Emerging lung cancer therapeutic targets based on the pathogenesis of bone metastases

Overview of Ca2+ signaling in lung cancer progression and metastatic lung cancer with bone metastasis

Intracellular Ca²⁺ ions that are thought to be one of the most important second messengers for cellular signaling, have a substantial diversity of roles in regulating a plethora of fundamental cellular physiology such as gene expression, cell division, cell motility and apoptosis. It has been suggestive of the Ca²⁺ signaling-dependent cellular processes to be tightly regulated by the numerous types of Ca²⁺ channels, pumps, exchangers and sensing receptors. Consequently, dysregulated Ca²⁺ homeostasis leads to a series of events connected to elevated malignant phenotypes including uncontrolled proliferation, migration, invasion and metastasis, all of which are frequently observed in advanced stage lung cancer cells. The incidence of bone metastasis in patients with advanced stage lung cancer is estimated in a range of 30% to 40%, bringing about a significant negative impact on both morbidity and survival. This review dissects and summarizes the important roles of Ca²⁺ signaling transduction in contributing to lung cancer progression, and address the question: if and how Ca²⁺ signaling might have been engaged in metastatic lung cancer with bone metastasis, thereby potentially providing the multifaceted and promising solutions for therapeutic intervention.

Targeting NF-κB mediated cell signaling pathway and inflammatory mediators by 1,2-diazole in A549 cells in vitro

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1,2-Diazole suppresses TNF-α induced MMP-2 expression.

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1,2-Diazole abrogate NF-κB activation and regulate cytokines.

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It exhibits potent in vitro anticancer effect against A549 cells.

Lung cancer is the leading cause of cancer deaths globally. The objective of this study was to investigate the effect of 1,2-diazole (pyrazole) as an anti-cancer drug on human non-small cell lung carcinoma A549 cells. We attempt to examine the expression level of pro-inflammatory proteins such as TNF-α, NF-κB-p65, MMP-2 and E-Cadherin which are commonly associated with an inflammatory response in epithelial cells and apoptosis in A549 cells. The LPS-induced cytokines and inflammatory mediators include TNF-α, IL-6, iNOS and COX-2 levels in A549 cells and the effect of pyrazole was studied. The present study reveals that, pyrazole inhibits A549 cells by suppressing TNF-α induced MMP-2 expression, thereby inhibiting the nuclear translocation of NF-κB-p65. Pyrazole significantly up-regulate the E-cadherin level and down-regulated MMP-2 expression that could probably preventing A549 cancer cells to invade. The study further substantiated the anti-cancer property of pyrazole by regulating the above mentioned level of LPS-induced cytokines and inflammatory mediators. The observations of the present study open a possibility for the development of an effective therapeutic agent that targets inflammatory and signaling pathway mediators to challenge human non-small cell lung carcinoma.

Nurse-Delivered Brief Behavioral Treatment for Insomnia in Lung Cancer Survivors: A Pilot RCT

Objective/Background: Insomnia occurs in 50 to 80% of lung cancer survivors. Cognitive behavioral therapy is the standard treatment for insomnia (CBTI); however, treatment length and lack of psychologists trained in CBTI limits access. Brief Behavioral Treatment for Insomnia (BBTI), a nurse-delivered modified CBTI, is proposed. This feasibility pilot study sought to compare the BBTI intervention to attention control Healthy Eating Program (HEP) for insomnia in lung cancer survivors. Participants: The participants comprised adults, 21 years of age or older with insomnia and stage I/II non-small cell lung cancer, more than 6 weeks from surgery and living in Western NY. Methods: Participants (n = 40) were randomly assigned to an experimental (BBTI) or attention control condition (Healthy Eating Program). Thirty participants completed the study. Results: Participants were 66 years of age (± 7.6; range 53-82), 40% (n = 16) male, 87.5% (n = 35) Caucasian, 50% (n = 20) married, BMI 27.7 (± 5.8), and 12% (n = 5) never smokers. Baseline sleep diary sleep efficiency, ISI and other baseline covariates were balanced between the groups. Sleep efficiency improved ≥85% in BBTI group (p = .02), but not in HEP control group (p = 1.00). Mean ISI for BBTI and attention control were 6.40 ± 4.98 and 14.10 ± 4.48 (p = .001) respectively. In addition, BBTI group mean total FACT-L score improved by 6.66 points from baseline while HEP group score worsened (p = .049). Conclusions: BBTI is a practical, evidence-based, clinically relevant intervention that improved sleep and quality of life in lung cancer survivors with insomnia. Additional research to evaluate efficacy, duration, and implementation strategies are essential.

