Antitumor effect of berberine against primary effusion lymphoma via inhibition of NF-κB pathway

Blocking LTB4 signaling-mediated TAMs recruitment by Rhizoma Coptidis sensitizes lung cancer to immunotherapy

BACKGROUND

Immune checkpoint blockade (ICB) induces durable immune responses across a spectrum of advanced cancers and revolutionizes the oncology field. However, only a subset of patients achieves long-lasting clinical benefits. Tumor-associated macrophages (TAMs) usually secrete immunosuppressive cytokines and contribute to the failure of ICB therapy. Therefore, it is crucial to mechanically manipulate the abundance and function of TAMs in the tumor microenvironment (TME), which can offer a promising molecular basis to improve the clinical response efficacy of ICB in cancer patients.

PURPOSE

This study aims to investigate TAMs in the immunosuppressive microenvironment to identify new therapeutic targets, improve the ability to predict and guide responses to clinical immunotherapy, and develop new strategies for immunotherapy of lung tumors.

METHODS

Lewis lung carcinoma (LLC) xenograft-bearing mouse models were established to analyze the antitumor activity of Rhizoma Coptidis (RC) in vivo. A systems pharmacology strategy was used to predict the correlation between RC and M2 macrophages. The effect of RC on the abundance of M2 macrophages was analyzed by flow cytometry of murine samples. Western blot was performed to analyze the expression of Leukotriene A4 hydrolase (LTA4H) and LTB4 receptor 1 (BLT1) in harvested lung cancer tissues. The impact of blocking leukotriene B4 (LTB4) signaling by RC on the recruitment of M2 macrophages was assessed in vitro and in vivo. Transwell migration assays were conducted to clarify the inhibition of macrophage migration by blocking LTB4. Lta4h-/- mice were used to investigate the sensitivity of immunotherapy to lung cancer by blocking the LTB4 signaling.

RESULTS

Here, we report that RC, an herbal medicine from the family Ranunculaceae, suppresses the recruitment and immunosuppressive function of TAMs, which in turn sensitizes lung cancer to ICB therapy. Firstly, a systems pharmacology strategy was proposed to identify combinatorial drugs for ICB therapy with a systems biology perspective of drug-target-pathway-TME phenotype. We predicted and verified that RC significantly inhibits tumor growth and the infiltration of M2-TAMs into TME of LLC tumor-bearing mice. Then, RC inhibits the recruitment of macrophages to the tumor TME via blocking LTB4 signaling, and suppresses the expression of immunosuppressive factors (IL-10, TGF-β and VEGF). As a result, RC enables CD8+ T cells to retain their proliferative and infiltrative abilities within the TME. Ultimately, these events promote cytotoxic T-cell-mediated clearance of tumor cells, which is further enhanced by the addition of anti-PD-L1 therapy. Furthermore, we employed LTA4H deficient mice (Lta4h-/- mice) to evaluate the antitumor efficiency, the results showed that the efficacy of immunotherapy was enhanced due to the synergistic effect of LTB4 signaling blockage and ICB inhibition, leading to remarkable inhibition of tumor growth in a mouse model of lung adenocarcinoma.

CONCLUSIONS

Taken together, these findings suggest that RC enhances antitumor immunity, providing a rationale for combining RC with immunotherapies as a potential anti-cancer treatment strategy.

MKK4 Inhibitors-Recent Development Status and Therapeutic Potential

MKK4 (mitogen-activated protein kinase kinase 4; also referred to as MEK4) is a dual-specificity protein kinase that phosphorylates and regulates both JNK (c-Jun N-terminal kinase) and p38 MAPK (p38 mitogen-activated protein kinase) signaling pathways and therefore has a great impact on cell proliferation, differentiation and apoptosis. Overexpression of MKK4 has been associated with aggressive cancer types, including metastatic prostate and ovarian cancer and triple-negative breast cancer. In addition, MKK4 has been identified as a key regulator in liver regeneration. Therefore, MKK4 is a promising target both for cancer therapeutics and for the treatment of liver-associated diseases, offering an alternative to liver transplantation. The recent reports on new inhibitors, as well as the formation of a startup company investigating an inhibitor in clinical trials, show the importance and interest of MKK4 in drug discovery. In this review, we highlight the significance of MKK4 in cancer development and other diseases, as well as its unique role in liver regeneration. Furthermore, we present the most recent progress in MKK4 drug discovery and future challenges in the development of MKK4-targeting drugs.

