ERK1/2 is activated in non-small-cell lung cancer and associated with advanced tumours

Tracing the evolution of single-cell cancer 3D genomes: an atlas for cancer gene discovery

Although three-dimensional (3D) genome structures are altered in cancer cells, little is known about how these changes evolve and diversify during cancer progression. Leveraging genome-wide chromatin tracing to visualize 3D genome folding directly in tissues, we generated 3D genome cancer atlases of murine lung and pancreatic adenocarcinoma. Our data reveal stereotypical, non-monotonic, and stage-specific alterations in 3D genome folding heterogeneity, compaction, and compartmentalization as cancers progress from normal to preinvasive and ultimately to invasive tumors, discovering a potential structural bottleneck in early tumor progression. Remarkably, 3D genome architectures distinguish histologic cancer states in single cells, despite considerable cell-to-cell heterogeneity. Gene-level analyses of evolutionary changes in 3D genome compartmentalization not only showed compartment-associated genes are more homogeneously regulated, but also elucidated prognostic and dependency genes in lung adenocarcinoma and a previously unappreciated role for polycomb-group protein Rnf2 in 3D genome regulation. Our results demonstrate the utility of mapping the single-cell cancer 3D genome in tissues and illuminate its potential to identify new diagnostic, prognostic, and therapeutic biomarkers in cancer.

Immunomodulatory effects of BAFF and APRIL cytokines in post-pulmonary infection lung cancer: Implications for drug resistance and progression

Lung cancer is a complicated and challenging disease and is one of the most common causes of cancer-related mortality worldwide. Within the lung microenvironment, specific cytokines, including the B cell activation factor (BAFF) and the A proliferation-inducing ligand (APRIL), are produce by various cells, notably airway epithelial cells, in response allergic inflammation or pulmonary infection. These cytokines play a critical role in maintaining local immune responses and fostering the survival of immune cells. The BAFF and APRIL system have been connected in a range of malignancies and have shown their potential in inducing drug resistance and promoting cancer progression. This review highlights recent studies on the involvement of BAFF and APRIL in various cancers, focusing mainly on their role in lung cancer, and discusses the possibility of these molecules in contributing to drug resistance and cancer progression following pulmonary infection. We suggest consideration the targeting BAFF and APRIL or their respective receptors as promising novel therapies for effective treatment of lung cancer, especially post pulmonary infection. However, it remains important to conduct further investigations to fully elucidate the precise mechanisms underlying how the BAFF and APRIL systems enhance cancer survival and drug resistance subsequent pulmonary infections.

Papillary renal neoplasm with reverse polarity: a clinicopathologic study of 43 cases with a focus on the expression of KRAS signaling pathway downstream effectors

Papillary renal neoplasm with reverse polarity (PRNRP) is a renal tumor with frequent KRAS mutations. In this study, we aimed to report the clinical, histological, and immunohistochemical characteristics of PRNRP and the protein expression of various KRAS signaling pathway downstream effectors in PRNRP. PRNRP samples from patients who underwent surgical resection at Seoul National University Hospital over an 11-year period (January 2011 to December 2021) were analyzed. We identified 43 PRNRPs, defined as papillary renal tumors with a thin papillary architecture, eosinophilic finely granular cytoplasm, and apical nuclear position. Immunohistochemistry revealed typical characteristics of PRNRP, including exclusively positive GATA3 (43/43); highly positive L1CAM (43/43), PAX8 (43/43), and EMA (43/43); and low positive AMACR (4/43), RCC (1/43), and vimentin (1/43). KRAS signaling pathway effectors, such as p-ERK, RalA, and RalB, were highly expressed in PRNRP compared to papillary renal cell carcinoma (pRCC) with low or high nuclear grade (P < .001, all). Compared to pRCC with high nuclear grade, patients with PRNRP exhibited significantly longer progression-free survival (P < .001). PRNRP showed the best clinical outcome, with no disease progression in any of the cases. Our study analyzed the largest number of PRNRP cases and is the first to analyze the association between PRNRP and the KRAS downstream signaling pathway. PRNRP was found at a high frequency among all papillary renal tumors (43/207) and demonstrated a very good prognosis. PRNRP showed high GATA3, L1CAM, PAX8, and EMA protein expression as well as high p-ERK, RalA, and RalB protein expression.

Phosphorylated nuclear DICER1 promotes open chromatin state and lineage plasticity of AT2 tumor cells in lung adenocarcinomas

KRAS/ERK pathway phosphorylates DICER1, causing its nuclear translocation, and phosphomimetic Dicer1 contributes to tumorigenesis in mice. Mechanisms through which phospho-DICER1 regulates tumor progression remain undefined. While DICER1 canonically regulates microRNAs (miRNA) and epithelial-to-mesenchymal transition (EMT), we found that phosphorylated nuclear DICER1 (phospho-nuclear DICER1) promotes late-stage tumor progression in mice with oncogenic Kras, independent of miRNAs and EMT. Instead, we observe that the murine AT2 tumor cells exhibit altered chromatin compaction, and cells from disorganized advanced tumors, but not localized tumors, express gastric genes. Collectively, this results in subpopulations of tumor cells transitioning from a restricted alveolar to a broader endodermal lineage state. In human LUADs, we observed expression of phospho-nuclear DICER1 in advanced tumors together with the expression of gastric genes. We define a multimeric chromatin-DICER1 complex composed of the Mediator complex subunit 12, CBX1, MACROH2A.1, and transcriptional regulators supporting the model that phospho-nuclear DICER1 leads to lineage reprogramming of AT2 tumor cells to mediate lung cancer progression.

Using a Single Peptide to Electrochemically Sense Multiple Kinases

Kinases are responsible for regulating cellular and physiological processes, and abnormal kinase activity is associated with various diseases. Therefore, kinases are being used as biomarkers for disease and developing methods for their sensing is highly important. Usually more than one kinase is involved in phosphorylating a target protein. However, kinase detection methods usually detect the activity of only one specific kinase. Here we describe an electrochemical kinase sensing tool for the selective detection of two kinases using the same target peptide. We demonstrate the sensing of kinases ERK2 and PKCδ. This is based on a single sensing element, a peptide that contains two distinct phosphorylation sites of these two kinases. Reversibility experiments with alkaline phosphatase and reaction with the electrochemically active ferrocene-labeled ATP showed that the mechanism of sensing is by detecting the enzymatic phosphorylation. Our approach can be further utilized to develop devices for the detection of multiple kinases and can be expanded to other types of enzymes involved in disease.

Effects of CYP3A43 Expression on Cell Proliferation and Migration of Lung Adenocarcinoma and Its Clinical Significance

The cytochrome P450s (CYP450s) include key oxidative enzymes involved in the metabolism of various carcinogens and anticancer drugs. Bioinformatic studies have demonstrated the association of CYP3A43 with liver cancer and ovarian cancer. However, the biological function of CYP3A43 in tumor progression remains unclear. To further reveal the role of CYP3A43 in tumor progression, we first analyzed the data from the UALCAN database and found that CYP3A43 was negatively correlated to the cancer staging and lymph node metastasis of lung adenocarcinoma (LUAD). We established stable CYP3A43-knockdown LUAD H1299 cell line and found that its knockdown enhanced cell proliferation, colony formation, and migration in vitro, and promoted the growth of tumor xenograft in vivo. Interestingly, when CYP3A43 was ectopically-expressed in the LUAD cell lines, decreased cell proliferation and ERK1/2 phosphorylation level were observed. Lastly, we also identified CYP3A43 co-expressed genes in LUAD from LinkedOmics database followed by GO and KEGG analyses. In conclusion, our results indicate the unprecedented role of CYP3A43 in the suppression of LUAD and provide new possibilities for targeted therapy of this life-threatening disease.

