Interplay of MKP-1 and Nrf2 drives tumor growth and drug resistance in non-small cell lung cancer

Acute COVID-19 and LongCOVID syndrome - molecular implications for therapeutic strategies - review

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has been recognized not only for its acute effects but also for its ability to cause LongCOVID Syndrome (LCS), a condition characterized by persistent symptoms affecting multiple organ systems. This review examines the molecular and immunological mechanisms underlying LCS, with a particular focus on autophagy inhibition, chronic inflammation, oxidative, nitrosative and calcium stress, viral persistence and autoimmunology. Potential pathophysiological mechanisms involved in LCS include (1) autoimmune activation, (2) latent viral persistence, where SARS-CoV-2 continues to influence host metabolism, (3) reactivation of latent pathogens such as Epstein-Barr virus (EBV) or cytomegalovirus (CMV), exacerbating immune and metabolic dysregulation, and (4) possible persistent metabolic and inflammatory dysregulation, where the body fails to restore post-infection homeostasis. The manipulation of cellular pathways by SARS-CoV-2 proteins is a critical aspect of the virus' ability to evade immune clearance and establish long-term dysfunction. Viral proteins such as NSP13, ORF3a and ORF8 have been shown to disrupt autophagy, thereby impairing viral clearance and promoting immune evasion. In addition, mitochondrial dysfunction, dysregulated calcium signaling, oxidative stress, chronic HIF-1α activation and Nrf2 inhibition create a self-sustaining inflammatory feedback loop that contributes to tissue damage and persistent symptoms. Therefore understanding the molecular basis of LCS is critical for the development of effective therapeutic strategies. Targeting autophagy and Nrf2 activation, glycolysis inhibition, and restoration calcium homeostasis may provide novel strategies to mitigate the long-term consequences of SARS-CoV-2 infection. Future research should focus on personalized therapeutic interventions based on the dominant molecular perturbations in individual patients.

Understanding chronic inflammation: couplings between cytokines, ROS, NO, Cai 2+, HIF-1α, Nrf2 and autophagy

Chronic inflammation is an important component of many diseases, including autoimmune diseases, intracellular infections, dysbiosis and degenerative diseases. An important element of this state is the mainly positive feedback between inflammatory cytokines, reactive oxygen species (ROS), nitric oxide (NO), increased intracellular calcium, hypoxia-inducible factor 1-alpha (HIF-1α) stabilisation and mitochondrial oxidative stress, which, under normal conditions, enhance the response against pathogens. Autophagy and the nuclear factor erythroid 2-related factor 2 (Nrf2)-mediated antioxidant response are mainly negatively coupled with the above-mentioned elements to maintain the defence response at a level appropriate to the severity of the infection. The current review is the first attempt to build a multidimensional model of cellular self-regulation of chronic inflammation. It describes the feedbacks involved in the inflammatory response and explains the possible pathways by which inflammation becomes chronic. The multiplicity of positive feedbacks suggests that symptomatic treatment of chronic inflammation should focus on inhibiting multiple positive feedbacks to effectively suppress all dysregulated elements including inflammation, oxidative stress, calcium stress, mito-stress and other metabolic disturbances.

DUSP1 Promotes Osimertinib Drug-Tolerant Persistence by Inhibiting MAPK/ERK Signaling in Non-small Cell Lung Cancer

