Nelfinavir, an HIV protease inhibitor, induces apoptosis and cell cycle arrest in human cervical cancer cells via the ROS-dependent mitochondrial pathway

PPP2R1A silencing suppresses LUAD progression by sensitizing cells to nelfinavir-induced apoptosis and pyroptosis

Lung adenocarcinoma is a major public health problem with the low 5-year survival rate (15%) among cancers. Aberrant alterations of meiotic genes, which have gained increased attention recently, might contribute to elevated tumor risks. However, systematic and comprehensive studies based on the relationship between meiotic genes and LUAD recurrence and treatment response are still lacking. In this manuscript, we first confirmed that the meiosis related prognostic model (MRPM) was strongly related to LUAD progression via LASSO-Cox regression analyses. Furthermore, we identified the role of PPP2R1A in LUAD, which showed more contributions to LUAD process compared with other meiotic genes in our prognostic model. Additionally, repression of PPP2R1A enhances cellular susceptibility to nelfinavir-induced apoptosis and pyroptosis. Collectively, our findings indicated that meiosis-related genes might be therapeutic targets in LUAD and provided crucial guidelines for LUAD clinical intervention.

Repurposing approved non-oncology drugs for cancer therapy: a comprehensive review of mechanisms, efficacy, and clinical prospects

Cancer poses a significant global health challenge, with predictions of increasing prevalence in the coming years due to limited prevention, late diagnosis, and inadequate success with current therapies. In addition, the high cost of new anti-cancer drugs creates barriers in meeting the medical needs of cancer patients, especially in developing countries. The lengthy and costly process of developing novel drugs further hinders drug discovery and clinical implementation. Therefore, there has been a growing interest in repurposing approved drugs for other diseases to address the urgent need for effective cancer treatments. The aim of this comprehensive review is to provide an overview of the potential of approved non-oncology drugs as therapeutic options for cancer treatment. These drugs come from various chemotherapeutic classes, including antimalarials, antibiotics, antivirals, anti-inflammatory drugs, and antifungals, and have demonstrated significant antiproliferative, pro-apoptotic, immunomodulatory, and antimetastatic properties. A systematic review of the literature was conducted to identify relevant studies on the repurposing of approved non-oncology drugs for cancer therapy. Various electronic databases, such as PubMed, Scopus, and Google Scholar, were searched using appropriate keywords. Studies focusing on the therapeutic potential, mechanisms of action, efficacy, and clinical prospects of repurposed drugs in cancer treatment were included in the analysis. The review highlights the promising outcomes of repurposing approved non-oncology drugs for cancer therapy. Drugs belonging to different therapeutic classes have demonstrated notable antitumor effects, including inhibiting cell proliferation, promoting apoptosis, modulating the immune response, and suppressing metastasis. These findings suggest the potential of these repurposed drugs as effective therapeutic approaches in cancer treatment. Repurposing approved non-oncology drugs provides a promising strategy for addressing the urgent need for effective and accessible cancer treatments. The diverse classes of repurposed drugs, with their demonstrated antiproliferative, pro-apoptotic, immunomodulatory, and antimetastatic properties, offer new avenues for cancer therapy. Further research and clinical trials are warranted to explore the full potential of these repurposed drugs and optimize their use in treating various cancer types. Repurposing approved drugs can significantly expedite the process of identifying effective treatments and improve patient outcomes in a cost-effective manner.

Therapeutic Potential of Targeting the Cytochrome P450 Enzymes Using Lopinavir/Ritonavir in Colorectal Cancer: A Study in Monolayers, Spheroids and In Vivo Models

Cytochrome P450 (CYP450) enzyme has been shown to be expressed in colorectal cancer (CRC) and its dysregulation is linked to tumor progression and a poor prognosis. Here we investigated the therapeutic potential of targeting CYP450 using lopinavir/ritonavir in CRC. The integrative systems biology method and RNAseq were utilized to investigate the differential levels of genes associated with patients with colorectal cancer. The antiproliferative activity of lopinavir/ritonavir was evaluated in both monolayer and 3-dimensional (3D) models, followed by wound-healing assays. The effectiveness of targeting CYP450 was examined in a mouse model, followed by histopathological analysis, biochemical tests (MDA, SOD, thiol, and CAT), and RT-PCR. The data of dysregulation expressed genes (DEG) revealed 1268 upregulated and 1074 down-regulated genes in CRC. Among the top-score genes and dysregulated pathways, CYPs were detected and associated with poor prognosis of patients with CRC. Inhibition of CYP450 reduced cell proliferation via modulating survivin, Chop, CYP13a, and induction of cell death, as detected by AnnexinV/PI staining. This agent suppressed the migratory behaviors of cells by induction of E-cadherin. Moreover, lopinavir/ritonavir suppressed tumor growth and fibrosis, which correlated with a reduction in SOD/thiol levels and increased MDA levels. Our findings illustrated the therapeutic potential of targeting the CYP450 using lopinavir/ritonavir in colorectal cancer, supporting future investigations on this novel therapeutic approach for the treatment of CRC.

ZYY-B-2, a novel ALK inhibitor, overcomes resistance to ceritinib by inhibiting P-gp function and induces apoptosis through mitochondrial pathway in ceritinib-resistant H2228 cells

Targeting the Echinoderm microtubule-associated protein-like 4 and anaplastic lymphoma kinase (EML4-ALK) fusion gene is a promising therapeutic strategy for non-small-cell lung cancer (NSCLC) patients. With the advent of the first- and second-generation ALK inhibitors, the mortality rate of lung cancer has shown a downward trend, but almost inevitably, patients will eventually develop resistance, which severely limits the clinical application. Hence, developing new ALK inhibitors which can overcome resistance is essential. Here, we synthesized a novel ALK inhibitor 1-[4-[[5-Chloro-4-[[2-[(1-methylethyl)sulfonyl]phenyl]amino]-2-pyrimidinyl]amino]-3-methoxyphenyl]-3-[2-(4-methyl-1-piperazinyl)-2-oxoethyl]-2-imidazolidinone (ZYY-B-2) based on the structure of the second-generation ALK inhibitor ceritinib. ZYY-B-2 exhibited impressive anti-proliferative effect in the EML4-ALK positive H2228 cells and ceritinib-resistant H2228 (H2228/Cer) cells. Meanwhile, ZYY-B-2 inhibited the activation of p-ALK in a concentration-dependent manner, and inactivated its downstream target proteins p-AKT and p-ERK to inhibit cell proliferation. Subsequently, we found that ZYY-B-2 blocked H2228 cells and H2228/Cer cells in G0/G1 phase and induced cells to undergo apoptosis through the mitochondrial pathway. The ability of its anti-proliferation and pro-apoptosis was significantly stronger than the second generation ALK inhibitor ceritinib. In addition, high expression of P-gp was found in H2228/Cer cells compared with H2228 cells. ZYY-B-2 could inhibit the expression of P-gp in a dose-dependent manner to overcome ceritinib resistance, and the suppression effect of ZYY-B-2 on P-gp might be related to its inhibition of PI3K/AKT signaling pathway. In summary, ZYY-B-2, a promising ALK inhibitor, shows potent activity against ceritinib-resistant cells, which provides experimental and theoretical basis for the further development of new ALK inhibitors.

Deficiency of kin17 Facilitates Apoptosis of Cervical Cancer Cells by Modulating Caspase 3, PARP, and Bcl-2 Family Proteins

Background

The treatment of cervical cancer in the late stage is still quite challenging, because of nonspecificity in conventional therapies and the lack of molecular targeted drugs. It is necessary to find novel biomarkers for cervical cancer treatment.

Methods

In the present study, cervical cell lines HeLa and SiHa with kin17 knockdown were constructed by transfection of the recombinant lentiviral vector carrying KIN17 siRNA and screened by puromycin. The established cells with kin17 knockdown were determined by fluorescence observation and western blotting. Cell apoptosis and the mitochondrial membrane potential (MMP) were detected by flow cytometry. The activity of caspase 3 enzyme was tested by spectrophotometry. The expression profile of apoptosis-associated proteins was analyzed by western blotting. Finally, we used bioinformatics and proteomic data to analyze KIN-related genes in cervical cancer.

