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Aims: Hypoxia is believed to be one of the key components contributing to the clinical resistance of cancer therapies. Alternative strategies are under investigation to overcome this resistance and the oncolytic virus stands amongst the others. Newcastle disease virus (NDV) has been demonstrated to possess oncolytic activity against cancer cells. The present study investigated the effects of oncolytic NDV strain AF2240 and V4-UPM on osteosarcoma cells (Saos-2) under normoxic and hypoxic conditions. Methodology and results: Results showed that the NDV strain AF2240 and V4-UPM could infect and kill normoxic and hypoxic Saos-2 cells equally well by inducing hypoxia-independent apoptosis, and S-phase cell cycle arrest under the microscopy examination, cell viability assay, Annexin V apoptosis assay and cell cycle analysis experiments. However, the Velogenic NDV strain AF2240 excelled over the lentogenic NDV V4-UPM with increased oncolytic effects in Saos-2 cells. Conclusion, significance and impact of study: In a nutshell, normoxia or hypoxia microenvironment has little effect on NDV-induced oncolysis of Saos-2 cancer cells which poses as a potential agent for the treatment of resistant cancer. [ABSTRACT FROM AUTHOR]

Poly(ADP-ribose) polymerase (PARP) are critical DNA repair enzymes that are activated as part of the DNA damage response (DDR). Although inhibitors of PARP (PARPi) have emerged as small molecule drugs and have shown promising therapeutic effects, PARPi used as single agents are clinically limited to patients with mutations in germline breast cancer susceptibility gene (BRCA). Thus, novel PARPi combination strategies may expand their usage and combat drug resistance. In recent years, ruthenium polypyridyl complexes (RPCs) have emerged as promising anti-cancer candidates due to their attractive DNA binding properties and distinct mechanisms of action. Previously, we reported the rational combination of the RPC DNA replication inhibitor [Ru(dppz)2(PIP)]2+ (dppz = dipyrido[3,2-a:2′,3′-c]phenazine, PIP = 2-(phenyl)-imidazo[4,5-f][1,10]phenanthroline), "Ru-PIP", with the PARPi Olaparib in breast cancer cells. Here, we expand upon this work and examine the combination of Ru-PIP with Olaparib for synergy in lung cancer cells, including in 3D lung cancer spheroids, to further elucidate mechanisms of synergy and additionally assess toxicity in a zebrafish embryo model. Compared to single agents alone, Ru-PIP and Olaparib synergy was observed in both A549 and H1975 lung cancer cell lines with mild impact on normal lung fibroblast MRC5 cells. Employing the A549 cell line, synergy was confirmed by loss in clonogenic potential and reduced migration properties. Mechanistic studies indicated that synergy is accompanied by increased double-strand break (DSB) DNA damage and reactive oxygen species (ROS) levels which subsequently lead to cell death via apoptosis. Moreover, the identified combination was successfully able to inhibit the growth of A549 lung cancer spheroids and acute zebrafish embryos toxicity studies revealed that this combination showed reduced toxicity compared to single-agent Ru-PIP. [ABSTRACT FROM AUTHOR]

Human respiratory syncytial virus (RSV) is one of the major causes of childhood acute lower respiratory tract infection worldwide. Autophagy is an intracellular pathway involved in nutrient recycling. Recently, autophagy has been reported to play a role in regulating host cytokine response to several viruses, including vesicular stomatitis virus and human immunodeficiency virus. Previous in vivo studies using mouse model has shown that inhibition of autophagy reduces RSV-induced cytokine production. However, the role of autophagy in modulating RSV-induced cytokine response in human cells has not been reported. We investigated the role of autophagy in regulating the production of the cytokines C-X-C motif ligand 8 (CXCL8) and C-C motif ligand 5 (CCL5), in RSV-infected human bronchial epithelium BEAS-2B cells. Fluorescent microscopic analysis showed that RSV infection induced autophagosome formation in BEAS-2B cells. This autophagy inducing ability of RSV was further confirmed by flow cytometry. The effects of pharmacological inhibition of autophagy by SAR405 or chloroquine on cell death and cytokine release were quantified using lactate dehydrogenase assay and enzyme-linked immunosorbent assay (ELISA), respectively. We found that SAR405 or chloroquine did not cause cell death. Importantly, ELISA analysis showed that pharmacological inhibition of autophagy by SAR405 or chloroquine did not affect the productions of both CXCL5 and CXCL8. In contrast to the previous studies using mouse model, our data suggest that pharmacological inhibition of autophagy may not be a suitable strategy in controlling RSV-induced airway inflammation. [ABSTRACT FROM AUTHOR]