Upregulation of KLHL17 promotes the proliferation and migration of non-small cell lung cancer by activating the Ras/MAPK signaling pathway

Analysis of the Gene Expression Profiling Interactive Analysis (GEPIA) database revealed that Kelch-like 17 (KLHL17) is overexpressed in non-small cell lung cancer (NSCLC) including adenocarcinoma (ADC) and squamous cell carcinoma (SCC). We therefore explored the role of KLHL17 in the development and progression of NSCLC. Immunohistochemistry and western blotting showed that KLHL17 expression was significantly higher in the tumor tissues from 173 patients with NSCLC, compared with the corresponding non-neoplastic tissue. In addition, upregulated KLHL17 expression was positively correlated with tumor size, lymph node metastasis and tumor node metastasis (TNM) stage, and affected the overall survival (OS) of patients with NSCLC. Consistent with clinical samples, in vitro studies demonstrated that KLHL17 expression was higher in various cell lines of NSCLC (A549, H1299, H460 and SK cells) as compared to normal human bronchial epithelial cells (HBE cells). Overexpression of KLHL17 in the cell lines of NSCLC with KLHL17-Flag plasmid promoted the proliferation and migration of tumor cells, which was associated with elevated activation of Rat sarcoma/Mitogen-activated protein kinases (Ras/MAPK) signaling and increased expression of cyclin D1, cyclin D-dependent kinases 4 (CDK4), matrix metalloproteinase 2 (MMP2) and Ras homolog gene family member A (RhoA). In contrast, knockdown of KLHL17 in the cell lines of NSCLC using KLHL17 small interfering RNA suppressed the proliferation and migration of tumor cells, in association with reduced activation of Ras/MAPK signaling and decreased expression of cyclin D1, CDK4, MMP2 and RhoA. Moreover, treatment of tumor cells with Ras inhibitor salirasib prevented KLHL17-induced Ras/MAPK activity as well as tumor proliferation and migration. These results suggest that upregulated KLHL17 in NSCLC promotes the proliferation and migration of tumor by activating Ras/MAPK signaling pathway. Therefore, KLHL17 may be a novel therapeutic target for the treatment of NSCLC.

Role of a Disease-associated ST3Gal-4 in Non-small Cell Lung Cancer

Sialylation promotes tumorigenesis by affecting various cancer-related events, including apoptosis inhibition, cell growth, invasion, migration, metastasis, chemo-resistance, and immunomodulation in favor of tumor progression. An altered expression of sialyltransferase enzymes is responsible for synthesizing various tumor-associated sialylated structures. In the present study, our findings have revealed a significant up-regulation of ST3Gal-4 transcript in the two major subtypes of NSCLC cell lines [squamous cell carcinoma cell line (NCI-H520) and adenocarcinoma cell line (A549)]. Thus, the role of the ST3Gal-4 gene was assessed on cancer-associated signal transduction pathways in these cells in view of proliferation, invasion, and migration. ST3Gal-4 was silenced by transfection of both the cell lines with esi-ST3Gal-4-RNA, which RT-PCR and western immunoblotting confirmed. Silencing of ST3Gal-4 resulted in a decreased expression of MAL-I interacting membrane-HSP60, identified earlier as an α2,3-sialylated glycoprotein, thus pointing towards the possible role of ST3Gal-4 in its sialylation. The proliferation, invasion, and migration of both types of NSCLC cells were reduced significantly in the ST3Gal-4 silenced cells. Our findings were substantiated by the down-regulation of β-catenin and E-cadherin, a reduced expression of activated AKT1, ERK1/2, and NF-ƙB in these cells. We propose that ST3Gal-4 may be the disease-associated sialyltransferase involved in α2,3 sialylation of the membrane proteins, including HSP60 of the NSCLC cells. This may lead to the conformational alteration of these proteins, required for the activation of E-cadherin/β-catenin, AKT, and ERK/NF-ƙB mediated signal transduction pathways in these cells, resulting in their proliferation, invasion, and migration.

Aquaporins in Cancer Biology

Aquaporins (AQPs) are a family of transmembrane water channel proteins, which were initially characterized as a novel protein family that plays a vital role in transcellular and transepithelial water movement. AQP1, AQP2, AQP4, AQP5, and AQP8 are primarily water selective, whereas AQP3, AQP7, AQP9, and AQP10 (called “aqua-glyceroporins”) also transport glycerol and other small solutes. Recently, multiple reports have suggested that AQPs have important roles in cancer cell growth, migration, invasion, and angiogenesis, each of which is important in human carcinogenesis. Here, we review recent data concerning the involvement of AQPs in tumor growth, angiogenesis, and metastasis and explore the expression profiles from various resected cancer samples to further dissect the underlying molecular mechanisms. Moreover, we discuss the potential role of AQPs during the development of genomic instability and performed modeling to describe the integration of binding between AQPs with various SH3 domain binning adaptor molecules. Throughout review and discussion of numerous reports, we have tried to provide key evidence that AQPs play key roles in tumor biology, which may provide a unique opportunity in designing a novel class of anti-tumor agents.

Fbxo45-mediated NP-STEP46 degradation via K6-linked ubiquitination sustains ERK activity in lung cancer

Lung cancer is one of the most threatening malignant tumors to human health. Epidermal growth factor receptor (EGFR)‐targeted therapy is a common and essential means for the clinical treatment of lung cancer. However, drug resistance has always affected the therapeutic effect and survival rate in non‐small cell lung cancer (NSCLC). Tumor heterogeneity is a significant reason, yielding various drug resistance mechanisms, such as EGFR‐dependent or ‐independent extracellular signal‐regulated kinase 1 and/or 2 (ERK1/2) activation in NSCLC. To examine whether this aberrant activation of ERK1/2 is related to the loss of function of its specific phosphatase, a series of in vitro and in vivo assays were performed. We found that F‐box/SPRY domain‐containing protein 1 (Fbxo45) induces ubiquitination of NP‐STEP₄₆, an active form of striatal‐enriched protein tyrosine phosphatase, with a K6‐linked poly‐ubiquitin chain. This ubiquitination led to proteasome degradation in the nucleus, which then sustains the aberrant level of phosphorylated‐ERK (pERK) and promotes tumor growth of NSCLC. Fbxo45 silencing can significantly inhibit cell proliferation and tumor growth. Moreover, NSCLC cells with silenced Fbxo45 showed great sensitivity to the EGFR tyrosine kinase inhibitor (TKI) afatinib. Here, we first report this critical pERK maintenance mechanism, which might be independent of the upstream kinase activity in NSCLC. We propose that inhibiting Fbxo45 may combat the issue of drug resistance in NSCLC patients, especially combining with EGFR‐TKI therapy.

IGF1R acts as a cancer-promoting factor in the tumor microenvironment facilitating lung metastasis implantation and progression

Given the long-term ineffectiveness of current therapies and late-stage diagnoses, lung cancer is a leading cause of malignant diseases. Tumor progression is influenced by cancer cell interactions with the tumor microenvironment (TME). Insulin-like growth factor 1 receptor (IGF1R) was reported to affect the TME; however, the role of IGF1R in lung TME has not been investigated. First, we assessed IGF1R genomic alterations and expression in NSCLC patient tissue samples, as well as IGF1R serum levels. Next, we performed tumor heterotopic transplantation and pulmonary metastases in IGF1R-deficient mice using melanoma and Lewis lung carcinoma (LLC) cells. Herein we report increased amplification and mRNA expression, as well as increased protein expression (IGF1R/p-IGF1R) and IGF1R levels in tumor samples and serum from NSCLC patients, respectively. Moreover, IGF1R deficiency in mice reduced tumor growth, proliferation, inflammation and vascularization, and increased apoptosis after tumor heterotopic transplantation. Following induction of lung metastasis, IGF1R-deficient lungs also demonstrated a reduced tumor burden, and decreased expression of tumor progression markers, p-IGF1R and p-ERK1/2. Additionally, IGF1R-deficient lungs showed increased apoptosis and diminished proliferation, vascularization, EMT and fibrosis, along with attenuated inflammation and immunosuppression. Accordingly, IGF1R deficiency decreased expression of p-IGF1R in blood vessels, fibroblasts, tumor-associated macrophages and FOXP3⁺ tumor-infiltrating lymphocytes. Our results demonstrate that IGF1R promotes metastatic tumor initiation and progression in lung TME. Furthermore, our research indicates that IGF1R could be a potential biomarker for early prediction of drug response and clinical evolution in NSCLC patients.

