Inhibition of mTOR/eIF4E by anti-viral drug ribavirin effectively enhances the effects of paclitaxel in oral tongue squamous cell carcinoma

Enhancement of Chemotherapy Efficacy in Cervical Cancer via MAPK Pathway Inhibition by Osimertinib

Addressing recurrent cervical cancer poses a substantial challenge. Osimertinib, an FDA-approved EGFR inhibitor, has emerged as a promising option. Our study examined its potential to enhance paclitaxel's efficacy against cervical cancer. Osimertinib effectively hindered cancer cell growth and induced apoptosis across multiple cell lines. Combined with paclitaxel, it exhibited synergy in suppressing cervical cancer cells. Importantly, osimertinib's inhibitory effect was EGFR-independent; it targeted Mnk phosphorylation, reducing eIF4E activity. In mice, the combined osimertinib-paclitaxel treatment surpassed individual drugs in inhibiting cancer growth. These preclinical findings suggest osimertinib's repurposing as a means to improve paclitaxel's effectiveness in cervical cancer treatment.

Effect of anti-COVID-19 drugs on patients with cancer

The clinical treatment of patients with cancer who are also diagnosed with coronavirus disease (COVID-19) has been a challenging issue since the outbreak of COVID-19. Therefore, it is crucial to understand the effects of commonly used drugs for treating COVID-19 in patients with cancer. Hence, this review aims to provide a reference for the clinical treatment of patients with cancer to minimize the losses caused by the COVID-19 pandemic. In this study, we also focused on the relationship between COVID-19, commonly used drugs for treating COVID-19, and cancer. We specifically investigated the effect of these drugs on tumor cell proliferation, migration, invasion, and apoptosis. The potential mechanisms of action of these drugs were discussed and evaluated. We found that most of these drugs showed inhibitory effects on tumors, and only in a few cases had cancer-promoting effects. Furthermore, inappropriate usage of these drugs may lead to irreversible kidney and heart damage. Finally, we have clarified the use of different drugs, which can provide useful guidance for the clinical treatment of cancer patients diagnosed with COVID-19.

The eukaryotic translation initiation factor eIF4E unexpectedly acts in splicing thereby coupling mRNA processing with translation: eIF4E induces widescale splicing reprogramming providing system-wide connectivity between splicing, nuclear mRNA export and translation

Recent findings position the eukaryotic translation initiation factor eIF4E as a novel modulator of mRNA splicing, a process that impacts the form and function of resultant proteins. eIF4E physically interacts with the spliceosome and with some intron-containing transcripts implying a direct role in some splicing events. Moreover, eIF4E drives the production of key components of the splicing machinery underpinning larger scale impacts on splicing. These drive eIF4E-dependent reprogramming of the splicing signature. This work completes a series of studies demonstrating eIF4E acts in all the major mRNA maturation steps whereby eIF4E drives production of the RNA processing machinery and escorts some transcripts through various maturation steps. In this way, eIF4E couples the mRNA processing-export-translation axis linking nuclear mRNA processing to cytoplasmic translation. eIF4E elevation is linked to worse outcomes in acute myeloid leukemia patients where these activities are dysregulated. Understanding these effects provides new insight into post-transcriptional control and eIF4E-driven cancers.

Prognostic potential of Akt, pAkt(Ser473) and pAkt(Thr308) immunoreactivity in relation to HPV prevalence in head and neck squamous cell carcinoma patients

BACKGROUND

The prognosis of squamous cell carcinoma of head and neck (HNSCC) patients remains relatively poor over the last years. Tobacco, alcohol and active human papillomavirus (HPV) infection are involved in HNSCC development. Akt is a serine-threonine protein kinase with main phosphorylation sites at Thr308 and Ser473, which are critical to generate a high level of Akt activity.

MATERIALS AND METHODS

The aim of the study was to compare the expression and prognostic potential of total Akt and its 2 phosphorylated forms - pAkt(Ser473) and pAkt(Thr308) in relation to HPV status in HNSCC patients. The expression levels of proteins were assessed immunohistochemically. To select independent prognostic factors univariate and multivariate analyses with Cox proportional regression model were performed.

RESULTS

Among HNSCC with active HPV16 infection significantly more tumors with high Akt (67.86%, p = 0.026) and low pAkt(Ser473) (64.29%, p = 0.000) expressions were found as compared to those with HPV negativity, while there was no significant difference in the pAkt(Thr308) expression level between HPV positive and negative tumors (p = 0.359). In the whole group of HNSCC patients independent favorable prognostic factors were low T stage, low pAkt(Thr308) expression, HPV16 active infection presence (for OS and DFS) and female gender (for OS only).

