The role of Bcl-2 family members in tumorigenesis

Crude Methanol Extract of Rosin Gum Exhibits Specific Cytotoxicity against Human Breast Cancer Cells via Apoptosis Induction

BACKGROUND

Rosin (Colophony) is a natural resin derived from species of the pine family Pinaceae. It has wide industrial applications including printing inks, photocopying paper, adhesives and varnishes, soap and soda. Rosin and its derivatives are employed as ingredients in various pharmaceutical products such as ointments and plasters. Rosin-based products contain allergens that may exert some occupational health problems such as asthma and contact dermatitis.

OBJECTIVE

Our knowledge of the pharmaceutical and medicinal properties of rosin is limited. The current study aims at investigating the cytotoxic potential of Rosin-Derived Crude Methanolic Extract (RD-CME) and elucidation of its mode-of-action against breast cancer cells (MCF-7 and MDA-MB231).

METHODS

Crude methanol extract was prepared from rosin. Its phenolic contents were analyzed by Reversed- Phase High-Performance Liquid Chromatography (RP-HPLC). Antioxidant activity was evaluated by DPPH radical-scavenging assay. Antiproliferation activity against MCF-7 and MDA-MB231 cancerous cells was investigated by MTT assay; its potency compared with doxorubicin as positive control and specificity were assessed compared to two non-cancerous cell lines (BJ-1 and MCF-12F). Selected apoptosis protein markers were assayed by western blotting. Cell cycle analysis was performed by Annexin V-FITC/PI FACS assay.

RESULTS

RD-CME exhibited significant and selective cytotoxicity against the two tested breast cancer cells (MCF-7 and MDA-MB231) compared to normal cells as revealed by MTT assay. ELISA and western blotting indicated that the observed antiproliferative activity of RD-CME is mediated via the engagement of an intrinsic apoptosis signaling pathway, as judged by enhanced expression of key pro-apoptotic protein markers (p53, Bax and Casp 3) relative to vehicle solvent-treated MCF-7 control cells.

CONCLUSION

To our knowledge, this is the first report to investigate the medicinal anticancer and antioxidant potential of crude methanolic extract derived from colophony rosin. We provided evidence that RD-CME exhibits strong antioxidant and anticancer effects. The observed cytotoxic activity against MCF-7 is proposed to take place via G2/M cell cycle arrest and apoptosis. Colophony resin has a great potential to join the arsenal of plantderived natural anticancer drugs. Further thorough investigation of the potential cytotoxicity of RD-CME against various cancerous cell lines is required to assess the spectrum and potency of its novel activity.

Design, Synthesis, Anticancer Evaluation, Enzymatic Assays, and a Molecular Modeling Study of Novel Pyrazole-Indole Hybrids

The molecular hybridization concept has recently emerged as a powerful approach in drug discovery. A series of novel indole derivatives linked to the pyrazole moiety were designed and developed via a molecular hybridization protocol as antitumor agents. The target compounds (5a-j and 7a-e) were prepared by the reaction of 5-aminopyrazoles (1a-e) with N-substituted isatin (4a,b) and 1H-indole-3-carbaldehyde (6), respectively. All products were characterized via several analytical and spectroscopic techniques. Compounds (5a-j and 7a-e) were screened for their cytotoxicity activities in vitro against four human cancer types [human colorectal carcinoma (HCT-116), human breast adenocarcinoma (MCF-7), human liver carcinoma (HepG2), and human lung carcinoma (A549)] using the MTT assay. The obtained results showed that the newly synthesized compounds displayed good-to-excellent antitumor activity. For example, 5-((1H-indol-3-yl)methyleneamino)-N-phenyl-3-(phenylamino)-1H-pyrazole-4-carboxamide (7a) and 5-((1H-indol-3-yl)methyleneamino)-3-(phenylamino)-N-(4-methylphenyl)-1H-pyrazole-4-carboxamide (7b) provided excellent anticancer inhibition performance against the HepG2 cancer cell line with IC₅₀ values of 6.1 ± 1.9 and 7.9 ± 1.9 μM, respectively, compared to the standard reference drug, doxorubicin (IC₅₀ = 24.7 ± 3.2 μM). The two powerful anticancer compounds (7a and 7b) were further subjected to cell cycle analysis and apoptosis investigation in HepG2 using flow cytometry. We have also studied the enzymatic assay of these two compounds against some enzymes, namely, caspase-3, Bcl-2, Bax, and CDK-2. Interestingly, the molecular docking study revealed that compounds 7a and 7b could well embed in the active pocket of the CDK-2 enzyme via different interactions. Overall, the prepared pyrazole-indole hybrids (7a and 7b) can be proposed as strong anticancer candidate drugs against various cancer cell lines.

Berberine Exerts Anti-cancer Activity by Modulating Adenosine Monophosphate- Activated Protein Kinase (AMPK) and the Phosphatidylinositol 3-Kinase/ Protein Kinase B (PI3K/AKT) Signaling Pathways

Background

The antagonistic relationship between adenosine monophosphate-activated protein kinase (AMPK) and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling play a vital role in cancer development. The anti-cancer effects of berberine have been reported as a main component of the traditional Chinese medicine Rhizoma coptidis, although the roles of these signaling pathways in these effects have not been systematically reviewed.

METHODS

We searched the PubMed database for studies with keywords including ["berberine"] and ["tumor" or "cancer"] and ["AMPK"] or ["AKT"] published between January 2010 and July 2020, to elucidate the roles of the AMPK and PI3K/AKT pathways and their upstream and downstream targets in the anti-cancer effects of berberine.

RESULTS

The anti-cancer effects of berberine include inhibition of cancer cell proliferation, promotion of apoptosis and autophagy in cancer cells, and prevention of metastasis and angiogenesis. The mechanism of these effects involves multiple cell kinases and signaling pathways, including activation of AMPK and forkhead box transcription factor O3a (FOXO3a), accumulation of reactive oxygen species (ROS), and inhibition of the activity of PI3K/AKT, rapamycin (mTOR) and nuclear factor-κB (NF-κB). Most of these mechanisms converge on regulation of the balance of AMPK and PI3K/AKT signaling by berberine.

CONCLUSION

This evidence supports the possibility that berberine is a promising anti-cancer natural product, with pharmaceutical potential in inhibiting cancer growth, metastasis and angiogenesis via multiple pathways, particularly by regulating the balance of AMPK and PI3K/AKT signaling. However, systematic preclinical studies are still required to provide scientific evidence for further clinical studies.

Isorhamnetin inhibited the proliferation and metastasis of androgen-independent prostate cancer cells by targeting the mitochondrion-dependent intrinsic apoptotic and PI3K/Akt/mTOR pathway

The present study investigated the effects of Isorhamnetin on two types of prostate cancer cells (androgen-independent and androgen-dependent) and explored its possible mechanisms underlying such effects. Treatment with Isorhamnetin significantly inhibited cell growth and induced lactate dehydrogenase (LDH) release of androgen-independent DU145 and PC3 prostate cancer cells, but exhibited almost no toxicity effect on androgen-dependent LNCaP prostate cancer cell line or normal human prostate epithelial PrEC cells, which was achieved by the induction of apoptosis in a mitochondrion-dependent intrinsic apoptotic pathway. Furthermore, Isorhamnetin inhibited cell migration and invasion in concentration-dependent manners by enhancing mesenchymal−epithelial transition (MET) and inhibiting matrix metalloproteinase (MMP) 2 (MMP-2) and MMP-9 overexpression. In addition, Isorhamnetin also down-regulated the expression of phosphorylated PI3K (p-P13K), Akt (p-Akt), and mTOR (p-mTOR) proteins in both cancer cells, revealing Isorhamnetin to be a selective PI3K–Akt–mTOR pathway inhibitor. In summary, these findings propose that Isorhamnetin might be a novel therapeutic candidate for the treatment of androgen-independent prostate cancer.