Alkaloid from Alstonia yunnanensis diels root against gastrointestinal cancer: Acetoxytabernosine inhibits apoptosis in hepatocellular carcinoma cells

Liver cancer belongs to Gastrointestinal (GI) malignancies which is a common clinical disease, a thorny public health problem, and one of the major diseases that endanger human health. Molecules from natural products (NPs) or their derivatives play an increasingly important role in various chronic diseases such as GI cancers. The chemical composition of the Alstonia yunnanensis Diels roots was studied using silica column chromatography, gel chromatography, recrystallization, and HPLC, and the compounds were structurally identified by modern spectral analysis using mass spectrometry (MS) and nuclear magnetic resonance (¹H-, ¹³C-, HMQC-, HMBC-, and ¹H-¹HCOSY-NMR), ultraviolet and visible spectrum (UV), and electronic Circular Dichroism (ECD). Acetoxytabernosine (AC), an indole alkaloid with antitumor activity, was isolated from Alstonia yunnanensis Diels root. The current study aimed to investigate the influence of AC on the cell proliferation of BEL-7402 and SMMC7721 and to elucidate the underlying mechanism. The absolute configuration of AC was calculated by ECD (electronic circular dichroism). The effects of AC on the viability of different tumor cell lines were studied by the SRB method. The death mode of human hepatoma cells caused by AC was studied by TUNEL cell apoptosis detection and AnnexinV-FITC/PI double staining image. Mitochondrial membrane potential was detected by JC-1. The effects of AC on the expression of apoptosis-related proteins (Caspase9, Caspase3, and Parp-1) in SMMC7721 and BEL-7402 cells were detected by western blot. It was found that the absolute configuration of AC is 19(s), 20(s)-Acetoxytabernosine. AC could induce apoptosis of SMMC7721 and BEL-7402, and block the replication of DNA in the G1 phase. Under the treatment of AC, the total protein expression of apoptosis-related proteins (Caspase9, Caspase3, and Parp-1) significantly decreased in SMMC7721 and BEL-7402. The results suggested that AC induced apoptosis through a caspase-dependent intrinsic pathway in SMMC7721 and BEL-7402, and natural product-based drug development is an important direction in antitumor drug discovery and research.

Berberine: An Important Emphasis on Its Anticancer Effects through Modulation of Various Cell Signaling Pathways

Cancer is the most commonly diagnosed type of disease and a major cause of death worldwide. Despite advancement in various treatment modules, there has been little improvement in survival rates and side effects associated with this disease. Medicinal plants or their bioactive compounds have been extensively studied for their anticancer potential. Novel drugs based on natural products are urgently needed to manage cancer through attenuation of different cell signaling pathways. In this regard, berberine is a bioactive alkaloid that is found in variety of plants, and an inverse association has been revealed between its consumption and cancer. Berberine exhibits an anticancer role through scavenging free radicals, induction of apoptosis, cell cycle arrest, inhibition of angiogenesis, inflammation, PI3K/AKT/mammalian target of rapamycin (mTOR), Wnt/β-catenin, and the MAPK/ERK signaling pathway. In addition, synergistic effects of berberine with anticancer drugs or natural compounds have been proven in several cancers. This review outlines the anticancer effects and mechanisms of action of berberine in different cancers through modulation of various cell signaling pathways. Moreover, the recent developments in the drug delivery systems and synergistic effect of berberine are explained.