Results

The results showed high fluorescent positive rates (>90%) and high gene silencing efficiency (>65%) in HeLa and SiHa cells transfected with gene silencing vectors. Moreover, kin17 deficiency decreased the MMP and increased the apoptosis rates in HeLa and SiHa cells, respectively. Furthermore, knockdown of kin17 enhanced the activity of caspase 3 enzyme, increased the expression of cleaved PARP and Bim, while decreasing the expression of Bcl-xL and phosphorylated BAD in HeLa and SiHa cells. Identification of KIN-related prognostic genes in cervical cancer revealed that a total of 5 genes (FZR1, IMPDH1, GPKOW, XPA, and DDX39A) were constructed for this risk score, and the results showed that CTLA4 expressions were negatively correlated with the risk score.

Conclusion

Our findings demonstrated that kin17 knockdown facilitates apoptosis of cervical cancer cells by targeting caspase 3, PARP, and Bcl-2 family proteins. Besides, kin17 could regulate cancer cell apoptosis through the mitochondrial pathway and could be used as a novel therapeutic target for the regulation of cell apoptosis in cervical cancer.

Polymerase ζ is Involved in Mitochondrial DNA Maintenance Processes in Concert with APE1 Activity

Mitochondrial DNA (mtDNA) damaged by reactive oxygen species (ROS) triggers so far poorly understood processes of mtDNA maintenance that are coordinated by a complex interplay among DNA repair, DNA degradation, and DNA replication. This study was designed to identify the proteins involved in mtDNA maintenance by applying a special long-range PCR, reflecting mtDNA integrity in the minor arc. A siRNA screening of literature-based candidates was performed under conditions of enforced oxidative phosphorylation revealing the functional group of polymerases and therein polymerase ζ (POLZ) as top hits. Thus, POLZ knockdown caused mtDNA accumulation, which required the activity of the base excision repair (BER) nuclease APE1, and was followed by compensatory mtDNA replication determined by the single-cell mitochondrial in situ hybridization protocol (mTRIP). Quenching reactive oxygen species (ROS) in mitochondria unveiled an additional, ROS-independent involvement of POLZ in the formation of a typical deletion in the minor arc region. Together with data demonstrating the localization of POLZ in mitochondria, we suggest that POLZ plays a significant role in mtDNA turnover, particularly under conditions of oxidative stress.

Molecular Mechanisms of HIV Protease Inhibitors Against HPV-Associated Cervical Cancer: Restoration of TP53 Tumour Suppressor Activities

Cervical cancer is a Human Papilloma virus-related disease, which is on the rise in a number of countries, globally. Two essential oncogenes, E6 and E7, drive cell transformation and cancer development. These two oncoproteins target two of the most important tumour suppressors, p53 and pRB, for degradation through the ubiquitin ligase pathway, thus, blocking apoptosis activation and deregulation of cell cycle. This pathway can be exploited for anticancer therapeutic interventions, and Human Immunodeficiency Virus Protease Inhibitors (HIV-PIs) have attracted a lot of attention for this anticancer drug development. HIV-PIs have proven effective in treating HPV-positive cervical cancers and shown to restore impaired or deregulated p53 in HPV-associated cervical cancers by inhibiting the 26S proteasome. This review will evaluate the role players, such as HPV oncoproteins involved cervical cancer development and how they are targeted in HIV protease inhibitors-induced p53 restoration in cervical cancer. This review also covers the therapeutic potential of HIV protease inhibitors and molecular mechanisms behind the HIV protease inhibitors-induced p53-dependent anticancer activities against cervical cancer.

Longitudinal Follow-Up of Blood Telomere Length in HIV-Exposed Uninfected Children Having Received One Year of Lopinavir/Ritonavir or Lamivudine as Prophylaxis

Telomere shortening can be enhanced upon human immunodeficiency virus (HIV) infection and by antiretroviral (ARV) exposures. The aim of this study was to evaluate the acute and long-term effect on telomere shortening of two ARV prophylaxes, lopinavir/ritonavir (LPV/r) and lamivudine (3TC), administered to children who are HIV-exposed uninfected (CHEU) to prevent HIV acquisition through breastfeeding during the first year of life, and to investigate the relationship between telomere shortening and health outcomes at six years of age. We included 198 CHEU and measured telomere length at seven days of life, at week-50 and at six years (year-6) using quantitative polymerase chain reaction. At week-50, telomere shortening was observed among 44.3% of CHEU, irrespective of the prophylactic treatment. Furthermore, this telomere shortening was neither associated with poor growth indicators nor neuropsychological outcomes at year-6, except for motor abilities (MABC test n = 127, β = -3.61, 95%CI: -7.08, -0.14; p = 0.04). Safety data on telomere shortening for infant HIV prophylaxis are scarce. Its association with reduced motor abilities deserves further attention among CHEU but also HIV-infected children receiving ARV treatment.

Repurposing of Antimicrobial Agents for Cancer Therapy: What Do We Know?

The substantial costs of clinical trials, the lengthy timelines of new drug discovery and development, along the high attrition rates underscore the need for alternative strategies for finding quickly suitable therapeutics agents. Given that most approved drugs possess more than one target tightly linked to other diseases, it encourages promptly testing these drugs in patients. Over the past decades, this has led to considerable attention for drug repurposing, which relies on identifying new uses for approved or investigational drugs outside the scope of the original medical indication. The known safety of approved drugs minimizes the possibility of failure for adverse toxicology, making them attractive de-risked compounds for new applications with potentially lower overall development costs and shorter development timelines. This latter case is an exciting opportunity, specifically in oncology, due to increased resistance towards the current therapies. Indeed, a large body of evidence shows that a wealth of non-cancer drugs has beneficial effects against cancer. Interestingly, 335 drugs are currently being evaluated in different clinical trials for their potential activities against various cancers (Redo database). This review aims to provide an extensive discussion about the anti-cancer activities exerted by antimicrobial agents and presents information about their mechanism(s) of action and stage of development/evaluation.

Molecular and Cellular Mechanisms of Metformin in Cervical Cancer

Simple Summary

The potential effects of metformin in terms of cancer prevention and therapy have been widely studied, and a number of studies have indicated its potential role in cancer treatment. Metformin exerts anticancer effects, alone or in combination with other agents, on cervical cancer in vitro and in vivo. Metformin might thus serve as an adjunct therapeutic agent for cervical cancer.

Abstract

Cervical cancer is one of the major gynecologic malignancies worldwide. Treatment options include chemotherapy, surgical resection, radiotherapy, or a combination of these treatments; however, relapse and recurrence may occur, and the outcome may not be favorable. Metformin is an established, safe, well-tolerated drug used in the treatment of type 2 diabetes; it can be safely combined with other antidiabetic agents. Diabetes, possibly associated with an increased site-specific cancer risk, may relate to the progression or initiation of specific types of cancer. The potential effects of metformin in terms of cancer prevention and therapy have been widely studied, and a number of studies have indicated its potential role in cancer treatment. The most frequently proposed mechanism underlying the diabetes–cancer association is insulin resistance, which leads to secondary hyperinsulinemia; furthermore, insulin may exert mitogenic effects through the insulin-like growth factor 1 (IGF-1) receptor, and hyperglycemia may worsen carcinogenesis through the induction of oxidative stress. Evidence has suggested clinical benefits of metformin in the treatment of gynecologic cancers. Combining current anticancer drugs with metformin may increase their efficacy and diminish adverse drug reactions. Accumulating evidence is indicating that metformin exerts anticancer effects alone or in combination with other agents in cervical cancer in vitro and in vivo. Metformin might thus serve as an adjunct therapeutic agent for cervical cancer. Here, we reviewed the potential anticancer effects of metformin against cervical cancer and discussed possible underlying mechanisms.

Studies on apoptosis induced by B-norcholesteryl benzimidazole compounds in HeLa cells

Certain B-norcholesteryl benzimidazole compounds were found to mediate marked anti-tumor proliferative effects in vitro in our earlier study. Here, the mechanism of action of these anti-tumor effects was evaluated using HeLa human cervical cancer cells. Methods for detecting cell invasion and migration, Annexin V-PI double staining, cell cycle status, and mitochondrial membrane potential Δψ_m were employed. These compounds were confirmed to significantly inhibit the proliferation of HeLa cells in vitro. Compound 1 induced apoptosis in S phase, compound 2induced apoptosis in the G₀/G₁ phase and compound 3 induced late apoptosis in the G₂/M phase. These compounds induced HeLa cell apoptosis through depolarization of mitochondrial membrane potential Δψ_m in a dose-dependent manner. B-norcholesteryl benzimidazole compounds induced morphological changes in HeLa cells and inhibited proliferation, invasion and metastasis. Apoptosis was promoted by mechanisms involving p21 and p53 in this cervical cancer cell line.