Investigation of Olea ferruginea Roylebark extracts for potential in vitroantidiabetic and anticancer effects

This study was conducted to investigate the physicochemical, phytochemical, in vitro antidiabetic and anticancer potential of Olea ferruginea R bark. After extraction using Soxhlet, in vitro antidiabetic and cytotoxic activity on human hepatocellular carcinoma (HepG2) cells was assessed by nonenzymatic glycosylation of hemoglobin assay, alpha-amylase inhibition assay, glucose uptake by yeast cells, and 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide assay, respectively, and gene expression via real-time polymerase chain reaction. Primary and secondary metabolites were present in the extractants; polyphenols (35.61 ± 0.03) and flavonoids (64.33 ± 0.35 ) in the chloroform; and polysaccharides in the ethanol (268.75 ± 0.34), and glycosaponins (78.01 ± 0.07) in the methanol. The chloroform extract exhibited maximum antidiabetic potential, showing inhibition of nonenzymatic glycosylation of hemoglobin (65%), and alpha-amylase inhibition (32%) with maximum percent glucose uptake by the ethanol extract (78%). Only the ethanol extract had dose-dependent cytotoxic potential against the HepG2 cells. After 24-h exposure to the ethanol-extract, the expression of protein kinase B (Akt) remained unchanged, while the expression of B-cell lymphoma 2 (BCL2) and BCL2 associated X (BAX) changed significantly. After 48-h exposure, the expression of Akt decreased significantly, while that of BCL2 and BAX increased significantly. Olea ferruginea R bark possessed in vitro antidiabetic potential and anticancer/cytotoxic effects, attributable to the decline in the prosurvival signals of the Akt signaling pathway.

Using NMR Spectroscopy in the Fragment-Based Drug Discovery of Small-Molecule Anticancer Targeted Therapies

Against the challenge of providing personalized cancer care, the development of targeted therapies stands as a promising approach. The discovery of these agents can benefit from fragment-based drug discovery (FBDD) methods that help guide ligand design and provide key structural information on the targets of interest. In particular, nuclear magnetic resonance spectroscopy is a promising biophysical tool in fragment discovery due to its detection capabilities and versatility. This review provides an overview of FBDD, describes the basis of NMR-based fragment screening, summarizes some exciting technical advances reported over the past decades, and closes with a discussion of selected case studies where this technique has been used as part of drug discovery campaigns to produce lead compounds towards the design of anti-cancer targeted therapies.

Cardamonin induces G2/M phase arrest and apoptosis through inhibition of NF-κB and mTOR pathways in ovarian cancer

Cardamonin, a natural chalcone, is reported to induce apoptosis and inhibit cancer cell growth. However, the mechanisms underlying the therapeutic effects of cardamonin remain to be established. Here, we have focused on cardamonin-induced apoptosis in ovarian cancer cells, both in vitro and in vivo. The effects of cardamonin on cell cycle patterns and apoptotic responses of cells were assessed in this study. Western blot was employed to determine the effects of cardamonin on expression of cell cycle- and apoptosis-related proteins. Our results indicate that cardamonin suppresses cancer cell growth by inducing G2/M phase arrest and apoptosis through targeted inhibition of NF-κB and mTOR pathways. The collective findings provide novel insights into the pathways responsible for the anticancer effects of cardamonin and support its potential utility as a clinical therapeutic agent for ovarian cancer.

Molecular targeted therapy: novel therapeutic approach for head and neck cancer

Cancer is a major public health burden worldwide, affecting millions of people each year. One of the major hallmarks of cancer is rapid growth and progression by evasion of host immune responses. Tumor resistance to conventional anticancer drugs by several mechanisms, such as drug inactivation, efflux pumps and enhanced toxicity to normal cells decreases their clinical efficacy. These limitations resulted in the development of new targeted agents, such as monoclonal antibodies and small molecule inhibitors that have high tumor specificity. This paper discusses the therapeutic applications of novel molecular targeted agents and immunotherapy as an alternative treatment option for head and neck cancers, as well as provides insight into future therapeutic approaches for advanced head and neck cancers.

Mitochondria membrane transformations in colon and prostate cancer and their biological implications

Mitochondria have emerged as important determinants in cancer progression and malignancy. However, the role of mitochondrial membranes in cancer onset and progression has not been thoroughly investigated. This study compares the structural and functional properties of mitochondrial membranes in prostate and colon cancer cells in comparison to normal mitochondria, and possible therapeutic implications of these membrane changes. Specifically, isolation of cell mitochondria and preparation of inverted sub-mitochondrial particles (SMPs) illuminated significant cancer-induced modulations of membrane lipid compositions, fluidity, and activity of cytochrome c oxidase, one of the key mitochondrial enzymes. The experimental data further show that cancer-associated membrane transformations may account for mitochondria targeting by betulinic acid and resveratrol, known anti-cancer molecules. Overall, this study probes the relationship between cancer and mitochondrial membrane transformations, underlying a potential therapeutic significance for mitochondrial membrane targeting in cancer.

NF-κB pathway took part in the development of apoptosis mediated by miR-15a and oxidative stress via mitochondrial pathway in ammonia-treated chicken splenic lymphocytes

Ammonia, a kind of gas with pungent smell, is harmful to livestock and people, and has bad influence on the atmosphere. However, the mechanism of splenic toxicity caused by ammonia is still poorly understood. The aim of present study was to investigate the effect of ammonia on chicken splenic lymphocytes from the perspective of apoptosis. Chicken splenic lymphocytes were divided into the control group and the two ammonium treatment groups (1 mmol/L and 5 mmol/L ammonia), and were cultured for 24 h. CCK-8, flow cytometry (FC), fluorescence microscope, quantitative real-time PCR (qRT-PCR), and Western blot were used to study the differences between different groups. The results showed that ammonia exposure increased the release of calcium (Ca)²⁺ and reactive oxygen species (ROS) from mitochondrion. Besides, we found an increase in mRNA levels of glutathione peroxidase (GPx), inflammation-related genes (nuclear factor-κB (NF-κB), cyclooxygenase-2 (COX-2), inducible nitric (iNOS), tumor necrosis factor-α (TNF-α), and transforming growth factor-β (TGF-β)), apoptosis-related genes (B-cell lymphoma-2 (BCL-2), Bcl-2 associated X protein (BAX), Cytochrome c (Cytc), apoptotic protease activating factor 1 (APAF1), Caspase-9, and Caspase-3), and an increase in protein levels of NF-κB, iNOS, BAX, Cytc, Caspase-9, and Caspase-3. At the same time, we found a decrease level of GPx protein expression, and a decrease level of glutathione S-transferase (GST) mRNA expression, and a decrease level of heme oxygenase-1 (HO-1) and BCL-2 mRNA and protein expression in splenic lymphocytes exposed to ammonia. Meanwhile, miR-15a expression increased under ammonia exposure. In summary, these results indicated that ammonia induced oxidative stress, promoted the release of Ca²⁺, Cytc, and ROS from mitochondria, and then induced mitochondria-mediated inflammatory response, finally triggered apoptosis in chicken splenic lymphocytes.

