A novel report of apoptosis in human lung carcinoma cells using selective agonist of D2-like dopamine receptors: a new approach for the treatment of human non-small cell lung cancer

Advancements in Oncoproteomics Technologies: Treading toward Translation into Clinical Practice

Proteomics continues to forge significant strides in the discovery of essential biological processes, uncovering valuable information on the identity, global protein abundance, protein modifications, proteoform levels, and signal transduction pathways. Cancer is a complicated and heterogeneous disease, and the onset and progression involve multiple dysregulated proteoforms and their downstream signaling pathways. These are modulated by various factors such as molecular, genetic, tissue, cellular, ethnic/racial, socioeconomic status, environmental, and demographic differences that vary with time. The knowledge of cancer has improved the treatment and clinical management; however, the survival rates have not increased significantly, and cancer remains a major cause of mortality. Oncoproteomics studies help to develop and validate proteomics technologies for routine application in clinical laboratories for (1) diagnostic and prognostic categorization of cancer, (2) real-time monitoring of treatment, (3) assessing drug efficacy and toxicity, (4) therapeutic modulations based on the changes with prognosis and drug resistance, and (5) personalized medication. Investigation of tumor-specific proteomic profiles in conjunction with healthy controls provides crucial information in mechanistic studies on tumorigenesis, metastasis, and drug resistance. This review provides an overview of proteomics technologies that assist the discovery of novel drug targets, biomarkers for early detection, surveillance, prognosis, drug monitoring, and tailoring therapy to the cancer patient. The information gained from such technologies has drastically improved cancer research. We further provide exemplars from recent oncoproteomics applications in the discovery of biomarkers in various cancers, drug discovery, and clinical treatment. Overall, the future of oncoproteomics holds enormous potential for translating technologies from the bench to the bedside.

Anticancer efficacy of endo- and exogenous potent ligands acting at dopaminergic receptor-expressing cancer cells

Cancer is one of the most common and dreaded diseases affecting the vastness of society. Unfortunately, still some people die especially when cancer is not diagnosed and thus caught early enough. On the other hand, using available chemo- or radiotherapy may result in serious side effects. Therefore, cancer-specific medications seem to be the most desired and safe therapy. Knowing that some cancers are characterized by overexpression of specific receptors on the cell surface, target-mediated drugs could serve as a unique and effective form of therapy. In line with this, recently dopaminergic receptors were presented important in cancer therapy as several dopaminergic ligands revealed their efficacy in tumor growth reduction as well as in apoptosis mediation. Unfortunately, the indication of whether DA receptor agonists or antagonists are the best choices in cancer treatment is quite difficult, since both of them may exert either pro- or anticancer effects. In this review, we analyze the therapeutic efficacy of compounds, both of exogenous and endogenous origin, targeting dopaminergic receptor-expressing cancers.

Expression, correlation, and prognostic significance of different nicotinic acetylcholine receptors, programed death ligand 1, and dopamine receptor D2 in lung adenocarcinoma

Objective

The objective of this study is to evaluate the expression of different nicotinic acetylcholine receptors (nAChRs), programmed death ligand-1 (PD-L1), and dopamine receptor D2 (DRD2) as prognostic factors in lung cancer and any correlation among them. Since all of the above genes are typically upregulated in response to smoking, we hypothesized that a correlation might exist between DRD2, PD-L1, and nAChR expression in NSCLC patients with a smoking history and a prediction model may be developed to assess the clinical outcome.

Methods

We retrospectively analyzed samples from 46 patients with primary lung adenocarcinoma who underwent surgical resection at Mayo Clinic Rochester from June 2000 to October 2008. The expression of PD-L1, DRD2, CHRNA5, CHRNA7, and CHRNA9 were analyzed by quantitative PCR and correlated amongst themselves and with age, stage and grade, smoking status, overall survival (OS), and relapse-free survival (RFS).

Results

Only PD-L1 showed a statistically significant increase in expression in patients older than 65. All the above genes showed higher expression in stage IIIB than IIIA, but none reached statistical significance. Interestingly, we did not observe significant differences among never, former, and current smokers, but patients with pack years greater than 30 showed significantly higher expression of CHRNA9. We observed a strong positive correlation between PD-L1/DRD2, PD-L1/CHRNA5, and CHRNA5/CHRNA7 and a weak positive correlation between DRD2/CHRNA5 and DRD2/CHRNA7. Older age was independently associated with poor OS, whereas lower CHRNA7 expression was independently associated with better OS.