EGFR tyrosine kinase inhibitors (EGFR-TKIs) are the first-line treatment for EGFR-mutant non-small cell lung cancer (NSCLC) patients, which remarkably improve the clinical outcomes. However, drug resistance has greatly impaired the efficacy of EGFR-TKIs and contributes to cancer treatment failure. DUSP1, a negative regulator of MAPK signaling pathway, was discovered to mediate drug resistance in multiple types of cancers. Our study aimed to explore the role of DUSP1 in NSCLC cell resistance to osimertinib, a third-generation EGFR-TKI. Human NSCLC cell lines PC-9 and HCC827 were exposed to increasing concentrations of osimertinib for over 6 months to generate osimertinib resistant cells (PC-9-OR and HCC827-OR). The viabilities of osimertinib-resistant and parental sensitive NSCLC cells in response to osimertinib stimulation were detected by MTS assay and the IC50 values for osimertinib were obtained. The differentially expressed genes in osimertinib-resistant and sensitive NSCLC cells were identified by analyzing the GEO dataset GSE106765 using bioinformatic tools. DUSP1 expression was knocked down by using the short hairpin RNAs (shRNAs). Then, the effects of DUSP1 silencing on osimertinib-resistant and sensitive NSCLC cell resistance to osimertinib, viability, proliferation and apoptosis were assessed through loss-of-function experiments. The expression of key molecules (JNK, ERK, and p38 MAPK) in the MAPK signaling pathway was detected through western blotting analysis. DUSP1 was overexpressed in osimertinib-resistant NSCLC cells versus parental sensitive cells. DUSP1 silencing attenuated the resistance of NSCLC cells to osimertinib. DUSP1 silencing markedly inhibited osimertinib-resistant and sensitive NSCLC cell proliferation but enhanced cell apoptosis. Mechanically, DUSP1 knockdown increased phosphorylated-JNK, ERK, and p38 MAPK levels in NSCLC cells. Treatment with SB203580, the p38 MAPK inhibitor, reversed the effects of DUSP1 silencing on osimertinib-resistant NSCLC cell resistance to osimertinib, cell proliferation and apoptosis. DUSP1 downregulation restores the sensitivity of NSCLC cells to osimertinib via activating the MAPK signaling pathway.

MAPK phosphatase 1 inhibition of p38α within lung myofibroblasts is essential for spontaneous fibrosis resolution

Fibrosis following tissue injury is distinguished from normal repair by the accumulation of pathogenic and apoptosis-resistant myofibroblasts (MFs), which arise primarily by differentiation from resident fibroblasts. Endogenous molecular brakes that promote MF dedifferentiation and clearance during spontaneous resolution of experimental lung fibrosis may provide insights that could inform and improve the treatment of progressive pulmonary fibrosis in patients. MAPK phosphatase 1 (MKP1) influences the cellular phenotype and fate through precise and timely regulation of MAPK activity within various cell types and tissues, yet its role in lung fibroblasts and pulmonary fibrosis has not been explored. Using gain- and loss-of-function studies, we found that MKP1 promoted lung MF dedifferentiation and restored the sensitivity of these cells to apoptosis - effects determined to be mainly dependent on MKP1's dephosphorylation of p38α MAPK (p38α). Fibroblast-specific deletion of MKP1 following peak bleomycin-induced lung fibrosis largely abrogated its subsequent spontaneous resolution. Such resolution was restored by treating these transgenic mice with the p38α inhibitor VX-702. We conclude that MKP1 is a critical antifibrotic brake whose inhibition of pathogenic p38α in lung fibroblasts is necessary for fibrosis resolution following lung injury.

Trinity of inflammation, innate immune cells and cross-talk of signalling pathways in tumour microenvironment

Unresolved inflammation is a pathological consequence of persistent inflammatory stimulus and perturbation in regulatory mechanisms. It increases the risk of tumour development and orchestrates all stages of tumorigenesis in selected organs. In certain cancers, inflammatory processes create the appropriate conditions for neoplastic transformation. While in other types, oncogenic changes pave the way for an inflammatory microenvironment that leads to tumour development. Of interest, hallmarks of tumour-promoting and cancer-associated inflammation are striking similar, sharing a complex network of stromal (fibroblasts and vascular cells) and inflammatory immune cells that collectively form the tumour microenvironment (TME). The cross-talks of signalling pathways initially developed to support homeostasis, change their role, and promote atypical proliferation, survival, angiogenesis, and subversion of adaptive immunity in TME. These transcriptional and regulatory pathways invariably contribute to cancer-promoting inflammation in chronic inflammatory disorders and foster "smouldering" inflammation in the microenvironment of various tumour types. Besides identifying common target sites of numerous cancer types, signalling programs and their cross-talks governing immune cells' plasticity and functional diversity can be used to develop new fate-mapping and lineage-tracing mechanisms. Here, we review the vital molecular mechanisms and pathways that establish the connection between inflammation and tumour development, progression, and metastasis. We also discussed the cross-talks between signalling pathways and devised strategies focusing on these interaction mechanisms to harness synthetic lethal drug combinations for targeted cancer therapy.

