MNK/eIF4E inhibition overcomes anlotinib resistance in non-small cell lung cancer

RAF1 promotes anlotinib resistance in non-small cell lung cancer by inhibiting apoptosis

BACKGROUND

Anlotinib is an effective treatment for advanced non-small cell lung cancer (NSCLC), but resistance to it often develops during therapy. RAF1, a serine/threonine kinase involved in cancer progression, has limited research in NSCLC, particularly regarding anlotinib resistance.

METHODS

Analysis of RAF1 expression in NSCLC and its relationship with targeted therapy resistance and apoptosis through bioinformatics methods. Immunohistochemistry (IHC) was employed to evaluate the relationship between RAF1 expression and anlotinib resistance in NSCLC tissues. Anlotinib-resistant PC9 (PC9/AR) cells were constructed in vitro, and cell viability and apoptosis were assessed using the cell counting kit-8 (CCK-8) assay and flow cytometry. Quantitative real-time PCR (qRT-PCR) was carried out to evaluate RAF1 gene expression levels, and western blot (WB) analysis was conducted to determine the expression of RAF1, Bcl-2-associated X protein (Bax) and B-cell lymphoma 2 (Bcl-2).

RESULTS

Bioinformatics analysis showed that RAF1 was lowly expressed in lung cancer tissues in TCGA and GEPIA databases. Further pathway analysis indicated that RAF1 expression was positively correlated with targeted therapy resistance and negatively correlated with the expression of the anti-apoptotic protein Bcl-2. Immunohistochemical analysis showed that high RAF1 expression in NSCLC tissues was related to anlotinib resistance (P < 0.05). In vitro experiments demonstrated that RAF1 contributed to anlotinib resistance in NSCLC cells. Overexpression of RAF1 increased cell viability and decreased apoptosis in PC9 and PC9/AR cells, while knockdown of RAF1 had the opposite effects.

CONCLUSION

RAF1 mediates anlotinib resistance in NSCLC cells by regulating apoptosis and may serve as a predictive marker for anlotinib resistance in advanced lung cancer patients.

Capivasertib augments chemotherapy via Akt inhibition in preclinical small cell lung cancer models

BACKGROUND

Small cell lung cancer (SCLC) is a highly aggressive type of lung cancer for which platinum-based chemotherapy is the standard of care. Despite an initial response to this therapy, patients eventually develop resistance to the chemotherapy.

OBJECTIVES

To investigate the potential of capivasertib, an approved drug for advanced breast cancer, to enhance the efficacy of cisplatin in preclinical SCLC models and explore the underlying mechanisms.

METHODS

SCLC cell lines were treated with capivasertib and cisplatin, alone or in combination, to assess cell viability, proliferation, colony formation, and apoptosis. Next, capivasertib's effects, alone and combined with cisplatin, were evaluated in an SCLC mouse model. Mechanistic studies focused on Akt and MYC signaling, with constitutively active Akt overexpression used to assess its role.

RESULTS

Capivasertib is active against a panel of SCLC cell lines regardless of cellular origin and genetic profiling with IC50 at a clinically achievable range. Particularly, capivasertib inhibits proliferation and anchorage-independent colony formation and induces apoptosis in SCLC cells. It significantly augments cisplatin's inhibitory effects in all tested cell lines. Importantly, capivasertib at a non-toxic dose is effective in delaying SCLC growth in mice and its combination with cisplatin achieves nearly complete tumor growth inhibition. Mechanistic studies confirm that capivasertib inhibits Akt and MYC signaling, and furthermore, that overexpression of constitutively active Akt reversed anti-SCLC activity of capivasertib.

CONCLUSION

Our work is the first to reveal that Akt inhibition can augment chemotherapy in SCLC, and capivasertib is a useful addition to the treatment armamentarium for SCLC.