Conclusions

We observed strong positive correlations among PD-L1, DRD2, and some of the nAChRs. We investigated their prognostic significance in lung cancer patients and found CHRNA7 to be an independent prognostic factor. Overall, the results obtained from this preliminary study warrant a large cohort-based analysis that may ultimately lead to potential patient-specific stratification biomarkers predicting cancer-treatment outcomes.

Anti-Tumor and Anti-Invasive Effects of ONC201 on Ovarian Cancer Cells and a Transgenic Mouse Model of Serous Ovarian Cancer

ONC201 is a promising first-in-class small molecule that has been reported to have anti-neoplastic activity in various types of cancer through activation of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) as well as activation of mitochondrial caseinolytic protease P (ClpP). The present study was to explore the anti-tumor potential effect of ONC201 in ovarian cancer cell lines and in a transgenic mouse model of high grade serous ovarian cancer under obese (high fat diet) and lean (low fat diet) conditions. ONC201 significantly suppressed cell proliferation, induced arrest in G1 phase, and increased cellular stress and apoptosis, accompanied by dual inhibition of the AKT/mTOR/S6 and MAPK pathways in OC cells. ONC201 also resulted in inhibition of adhesion and invasion via epithelial–mesenchymal transition and reduction of VEGF expression. Pre-treatment with the anti-oxidant, N-acetylcysteine (NAC), reversed the ONC201-induced oxidative stress response, and prevented ONC201-reduced VEGF and cell invasion by regulating epithelial–mesenchymal transition protein expression. Knockdown of ClpP in ovarian cancer cells reduced ONC201 mediated the anti-tumor activity and cellular stress. Diet-induced obesity accelerated ovarian tumor growth in the KpB mouse model. ONC201 significantly suppressed tumor growth, and decreased serum VEGF production in obese and lean mice, leading to a decrease in tumoral expression of Ki-67, VEGF and phosphorylation of p42/44 and S6 and an increase in ClpP and DRD5, as assessed by immunohistochemistry. These results suggest that ONC201 may be a promising therapeutic agent to be explored in future clinical trials in high-grade serous ovarian cancer.

A success targeted nano delivery to lung cancer cells with multi-walled carbon nanotubes conjugated to bromocriptine

In this research, a new nano drug-based multi-walled carbon nanotubes (MWCNTs) was prepared and evaluated qualitatively. Bromocriptine (BRC) was conjugated to functionalized carbon nanotubes. Then, the CHNS, FT-IR, SEM, and RAMAN tests for characterization of the conjugated drug were done. The nanofluid-containing nano-drug was evaluated on lung cancer cells (A549 & QU-DB) and MRC5 by MTT and flow cytometry tests. Then, the gene expression studies of dopamine receptor genes were done before and after nano-drug treatment. After that, a western blotting test was carried out for further investigation of dopamine receptors protein production. Finally, Bax and Bcl-2 secretion were measured by the ELISA method in cells affected by MWCNTs-BRC Nf compared to untreated cells. The results showed that the nano-drug had a significant lethal effect on cancer cells, while it had no toxicity on MRC5. Also, the nano-drug could significantly induce apoptosis in lung cancer cells at a lower dose compared to the drug alone. In this study, a targeted nano-drug delivery system was designed, and its performance was evaluated based on neurotransmitter pathways, and the results showed that it may be useful in the treatment of lung cancer. However, additional studies on animal models are underway.

Studies in lung cancer cytokine proteomics: a review

INTRODUCTION

Proteins are molecules that have role in the progression of the diseases. Proteomics is a tool that can play an effective role in identifying diagnostic and therapeutic biomarkers for lung cancer. Cytokines are proteins that play a decisive role in activating body's immune system in lung cancer. They can increase the growth of the tumor (oncogenic cytokines) or limit tumor growth (anti-tumor cytokines) by regulating related signaling pathways such as proliferation, growth, metastasis, and apoptosis.

AREAS COVERED

In the present study, a total of 223 papers including 196 research papers and 27 review papers, extracted from PubMed and Scopus and published from 1997 to present, are reviewed. The most important involved-cytokines in lung cancer including TNF-α, IFN- γ, TGF-β, VEGF and interleukins such as IL-6, IL-17, IL-8, IL-10, IL-22, IL-1β and IL-18 are introduced. Also, the pathological and biological role of such cytokines in cancer signaling pathways is explained.