Copper (II) Metallodendrimers Combined with Pro-Apoptotic siRNAs as a Promising Strategy Against Breast Cancer Cells

Cancer treatment with small interfering RNA (siRNA) is one of the most promising new strategies; however, transfection systems that increase its bioavailability and ensure its delivery to the target cell are necessary. Transfection systems may be just vehicular or could contain fragments with anticancer activity that achieves a synergistic effect with siRNA. Cationic carbosilane dendrimers have proved to be powerful tools as non-viral vectors for siRNA in cancer treatment, and their activity might be potentiated by the inclusion of metallic complexes in its dendritic structure. We have herein explored the interaction between Schiff-base carbosilane copper (II) metallodendrimers, and pro-apoptotic siRNAs. The nanocomplexes formed by metallodendrimers and different siRNA have been examined for their zeta potential and size, and by transmission electron microscopy, fluorescence polarisation, circular dichroism, and electrophoresis. The internalisation of dendriplexes has been estimated by flow cytometry and confocal microscopy in a human breast cancer cell line (MCF-7), following the ability of these metallodendrimers to deliver the siRNA into the cell. Finally, in vitro cell viability experiments have indicated effective interactions between Cu (II) dendrimers and pro-apoptotic siRNAs: Mcl-1 and Bcl-2 in breast cancer cells. Combination of the first-generation derivatives with chloride counterions and with siRNA increases the anticancer activity of the dendriplex constructs and makes them a promising non-viral vector.

Molecular docking analysis of Bcl-2 with phyto-compounds

The Bcl-2 protein is liked in several cancers and drug resistance to therapy is also known in this context. There are many Bcl-2 inhibitors under clinical trials. It is of further interest to design new Bcl2 inhibitors from phyto compounds such as artesunate, bruceantin, maytansin, Salvicine, indicine N-oxide, kamebanin and oxyacanthine. We report the optimal binding features of these compounds with Bcl-2 for further consideration towards in vitro and in vivo validation.

A small-molecule ARTS mimetic promotes apoptosis through degradation of both XIAP and Bcl-2

Many human cancers over-express B cell lymphoma 2 (Bcl-2) or X-linked inhibitor of apoptosis (IAP) proteins to evade cell death. The pro-apoptotic ARTS (Sept4_i2) protein binds directly to both Bcl-2 and XIAP and promotes apoptosis by stimulating their degradation via the ubiquitin-proteasome system (UPS). Here we describe a small molecule, A4, that mimics the function of ARTS. Microscale thermophoresis assays showed that A4 binds XIAP, but not cellular inhibitor of apoptosis protein 1 (cIAP1). A4 binds to a distinct ARTS binding pocket in the XIAP-BIR3 (baculoviral IAP repeat 3) domain. Like ARTS, A4 stimulated poly-ubiquitylation and UPS-mediated degradation of XIAP and Bcl-2, but not cIAP1, resulting in caspase-9 and -3 activation and apoptosis. In addition, over-expression of XIAP rescued HeLa cells from A4-induced apoptosis, consistent with the idea that A4 kills by antagonizing XIAP. On the other hand, treatment with the SMAC-mimetic Birinapant induced secretion of tumour necrosis factor-α (TNFα) and killed ~50% of SKOV-3 cells, and addition of A4 to Birinapant-treated cells significantly reduced secretion of TNFα and blocked Birinapant-induced apoptosis. This suggests that A4 acts by specifically targeting XIAP. The effect of A4 was selective as peripheral blood mononuclear cells and normal human breast epithelial cells were unaffected. Furthermore, proteome analysis revealed that cancer cell lines with high levels of XIAP were particularly sensitive to the killing effect of A4. These results provide proof of concept that the ARTS binding site in XIAP is "druggable". A4 represents a novel class of dual-targeting compounds stimulating apoptosis by UPS-mediated degradation of important anti-apoptotic oncogenes.

Prolonged Persistence of Chimeric Antigen Receptor (CAR) T Cell in Adoptive Cancer Immunotherapy: Challenges and Ways Forward

CAR T cell qualities, such as persistence and functionality play important roles in determining the outcome of cancer immunotherapy. In spite of full functionality, it has been shown that poor persistence of CAR T cells can limit an effective antitumor immune response. Here, we outline specific strategies that can be employed to overcome intrinsic and extrinsic barriers to CAR T cell persistence. We also offer our viewpoint on how growing use of CAR T cells in various cancers may require modifications in the intrinsic and extrinsic survival signals of CAR T cells. We anticipate these amendments will additionally provide the rationales for generation of more persistent, and thereby, more effective CAR T cell treatments. CAR T cell qualities, such as persistence and functionality play important roles in determining the outcome of cancer immunotherapy. In spite of full functionality, it has been shown that poor persistence of CAR T cells can limit an effective antitumor immune response. Here, we outline specific strategies that can be employed to overcome intrinsic and extrinsic barriers to CAR T cell persistence. We also offer our viewpoint on how growing use of CAR T cells in various cancers may require modifications in the intrinsic and extrinsic survival signals of CAR T cells. We anticipate these amendments will additionally provide the rationales for generation of more persistent, and thereby, more effective CAR T cell treatments.

Spatial targeting of Bcl-2 on endoplasmic reticulum and mitochondria in cancer cells by lipid nanoparticles

The presence of the same proteins at different sub-cellular locations with completely different functions adds to the complexity of signalling pathways in cancer.

miR-636 represses cell survival by targeting CDK6/Bcl-2 in cervical cancer

Cervical cancer is widely known as one of the most common types of cancer diagnosed in women, and microRNAs (miRNAs) has been characterized as an important regulator in tumor progression, such as cervical cancer. MiR-636 was found to play a tumor suppressor role in hepatocellular carcinoma tumorigenesis. However, the tumorigenic mechanism of miR-636 on cervical cancer has not yet been found. In the present study, we first found that miR-636 was significantly downregulated in cervical cancer tissues and cell lines. in vitro gain- and loss-of-function assays revealed that overexpression of miR-636 inhibited cell proliferation and induced cell apoptosis, while knockdown of miR-636 reversed the effect on cervical tumorigenesis. Furthermore, cyclin-dependent kinase 6 (CDK6) and B-cell lymphoma 2 (Bcl-2) were characterized as targets of miR-636. Notably, overexpression of CDK6 or Bcl-2 could reverse the inhibitory effect of miR-636 on cervical cancer progression. Mechanistically, miR-636 repressed cell survival by targeting CDK6/Bcl-2 in cervical cancer, which may be the underlying mechanism of miR-636-inhibited cervical progression. In conclusion, our findings clarified the biologic significance of miR-636/CDK6/Bcl-2 axis in cervical cancer progression and suggested the potential therapeutic target ability of miR-636 in treatment of cervical cancer.

