Suppression of EGFR/PKC-δ/NF-κB Signaling Associated With Imipramine-Inhibited Progression of Non-Small Cell Lung Cancer

Mechanistic insights of lenvatinib: enhancing cisplatin sensitivity, inducing apoptosis, and suppressing metastasis in bladder cancer cells through EGFR/ERK/P38/NF-κB signaling inactivation

BACKGROUND

The persistent activation of the epidermal growth factor receptor (EGFR) leads to the activation of downstream oncogenic kinases and transcription factors, resulting in tumor progression and an increased resistance to cisplatin in bladder cancer (BC) cells. Lenvatinib, an oral multikinase inhibitor, has the potential to offer therapeutic benefits as an adjuvant treatment for BC patients. The investigation into its application in bladder cancer treatment is a valuable endeavor. The primary goal of this study is to confirm the effectiveness and mechanism of lenvatinib in inhibiting the progression of BC and enhancing the anticancer efficacy of cisplatin.

MATERIALS

Three BC cell lines, namely, TSGH-8301, T24, and MB49, along with an MB49-bearing animal model, were utilized in this study.

RESULTS

In vitro experiments utilizing MTT assays demonstrated that lenvatinib sensitized BC cells to cisplatin, exhibiting a synergistic effect. Flow cytometry indicated apoptotic events and signaling, presenting that lenvatinib effectively induced apoptosis and triggered extrinsic/intrinsic apoptotic pathways. In vivo studies using a mouse model of BC confirmed the antitumor efficacy of lenvatinib, demonstrating significant tumor growth suppression without inducing toxicity in normal tissues. Western blotting analysis and immunohistochemistry stain revealed EGF-phosphorylated EGFR and EGFR-mediated ERK/P38/NF-κB signaling were suppressed by treatment with lenvatinib. In addition, lenvatinib also suppressed anti-apoptotic (MCL1, c-FLIP, and XIAP) and metastasis-related factors (Twist, Snail-1, ZEB-1, ZEB-2, and MMP9) and promoted epithelial markers (E-cadherin) while reducing mesenchymal markers (N-cadherin).

CONCLUSION

In conclusion, the induction of apoptosis and the inhibition of EGFR/ERK/P38/NF-κB signaling are correlated with lenvatinib's ability to hinder tumor progression and enhance the cytotoxic effects of cisplatin in bladder cancer. These findings underscore the potential of lenvatinib as a therapeutic option for bladder cancer, either as a standalone treatment or in combination with cisplatin.

Innovative role of the antidepressant imipramine in esophageal squamous cell carcinoma treatment: Promoting apoptosis and protective autophagy

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is among the most prevalent malignant tumors; it is associated with dismal prognosis, and effective therapeutic agents are lacking. Depression is prevalent concern among cancer patients and is linked to diminished quality of life, poor adherence to treatment, heightened risk of suicide, and poorer prognosis. Imipramine (IM) is a tricyclic antidepressant with anti-inflammatory activity. Recent reports have indicated antitumor effects of IM in various cancers, although its role in ESCC remains unclear.

METHODS

The depression status of patients with ESCC was graded with the Patient Health Questionnaire-9, and the effects of antidepressants (moclobemide, milnacipran, venlafaxine, escitalopram, amitriptyline, trazodone, fluvoxamine, and IM) on cell viability were evaluated through CCK-8 assays. The effects of IM on cell proliferation were evaluated through clone formation assays, whereas Transwell assays were used to assess effects on ESCC cell migration and invasion. IM-induced apoptosis was confirmed with annexin V-FITC/Caspase-3 assays, and immunofluorescence staining was used to investigate the formation of IM-induced autophagosomes. Furthermore, western blotting analysis was conducted to determine the expression levels of apoptosis- and autophagy-related proteins. RNA sequencing (RNA-seq) was used to examine signaling pathway changes. Finally, we investigated the influence of IM on tumor progression in vivo in a xenograft model.