Antitumor effect of acanthoic acid against primary effusion lymphoma via inhibition of c-FLIP

Acanthoic acid (AA) is an active substance that is extracted from Croton oblongifolius Roxb., a traditional plant in Thailand. The antiinflammatory effect of AA on NF-κB pathway has been exclusively reported, however, its anticancer effect is still lacking. PEL is a B cell lymphoma that is mostly found in HIV patients. The prognosis and progression of PEL patients are terribly poor with a median survival time less than 6 months, so the new effective treatment is urgently needed. In this study, we found that AA effectively inhibited PEL cell proliferation with IC50s at 120-130 μM in well-representative cells, while the IC50s of AA in PBMC were higher (>200 μM). AA increased percentages of Annexin V/PI positive cells, whereas adding of caspase inhibitor (Q-VD-OPh) prevented AA-induced cell death. The antiapoptotic protein, c-FLIP, was downregulated by AA which leading to the activation of caspase-8 and -3. Combination of AA and TRAIL dramatically enhanced apoptotic cell death. In PEL xenograft model, AA at the dose of 250 mg/kg effectively inhibited PEL tumor growth without detectable toxicities assessed by mice weight and appearance.

Berberine in Human Oncogenic Herpesvirus Infections and Their Linked Cancers

Human herpesviruses are known to induce a broad spectrum of diseases, ranging from common cold sores to cancer, and infections with some types of these viruses, known as human oncogenic herpesviruses (HOHVs), can cause cancer. Challenges with viral latency, recurrent infections, and drug resistance have generated the need for finding new drugs with the ability to overcome these barriers. Berberine (BBR), a naturally occurring alkaloid, is known for its multiple biological activities, including antiviral and anticancer effects. This paper comprehensively compiles all studies that have featured anti-HOHV properties of BBR along with promising preventive effects against the associated cancers. The mechanisms and pathways induced by BBR via targeting the herpesvirus life cycle and the pathogenesis of the linked malignancies are reviewed. Approaches to enhance the therapeutic efficacy of BBR and its use in clinical practice as an anti-herpesvirus drug are also discussed.

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.

Improving sciatic nerve regeneration by using alginate/chitosan hydrogel containing berberine

Peripheral nerve injuries are the common results of trauma that lead to pain and handicap in patients. Berberine due to its properties like antibiotic, immunostimulant, antitumor, antimotility, and positive effect on neurological disorders can be used to enhance peripheral nerve injuries. In this study, alginate/chitosan hydrogel containing different concentrations of berberine (0, 0.1, 1, 10% (w/v)) was created, evaluated, and applied as a scaffold for sciatic nerve regeneration. To prepare hydrogel, sodium alginate was dissolved in distilled water and cross-linked with CaCl2, and chitosan was dissolved in acetic acid and cross-linked with β-glycerol phosphate. The structure, release, swelling, weight loss, cytocompatibility, and hemocompatibility of the prepared hydrogels were assessed. The sciatic nerve crush was created in rats and fabricated hydrogels were injected, and functional analysis was used to evaluate their effectiveness. The results of physical characterization of the hydrogel indicated that the initial average pore size was about 39 μm and about 70% of the main weight of hydrogels was lost after incubation for 21 days and hemocompatibility of hydrogels was also confirmed. The MTT assay showed the cytocompatiblity of hydrogels and also indicated that berberine has dose-dependence effect on cell proliferation. The in vivo results showed the positive effect of berberine especially the hydrogel contained 1% of berberine on regeneration of sciatic nerve. Based on this study, Alg/Chit hydrogel can be applied as a treatment to heal peripheral nerve injuries. Graphical abstract.

Non-'classical' MEKs: A review of MEK3-7 inhibitors

The MAPK pathways are an enduring area of interest due to their essential roles in cell processes. Increased expression and activity can lead to a multitude of diseases, sparking research efforts in developing inhibitors against these kinases. Though great strides have been made in developing MEK1/2 inhibitors, there is a notable lack of chemical probes for MEK3-7, given their central role in stimuli response, cell growth, and development. This review summarizes the progress that has been made on developing small molecule probes for MEK3-7, the specific disease states in which they have been studied, and their potential to become novel therapeutics.