CONCLUSIONS

Our results indicate an important role of pAkt(Thr308) as prognostic biomarker for HNSCC patients. There is a high probability that using Akt inhibitors would improve therapeutical benefits and treatment effectiveness, especially in HNSCC patients with high expression of pAkt.

Repurposing of Antimicrobial Agents for Cancer Therapy: What Do We Know?

The substantial costs of clinical trials, the lengthy timelines of new drug discovery and development, along the high attrition rates underscore the need for alternative strategies for finding quickly suitable therapeutics agents. Given that most approved drugs possess more than one target tightly linked to other diseases, it encourages promptly testing these drugs in patients. Over the past decades, this has led to considerable attention for drug repurposing, which relies on identifying new uses for approved or investigational drugs outside the scope of the original medical indication. The known safety of approved drugs minimizes the possibility of failure for adverse toxicology, making them attractive de-risked compounds for new applications with potentially lower overall development costs and shorter development timelines. This latter case is an exciting opportunity, specifically in oncology, due to increased resistance towards the current therapies. Indeed, a large body of evidence shows that a wealth of non-cancer drugs has beneficial effects against cancer. Interestingly, 335 drugs are currently being evaluated in different clinical trials for their potential activities against various cancers (Redo database). This review aims to provide an extensive discussion about the anti-cancer activities exerted by antimicrobial agents and presents information about their mechanism(s) of action and stage of development/evaluation.

Targeting mTOR and eIF4E: a feasible scenario in ovarian cancer therapy

Ovarian carcinoma is one of the most common causes for cancer death in women; lack of early diagnosis and acquired resistance to platinum-based chemotherapy account for its poor prognosis and high mortality rate. As with other cancer types, ovarian cancer is characterized by dysregulated signaling pathways and protein synthesis, which together contribute to rapid cellular growth and invasiveness. The mechanistic/mammalian target of rapamycin (mTOR) pathway represents the core of different signaling pathways regulating a number of essential steps in the cell, among which protein synthesis and the eukaryotic initiation factor 4E (eIF4E), the mRNA cap binding protein, is one of its downstream effectors. eIF4E is a limiting factor in translation initiation and its overexpression is a hallmark in many cancers. Because its action is regulated by a number of factors that compete for the same binding site, eIF4E is an ideal target for developing novel antineoplastic drugs. Several inhibitors targeting the mTOR signaling pathway have been designed thus far, however most of these molecules show poor stability and high toxicity in vivo. This minireview explores the possibility of targeting mTOR and eIF4E proteins, thus impacting on translation initiation in ovarian cancer, describing the most promising experimental strategies and specific inhibitors that have been shown to have an effect on other kinds of cancers.

Repurposing the FDA-Approved Antiviral Drug Ribavirin as Targeted Therapy for Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is a squamous cell carcinoma with a proclivity for systemic dissemination, leading many patients to present with advanced stage disease and fail available treatments. There is a notable lack of targeted therapies for NPC, despite working knowledge of multiple proteins with integral roles in NPC cancer biology. These proteins include EZH2, Snail, eIF4E, and IMPDH, which are all overexpressed in NPC and correlated with poor prognosis. These proteins are known to be modulated by ribavirin, an FDA-approved hepatitis C antiviral that has recently been repurposed as a promising therapeutic in several solid and hematologic malignancies. Here, we investigated the potential of ribavirin as a targeted anticancer agent in five human NPC cell lines. Using cellular growth assays, flow cytometry, BrdU cell proliferation assays, scratch wound assays, and invasion assays, we show in vitro that ribavirin decreases NPC cellular proliferation, migration, and invasion and promotes cell-cycle arrest and cell death. Modulation of EZH2, Snail, eIF4E, IMPDH, mTOR, and cyclin D1 were observed in Western blots and enzymatic activity assays in response to ribavirin treatment. As monotherapy, ribavirin reduced flank tumor growth in multiple NPC xenograft models in vivo Most importantly, we demonstrate that ribavirin enhanced the effects of radiotherapy, a central component of NPC treatment, both in vitro and in vivo Our work suggests that NPC responds to ribavirin-mediated EZH2, Snail, eIF4E, IMPDH, and mTOR changes and positions ribavirin for clinical evaluation as a potential addition to our NPC treatment armamentarium.