Streptomyces sp. MUM256: A Source for Apoptosis Inducing and Cell Cycle-Arresting Bioactive Compounds against Colon Cancer Cells

New and effective anticancer compounds are much needed as the incidence of cancer continues to rise. Microorganisms from a variety of environments are promising sources of new drugs; Streptomyces sp. MUM256, which was isolated from mangrove soil in Malaysia as part of our ongoing efforts to study mangrove resources, was shown to produce bioactive metabolites with chemopreventive potential. This present study is a continuation of our previous efforts and aimed to investigate the underlying mechanisms of the ethyl acetate fraction of MUM256 crude extract (MUM256 EA) in inhibiting the proliferation of HCT116 cells. Our data showed that MUM256 EA reduced proliferation of HCT116 cells via induction of cell-cycle arrest. Molecular studies revealed that MUM256 EA regulated the expression level of several important cell-cycle regulatory proteins. The results also demonstrated that MUM256 EA induced apoptosis in HCT116 cells mediated through the intrinsic pathway. Gas chromatography-mass spectrometry (GC-MS) analysis detected several chemical compounds present in MUM256 EA, including cyclic dipeptides which previous literature has reported to demonstrate various pharmacological properties. The cyclic dipeptides were further shown to inhibit HCT116 cells while exerting little to no toxicity on normal colon cells in this study. Taken together, the findings of this project highlight the important role of exploring the mangrove microorganisms as a bioresource which hold tremendous promise for the development of chemopreventive drugs against colorectal cancer.

Destined to Die: Apoptosis and Pediatric Cancers

Apoptosis (programmed cell death) is a systematic and coordinated cellular process that occurs in physiological and pathophysiological conditions. Sidestepping or resisting apoptosis is a distinct characteristic of human cancers including childhood malignancies. This review dissects the apoptosis pathways implicated in pediatric tumors. Understanding these pathways not only unraveled key molecules that may serve as potential targets for drug discovery, but also molecular nodes that integrate with other signaling networks involved in processes such as development. This review presents current knowledge of the complex regulatory system that governs apoptosis with respect to other processes in pediatric cancers, so that fresh insights may be derived regarding treatment resistance or for more effective treatment options.

Conventional-Vincristine Sulfate vs. Modified Protocol of Vincristine Sulfate and L-Asparaginase in Canine Transmissible Venereal Tumor

Background: Vincristine (VCR) is a mono-chemotherapy for canine transmissible venereal tumor (CTVT). L-asparaginase (LAP) is usually used in combination with other drugs. Previously, LAP-VCR protocol was applied for the CTVT-VCR-resistant cases. However, there were a few reports about using this protocol since the first visit.

Aims: To firstly investigate the effectiveness of combining chemotherapy (Vincristine and L-asparaginase, VCR-LAP) in normal CTVT case. Secondly, to compare this protocol with the conventional (Vincristine, VCR) protocol before and during treatment in 24 CTVT dogs.

Materials and Methods: Clinical signs, tumor relative volume, and histopathological change [amount of CTVT cells, tumor-infiltrating lymphocytes (TILs), TILs/CTVT ratio, collagen area, and Ki-67 proliferative index (PI)] were the treatment evaluation parameters. Moreover, transcriptome analysis of apoptotic (Bcl-2, Bax), drug-resistant genes (ABCB1, ABCG2), and BCL-2 and BAX expression were also included.

Results: Both protocols gave the decreased tumor volume, increased TILs/CTVT ratios and collagen area in the mass. Interestingly, the combination protocol decreased treatment time. There were two resistant cases after treatment with VCR. The expression of Bcl-2 and Bax were decreased, and this may indicate the better response after treatment. Moreover, both drug resistant genes did not increase after treatment.

Conclusion: The main finding of this study is that the combination protocol did not only decrease treatment duration time but also gave the effectiveness of treatment outcomes in CTVT cases. Therefore, the application of the new protocol could be used by the field practitioners.

Molecular docking studies of bioactive compounds from Annona muricata Linn as potential inhibitors for Bcl-2, Bcl-w and Mcl-1 antiapoptotic proteins

Annona muricata Linn or usually identified as soursop is a potential anticancer plant that has been widely reported to contain valuable chemopreventive agents known as annonaceous acetogenins. The antiproliferative and anticancer activities of this tropical and subtropical plant have been demonstrated in cell culture and animal studies. A. muricata L. exerts inhibition against numerous types of cancer cells, involving multiple mechanism of actions such as apoptosis, a programmed cell death that are mainly regulated by Bcl-2 family of proteins. Nonetheless, the binding mode and the molecular interactions of the plant's bioactive constituents have not yet been unveiled for most of these mechanisms. In the current study, we aim to elucidate the binding interaction of ten bioactive phytochemicals of A. muricata L. to three Bcl-2 family of antiapoptotic proteins viz. Bcl-2, Bcl-w and Mcl-1 using an in silico molecular docking analysis software, Autodock 4.2. The stability of the complex with highest affinity was evaluated using MD simulation. We compared the docking analysis of these substances with pre-clinical Bcl-2 inhibitor namely obatoclax. The study identified the potential chemopreventive agent among the bioactive compounds. We also characterized the important interacting residues of protein targets which involve in the binding interaction. Results displayed that anonaine, a benzylisoquinoline alkaloid, showed a high affinity towards the Bcl-2, thus indicating that this compound is a potent inhibitor of the Bcl-2 antiapoptotic family of proteins.

Mitochondria in cancer: in the aspects of tumorigenesis and targeted therapy

Mitochondria play pivotal roles in most eukaryotic cells, ranging from energy production to regulation of apoptosis. As sites of cellular respiration, mitochondria experience accumulation of reactive oxygen species (ROS) due to damage in electron transport chain carriers. Mutations in mitochondrial DNA (mtDNA) as well as nuclear DNA are reported in various cancers. Mitochondria have a dual role in cancer: the development of tumors due to mutations in mitochondrial genome and the generation of ROS. Impairment in the mitochondria-regulated apoptosis pathway accelerates tumorigenesis. Numerous strategies targeting mitochondria have been developed to induce the mitochondrial (i.e. intrinsic) apoptosis pathway in cancer cells. This review elaborates the roles of mitochondria in cancer with respect to mutations and apoptosis and discusses mitochondria-targeting strategies as cancer therapies to enhance the killing of cancer cells.