Ubiquitin-specific protease 35 (USP35) mediates cisplatin-induced apoptosis by stabilizing BIRC3 in non-small cell lung cancer

Ubiquitin-specific protease 35 (USP35) is a member of the ubiquitin-specific protease family (USP), which influences the progression of multiple cancers by deubiquitinating a variety of substrates. In recent years, the specific role of USP35 was begun to be understood. In this study, we investigated the role and underlying molecular mechanisms of USP35 in chemoresistance of non-small cell lung cancer (NSCLC) to cisplatin. Depletion of USP35 increased the sensitivity of NSCLC to cisplatin-induced apoptosis. We screened and identified a potential substrate of USP35, baculoviral IAP repeat containing 3 (BIRC3). Overexpression of USP35 in H460 cells increased the abundance of BIRC3, while USP35 knockdown in Anip973 cells decreased BIRC3 abundance. Notably, USP35 directly interacted with and stabilized BIRC3 through lys48-mediated polyubiquitination via its deubiquitinating enzyme activity. USP35 alleviated cisplatin-induced cell apoptosis by regulating BIRC3 levels in NSCLC cells. Moreover, a significant positive correlation between USP35 and BIRC3 protein expression levels was observed in human NSCLC tissues. Taken together, USP35 plays a vital role in resistance to cisplatin-induced cell death through the overexpression of BIRC3. USP35 might be a potentially novel therapeutic target in human NSCLC.

Microribonucleic Acid-15a-5p Alters Adriamycin Resistance in Breast Cancer Cells by Targeting Cell Division Cycle-Associated Protein 4

Objective

Although chemotherapy is one of the first line clinical treatment of tumors, the efficacy of chemotherapy has been severely restricted by the frequent occurrence of drug resistance phenomenon. Multiple studies found that miRNAs can regulate the chemosensitivity of tumor cells. Here, this study aimed to assess the potential role of the miR-15a-5p/cell division cycle-related protein 4 (CDCA4) axis in breast cancer (BC) resistance to Adriamycin.

Methods

In the present study, the relative expression of miRNA-15a-5p in MCF-7/ADR, MCF-7 and Hs578Bst was measured by qRT-PCR. MCF-7/ADR cells underwent transfection with an miR-15a-5p mimic and inhibitor, respectively. Transwell assays, flow cytometry and CCK8 were performed to examine the potential effects of the abnormal expression of miR-15a-5p. The association of aberrant miR-15a-5p expression with Adriamycin resistance in BC was determined in cultured MCF-7/ADR cells. Bioinformatics was employed to predict the genes targeted by miR-15a-5p. Moreover, the correlation between miR-15a-5p and its target gene, CDCA4, was evaluated based on qRT-PCR data.

Results

The expression of miR-15a-5p was significantly downregulated in MCF/ADR cells compared with MCF-7 and Hs578Bst cell lines. In the presence of Adriamycin, miR-15a-5p overexpression significantly increased cell chemosensitivity, as well as MCF-7/ADR cell proliferation, invasion, and migration, while promoting apoptosis and inducing cell-cycle arrest in the synthesis phase. CDCA4 RNA interference enhanced these effects as shown in our previous study. Bioinformatics identified CDCA4 as an miR-15a-5p target gene. qRT-PCR further demonstrated that CDCA4 and miR-15a-5p expression levels were inversely correlated.

Conclusion

Adriamycin resistance in BC cells was, at least in part, altered by mRNA-15a-5p via regulation of its target gene, CDCA4, by controlling the cell cycle, which may provide some novel ideas for BC chemotherapy in the future.

Role of NRF2 in Lung Cancer

The gene expression program induced by NRF2 transcription factor plays a critical role in cell defense responses against a broad variety of cellular stresses, most importantly oxidative stress. NRF2 stability is fine-tuned regulated by KEAP1, which drives its degradation in the absence of oxidative stress. In the context of cancer, NRF2 cytoprotective functions were initially linked to anti-oncogenic properties. However, in the last few decades, growing evidence indicates that NRF2 acts as a tumor driver, inducing metastasis and resistance to chemotherapy. Constitutive activation of NRF2 has been found to be frequent in several tumors, including some lung cancer sub-types and it has been associated to the maintenance of a malignant cell phenotype. This apparently contradictory effect of the NRF2/KEAP1 signaling pathway in cancer (cell protection against cancer versus pro-tumoral properties) has generated a great controversy about its functions in this disease. In this review, we will describe the molecular mechanism regulating this signaling pathway in physiological conditions and summarize the most important findings related to the role of NRF2/KEAP1 in lung cancer. The focus will be placed on NRF2 activation mechanisms, the implication of those in lung cancer progression and current therapeutic strategies directed at blocking NRF2 action.