Colorectal cancer (CRC) is one of the most common malignancies. In recent decades, early diagnosis and conventional therapies have resulted in a significant reduction in mortality. However, late stage metastatic disease still has very limited effective treatment options. There is a growing interest in using viruses to help target therapies to tumour sites. In recent years the evolution of immunotherapy has emphasised the importance of directing the immune system to eliminate tumour cells; we aim to give a state-of-the-art over-view of the diverse viruses that have been investigated as potential oncolytic agents for the treatment of CRC. [ABSTRACT FROM AUTHOR]

Enadenotucirev (EnAd) is a group B oncolytic adenovirus developed for systemic delivery and currently undergoing clinical evaluation for advanced cancer therapy. For differentiated carcinomas, systemic delivery would likely expose virus particles to the basolateral surface of cancer cells rather than the apical surface encountered during natural infection. Here, we compare the ability of EnAd and adenovirus type-5 (Ad5) to infect polarised colorectal carcinoma cells from the apical or basolateral surfaces. Whereas Ad5 infection was more efficient via the apical than basolateral surface, EnAd readily infected cells from either surface. Progeny particles from EnAd were released preferentially via the apical surface for all cell lines and routes of infection. These data further support the utility of group B adenoviruses for systemic delivery and suggest that progeny virus are more likely to be released into the tumour rather than back through the basolateral surface into the blood stream. [ABSTRACT FROM AUTHOR]

The ruthenium polypyridyl complex [Ru(dppz)2PIP]2+ (dppz: dipyridophenazine, PIP: (2-(phenyl)-imidazo[4,5-f ][1,10]phenanthroline), or Ru-PIP, is a potential anticancer drug that acts by inhibiting DNA replication. Due to the poor dissolution of Ru-PIP in aqueous media, a drug delivery agent would be a useful approach to overcome its limited bioavailability. Mesoporous silica nanoparticles (MSNs) were synthesized via a co-condensation method by using a phenanthrolinium salt with a 16 carbon length chain (Phen-C16) as the template. Optimization of the synthesis conditions by Box–Behnken design (BBD) generated MSNs with high surface area response at 833.9 m2g−1. Ru-PIP was effectively entrapped in MSNs at 18.84%. Drug release profile analysis showed that Ru-PIP is gradually released, with a cumulative release percentage of approximately 50% at 72 h. The release kinetic profile implied that Ru-PIP was released from MSN by diffusion. The in vitro cytotoxicity of Ru-PIP, both free and MSN-encapsulated, was studied in Hela, A549, and T24 cancer cell lines. While treatment of Ru-PIP alone is moderately cytotoxic, encapsulated Ru-PIP exerted significant cytotoxicity upon all the cell lines, with half maximal inhibitory concentration (IC50) values determined by MTT (([3-(4,5-dimethylthiazol-2-yl)-2,5-dephenyltetrazolium bromide]) assay at 48 h exposure substantially decreasing from >30 µM to <10 µM as a result of MSN encapsulation. The mechanistic potential of cytotoxicity on cell cycle distribution showed an increase in G1/S phase populations in all three cell lines. The findings indicate that MSN is an ideal drug delivery agent, as it is able to sustainably release Ru-PIP by diffusion in a prolonged treatment period. [ABSTRACT FROM AUTHOR]