Berberine derivatives with a long alkyl chain branched by hydroxyl group and methoxycarbonyl group at 9-position show improved anti-proliferation activity and membrane permeability in A549 cells

Berberine (BBR) exhibits diverse bioactivities, including anticancer activity; but its poor druggability limits its applications. In this study, we designed and synthesized a series of 9-O position modified BBR derivatives aiming to improve its cell permeability and anticancer activity, utilizing a long alkyl chain branched by hydroxyl group and methoxycarbonyl group. Among these compounds, B10 showed 3.6-fold higher intracellular concentration than BBR, as well as 60-fold increased anti-proliferation activity against human lung cancer A549 cells compared with BBR. Treatment with B10 (1, 2 μM) induced apoptosis of A549 cells. Further investigations showed that B10 treatment dose-dependently affected mitochondrial functions, including oxygen consumption rate (OCR), mitochondrial membrane potential (MMP) and the morphology of mitochondria in A549 cells. Therefore, this work offers a new way for BBR structural modification through improving cell membrane permeability to affect mitochondrial functions and potential anti-tumor therapy in the future.

Repurposing of plant alkaloids for cancer therapy: Pharmacology and toxicology

Drug repurposing (or repositioning) is an emerging concept to use old drugs for new treatment indications. Phytochemicals isolated from medicinal plants have been largely neglected in this context, although their pharmacological activities have been well investigated in the past, and they may have considerable potentials for repositioning. A grand number of plant alkaloids inhibit syngeneic or xenograft tumor growth in vivo. Molecular modes of action in cancer cells include induction of cell cycle arrest, intrinsic and extrinsic apoptosis, autophagy, inhibition of angiogenesis and glycolysis, stress and anti-inflammatory responses, regulation of immune functions, cellular differentiation, and inhibition of invasion and metastasis. Numerous underlying signaling processes are affected by plant alkaloids. Furthermore, plant alkaloids suppress carcinogenesis, indicating chemopreventive properties. Some plant alkaloids reveal toxicities such as hepato-, nephro- or genotoxicity, which disqualifies them for repositioning purposes. Others even protect from hepatotoxicity or cardiotoxicity of xenobiotics and established anticancer drugs. The present survey of the published literature clearly demonstrates that plant alkaloids have the potential for repositioning in cancer therapy. Exploitation of the chemical diversity of natural alkaloids may enrich the candidate pool of compounds for cancer chemotherapy and -prevention. Their further preclinical and clinical development should follow the same stringent rules as for any other synthetic drug as well. Prospective randomized, placebo-controlled clinical phase I and II trials should be initiated to unravel the full potential of plant alkaloids for drug repositioning.

Cytotoxic and Proapoptotic Activity of Sanguinarine, Berberine, and Extracts of Chelidonium majus L. and Berberis thunbergii DC. toward Hematopoietic Cancer Cell Lines

Isoquinoline alkaloids belong to the toxic secondary metabolites occurring in plants of many families. The high biological activity makes these compounds promising agents for use in medicine, particularly as anticancer drugs. The aim of our study was to evaluate the cytotoxicity and proapoptotic activity of sanguinarine, berberine, and extracts of Chelidonium majus L. and Berberis thunbergii DC. IC10, IC50, and IC90 doses were established toward hematopoietic cancer cell lines using trypan blue staining. Alterations in the expression of 18 apoptosis-related genes in cells exposed to IC10, IC50, and IC90 were evaluated using real-time PCR. Sanguinarine and Chelidonium majus L. extract exhibit significant cytotoxicity against all studied cell lines. Lower cytotoxic activity was demonstrated for berberine. Berberis thunbergii DC. extract had no influence on cell viability. Berberine, sanguinarine, and Chelidonium majus L. extract altered the expression of apoptosis-related genes in all tested cell lines, indicating the induction of apoptosis. The presented study confirmed the substantial cytotoxicity and proapoptotic activity of sanguinarine, berberine, and Chelidonium majus L. extract toward the studied hematopoietic cell lines, which indicates the utility of these substances in anticancer therapy.

Berberine Effects on NFκB, HIF1A and NFE2L2/AP-1 Pathways in HeLa Cells

Background:

Berberine has multitudinous anti-cancer stem cells effects making it a highly promising candidate substance for the next-generation cancer therapy. However, berberine modes of action predispose it to significant side-effects that probably limit its clinical testing and application.