The double-edged roles of ROS in cancer prevention and therapy

Reactive oxygen species (ROS) serve as cell signaling molecules generated in oxidative metabolism and are associated with a number of human diseases. The reprogramming of redox metabolism induces abnormal accumulation of ROS in cancer cells. It has been widely accepted that ROS play opposite roles in tumor growth, metastasis and apoptosis according to their different distributions, concentrations and durations in specific subcellular structures. These double-edged roles in cancer progression include the ROS-dependent malignant transformation and the oxidative stress-induced cell death. In this review, we summarize the notable literatures on ROS generation and scavenging, and discuss the related signal transduction networks and corresponding anticancer therapies. There is no doubt that an improved understanding of the sophisticated mechanism of redox biology is imperative to conquer cancer.

Oxidative stress and endoplasmic reticulum stress contribute to L. paracasei subsp. paracasei M5L exopolysaccharide-induced apoptosis in HT-29 cells

Colorectal cancer is the third most malignant cancer occurring around the world. Effective prevention and treatment have been increasingly the focus of global attention. Long-term diet of fermented dairy inhibits proliferation of colon cancer cell, which is considered that not only live lactic acid bacteria but also the secreted exopolysaccharides exert the function. In this scenario, this study aimed to investigate the mechanism of growth inhibition on HT-29 cells induced in vitro by exopolysaccharides isolated from Lactobacillus paracasei subsp. paracasei M5L (M5-EPSs). HT-29 cells which were treated by a set of concentrations of M5-EPSs have been investigated of cell viability, characteristic changes, cell cycle distribution, and redox system. The results demonstrated that M5-EPSs treatments induced HT-29 cell apoptosis and resulted in upregulation of ROS levels and downregulation of antioxidant enzyme activities, leading to an imbalance in the oxidation system in HT-29 cells. In response to M5-EPSs, endogenous ER stress (ERS) markers, including GRP78, ATF4, and CHOP, were transcriptionally altered so that activating the ERS in HT-29 cells. After NAC treatment, the oxidative stress was inhibited, and the expression of GRP78 and CHOP was significantly decreased, indicating that oxidative stress can significantly affect the ERS pathway. Furthermore, it suggested that the occurrence of apoptosis was associated with Bcl-2 gene family. In conclusion, this study demonstrated that M5-EPSs can induce HT-29 cells apoptosis by destroying the redox system through activation of the ERS signaling pathway.

HIV-1 Protease Inhibitors Slow HPV16-Driven Cell Proliferation through Targeted Depletion of Viral E6 and E7 Oncoproteins

High-risk human papillomavirus strain 16 (HPV16) causes oral and anogenital cancers through the activities of two viral oncoproteins, E6 and E7, that dysregulate the host p53 and pRb tumor suppressor pathways, respectively. The maintenance of HPV16-positive cancers requires constitutive expression of E6 and E7. Therefore, inactivating these proteins could provide the basis for an anticancer therapy. Herein we demonstrate that a subset of aspartyl protease inhibitor drugs currently used to treat HIV/AIDS cause marked reductions in HPV16 E6 and E7 protein levels using two independent cell culture models: HPV16-transformed CaSki cervical cancer cells and NIKS16 organotypic raft cultures (a 3-D HPV16-positive model of epithelial pre-cancer). Treatment of CaSki cells with some (lopinavir, ritonavir, nelfinavir, and saquinavir) but not other (indinavir and atazanavir) protease inhibitors reduced E6 and E7 protein levels, correlating with increased p53 protein levels and decreased cell viability. Long-term (>7 day) treatment of HPV16-positive NIKS16 raft cultures with saquinavir caused epithelial atrophy with no discernible effects on HPV-negative rafts, demonstrating selectivity. Saquinavir also reduced HPV16's effects on markers of the cellular autophagy pathway in NIKS16 rafts, a hallmark of HPV-driven pre-cancers. Taken together, these data suggest HIV-1 protease inhibitors be studied further in the context of treating or preventing HPV16-positive cancers.

Organosulphur Compounds Induce Apoptosis and Cell Cycle Arrest in Cervical Cancer Cells via Downregulation of HPV E6 and E7 Oncogenes

BACKGROUND

The quest for strong, safe and cost-effective natural antiproliferative agents that could reduce cancer has been the focus now a days. In this regard, the organosulfur compounds from garlic (Allium sativum L.), like Diallyl Sulfide (DAS) and Diallyl Disulfide (DADS), have been shown to exhibit potent antiproliferative and anticancer properties in many studies. However, the potential of these compounds against viral oncoproteins in cervical cancer has not been fully elucidated yet.

OBJECTIVE

The objective of this study was to analyze the antiproliferative and apoptotic properties of DADS and DAS in HPV16+ human cervical cancer Caski cell line.

METHODS

Caski (cervical cancer cells) were cultured and followed by the treatment of various concentrations of organosulphur compounds (DADS and DAS), cell viability was measured by MTT assay. The apoptotic assay was performed by DAPI and Hoechst3342 staining. Reactive Oxygen Species (ROS) was estimated by DCFDA staining protocol. The distributions of cell cycle and apoptosis (FITC-Annexin V assay) were analyzed by flow cytometry. Finally, gene expression analysis was performed via quantitative real time PCR.

RESULTS

Our results showed that DAS and DADS exerted a significant antiproliferative effect on Caski cells by reducing the cell viability and inducing a dose-related increment in intracellular ROS production along with apoptosis in Caski cells. DAS and DADS also induced cell cycle arrest in G0/G1 phase, which was supported by the downregulation of cyclin D1 and CDK4 and upregulation of CDK inhibitors p21WAF1/CIP1 and p27KIP1 in Caski cells. Additionally, DAS and DADS lead to the downregulation of viral oncogene E6 and E7 and restoration of p53 function.

CONCLUSION

Thus, this study confirms the efficacy of both the organosulfur compounds DADS and DAS against cervical cancer cells.

The Anti-Cancer Properties of the HIV Protease Inhibitor Nelfinavir

Simple Summary

To this day, cancer remains a medical challenge despite the development of cutting-edge diagnostic methods and therapeutics. Thus, there is a continual demand for improved therapeutic options for managing cancer patients. However, novel drug development requires decade-long time commitment and financial investments. Repurposing approved and market-available drugs for cancer therapy is a way to reduce cost and the timeframe for developing new therapies. Nelfinavir is an anti-infective agent that has extensively been used to treat acquired immunodeficiency syndrome (AIDS) in adult and pediatric patients. In addition to its anti-infective properties, nelfinavir has demonstrated potent off-target anti-cancer effects, suggesting that it could be a suitable candidate for drug repurposing for cancer. In this review, we systematically compiled the therapeutic benefits of nelfinavir against cancer as a single drug or in combination with chemoradiotherapy, and outlined the possible underlying mechanistic pathways contributing to the anti-cancer effects.

Abstract

Traditional cancer treatments may lose efficacy following the emergence of novel mutations or the development of chemoradiotherapy resistance. Late diagnosis, high-cost of treatment, and the requirement of highly efficient infrastructure to dispense cancer therapies hinder the availability of adequate treatment in low-income and resource-limited settings. Repositioning approved drugs as cancer therapeutics may reduce the cost and timeline for novel drug development and expedite the availability of newer, efficacious options for patients in need. Nelfinavir is a human immunodeficiency virus (HIV) protease inhibitor that has been approved and is extensively used as an anti-infective agent to treat acquired immunodeficiency syndrome (AIDS). Yet nelfinavir has also shown anti-cancer effects in in vitro and in vivo studies. The anti-cancer mechanism of nelfinavir includes modulation of different cellular conditions, such as unfolded protein response, cell cycle, apoptosis, autophagy, the proteasome pathway, oxidative stress, the tumor microenvironment, and multidrug efflux pumps. Multiple clinical trials indicated tolerable and reversible toxicities during nelfinavir treatment in cancer patients, either as a monotherapy or in combination with chemo- or radiotherapy. Since orally available nelfinavir has been a safe drug of choice for both adult and pediatric HIV-infected patients for over two decades, exploiting its anti-cancer off-target effects will enable fast-tracking this newer option into the existing repertoire of cancer chemotherapeutics.