EXPERT OPINION

In lung cancer, the cytokine expression changes under the physiological conditions of the immune system, and inflammatory cytokines are associated with the progression of lung cancer. Therefore, the cytokine expression profile can be used in the diagnosis, prognosis, prediction of therapeutic responses, and survival of patients with lung cancer.

DRD1 downregulation contributes to mechanical stretch-induced lung endothelial barrier dysfunction

Rationale: The lung-protective effects of dopamine and its role in the pathology of ventilator-induced lung injury (VILI) are emerging. However, the underlying mechanisms are still largely unknown.

Objective: To investigate the contribution of dopamine receptor dysregulation in the pathogenesis of VILI and therapeutic potential of dopamine D1 receptor (DRD1) agonist in VILI.

Methods: The role of dopamine receptors in mechanical stretch-induced endothelial barrier dysfunction and lung injury was studied in DRD1 knockout mice, in isolated mouse lung vascular endothelial cells (MLVECs), and in lung samples from patients who underwent pulmonary lobectomy with mechanical ventilation for different time periods.

Measurements and Main Results: DRD1 was downregulated in both surgical patients and mice exposed to mechanical ventilation. Prophylactic administration of dopamine or DRD1 agonist attenuated mechanical stretch-induced lung endothelial barrier dysfunction and lung injury. By contrast, pulmonary knockdown or global knockout of DRD1 exacerbated these effects. Prophylactic administration of dopamine attenuated mechanical stretch-induced α-tubulin deacetylation and subsequent endothelial hyperpermeability through DRD1 signaling. We identified that cyclic stretch-induced glycogen-synthase-kinase-3β activation led to phosphorylation and activation of histone deacetylase 6 (HDAC6), which resulted in deacetylation of α-tubulin. Upon activation, DRD1 signaling attenuated mechanical stretch-induced α-tubulin deacetylation and subsequent lung endothelial barrier dysfunction through cAMP/exchange protein activated by cAMP (EPAC)-mediated inactivation of HDAC6.

Conclusions: This work identifies a novel protective role for DRD1 against mechanical stretch-induced lung endothelial barrier dysfunction and lung injury. Further study of the mechanisms involving DRD1 in the regulation of microtubule stability and interference with DRD1/cAMP/EPAC/HDAC6 signaling may provide insight into therapeutic approaches for VILI.

The Current Recommended Drugs and Strategies for the Treatment of Coronavirus Disease (COVID-19)

BACKGROUND

The coronavirus 2019 (COVID-19) has been known as a pandemic disease by the World Health Organization (WHO) worldwide. The drugs currently used for treatment of COVID-19 are often selected and tested based on their effectiveness in other diseases such as influenza and AIDS and their major identified targets are viral protease, host cell produced protease, viral RNA polymerase, and the interaction site of viral protein with host cell receptors. Until now, there are no approved therapeutic drugs for definitive treatment of this dangerous disease.

METHODS

In this article, all of the documentary information, such as clinical trials, original research and reviews, government's database, and treatment guidelines, were reviewed critically and comprehensively. Moreover, it was attempted to present the most common and effective drugs and strategies, to suggest the possible treatment way of COVID19 by focusing on the body's defense mechanism against pathogens.

RESULTS

Antiviral drugs and immune-modulatory agents with the traditional medicines using the natural compound are usual accessible treatments. Accordingly, they have better beneficence due to the large existence studies, long time follow-ups, proximity to the natural system, and the normal physiological routine of the pathogen and host interactions. Besides, the serotonergic and dopaminergic pathways are considered as attractive targets to treat human immune, infectious, and cancerous diseases. Fluoxetine, as a host-targeted small molecule with immunomodulatory action, may be known as effective drug for treatment and prevention of COVID19 disease, in combination with antiviral drugs and natural compounds.

CONCLUSION

Co-administration of fluoxetine in the treatment of COVID19 could be considered due to the possibility of its interaction with ACE2 receptors, immune-modulatory function, and a proper immune response at the right time. Fluoxetine plays a beneficial role in reducing stress due to fear of infecting by COVID19 or worsening the disease and psychological support for the affected patients.