MicroRNA-150-3p enhances the antitumour effects of CGP57380 and is associated with a favourable prognosis in non-small cell lung cancer

MicroRNA (miRNA) dysregulation has been identified in several carcinomas, including non-small cell lung cancer (NSCLC), and is known to play a role in the development and progression of this disease. We initially conducted a miRNA microarray analysis, which revealed that the MNK inhibitor CGP57380 increased the expression of miR-150-3p. A similar analysis was performed using data from The Cancer Genome Atlas (TCGA). Cell proliferation, colony formation and migration assays were validated in A549 and H157 cells treated with miR-150-3p mimics. Quantitative polymerase chain reaction (qPCR) was then used to detect potential target genes. We observed significant downregulation of miR-150-3p in NSCLC samples compared with normal samples (P = 0.035). High miR-150-3p expression was associated with longer overall survival (P = 0.005), as determined via a tissue microarray (TMA). These results were validated in the TCGA and revealed that miR-150-3p was expressed at low levels in NSCLC tissues (P < 0.0001) and that patients with high miR-150-3p expression had a better prognosis (P = 0.042). Moreover, the combination of miR-150-3p and CGP57380 exerted a synergistic inhibitory effect on colony formation, growth, and migration and induced apoptosis in NSCLC cell lines. We investigated the potential targets of miR-150-3p and successfully validated six potential target genes through qPCR analysis. High miR-150-3p expression may enhance the response to immunotherapy, cisplatin and gemcitabine. In summary, this study underscores the promising therapeutic implications of combining miR-150-3p and CGP57380 for NSCLC treatment. Additionally, this study provides valuable insights into the molecular mechanisms underlying the effects of this treatment.

METTL3 inhibitor STM2457 impairs tumor progression and enhances sensitivity to anlotinib in OSCC

OBJECTIVES

To investigate the inhibitory effects of STM2457, which is a novel METTL3 (m6A writer) inhibitor, both as a monotherapy and in combination with anlotinib, in the treatment of oral squamous cell carcinoma (OSCC) both in vitro and in vivo.

MATERIALS AND METHODS

The efficacy of STM2457 or STM2457 plus anlotinib was evaluated using two OSCC cell lines by CCK8, transwell, colony formation, would-healing, sphere formation, cell cycle, apoptosis assays, and nude mice tumor xenograft techniques. The molecular mechanism study was carried out by western blotting, qRT-PCR, MeRIP-qPCR, immunofluorescence, and immunohistochemistry.

RESULTS

STM2457 combined with anlotinib enhanced inhibition of cellular survival/proliferation and promotion of apoptosis in vitro. Moreover, this combinatorial approach exerted a notable reduction in stemness properties and EMT (epithelial-mesenchymal transition) features of OSCC cells. Remarkably, in vivo studies validated the efficacy of the combination treatment. Mechanistically, our investigations revealed that the combined action of STM2457 and anlotinib exerted downregulatory effects on EGFR (epidermal growth factor receptor) expression in OSCC cells.

CONCLUSIONS

The combination of STM2457 and anlotinib targeting EGFR exerted a multiple anti-tumor effect. In near future, anlotinib combined with STM2457 may provide a novel insight for the treatment of OSCC.

Selective and effective suppression of pancreatic cancer through MNK inhibition

Objective: The study aimed to explore the role of the Wnt/β-catenin signaling pathway in pancreatic cancer progression and chemoresistance, with a focus on identifying specific factors that distinguish between normal and tumor cells, thereby offering potential therapeutic targets.

Materials and Methods: We analyzed levels of total and phosphorylated eukaryotic translation initiation factor 4E (eIF4E) and β-catenin in pancreatic cancer and normal pancreatic tissues. Functional assays were used to assess the impact of eIF4E phosphorylation on β-catenin signaling, cell proliferation, and chemoresistance, with MNK kinase involvement determined through gene depletion studies. The MNK kinase inhibitor eFT508 was evaluated for its effects on eIF4E phosphorylation, β-catenin activation, and cell viability in both in vitro and in vivo models of pancreatic cancer.