Cell-penetrating peptides containing the progesterone receptor polyproline domain inhibits EGF signaling and cell proliferation in lung cancer cells

Non-small cell lung cancer (NSCLC) accounts for the majority (80-85%) of all lung cancers. All current available treatments have limited efficacy. The epidermal growth factor receptor (EGFR) plays a critical role in the development and progression of NSCLC, with high EGFR expression associated with increased cell proliferation and poor prognosis. Thus, interfering with EGFR signaling has been shown to effectively reduce cell proliferation and help in the treatment of NSCLC. We previously demonstrated that the progesterone receptor (PR) contains a polyproline domain (PPD) that directly interacts with Src homology 3 (SH3) domain-containing molecules and expression of PR-PPD peptides inhibits NSCLC cell proliferation. In this study, we investigated whether the introduction of PR-PPD by cell-penetrating peptides (CPPs) could inhibit EGF-induced cell proliferation in NSCLC cells. PR-PPD was attached to a cancer-specific CPP, Buforin2 (BR2), to help deliver the PR-PPD into NSCLC cells. Interestingly, addition of BR2-2xPPD peptides containing two PR-PPD repeats was more effective in inhibiting NSCLC proliferation and significantly reduced EGF-induced phosphorylation of Erk1/2. BR2-2xPPD treatment induced cell cycle arrest by inhibiting the expression of cyclin D1 and CDK2 genes in EGFR-wild type A549 cells. Furthermore, the combination treatment of EGFR-tyrosine kinase inhibitors (TKIs), including Gefitinib or Erlotinib, with BR2-2xPPD peptides further suppressed the growth of NSCLC PC9 cells harboring EGFR mutations as compared to EGFR-TKIs treatment alone. Importantly, BR2-2xPPD peptides mediated growth inhibition in acquired Gefitinib- and Erlotinib- resistant lung adenocarcinoma cells. Our data suggests that PR-PPD is the minimal protein domain sufficient to inhibit NSCLC cell growth and has the potential to be developed as a novel NSCLC therapeutic agent.

Delineation of gastric tumors with activated ERK/MAPK signaling cascades for the development of targeted therapeutics

The ERK/MAPK signaling pathway is activated in various cancers including gastric cancer. Targeting the ERK/MAPK/MEK pathway has been considered as a promising strategy for cancer therapy. However, MEK inhibition leads to a series of resistance mechanisms due to mutations in MEK, elevated expression of RAS or RAF proteins and activation of the associated signaling pathways. In the present study, ERK/MAPK pathway specific gene signatures were identified to be highly activated in intestinal subtype gastric tumors. Inhibition of ERK/MAPK pathway with the inhibitor PD98059 in gastric cancer cell lines by in vitro signaling pathway and genome-wide expression profiling revealed the associated signaling pathways. Functional genomic investigation of the ERK/MAPK regulated genes reveals the association of ERK/MAPK pathway with E2F, Myc, SOX-2, TGF-β, OCT4 and Notch pathways in gastric cancer cells. Of these, E2F, Myc and SOX-2 pathways are activated in intestinal subtype gastric tumors and TGF-β, OCT4, Notch pathways are activated in diffuse subtype gastric tumors. Further, the mutational load of gastric tumors was found to have association and correlation with the activation pattern of ERK/MAPK pathways across gastric tumors. ERK/MAPK activation was also found to represent the EBV and MSI activated subtypes of gastric tumors. Identification of potent drug candidates inhibiting the ERK/MAPK and associated pathways would pave a way for developing the targeted therapeutics for a subset of gastric tumors with activated ERK/MAPK signaling cascade.

Endoderm development requires centrioles to restrain p53-mediated apoptosis in the absence of ERK activity

Centrioles comprise the heart of centrosomes, microtubule-organizing centers. To study the function of centrioles in lung and gut development, we genetically disrupted centrioles throughout the mouse endoderm. Surprisingly, removing centrioles from the endoderm did not disrupt intestinal growth or development but blocked lung branching. In the lung, acentriolar SOX2-expressing airway epithelial cells apoptosed. Loss of centrioles activated p53, and removing p53 restored survival of SOX2-expressing cells, lung branching, and mouse viability. To investigate how endodermal p53 activation specifically killed acentriolar SOX2-expressing cells, we assessed ERK, a prosurvival cue. ERK was active throughout the intestine and in the distal lung buds, correlating with tolerance to centriole loss. Pharmacologically inhibiting ERK activated apoptosis in acentriolar cells, revealing that ERK activity protects acentriolar cells from apoptosis. Therefore, centrioles are largely dispensable for endodermal growth and the spatial distribution of ERK activity in the endoderm shapes the developmental consequences of centriolar defects and p53 activation.

NKX2-1 controls lung cancer progression by inducing DUSP6 to dampen ERK activity

The RAS→RAF→MEK→ERK pathway is hyperactivated in the majority of human lung adenocarcinoma (LUAD). However, the initial activating mutations induce homeostatic feedback mechanisms that limit ERK activity. How ERK activation reaches the tumor-promoting levels that overcome the feedback and drive malignant progression is unclear. We show here that the lung lineage transcription factor NKX2-1 suppresses ERK activity. In human tissue samples and cell lines, xenografts, and genetic mouse models, NKX2-1 induces the ERK phosphatase DUSP6, which inactivates ERK. In tumor cells from late-stage LUAD with silenced NKX2-1, re-introduction of NKX2-1 induces DUSP6 and inhibits tumor growth and metastasis. We show that DUSP6 is necessary for NKX2-1-mediated inhibition of tumor progression in vivo and that DUSP6 expression is sufficient to inhibit RAS-driven LUAD. Our results indicate that NKX2-1 silencing, and thereby DUSP6 downregulation, is a mechanism by which early LUAD can unleash ERK hyperactivation for tumor progression.

Apatinib inhibits the growth of small cell lung cancer via a mechanism mediated by VEGF, PI3K/Akt and Ki-67/CD31

This study aimed to investigate the anti‐tumour effect of apatinib on extensive‐stage small cell lung cancer (SCLC) and elucidate the associated mechanisms. NCI‐H345 cells were selected as model cells because of high expression of vascular endothelial growth factor (VEGF), VEGF receptor 2 (VEGFR2) and phosphorylated‐VEGFR2 (pVEGFR2). Cells were exposed to recombinant human VEGF (rhVEGF) and apatinib. Cells were then divided into eight groups, namely, control, rhVEGF, apatinib, rhVEGF+apatinib, serum‐free medium (SM), SM+rhVEGF, SM+apatinib and SM+rhVEGF+apatinib. In comparison with the control group, cell proliferation in vitro in apatinib, SM, SM+apatinib and SM+rhVEGF+apatinib groups was inhibited, particularly in SM+apatinib group. The effect of apatinib on tumour growth in vivo was investigated using a mouse xenograft tumour model. In comparison with the control group, tumour sizes were reduced in apatinib‐treated group on days 34 and 37. Immunohistochemical and immunofluorescence staining revealed that VEGF, pVEGFR2, PI3K, AKT, p‐ERK1/2, Ki‐67 and CD31 in the tumour cells of apatinib‐treated group were downregulated compared with control group. Haematoxylin and eosin staining revealed that apatinib promoted the necrosis of SCLC cells in vivo. In conclusion, apatinib inhibited the growth of SCLC cells by downregulating the expression of VEGF, pVEGFR2, p‐PI3K, p‐AKT, p‐ERK1/2, Ki‐67 and CD31.

Microfluidic Single-Cell Proteomics Assay Chip: Lung Cancer Cell Line Case Study

Cancer is a dynamic disease involving constant changes. With these changes, cancer cells become heterogeneous, resulting in varying sensitivity to chemotherapy. The heterogeneity of cancer cells plays a key role in chemotherapy resistance and cancer recurrence. Therefore, for effective treatment, cancer cells need to be analyzed at the single-cell level by monitoring various proteins and investigating their heterogeneity. We propose a microfluidic chip for a single-cell proteomics assay that is capable of analyzing complex cellular signaling systems to reveal the heterogeneity of cancer cells. The single-cell assay chip comprises (i) microchambers (n = 1376) for manipulating single cancer cells, (ii) micropumps for rapid single-cell lysis, and (iii) barcode immunosensors for detecting nine different secretory and intracellular proteins to reveal the correlation among cancer-related proteins. Using this chip, the single-cell proteomics of a lung cancer cell line, which may be easily masked in bulk analysis, were evaluated. By comparing changes in the level of protein secretion and heterogeneity in response to combinations of four anti-cancer drugs, this study suggests a new method for selecting the best combination of anti-cancer drugs. Subsequent preclinical and clinical trials should enable this platform to become applicable for patient-customized therapies.

Exosome Released FZD10 Increases Ki-67 Expression via Phospho-ERK1/2 in Colorectal and Gastric Cancer

Frizzled (FZD) proteins are primary receptors for Wnt signaling that activates the mitogen-activated protein kinase (MAPK) pathways. Dysfunction of Wnt signals with consequently abnormal activation of MAPK3 pathways was found in colorectal cancer (CRC) and gastric cancer (GC). Upregulation of FZD10 protein, localized in the exosomes isolated from plasma of CRC and GC patients, was associated with a poor prognosis. Herein, the expression levels of circulating FZD10 were found to be strongly correlated to their expression levels in the corresponding tissues in CRC and GC patients. Bioinformatic prediction revealed a link between FZD10 and Ki-67 through MAPK3. In both CRC and GC tissues, pERK1/2 levels were significantly increased at more advanced disease stages, and pERK1/2 and Ki-67 were correlated. Silencing of FZD10 in CRC and GC cells resulted in a significant reduction of pERK1/2 and Ki-67 expression, while subsequent treatment with exogenous exosomes partially restored their expression levels. The strong correlation between the expression of Ki-67 in tissues and of FZD10 in exosomes suggests that the exosome-delivered FZD10 may be a promising novel prognostic and diagnostic biomarker for CRC and GC.