The Applications of Carbon Nanotubes in the Diagnosis and Treatment of Lung Cancer: A Critical Review

The importance of timely diagnosis and the complete treatment of lung cancer for many people with this deadly disease daily increases due to its high mortality. Diagnosis and treatment with helping the nanoparticles are useful, although they have reasonable harms. This article points out that the side effects of using carbon nanotube (CNT) in this disease treatment process such as inflammation, fibrosis, and carcinogenesis are very problematic. Toxicity can reduce to some extent using the techniques such as functionalizing to proper dimensions as a longer length, more width, and greater curvature. The targeted CNT sensors can be connected to various modified vapors. In this regard, with helping this method, screening makes non-invasive diagnosis possible. Researchers have also found that nanoparticles such as CNTs could be used as carriers to direct drug delivery, especially with chemotherapy drugs. Most of these carriers were multi-wall carbon nanotubes (MWCNT) used for cancerous cell targeting. The results of laboratory and animal researches in the field of diagnosis and treatment became very desirable and hopeful. The collection of researches summarized has highlighted the requirement for a detailed assessment which includes CNT dose, duration, method of induction, etc., to achieve the most controlled conditions for animal and human studies. In the discussion section, 4 contradictory issues are discussed which are invited researchers to do more research to get clearer results.

An Inventive Report of Inducing Apoptosis in Non-Small Cell Lung Cancer (NSCLC) Cell Lines by Transfection of MiR-4301

BACKGROUND

Based on recent studies, new therapeutic strategies have been developed for cancer treatment using microRNAs (miRNAs). With this view, miRNAs manipulating techniques can be considered as novel therapeutic prospects for cancer treatment. In this study, we evaluated the expression of miR-4301 in human lung cancer cell lines and investigated its potential role in cell proliferation and tumor suppression on Non-Small Cell Lung Cancer (NSCLC) cells.

METHODS

We used quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) to examine the level of miR- 4301 expression in human lung cancer cell lines (A549, QU-DB) and non-malignant lung epithelial cells (HFLF-PI5). Then, we investigated the effect of miR-4301 by transfecting it into these cell lines and probing for cancer cell viability and apoptosis using the MTT assay, flow cytometry and immunofluorescence staining.

RESULTS

Our results showed that the expression level of miR-4301 was significantly reduced in human lung cancer cell lines (P<0.001). When miR-4301 was transfected in lung cancer cells, their cell proliferation was suppressed and apoptosis induced. This decline in cell survival was confirmed by the MTT assay. Transfection of miR-4301 caused an increase in early and late apoptotic cells in all lung cancer cell lines tested.

CONCLUSIONS

Our findings show that miR-4301 may act as a lung cancer suppressor through targeting of proteins involved in cell proliferation and survival. For this reason, targeting miR-4301 may provide a new strategy for the diagnosis and treatment of patients with this deadly disease. This article is protected by copyright. All rights reserved.

Using the Systems Biology Approach and Molecular Method to Investigate the Role of the Dopaminergic Pathway in Osteoarthritis: A Case Control Study

OBJECTIVE

Osteoarthritis is the most common type of arthritis and one of the leading causes of job loss and motor disabilities. Recently, the involvement of dopaminergic pathways and dopamine receptor genes has been considered in this disease. Therefore, studying and comparing the expression pattern of these receptor genes can lead to a greater understanding of the pathogenesis of this disease.

METHODS

In this research, we used the systems biology approach to investigate the role of the dopaminergic pathway in osteoarthritis. Then the gene expression pattern of dopamine receptor genes was examined in an osteoarthritis patientgroup in comparison with healthy individuals by Real-time PCR method.

RESULTS

The analysis of the transcriptome dataset of osteoarthritis identified some genes in the dopaminergic pathway and the six most important genes in this disease are in the network with a significant relationship to dopamine receptors which differentially expressed compared to health groups. Statistical analysis of the case control study showed a significant difference (P-value<0.05) in DRD1 and DRD2 family in the patients in comparison to healthy individuals.

DISCUSSION

We attained the significant expression pattern of dopamine receptors in the blood of osteoarthritis patients which could be useful to identify new strategies for the diagnosis, management, or treatment of this disease.

