Suberoylanilide hydroxamic acid overcomes erlotinib-acquired resistance via phosphatase and tensin homolog deleted on chromosome 10-mediated apoptosis in non-small cell lung cancer

Pathogenic role of super-enhancers as potential therapeutic targets in lung cancer

Lung cancer is still one of the deadliest malignancies today, and most patients with advanced lung cancer pass away from disease progression that is uncontrollable by medications. Super-enhancers (SEs) are large clusters of enhancers in the genome's non-coding sequences that actively trigger transcription. Although SEs have just been identified over the past 10 years, their intricate structure and crucial role in determining cell identity and promoting tumorigenesis and progression are increasingly coming to light. Here, we review the structural composition of SEs, the auto-regulatory circuits, the control mechanisms of downstream genes and pathways, and the characterization of subgroups classified according to SEs in lung cancer. Additionally, we discuss the therapeutic targets, several small-molecule inhibitors, and available treatment options for SEs in lung cancer. Combination therapies have demonstrated considerable advantages in preclinical models, and we anticipate that these drugs will soon enter clinical studies and benefit patients.

Microbiome dysbiosis and epigenetic modulations in lung cancer: From pathogenesis to therapy

The lung microbiome plays an essential role in maintaining healthy lung function, including host immune homeostasis. Lung microbial dysbiosis or disruption of the gut-lung axis can contribute to lung carcinogenesis by causing DNA damage, inducing genomic instability, or altering the host's susceptibility to carcinogenic insults. Thus far, most studies have reported the association of microbial composition in lung cancer. Mechanistic studies describing host-microbe interactions in promoting lung carcinogenesis are limited. Considering cancer as a multifaceted disease where epigenetic dysregulation plays a critical role, epigenetic modifying potentials of microbial metabolites and toxins and their roles in lung tumorigenesis are not well studied. The current review explains microbial dysbiosis and epigenetic aberrations in lung cancer and potential therapeutic opportunities.

Histone deacetylases modulate resistance to the therapy in lung cancer

The acetylation status of histones located in both oncogenes and tumor suppressor genes modulate cancer hallmarks. In lung cancer, changes in the acetylation status are associated with increased cell proliferation, tumor growth, migration, invasion, and metastasis. Histone deacetylases (HDACs) are a group of enzymes that take part in the elimination of acetyl groups from histones. Thus, HDACs regulate the acetylation status of histones. Although several therapies are available to treat lung cancer, many of these fail because of the development of tumor resistance. One mechanism of tumor resistance is the aberrant expression of HDACs. Specific anti-cancer therapies modulate HDACs expression, resulting in chromatin remodeling and epigenetic modification of the expression of a variety of genes. Thus, HDACs are promising therapeutic targets to improve the response to anti-cancer treatments. Besides, natural compounds such as phytochemicals have potent antioxidant and chemopreventive activities. Some of these compounds modulate the deregulated activity of HDACs (e.g. curcumin, apigenin, EGCG, resveratrol, and quercetin). These phytochemicals have been shown to inhibit some of the cancer hallmarks through HDAC modulation. The present review discusses the epigenetic mechanisms by which HDACs contribute to carcinogenesis and resistance of lung cancer cells to anticancer therapies.

Deubiquitylase OTUD1 confers Erlotinib sensitivity in non-small cell lung cancer through inhibition of nuclear translocation of YAP1

Evidence exists suggesting tumor-inhibiting properties of deubiquitylase OTUD1 in various malignancies. We herein investigated the anti-tumor effect and clarified the downstream mechanisms of OTUD1 in the chemoresistance of non-small cell lung cancer (NSCLC) cells. Expression of OTUD1 was examined in NSCLC (PC-9 cells) and erlotinib-resistant NSCLC (PC-9/ER) cell lines. OTUD1 was bioinformatically predicted to be weakly expressed in NSCLC tissue samples and verified in PC-9/ER cells. PC-9/ER cells were subsequently subjected to ectopic expression of OTUD1 alone or combined with SOX9 to dissect out the effect of OTUD1 on the proliferation, chemoresistance and apoptosis in vitro and in vivo. OTUD1 upregulation sensitized NSCLC cells to erlotinib both in vitro and in vivo. In the presence of OTUD1 overexpression, nuclear translocation of YAP1 was inhibited and its expression was inactivated. This effect of OTUD1 was associated with the decreased ubiquitination level of YAP1. SOX9/SPP1 inactivation was the consequence of inhibited nuclear translocation of YAP1. Overexpression of SOX9 reversed the inhibitory effect of OTUD1 on the resistance of NSCLC cells to erlotinib. In conclusion, our study reveals that OTUD1 potentially acts as a tumor suppressor and suppresses erlotinib resistance of NSCLC through the YAP1/SOX9/SPP1 axis, suggesting that OTUD1 may serve as a target for reducing chemoresistance for NSCLC.