RESULTS

The PHQ-9 scores of patients with ESCC were higher than those of healthy controls and positively correlated with the TNM stage of ESCC. Among the antidepressants examined in our study, IM demonstrated the most potent inhibitory effect on ESCC cell viability, and effectively suppressed the proliferation, migration, and invasion of ESCC cells. Additionally, IM treatment induced apoptosis and autophagy in ESCC cells. Furthermore, blocking autophagy with chloroquine (CQ) intensified IM-induced apoptosis, thereby suggesting a protective role of cellular autophagy against apoptosis. RNA-seq results indicated that the Hippo pathway was associated with IM treatment. Upregulation of YAP reversed the apoptosis and autophagy triggered by IM, and targeting YAP intensified this effect. Finally, in animal experiments, IM hindered the growth of ESCC cells and promoted apoptosis and autophagy in tumors while causing minimal toxicity.

CONCLUSION

Our findings provide the first reported evidence that IM triggers apoptosis and protective autophagy in ESCC cells via the Hippo signaling pathway, thus suggesting that IM may offer a promising therapeutic approach for patients with ESCC and depression.

PKC-δ Promotes IL-1β-Induced Apoptosis of Rat Chondrocytes and Via Activating JNK and P38 MAPK Pathways

OBJECTIVE

Protein kinase C-delta (PKC-δ) is involved in apoptosis. This study aimed to establish whether PKC-δ can further promote IL-1β-induced chondrocyte apoptosis by mediating the phosphorylation of the JNK and p38 mitogen-activated protein kinase (MAPK) signaling pathways In osteoarthritis (OA).

METHODS

We employed chondrocyte staining to determine the extent of cartilage degeneration. PKC-δ and p38 signal expressions were used in the immunohistochemical (IHC) test and apoptosis was assayed at the TUNEL test in human osteoarthritic and controls. We stimulated rat cartilage cells using IL-1β (10 ng/ml)/rottlerin (10 μM) or lentivirus. To determine the apoptosis rate, we employed flow cytometry. The mRNA of both BCL2-related X (BAX) and cysteine aspartate protease 3 (caspase-3) could be measured via qRT-PCR. Western blot measured the protein levels of BAX, caspase-3, PKC-δ, p-JNK/JNK and p-p38/p38.

RESULTS

The positive rate of PKC-δ and the apoptotic rate of chondrocytes in OA were higher than controls. The manifestation of PKC-δ was positively related to the degree of cartilage degeneration, p38 protein expression, and apoptosis rate. IL-1β exposure upregulated PKC-δ expression in chondrocytes in a dose-dependent manner. Decreasing PKC-δ expression and its phosphorylation in OA can inhibit MAPK signaling pathway activation (phosphorylation) by downregulating JNK and p38 protein phosphorylation and expression. This inhibition decreases caspase-3 and BAX levels, consequently lowering the apoptosis rate in chondrocytes.

CONCLUSION

PKC-δ activation by IL-1β in OA promotes chondrocyte apoptosis via activation of the JNK and p38 MAPK signal pathways, thereby promoting the OA progression.

A multifunctional PEGylated liposomal-encapsulated sunitinib enhancing autophagy, immunomodulation, and safety in renal cell carcinoma

BACKGROUND

Sunitinib is a multikinase inhibitor used to treat patients with advanced renal cell carcinoma (RCC). However, sunitinib toxicity makes it a double-edged sword. Potent immune modulation by sunitinib extends to nuclear interactions. To address these issues, there is an urgent need for delivery vectors suitable for sunitinib treatment.

METHODS

We developed PEGylated liposomes as delivery vectors to precisely target sunitinib (lipo-sunitinib) to RCC tumors. Further investigations, including RNA sequencing (RNA-seq), were performed to evaluate transcriptomic changes in these pathways. DiI/DiR-labeled lipo-sunitinib was used for the biodistribution analysis. Flow cytometry and immunofluorescence (IF) were used to examine immune modulation in orthotopic RCC models.