Overcoming drug-resistance in lung cancer cells by paclitaxel loaded galactoxyloglucan nanoparticles

Paclitaxel, an effective chemotherapeutic drug, is insoluble in aqueous solvents and is usually administered with excipients which have side effects. The use of this drug is also limited due to multi-drug resistance. In this study polysaccharide nanoparticles are used in the delivery of chemotherapeutic drug while minimizing side-effects, solubility issues and drug resistance. The use of biopolymers like galactoxyloglucan to synthesize nanoparticle makes it more biocompatible. This study involves the synthesis of PST-PTX nanoparticles using tamarind seed polysaccharide and Paclitaxel by epichlorohydrin crosslinking. The particles were further characterized by Dynamic Light Scattering (DLS), High-resolution transmission electron microscopy (HR-TEM) Fourier Transform Infrared Spectroscopy (FTIR) and UV-Visible spectroscopy. The cytotoxicity of PST-PTX nanoparticles in cancer cell lines and resistant cancer cell lines were determined by MTT assay. The quantitative analysis of cell death was determined by Annexin V dead cell assay, Caspase 3/7 assay and expression of pro-apoptotic protein Bax. The ability of the nanoparticle to overcome multi-drug resistance was evaluated by the expression of multidrug-resistant proteins P-glycoprotein (P-gp) and Breast cancer resistant protein (BCRP) in lung adenocarcinoma resistant cells (A549^R). The present study provides evidence for the ability of PST-PTX nanoparticle to overcome multi-drug resistance and cause apoptotic cell death. The particle was found to be more effective than Paclitaxel in causing cell death in resistant cancer cells. Moreover, the particles were found to downregulate the expression of multi-drug resistant proteins P-gp and BCRP in resistant cell lines suggesting the ability of PST-PTX nanoparticles to overcome multi-drug resistance.

Oncogenic Signaling in Tumorigenesis and Applications of siRNA Nanotherapeutics in Breast Cancer

Overexpression of oncogenes and cross-talks of the oncoproteins-regulated signaling cascades with other intracellular pathways in breast cancer could lead to massive abnormal signaling with the consequence of tumorigenesis. The ability to identify the genes having vital roles in cancer development would give a promising therapeutics strategy in combating the disease. Genetic manipulations through siRNAs targeting the complementary sequence of the oncogenic mRNA in breast cancer is one of the promising approaches that can be harnessed to develop more efficient treatments for breast cancer. In this review, we highlighted the effects of major signaling pathways stimulated by oncogene products on breast tumorigenesis and discussed the potential therapeutic strategies for targeted delivery of siRNAs with nanoparticles in suppressing the stimulated signaling pathways.

Identification of a Novel Bcl-2 Inhibitor by Ligand-Based Screening and Investigation of Its Anti-cancer Effect on Human Breast Cancer Cells

Bcl-2 family protein is an important factor in regulating apoptosis and is associated with cancer. The anti-apoptotic proteins of Bcl-2 family, such as Bcl-2, are overexpression in numerous tumors, and contribute to cancer formation, development, and therapy resistance. Therefore, Bcl-2 is a promising target for drug development, and several Bcl-2 inhibitors are currently undergoing clinical trials. In this study, we carried out a QSAR-based virtual screening approach to develop potential Bcl-2 inhibitors from the SPECS database. Surface plasmon resonance (SPR) binding assay was performed to examine the interaction between Bcl-2 protein and the screened inhibitors. After that, we measured the anti-tumor activities of the 8 candidate compounds, and found that compound M1 has significant cytotoxic effect on breast cancer cells. We further proved that compound M1 downregulated Bcl-2 expression and activated apoptosis by inducing mitochondrial dysfunction. In conclusion, we identified a novel Bcl-2 inhibitor by QSAR screening, which exerted significant cytotoxic activity in breast cancer cells through inducing mitochondria-mediated apoptosis.

Combination Treatment with the BRAFV600E Inhibitor Vemurafenib and the BH3 Mimetic Navitoclax for BRAF-Mutant Thyroid Carcinoma

BACKGROUND

Vemurafenib is a selective BRAF inhibitor (BRAFi) that has shown promising activity in BRAF^V600E-positive papillary thyroid cancer (PTC). However, adverse events and resistance to a single-agent BRAFi often require discontinuation of the targeted therapy in BRAF^V600E-positive PTC. Thus, this study investigated the expression of anti-apoptotic B-cell lymphoma 2 (BCL-2) family members, which are frequently overexpressed in many human cancers to inhibit apoptosis, in PTC harboring the BRAF^V600E mutation after BRAFi treatment, and then evaluated the cytotoxic effects of a homology 3 domain (BH3)-mimetic in combination with a BRAFi.

METHODS

K1 cells (BRAF^V600E-positive human PTC) were treated with various concentrations of vemurafenib to investigate the effect of the BRAFi. In addition, the study analyzed the protein expression profiles of phosphorylated ERK1/2 (p-ERK 1/2) and anti-apoptotic BCL-2 family after vemurafenib treatment and selected the target anti-apoptotic protein. Antitumor effects were measured by cell counting, and effects on apoptosis were determined by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay and Western blot analysis.

RESULTS

At a concentration of 10 μM, vemurafenib inhibited the growth of K1 cells by 49.4%. Western blot analysis following exposure to 10 μM vemurafenib revealed that p-ERK1/2 gradually decreased over 24 hours, but the expression of B-cell lymphoma-extralarge (BCL-XL) and BCL-2 increased after 12 hours of treatment. Based on this result, the K1 cells were treated with navitoclax (BCL-2/BCL-XL inhibitor) for 24 hours up to a concentration of 4 μM, which resulted in negligible effects on cell survival. However, a combination treatment of 0.5 μM navitoclax with 1 μM vemurafenib resulted in significantly enhanced cell growth inhibition and increased apoptosis.

CONCLUSIONS

The results of the present study show that vemurafenib increased the expression of anti-apoptotic proteins of the BCL-2 family. Thus, the combination of vemurafenib with navitoclax may be effective in BRAF^V600E-positive PTC treatment.

A critical regulator of Bcl2 revealed by systematic transcript discovery of lncRNAs associated with T-cell differentiation

Normal T-cell differentiation requires a complex regulatory network which supports a series of maturation steps, including lineage commitment, T-cell receptor (TCR) gene rearrangement, and thymic positive and negative selection. However, the underlying molecular mechanisms are difficult to assess due to limited T-cell models. Here we explore the use of the pro-T-cell line P5424 to study early T-cell differentiation. Stimulation of P5424 cells by the calcium ionophore ionomycin together with PMA resulted in gene regulation of T-cell differentiation and activation markers, partially mimicking the CD4^-CD8^- double negative (DN) to double positive (DP) transition and some aspects of subsequent T-cell maturation and activation. Global analysis of gene expression, along with kinetic experiments, revealed a significant association between the dynamic expression of coding genes and neighbor lncRNAs including many newly-discovered transcripts, thus suggesting potential co-regulation. CRISPR/Cas9-mediated genetic deletion of Robnr, an inducible lncRNA located downstream of the anti-apoptotic gene Bcl2, demonstrated a critical role of the Robnr locus in the induction of Bcl2. Thus, the pro-T-cell line P5424 is a powerful model system to characterize regulatory networks involved in early T-cell differentiation and maturation.

Bim escapes displacement by BH3-mimetic anti-cancer drugs by double-bolt locking both Bcl-XL and Bcl-2

Tumor initiation, progression and resistance to chemotherapy rely on cancer cells bypassing programmed cell death by apoptosis. We report that unlike other pro-apoptotic proteins, Bim contains two distinct binding sites for the anti-apoptotic proteins Bcl-XL and Bcl-2. These include the BH3 sequence shared with other pro-apoptotic proteins and an unexpected sequence located near the Bim carboxyl-terminus (residues 181-192). Using automated Fluorescence Lifetime Imaging Microscopy - Fluorescence Resonance Energy Transfer (FLIM-FRET) we show that the two binding interfaces enable Bim to double-bolt lock Bcl-XL and Bcl-2 in complexes resistant to displacement by BH3-mimetic drugs currently in use or being evaluated for cancer therapy. Quantifying in live cells the contributions of individual amino acids revealed that residue L185 previously thought involved in binding Bim to membranes, instead contributes to binding to anti-apoptotic proteins. This double-bolt lock mechanism has profound implications for the utility of BH3-mimetics as drugs. ​.