Association of Mental Health-Related Proteins DAXX, DRD3, and DISC1 With the Progression and Prognosis of Chondrosarcoma

Chondrosarcoma is the second most common malignant bone tumor. Current therapies remain ineffective, resulting in poor prognoses. Biomarkers for chondrosarcoma and predictors of its prognosis have not been established. Mental health-related proteins have been associated with the pathogenesis, progression, and prognosis of many cancers, but their association with chondrosarcoma has not been reported. In this study, the expression and clinicopathological significance of the mental health-related proteins DAXX, DRD3, and DISC1 in chondrosarcoma tissue samples were examined, over an 84-months follow-up period. In immunohistochemical analysis, the rates of positive DAXX, DRD3, and DISC1 expression were significantly higher in chondrosarcoma than in osteochondroma tissue (P < 0.01). The percentages of positive DAXX, DRD3, and DISC1 expression were significantly lower in tissues with good differentiation (P < 0.01), AJCC stage I/ II (P < 0.01), Enneking stage I (P < 0.01), and non-metastasis (P < 0.05), respectively. In Kaplan-Meier survival analysis, significantly shorter mean survival times were associated with moderate and poor differentiation (P = 0.000), AJCC stage III/IV (P = 0.000), Enneking stage II/III (P = 0.000), metastasis (P = 0.019), invasion (P = 0.013), and positive DAXX (P = 0.012), and/or DRD3 (P = 0.018) expression. In Cox regression analysis, moderate and poor differentiation (P = 0.006), AJCC stage III/IV (P = 0.013), Enneking stage II/III (P = 0.016), metastasis (P = 0.033), invasion (P = 0.011), and positive DAXX (P = 0.033), and/or DRD3 (P = 0.025) staining correlated negatively with the postoperative survival rate and positively with mortality. In competing-risks regression analysis, differentiation (P = 0.005), metastasis (P = 0.014), invasion (P = 0.028), AJCC stage (P = 0.003), Enneking stage (P = 0.036), and DAXX (P = 0.039), and DRD3(P = 0.019) expression were independent predictors of death from chondrosarcoma. The areas under receiver operating characteristic curves for DAXX, DRD3, and DISC1 expression were 0.673 (95% CI, 0.557-0.788; P = 0.010), 0.670 (95% CI, 0.556-0.784; P = 0.011), and 0.688 (95% CI, 0.573-0.802; P = 0.005), respectively. These results suggest that DAXX, DRD3, and DISC1 could serve as biomarkers of chondrosarcoma progression and predictors of its prognosis.

Co-Administration of Curcumin and Bromocriptine Nano-liposomes for Induction of Apoptosis in Lung Cancer Cells

Background:

In recent years, nanotechnology with modern advances in the macromolecular design of nano-carriers has proved to be helpful in the development of drugs delivery systems. This research represents a novel co-administration of nano-vehicles, known as liposomes. Liposomes efficiently encapsulate curcumin and BR in a polymer structure, which results in enhanced aqueous solubility of the mentioned hydrophobic agents and higher bioavailability of the drugs.

Methods:

Preparation of curcumin and BR liposomes were carried out by the thin film method, and the amounts of purified drug and its release were analyzed. After dose determination, the human lung cancer cells (QU-DB) were exposed to BR and curcumin liposomes for 12, 24, and 48 h. Then the viability and apoptosis assays were carried out by using MTT and flow cytometry technique, respectively.

Results:

In this research, in vitro anti-cancer effects of former nano-formulations on lung cancer cells was confirmed, and no cytotoxicity effects of these nano-preparations were observed in the normal cells (HFLF-PI5).

Conclusion:

Our findings suggest the nano-liposomal drugs as effective anti-cancer agents; however, additional clinical examinations are required.

Mechanisms of Compound Kushen Injection for the Treatment of Lung Cancer Based on Network Pharmacology

Background

Compound Kushen Injection (CKI) is a Chinese patent drug that shows good efficacy in treating lung cancer (LC). However, its underlying mechanisms need to be further clarified.

Methods

In this study, we adopted a network pharmacology method to gather compounds, predict targets, construct networks, and analyze biological functions and pathways. Moreover, molecular docking simulation was employed to assess the binding potential of selected target-compound pairs.

Results

Four networks were established, including the compound-putative target network, protein-protein interaction (PPI) network of LC targets, compound-LC target network, and herb-compound-target-pathway network. Network analysis showed that 8 targets (CHRNA3, DRD2, PRKCA, CDK1, CDK2, CHRNA5, MMP1, and MMP9) may be the therapeutic targets of CKI in LC. In addition, molecular docking simulation indicated that CHRNA3, DRD2, PRKCA, CDK1, CDK2, MMP1, and MMP9 had good binding activity with the corresponding compounds. Furthermore, enrichment analysis indicated that CKI might exert a therapeutic role in LC by regulating some important pathways, namely, pathways in cancer, proteoglycans in cancer, PI3K-Akt signaling pathway, non-small-cell lung cancer, and small cell lung cancer.