In the present study, we investigated the in-vitro anti-cancer potential of six diarylpentanoids against a panel of BRAF- and KRAS-mutated colorectal cancer cell lines including T84, SW620, LoVo, HT29, NCI-H508, RKO, and LS411N cells. Structure–activity relationship study suggested that the insertions of tetrahydro-4H-thiopyran-4-one and brominated phenyl moieties are essential for better cytotoxicity. Among the evaluated analogs, 2e has been identified as the lead compound due to its low IC50 values of approximately 1 µM across all cancer cell lines and high chemotherapeutic index of 7.1. Anti-proliferative studies on LoVo cells showed that 2e could inhibit cell proliferation and colony formations by inducing G2/M cell cycle arrest. Subsequent cell apoptosis assay confirmed that 2e is a Bcl-2 inhibitor that could induce intrinsic cell apoptosis by creating a cellular redox imbalance through its direct inhibition on the Bcl-2 protein. Further molecular docking studies revealed that the bromophenyl moieties of 2e could interact with the Bcl-2 surface pocket through hydrophobic interaction, while the tetrahydro-4H-thiopyran-4-one fragment could form additional Pi-sulfur and Pi-alkyl interactions in the same binding site. In all, the present results suggest that 2e could be a potent lead that deserves further modification and investigation in the development of a new Bcl-2 inhibitor. [ABSTRACT FROM AUTHOR]

In the present study, a series of nine stable 3,4,5-methoxylphenyl-containing asymmetrical diarylpentanoids, derivatives of curcuminoids, have been synthesized, characterized and evaluated for their in-vitro anti-cancer potential against a panel of BRAF- and KRAS-mutated colorectal cancer cell lines including T84, LoVo and SW620, HT29, RKO and NCI-H508, respectively. Structure-activity relationship study on cytotoxicity of tested compounds suggested that the presence of meta-hydroxyl and adjacent dimethoxyl groups are crucial for enhanced cytotoxicity of diarylpentanoids. Among the evaluated analogs, 8 has been identified as the lead compound due to its highest chemotherapeutic index of 9.9 and nano molar scale cytotoxicity against SW620 and RKO. Colonies formation and cell cycle analyses on 8 -treated RKO cells showed that 8 exhibits strong anti-proliferative activity by inducing G2/M-phase cell arrest. Subsequent flow cytometry based annexin-V and DCFHDA studies suggested that 8 could induce apoptosis through intracellular ROS-dependent pathway. Further Western blot studies confirmed that 8 has induced intrinsic apoptosis in RKO cells through the up-regulations of Bad and Bax pro-apoptotic proteins and down-regulations of Bcl-2 and Bcl-xL pro-survival proteins. In all, the present results suggest that 8 could be a potent lead which deserves further modification and investigation in the development of small molecule-based anti-colorectal cancer agents. [ABSTRACT FROM AUTHOR]

Introduction: Poly(ADP-ribose) polymerase (PARP) inhibitors (PARPi) target the key DNA repair enzymes of PARP and have emerged as small molecule drugs. Recently, ruthenium(II) polypyridyl complexes (RPCs) have shown promise as anticancer candidates due to their ability to form non-covalent (reversible) interactions with DNA. Previously, we have reported the RPC [Ru(dppz)2(PIP)]2+ (dppz = dipyrido[3,2-a:2',3'-c]phenazine, PIP = 2-(phenyl)-imidazo[ 4,5-f][1,10]phenanthroline), "Ru-PIP" induce replication stress in cancer cells by stalling the DNA replication fork progression. Therefore, the rational combination of Ru-PIP with PARPi may show synergistic activities in cancer cells. In the present study, we examine the combination of Ru-PIP with the most successful PARPi to date, Olaparib for synergy in lung cancer cells. We additionally assess toxicity of the identified combination in a zebrafish embryo model. Methods: A549 cells were treated with Ru-PIP or Olaparib single agents alone or in combination and MTT assay was carried out. Synergy was determined using Chou and Talalay combination index (CI) method in which C1 < 1 represents synergy and synergy was further confirmed using clonogenic survival assay. Further acute toxicity test of the identified synergy combination on zebrafish embryos was then carried out. Results: Ru-PIP and Olaparib synergy was observed in A549 lung cancer cell line. Synergy was confirmed by loss in clonogenic potential. Moreover, acute zebrafish embryos toxicity studies revealed that this combination showed reduced toxicity compared to single-agent Ru-PIP. Conclusion: We demonstrate that the identified synergistic Ru-PIP/Olaparib combination may potentially reduce side effects observed in single-agent therapy and thus, demonstrate new promising therapeutic strategy to combat cancer. [ABSTRACT FROM AUTHOR]