Targeting AKT/mTOR in Oral Cancer: Mechanisms and Advances in Clinical Trials

Oral cancer (OC) is a devastating disease that takes the lives of lots of people globally every year. The current spectrum of treatment modalities does not meet the needs of the patients. The disease heterogeneity demands personalized medicine or targeted therapies. Therefore, there is an urgent need to identify potential targets for the treatment of OC. Abundant evidence has suggested that the components of the protein kinase B (AKT)/ mammalian target of rapamycin (mTOR) pathway are intrinsic factors for carcinogenesis. The AKT protein is central to the proliferation and survival of normal and cancer cells, and its downstream protein, mTOR, also plays an indispensable role in the cellular processes. The wide involvement of the AKT/mTOR pathway has been noted in oral squamous cell carcinoma (OSCC). This axis significantly regulates the various hallmarks of cancer, like proliferation, survival, angiogenesis, invasion, metastasis, autophagy, and epithelial-to-mesenchymal transition (EMT). Activated AKT/mTOR signaling is also associated with circadian signaling, chemoresistance and radio-resistance in OC cells. Several miRNAs, circRNAs and lncRNAs also modulate this pathway. The association of this axis with the process of tumorigenesis has culminated in the identification of its specific inhibitors for the prevention and treatment of OC. In this review, we discussed the significance of AKT/mTOR signaling in OC and its potential as a therapeutic target for the management of OC. This article also provided an update on several AKT/mTOR inhibitors that emerged as promising candidates for therapeutic interventions against OC/head and neck cancer (HNC) in clinical studies.

BAP18 is involved in upregulation of CCND1/2 transcription to promote cell growth in oral squamous cell carcinoma

BACKGROUND

As a reader of histone H3K4me3, BPTF associated protein of 18 kDa (BAP18) is involved in modulation of androgen receptor action in prostate cancer. However, the function of BAP18 on oral squamous cell carcinoma (OSCC) and its molecular mechanism remains to be elusive.

METHODS

OSCC-derived cell lines carrying silenced BAP18 were established by Lentiviral infection. Quantitative PCR (qPCR), western blot, and ChIP assay were performed to detect gene transcription regulation and the possible mechanism. Colony formation, cell growth curve and xenograft tumor experiments were performed to examine cell growth and proliferation.

FINDINGS

Our study demonstrated that BAP18 was highly expressed in OSCC samples compared with that in benign. BAP18 depletion obviously influenced the expression of a series of genes, including cell cycle-related genes. We thus provided the evidence to demonstrate that BAP18 depletion significantly decreases CCND1 and CCND2 (CCND1/2) transcription. In addition, BAP18 is recruited to the promoter regions of CCND1/2, thereby facilitating the recruitment of the core subunits of MLL1 complex to the same regions, to increase histone H3K4me3 levels. Furthermore, BAP18 depletion delayed G1-S phase transition and inhibited cell growth in OSCC-derived cell lines.

INTERPRETATION

This study suggests that BAP18 is involved in modulation of CCND1/2 transcription and promotes OSCC progression. BAP18 could be a potential target for OSCC treatment and diagnosis. FUND: This work was funded by National Natural Science Foundation of China (31871286, 81872015, 31701102, 81702800, 81902889), Foundation for Special Professor of Liaoning Province, and Supported project for young technological innovation-talents in Shenyang (No. RC170541).

Ribavirin sensitizes nasopharyngeal carcinoma to 5-fluorouracil through suppressing 5-fluorouracil-induced ERK-dependent-eIF4E activation

Although overexpression of eukaryotic translation initiation factor 4E (eIF4E) is associated with enhanced growth and poor prognosis in nasopharyngeal carcinoma (NPC), the function of eIF4E in NPC response to chemotherapy has not been revealed. In this work, we demonstrate that eIF4E inhibition using both ribavirin and siRNA targets NPC cells and enhances the efficacy of 5-fluorouracil (5-FU). Mechanism studies indicate that 5-FU treatment increases phosphorylation of eIF4E in NPC cells, and this is dependent on ERK activation. eIF4E inhibition thus significantly sensitizes NPC cell response to 5-FU. Of note, ribavirin is a clinically available anti-viral drug. We show that ribavirin exhibits preferential toxicity to NPC with normal nasopharyngeal epithelial cells largely unaffected. Ribavirin acts on NPC cells via inhibiting eIF4E/Akt signaling, and the suppression of eIF4E by ribavirin are not the consequence of inhibition of eIF4E upstream signaling: Mnk and mTOR. In two independent NPC xenograft mouse models, ribavirin at well-tolerated dose that significantly inhibited NPC growth as single drug alone and its combination with 5-FU completely arrests tumor growth throughout the whole duration of treatment, without causing toxicity in mice. Our findings provide the better understanding on the role of eIF4E in NPC in response to 5-FU and preclinical rationale to explore ribavirin as a sensitizing strategy to treat NPC, particularly in those who develop 5-FU resistance.