Results: Both total and phosphorylated eIF4E, along with β-catenin, were significantly elevated in pancreatic cancer tissues compared to normal tissues. Phosphorylation of eIF4E at serine 209 was shown to activate β-catenin signaling, enhance cell proliferation, and contribute to chemoresistance in pancreatic cancer. Importantly, these effects were dependent on MNK kinase activity. Depletion of eIF4E reduced cell viability in both pancreatic cancer and normal cells, while depletion of MNK selectively decreased viability in pancreatic cancer cells. Treatment with eFT508 effectively inhibited eIF4E phosphorylation, suppressed β-catenin activation, and reduced pancreatic cancer cell growth and survival in vitro and in vivo, with minimal impact on normal cells.

Conclusions: The MNK-eIF4E-β-catenin axis plays a critical role in pancreatic cancer progression and chemoresistance, distinguishing pancreatic cancer cells from normal cells. Targeting MNK kinases with inhibitors like eFT508 presents a promising therapeutic strategy for pancreatic cancer, with potential for selective efficacy and reduced toxicity.

Dual targeting of Mcl-1 and Bcl-2 to overcome chemoresistance in cervical and colon cancer

After an initial positive response to chemotherapy, cancer patients often become resistant and experience relapse. Our previous research identified eukaryotic translation initiation factor 4E (eIF4E) as a crucial target to overcome chemoresistance. In this study, we delved further into the role and therapeutic potential of myeloid cell leukemia 1 (Mcl-1), an eIF4E-mediated target, in chemoresistance. We showed that the levels of phosphor and total eIF4E, as well as Mcl-1, were elevated in chemoresistant cervical but not colon cancer cells. Mcl-1 inhibitor S64315 decreased Mcl-1 levels in chemoresistant cancer cells, regardless of Mcl-1 upregulation, decreased viability in chemoresistant cancer cells and acted synergistically with chemotherapy drugs. The combined inhibition of Mcl-1 and B-cell lymphoma 2 (Bcl-2), employing both genetic and pharmacological approaches, led to a markedly more substantial decrease in viability compared with the inhibition of either target individually. The combination of S64315 and Bcl-2 inhibitors reduced tumor growth in chemoresistant cervical and colon cancer models without causing general toxicity in mice. This combination also prolonged overall survival compared with using S64315 or venetoclax alone. Our research highlights the therapeutic potential of inhibiting Mcl-1 and Bcl-2 simultaneously in chemoresistant cancers and provides a rationale for initiating clinical trials to investigate the combination of S64315 and venetoclax for the treatment of advanced colon and cervical cancer.

Inhibition of eukaryotic initiation factor 4E by tomivosertib suppresses angiogenesis, growth, and survival of glioblastoma and enhances chemotherapy's efficacy

Glioblastoma is characterized by extensive vascularization and is highly resistant to current therapy. Identification of drugs that target tumor directly and angiogenesis processes present an effective therapeutic strategy for glioblastoma. Mnk kinase is required for the activation of eukaryotic initiation factor 4E (eIF4E), which mediates translation of oncogenic proteins. We investigated the effects of tomivosertib, a novel MAPK-interacting kinase (MNK) inhibitor, on glioblastoma angiogenesis, growth, and survival. We found that tomivosertib inhibited growth and induced caspase-dependent apoptosis in various glioblastoma cell lines. Tomivosertib disrupted glioblastoma endothelial cell capillary network formation, growth, and survival. Mechanistically, tomivosertib acted on glioblastoma via suppressing MNK-dependent eIF4E phosphorylation and activation in tumor and endothelial cells. We further found that temozolomide activated eIF4E and this was reversed by tomivosertib. Using glioblastoma xenograft mouse model, we demonstrated that temozolomide and tomivosertib combination had higher efficacy than tomivosertib alone. Of note, tomivosertib inhibited glioblastoma angiogenesis and decreased p-eIF4E level in mice. We finally showed that p-eIF4E activation was a common molecular feature in glioblastoma patients. Our pre-clinical findings suggest that tomivosertib is a useful addition to the treatment armamentarium for glioblastoma and that targeting MNK-eIF4E pathway represents a therapeutic strategy to overcome glioblastoma chemoresistance.