RESULTS

The evaluation of results indicated that lipo-sunitinib precisely targeted the tumor site to induce autophagy and was readily taken up by RCC tumor cells. In addition, transcriptomic assays revealed that following lipo-sunitinib treatment, autophagy, antigen presentation, cytokine, and chemokine production pathways were upregulated, whereas the epithelial-mesenchymal transition (EMT) pathway was downregulated. In vivo data provided evidence supporting the inhibitory effect of lipo-sunitinib on RCC tumor progression and metastasis. Flow cytometry further demonstrated that liposunitinib increased the infiltration of effector T cells (Teffs) and conventional type 1 dendritic cells (cDC1s) into the tumor. Furthermore, systemic immune organs such as the tumor-draining lymph nodes, spleen, and bone marrow exhibited upregulated anticancer immunity following lipo-sunitinib treatment.

CONCLUSION

Our findings demonstrated that lipo-sunitinib is distributed at the RCC tumor site, concurrently inducing potent autophagy, elevating antigen presentation, activating cytokine and chemokine production pathways, and downregulating EMT in RCC cells. This comprehensive approach significantly enhanced tumor inhibition and promoted anticancer immune modulation.

Solanine Inhibits Proliferation and Angiogenesis and Induces Apoptosis through Modulation of EGFR Signaling in KB-ChR-8-5 Multidrug-Resistant Oral Cancer Cells

Background: The most important factors contributing to multi-drug resistance in oral cancer include overexpression of the EGFR protein and the downstream malignancy regulators that are associated with it. This study investigates the impact of solanine on inflammation, proliferation, and angiogenesis inhibition in multidrug-resistant oral cancer KB-Chr-8-5 cells through inhibition of the EGFR/PI3K/Akt/NF-κB signaling pathway. Methods: Cell viability was assessed using an MTT assay to evaluate cytotoxic effects. Production of reactive oxygen species (ROS), mitochondrial membrane potential (ΔΨM), and AO/EtBr staining were analyzed to assess apoptosis and mitochondrial dysfunction. Western blotting was employed to examine protein expression related to angiogenesis, apoptosis, and signaling pathways. Experiments were conducted in triplicate. Results: Solanine treatment at concentrations of 10, 20, and 30 μM significantly increased ROS production, which is indicative of its antioxidant properties. This increase was associated with decreased mitochondrial membrane potential (ΔΨM) with p < 0.05, suggesting mitochondrial dysfunction. Inhibition of EGFR led to reduced activity of PI3K, Akt, and NF-κB, resulting in decreased expression of iNOS, IL-6, Cyclin D1, PCNA, VEGF, Mcl-1, and HIF-1α and increased levels of the apoptotic proteins Bax, caspase-9, and caspase-3. These changes collectively inhibited the growth of multidrug-resistant (MDR) cancer cells. Conclusions: Solanine acts as a potent disruptor of cellular processes by inhibiting the EGFR-mediated PI3K/Akt/NF-κB signaling pathway. These results suggest that solanine holds promise as a potential preventive or therapeutic agent against multidrug-resistant cancers.

Quetiapine Significantly Improves the Effectiveness of Radiotherapy in Combating Hepatocellular Carcinoma Progression in a Hep3B Xenograft Mouse Model

BACKGROUND/AIM

In hepatocellular carcinoma (HCC) treatment, radiotherapy (RT) stands as a pivotal approach, yet the emergence of radioresistance poses a formidable challenge. This study aimed to explore the potential synergy between quetiapine and RT for HCC treatment.

MATERIALS AND METHODS

A Hep3B xenograft mouse model was used, the investigation tracked tumor progression, safety parameters, and molecular mechanisms.

RESULTS

The findings revealed a synergistic anti-HCC effect when quetiapine was coupled with RT that prolonged tumor growth time and a significantly higher growth inhibition rate compared to the control group. Safety assessments indicated minimal pathological changes, suggesting potential of quetiapine in mitigating RT-induced alterations in liver and kidney functions. Mechanistically, the combination suppressed metastasis and angiogenesis-related proteins, while triggering the activation of apoptosis-related proteins via targeting Epidermal growth factor receptor (EGFR)-mediated signaling.