Structural characterization and in vitro antitumor activity of A polysaccharide from Artemisia annua L. (Huang Huahao)

One water-soluble polysaccharide (AAP), with a molecular weight of 6.3 × 104 Da, was isolated from Artemisia annua L. Structrual analysis indicated that AAP was found to be a 1, 3-α-linked and 1, 3, 6-α-linked Glcp backbone, with a branch of 1, 6-α-linked Glcp and terminal 1-linked-L-Rhap along the main chain in a ratio of 1: 1: 1: 1. MTT assay showed that AAP reduced the cell viability of HepG2 cells in a concentration-dependent manner. DAPI staining and Flow cytometric analysis revealed that AAP suppressed cells proliferation, not most at least via inducing p65-dependent mitochondrial signaling pathway, as evidenced by more activation of caspase-3 and -9, down-regulation of Bcl-2 protein, up-regulation of Bax protein and release of cytochrome c from mitochondria into cytosol, as well as suppression of the nuclear factor-κB (NF-κB) p65. These data confirmed AAP inhibits HepG2 cell growth via inducing caspase-dependent mitochondrial apoptosis and inhibition of NF-κB p65.

Sleep deprivation disrupts striatal anti-apoptotic responses in 6-hydroxy dopamine-lesioned parkinsonian rats

Objective(s):

The present study was conducted to examine the effect of sleep deprivation (SD) on the anti-apoptotic pathways in Parkinsonian rats.

Materials and Methods:

Male Wistar rats (n = 40) were assigned to four groups (10 animals each): sham surgery (Sham), 6-hydroxydopamine (6-OHDA)-lesioned (OH), 6-OHDA-lesioned plus grid control (OH+GC), 6-OHDA-lesioned plus SD (OH+SD). Parkinson’s disease (PD) model was induced by the unilateral intra-striatal infusion of 6-OHDA (10 µg/rat). SD (4 hr/day, for 14 days) was induced using a multiple platforms water tank. On the last day of interventions, animals were subjected to open field test for horizontal motor performance assessment. Also, brain-derived neurotrophic factor (BDNF), Bcl-2 and Bax were assessed in the striatum of study groups.

Results:

SD obscured the motor deficits of PD animals observed in open field test. BDNF level and Bcl2/Bax ratio significantly increased in the OH group, and SD reduced their levels in the PD animals.

Conclusion:

SD suppressed the anti-apoptotic compensatory responses in the striatum; therefore, it may accelerate continual neuronal cell death in PD.

Expression of P53, BAX, and BCL-2 in human malignant melanoma and squamous cell carcinoma cells after tea tree oil treatment in vitro

Tea tree oil (TTO) is an essential oil obtained by steam distillation from the leaves of Melaleuca alternifolia (Myrtaceae). This oil has traditionally been used for the treatment of various skin infections. The present study aimed to investigate the cytotoxic effects of TTO against two representative types of human skin cancer, namely malignant melanoma (A-375) and squamous cell carcinoma (HEp-2).To outline the basic molecular mechanism involved in apoptosis induction in A-375 and HEp-2 cell lines, Annexin V/PI staining for apoptosis detection, cell cycle analysis were monitored using flow cytometry and mRNA expression levels of the apoptosis-regulatory genes P53, BAX, and BCL-2 were determined by real-time PCR and western blot after treatment with TTO. Results showed that TTO exhibited a strong cytotoxicity towards A-375 and HEp-2 cell lines, with IC50 values of 0.038% (v/v) and 0.024% (v/v) respectively. This cytotoxicity resulted from TTO induced apoptosis in both A-375 and HEp-2 cell lines as evidenced by morphological features of apoptosis and Annexin V/PI staining results in addition to the activation of caspase-3/7 and -9, upregulation of pro-apoptotic genes (P53 and BAX) and downregulation of the anti-apoptotic gene BCL-2. Additionally, cell cycle analysis showed that TTO caused cell cycle arrest mainly at G2/M phase. Taken together, the results of this study reveal that TTO is an effective apoptosis inducer in A-375 and HEp-2 cancer cell lines, indicating that it could be a promising chemopreventive candidate to be used in topical formulations against melanoma and squamous cell cancers; however, further in vivo studies may be warranted.

Loss of p53 suppresses replication-stress-induced DNA breakage in G1/S checkpoint deficient cells

In cancer cells, loss of G1/S control is often accompanied by p53 pathway inactivation, the latter usually rationalized as a necessity for suppressing cell cycle arrest and apoptosis. However, we found an unanticipated effect of p53 loss in mouse and human G1-checkpoint-deficient cells: reduction of DNA damage. We show that abrogation of the G1/S-checkpoint allowed cells to enter S-phase under growth-restricting conditions at the expense of severe replication stress manifesting as decelerated DNA replication, reduced origin firing and accumulation of DNA double-strand breaks. In this system, loss of p53 allowed mitogen-independent proliferation, not by suppressing apoptosis, but rather by restoring origin firing and reducing DNA breakage. Loss of G1/S control also caused DNA damage and activation of p53 in an in vivo retinoblastoma model. Moreover, in a teratoma model, loss of p53 reduced DNA breakage. Thus, loss of p53 may promote growth of incipient cancer cells by reducing replication-stress-induced DNA damage.

siRNAs Targeting Growth Factor Receptor and Anti-Apoptotic Genes Synergistically Kill Breast Cancer Cells through Inhibition of MAPK and PI-3 Kinase Pathways

Breast cancer, the second leading cause of female deaths worldwide, is usually treated with cytotoxic drugs, accompanied by adverse side-effects, development of chemoresistance and relapse of disease condition. Survival and proliferation of the cancer cells are greatly empowered by over-expression or over-activation of growth factor receptors and anti-apoptotic factors. Identification of these key players that cross-talk to each other, and subsequently, knockdown with their respective siRNAs in a synchronous manner could be a promising approach to precisely treat the cancer. Since siRNAs demonstrate limited cell permeability and unfavorable pharmacokinetic behaviors, pH-sensitive nanoparticles of carbonate apatite were employed to efficiently carry the siRNAs in vitro and in vivo. By delivering selective siRNAs against the mRNA transcripts of the growth factor receptors, such as ER, ERBB2 (HER2), EGFR and IGFR, and anti-apoptotic protein, such as BCL2 in human (MCF-7 and MDA-MB-231) and murine (4T1) breast cancer cell lines, we found that ESR1 along with BCL-2, or with ERBB2 and EGFR critically contributes to the growth/survival of the cancer cells by activating the MAPK and PI-3 kinase pathways. Furthermore, intravenous delivery of the selected siRNAs aiming to suppress the expression of ER/BCL2 and ER/ERBB2/EGFR groups of proteins led to a significant retardation in tumor growth in a 4T1-induced syngeneic mouse model.