Knockdown of TRAP1 promotes cisplatin-induced apoptosis by promoting the ROS-dependent mitochondrial dysfunction in lung cancer cells

The tumor necrosis factor receptor-associated protein 1 (TRAP1) is associated with the occurrence and development of various diseases, including inflammation and cancer. However, the role and mechanism of TRAP1 in the development of lung cancer need to be further explored. Therefore, the purpose of this study is to investigate the role of TRAP1 in the regulation of apoptosis by cisplatin and its special mechanism. The RT-qPCR and Western blot were used to detect the mRNA and protein expression of ANGPTL4 in A549 and H1299 cells, respectively. And the cell apoptosis and cell cycle were measured by flow cytometry (FCM). The expression of genes related to apoptosis and drug resistance as well as the cell cycle regulators, including MDM2, CyclinB1, and CDK1, were detected by Western blot. Finally, the reactive oxygen species (ROS) indicator DCFH-DA was performed to detect the generation of ROS, and the mitochondrial membrane potential (ΔΨm) was detected by JC-1 staining. The results showed that the expression of TRAP1 was significantly increased in A549/DDP and H1299/DDP than A549 and H1299 cells. Further research found that knockdown of TRAP1 induced apoptosis and caused G2/M cell cycle arrest in A549/DDP and H1299/DDP cells. What is more, siTRAP1 reduced the relative JC-1 polymer monomer fluorescence ratio and decreased the ΔΨm, up-regulated the expression of Cytochrome C. Importantly, siTRAP1 induces ROS-dependent mitochondrial dysfunction. It is suggested that that TRAP1 suppresses cisplatin-induced apoptosis by promoting ROS-dependent mitochondrial dysfunction.

Efavirenz induces DNA damage response pathway in lung cancer

The cell-cycle related genes are potential gene targets in understanding the effects of efavirenz (EFV) in lung cancer. The present study aimed at investigating the expression changes of cell-cycle related genes in response to EFV drug treatment in human non-small cell lung carcinoma (A549) and normal lung fibroblast (MRC-5) cells. The loss in nuclear integrity in response to EFV was detected by 4', 6-diamidino-2-phenylindole (DAPI) staining. Gene expression profiling was performed using human cell cycle PathwayFinder RT² Profiler™ PCR Array. The expression changes of 84 genes key to the cell cycle pathway in humans following EFV treatment was examined. The R² PCR Array analysis revealed a change in expression of selected gene targets (including MAD2L2, CASP3, AURKB). This change in gene expression was at least a two-fold between test (EFV treated) and the control. RT-qPCR confirmed the PCR array data. In addition to this, the ATM signaling pathway was shown to be upregulated following EFV treatment in MRC-5 cells. In particular, ATM's upstream activation resulted in p53 upregulation in normal lung fibroblasts. Interestingly, the p53 signaling pathway was activated irrespective of the repressed ATM pathway in A549 cells as revealed by the Ingenuity Pathway Analysis (IPA). These EFV effects are similar to those of ionizing radiation and this suggests that EFV has anti-tumour properties.

Mitochondrial DNA Parameters in Blood of Infants Receiving Lopinavir/Ritonavir or Lamivudine Prophylaxis to Prevent Breastfeeding Transmission of HIV-1

Children who are human immunodeficiency virus (HIV)-exposed but uninfected (CHEU) accumulate maternal HIV and antiretroviral exposures through pregnancy, postnatal prophylaxis, and breastfeeding. Here, we compared the dynamics of mitochondrial DNA (mtDNA) parameters in African breastfed CHEU receiving lopinavir/ritonavir (LPV/r) or lamivudine (3TC) pre-exposure prophylaxis during the first year of life. The number of mtDNA copies per cell (MCN) and the proportion of deleted mtDNA (MDD) were assessed at day 7 and at week 50 post-delivery (PrEP group). mtDNA depletion was defined as a 50% or more decrease from the initial value, and mtDNA deletions was the detection of mtDNA molecules with large DNA fragment loss. We also performed a sub-analysis with CHEU who did not receive a prophylactic treatment in South Africa (control group). From day seven to week 50, MCN decreased with a median of 41.7% (interquartile range, IQR: 12.1; 64.4) in the PrEP group. The proportion of children with mtDNA depletion was not significantly different between the two prophylactic regimens. Poisson regressions showed that LPV/r and 3TC were associated with mtDNA depletion (reference: control group; LPV/r: PR = 1.75 (CI95%: 1.15–2.68), p < 0.01; 3TC: PR = 1.54 (CI95%: 1.00–2.37), p = 0.05). Moreover, the proportion of children with MDD was unexpectedly high before randomisation in both groups. Long-term health impacts of these mitochondrial DNA parameters should be investigated further for both CHEU and HIV-infected children receiving LPV/r- or 3TC- based regimens.

Emodin Alleviates Hydrogen Peroxide-Induced Inflammation and Oxidative Stress via Mitochondrial Dysfunction by Inhibiting the PI3K/mTOR/GSK3β Pathway in Neuroblastoma SH-SY5Y Cells

Emodin is an active monomer extracted from rhubarb root, which has many biological functions, including anti-inflammation, antioxidation, anticancer, and neuroprotection. However, the protective effect of emodin on nerve injury needs to be further elucidated. The purpose of this study is to investigate the effect of emodin on the neuroprotection and the special molecular mechanism. Here, the protective activity of emodin inhibiting H2O2-induced apoptosis and neuroinflammation as well as its molecular mechanisms was examined using human neuroblastoma cells (SH-SY5Y cells). The results showed that emodin significantly enhanced cell viability, reduced cell apoptosis and LDH release. Simultaneously, emodin downregulated H2O2-induced inflammatory factors, including IL-6, NO, and TNF-α, and alleviated H2O2-induced oxidative stress and mitochondrial dysfunction in SH-SY5Y cells. In addition, emodin inhibited the activation of the PI3K/mTOR/GSK3β signaling pathway. What is more, the PI3K/mTOR/GSK3β pathway participated in the protective mechanism of emodin on H2O2-induced cell damage. Collectively, it suggests that emodin alleviates H2O2-induced apoptosis and neuroinflammation potentially by regulating the PI3K/mTOR/GSK3β signaling pathway.

Piperlongumine Induces Cell Cycle Arrest via Reactive Oxygen Species Accumulation and IKKβ Suppression in Human Breast Cancer Cells

Piperlongumine (PL), a natural product derived from long pepper (Piper longum L.), is known to exhibit anticancer effects. However, the effect of PL on cell cycle-regulatory proteins in estrogen receptor (ER)-positive breast cancer cells is unclear. Therefore, we investigated whether PL can modulate the growth of ER-positive breast cancer cell line, MCF-7. We found that PL decreased MCF-7 cell proliferation and migration. Flow cytometric analysis demonstrated that PL induced G2/M phase cell cycle arrest. Moreover, PL significantly modulated the mRNA levels of cyclins B1 and D1, cyclin-dependent kinases 1, 4, and 6, and proliferating cell nuclear antigen. PL induced intracellular reactive oxygen species (hydrogen peroxide) accumulation and glutathione depletion. PL-mediated inhibition of IKKβ expression decreased nuclear translocation of NF-κB p65. Furthermore, PL significantly increased p21 mRNA levels. In conclusion, our data suggest that PL exerts anticancer effects in ER-positive breast cancer cells by inhibiting cell proliferation and migration via ROS accumulation and IKKβ suppression.

Sanguinarine exhibits potent efficacy against cervical cancer cells through inhibiting the STAT3 pathway in vitro and in vivo

Background

Cervical cancer is the third most common malignancy among female cancer patients worldwide. Signal transducer and activator of transcription 3 (STAT3) is a transcription factor which regulates a variety of cancer cellular physiological activities including cervical cancer. Sanguinarine (SNG) is a natural plant-derived benzophenanthridine alkaloid that possesses antitumor activities in several cancer cells. However, its anticancer effect on human cervical cancer cells and the underlying mechanisms have not been fully defined.

Methods

In this study, the inhibitory effect of SNG on the proliferation and growth of HeLa cell was detected by MTT assay. Next, cell cycle and apoptosis of HeLa cells was analyzed using Annexin-V/PI double staining and flow cytometry. Then, we measured intracellular ROS generation induced by SNG in HeLa cells by DCFH-DA (10 μM) staining, and the expression level of p-STAT3 and STAT3 was detected by Western blot. Finally, in order to study the effect of SNG on tumor growth in vivo, athymic nude mice were used in the vivo experiments.