CONCLUSION

The potential of the quetiapine and RT combination is emphasized, offering enhanced anti-HCC efficacy, a safety profile, and positioning quetiapine as a radiosensitizer for HCC treatment.

Unveiling nature's potential weapon: Magnolol's role in combating bladder cancer by upregulating the miR-124 and inactivating PKC-δ/ERK axis

BACKGROUND

Bladder cancer (BC) is a challenging disease to manage. Researchers have been investigating the potential of magnolol, a compound derived from Magnolia officinalis, as an anti-cancer agent. However, the exact regulatory mechanism of magnolol and its impact on the NF-κB signaling pathway in BC remain unclear.

MATERIALS

To comprehensively evaluate its therapeutic potential, the researchers conducted a series of experiments using BC cell lines (TSGH8301, T24, and MB49) and in vivo animal models.

RESULTS

The results of the study demonstrated that magnolol exhibits cytotoxic effects on BC cells by activating both the extrinsic and intrinsic apoptosis signaling pathways. Additionally, the expression of anti-apoptotic genes was downregulated by magnolol treatment. The researchers also uncovered the regulatory role of PKCδ/ERK and miR-124-3p in the NF-κB pathway, which may be influenced by magnolol. Treatment with magnolol led to the inactivation of PKCδ/ERK and an increase in miR-124-3p expression, effectively inhibiting NF-κB-mediated progression of BC. Importantly, the administration of magnolol did not result in significant toxicity in normal tissues, highlighting its potential as a safe adjunctive therapy with minimal adverse effects.

CONCLUSION

These findings position magnolol as a promising therapeutic agent for the treatment of BC. By activating apoptosis signaling pathways and inhibiting NF-κB pathway through the upregulation of miR-124-3p and downregulation of PKCδ/ERK activation, magnolol holds promise for suppressing tumor progression and improving patient outcomes in BC. Further research and clinical trials are warranted to explore the full potential of magnolol in the future.

The Anti-atherosclerosis Mechanism of Ziziphora clinopodioides Lam. Based On Network Pharmacology

We investigated the mechanisms underlying the effects of Ziziphora clinopodioides Lam. (ZCL) on atherosclerosis (AS) using network pharmacology and in vitro validation.We collected the active components of ZCL and predicted their targets in AS. We constructed the protein-protein interaction, compound-target, and target-compound-pathway networks, and performed GO and KEGG analyses. Molecular docking of the active components and key targets was constructed with Autodock and Pymol software. Validation was performed with qRT-PCR, ELISA, and Western blot.We obtained 80 components of ZCL. The network analysis identified that 14 components and 37 genes were involved in AS. Then, 10 key nodes in the PPI network were identified as the key targets of ZCL because of their importance in network topology. The binding energy of 8 components (Cynaroside, α-Spinasterol, Linarin, Kaempferide, Acacetin, Genkwanin, Chrysin, and Apiin) to 4 targets (MMP9, TP53, AKT1, SRC) was strong and <-1 kJ/mol. In addition, 13 of the 14 components were flavonoids and thus total flavonoids of Ziziphora clinopodioides Lam. (ZCF) were used for in vitro validation. We found that ZCF reduced eNOS, P22phox, gp91phox, and PCSK9 at mRNA and protein levels, as well as the levels of IL-1β, TNF-α, and IL-6 proteins in vitro (P < 0.05).We successfully predicted the active components, targets, and mechanisms of ZCL in treating AS using network pharmacology. We confirmed that ZCF may play a role in AS by modulating oxidative stress, lipid metabolism, and inflammatory response via Cynaroside, Linarin, Kaempferide, Acacetin, Genkwanin, Chrysin, and Apiin.