Conclusions

This study validated and predicted the mechanism of CKI in treating LC. Additionally, this study provides a good foundation for further experimental studies and promotes the reasonable application of CKI in the clinical treatment of LC.

Bromocriptine-responsive supersellar germinoma with the expression of dopamine receptors: A case report

BACKGROUND

Germinomas are sensitive to radiotherapy and chemotherapy. However, there has been no report involving in the potential therapeutic effect of dopamine agonists (DAs) such as bromocriptine on germinomas.

CASE DESCRIPTION

A 20-year-old female was presented with bitemporal visual disturbance and amenorrhea. Magnetic resonance imaging demonstrated a huge sellar tumor with upward extension and invasion of the parasellar region. The blood tests showed an exceedingly high level of prolactin. A sellar tumor with hyperprolactinemia was diagnosed, and bromocriptine was initially given. After three months, the tumor volume had been obviously decreased by 82%. However, the tumor re-grew after ten months and the endoscopic endonasal surgery was performed. Histopathological and immunohistochemical examination indicated the patient had a pure sellar germinoma. The tumor cells strongly expressed dopamine 2 receptor and dopamine 5 receptor, which located in the membrane and cytoplasm.

CONCLUSIONS

The transient but significant partial responsiveness of germinoma to bromocriptine treatment in this patient is a novel discovery, suggesting that DAs may be a potential therapeutic choice for tumors with the expression of dopamine 2/5 receptors.

DR2 blocker thioridazine: A promising drug for ovarian cancer therapy

Dopamine receptor 2 (DR2) may be a biomarker for various types of cancer. Ovarian cancer cells overexpress DR2; therefore, blocking DR2 may be a novel treatment strategy for ovarian cancer. Thioridazine, a DR2 blocker, has antineoplastic activity in a variety of cancer cells. In view of the requirement for novel therapeutic agents in ovarian cancer, the present study aimed to determine the potential effects of thioridazine in vitro and in vivo. It was revealed that the DR2 blocker thioridazine induced cell death in a dose-dependent manner in ovarian cancer cells. Thioridazine treatment induced apoptosis and autophagy, which may be attributed to an increased level of reactive oxygen species and associated DNA damage. Additionally, the expression of various proteins increased with oxidative stress, including nuclear factor E2-related factor 2, which is a pivotal transcriptional factor involved in cellular responses to oxidative stress. Heme oxygenase 1, NAPDH quinone dehydrogenase 1 and hypoxia inducible factor-1α and phosphorylated (p)-protein kinase B expression was significantly decreased, and the expression level of p-extracellular signal-related kinases and p-P38 was increased. Using 3-methyl adenine to inhibit autophagy caused the rate of apoptosis to increase. Thioridazine inhibited the growth of SKOV3 xenografts in nude mice. The present study demonstrated that the DR2 blocker thioridazine exhibited anticancer effects in vitro and in vivo, suggesting that thioridazine may be used as a potential drug in ovarian cancer therapy.

Activation of DRD5 (dopamine receptor D5) inhibits tumor growth by autophagic cell death

Dopamine agonists such as bromocriptine and cabergoline have been successfully used in the treatment of pituitary prolactinomas and other neuroendocrine tumors. However, their therapeutic mechanisms are not fully understood. In this study we demonstrated that DRD5 (dopamine receptor D5) agonists were potent inhibitors of pituitary tumor growth. We further found that DRD5 activation increased production of reactive oxygen species (ROS), inhibited the MTOR pathway, induced macroautophagy/autophagy, and led to autophagic cell death (ACD) in vitro and in vivo. In addition, DRD5 protein was highly expressed in the majority of human pituitary adenomas, and treatment of different human pituitary tumor cell cultures with the DRD5 agonist SKF83959 resulted in growth suppression, and the efficacy was correlated with the expression levels of DRD5 in the tumors. Furthermore, we found that DRD5 was expressed in other human cancer cells such as glioblastomas, colon cancer, and gastric cancer. DRD5 activation in these cell lines suppressed their growth, inhibited MTOR activity, and induced autophagy. Finally, in vivo SKF83959 also inhibited human gastric cancer cell growth in nude mice. Our studies revealed novel mechanisms for the tumor suppressive effects of DRD5 agonists, and suggested a potential use of DRD5 agonists as a novel therapeutic approach in the treatment of different human tumors and cancers.