Result

This study showed that SNG dose-dependently decreased the tumor cell proliferation and induced a marked increase in cell apoptosis in HeLa cells. Western blot analysis results revealed that SNG-induced antitumor effect might be mediated by STAT3 inhibition. SNG increased the expression of the proapoptotic protein Bax and reduced the expression of the antiapoptotic protein Bcl-2. We further found that SNG dose-dependently increased ROS level in Hela cells. Moreover, pretreatment with N-acetyl-l-cysteine, a scavenger of ROS, almost reversed the SNG-induced anticancer effect. In addition, SNG inhibited human cervical cancer xenograft growth without exhibiting toxicity in vivo.

Conclusion

Our findings highlight STAT3 as a promising therapeutic target. We also demonstrate that SNG is a novel anticancer drug for the treatment of cervical cancer.

Activity of manganese superoxide dismutase (MnSOD) as a predictor of radiation therapy outcome in patients with stage IIIB squamous cell carcinoma cervical cancer

BACKGROUND Radiation is a standard therapy for cervical cancer. Unfortunately, not all patients undergoing radiation achieve a complete response. Previous studies have shown that manganese superoxide dismutase (MnSOD) acts against free radicals generated by radiation in cancer cells thus predicting worse outcome in radiation therapy. This study was aimed to assess and evaluate whether MnSOD activity can be used as a predictor of radiation therapy responses in patients with stage IIIB squamous cell carcinoma (SCC). METHODS A comparative cross-sectional study was conducted in the Gynecology Oncology Division, Department of Obstetrics and Gynecology, Faculty of Medicine, Universitas Indonesia, Cipto Mangunkusumo Hospital, Jakarta. The database from previous research was analyzed to identify positive and negative response samples. Measurement of MnSOD activity was done using spectrophotometry based on the McCord and Fridovich method using RanSOD® kit. The comparative data were obtained and then analyzed. RESULTS Among 76 samples, 49 (61.8%) patients had positive responses and 27 (38.2%) had negative responses. It is shown in this study that higher MnSOD activity is related to worse radiotherapy outcome in stage IIIB cancer patients. The relative risk value of having a worse outcome with high MnSOD activity is 1.849 (1.075–3.178, 95% CI). CONCLUSIONS Stage IIIB squamous cell carcinoma patients with high MnSOD activity are at higher risk of having a negative radiation therapy response compared with patients without high MnSOD activity.

Senescence as a main mechanism of Ritonavir and Ritonavir-NO action against melanoma

The main focus of this study is exploring the effect and mechanism of two HIV-protease inhibitors: Ritonavir and Ritonavir-nitric oxide (Ritonavir-NO) on in vitro growth of melanoma cell lines. NO modification significantly improved the antitumor potential of Ritonavir, as the IC₅₀ values of Ritonavir-NO were approximately two times lower than IC₅₀ values of the parental compound. Our results showed for the first time, that both compounds induced senescence in primary and metastatic melanoma cell lines. This transformation was manifested as a change in cell morphology, enlargement of nuclei, increased cellular granulation, upregulation of β-galactosidase activity, lipofuscin granules appearance, higher production of reactive oxygen species and persistent inhibition of proliferation. The expression of p53, as one of the key regulators of senescence, was upregulated after 48 hours of Ritonavir-NO treatment only in metastatic B16F10 cells, ranking it as a late-response event. The development of senescent phenotype was consistent with the alteration of the cytoskeleton-as we observed diminished expression of vinculin, α-actin, and β-tubulin. Permanent inhibition of S6 protein by Ritonavir-NO, but not Ritonavir, could be responsible for a stronger antiproliferative potential of the NO-modified compound. Taken together, induction of senescent phenotype may provide an excellent platform for developing therapeutic approaches based on selective killing of senescent cells.

Effects of repurposed drug candidates nitroxoline and nelfinavir as single agents or in combination with erlotinib in pancreatic cancer cells

Background

Pancreatic cancer (PC) is the fourth most common cause of cancer death. Combination therapies with classical chemotherapeutic agents improved treatment of advanced PC at the cost of a relevant toxicity, but the 5-year survival rate remains below 5%. Consequently, new therapeutic options for this disease are urgently needed. In this study, we explored the effect of two repurposed drug candidates nelfinavir and nitroxoline, approved for non-anticancer human use, in PC cell lines. Nelfinavir and nitroxoline were tested as single agents, or in combinations with or without erlotinib, a targeted drug approved for PC treatment.

Methods

The effects of the drugs on the viability of AsPC-1, Capan-2 and BxPC-3 PC cell lines were assessed by MTT. The impact of the treatments on cell cycle distribution and apoptosis was analyzed by flow cytometry. The effects of treatments on proteins relevant in cell cycle regulation and apoptosis were evaluated by western blot. Self-renewal capacity of PC cell lines after drug treatments was assessed using a clonogenic assay.

Results

When used as single agents, nelfinavir and nitroxoline decreased viability, affected cell cycle and reduced the expression of relevant cell cycle proteins. The effects on apoptosis were variable among PC cell lines. Moreover, these agents drastically impaired clonogenic activity of the three PC cell lines. Combinations of nelfinavir and nitroxoline, with or without erlotinib, resulted in dose- and cell-dependent synergistic effects on cell viability. These effects were paralleled by cell cycle alterations and more consistent apoptosis induction as compared to single agents. Treatments with drug combinations induced drastic impairment of clonogenic activity in the three cell lines.

Conclusions

This study shows that two non-antitumor drugs, nelfinavir and nitroxoline, as single agents or in combination have antitumor effects that appear comparable, or in some case more pronounced than those of erlotinib in three PC cell lines. Our results support repurposing of these approved drugs as single agents or in combination for PC treatment.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0904-2) contains supplementary material, which is available to authorized users.

Withaferin A induces apoptosis by ROS-dependent mitochondrial dysfunction in human colorectal cancer cells

Withaferin A (WA) is an active steroidal lactone derived from the herbal plant Withania somnifera, which exhibits antitumor activity with reactive oxygen species (ROS) modulating in a variety of cancer models, such as breast cancer, lung cancer and pancreatic cancer. However, to the best of our knowledge, the direct effect and mechanism of WA on CRC cells has not been previously determined. The present study investigated the anti-tumor effects of WA on CRC cells in vitro, and explored the mechanisms of action. The flow cytometry was applied for detecting the accumulation of ROS with the treatment of withaferin A. We performed the flow cytometry and western blot to evaluate the withaferin A induced apoptosis and cell cycle arrest in human colon cancer cells. And to verify the ROS accumulation induced mitochondrial dysfunction after the treatment of withaferin A, fluorescence microscope and western blot were applied. WA exerted a dose-dependent cytotoxic effect on HCT-116 and RKO cells. The effect was associated with ROS-mediated cell cycle arrest and the expression of apoptotic proteins. In addition, WA promoted ROS production and decreased mitochondrial membrane potential accompanying with mitochondrial dysfunction. Taken together, these results strongly indicated that WA directly inhibits cell growth and induces apoptosis in CRC cells through ROS-mediated mitochondrial dysfunction and JNKs pathway, and WA may be a promising potential candidate for therapeutic application of CRC.

Antineoplastic effects of CPPTL via the ROS/JNK pathway in acute myeloid leukemia

Drug resistance and human leukocyte antigen (HLA) matching limit conventional treatment of acute myeloid leukemia (AML). Although several small molecule drugs are clinically used, single drug administration is not sufficient to cure AML, which has a high molecular diversity. Metabolic homeostasis plays a key role in determining cellular fate. Appropriate levels of reactive oxygen species (ROS) maintain the redox system balance, and excessive amounts of ROS cause oxidative damage, thus providing a strategy to eliminate cancer cells. CPPTL is a novel analogue of parthenolide that exhibited significant cytotoxicity to AML cells in vitro and induced apoptosis in a dose-dependent manner. Additionally, CPPTL's prodrug DMA-CPPTL decreased the burden of AML engraftment and prolonged survival in a mouse model administered human primary AML cells in vivo. CPPTL induced apoptosis of AML cells by stimulating ROS production, and accumulation of ROS then activated the JNK pathway, thereby promoting mitochondrial damage. These results demonstrated that CPPTL effectively eradicated AML cells in vitro and in vivo and suggested that CPPTL may be a novel candidate for auxiliary AML therapy.