Psychological distress influences lung cancer: Advances and perspectives on the immune system and immunotherapy

Lung cancer has the highest incidence rate and mortality worldwide. Moreover, multiple factors may cause heterogeneity in the efficacy of immunotherapy for lung cancer, and preclinical studies have gradually uncovered the promotive effects of psychological distress (PD) on tumor hallmarks. Therefore, treatment targeted at PD may be a vital factor in adjusting and improving immunotherapy for lung cancer. Here, by focusing on the central nervous system, as well as stress-related crucial neurotransmitters and hormones, we highlight the effects of PD on the lung immune system, the lung tumor microenvironment (TME) and immunotherapy, which brings a practicable means and psychosocial perspective to lung cancer treatment.

Fluoxetine inactivates STAT3/NF-κB signaling and promotes sensitivity to cisplatin in bladder cancer

Bladder cancer is known as one of the top ten most common cancer types worldwide and can be majorly divided into muscles invasive bladder cancer (MIBC) and non-muscles invasive type (NMIBC). However, the prognosis of BC remains poor under standard treatment including radical cystectomy or concurrent chemoradiotherapy. Numerous studies have reported that the prognosis of BC is associated with the activation of signal transducer and activator of transcription (STAT3) and nuclear factor kappa-B (NF-κB). Fluoxetine, a well-known anti-depressant, has been reported to against various type of cancers. However, it is unclear whether fluoxetine has the capacity to inhibit BC progression by targeting STAT3 and NF-κB-mediated signaling. Here, we used cell viability, apoptosis assay, wound healing assay, invasion/migration assay, Western blotting assay, immunofluorescence staining, as well as animal experiments, to elucidate the efficacy of fluoxetine on in vitro and in vivo BC models. We found that fluoxetine may induce cytotoxicity and intrinsic/extrinsic apoptosis in BC and enhance the potential of cisplatin. Fluoxetine promoted both caspase-dependent and caspase-independent apoptosis signaling by activating caspase-3, 8, 9, apoptosis-inducing factor (AIF), and EndG. Furthermore, fluoxetine suppressed invasion and migration ability and the expression of metastasis-associated genes. Fluoxetine was also found to inactivate the phosphorylation of STAT3 (Tyr705) and NF-κB (Ser536) and suppress the nuclear translocation of NF-κB. In MB49-bearing mice, fluoxetine effectively delayed the progression of BC without inducing general toxicity. In summary, the induction of apoptosis and the inhibition of invasion triggered by fluoxetine are associated with the inactivation of STAT3 and NF-κB.

Inactivation of EGFR/ERK/NF-κB signalling associates with radiosensitizing effect of 18β-glycyrrhetinic acid on progression of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is recognized as the fifth most common cancer and the third most common cause of death in Asian population. Studies reported that HCC is relatively insensitive to radiotherapy (RT); thus, considering how to sensitize HCC to RT is worth to be elucidated. Epidermal growth factor receptor (EGFR)-mediated signalling transduction plays the important role in regulating treatment efficacy of HCC. An active compound, 18beta-glycyrrhetinic acid (18β-GA), has been reported to own anti-tumour effect. However, whether 18β-GA possess RT sensitization ability in HCC remains unclear. Here, we used RNA data from TCGA-LIHC (Liver hepatocellular carcinoma) to identify the role between EGFR/ERK/nuclear factor kappa B (NF-κB) signalling and RT by radiosensitivity index (RSI) analysis. We suggested that patients with activated NF-κB signalling may show resistance to RT treatment, whereas combining 18β-GA may reinforce RT efficacy in a Hep3B-bearing animal model. 18β-GA combined with RT showed superior tumour inhibition capacity as compared to monotherapy and even reached similar efficacy as erlotinib combined with RT. Treatment promotion of RT by 18β-GA in HCC is not only through diminishing RT-induced EGFR/ERK/NF-κB signalling but also promoting RT-induced apoptosis pathways. 18β-GA may act as radiosensitizer through inactivating EGFR-mediated HCC progression and inducing caspase-dependent apoptosis signalling.