DUSP7 inhibits cervical cancer progression by inactivating the RAS pathway

To determine the differentially expressed proteins (DEPs) between paired samples of cervical cancer (CC) and paracancerous tissue by quantitative proteomics and to examine the effects of DUSP7 expression on the tumorigenesis and progression of CC. Proteomic profiles of three paired samples of CC and paracancerous tissue were quantitatively analysed to identify DEPs. The relationship between DEP expression and patient clinicopathological characteristics and prognosis was evaluated. The effects of the selected DEPs on CC progression were examined in SIHA cells. A total of 129 DEPs were found. Western blot and immunohistochemistry (IHC) staining analyses confirmed the results from quantitative proteomic analysis showing that the selected DEP, HRAS, P-ERK1/2, and PLD1 levels were increased, whereas the DUSP7 level was decreased in CC tissue compared with the paired normal paracancerous tissues. The IHC results from the CC TMA analysis showed that the decreased expression of DUSP7 (p = 0.045 and 0.044) was significantly associated with a tumour size >2 cm and parametrial infiltration. In addition, the decreased expression of DUSP7 and increased expression of p-ERK1/2 were adversely related to patient relapse (p = 0.003 and 0.001) and survival (p = 0.034 and 0.006). The expression of HRAS and p-ERK1/2 was decreased in DUSP7-SIHA cells compared with NC-SIHA cells (p = 0.0003 and 0.0026). Biological functions in vitro, including invasion, migration and proliferation and tumour formation in vivo were decreased in DUSP7-SIHA cells (all p < 0.05) but increased in shDUSP7-SIHA cells (all p < 0.05). DUSP7 inhibits cervical cancer progression by inactivating the RAS pathway.

Inhibiting Eukaryotic Elongation Factor 2 Kinase: An Update on Pharmacological Small-Molecule Compounds in Cancer

Eukaryotic elongation factor 2 kinase (eEF2K), a member of the atypical protein kinase family of alpha-kinases, is well-known as a negative regulator of protein synthesis by phosphorylating eEF2. Notably, eEF2K functions as a key regulator of several cellular processes, leading to tumorigenesis. To date, some small-molecule compounds have been reported as potential eEF2K inhibitors in cancer drug discovery. However, an ideal targeted drug design still faces huge challenges. Alternatively, other design strategies, such as repurposed drugs, dual-target drugs, and drug combination strategies, provide insights into the improvement of cancer treatment. Here, we summarize the crucial eEF2K-modulating pathways in cancer, including AMPK, REDD1, and Src. Moreover, we discuss the inhibition of eEF2K with single-target inhibitors, repurposed drugs, dual-target inhibitors, drug combination strategies, and other emerging technologies for therapeutic purposes. Together, these inspiring findings provide insights into a promising strategy for inhibiting eEF2K with small-molecule compounds to improve potential cancer therapy.

Anti-Metastatic Effects of Lupeol via the Inhibition of MAPK/ERK Pathway in Lung Cancer

BACKGROUND AND OBJECTIVE

ERK pathway is one of the most crucial pathways in lung cancer metastasis. Targeting its pathway is decisive in lung cancer research. Thus, this study demonstrated for the first time for significant and selective anti-metastatic effects of lupeol against lung cancer A549 cells via perturbations in the ERK signaling pathway.

MATERIALS AND METHODS

Human protein targets of lupeol were predicted in silico. Migration and cytotoxicity assays were carried out in vitro. Expression levels of proteins Erk1/2 and pErk1/2 were ensured using Enzyme- Linked Immunosorbent Assay (ELISA). Semi-quantitative RT-PCR technique was used to estimate changes in crucial mesenchymal marker gene expression levels of N-cadherin and vimentin.

RESULTS

Lupeol was found to target ERK and MEK proteins effectively. Despite having no cytotoxic effects, lupeol also significantly inhibited cell migration in A549 cells with decreased expression of the pErk1/2 protein along with N-cadherin and vimentin genes.

CONCLUSION

Lupeol inhibits cell migration, showed no cytotoxic effects on A549 cells, decreased pErk1/2 and EMT gene expression. Thus, it can serve as a potential ERK pathway inhibitor in lung cancer therapeutics.

Tripartite motif protein 11 (TRIM11), an oncogene for human lung cancer via the DUSP6-mediated ERK1/2 signaling pathway

Evidence suggests that Tripartite Motif Containing 11 (TRIM11) has pro-tumor activity in human non-small cell lung cancer (NSCLC). However, the roles and underlying mechanisms of TRIM11 in NSCLC have not yet been fully elucidated. In this work, human lung cancer cell lines (A549, H446, and H1975) were transfected with siRNA or lentiviruses to knockdown or overexpress TRIM11 and dual-specificity phosphatase 6 (DUSP6). The cell tumor response was assessed by determining the rate of proliferation, apoptosis, the uptake of 2-[N-(7-nitrobenz-2-oxa-1, 3-diaxol-4-yl) amino]-2-deoxyglucose (2-NBDG), and the secretion of lactic acid (LD). Dominant-negative (dn)-MEK1 was used to block the ERK1/2 pathway. The mechanism was investigated by assessing the protein levels of pyruvate kinase isozymes M2 (PKM2) and DUSP6, as well as the activation of ERK1/2 pathway. Our data confirmed the anti-cancer effect of siTRIM11 in human lung cancer by demonstrating inhibition of cancer cell proliferation, induction of apoptosis, prevention of 2-NBDG uptake, suppression of LD production, and prevention of lung cancer cell (A549) tumorigenicity in nude mice. The underlying mechanism involved the up-regulation of DUSP6 and the inhibition of ERK1/2 activity. Overexpression of TRIM11 induced tumorigenesis of NSCLC in vitro, and the activation of ERK1/2 was significantly reversed by DUSP6 overexpression or additional dn-MEK1 treatment. Interestingly, we confirmed TRIM11 as a deubiquitinase that regulated DUSP6 accumulation, indicating that lung cancer progression is regulated via the DUSP6-ERK1/2 pathway. In conclusion, TRIM11 is an oncogene in NSCLC, likely through the DUSP6-mediated ERK1/2 signaling pathway.

Racially Disparate Expression of mTOR/ERK-1/2 Allied Proteins in Cancer

Recent studies revealed that ethnic differences in mechanistic target of rapamycin (mTOR) and extracellular signal-regulated kinase (ERK-1/2) signaling pathways might be associated with the development and progression of different human malignancies. The African American (AA) population has an increased rate of cancer incidence and mortality compared to the Caucasian American (CA) population. Although the socioeconomic differences across different ethnic groups contribute to the disparity in developing different cancers, recent scientific evidence indicates the association of molecular and genetic variations in racial disparities of different human malignancies. The mTOR and ERK-1/2 signaling pathways are one of the well-known oncogenic signaling mechanisms that regulate diverse molecular and phenotypic aspects of normal as well as cancer cells in response to different external or internal stimuli. To date, very few studies have been carried out to explore the significance of racial disparity with abnormal mTOR and ERK-1/2 kinase signaling pathways, which may contribute to the development of aggressive human cancers. In this review, we discuss the differential regulation of mTOR and ERK-1/2 kinase signaling pathways across different ethnic groups, especially between AA and CA populations. Notably, we observed that key signaling proteins associated with mTOR and ERK-1/2 pathway including transforming growth factor-beta (TGF-β), Akt, and VEGFR showed racially disparate expression in cancer patients. Overall, this review article encompasses the significance of racially disparate signaling molecules related to mTOR/ERK1/2 and their potential in developing tailor-made anti-cancer therapies.