Silkworm Pupa Protein Hydrolysate Induces Mitochondria-Dependent Apoptosis and S Phase Cell Cycle Arrest in Human Gastric Cancer SGC-7901 Cells

Silkworm pupae (Bombyx mori) are a high-protein nutrition source consumed in China since more than 2 thousand years ago. Recent studies revealed that silkworm pupae have therapeutic benefits to treat many diseases. However, the ability of the compounds of silkworm pupae to inhibit tumourigenesis remains to be elucidated. Here, we separated the protein of silkworm pupae and performed alcalase hydrolysis. Silkworm pupa protein hydrolysate (SPPH) can specifically inhibit the proliferation and provoke abnormal morphologic features of human gastric cancer cells SGC-7901 in a dose- and time-dependent manner. Moreover, flow cytometry indicated that SPPH can induce apoptosis and arrest the cell-cycle in S phase. Furthermore, SPPH was shown to provoke accumulation of reactive oxygen species (ROS) and depolarization of mitochondrial membrane potential. Western blotting analysis indicated that SPPH inhibited Bcl-2 expression and promoted Bax expression, and subsequently induced apoptosis-inducing factor and cytochrome C release, which led to the activation of initiator caspase-9 and executioner caspase-3, cleavage of poly (ADP-ribose) polymerase (PARP), eventually caused cell apoptosis. Moreover, SPPH-induced S-phase arrest was mediated by up-regulating the expression of E2F1 and down-regulating those of cyclin E, CDK2 and cyclin A2. Transcriptome sequencing and gene set enrichment analysis (GSEA) also revealed that SPPH treatment could affect gene expression and pathway regulation related to tumourigenesis, apoptosis and cell cycle. In summary, our results suggest that SPPH could specifically suppress cell growth of SGC-7901 through an intrinsic apoptotic pathway, ROS accumulation and cell cycle arrest, and silkworm pupae have a potential to become a source of anticancer agents in the future.

Identification of lncRNAs by microarray analysis reveals the potential role of lncRNAs in cervical cancer pathogenesis

Long non-coding RNAs (lncRNAs) have been acknowledged to serve a significant role in cancer biology and abnormal expression in tumors is frequently observed. However, their mechanisms in cervical cancer remain unclear. With a genome-wide analysis of lncRNA expression in cervical cancer tissues, the present study aimed to identify lncRNA targets for the further study of cervical cancer. To elucidate the specific role of lncRNAs in the pathogenesis of this type of cancer, 6 cervical cancer samples paired with normal cervical tissues were obtained. Expression profiles of lncRNAs and mRNAs were constructed through microarray analysis and confirmed by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) methods. Gene Ontology and pathway enrichment analyses were performed with computational methods. On the basis of correlations between the differential expression levels of lncRNAs and mRNAs, a coding-non-coding gene co-expression network (CNC network) was established. The differential expression of 5,844 lncRNAs and 4,436 mRNAs were discovered in cervical cancer samples compared with normal cervical tissues. Among the differentially expressed lncRNAs, 14 were chosen at random and validated by RT-qPCR; the majority of the results measured were consistent with the microarray results. Furthermore, the lncRNA ENST00000551152 was found to be upregulated and TCO. NS_00001368 lncRNA was downregulated in cervical cancer cell lines. The CNC network included 592 network nodes and 934 associations between 12 lncRNAs and 580 protein-coding genes, indicating that one lncRNA could act on a maximum of 141 coding genes, and that one coding gene may corresponded with a maximum of 5 lncRNAs. Overall, the present study has provided a complete expression profile of lncRNAs and mRNAs in cervical cancer, which may now be used to establish a solid foundation for cervical cancer research. These results may provide significant information for improving the understanding of the pathogenesis of cervical cancer and indicate potential therapeutic targets.

Cervical cancer risk and impact of Pap-based screening in HIV-positive women on antiretroviral therapy in Johannesburg, South Africa

Data on invasive cervical cancer (ICC) incidence in HIV-positive women and the effect of cervical cancer screening in sub-Saharan Africa are scarce. We estimated i) ICC incidence rates in women (≥18 years) who initiated antiretroviral therapy (ART) at the Themba Lethu Clinic (TLC) in Johannesburg, South Africa, between 2004 and 2011 and ii) the effect of a Pap-based screening program. We included 10,640 women; median age at ART initiation: 35 years [interquartile range (IQR) 30-42], median CD4 count at ART initiation: 113 cells/µL (IQR 46-184). During 27,257 person-years (pys), 138 women were diagnosed with ICC; overall incidence rate: 506/100,000 pys [95% confidence interval (CI) 428-598]. The ICC incidence rate was highest (615/100,000 pys) in women who initiated ART before cervical cancer screening became available in 04/2005 and was lowest (260/100,000 pys) in women who initiated ART from 01/2009 onward when the cervical cancer screening program and access to treatment of cervical lesions was expanded [adjusted hazard ratio (aHR) 0.42, 95% CI 0.20-0.87]. Advanced HIV/AIDS stage (4 versus 1, aHR 1.95, 95% CI 1.17-3.24) and middle age at ART initiation (36-45 versus 18-25 years, aHR 2.51, 95% CI 1.07-5.88) were risk factors for ICC. The ICC incidence rate substantially decreased with the implementation of a Pap-based screening program and improved access to treatment of cervical lesions. However, the risk of developing ICC after ART initiation remained high. To inform and improve ICC prevention and care for HIV-positive women in sub-Saharan Africa, implementation and monitoring of cervical cancer screening programs are essential.

Drug repurposing in cancer

Cancer is a major health issue worldwide, and the global burden of cancer is expected to increase in the coming years. Whereas the limited success with current therapies has driven huge investments into drug development, the average number of FDA approvals per year has declined since the 1990s. This unmet need for more effective anti-cancer drugs has sparked a growing interest for drug repurposing, i.e. using drugs already approved for other indications to treat cancer. As such, data both from pre-clinical experiments, clinical trials and observational studies have demonstrated anti-tumor efficacy for compounds within a wide range of drug classes other than cancer. Whereas some of them induce cancer cell death or suppress various aspects of cancer cell behavior in established tumors, others may prevent cancer development. Here, we provide an overview of promising candidates for drug repurposing in cancer, as well as studies describing the biological mechanisms underlying their anti-neoplastic effects.

The HIV protease inhibitor, nelfinavir, as a novel therapeutic approach for the treatment of refractory pediatric leukemia

PURPOSE

Refractory pediatric leukemia remains one of the leading causes of death in children. Intensification of current chemotherapy regimens to improve the outcome in these children is often limited by the effects of drug resistance and cumulative toxicity. Hence, the search for newer agents and novel therapeutic approaches are urgently needed to formulate the next-generation early-phase clinical trials for these patients.

MATERIALS AND METHODS

A comprehensive library of antimicrobials, including eight HIV protease inhibitors (nelfinavir [NFV], saquinavir, indinavir, ritonavir, amprenavir, atazanavir, lopinavir, and darunavir), was tested against a panel of pediatric leukemia cells by in vitro growth inhibition studies. Detailed target modulation studies were carried out by Western blot analyses. In addition, drug synergy experiments with conventional and novel antitumor agents were completed to identify effective treatment regimens for future clinical trials.

RESULTS

Several of the HIV protease inhibitors showed cytotoxicity at physiologically relevant concentrations (half-maximal inhibitory concentration values ranging from 1-24 µM). In particular, NFV was found to exhibit the most potent antileukemic properties across all cell lines tested. Mechanistic studies show that NFV leads to the induction of autophagy and apoptosis possibly through the induction of endoplasmic reticulum stress. Furthermore, interference with cell signaling pathways, including Akt and mTOR, was also noted. Finally, drug combination studies have identified agents with potential for synergy with NFV in its antileukemic activity. These include JQ1 (BET inhibitor), AT101 (Bcl-2 family inhibitor), and sunitinib (TK inhibitor).

CONCLUSION

Here, we show data demonstrating the potential of a previously unexplored group of drugs to address an unmet therapeutic need in pediatric oncology. The data presented provide preclinical supportive evidence and rationale for future studies of these agents for refractory leukemia in children.