Discovery of a novel protein kinase C activator from Croton tiglium for inhibition of non-small cell lung cancer

BACKGROUND

The incidence of non-small cell lung cancer (NSCLC) accounts for approximately 85-90% of lung cancer, which has been shown to be challenging for treatment owing to poorly understanding of pathological mechanisms. Natural products serve as a source of almost all pharmaceutical preparations or offer guidance for those chemicals that have entered clinical trials, especially in NSCLC.

PURPOSE

We investigated the effect of B10G5, a natural products isolated from the Croton tiglium, in human non-small cell lung canceras as a protein kinase C (PKC) activator.

METHODS

The cell viability assay was evaluated by the MTT assay. The apoptosis and cell cycle distribution were assessed by flow cytometry. Reactive oxygen species (ROS) production was determined by using the fluorescent probe DCFDA. Cell migration ability of H1975 cells was analyzed by using the wound healing assay. The inhibiting effect of B10G5 against the phosphorylation level of the substrate by PKCs was assessed by using homogeneous time-resolved fluorescence (HTRF) technology. The correlation between PKCs and overall survival (OS) of Lung Adenocarcinoma (LUAD) patients was analysis by TCGA portal. The binding mode between B10G5 and the PKC isoforms was explored by molecular docking. Protein expression was detected by western blotting analysis.

RESULTS

B10G5 suppressed cell proliferation and colony formation, as well as migration ability of NSCLC cells, without significant toxic effect on normal lung cells. B10G5 induced the cell apoptosis through the development of PARP cleavage, which is evidenced by means of the production of mitochondrial ROS. In addition, the B10G5 inhibitory effect was also related to the cell cycle arrest at G2/M phase. Mechanistically, molecular modelling technology suggested that the potential target of B10G5 was associated with PKC family. In vitro PKC kinase assay indicated that B10G5 effectively activated the PKC activity. Western blotting data revealed that B10G5 upregulated PKC to activate PKC-mediated RAF/MEK/ERK pathway.

CONCLUSION

Our results showed that B10G5, a naturally occurring phorbol ester, considered to be a potential and a valuable therapeutic chemical in the treatment of NSCLC.

Gossypol Inhibits Non-small Cell Lung Cancer Cells Proliferation by Targeting EGFRL858R/T790M

Background: Overexpression of epidermal growth factor receptor (EGFR) has been reported to be implicated in the pathogenesis of non-small cell lung cancer (NSCLC). Several EGFR inhibitors have been used in clinical treatment of NSCLC, but the emergence of EGFR^L858R/T790M resistant mutation has reduced the efficacy of the clinical used EGFR inhibitors. There is an urgent need to develop novel EGFR^L858R/T790M inhibitors for better NSCLC treatment.

Methods: By screening a natural product library, we have identified gossypol as a novel potent inhibitor targeting EGFR^L858R/T790M. The activity of gossypol on NSCLC cells was evaluated by cell proliferation, cell apoptosis and cell migration assays. Kinase activity inhibition assay and molecular docking were used to study the inhibition mechanism of gossypol to EGFR^L858R/T790M. Western blotting was performed to study the molecular mechanism of gossypol inhibiting the downstream pathways of EGFR.

Results: Gossypol inhibited the cell proliferation and cell migration of NSCLC cells, and induced caspase-dependent cell apoptosis of NSCLC cells by upregulating the expression of pro-apoptotic protein BAD. Molecular docking revealed that gossypol could bind to the kinase domain of EGFR^L858R/T790M with good binding affinity through hydrogen bonds and hydrophobic interactions. Gossypol inhibited the kinase activity of EGFR^L858R/T790M with EC₅₀ of 150.1 nM. Western blotting analysis demonstrated that gossypol inhibited the phosphorylation of EGFR and its downstream signal pathways in a dose-dependent manner.