Introduction: The evaluation of drug effects in a 3D spheroids model can provide insight on the cytotoxicity and drug penetration. In addition, 3D spheroids often better recapitulate the tissue microenvironment in vivo as they mimic the complexity and heterogeneity of cellular organization in clinical tumors. Ruthenium (II) polypyridyl complexes (RPCs) have emerged as promising anticancer candidates due to their attractive DNA binding property. Inhibitors of poly(ADP-ribose) polymerase (PARP) are new small molecule drugs that show promising therapeutic effects. Previously, we have evaluated the rationale combination of the RPC [Ru(dppz)2(PIP)]2+ (dppz = dipyrido[3,2-a:2',3'-c] phenazine, PIP = 2-(phenyl)-imidazo[4,5-f][1,10]phenanthroline), "Ru-PIP" with PARP inhibitor Olaparib in 2D monolayer cell culture in which Ru-PIP/Olaparib synergy was shown. In the present study, we examine the identified synergistic Ru-PIP/Olaparib combination in 3D lung cancer spheroids to further elucidate synergy. Methods: A549 lung cancer spheroids were developed using hanging drop technique. Spheroids growth inhibition study and spheroids live/dead staining experiments were conducted to examine the cellular viability of the spheroids upon treated with Ru-PIP/Olaparib combination. Results: A549 cells formed spheroids that managed to grow in diameter in size and volume over 15 days, thereby qualifying them as a suitable 3D cell culture model. Our results show that the structural integrity of the A549 spheroids was lost after 12 days treatment with the combination, meanwhile single agents-treated spheroids remained structurally intact, although Ru-PIP single agent inhibited spheroids growth. Compared to single agents alone, the combination induced more cell death in A549 spheroids, as indicated by Calcein AM/PI staining. Conclusion: We demonstrate that the synergistic Ru-PIP/Olaparib combination is able to inhibit the growth of the more-resistant lung cancer spheroids model, showing promising therapeutic effects and merit further clinical assessment in vivo. [ABSTRACT FROM AUTHOR]

The discovery of tumour selective virus-mediated apoptosis marked the birth of an alternative cancer treatment in the form of oncolytic viruses. Even though, its oncolytic efficiency was demonstrated more than 50 years ago, safety concerns which resulted from mild to lethal side effects hampered the progress of oncolytic virus research. Since the classical oncolytic virus studies rely heavily on its natural oncolytic ability, virus manipulation was limited, thereby, restricted efforts to improve its safety. In order to circumvent such restriction, experiments involving non-human viruses such as the avian Newcastle disease virus (NDV) was conducted using cultured cells, animal models and human subjects. The corresponding reports on its significant tumour cytotoxicity along with impressive safety profile initiated immense research interest in the field of oncolytic NDV. The varying degree of oncolytic efficiency and virulency among NDV strains encouraged researchers from all around the world to experiment with their respective local NDV isolates in order to develop an oncolytic virus with desirable characteristics. Such desirable features include high tumour-killing ability, selectivity and low systemic cytotoxicity. The Malaysian field outbreak isolate, NDV strain AF2240, also currently, receives significant research attention. Apart from its high cytotoxicity against tumour cells, this strain also provided fundamental insight into NDV-mediated apoptosis mechanism which involves Bax protein recruitment as well as death receptor engagement. Studies on its ability to selectively induce apoptosis in tumour cells also resulted in a proposed p38 MAPK/NF-κB/IκBα pathway. The immunogenicity of AF2240 was also investigated through PBMC stimulation and macrophage infection. In addition, the enhanced oncolytic ability of this strain under hypoxic condition signifies its dynamic tumour tropism. This review is aimed to introduce and discuss the aforementioned details of the oncolytic AF2240 strain along with its current challenges which outlines the future research direction of this virus. [ABSTRACT FROM AUTHOR]