Amentoflavone induces caspase-dependent/-independent apoptosis and dysregulates cyclin-dependent kinase-mediated cell cycle in colorectal cancer in vitro and in vivo

Colorectal cancer (CRC) is recognized as the third most common malignancy and the second most deadly in highly developed countries. Although the treatment of CRC has improved in the past decade, the mortality rate of CRC is still increasing. Amentoflavone, one of the flavonoids detected in medical plants, is reported to possess potential anticancer properties in various cancers. However, its role in CRC has not been studied. This study aimed to investigate the role and underlying mechanism of amentoflavone on CRC in vitro and in vivo. We identified the cytotoxicity, apoptosis effect, cell cycle alteration, DNA damage induction and tumor progression inhibition of amentoflavone in HT-29 model by using MTT assay, flow cytometry, immunofluorescence (IF) staining, Western blotting and animal experiments. Amentoflavone induced cytotoxicity is caused by triggering G1 arrest, DNA damage and apoptosis in HT-29 cells. The expression of cyclin D1, CDK4 and CDK6 was decreased by amentoflavone; in contrast, the phosphorylation of ATM and CHK2 and the expression of p21 and p27 were increased. The apoptosis induction of amentoflavone in CRC is not only caspase-dependent but also increases EndoG and AIF nuclear translocation in a caspase-independent manner. Importantly, the apoptosis induction of amentoflavone is not affected by the activity of p53 in CRC. Amentoflavone suppressed the progression of CRC by initiating G1 arrest and ATM/CHK2-mediated DNA damage-responsive, caspase-dependent/independent apoptotic effects. We uncovered a novel tumor-inhibitory role of amentoflavone in CRC that is not associated with p53 activity, which may serve as a potential treatment for CRC.

Repurposing Antidepressants and Phenothiazine Antipsychotics as Efflux Pump Inhibitors in Cancer and Infectious Diseases

Multidrug resistance (MDR) is a major obstacle in the therapy of infectious diseases and cancer. One of the major mechanisms of MDR is the overexpression of efflux pumps (EPs) that are responsible for extruding antimicrobial and anticancer agents. EPs have additional roles of detoxification that may aid the development of bacterial infection and the progression of cancer. Therefore, targeting EPs may be an attractive strategy to treat bacterial infections and cancer. The development and discovery of a new drug require a long timeline and may come with high development costs. A potential alternative to reduce the time and costs of drug development is to repurpose already existing drugs. Antidepressants and antipsychotic agents are widely used in clinical practice in the treatment of psychiatric disorders and some somatic diseases. Antidepressants and antipsychotics have demonstrated various beneficial activities that may be utilized in the treatment of infections and cancer. This review aims to provide a brief overview of antibacterial and anticancer effects of selective serotonin reuptake inhibitors (SSRIs), tricyclic antidepressants (TCAs) and phenothiazine antipsychotics, while focusing on EPs. However, it should be noted that the antimicrobial activity of a traditionally non-antibiotic drug may have clinical implications regarding dysbiosis and bacterial MDR.

Hyperforin Suppresses Oncogenic Kinases and Induces Apoptosis in Colorectal Cancer Cells

BACKGROUND/AIM

Signal transducer and activator of transcription 3 (STAT3), Janus Kinase 1 (JAK1), extracellular signal-regulated kinase (ERK), and protein kinase B (AKT) are essential for malignant transformation and progression in colorectal cancer (CRC) and can be considered as targets for therapeutic interventions. Hyperforin, an active constituent from Hypericum perforatum, has been reported to inhibit inflammation. However, whether hyperforin may suppress CRC progression via inactivation of JAK/STAT3, ERK or AKT signaling remains unclear.

MATERIALS AND METHODS

Human CRC cells were used to identify the treatment efficacy of hyperforin and its underlying mechanisms of action by MTT, flow cytometry, wound healing, and western blotting assays.