The biochemical and clinical implications of phosphatase and tensin homolog deleted on chromosome ten in different cancers

Phosphatase and tensin homolog deleted on chromosome ten (PTEN) is widely known as a tumor suppressor gene. It is located on chromosome 10q23 with 200 kb, and has dual activity of both protein and lipid phosphatase. In addition, as a targeted gene in multiple pathways, PTEN has a variety of physiological activities, such as those regulating the cell cycle, inducing cell apoptosis, and inhibiting cell invasion, etc. The PTEN gene have been identified in many kinds of cancers due to its mutations, deletions and inactivation, such as lung cancer, liver cancer, and breast cancer, and they are closely connected with the genesis and progression of cancers. To a large extent, the tumor suppressive function of PTEN is realized through its inhibition of the PI3K/AKT signaling pathway which controls cells apoptosis and development. In addition, PTEN loss has been associated with the prognosis of many cancers, such as lung cancer, liver cancer, and breast cancer. PTEN gene is related to many cancers and their pathological development. On the basis of a large number of related studies, this study describes in detail the structure, regulation, function and classical signal pathways of PTEN, as well as the relationship between various tumors related to PTEN. In addition, some drug studies targeting PTEN/PI3K/AKT/mTOR are also introduced in order to provide some directions for experimental research and clinical treatment of tumors.

Inhibition of miR-185-3p Confers Erlotinib Resistance Through Upregulation of PFKL/MET in Lung Cancers

Erlotinib (ER), as an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), has a significant therapeutic effect in lung cancers. However, EGFR TKI resistance inevitably occurs after treatment for approximately 12 months, which weakens its antitumor effect. Here, we identified miR-185-3p as a significantly downregulated microRNA responsible for acquired EGFR TKI resistance in cells and patients with lung cancer. qRT-PCR and Western Blot were performed to determine the relative expression of miR-185-3p in ER-resistant tumor tissues and cells. The viability and apoptosis of lung cancer cells were evaluated by Cell Counting Kit-8 (CCK8) assay and flow cytometry, respectively. The binding between miR-185-3p and liver-type phosphofructokinase (PFKL) was verified by dual luciferase assay. It was found that overexpression of miR-185-3p conferred ER sensitivity in lung cancer cell lines. MiR-185-3p was downregulated in ER-resistant lung cancer cells (H1299/ER and A549/ER). MiR-185-3p inhibited proliferation and induced cell apoptosis in ER-resistant cells. Mechanistically, miR-185-3p downregulation contributed to ER resistance through upregulating the PFKL. Moreover, Mesenchymal to epithelial transition (MET) oncoprotein promoted EGFR-TKI resistance by regulating miR-185-3p and PFKL. These findings revealed a novel mechanism in which downregulation of miR-185-3p may induce overexpression of PFKL and MET and confer ER resistance in lung cells. Combination of PFKL/MET inhibitors and EGFR TKIs could be a rational therapeutic approach for lung cancer patients with EGFR mutation.

miR-1/133a and miR-206/133b clusters overcome HGF induced gefitinib resistance in non-small cell lung cancers with EGFR sensitive mutations

It has been reported that clustered miRNAs can be transcribed coordinately and exhibit similar functions by regulating the same targets. miR-1/133a and miR-206/133b are well-characterized miRNA clusters. However, the effect of these clusters on EGFR-TKI resistance is not clear. In this study, we demonstrated that lentivirus-mediated HGF overexpression was able to induce gefitinib resistance in non-small cell lung cancers with EGFR sensitive mutations. miR-1/133a and miR-206/133b clusters could overcome HGF induced gefitinib resistance. Furthermore, the clusters were more effective than individual miRNA. Transcriptome RNA sequencing and bioinformatics analysis revealed that multiple pathways, including 'EGFR tyrosine kinase inhibitor resistance' pathway, were involved in anti-resistance mechanisms of miR-1/133a and miR-206/133b clusters. Western blotting results confirmed the inhibitory effect of miRNA clusters on MET expression and downstream pathway activation. In conclusion, miR-1/133a and miR-206/133b clusters are able to exhibit the synergetic effect on overcoming HGF-induced gefitinib resistance in NSCLC and the mechanisms are through targeting multiple genes related to gefitinib resistance.

Vorinostat-loaded titanium oxide nanoparticles (anatase) induce G2/M cell cycle arrest in breast cancer cells via PALB2 upregulation

Breast cancer is a group of diseases in which cells divide out of controlled, typically resulting in a mass. Erlotinib is targeted cancer drug which functions as an inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase. It is used mainly to treat of non-small cell lung cancer patients and has an action against pancreatic cancer. Vorinostat (aka suberanilohydroxamic acid) is an inhibitor of histone deacetylases (HDAC), which has an epigenetic modulation activity. It is used to treat cutaneous T cell lymphoma. In the present study, the erlotinib (ERL) and vorinostat (SAHA) loaded TiO₂ nanoparticles (NPs) were used for the treatment of the breast cancer cells (MDA-MB-231 and MCF-7) and human cancerous amniotic cells (WISH). Cell count and viability were negatively affected in all treatments compared to normal cells and bare TiO₂ NPs. Apoptosis results indicated a significant increase in the total apoptosis in all treatments compared with control cells. ERL- and SAHA-loaded TiO₂ NPs treatments arrested breast cancer cells at G2/M phase, which indicate the cytotoxic effect of these treatment. Partner and localizer of BRCA2 (PALB2) gene expression was assessed using qPCR. The results indicate that PLAB2 was upregulated in ERL- and SAHA-loaded TiO₂ NPs compared with control cells and can be used as nanocarrier for chemotherapy drugs. However, this conclusion necessitates further confirmative investigation.