Cellular Redox Profiling Using High-content Microscopy

Reactive oxygen species (ROS) regulate essential cellular processes including gene expression, migration, differentiation and proliferation. However, excessive ROS levels induce a state of oxidative stress, which is accompanied by irreversible oxidative damage to DNA, lipids and proteins. Thus, quantification of ROS provides a direct proxy for cellular health condition. Since mitochondria are among the major cellular sources and targets of ROS, joint analysis of mitochondrial function and ROS production in the same cells is crucial for better understanding the interconnection in pathophysiological conditions. Therefore, a high-content microscopy-based strategy was developed for simultaneous quantification of intracellular ROS levels, mitochondrial membrane potential (ΔΨm) and mitochondrial morphology. It is based on automated widefield fluorescence microscopy and image analysis of living adherent cells, grown in multi-well plates, and stained with the cell-permeable fluorescent reporter molecules CM-H2DCFDA (ROS) and TMRM (ΔΨm and mitochondrial morphology). In contrast with fluorimetry or flow-cytometry, this strategy allows quantification of subcellular parameters at the level of the individual cell with high spatiotemporal resolution, both before and after experimental stimulation. Importantly, the image-based nature of the method allows extracting morphological parameters in addition to signal intensities. The combined feature set is used for explorative and statistical multivariate data analysis to detect differences between subpopulations, cell types and/or treatments. Here, a detailed description of the assay is provided, along with an example experiment that proves its potential for unambiguous discrimination between cellular states after chemical perturbation.

Combining metformin and nelfinavir exhibits synergistic effects against the growth of human cervical cancer cells and xenograft in nude mice

Human cervical cancer is the fourth most common carcinoma in women worldwide. However, the emergence of drug resistance calls for continuously developing new anticancer drugs and combination chemotherapy regimens. The present study aimed to investigate the anti-cervical cancer effects of metformin, a first-line therapeutic drug for type 2 diabetes mellitus, and nelfinavir, an HIV protease inhibitor, when used alone or in combination. We found that both metformin and nelfinavir, when used alone, were moderately effective in inhibiting proliferation, inducing apoptosis and suppressing migration and invasion of human cervical cell lines HeLa, SiHa and CaSki. When used in combination, these two drugs acted synergistically to inhibit the growth of human cervical cancer cells in vitro and cervical cancer cell xenograft in vivo in nude mice, and suppress cervical cancer cell migration and invasion. The protein expression of phosphoinositide 3-kinase catalytic subunit PI3K(p110α), which can promote tumor growth, was remarkably downregulated, while the tumor suppressor proteins p53 and p21 were substantially upregulated following the combinational treatment in vitro and in vivo. These results suggest that clinical use of metformin and nelfinavir in combination is expected to have synergistic antitumor efficacy and significant potential for the treatment of human cervical cancer.

Bigelovin triggered apoptosis in colorectal cancer in vitro and in vivo via upregulating death receptor 5 and reactive oxidative species

Colorectal cancer (CRC) is the third most prevalent cancer and the third highest cancer-related mortality in the United States. Bigelovin, a sesquiterpene lactone isolated from Inula helianthus aquatica, has been proven to induce apoptosis and exhibit anti-inflammatory and anti-angiogenic activities. However, the effects of bigelovin on CRC and underlying mechanisms have not been explored. The present study demonstrated that bigelovin exhibited potent anti-tumor activities against CRC in vitro and in vivo. Bigelovin suppressed cell proliferation and colony formation and induced apoptosis in human colorectal cancer HT-29 and HCT 116 cells in vitro. Results also revealed that bigelovin activated caspases, caused the G2/M cell cycle arrest and induced DNA damage through up-regulation of death receptor (DR) 5 and increase of ROS. In HCT 116 xenograft model, bigelovin treatment resulted in suppression of tumor growth. Bigelovin at 20 mg/kg showed more significant tumor suppression and less side effects than conventional FOLFOX (containing folinic acid, 5-fluorouracil and oxaliplatin) treatment. In addition, in vivo data confirmed that anti-tumor activity of bigelovin in CRC was through induction of apoptosis by up-regulating DR5 and increasing ROS. In conclusion, these results strongly suggested that bigelovin has potential to be developed as therapeutic agent for CRC patients.

HIV-protease inhibitors for the treatment of cancer: Repositioning HIV protease inhibitors while developing more potent NO-hybridized derivatives?

The possible use of HIV protease inhibitors (HIV-PI) as new therapeutic option for the treatment of cancer primarily originated from their success in treating HIV-related Kaposi's sarcoma (KS). While these findings were initially attributed to immune reconstitution and better control of oncogenic viral infections, the number of reports on solid tumors, KS, lymphoma, fibrosarcoma, multiple myeloma and prostate cancer suggest other mechanisms for the anti-neoplastic activity of PIs. However, a major drawback for the possible adoption of HIV-PIs in the therapy of cancer relies on their relatively weak anticancer potency and important side effects. This has propelled several groups to generate derivatives of HIV-PIs for anticancer use, through modifications such as attachment of different moieties, ligands and transporters, including saquinavir-loaded folic acid conjugated nanoparticles and nitric oxide (NO) derivatives of HIV-PIs. In this article, we discuss the current preclinical and clinical evidences for the potential use of HIV-PIs, and of novel derivatives, such as saquinavir-NO in the treatment of cancer.

Induction of DNA damage and apoptosis in human leukemia cells by efavirenz

As part of the efforts to drug repurposing, some HIV drugs have recently been identified to exert anticancer effects. Selected nucleoside analogues of nucleosidic reverse-transcriptase inhibitors (NRTIs) have been shown to interfere with RNA transcription of HI viruses as well as with the replication of DNA in cancer cells. Non-nucleosidic reverse transcriptase inhibitors (NNRTIs) are believed to have less effects on human DNA replication and, thus, on cancer cell proliferation. Assessment of the effect of the NNRTI efavirenz in human cancer cells, however, revealed a high sensitivity of leukemia cells to this agent at pharmacologically relevant concentrations of less than 10 µg/ml. Cell death induced by efavirenz was caused by apoptosis, as shown by FACScan analysis (Annexin binding) and western blot analysis (cleavage of caspases and PARP). Western blot analyses also revealed a pronounced activation and phosphorylation of the DNA damage marker proteins p53, chk2 and H2AX, indicating DNA replication and genomic integrity as primary targets of efavirenz in leukemia cells.

Curcumin analog EF24 induces apoptosis via ROS-dependent mitochondrial dysfunction in human colorectal cancer cells

PURPOSE

Colorectal cancer is the most commonly diagnosed malignancy with high mortality rates worldwide. Improved therapeutic strategies with minimal adverse side effects are urgently needed. In this study, the anti-tumor effects of EF24, a novel analog of the natural compound curcumin, were evaluated in colorectal cancer cells.

METHODS

The anti-tumor activity of EF24 on human colon cancer lines (HCT-116, SW-620, and HT-29) was determined by measures of cell cycle arrest, apoptosis, and mitochondrial function. The contribution of ROS in the EF24-induced anti-tumor activity was evaluated by measures of H₂O₂ and pretreatment with an ROS scavenger, NAC.

RESULTS

The findings indicated that EF24 treatment dose-dependently inhibited cell viability and caused cell cycle arrest at G2/M phase in all the tested colon cancer cell lines. Furthermore, we demonstrated that EF24 treatment induced apoptosis effectively via enhancing intracellular accumulation of ROS in both HCT-116 and SW-620 cells, but with moderate effects in HT-29 cells. We found that EF24 treatment decreased the mitochondrial membrane potential in the colon cancer cells, leading to the release of mitochondrial cytochrome c. Also, EF24 induced activation of caspases 9 and 3, causing decreased Bcl-2 protein expression and Bcl-2/Bax ratio. Pretreatment with NAC, a ROS scavenger, abrogated the EF24-induced cell death, apoptosis, cell cycle arrest, and mitochondrial dysfunction, suggesting an upstream ROS generation which was responsible for the anticancer effects of EF24.

CONCLUSIONS

Our findings support an anticancer mechanism by which EF24 enhanced ROS accumulation in colon cancer cells, thereby resulting in mitochondrial membrane collapse and activated intrinsic apoptotic signaling. Thus, EF24 could be a potential candidate for therapeutic application of colon cancer.