Danggui Buxue Decoction enhances the anticancer activity of gemcitabine and alleviates gemcitabine-induced myelosuppression

ETHNOPHARMACOLOGICAL RELEVANCE

Danggui Buxue Decoction (DBD) as a traditional Chinese medicine (TCM) has been widely used to treat blood deficiency. With the immune regulation and hematopoietic effect, DBD improved the quality of life in non-small-cell lung cancer (NSCLC) patients. We previously reported that DBD sensitized the response of NSCLC to Gemcitabine (Gem); however, the synergism and attenuation mechanism on the combination of Gem and DBD has not yet been elucidated.

AIM OF THE STUDY

To investigate the mechanisms of DBD in enhancing the anticancer activity of Gem and alleviating Gem-induced myelosuppression.

MATERIALS AND METHODS

A549 nude mice model was established to study the effect on the combination of Gem and DBD. The organ indices, peripheral blood cells and the hematopoiesis-related cytokines were analyzed in Gem-induced myelosuppressive mice. Then we studied the whole process from Gem-induced bone marrow suppression to self-healing, and the mechanism of DBD's attenuation by the experiments of bone marrow nucleated cells (BMNCs).

RESULTS

There were an enhanced anticancer effect and an improvement of hematopoietic function by combining of Gem and DBD in A549 nude mice model. DBD regulated Hu antigen R (HuR), deoxycytidine kinase (dCK) and nuclear factor erythroid 2-related factor (Nrf2), increased the expression of thrombopoietin (TPO) and granulocyte-macrophage colony stimulating factor (GM-CSF). For Gem-induced myelosuppressive mice, DBD improved the number of peripheral blood cells and the levels of hematopoiesis-related cytokines. Moreover, DBD was observed to reduce deoxyribonucleic acid (DNA) content at the G1 phase, promoted BMNCs proliferation and up-regulated cycle-related proteins.

CONCLUSIONS

The results indicated that DBD not only improved the sensitivity of Gem but also alleviated Gem-induced myelosuppression. This study may provide a pharmacological basis for the combination of DBD and Gem in clinical application.

Nrf2 signaling pathway in cisplatin chemotherapy: Potential involvement in organ protection and chemoresistance

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a vital transcription factor and its induction is of significant importance for protecting against oxidative damage. Increased levels of Reactive Oxygen Species (ROS) stimulate Nrf2 signaling, enhancing the activity of antioxidant enzymes such as catalase, superoxide dismutase and glutathione peroxidase. These enzymes are associated with retarding oxidative stress. On the other hand, Nrf2 activation in cancer cells is responsible for the development of chemoresistance due to disrupting oxidative mediated-cell death by reducing ROS levels. Cisplatin (CP), cis-diamminedichloroplatinum(II), is a potent anti-tumor agent extensively used in cancer therapy, but its frequent application leads to the development of chemoresistance as well. In the present study, association of Nrf2 signaling with chemoresistance to CP and protection against its deleterious effects is discussed. Anti-tumor compounds, mainly phytochemicals, retard chemoresistance by suppressing Nrf2 signaling. Upstream mediators such as microRNAs can regulate Nrf2 expression during CP chemotherapy regimens. Protection against side effects of CP is mediated via activating Nrf2 signaling and its downstream targets activating antioxidant defense system. Protective agents that activate Nrf2 signaling, can ameliorate CP-mediated ototoxicity, nephrotoxicity and neurotoxicity. Reducing ROS levels and preventing cell death are the most important factors involved in alleviating CP toxicity upon Nrf2 activation. As pre-clinical experiments advocate the role of Nrf2 in chemoprotection and CP resistance, translating these findings to the clinic can provide a significant progress in treatment of cancer patients.