In Vivo Study of the Effects of ERβ on Apoptosis and Proliferation of Hormone-Independent Prostate Cancer Cell Lines PC-3M

OBJECTIVE

To evaluate the in vivo therapeutic effects of attenuated Salmonella carrying PCDNA3.1-ERβ plasmid in hormone-independent prostatic cancer in nude mice and to clarify the mechanism by which estrogen receptor β (ERβ) induces apoptosis and proliferation in prostatic cancer cells in mice.

METHODS

The orthotopic prostatic cancer models of mice were randomly divided as follows: MOCK group, treated with PBS, PQ group, treated with attenuated Salmonella alone, PQ-PCDNA3.1 group, treated with attenuated Salmonella carrying PCDNA3.1 plasmid, and PQ-PCDNA3.1-ERβ group, treated with the attenuated Salmonella carrying PCDNA3.1-ERβ plasmid. Then, 10 μl of the plasmid-containing solution, comprising 1 × 107 cfu of the bacteria, was administered via intranasal delivery to each group except the MOCK group. The experimental methods included flow cytometry and terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick end-labelling (TUNEL) assay, immunohistochemistry, and western blotting.

RESULTS

Compared with the MOCK, PQ, and PQ-PCDNA3.1 groups, the weights of tumors in the PQ-PCDNA3.1-ERβ group were significantly reduced. The results of flow cytometry and TUNEL assay revealed that the number of apoptotic cells in the PQ-PCDNA3.1-ERβ group significantly increased. Compared with PQ-PCDNA3.1 group, the protein expression levels of ERβ, Bad, p-caspase 9, p-caspase 3, and cleaved PARP in the PQ-PCDNA3.1-ERβ group were significantly increased, while the expression levels of Akt, p-Akt, and Bcl-xl were decreased (P < 0.05).

CONCLUSION

The attenuated Salmonella carrying PCDNA3.1-ERβ plasmid could inhibit the growth of orthotopic prostatic cancer in mice by increasing the expression of ERβ.

Galangin Induces Apoptosis in MCF-7 Human Breast Cancer Cells Through Mitochondrial Pathway and Phosphatidylinositol 3-Kinase/Akt Inhibition

AIMS

The study aimed to investigate the molecular mechanism of inhibition of proliferation and apoptosis induction by galangin against MCF-7 human breast cancer cells.

METHODS

Cell Counting Kit-8 assay was used to assess cell viability and flow cytometry was used to detect cell apoptosis. The expression level of apoptosis-related proteins (cleaved-caspase-9, cleaved-caspase-8, cleaved-caspase-3, Bad, cleaved-Bid, Bcl-2, Bax, p-phosphatidylinositol 3-kinase [PI3K], and p-Akt) and cell cycle-related proteins (cyclin D3, cyclin B1, cyclin-dependent kinases CDK1, CDK2, CDK4, p21, p27, p53) were evaluated by Western blotting.

RESULTS

Galangin increased the expression of Bax and decreased the expression of Bcl-2 in a concentration-dependent manner, inhibited cell viability, and induced apoptosis. Meanwhile, the expression of cleavage of caspase-9, caspase-8, caspase-3, Bid, and Bad increased significantly while the expression of p-PI3K and p-Akt proteins decreased. In addition, the protein levels of cyclin D3, cyclin B1, CDK1, CDK2, and CDK4 were downregulated while the expression levels of p21, p27, and p53 were upregulated significantly.

CONCLUSION

Galangin could suppress the viability of MCF-7 cells and induce cell apoptosis via the mitochondrial pathway and PI3K/Akt inhibition as well as cell cycle arrest.

PYGB siRNA inhibits the cell proliferation of human osteosarcoma cell lines

Osteosarcoma is the most common malignant bone carcinoma that primarily occurs between childhood to adolescence. It was suggested by recent research that the Brain type glycogen phosphorylase (PYGB) gene may serve an important role in various types of cancer. In the present study, the PYGB gene was knocked down in order to evaluate the cell viability, invasion and migration of the human osteosarcoma cell lines MG63 and HOS. The expression levels of PYGB in osteosarcoma and bone cyst tissue samples, as well as in the osteosarcoma cell lines were identified using reverse transcription-quantitative polymerase chain reaction and western blot assay. Subsequently, a Cell Counting kit 8 assay was employed to evaluate cell proliferation. Cell apoptosis rate and cell cycle distribution were measured by flow cytometry. In addition, cell invasion and migration were evaluated through a Transwell assay. The expression levels of the cell apoptosis and tumor metastasis associated proteins B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein, E-cadherin, Twist, matrix metalloproteinase (MMP)-9 and MMP2 were measured via western blotting. PYGB exhibited a higher expression level in the osteosarcoma tissue samples, particularly in the human osteosarcoma cell lines MG63 and HOS. Knockdown of PYGB resulted in a decline in cell proliferation, invasion and migration, which was coupled with induced cell apoptosis and cell cycle arrest in MG63 and HOS cells. Furthermore, alterations in the expression of apoptosis and metastasis associated proteins indicated that small interfering (si)PYGB may have regulated cell viability by targeting the Bcl/Caspase and cyclin dependent kinase (CDK)-1 signaling pathway. In conclusion, PYGB siRNA exerted an inhibitory effect on the cell viability of the human osteosarcoma cells MG63 and HOS by blocking the Caspase/Bcl and CDK1 signaling pathway, highlighting novel potential therapeutic methods for treating osteosarcoma.

Apigenin induces apoptosis by suppressing Bcl-xl and Mcl-1 simultaneously via signal transducer and activator of transcription 3 signaling in colon cancer

Apigenin is a natural flavonoid that exhibits anti-proliferative activity and induces apoptosis in various types of cancer, including colon cancer. The aim of the present study was to determine the mechanism underlying the apoptosis-inducing effect of apigenin in colon cancer. Apigenin reduced the proliferation of colon cancer cell lines, stimulated the cleavage of PARP and induced apoptosis in a dose-dependent manner. Apigenin treatment also suppressed the expression of the anti-apoptotic proteins Bcl-xL and Mcl-1. Small interfering RNA was used to knockdown Bcl-xL and Mcl-1 expression alone and in concert, and the proliferation and apoptosis of cancer cells were subsequently measured. The knockdown of Bcl-xL and Mcl-1 expression together markedly suppressed cell proliferation and induced apoptosis. Apigenin treatment also inhibited the phosphorylation of signal transducer and activator of transcription 3 (STAT3), which targets Bcl-xL and Mcl-1. The results of the current study therefore determined that apigenin induces the apoptosis of colon cancer cells by inhibiting the phosphorylation of STAT3 and consequently downregulates the anti-apoptotic proteins Bcl-xL and Mcl-1.