Cytoplasmic phosphorylated ERK1/2 expression in patients with melanoma is associated with tumor stage and metastasis

Melanoma is the cause of most deaths from skin cancer. The extracellular signal-regulated kinase 1/2 (ERK1/2) pathway has been reported to participate in progression of melanoma in fair skinned populations. ERK1/2 is found in both the cytoplasm and nucleus of cells, and phosphorylated ERK1/2 has been implicated in tumor progression. We investigated the relation between melanoma progression and expression of cytoplasmic and nuclear phosphorylated ERK1/2. We examined 34 surgically resected melanomas and investigated their clinicopathologic characteristics. We found immunostaining of phosphorylated ERK1/2 in all melanomas and faint staining in benign nevi. We found expression of cytoplasmic phosphorylated ERK1/2 in most melanomas; however, nuclear phosphorylated ERK1/2 expression was found in only five melanomas. Expression of cytoplasmic phosphorylated ERK1/2 was related to the tumor stage in melanoma. Nine of 10 cases of distant metastasis were positive for cytoplasmic phosphorylated ERK1/2. Our findings suggest that phosphorylated ERK1/2 expression is relevant to clinical pathology and that in melanoma patients, phosphorylated ERK1/2 expression is found in both the cytoplasm and nucleus. Our findings suggest that cytoplasmic phosphorylated ERK1/2 participates in progression of melanoma and that it could be a useful target for clinical treatment of melanoma.

Contribution of miRNAs, tRNAs and tRFs to Aberrant Signaling and Translation Deregulation in Lung Cancer

Simple Summary

The profiles of miRNAs, tRNA-derived fragments and tRNAs from lung cancer biopsy specimens indicate involvement of gene networks that modulate signaling and translation initiation. The current study highlights the important role of several regulatory small non-coding RNAs in aberrant signaling and translation deregulation in lung cancer.

Abstract

Transcriptomics profiles of miRNAs, tRNAs or tRFs are used as biomarkers, after separate examination of several cancer cell lines, blood samples or biopsies. However, the possible contribution of all three profiles on oncogenic signaling and translation as a net regulatory effect, is under investigation. The present analysis of miRNAs and tRFs from lung cancer biopsies indicated putative targets, which belong to gene networks involved in cell proliferation, transcription and translation regulation. In addition, we observed differential expression of specific tRNAs along with several tRNA-related genes with possible involvement in carcinogenesis. Transfection of lung adenocarcinoma cells with two identified tRFs and subsequent NGS analysis indicated gene targets that mediate signaling and translation regulation. Broader analysis of all major signaling and translation factors in several biopsy specimens revealed a crosstalk between the PI3K/AKT and MAPK pathways and downstream activation of eIF4E and eEF2. Subsequent polysome profile analysis and 48S pre-initiation reconstitution experiments showed increased global translation rates and indicated that aberrant expression patterns of translation initiation factors could contribute to elevated protein synthesis. Overall, our results outline the modulatory effects that possibly correlate the expression of important regulatory non-coding RNAs with aberrant signaling and translation deregulation in lung cancer.

ERK phosphorylation as a marker of RAS activity and its prognostic value in non-small cell lung cancer

BACKGROUND

Deregulated signal transduction pathways play a key role in development, progression and therapeutic resistance of non-small cell lung cancers (NSCLC). The purpose of this study is to assess the downstream markers of two well-characterized pathways and to correlate them with clinical outcome.

DESIGN

670 patients with metastatic NSCLC were prospectively enrolled in a comprehensive biomarker profiling program at a single center from 2012 to 2016. Phosphorylation of extracellular signal-regulated kinase (p-ERK), and protein kinase B (p-AKT) was assessed by standardized immunohistochemistry. Product of scores for quantity and quality of staining were calculated (immunoreactive score, 0-9). Somatic mutations of Kirsten rat sarcoma viral oncogene homolog [KRAS], epithelial growth factor receptor [EGFR], v-Raf murine sarcoma viral oncogene homolog B [BRAF] and phosphatidylinositol 3-kinase [PIK3CA]) were detected by Sanger (2012-03/2015) and amplicon NGS (04/2015-02/2016). Patients enrolled during the first year (2012) were used as discovery cohort. Patients enrolled from 2013 to 02/2016 were used as validation cohort. Clinical data were retrieved from the electronic medical records and were analyzed retrospectively.

RESULTS

Using a discovery cohort, we identified an immunoreactive score of p-ERK ≥3 to be prognostically relevant. The validation cohort confirmed that higher levels of p-ERK correlated with worse overall survival (OS) and higher proportion of RAS mutations. Multivariate analysis including established risk factors such EGFR, ALK or ROS mutations and metastatic disease showed a trend of a detrimental effect of high p-ERK on OS (HR 1.23, CI 0.94-1.59, p = 0.131 for p-ERK immunoreactive score ≥3) and time to treatment failure after first-line therapy in the validation cohort. Phosphorylated AKT did not correlate with clinical outcome.

CONCLUSION

While serving as a prognosticator in univariate analysis, highly phosphorylated ERK does not convey a significant prognostic effect for OS in the presence of other prognostic factors. Phosphorylated ERK indicates a higher activity of RAS in advanced NSCLC.

Indirect co-culture of lung carcinoma cells with hyperthermia-treated mesenchymal stem cells influences tumor spheroid growth in a collagen-based 3-dimensional microfluidic model

BACKGROUND

Mesenchymal stem cells (MSCs) have paradoxically been reported to exert either pro- or anti-tumor effects in vitro. Hyperthermia, in combination with chemotherapy, has tumor-inhibiting effects; however, its role, together with MSCs, so far is not well understood. Furthermore, a lot of research is conducted using conventional 2-dimensional in vitro models that do not mimic the actual tumor microenvironment.

AIM

In light of this fact, an indirect method of co-culturing human amniotic membrane-derived MSCs (AMMSCs) with collagen-encapsulated human lung carcinoma cells (A549) was performed using a 3-dimensional (3D) tumor-on-chip device.

METHODS

The conditioned medium of AMMSCs (AMMSC-CM) or heat-treated AMMSCs (heat-AMMSC-CM) was utilized to create indirect co-culture conditions. Tumor spheroid growth characterization, immunocytochemistry and cytotoxicity assays, and anti-cancer peptide (P1) screening were performed to determine the effects of the conditioned medium.

RESULTS

The A549 cells cultured inside the 3D microfluidic chip developed into multicellular tumor spheroids over five days of culture. The AMMSC-CM, contrary to previous reports claiming its tumor-inhibiting potential, led to significant proliferation of tumor spheroids. Heat-AMMSC-CM led to reductions in both spheroid diameter and cell proliferation. The medium containing the P1 peptide was found to be the least cytotoxic to tumor spheroids in co-culture compared with the monoculture and heat-co-culture groups.

CONCLUSIONS

Hyperthermia, in combination with the anticancer peptide, exhibited highest cytotoxic effects. This study highlights the growing importance of 3D microfluidic tumor models for testing stem-cell-based and other anti-cancer therapies.

Independent Validation of Early-Stage Non-Small Cell Lung Cancer Prognostic Scores Incorporating Epigenetic and Transcriptional Biomarkers With Gene-Gene Interactions and Main Effects

BACKGROUND

DNA methylation and gene expression are promising biomarkers of various cancers, including non-small cell lung cancer (NSCLC). Besides the main effects of biomarkers, the progression of complex diseases is also influenced by gene-gene (G×G) interactions.

RESEARCH QUESTION

Would screening the functional capacity of biomarkers on the basis of main effects or interactions, using multiomics data, improve the accuracy of cancer prognosis?

STUDY DESIGN AND METHODS

Biomarker screening and model validation were used to construct and validate a prognostic prediction model. NSCLC prognosis-associated biomarkers were identified on the basis of either their main effects or interactions with two types of omics data. A prognostic score incorporating epigenetic and transcriptional biomarkers, as well as clinical information, was independently validated.

RESULTS

Twenty-six pairs of biomarkers with G×G interactions and two biomarkers with main effects were significantly associated with NSCLC survival. Compared with a model using clinical information only, the accuracy of the epigenetic and transcriptional biomarker-based prognostic model, measured by area under the receiver operating characteristic curve (AUC), increased by 35.38% (95% CI, 27.09%-42.17%; P = 5.10 × 10-17) and 34.85% (95% CI, 26.33%-41.87%; P = 2.52 × 10-18) for 3- and 5-year survival, respectively, which exhibited a superior predictive ability for NSCLC survival (AUC3 year, 0.88 [95% CI, 0.83-0.93]; and AUC5 year, 0.89 [95% CI, 0.83-0.93]) in an independent Cancer Genome Atlas population. G×G interactions contributed a 65.2% and 91.3% increase in prediction accuracy for 3- and 5-year survival, respectively.

INTERPRETATION

The integration of epigenetic and transcriptional biomarkers with main effects and G×G interactions significantly improves the accuracy of prognostic prediction of early-stage NSCLC survival.