Integrated High-Content Quantification of Intracellular ROS Levels and Mitochondrial Morphofunction

Oxidative stress arises from an imbalance between the production of reactive oxygen species (ROS) and their removal by cellular antioxidant systems. Especially under pathological conditions, mitochondria constitute a relevant source of cellular ROS. These organelles harbor the electron transport chain, bringing electrons in close vicinity to molecular oxygen. Although a full understanding is still lacking, intracellular ROS generation and mitochondrial function are also linked to changes in mitochondrial morphology. To study the intricate relationships between the different factors that govern cellular redox balance in living cells, we have developed a high-content microscopy-based strategy for simultaneous quantification of intracellular ROS levels and mitochondrial morphofunction. Here, we summarize the principles of intracellular ROS generation and removal, and we explain the major considerations for performing quantitative microscopy analyses of ROS and mitochondrial morphofunction in living cells. Next, we describe our workflow, and finally, we illustrate that a multiparametric readout enables the unambiguous classification of chemically perturbed cells as well as laminopathy patient cells.

Oxidative Stress Mediates the Antiproliferative Effects of Nelfinavir in Breast Cancer Cells

The discovery of the anti-proliferative activity of nelfinavir in HIV-free models has encouraged its investigation as anticancer drug. Although the molecular mechanism by which nelfinavir exerts antitumor activity is still unknown, its effects have been related to Akt inhibition. Here we tested the effects of nelfinavir on cell proliferation, viability and death in two human breast cancer cell lines and in human normal primary breast cells. To identify the mechanism of action of nelfinavir in breast cancer, we evaluated the involvement of the Akt pathway as well as the effects of nelfinavir on reactive oxygen species (ROS) production and ROS-related enzymes activities. Nelfinavir reduced breast cancer cell viability by inducing apoptosis and necrosis, without affecting primary normal breast cells. The antitumor activity of nelfinavir was related to alterations of the cell redox state, coupled with an increase of intracellular ROS production limited to cancer cells. Nelfinavir treated tumor cells also displayed a downregulation of the Akt pathway due to disruption of the Akt-HSP90 complex, and subsequent degradation of Akt. These effects resulted to be ROS dependent, suggesting that ROS production is the primary step of nelfinavir anticancer activity. The analysis of ROS-producers and ROS-detoxifying enzymes revealed that nelfinavir-mediated ROS production was strictly linked to flavoenzymes activation. We demonstrated that ROS enhancement represents the main molecular mechanism required to induce cell death by nelfinavir in breast cancer cells, thus supporting the development of new and more potent oxidizing molecules for breast cancer therapy.

Nelfinavir is effective against human cervical cancer cells in vivo: a potential treatment modality in resource-limited settings

Objective

The standard treatment for cervical cancer in developed countries includes surgery and chemoradiation, with standard of care lagging in developing countries. Even in the former case, treatment frequently yields recalcitrant tumors and women succumb to disease. Here we examine the impact of nelfinavir, an off-patent viral protease inhibitor, which has shown promise as an antineoplastic agent.

Methods

We evaluated the morphological and proliferative effects of the autophagy-stressing drug nelfinavir in normal and cisplatin-resistant cervical cancer cells. Immunofluorescent validation of autophagy markers was performed and the impact of nelfinavir in an in vivo model of tumor growth was determined.

Results

Nelfinavir exhibits cytotoxicity against both cisplatin-sensitive and -resistant ME-180 human cervical cancer cells in vitro and in vivo. Immunoblotting and immunofluorescence showed an expression of the autophagy marker LC3-II in response to nelfinavir treatment.

Conclusion

Nelfinavir, now available as an inexpensive generic orally dosed agent (Nelvir), is cytotoxic against cervical cancer cells. It acts by burdening the autophagy pathway to impair tumor cell survival and a modest induction of apoptosis. While further studies are needed to elucidate the optimal method of application of nelfinavir, it may represent an appealing global option for the treatment of cervical cancer.

Piperlongumine as a direct TrxR1 inhibitor with suppressive activity against gastric cancer

Piperlongumine (PL), a natural alkaloid isolated from the fruit of long pepper, is known to selectively kill tumor cells while sparing their normal counterparts. However, the cellular target and potent anticancer efficacy of PL in numerous types of human cancer cells have not been fully defined. We report here that PL may interact with the thioredoxin reductase 1 (TrxR1), an important selenocysteine (Sec)-containing antioxidant enzyme, to induce reactive oxygen species (ROS)-mediated apoptosis in human gastric cancer cells. By inhibiting TrxR1 activity and increasing intracellular ROS levels, PL induces a lethal endoplasmic reticulum stress and mitochondrial dysfunction in human gastric cancer cells. Importantly, knockdown of TrxR1 sensitizes cells to PL treatment, and PL displays synergistic lethality with GSH inhibitors (BSO and Erastin) against gastric cancer cells. In vivo, PL treatment markedly reduces the TrxR1 activity and tumor cell burden. Remarkably, TrxR1 was significantly overexpressed in gastric cancer cell lines and human gastric cancer tissues. Targeting TrxR1 with PL thus discloses a previously unrecognized mechanism underlying the biological activity of PL and provides an in-depth insight into the action of PL in the treatment of gastric cancer.

Alantolactone induces apoptosis of human cervical cancer cells via reactive oxygen species generation, glutathione depletion and inhibition of the Bcl-2/Bax signaling pathway

Alantolactone is the active ingredient in frankincense, and is extracted from the dry root of elecampane. It has a wide variety of uses, including as an insect repellent, antibacterial, antidiuretic, analgesic and anticancer agent. In addition, alantolactone induces apoptosis of human cervical cancer cells, however, its mechanism of action remains to be elucidated. Therefore, the present study investigated whether alantolactone was able to induce apoptosis of human cervical cancer cells, and its potential mechanisms of action were analyzed. Treatment of HeLa cells with alantolactone (0, 10, 20, 30, 40, 50 and 60 µM) for 12 h significantly inhibited growth in a dose-dependent manner. Cells treated with 30 µM of alantolactone for 0, 3, 6 and 12 h demonstrated marked induction of apoptosis in a time-dependent manner. Treatment of HeLa cells with 30 µM of alantolactone for 0, 3, 6 and 12 h significantly induced the generation of reactive oxygen species (ROS) and inhibited glutathione (GSH) production in HeLa cells in a dose-dependent manner. Alantolactone additionally markedly inhibited the Bcl-2/Bax signaling pathway in HeLa cells. Therefore, administration of alantolactone induced apoptosis of human cervical cancer cells via ROS generation, GSH depletion and inhibition of the Bcl-2/Bax signaling pathway.

A Bowman-Birk inhibitor induces apoptosis in human breast adenocarcinoma through mitochondrial impairment and oxidative damage following proteasome 20S inhibition

Proteasome inhibitors are emerging as a new class of chemopreventive agents and have gained huge importance as potential pharmacological tools in breast cancer treatment. Improved understanding of the role played by proteases and their specific inhibitors in humans offers novel and challenging opportunities for preventive and therapeutic intervention. In this study, we demonstrated that the Bowman-Birk protease inhibitor from Vigna unguiculata seeds, named black-eyed pea trypsin/chymotrypsin Inhibitor (BTCI), potently suppresses human breast adenocarcinoma cell viability by inhibiting the activity of proteasome 20S. BTCI induced a negative growth effect against a panel of breast cancer cells, with a concomitant cytostatic effect at the G2/M phase of the cell cycle and an increase in apoptosis, as observed by an augmented number of cells at the sub-G1 phase and annexin V-fluorescin isothiocyanate (FITC)/propidium iodide (PI) staining. In contrast, BTCI exhibited no cytotoxic effect on normal mammary epithelial cells. Moreover, the increased levels of intracellular reactive oxygen species (ROS) and changes in the mitochondrial membrane potential in cells treated with BTCI indicated mitochondrial damage as a crucial cellular event responsible for the apoptotic process. The higher activity of caspase in tumoral cells treated with BTCI in comparison with untreated cells suggests that BTCI induces apoptosis in a caspase-dependent manner. BTCI affected NF-kB target gene expression in both non invasive and invasive breast cancer cell lines, with the effect highly pronounced in the invasive cells. An increased expression of interleukin-8 (IL-8) in both cell lines was also observed. Taken together, these results suggest that BTCI promotes apoptosis through ROS-induced mitochondrial damage following proteasome inhibition. These findings highlight the pharmacological potential and benefit of BTCI in breast cancer treatment.

Everything Old Is New Again: Using Nelfinavir to Radiosensitize Rectal Cancer

Repurposing agents approved for other indications to radiosensitize tumors may be advantageous. The study by Hill and colleagues utilizes nelfinavir, an HIV protease inhibitor (PI), in combination with radiotherapy in rectal cancer in a prospective study. This combination may improve tumor perfusion and regression compared with radiotherapy alone.