Activation of D2 Dopamine Receptors in CD133+ve Cancer Stem Cells in Non-small Cell Lung Carcinoma Inhibits Proliferation, Clonogenic Ability, and Invasiveness of These Cells

Lung carcinoma is the leading cause of cancer-related death worldwide, and among this cancer, non-small cell lung carcinoma (NSCLC) comprises the majority of cases. Furthermore, recurrence and metastasis of NSCLC correlate well with CD133+ve tumor cells, a small population of tumor cells that have been designated as cancer stem cells (CSC). We have demonstrated for the first time high expression of D₂ dopamine (DA) receptors in CD133+ve adenocarcinoma NSCLC cells. Also, activation of D₂ DA receptors in these cells significantly inhibited their proliferation, clonogenic ability, and invasiveness by suppressing extracellular signal-regulated kinases 1/2 (ERK1/2) and AKT, as well as down-regulation of octamer-binding transcription factor 4 (Oct-4) expression and matrix metalloproteinase-9 (MMP-9) secretion by these cells. These results are of significance as D₂ DA agonists that are already in clinical use for treatment of other diseases may be useful in combination with conventional chemotherapy and radiotherapy for better management of NSCLC patients by targeting both tumor cells and stem cell compartments in the tumor mass.

Genetic and Functional Analysis of Polymorphisms in the Human Dopamine Receptor and Transporter Genes in Small Cell Lung Cancer

The regulatory role of dopamine (DA) in endocrine, cardiovascular and renal functions has been extensively studied and used for clinical purposes. More recently DA has been indicated as a regulatory molecule for immune cells and malignant cell proliferation. We assessed the expression and the functional role DA, DA receptors, and transporters in primary small cell lung cancer (SCLC). By HPLC DA plasma levels were more elevated in SCLC patients in comparison with NSCLC patients and healthy controls. SCLC cell expressed DA D1- and D2-like receptors and membrane and vesicular transporters at protein and mRNA levels. We also investigated the effects of independent D1- or D2-like receptor stimulation on SCLC cell cultures. DA D1 receptor agonist SKF38393 induced the increase of cAMP levels and DARPP-32 protein expression without affecting SCLC growth rate. Cell treatment with the DA D1 receptor antagonist SCH23390 inhibited SKF38393 effects. In contrast, the DA D2 receptor agonist quinpirole (10 μM) counteracted, in a dose and time dependent way, SCLC cell proliferation, it did not affect cAMP levels and decreased phosphorylated AKT that was induced by DA D2 receptor antagonist sulpiride. However, in only one SCLC line, stimulation of DA D2 receptor failed to inhibit cell proliferation in vitro. This effect was associated to the existence of rs6275 and rs6277 polymorphisms in the D2 gene. These results gave more insight into DA control of lung cancer cell behavior and suggested the existence of different SCLC phenotypes.

Thioridazine, an antipsychotic drug, elicits potent antitumor effects in gastric cancer

Thioridazine, an antipsychotic drug, has been reported to induce apoptosis in various types of cancer cells, with specificity on targeting cancer stem cells (CSCs). However, whether it elicits anticancer effects in gastric cancer has never been reported. In the present study, we examined the ability of thioridazine to induce cell death in the gastric cancer cell lines NCI-N87 and AGS, and detected its in vivo tumor inhibition capacity. Thioridazine elicited cytotoxic effects on NCI-N87 and AGS cells in a dose-dependent manner, and inhibited the colony formation abilitiy of the NCI-N87 and AGS cells. Thioridazine treatment induced nuclear fragmentation, increased the proportion of sub-G1 phase cells, and elevated the percentage of Annexin V-positive cells, suggesting the occurrence of apoptosis. Moreover, thioridazine induced gastric cancer cell apoptosis in a caspase-dependent manner, as shown by a decrease in the precursors of casapse-9, caspase-8 and caspase-3, and by the ability of the caspase inhibitor Z-VAD-FMK to reverse the cytotoxic effect of thioridazine. JC-1 staining further revealed that thioridazine induced gastric cancer cell apoptosis via the mitochondrial pathway. In addition, thioridazine pretreatment inhibited the growth of NCI-N87 cell-derived tumors. The present study demonstrated that the antipsychotic drug thioridazine possesses anti-gastric cancer ability through in vitro and in vivo experiments, suggesting thioridazine as a potential drug in gastric cancer therapy.