Beneficial effect of fluoxetine on anti-tumor progression on hepatocellular carcinoma and non-small cell lung cancer bearing animal model

Fluoxetine, an antidepressant, has been indicated to elicit anti-cancer response in hepatocellular carcinoma (HCC) and non-small cell lung cancer (NSCLC) in vitro. However, anticancer effect and mechanism of fluoxetine in HCC and NSCLC in vivo still needs to be elucidated. In this study, we showed anticancer efficacy and inhibitory mechanism of fluoxetine on the tumor progression of HCC and NSCLC in vivo. Tumor growth was significantly inhibited with fluoxetine treatment in HCC and NSCLC in vivo. Fluoxetine obviously decreased expression of cell proliferative, anti-apoptotic, invasion-associated proteins including Cyclin-D1, survivin, vascular endothelial growth factor (VEGF), matrix metallopeptidase 9 (MMP-9) and urokinase-type plasminogen activator (uPA). Importantly, fluoxetine diminished the phosphorylation of NF-κB p65 which recognized as one of the critical transcription factors in tumor progression. Inhibition of AKT or extracellular signal-regulated kinases (ERK) phosphorylation was linked to NF-κB inactivation in NSCLC or HCC in vitro. Furthermore, expression of AKT or ERK phosphorylation was effectively attenuated by fluoxetine treatment in NSCLC or HCC in vivo. In addition, fluoxetine also triggered extrinsic/intrinsic apoptotic signaling by activating caspase-3, -8, and -9 in HCC and NSCLC. Our findings suggest that fluoxetine may represent as a promising adjuvant for patients with HCC or NSCLC. In conclude, the results also suggested the blockage of AKT/NF-κB or ERK/NF-κB activation and the induction of apoptosis are associated with fluoxetine-inhibited tumor progression of HCC or NSCLC in vivo.

The ubiquitin system: orchestrating cellular signals in non-small-cell lung cancer

The ubiquitin system, known as a common feature in eukaryotes, participates in multiple cellular processes, such as signal transduction, cell-cycle progression, receptor trafficking and endocytosis, and even the immune response. In lung cancer, evidence has revealed that aberrant events in ubiquitin-mediated processes can cause a variety of pathological outcomes including tumorigenesis and metastasis. Likewise, ubiquitination on the core components contributing to the activity of cell signaling controls bio-signal turnover and cell final destination. Given this, inhibitors targeting the ubiquitin system have been developed for lung cancer therapies and have shown great prospects for clinical application. However, the exact biological effects and physiological role of the drugs used in lung cancer therapies are still not clearly elucidated, which might seriously impede the progress of treatment. In this work, we summarize current research advances in cell signal regulation processes mediated through the ubiquitin system during the development of lung cancer, with the hope of improving the therapeutic effects by means of aiming at efficient targets.

SFRP1 in Skin Tumor Initiation and Cancer Stem Cell Regulation with Potential Implications in Epithelial Cancers

Wnt signaling is involved in the regulation of cancer stem cells (CSCs); however, the molecular mechanism involved is still obscure. SFRP1, a Wnt inhibitor, is downregulated in various human cancers; however, its role in tumor initiation and CSC regulation remains unexplored. Here, we used a skin carcinogenesis model, which showed early tumor initiation in Sfrp1^−/− (Sfrp1 knockout) mice and increased tumorigenic potential of Sfrp1^−/− CSCs. Expression profiling on Sfrp1^−/− CSCs showed upregulation of genes involved in epithelial to mesenchymal transition, stemness, proliferation, and metastasis. Further, SOX-2 and SFRP1 expression was validated in human skin cutaneous squamous cell carcinoma, head and neck squamous cell carcinoma, and breast cancer. The data showed downregulation of SFRP1 and upregulation of SOX-2, establishing their inverse correlation. Importantly, we broadly uncover an inverse correlation of SFRP1 and SOX-2 in epithelial cancers that may be used as a potential prognostic marker in the management of cancer.

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Loss of Sfrp1 accelerates murine skin tumor initiation and SCC progression

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Sfrp1 loss enhances in vivo tumorigenic potential of murine skin CSCs

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We found enhanced EMT and Sox-2 in Sfrp1^−/− murine skin SCC

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Sfrp1 and Sox-2 are inversely correlated in multiple human epithelial cancers

K-Ras-ERK1/2 accelerates lung cancer cell development via mediating H3K18ac through the MDM2-GCN5-SIRT7 axis

Context: H3^K18ac is linked to gene expression and DNA damage. Nevertheless, whether H3^K18ac participates in regulating Ras-ERK1/2-affected lung cancer cell phenotypes remains unclear. Objective: We explored the effects of H3^K18ac on Ras-ERK1/2-affected lung cancer cell phenotypes. Material and methods: NCI-H2126 cells were transfected with, pEGFP-K-Ras^WT and pEGFP-K-Ras^G12V/T35S plasmids for 48 h, and transfection with pEGFP-N1 served as a blank control. Then H3^K18ac and AKT and ERK1/2 pathways-associated factors were examined. Different amounts of the H3^K18Q (0.5, 1, and 2 μg) plasmids and Ras^G12V/T35S were co-transfected into NCI-H2126 cells, cell viability, cell colonies and migration were analyzed for exploring the biological functions of H3^K18ac in NCI-H2126 cells. The ERK1/2 pathway downstream factors were detected by RT-PCR and ChIP assays. The regulatory functions of SIRT7, GCN5 and MDM2 in Ras-ERK1/2-regulated H3^K18ac expression were finally uncovered. Results: Ras^G12V/T35S transfection decreased the expression of H3^K18ac about 2.5 times compared with the pEGFP-N1 transfection group, and activated ERK1/2 and AKT pathways. Moreover, H3^K18ac reduced cell viability, colonies, migration, and altered ERK1/2 downstream transcription in NCI-H2126 cells. Additionally, SIRT7 knockdown increased H3^K18ac expression and repressed cell viability, migration and the percentage of cells in S phase by about 50% compared to the control group, as well as changed ERK1/2 downstream factor expression. Besides, Ras-ERK1/2 decreased H3^K18ac was linked to MDM2-regulated GCN5 degradation. Conclusion: These observations disclosed that Ras-ERK1/2 promoted the development of lung cancer via decreasing H3^K18ac through MDM2-mediated GCN5 degradation. These findings might provide a new therapeutic strategy for lung cancer.

Clarithromycin synergizes with cisplatin to inhibit ovarian cancer growth in vitro and in vivo

Background

Cisplatin-based chemotherapy is the first-line treatment for ovarian cancer. However, acquired resistance to cisplatin treatment often occurs in epithelial ovarian cancer, and effective and practical methods for overcoming this obstacle are urgently needed. The study aimed to demonstrate the synergistic effect of clarithromycin (CAM) with cisplatin to inhibit ovarian carcinoma cells growth in vitro and in vivo.

Results

We performed CCK-8 assay to detect apoptosis rates in response to CAM alone or in combination with cisplatin, which were further confirmed by Annexin V and PI staining methods and western blotting. Mechanistically, CAM could reduce endogenous antioxidant enzyme expression and increase the levels of reactive oxygen species (ROS) to augment the cytotoxic effect of cisplatin. Meanwhile, a tumor xenograft model in athymic BALB/c-nude mice demonstrated that CAM combined with cisplatin resulted in reduced tumor growth and weight compared with cisplatin alone.

Conclusion

Collectively, our results indicate that CAM works synergistically with cisplatin to inhibit ovarian cancer cell growth, which may be manipulated by a ROS-mediated mechanism that enhances cisplatin therapy, and offers a novel strategy for overcoming cisplatin therapy resistance.

Quadruplex-forming oligonucleotide targeted to the VEGF promoter inhibits growth of non-small cell lung cancer cells

BACKGROUND

Vascular endothelial growth factor (VEGF) is commonly overexpressed in a variety of tumor types including lung cancer. As a key regulator of angiogenesis, it promotes tumor survival, growth, and metastasis through the activation of the downstream protein kinase B (AKT) and extracellular signal-regulated kinase (ERK 1/2) activation. The VEGF promoter contains a 36 bp guanine-rich sequence (VEGFq) which is capable of forming quadruplex (four-stranded) DNA. This sequence has been implicated in the down-regulation of both basal and inducible VEGF expression and represents an ideal target for inhibition of VEGF expression.

RESULTS

Our experiments demonstrate sequence-specific interaction between a G-rich quadruplex-forming oligonucleotide encoding a portion of the VEGFq sequence and its double stranded target sequence, suggesting that this G-rich oligonucleotide binds specifically to its complementary C-rich sequence in the genomic VEGF promoter by strand invasion. We show that treatment of A549 non-small lung cancer cells (NSCLC) with this oligonucleotide results in decreased VEGF expression and growth inhibition. The VEGFq oligonucleotide inhibits proliferation and invasion by decreasing VEGF mRNA/protein expression and subsequent ERK 1/2 and AKT activation. Furthermore, the VEGFq oligonucleotide is abundantly taken into cells, localized in the cytoplasm/nucleus, inherently stable in serum and intracellularly, and has no effect on non-transformed cells. Suppression of VEGF expression induces cytoplasmic accumulation of autophagic vacuoles and increased expression of LC3B, suggesting that VEGFq may induce autophagic cell death.