RESULTS

Hyperforin not only induced cytotoxicity, extrinsic/intrinsic apoptosis signaling, but also suppressed the invasion/migration ability of CRC. The phosphorylation of STAT3, JAK1, ERK and AKT was found to be decreased by hyperforin.

CONCLUSION

Hyperforin inactivates multiple oncogenic kinases and induces apoptosis signaling in CRC cells.

The application of antidepressant drugs in cancer treatment

Antidepressants refer to psychotropic drugs which are used to treat mental illness with prominent emotional depression symptoms. It was reported that antidepressants had associated with anti-carcinogenic function which was associated with various signaling pathways and changing of microenvironment. Its mechanism includes cell apoptosis, antiproliferative effects, mitochondria-mediated oxidative stress, DNA damaging, changing of immune response and inflammatory conditions, and acting by inhibiting multidrug resistance of cancer cells. Accumulated studies showed that antidepressants influenced the metabolic pathway of tumor cells. This review summarized recent developments with the impacts and mechanisms of 10 kinds of antidepressants in carcinostasis. Antidepressants are also used in combination therapy with typical anti-tumor drugs which shows a synergic effect in anti-tumor. By contrast, the promotion roles of antidepressants in increasing cancer recurrence risk, mortality, and morbidity are also included. Further clinical experiments and mechanism analyses needed to be achieved. A full understanding of the underlying mechanisms of antidepressants-mediated anticarcinogenic effects may provide new clues for cancer prevention and clinical treatment.

Tumor PKCδ instigates immune exclusion in EGFR-mutated non-small cell lung cancer

BACKGROUND

The recruitment of a sufficient number of immune cells to induce an inflamed tumor microenvironment (TME) is a prerequisite for effective response to cancer immunotherapy. The immunological phenotypes in the TME of EGFR-mutated lung cancer were characterized as non-inflamed, for which immunotherapy is largely ineffective.

METHODS

Global proteomic and phosphoproteomic data from lung cancer tissues were analyzed aiming to map proteins related to non-inflamed TME. The ex vivo and in vivo studies were carried out to evaluate the anti-tumor effect. Proteomics was applied to identify the potential target and signaling pathways. CRISPR-Cas9 was used to knock out target genes. The changes of immune cells were monitored by flow cytometry. The correlation between PKCδ and PD-L1 was verified by clinical samples.

RESULTS

We proposed that PKCδ, a gatekeeper of immune homeostasis with kinase activity, is responsible for the un-inflamed phenotype in EGFR-mutated lung tumors. It promotes tumor progression by stimulating extracellular matrix (ECM) and PD-L1 expression which leads to immune exclusion and assists cancer cell escape from T cell surveillance. Ablation of PKCδ enhances the intratumoral penetration of T cells and suppresses the growth of tumors. Furthermore, blocking PKCδ significantly sensitizes the tumor to immune checkpoint blockade (ICB) therapy (αPD-1) in vitro and in vivo model.

CONCLUSIONS

These findings revealed that PKCδ is a critical switch to induce inflamed tumors and consequently enhances the efficacy of ICB therapy in EGFR-mutated lung cancer. This opens a new avenue for applying immunotherapy against recalcitrant tumors.

Protein Kinase C (PKC) Isozymes as Diagnostic and Prognostic Biomarkers and Therapeutic Targets for Cancer

Protein kinase C (PKC) is a large family of calcium- and phospholipid-dependent serine/threonine kinases that consists of at least 11 isozymes. Based on their structural characteristics and mode of activation, the PKC family is classified into three subfamilies: conventional or classic (cPKCs; α, βI, βII, and γ), novel or non-classic (nPKCs; δ, ε, η, and θ), and atypical (aPKCs; ζ, ι, and λ) (PKCλ is the mouse homolog of PKCι) PKC isozymes. PKC isozymes play important roles in proliferation, differentiation, survival, migration, invasion, apoptosis, and anticancer drug resistance in cancer cells. Several studies have shown a positive relationship between PKC isozymes and poor disease-free survival, poor survival following anticancer drug treatment, and increased recurrence. Furthermore, a higher level of PKC activation has been reported in cancer tissues compared to that in normal tissues. These data suggest that PKC isozymes represent potential diagnostic and prognostic biomarkers and therapeutic targets for cancer. This review summarizes the current knowledge and discusses the potential of PKC isozymes as biomarkers in the diagnosis, prognosis, and treatment of cancers.