The isolation, structural characterization and anti-osteosarcoma activity of a water soluble polysaccharide from Agrimonia pilosa

A homogenous polysaccharide (APP), with a molecular weight of 120 kDa, was isolated from the dried aerial parts of Agrimonia pilosa. Gas chromatography (GC) and GC-MS analysis revealed that APP has a backbone of 1,3-linked Glcp and 1,3, 6-linked Glcp, and branched with 1-linked Glcp terminal along the main chain in a relative ratio of 2:1:1. We investigated the response of human osteosarcoma U-2 OS cells to APP treatment. MTT result showed that APP significantly inhibited cell viability in a concentration dependent manner via induction of apoptotic death in U-2 OS cells, as determined by annexin V/propidium iodide (PI) staining. Western blot analysis also indicated that APP CRA increased in Bax/Bcl-2 ratios by up-regulating Bax expression and triggered the release of cytochrome c from mitochondria into the cytoplasm. Moreover, APP supplement induced the activation of caspase-3, and -9, but not caspase-8 in U-2 OS cells. Likewise, APP administration significantly suppressed tumor growth in BALB/C nude mice bearing U-2 OS xenograft tumors. All these results indicate that APP-induced apoptosis is associated with the activation of a caspase-3-mediated mitochondrial pathway.

Lipid nanoparticle siRNA cocktails for the treatment of mantle cell lymphoma

Mantle cell lymphoma is an aggressive and incurable subtype of non‐Hodgkin B cell lymphoma. Patients typically present with advanced disease, and most patients succumb within a decade of diagnosis. There is a clear and urgent need for novel therapeutic approaches that will affect mantle cell lymphoma through a unique mechanism compared to current therapies. This study examined the use of RNA interference (RNAi) therapy to attack mantle cell lymphoma at the mRNA level, silencing genes associated with cancer cell proliferation. We identified a lipid nanoparticle formulated with the lipidoid 306O₁₃ that delivered siRNA to JeKo‐1 and MAVER‐1 mantle cell lymphoma cell lines. Three therapeutic gene targets were examined for their effect on lymphoma growth. These included Cyclin D1, which is a cell cycle regulator, as well as Bcl‐2 and Mcl‐1, which prevent apoptosis. Gene knockdown with siRNA doses as low at 10 nM increased lymphoma cell apoptosis without carrier‐mediated toxicity. Silencing of Cyclin D1 induced apoptosis despite a twofold “compensation” upregulation of Cyclin D2. Upon simultaneous silencing of all three genes, nearly 75% of JeKo‐1 cells were apoptosing 3 days post‐transfection. Furthermore, cells proliferated at only 15% of their pretreatment rate. These data suggest that lipid nanoparticles‐formulated, multiplexed siRNA “cocktails” may serve as a beneficial addition to the treatment regimens for mantle cell lymphoma and other aggressive cancers.

MiR-124 acts as a tumor suppressor by inhibiting the expression of sphingosine kinase 1 and its downstream signaling in head and neck squamous cell carcinoma

By analyzing the expression profile of microRNAs in head and neck squamous cell carcinomas (HNSCC), we found that the expression level of miR-124 was 4.59-fold lower in tumors than in normal tissues. To understand its functions, we generated a miR-124-expressing subline (JHU-22^miR124) and a mock vector-transfected subline (JHU-22^vec) by transfecting the mimic of miR-124 into JHU-22 cancer cells. Restored expression of miR-124 in JHU-22^miR124 cells led to reduced cell proliferation, delayed colony formation, and decreased tumor growth, indicating a tumor-suppressive effect of miR-124. Subsequent target search revealed that the 3′-UTR of SphK1 mRNA carries a complementary site for the seed region of miR-124. SphK1 was also detected to be overexpressed in HNSCC cell lines, but down-expressed in JHU-22^miR124 cells and tumor xenografts. These results suggest that SphK1 is a target of miR-124. To confirm this finding, we constructed a 3′-UTR-Luc-SphK1 vector and a binding site-mutated luciferase reporter vector. Co-transfection of 3′-UTR-Luc-SphK1 with miR-124 expression vector exhibited a 9-fold decrease in luciferase activity compared with mutated vector, suggesting that miR-124 inhibits SphK1 activity directly. Further studies on downstream signaling demonstrated accumulation of ceramide, increased expression of the pro-apoptotic Bax, BAD and PARP, decreased expression of the anti-apoptotic Bcl-2 and Bcl-xL, and enhanced expression of cytochrome c and caspase proteins in JHU-22^miR124 compared with JHU-22^vec cells and tumor xenografts. We conclude that miR-124 acts as a tumor suppressor in HNSCC by directly inhibiting SphK1 activity and its downstream signals.

In vivo selection with lentiviral expression of Bcl2T69A/S70A/S87A mutant in hematopoietic stem cell-transplanted mice

Current in vivo selections for hematopoietic stem cell (HSC)-based gene therapy are drug dependent and not without risk of cytotoxicity or tumorigenesis. We developed a new in vivo selection system with the non-phosphorylatable Bcl2 mutant Bcl2^{T69A/S70A/S87A} (Bcl2^AAA), which makes in vivo selection drug independent and without risk of cytotoxicity or tumorigenesis. We demonstrated in HSC-transplanted mice that Bcl2^AAA facilitated efficient in vivo selection in the absence of any exogenously applied drugs under both myeloablative and non-myeloablative conditioning. In mice transplanted with retrovirally transduced sca-1-positive bone marrow cells, the marked cell level increased from 26.38% of input transduced cells to 92.61 ± 0.95% of peripheral blood cells for myeloablative transplantation or to 37.82 ± 6.35% for non-myeloablative transplantation 6 months after transplantation. Bcl2^AAA did not induce tumorigenesis and does not influence hematopoiesis and the function of the reconstituted blood system. However, the high-level constitutive expression of Bcl2^AAA mediated by retroviral vector induced exhaustion of the marked cells after tertiary transplantation. Fortunately, low-level constitutive expression of Bcl2^AAA driven by an internal promoter in lentiviral vector could both maintain the marked cell level (24.13 ± 5.27%, 27.17 ± 5.51%, 24.33 ± 5.08%, and 22.07 ± 4.44% for primary, secondary, tertiary, and quaternary recipients) and avoid the exhaustion of the marked cells even in quaternary recipients. Importantly, the low-level constitutive expression of Bcl2^AAA did not induce tumorigenesis. Thus, the in vivo selection employing the low-level constitutive expression of Bcl2^AAA provides a general platform which is relevant for widespread applications of gene therapy.

Salicylate •Phenanthroline copper (II) complex induces apoptosis in triple-negative breast cancer cells

In this study, we investigated anti-tumor activity and associated molecular mechanism of action of Salicylate ●Phenanthroline Copper (II) Complex in triple-negative breast cancer. Salicylate ●Phenanthroline Copper (II) Complex inhibited the growth of four breast cancer cell lines (MCF-7, T47D, MDA-MB-231 and BT-20) and induced apoptosis in a concentration-dependent manner. The effect was more profound in MDA-MB-231 and BT-20 triple-negative breast cancer cell lines. Western blot showed that the expression of the apoptosis-related protein Bcl-2, Bcl-xl and survivin was significantly reduced in MDA-MB-231 after treatment with Salicylate ●Phenanthroline Copper (II) Complex. In vivo, Salicylate ●Phenanthroline Copper (II) Complex administration significantly attenuated tumor growth of MDA-MB-231 xenografts, and the expression levels of Bcl-2, Bcl-xL and survivin were reduced as measured by immunohistochemical staining. These data suggest that Salicylate ●Phenanthroline Copper (II) Complex is a promising novel therapeutic drug for triple-negative breast cancer and warrants further study.