CONCLUSION

Our data strongly suggest that the G-rich VEGFq oligonucleotide binds specifically to the C-rich strand of the genomic VEGF promoter, via strand invasion, stabilizing the quadruplex structure formed by the genomic G-rich sequence, resulting in transcriptional inhibition. Strand invading oligonucleotides represent a new approach to specifically inhibit VEGF expression that avoids many of the problems which have plagued the therapeutic use of oligonucleotides. This is a novel approach to specific inhibition of gene expression.

Silicosis and lung cancer: current perspectives

"Silica" refers to crystalline particles formed by the combination of silicon with oxygen. Inhalation of silica particles promotes the development of pulmonary fibrosis that over prolonged periods increases the risk of lung cancer. The International Agency for Research on Cancer (IARC) classified crystalline silica as a human carcinogen in 1997. This categorization was questioned due to 1) the absence of dose-response findings, 2) the presence of confounding variables that complicated interpretation of the data and 3) potential selection bias for compensated silicosis. Yet, recent epidemiologic studies strongly support the conclusion that silica exposure increases the risk of lung cancer in humans independent of confounding factors including cigarette smoke. Based on this evidence, the US Occupational Safety and Health Administration (OSHA) lowered the occupational exposure limit for crystalline silica from 0.1 to 0.05 mg/m³ in 2013. Further supporting the human epidemiologic data, murine models show that chronic silicosis is associated with an increased risk of lung cancer. In animals, the initial inflammation induced by silica exposure is followed by the development of an immunosuppressive microenvironment that supports the growth of lung tumors. This work will review our current knowledge of silica-associated lung cancers, highlighting how recent mechanistic insights support the use of cutting-edge approaches to diagnose and treat silica-related lung cancer.

JNK1/2 and ERK1/2 provides vital clues about tumor recurrence and survival in hepatocellular carcinoma patients

AIM

To explore JNK1/2 and ERK1/2 activation in hepatocellular carcinoma (HCC) patients.

PATIENTS & METHODS

Phosphorylated-JNK1/2 and -ERK1/2 (p-JNK1/2 and p-ERK1/2) expressions were determined and analyzed in 104 unique HCC tissue specimens.

RESULTS

Expression of p-JNK1/2 and p-ERK1/2 was not correlated with clinicopathological characteristics. High p-JNK1/2 and low p-ERK1/2 expressions predicated significantly lower tumor recurrence for HCC patients. However, HCC patients with low p-JNK1/2 and high p-ERK1/2 had higher tumor recurrence. Moreover, p-JNK1/2 positively, but p-ERK1/2 negatively, associated with overall survival (OS) and recurrence-free survival (RFS) in HCC patients. In addition, HCC patients with simultaneous low p-JNK1/2 and high p-ERK1/2 had poorer OS and RFS. On the contrary, patients with high p-JNK1/2 and low p-ERK1/2 presented better OS and RFS.

CONCLUSION

HCC patients with low p-JNK1/2 and high p-ERK1/2 either independently or simultaneously, had significantly higher tumor recurrence and worse OS.

Oncogene-induced regulation of microRNA expression: Implications for cancer initiation, progression and therapy

A plethora of tumours have characteristic oncogenic mutations which are the main causes of malignant transformation, exerting their effects through multiple signalling pathways. Downstream of such pathways, microRNAs are small non-coding RNAs that negatively regulate gene expression, assisting or antagonizing oncogenic signalling. The differential expression of microRNAs in cancer is well-documented and is considered a fundamental aspect of tumourigenesis. While data mapping the interaction between oncogenic lesions and microRNAs are accruing, we provide particular cases of such interaction. Except for notable, well-studied examples of microRNAs regulated by oncogenes, we examine the effect of this relationship in regard to tumour initiation, progression, metastasis and ultimately, its implications for the development of new therapeutics.

Mechanisms of Aquaporin-Facilitated Cancer Invasion and Metastasis

Cancer is a leading cause of death worldwide, and its incidence is rising with numbers expected to increase 70% in the next two decades. The fact that current mainline treatments for cancer patients are accompanied by debilitating side effects prompts a growing demand for new therapies that not only inhibit growth and proliferation of cancer cells, but also control invasion and metastasis. One class of targets gaining international attention is the aquaporins, a family of membrane-spanning water channels with diverse physiological functions and extensive tissue-specific distributions in humans. Aquaporins−1,−2,−3,−4,−5,−8, and−9 have been linked to roles in cancer invasion, and metastasis, but their mechanisms of action remain to be fully defined. Aquaporins are implicated in the metastatic cascade in processes of angiogenesis, cellular dissociation, migration, and invasion. Cancer invasion and metastasis are proposed to be potentiated by aquaporins in boosting tumor angiogenesis, enhancing cell volume regulation, regulating cell-cell and cell-matrix adhesions, interacting with actin cytoskeleton, regulating proteases and extracellular-matrix degrading molecules, contributing to the regulation of epithelial-mesenchymal transitions, and interacting with signaling pathways enabling motility and invasion. Pharmacological modulators of aquaporin channels are being identified and tested for therapeutic potential, including compounds derived from loop diuretics, metal-containing organic compounds, plant natural products, and other small molecules. Further studies on aquaporin-dependent functions in cancer metastasis are needed to define the differential contributions of different classes of aquaporin channels to regulation of fluid balance, cell volume, small solute transport, signal transduction, their possible relevance as rate limiting steps, and potential values as therapeutic targets for invasion and metastasis.

Histology-dependent prognostic role of pERK and p53 protein levels in early-stage non-small cell lung cancer

Lung tumors represent a major health problem. In early stage NSCLC tumors, surgical resection is the preferred treatment, but 30-55% of patients will relapse within 5 years after surgery. Thus, the identification of prognostic biomarkers in early stage NSCLC patients, especially those which are therapeutically addressable, is crucial to enhance survival of these patients. We determined the immunohistochemistry expression of key proteins involved in tumorigenesis and oncogenic signaling, p53, EGFR, pAKT and pERK, and correlated their expression level to clinicopathological characteristics and patient outcome. We found EGFR expression is higher in the squamous cell carcinomas than in adenocarcinomas (p=0.043), and that nuclear p53 staining correlated with lower differentiated squamous tumors (p=0.034). Regarding the prognostic potential of the expression of these proteins, high pERK levels proved to be an independent prognostic factor for overall (p<0.001) and progression-free survival (p<0.001) in adenocarcinoma patients, but not in those from the squamous histology, and high p53 nuclear levels were identified as independent prognostic factor for progression-free survival (p=0.031) only in squamous cell carcinoma patients. We propose a role as early prognostic biomarkers for pERK protein levels in adenocarcinoma, and for nuclear p53 levels in squamous cell lung carcinoma. The determination of these potential biomarkers in the adequate histologic context may predict the outcome of early stage NSCLC patients, and may offer a therapeutic opportunity to enhance survival of these patients.

Suppression of Cell Growth, Migration and Drug Resistance by Ethanolic Extract of Antrodia cinnamomea in Human Lung Cancer A549 Cells and C57BL/6J Allograft Tumor Model

The purpose of this study was to investigate the inhibitory activities of ethanolic extracts from Antrodia cinnamomea (EEAC) on lung cancer. Cell proliferation and cell cycle distribution were analyzed using (3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay and flow cytometry, respectively. Wound-healing assay, Western blotting, and a murine tumor model were separately used to examine cell migration, protein expression, and tumor repression. Our results showed that EEAC induced cell cycle arrest at the G0/G1 phase resulting decreased cell viability in A549 cells. Moreover, EEAC up-regulated the growth-suppressing proteins, adenosine 5′-monophosphate-activated protein kinase (AMPK), p21 and p27, but down-regulated the growth-promoting proteins, protein kinase B (Akt), mammalian tarfet of rapamycin (mTOR), extracellular signal-regulating kinase 1/2 (ERK1/2), retinoblastoma protein (Rb), cyclin E, and cyclin D1. EEAC also inhibited A549 cell migration and reduced expression of gelatinases. In addition, our data showed that tumor growth was suppressed after treatment with EEAC in a murine allograft tumor model. Some bioactive compounds from EEAC, such as cordycepin and zhankuic acid A, were demonstrated to reduce the protein expressions of matrix metalloproteinase (MMP)-9 and cyclin D1 in A549 cells. Furthermore, EEAC enhanced chemosensitivity of A549 to paclitaxel by reducing the protein levels of caveolin-1. Our data suggests that EEAC has the potential to be an adjuvant medicine for the treatment of lung cancer.