Targeting EIF4E signaling with ribavirin in infant acute lymphoblastic leukemia

The poor outcomes in infant acute lymphoblastic leukemia (ALL) necessitate new treatments. Here we discover that EIF4E protein is elevated in most cases of infant ALL and test EIF4E targeting by the repurposed antiviral agent ribavirin, which has anticancer properties through EIF4E inhibition, as a potential treatment. We find that ribavirin treatment of actively dividing infant ALL cells on bone marrow stromal cells (BMSCs) at clinically achievable concentrations causes robust proliferation inhibition in proportion with EIF4E expression. Further, we find that ribavirin treatment of KMT2A-rearranged (KMT2A-R) infant ALL cells and the KMT2A-AFF1 cell line RS4:11 inhibits EIF4E, leading to decreases in oncogenic EIF4E-regulated cell growth and survival proteins. In ribavirin-sensitive KMT2A-R infant ALL cells and RS4:11 cells, EIF4E-regulated proteins with reduced levels of expression following ribavirin treatment include MYC, MCL1, NBN, BCL2 and BIRC5. Ribavirin-treated RS4:11 cells exhibit impaired EIF4E-dependent nuclear to cytoplasmic export and/or translation of the corresponding mRNAs, as well as reduced phosphorylation of the p-AKT1, p-EIF4EBP1, p-RPS6 and p-EIF4E signaling proteins. This leads to an S-phase cell cycle arrest in RS4:11 cells corresponding to the decreased proliferation. Ribavirin causes nuclear EIF4E to re-localize to the cytoplasm in KMT2A-AFF1 infant ALL and RS4:11 cells, providing further evidence for EIF4E inhibition. Ribavirin slows increases in peripheral blasts in KMT2A-R infant ALL xenograft-bearing mice. Ribavirin cooperates with chemotherapy, particularly L-asparaginase, in reducing live KMT2A-AFF1 infant ALL cells in BMSC co-cultures. This work establishes that EIF4E is broadly elevated across infant ALL and that clinically relevant ribavirin exposures have preclinical activity and effectively inhibit EIF4E in KMT2A-R cases, suggesting promise in EIF4E targeting using ribavirin as a means of treatment.

Cell culture models of oral mucosal barriers: A review with a focus on applications, culture conditions and barrier properties

Understanding the function of oral mucosal epithelial barriers is essential for a plethora of research fields such as tumor biology, inflammation and infection diseases, microbiomics, pharmacology, drug delivery, dental and biomarker research. The barrier properties are comprised by a physical, a transport and a metabolic barrier, and all these barrier components play pivotal roles in the communication between saliva and blood. The sum of all epithelia of the oral cavity and salivary glands is defined as the blood-saliva barrier. The functionality of the barrier is regulated by its microenvironment and often altered during diseases. A huge array of cell culture models have been developed to mimic specific parts of the blood-saliva barrier, but no ultimate standard in vitro models have been established. This review provides a comprehensive overview about developed in vitro models of oral mucosal barriers, their applications, various cultivation protocols and corresponding barrier properties.

Genetic and pharmacological inhibition of eIF4E effectively targets esophageal cancer cells and augments 5-FU's efficacy

Background

Aberrant activation of eIF4E is critically involved in the progression and chemoresistance of various cancers. Elevated expression of eIF4E has also been documented in human cancerous esophageal tissues. However, the role of eIF4E in esophageal cancer is unclear.

Methods

We analysed the levels of eIF4E expression and eIF4E function in a number of normal and cancerous esophageal cancer cell lines, and studied its underlying mechanism.

Results

We observed that eIF4E expression varies in different esophageal cancer cell lines but was significantly elevated in all tested esophageal cell lines as compared to the control cell lines. We demonstrated that eIF4E inhibition via genetic and pharmacological approaches inhibits cancer cell growth and survival. This inhibition also augments 5-flurouracil's (5-FU's) efficacy as demonstrated with both the in vitro esophageal cancer culture system and our in vivo xenograft mouse model. Of note, the sensitivity of esophageal cancer cells to ribavirin or eIF4E knockdown correlates well with the expression levels of eIF4E, demonstrating that esophageal cells with higher eIF4E expression are more sensitive to eIF4E inhibition. We further confirmed that the mechanism of action of ribavirin on esophageal cancer cells was through suppressing the Akt/mTOR/eIF4E and eIF4E-regulated pathways.