Materials and Methods:

HeLa cells were treated with two concentrations of berberine (30 and 100 µM) for 24 hours to assess the functioning of the NFE2L2/AP-1, NFκB and HIF1A pathways using 22 RNAs expression qPCR-based analysis.

Results:

Berberine effects appeared to be highly dose-dependent, with the lower concentration being capable of suppressing the NFκB functioning and the higher concentration causing severe signaling side-effects seen in the HIF1A pathway and the NFE2L2 sub-pathways, and especially and more importantly in the AP-1 sub-pathway.

Conclusion:

The results of the study suggest that berberine has clinically valuable anti-NFκB effects however jeopardized by its side effects on the HIF1A and especially NFE2L2/AP-1 pathways, its therapeutic window phenomenon and its cancer type-specificity. These, however, may be ameliorated using the cocktail approach, provided there is enough data on signaling effects of berberine.

Are polyphenol antioxidants at the root of medicinal plant anti-cancer success?

ETHNOPHARMACOLOGICAL RELEVANCE

Given the severe side effects associated with most of the conventional cancer medications, as well as the expanding body of evidence indicating secondary toxicity of these drugs, individuals with cancer are increasingly turning to natural alternatives. Similarly, the pharmaceutical industry is in search of natural products to treat cancer. An understanding of the specific active components in plant products with which anti-cancer efficacy is achieved is required for this research to move forward.

AIM OF THE STUDY

To integrate data from cancer-relatestudies on plant-derived products or extracts, to elucidate whether these products may have similar active ingredients and/or mechanisms of action, that can explain their efficacy. This review also includes a discussion of the methodological complexities and important considerations involved in accurate isolation and characterisation of active substances from plant material.

CONCLUSIONS

From the literature reviewed, most plant products with consistently reported anti-cancer efficacy contains high levels of polyphenols or other potent antioxidants and their mechanisms of action correlate to that reported for isolated antioxidants in the context of cancer. This suggests that natural products may indeed become the panacea against this chronic disease - either as therapeutic medicine strategy or to serve as templates for the design of novel synthetic drugs. The recommendation is made that antioxidant activity of plant actives and especially polyphenols, should be the focus of anti-cancer drug discovery initiatives. Lastly, researchers are advised to exploit current techniques of chemical compound characterisation when investigating polyphenol-rich plants to enable the easy consolidation of research findings from different laboratories.

Attenuation of CD47-SIRPα Signal in Cholangiocarcinoma Potentiates Tumor-Associated Macrophage-Mediated Phagocytosis and Suppresses Intrahepatic Metastasis

The involvement of chronic inflammation in cholangiocarcinoma (CCA) progression is well established. Cluster of differentiation 47 (CD47) is mutually expressed in various cancers and serves as a protective signal for phagocytic elimination. CD47 signaling blockage is a recent treatment strategy; however, little is known regarding CD47 in CCA. Therefore, the potential use of CD47 targeting in CCA was focused. CD47 was highly expressed in CCA compared to hepatocellular carcinoma (HCC). Disturbance of CD47-signal regulatory protein-α (SIRPα) interaction by blocking antibodies promoted the macrophage phagocytosis. The therapeutic potential of anti-CD47 therapy was demonstrated in liver metastatic model; alleviation of cancer colonization together with dense macrophage infiltrations was observed. The usefulness of anti-CD47 was emphasized by its universal facilitating macrophage activities. Moreover, increased production of inflammatory cytokines, such as IL-6 and IL-10, in macrophage exposed to CCA-conditioned media suggested that CCA alters macrophages toward cancer promotion. Taken together, interfering of CD47-SIRPα interaction promotes macrophage phagocytosis in all macrophage subtypes and consequently suppresses CCA growth and metastasis. The unique overexpression of CD47 in CCA but not HCC offers an exceptional opportunity for a targeted therapy. CD47 is therefore a novel target for CCA treatment.