Oncolytic influenza virus infection restores immunocompetence of lung tumor-associated alveolar macrophages

Non-small-cell lung cancer (NSCLC) is the most frequent type of lung cancer and demonstrates high resistance to radiation and chemotherapy. These tumors evade immune system detection by promoting an immunosuppressive tumor microenvironment. Genetic analysis has revealed oncogenic activation of the Ras/Raf/MEK/ERK signaling pathway to be a hallmark of NSCLCs, which promotes influenza A virus (IAV) infection and replication in these cells. Thus, we aimed to unravel the oncolytic properties of IAV infection against NSCLCs in an immunocompetent model in vivo. Using Raf-BxB transgenic mice that spontaneously develop NSCLCs, we demonstrated that infection with low-pathogenic IAV leads to rapid and efficient oncolysis, eliminating 70% of the initial tumor mass. Interestingly, IAV infection of Raf-BxB mice caused a functional reversion of immunosuppressed tumor-associated lung macrophages into a M1-like pro-inflammatory active phenotype that additionally supported virus-induced oncolysis of cancer cells. Altogether, our data demonstrate for the first time in an immunocompetent in vivo model that oncolytic IAV infection is capable of restoring and redirecting immune cell functions within the tumor microenvironment of NSCLCs.

Implications of the HDAC6-ERK1 feed-forward loop in immunotherapy

The oncogene HDAC6 controls numerous cell processes that are related to tumorigenesis and metastasis, and has recently arisen as a target to treat malignancies. The ERK cascade is a classic pathway driving oncogenesis, and the components of this pathway are either highly mutated in cancers or are vital in cancer's pathological activity. The interactions between these important components of tumor proliferation have been examined, and our research has demonstrated that they regulate each other as evidenced by different posttranslational modifications. Preclinical evidence also supports clinical trials cotargeting these two pathways, which may provide better efficacy than single treatment. Furthermore, HDAC6 and ERK both participate in the regulation of T cell maturation and may have implications on the functions of immune cells. This leads to the possibility of connecting HDAC6 and ERK to immunotherapy. In this review, we summarize the published studies about the interaction of HDAC6 and ERK cascade and their relationship to cancers. We also include the association of HDAC6 and ERK to immune system and discuss the plausibility of linking these to immunotherapy.

Comparative Network Analysis of Patients with Non-Small Cell Lung Cancer and Smokers for Representing Potential Therapeutic Targets

Cigarette smoking is the leading cause of lung cancer worldwide. In this study, we evaluated the serum autoantibody (AAb) repertoires of non-small cell lung cancer (NSCLC) patients and smokers (SM), leading to the identification of overactivated pathways and hubs involved in the pathogenesis of NSCLC. Surface- and solution-phase biopanning were performed on immunoglobulin G purified from the sera of NSCLC and SM groups. In total, 20 NSCLC- and 12 SM-specific peptides were detected, which were used to generate NSCLC and SM protein datasets. NSCLC- and SM-related proteins were visualized using STRING and Gephi, and their modules were analyzed using Enrichr. By integrating the overrepresented pathways such as pathways in cancer, epithelial growth factor receptor, c-Met, interleukin-4 (IL-4) and IL-6 signaling pathways, along with a set of proteins (e.g. phospholipase D (PLD), IL-4 receptor, IL-17 receptor, laminins, collagens, and mucins) into the PLD pathway and inflammatory cytokines network as the most critical events in both groups, two super networks were made to elucidate new aspects of NSCLC pathogenesis and to determine the influence of cigarette smoking on tumour formation. Taken together, assessment of the AAb repertoires using a systems biology approach can delineate the hidden events involved in various disorders.

MicroRNA-133a Inhibits Proliferation of Gastric Cancer Cells by Downregulating ERBB2 Expression

Gastric cancer is the fourth most common type of cancer and the second highest leading cause of cancer-related deaths worldwide. It has already been established that miR-133a is involved in gastric cancer. In this study, we investigated the molecular mechanisms by which miR-133a inhibits the proliferation of gastric cancer cells. We analyzed the proliferative capacity of human gastric cancer cells SNU-1 using an MTT assay. Cell apoptosis was determined using flow cytometry. The expression levels of ERBB2, p-ERK1/2, and p-AKT in SNU-1 cells were determined using Western blot analysis. To confirm that ERBB2 is a direct target of miR-133a, a luciferase reporter assay was performed. Results showed that miR-133a overexpression inhibited SNU-1 cell proliferation and increased apoptosis. ERBB2 was a direct target of miR-133a, and it was negatively regulated by miR-133a. Interestingly, ERBB2 silencing has a similar impact to miR-133a overexpression, in that it significantly induced apoptosis and inhibited ERK and AKT activation. Our study showed that miR-133a inhibits the proliferation of gastric cancer cells by downregulating the expression of ERBB2 and its downstream signaling molecules p-ERK1/2 and p-AKT. Therefore, miR-133a might be used as a therapeutic target for treating gastric cancer.

p53 loss does not permit escape from BrafV600E-induced senescence in a mouse model of lung cancer

Lung cancer arises through the acquisition of a number of genetic lesions, with a preponderance of activating mutations in the canonical mitogen-activated protein kinase (MAPK) cascade (RTK-RAS-RAF-MEK). Braf^V600E expression induces benign lung adenomas that fail to progress to adenocarcinoma because of oncogene-induced senescence (OIS). Braf^V600E expression, coupled with simultaneous p53 ablation, permits bypass of senescence and progression to lung adenocarcinoma. However, spontaneous human tumors sustain mutations in a temporally separated manner. Here, we use a mouse lung cancer model where oncogene activation (Braf^V600E expression) and tumor suppressor loss (p53 ablation) are independently controlled through the actions of Flp and Cre recombinase, respectively. We show that p53 loss before OIS is permissive for the transition from lung adenoma to adenocarcinoma. In contrast, p53 loss after senescence is established fails to enable escape from senescence and disease progression. This study demonstrates that Braf^V600E induced senescence is irreversible in vivo and suggests that therapy-induced senescence would halt further tumor progression.

Combination of celecoxib and PD184161 exerts synergistic inhibitory effects on gallbladder cancer cell proliferation

Cyclooxygenase-2 (COX-2) and extracellular signal-regulated kinase 1/2 (ERK1/2) may serve as potential targets in various types of cancer; however, the roles of these proteins in gallbladder carcinoma (GBC) have not been reported previously. In the present study, the expression levels of COX-2 and phospho (p)-ERK1/2 in GBC were examined and the biological activities of celecoxib and PD184161 (specific inhibitors of COX-2 and p-ERK1/2, respectively) on the proliferation, cell cycle and apoptosis of the GBC-SD and NOZ human GBC cell lines were evaluated by a series of in vitro and in vivo studies. COX-2 and p-ERK1/2 protein expression levels were found to be significantly elevated in GBC tissues as well as in GBC-SD and NOZ cells. Treatments with celecoxib and PD184161 significantly inhibited GBC-SD and NOZ cell growth in a concentration-dependent manner, and their combination produced a synergistic inhibitory effect. In addition, celecoxib and PD184161 significantly inhibited tumor growth in xenograft nude mice. Celecoxib treatment led to G1 arrest via the upregulation of p21 and p27 expression in GBC-SD and NOZ cells, whereas PD184161 did not affect cell cycle distribution. The combination of celecoxib and PD184161 was able to promote cell apoptosis by triggering a collapse of mitochondrial membrane potential and activating caspase-3-mediated apoptosis. In conclusion, COX-2 and p-ERK1/2 protein may serve as potential targets for GBC chemotherapy, and the combination of celecoxib and PD184161 could significantly inhibit GBC cell growth, induce cell G1 arrest and trigger cell apoptosis of GBC cells.

Pharmacology and clinical application of compound Qifang Weitong formula

Previous studies on the pharmacology and clinical application of compound Qifang Weitong formula have shown that it can ameliorate inflammation-induced gastric mucosal injury, protect the gastric mucosa, improve the structure of regenerated tissue, promote gastric ulcer healing and regeneration, and inhibit gastric ulcer recurrence. Therefore, this formula can be used to treat gastric ulcer, chronic atrophic gastritis (CAG), CAG with atypical hyperplasia, irritable bowel syndrome and functional dyspepsia.