Conclusions

To our knowledge, our work is the first to demonstrate the multiple roles of eIF4E in esophageal cancer. eIF4E was shown to promote cancer cell growth and survival, and protected the cells from chemotherapy. Our work also demonstrated that ribavirin is an attractive candidate for the treatment of esophageal cancer.

Inhibition of eukaryotic translation initiation factor 4E is effective against chemo-resistance in colon and cervical cancer

Although cancer patients initially respond well to chemotherapy, they eventually develop resistance and relapse. In this work, we demonstrate that eIF4E-targeting therapy is a potential sensitizing strategy for overcoming chemoresistance and progression in cancer. We show that ribavirin, an anti-viral drug and pharmacological eIF4E inhibitor, effectively inhibits proliferation and decreases viability of paclitaxel-resistant cervical cancer and 5-FU-resistant colon cancer cells while is less toxic to human fibroblast cells. Importantly, oral administration of ribavirin significantly inhibits paclitaxel-resistant colon and 5-FU-resistant cervical cancer growth in xenograft mouse cancer model without causing significant toxicity in mice. Consistently, combination of ribavirin with paclitaxel or 5-FU sensitizes colon and cervical cancer cells to chemotherapeutic agents treatment in vitro and in vivo. We further confirm that the mechanism of the action of ribavirin in chemoresistant cancer cells is through suppressing eIF4E function. In addition, specific eIF4E knockdown via two independent siRNA mimics the effects of ribavirin in chemoresistant colon and cervical cancer cells. Cell cycle analysis indicate that ribavirin enhances the anti-proliferative effect of 5-FU by additionally arresting cells at G2/M phase via increasing cyclin B1, p-histone H3(Ser10) and Mad2 levels. Our work demonstrates that eIF4E inhibition using inhibitor or siRNA, either as single agent or in combination, could sensitize chemoresistant cancer cells to paclitaxel or 5-FU treatment and thereby improving the efficacy of chemodrug. Our findings demonstrate the therapeutic value of inhibiting eIF4E, particularly in chemoresistant cancers. Our findings also suggest ribavirin as a promising sensitizing drug for cancer treatment.

The ABC7 regimen: a new approach to metastatic breast cancer using seven common drugs to inhibit epithelial-to-mesenchymal transition and augment capecitabine efficacy

Breast cancer metastatic to bone has a poor prognosis despite recent advances in our understanding of the biology of both bone and breast cancer. This article presents a new approach, the ABC7 regimen (Adjuvant for Breast Cancer treatment using seven repurposed drugs), to metastatic breast cancer. ABC7 aims to defeat aspects of epithelial-to-mesenchymal transition (EMT) that lead to dissemination of breast cancer to bone. As add-on to current standard treatment with capecitabine, ABC7 uses ancillary attributes of seven already-marketed noncancer treatment drugs to stop both the natural EMT process inherent to breast cancer and the added EMT occurring as a response to current treatment modalities. Chemotherapy, radiation, and surgery provoke EMT in cancer generally and in breast cancer specifically. ABC7 uses standard doses of capecitabine as used in treating breast cancer today. In addition, ABC7 uses 1) an older psychiatric drug, quetiapine, to block RANK signaling; 2) pirfenidone, an anti-fibrosis drug to block TGF-beta signaling; 3) rifabutin, an antibiotic to block beta-catenin signaling; 4) metformin, a first-line antidiabetic drug to stimulate AMPK and inhibit mammalian target of rapamycin, (mTOR); 5) propranolol, a beta-blocker to block beta-adrenergic signaling; 6) agomelatine, a melatonergic antidepressant to stimulate M1 and M2 melatonergic receptors; and 7) ribavirin, an antiviral drug to prevent eIF4E phosphorylation. All these block the signaling pathways - RANK, TGF-beta, mTOR, beta-adrenergic receptors, and phosphorylated eIF4E - that have been shown to trigger EMT and enhance breast cancer growth and so are worthwhile targets to inhibit. Agonism at MT1 and MT2 melatonergic receptors has been shown to inhibit both breast cancer EMT and growth. This ensemble was designed to be safe and augment capecitabine efficacy. Given the expected outcome of metastatic breast cancer as it stands today, ABC7 warrants a cautious trial.