Dexamethasone attenuates dry eye-induced pyroptosis by regulating the KCNQ1OT1/miR-214 cascade

Dry eye disease (DED) is an inflammatory disorder of the ocular surface seriously affecting the quality of life of patients. Topical dexamethasone (Dex) administration protects the cornea from the hyperosmotic stress (HS) induced by tears. Pyroptosis participates in the activation of epithelial inflammation during DED. However, it remains unclear whether Dex attenuates the progression of DED through pyroptosis. In this study, we aimed to investigate the effect of Dex on DED using both cell and animal models and its underlying mechanism. The inflammatory factors contained in tears were detected using a cytokine assay. The pyroptosis in DED mice and human corneal epithelial cells (HCECs) treated with hyperosmotic medium under various treatments was evaluated by immunohistochemical assays (IHC) or western blotting (WB). RNA expression was manipulated with siRNA or agomir microRNAs and measured using a polymerase chain reaction. The scratch assay was used to assess the migration rate of HCECs. Remaining corneal defects were evaluated using fluorescein staining and photographed using a digital camera. Dex could suppress the release of inflammatory factors and notably attenuate pyroptosis, KCNQ1OT1 expression, and NF-κB activation induced by HS injury in vivo and in vitro. KCNQ1OT1 upregulation could activate pyroptosis by sponging miR-214. Furthermore, KCNQ1OT1 knockdown and miR-214 overexpression reversed the effect of HS, promoted the migration of HCECs, and accelerated corneal wound healing. Dex effectively suppressed HS-induced pyroptosis through the KCNQ1OT1/miR-214/caspase-1 signaling axis by inhibiting the NF-κB activation. Our results provide a novel understanding of the mechanism of Dex as an anti-inflammatory drug in DED.

Antitumoral Effects of Tricyclic Antidepressants: Beyond Neuropathic Pain Treatment

Simple Summary

Tricyclic antidepressants (TCAs) are old and known therapeutic agents whose good safety profile makes them good candidates for drug repurposing. As the relevance of nerves in cancer development and progression is being unveiled, attention now turns to the use of nerve-targeting drugs, such as TCAs, as an interesting approach to combat cancer. In this review, we discuss current evidence about the safety of TCAs, their application to treat neuropathic pain in cancer patients, and in vitro and in vivo demonstrations of the antitumoral effects of TCAs. Finally, the results of ongoing clinical trials and future directions are discussed.

Abstract

Growing evidence shows that nerves play an active role in cancer development and progression by altering crucial molecular pathways and cell functions. Conversely, the use of neurotropic drugs, such as tricyclic antidepressants (TCAs), may modulate these molecular signals with a therapeutic purpose based on a direct antitumoral effect and beyond the TCA use to treat neuropathic pain in oncology patients. In this review, we discuss the TCAs’ safety and their central effects against neuropathic pain in cancer, and the antitumoral effects of TCAs in in vitro and preclinical studies, as well as in the clinical setting. The current evidence points out that TCAs are safe and beneficial to treat neuropathic pain associated with cancer and chemotherapy, and they block different molecular pathways used by cancer cells from different locations for tumor growth and promotion. Likewise, ongoing clinical trials evaluating the antineoplastic effects of TCAs are discussed. TCAs are very biologically active compounds, and their repurposing as antitumoral drugs is a promising and straightforward approach to treat specific cancer subtypes and to further define their molecular targets, as well as an interesting starting point to design analogues with increased antitumoral activity.