Biology and management of primary effusion lymphoma

Primary effusion lymphoma (PEL) is a rare B-cell malignancy that most often occurs in immunocompromised patients, such as HIV-infected individuals and patients receiving organ transplantation. The main characteristic of PEL is neoplastic effusions in body cavities without detectable tumor masses. The onset of the disease is associated with latent infection of human herpes virus 8/Kaposi sarcoma–associated herpes virus, and the normal counterpart of tumor cells is B cells with plasmablastic differentiation. A condition of immunodeficiency and a usual absence of CD20 expression lead to the expectation of the lack of efficacy of anti-CD20 monoclonal antibody; clinical outcomes of the disease remain extremely poor, with an overall survival at 1 year of ∼30%. Although recent progress in antiretroviral therapy has improved outcomes of HIV-infected patients, its benefit is still limited in patients with PEL. Furthermore, the usual high expression of programmed death ligand 1 in tumor cells, one of the most important immune-checkpoint molecules, results in the immune escape of tumor cells from the host immune defense, which could be the underlying mechanism of poor treatment efficacy. Molecular-targeted therapies for the activating pathways in PEL, including NF-κB, JAK/STAT, and phosphatidylinositol 3-kinase/AKT, have emerged to treat this intractable disease. A combination of immunological recovery from immune deficiency, overcoming the immune escape, and the development of more effective drugs will be vital for improving the outcomes of PEL patients in the future.

Targeting oncogenic transcription factors by polyphenols: A novel approach for cancer therapy

Inflammation is one of the major causative factor of cancer and chronic inflammation is involved in all the major steps of cancer initiation, progression metastasis and drug resistance. The molecular mechanism of inflammation driven cancer is the complex interplay between oncogenic and tumor suppressive transcription factors which include FOXM1, NF-kB, STAT3, Wnt/β- Catenin, HIF-1α, NRF2, androgen and estrogen receptors. Several products derived from natural sources modulate the expression and activity of multiple transcription factors in various tumor models as evident from studies conducted in cell lines, pre-clinical models and clinical samples. Further combination of these natural products along with currently approved cancer therapies added an additional advantage and they considered as promising targets for prevention and treatment of inflammation and cancer. In this review we discuss the application of multi-targeting natural products by analyzing the literature and future directions for their plausible applications in drug discovery.

Viral Oncology: Molecular Biology and Pathogenesis

Oncoviruses are implicated in approximately 12% of all human cancers. A large number of the world's population harbors at least one of these oncoviruses, but only a small proportion of these individuals go on to develop cancer. The interplay between host and viral factors is a complex process that works together to create a microenvironment conducive to oncogenesis. In this review, the molecular biology and oncogenic pathways of established human oncoviruses will be discussed. Currently, there are seven recognized human oncoviruses, which include Epstein-Barr Virus (EBV), Human Papillomavirus (HPV), Hepatitis B and C viruses (HBV and HCV), Human T-cell lymphotropic virus-1 (HTLV-1), Human Herpesvirus-8 (HHV-8), and Merkel Cell Polyomavirus (MCPyV). Available and emerging therapies for these oncoviruses will be mentioned.

8-Cetylberberine inhibits growth of lung cancer in vitro and in vivo

AIMS

This study is aimed at detecting the anti-tumor efficacy of a new berberine (BBR) derivative 8-cetylberberine (HBBR), which has a significant improvement in hydrophobicity and pharmacological effects compared to BBR.

MAIN METHODS

The human non-small lung cancer cell line A549 and normal human lung epithelial cells (MRC-5) were cultured to observe inhibition in vitro. Cell viability was analyzed via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The effect of HBBR on cell cycle arrest and apoptosis were assessed by flow cytometry and western blotting. In animal studies, BALB/c nude mice were subcutaneously injected with A549 cells in the armpit and administrated with different dose of HBBR and BBR. The body weight, organ coefficient and tumor inhibitory rate were recorded to evaluate the effect of HBBR in vivo.

KEY FINDINGS

The data showed that HBBR induced G1-phase cycle arrest by interfering with the expression of Cyclins D1 and Cyclin E1, increased apoptosis by inducing caspase pathway, and probably inhibited the PI3K/Akt pathway in A549 cells. In addition, animal experiments proved that oral administration of HBBR at a dose of 10mg/kg could significantly inhibit tumor growth, which is stronger than the 120mg/kg dose of BBR treatment.

