survival, invasion, and metastasis. Although LPS/TLR4 signalling seems a single signal transduction pathway, the TLR4 activation results in the activation of multiple diverse intracellular networks with huge cellular responses in both immune and cancer cells. The role of TLR4 in growth, invasion and metastasis of breast cancer is attracting huge attention in oncology research. Several clinical and preclinical studies utilize both TLR4 agonists and antagonists as treatment option for cancer therapy either as monotherapy or adjuvants for vaccine development. <p> Conclusion: This review narrates the role of LPS/TLR4 signalling in breast cancer development and future prospective for targeting LPS/TLR4 axis in the treatment of breast cancer.

RAD001 targeted HUVECs reverses 12-lipoxygenase-induced angiogenesis in oesophageal squamous cell carcinoma

12‐LOX plays an important role in the progression of various malignancies. However, the underlying mechanisms of the action of 12‐LOX and tumour treatment strategies remain not fully defined. In this study, we investigated the possible roles of 12‐LOX in ESCC and explored the new therapeutic target. Approximately 73% of ESCC tissues showed marked up‐regulation of 12‐LOX, which was associated with poor prognosis. 12‐LOX overexpression was positively correlated with the malignant progression of ESCC as demonstrated both in vitro and in vivo. Up‐regulation of 12‐LOX significantly increased the proliferation of ESCC cells and the xenograft volume. Moreover, 12‐LOX up‐regulation promoted tube formation of HUVECs and tumour angiogenesis in xenografts. Mechanism investigation indicated that 12‐LOX overexpression led to activation of the PI3K/AKT/mTOR pathway and the up‐regulation of VEGF in ESCC cells. Subsequent analysis indicated that the RAD001 could reverse the 12‐LOX‐induced promoting effect on ESCC. Specifically, the application of RAD001 inhibited the proliferation of ESCC cells and the tube‐forming ability of HUVECs. In the drug group, the xenografts exhibited significant volume reduction and angiogenesis inhibition. We demonstrated that RAD001 could inhibit HUVEC migration. These findings presented the evidence that RAD001 had distinct roles on HUVECs and could exert anti‐tumour effects by targeting not only the PI3K/AKT/mTOR pathway but the angiogenesis in ESCC.

The regulation of polyamine pathway proteins in models of skeletal muscle hypertrophy and atrophy: a potential role for mTORC1

Polyamines have been shown to be absolutely required for protein synthesis and cell growth. The serine/threonine kinase, the mechanistic target of rapamycin complex 1 (mTORC1), also plays a fundamental role in the regulation of protein turnover and cell size, including in skeletal muscle, where mTORC1 is sufficient to increase protein synthesis and muscle fiber size, and is necessary for mechanical overload-induced muscle hypertrophy. Recent evidence suggests that mTORC1 may regulate the polyamine metabolic pathway, however, there is currently no evidence in skeletal muscle. This study examined changes in polyamine pathway proteins during muscle hypertrophy induced by mechanical overload (7 days), with and without the mTORC1 inhibitor, rapamycin, and during muscle atrophy induced by food deprivation (48 h) and denervation (7 days) in mice. Mechanical overload induced an increase in mTORC1 signaling, protein synthesis and muscle mass, and these were associated with rapamycin-sensitive increases in adenosylmethione decarboxylase 1 (Amd1), spermidine synthase (SpdSyn), and c-Myc. Food deprivation decreased mTORC1 signaling, protein synthesis, and muscle mass, accompanied by a decrease in spermidine/spermine acetyltransferase 1 (Sat1). Denervation, resulted increased mTORC1 signaling and protein synthesis, and decreased muscle mass, which was associated with an increase in SpdSyn, spermine synthase (SpmSyn), and c-Myc. Combined, these data show that polyamine pathway enzymes are differentially regulated in models of altered mechanical and metabolic stress, and that Amd1 and SpdSyn are, in part, regulated in a mTORC1-dependent manner. Furthermore, these data suggest that polyamines may play a role in the adaptive response to stressors in skeletal muscle.

Co-Operativity between MYC and BCL-2 Pro-Survival Proteins in Cancer

B-Cell Lymphoma 2 (BCL-2), c-MYC and related proteins are arguably amongst the most widely studied in all of biology. Every year there are thousands of papers reporting on different aspects of their biochemistry, cellular and physiological mechanisms and functions. This plethora of literature can be attributed to both proteins playing essential roles in the normal functioning of a cell, and by extension a whole organism, but also due to their central role in disease, most notably, cancer. Many cancers arise due to genetic lesions resulting in deregulation of both proteins, and indeed the development and survival of tumours is often dependent on co-operativity between these protein families. In this review we will discuss the individual roles of both proteins in cancer, describe cancers where co-operativity between them has been well-characterised and finally, some strategies to target these proteins therapeutically.