Prognostic and clinicopathological significance of NRF2 expression in non-small cell lung cancer: A meta-analysis

Nuclear factor erythroid 2-related factor 2 (NRF2) functions as a transcription factor and regulates a wide array of antioxidant and stress-responsive genes. NRF2 has been widely implicated in different types of cancers, but only limited studies concerning the relationship between NRF2 expression and tumour invasion or prognosis in lung cancer. Therefore, we conducted a meta-analysis to determine the prognostic value of NRF2 in patients with non-small cell lung cancer (NSCLC). The relationship between NRF2 expression in NSCLC patients and clinicopathological features was also investigated. Overall survival (OS) and treatment response rate were evaluated using STATA software. Twenty eligible articles with 2530 lung cancer patients were included in this meta-analysis. The results revealed that high expression level of NRF2 was associated with pathologic distant metastasis (odds ratio (OR) = 2.64, 95% confidence interval (CI) 1.62-4.31; P < 0.001), lymph node metastasis (OR = 2.14, 95% CI: 1.53-3.00; P < 0.001), and tumour node metastasis (TNM) stage (OR = 1.95, 95% CI: 1.52-2.49, P < 0.001). High NRF2 expression was associated with low treatment response rate in platinum-based chemotherapy (HR = 0.11, 95% CI 0.02-0.51; P = 0.005). High expression level of NRF2 is predictive for poor overall survival rate (HR = 1.86, 95% CI 1.44-2.41, P < 0.001) and poor progression-free survival (PFS) (HR = 2.27, 95% CI 1.26-4.09, P = 0.006). Compared to patients with a low level of NRF2 expression, patients with high NRF2 expression levels were associated with worse OS and PFS when given the chemotherapy or EGFR-TKI. Together, our meta-analysis results suggest that NRF2 can act as a potential indicator of NSCLC tumour aggressiveness and help the prognosis and design of a better treatment strategy for NSCLC patients.

The therapeutic value of XL388 in human glioma cells

XL388 is a highly efficient and orally-available ATP-competitive PI3K-mTOR dual inhibitor. Its activity against glioma cells was studied here. In established and primary human glioma cells, XL388 potently inhibited cell survival and proliferation as well as cell migration, invasion and cell cycle progression. The dual inhibitor induced significant apoptosis activation in glioma cells. In A172 cells and primary human glioma cells, XL388 inhibited Akt-mTORC1/2 activation by blocking phosphorylation of Akt and S6K1. XL388-induced glioma cell death was only partially attenuated by a constitutively-active mutant Akt1. Furthermore, it was cytotoxic against Akt1-knockout A172 glioma cells. XL388 downregulated MAF bZIP transcription factor G (MAFG) and inhibited Nrf2 signaling, causing oxidative injury in glioma cells. Conversely, antioxidants, n-acetylcysteine, pyrrolidine dithiocarbamate and AGI-106, alleviated XL388-induced cytotoxicity and apoptosis in glioma cells. Oral administration of XL388 inhibited subcutaneous A172 xenograft growth in severe combined immunodeficient mice. Akt-S6K1 inhibition and MAFG downregulation were detected in XL388-treated A172 xenograft tissues. Collectively, XL388 efficiently inhibits human glioma cell growth, through Akt-mTOR-dependent and -independent mechanisms.

MicroRNAs and Their Influence on the ZEB Family: Mechanistic Aspects and Therapeutic Applications in Cancer Therapy

Molecular signaling pathways involved in cancer have been intensively studied due to their crucial role in cancer cell growth and dissemination. Among them, zinc finger E-box binding homeobox-1 (ZEB1) and -2 (ZEB2) are molecules that play vital roles in signaling pathways to ensure the survival of tumor cells, particularly through enhancing cell proliferation, promoting cell migration and invasion, and triggering drug resistance. Importantly, ZEB proteins are regulated by microRNAs (miRs). In this review, we demonstrate the impact that miRs have on cancer therapy, through their targeting of ZEB proteins. MiRs are able to act as onco-suppressor factors and inhibit the malignancy of tumor cells through ZEB1/2 down-regulation. This can lead to an inhibition of epithelial-mesenchymal transition (EMT) mechanism, therefore reducing metastasis. Additionally, miRs are able to inhibit ZEB1/2-mediated drug resistance and immunosuppression. Additionally, we explore the upstream modulators of miRs such as long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), as these regulators can influence the inhibitory effect of miRs on ZEB proteins and cancer progression.