Conclusion: Gossypol inhibited cell proliferation and induced apoptosis of NSCLC cells by targeting EGFR^L858R/T790M. Our findings provided a basis for developing novel EGFR^L858R/T790M inhibitors for treatment of NSCLC.

Sclerotic Bone Metastasis in Pulmonary Adenocarcinoma

Pulmonary adenocarcinoma is one of the major types of lung cancers in which metastasis is very common and it accounts approximately to one-third of all primary pulmonary cancers. Although a minority of patients with lung cancer are asymptomatic, which gets usually detected in routine chest radiography, most of the patients present with some symptoms. Lung cancer metastasis may occur virtually in every organ system. Patients with non-small-cell lung cancer commonly have extrathoracic metastases to the adrenal glands, liver, brain, bones, and lymph nodes at presentation. Approximately one-third of patients with lung cancer will present with symptoms related to extrathoracic spread. Metastasis to the bone is not uncommon in lung cancer; however, osteoblastic bone metastasis is very rare. Here we present a 30-year-old female diagnosed to have pulmonary adenocarcinoma with multiple sclerotic bony lesions in the vertebra.

Osteoactivin (GPNMB) ectodomain protein promotes growth and invasive behavior of human lung cancer cells

The potential application of GPNMB/OA as a therapeutic target for lung cancer will require a greater understanding of the impact of GPNMB/OA ectodomain (ECD) protein shedding into tumor tissues. Thus, in this work we characterized GPNMB/OA expression and extent of shedding of its ECD protein while evaluating the impact on lung cancer progression using three non-small cell lung cancer (NSCLC) cell lines: A549, SK-MES-1 and calu-6. We observed a direct correlation (R² = 0.89) between GPNMB/OA expression on NSCLC cells and the extent of GPNMB/OA ECD protein shedding. Meanwhile, siRNA-mediated knockdown of GPNMB/OA in cancer cells significantly reduced GPNMB/OA ECD protein shedding, migration, invasion and adhesion to extracellular matrix materials. Also, exogenous treatment of cancer cells (expressing low GPNMB/OA) with recombinant GPNMB/OA protein (rOA) significantly facilitated cell invasion and migration, but the effects of rOA was negated by inclusion of a selective RGD peptide. Further studies in athymic (nu/nu) mice-bearing calu-6 showed that intratumoral supplementation with rOA effectively facilitated in vivo tumor growth as characterized by a high number of proliferating cells (Ki67 staining) coupled with a low number of apoptotic cells. Taken together, our results accentuate the relevance of GPNMB/OA ECD protein shedding to progression of lung cancer. Thus, strategies that suppress GPNMB/OA expression on lung cancer cells as well as negate shedding of GPNMB/OA ECD protein are worthy of consideration in lung cancer therapeutics.

Chinese medicine Bu-Fei decoction attenuates epithelial-mesenchymal transition of non-small cell lung cancer via inhibition of transforming growth factor β1 signaling pathway in vitro and in vivo

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional Chinese medicine Bu-Fei decoction (BFD) has been utilized to treat patients with Qi deficiency for decades, with the advantages of invigorating vital energy, clearing heat-toxin and moistening lung, etc. According to previous clinical experience and trials, BFD has been found to indeed improve life quality of lung cancer patients and prolong survival time. Nevertheless, little is known on its potential mechanisms so far. Being regarded as a pivotal cytokine in the tumor microenvironment, transforming growth factor β (TGF-β) stands out as a robust regulator of epithelial-mesenchymal transition (EMT), which is closely linked to tumor progression.

AIM OF THE STUDY

The present study was designed to explore whether BFD antagonized EMT via blocking TGF-β1-induced signaling pathway, and then help contribute to create a relatively steady microenvironment for confining lung cancer.