The relationship between NFKB, HER2, ER expression and anthracycline -based neoadjuvan chemotherapy response in local advanced stadium breast cancer: A cohort study in Eastern Indonesia

Introduction

Neoadjuvant chemotherapy has become the standard form of treatment for locally advanced breast cancer. Chemoresistence is a problem that limits the effectiveness of chemotherapy. Therefore, predictive biomarkers are needed to choose the appropriate chemotherapy to the right patient. The role of NF-кb expression as a predictive biomarker of neoadjuvant chemotherapy response needs to be investigated in patients with locally advanced breast cancer who are treated with a regimen of cyclophosphamide-doxorubicin-5FU (CAF).

Methods

This observational study used the prospective cohort method to examine 62 samples. CAF was administered at 3-week intervals for 3 cycles of chemotherapy. The data utilized in this study include the positive and negative expression of NF-κB, ER, and HER2 overexpression. The cases were divided into groups that were responsive and non-responsive to the neoadjuvant chemotherapy.

Results

The average age in the youngest group was 26 years, and that in the oldest was 66 years. The highest age group was subjects in their 50s, which had 26 cases (41.9%). The majority of the cases were moderate grade with 38 cases (61.3%). The percentage of responsive subjects was higher in the groups with negative NF-κB expression (82.5%), positive HER2 status (85.7%), and negative ER status (71.9%). It was found that 37 cases (59.7%) were responsive to CAF, while 25 cases (40.3%) were non-responsive. There was a significant relationship between NF-κB expression and chemotherapy response (p < 0.05), and the percentage of responsive subjects was higher among those with negative NF-κB expression (82.5%) than positive NF-κB expression (18.2%).

Conclusion

NF-κB expression, ER status, and HER2 have a significant relationship with the response to anthracycline-based neoadjuvant chemotherapy for local advanced breast cancer, and NF-κB expression has the most significant relationship with the chemotherapy response. Therefore, NF-κB expression should be considered as a predictive biomarker for the response to CAF regimens.

The PI3K/Akt/mTORC signaling axis in head and neck squamous cell carcinoma: Possibilities for therapeutic interventions either as single agents or in combination with conventional therapies

The latest advances in the sequencing methods in head and neck squamous cell carcinoma (HNSCC) tissues have revolutionized our understanding of the disease by taking off the veil from the most frequent genetic alterations in the components of the oncogenic pathways. Among all the identified alterations, aberrancies in the genes attributed to the phosphoinositide 3-kinases (PI3K) axis have attracted special attention as they were altered in more than 90% of the tissues isolated from HNSCC patients. In fact, the association between these aberrancies and the increased risk of cancer metastasis suggested this axis as an "Achilles Heel" of HNSCC, which may be therapeutically targeted. The results of the clinical trials investigating the therapeutic potential of the inhibitors targeting the components of the PI3K axis in the treatment of HNSCC patients, either alone or in a combined-modal strategy, opened a new chapter in the treatment strategy of this malignancy. The present study aimed to review the importance of the PI3K axis in the pathogenesis of HNSCC and also provide a piece of information about the breakthroughs and challenges of PI3K inhibitors in the therapeutic strategies of the disease.

eIF4E Overexpression Is Associated with Poor Prognoses of Ovarian Cancer

Aim

Ovarian cancer is a common malignant tumor of the gynecological oncology worldwide, with a high incidence and mortality rate and poor prognosis. Searching for new diagnostic molecular biomarkers for ovarian cancer is extremely significant.

Methods

Here, we analyzed the expression rates of eIF4E and cyclin D1 proteins in 123 cases of cancer tissue samples and 38 cases of paracancerous tissue samples and studied the connection between the expression rates of eIF4E and cyclin D1 proteins by immunohistochemistry and statistically correlated with clinicopathological features in ovarian cancer.

Results

The results showed that the expression rates of eIF4E and cyclin D1 proteins in ovarian cancer tissues were significantly higher than those in noncancerous epithelial ovarian tissues (P = 0.001 and P = 0.032, respectively). Additionally, the results revealed that a higher expression rate of eIF4E (P = 0.008) was found in the advanced stage (stage III/IV), and also patients with cervical lymph node metastasis displayed higher expression of eIF4E (P < 0.001) and cyclin D1 (P = 0.033) than those without lymph node metastasis. Spearman's rank correlation test showed that there was a significant positive correlation between the eIF4E and cyclin D1 proteins in ovarian cancer. The Kaplan-Meier method showed that patients with lower expression of eIF4E had marginally better survival than those with high expression of eIF4E (P = 0.012). Multivariate Cox regression analysis further identified that positive expression of eIF4E was an independent prognostic factor.

Conclusion

In ovarian cancer, eIF4E might be a valuable biomarker to predict poor prognoses and a potential therapeutic target to develop valid treatment strategies.