MATERIALS AND METHODS

This experiment was performed in lung adenocarcinoma A549 cells both in vitro and in vivo. In detail, the influences mediated by TGF-β1 alone or in combination with different concentrations of BFD on migration were detected by wound healing and transwell assays, and the effects of BFD on cell viability were determined by cell counting kit-8 (CCK-8) assay. TGF-β1, EMT relevant proteins and genes were evaluated by western blotting, confocal microscopy, quantitative real-time polymerase chain reaction (qRT-PCR), immunohistochemistry (IHC) and enzyme-linked immuno sorbent assay (ELISA). Female BALB/C nude mice were subcutaneously implanted A549 cells and given BFD by gavage twice daily for 28 days. The tumor volume was monitored every 4 days to draw growth curve. The tumor weight, expression levels of EMT-related protein in tumor tissues and TGF-β1 serum level were evaluated, respectively.

RESULTS

BFD only exerted minor effects on A549 cell proliferation and this was in accordance with the in vivo result, which showed that the tumor growth and weight were not be restrained by BFD administration. However, the data elucidated that BFD could dose-dependently suppress EMT induced by TGF-β1 in vitro via attenuating canonical Smad signaling pathway. In the A549 xenograft mouse model, BFD also inhibited protein markers that are associated with EMT and TGF-β1 secretion into serum.

CONCLUSIONS

Based on these above data, the conclusion could be put forward that BFD probably attenuated TGF-β1 mediated EMT in A549 cells via decreasing canonical Smad signaling pathway both in vitro and in vivo, which may help restrain the malignant phenotype induced by TGF-β1 in A549 cells to some extent.

Significance of Trask protein interactions in brain metastatic cohorts of lung cancers

A class of adhesion protein that occurs in the membrane with both extracellular and intracellular domain and play vital role in maintaining multicellularity is TRASK, also called CUB-domain containing protein1, CD318 (CDCP1). Specifically, in the current study, documented aggressive grades of lung cancers and distant metastatic tissues were examined for protein interactions of Trask and compared with lung cancer variants in situ. The intracellular domain of Trask has the ability to undergo tyrosine phosphorylation and thereafter undergo increased genomic expression, as well as interact with cytoskeletal proteins in the cell periphery and other local signal transduction machinery to induce invadopodia formation and distant metastasis. We incorporated proximity ligation assay to examine protein interactions of Trask in metastatic lung cancer tissues and compare with advanced and low-grade lung cancers restricted to the primary site of origins. Here, we provide direct evidence that activated Trask, which is a phosphorylated form, binds with cytoskeletal proteins actin and spectrin. These interactions were not seen in locally growing lung cancer and cancer in situ. These interactions may be responsible for invadopodia formation and breaking free from a multicellular environment. Functional studies demonstrated interaction between Trask and the STOCs Orai1 and Stim1. Calcium release from internal stores was highest in metastatic lung cancers, suggesting this mechanism as an initial stimulus for the cells to respond chaotically to external growth factor stimulation, especially in aggressive metastatic variants of lung cancers. Recently, inhibitors of STOCs have been identified, and preclinical evidence may be obtained whether these drugs may be of benefit in preventing the deadly consequences of lung cancer.

Metastatic tumors to the jaws and mouth

Metastatic dissemination to the oral cavity is rare and is usually the evidence of a wide spread disease with an average survival rate of 7 months. In almost a quarter of the cases, oral metastasis was found to be the first indication of an occult malignancy at a distant site. Metastatic lesions can be found anywhere in the oral cavity, however, the jaw bones with the molar area is the most frequently involved site. In the oral soft tissues, the gingiva is the most common site, suggesting the possible role of inflammation in the attraction of metastatic deposits. The most common primary malignancies presenting oral metastases were the lung, kidney, liver, and prostate for men, and breast, female genital organs, kidney, and colo-rectum for women. Most patients with jawbone metastasis complain of swelling, pain, and paresthesia. An exophytic lesion is the most common clinical presentation of metastatic lesions in the oral soft tissues. Early lesions, mainly those located in the gingiva, may resemble a hyperplastic or reactive lesion. Once a lesion is recognized as metastasis, the primary tumor site should be identified following clinical, radiological and histopathological investigations. If standardized diagnostic workup fails to detect the site of origin, then the term carcinoma of unknown primary is applied. Personalized medicine tools such as tissue-of-origin assays should be applied, either by immunohistochemical testing or by molecular-profiling methods as these may lead to a more favorable outcome.