SIGNIFICANCE

Our results suggest that HBBR showed a significantly higher anti-tumor efficacy than BBR in vitro and in vivo and could be a potential therapy for lung cancers.

Berberine induces oxidative DNA damage and impairs homologous recombination repair in ovarian cancer cells to confer increased sensitivity to PARP inhibition

Many cancer drugs exert their therapeutic effect by inducing oxidative stress in the cancer cells. Oxidative stress compromises cell survival by inflicting lesions in macromolecules like DNA. Cancer cells rely on enhanced antioxidant metabolism and increased DNA repair function to survive oxidative assault. PARP1, a protein that senses DNA-strand breaks and orchestrates their repair, has an important role in the repair of oxidative DNA damage. Berberine, an alkaloid compound present in many herbal plants, is capable of inducing oxidative DNA damage and downregulating homologous recombination repair (HRR) in cancer cells. In this study, we demonstrated that berberine and PARP inhibitor niraparib have a synthetic lethal effect on ovarian cancer cells. Oxidative DNA damage was greatly induced by berberine in ovarian cancer cells. In addition, the level of RAD51 and the capacity of HRR were also reduced by berberine. Correspondingly, PARP became hyperactivated in response to berberine treatment. Cancer cells treated with berberine and niraparib in combination exhibited greatly increased apoptosis and remarkably reduced tumor growth in vivo. Together, the results indicate that by inducing oxidative DNA damage and downregulating HRR in cancer cells berberine is able to further sensitize cancer cells to PARP inhibition. Our findings demonstrate a potential therapeutic value of combined application of berberine and PARP inhibitors in ovarian cancer treatment.

Restoring PU.1 induces apoptosis and modulates viral transactivation via interferon-stimulated genes in primary effusion lymphoma

Primary effusion lymphoma (PEL), which is an aggressive subgroup of B-cell lymphoma associated with Kaposi sarcoma-associated herpes virus/human herpes virus-8, is refractory to the standard treatment, and exhibits a poor survival. Although PU.1 is downregulated in PEL, the potential role of its reduction remains to be elucidated. In this investigation, we analyzed the DNA methylation of PU.1 cis-regulatory elements in PEL and the effect of restoring PU.1 on PEL cells. The mRNA level of PU.1 was downregulated in PEL cells. The methylated promoter and enhancer regions of the PU.1 gene were detected in PEL cells. Suppression of cell growth and apoptosis were caused by the restoration of PU.1 in PEL cells. A microarray analysis revealed that interferon-stimulated genes (ISGs) including pro-apoptotic ISGs were strongly increased in BCBL-1 cells after the induction of PU.1. Reporter assays showed that PU.1 transactivated pro-apoptotic ISG promoters, such as the XAF1, OAS1 and TRAIL promoters. Mutations at the PU.1 binding sequences suppressed its transactivation. We confirmed the binding of PU.1 to the XAF1, OAS1 and TRAIL promoters in a chromatin immunoprecipitation assay. PU.1 suppressed ORF57 activation by inducing IRF7. The reinduction of PU.1 reduced formation of ascites and lymphoma cell infiltration of distant organs in PEL xenograft model mice. Collectively, PU.1 has a role in tumor suppression in PEL and its down-regulation is associated with PEL development. Restoring PU.1 with demethylation agents may be a novel therapeutic approach for PEL.

Berberine inhibits the proliferation of human nasopharyngeal carcinoma cells via an Epstein-Barr virus nuclear antigen 1-dependent mechanism

Nasopharyngeal carcinoma (NPC) is a malignancy derived from the epithelial cells of the nasopharynx cavity, and is closely associated with Epstein-Barr virus (EBV) infection. In addition to NPC, EBV causes various human malignancies, such as gastric cancer, hematological tumors and lymphoepithelioma-like carcinomas. Epstein-Barr nuclear antigen 1 (EBNA1) encoded by EBV is indispensable for replication, partition, transcription and maintenance of viral genomes. Berberine, a naturally occurring isoquinoline alkaloid, shows anti-inflammatory, anticholinergic, antioxidative, and anticancer activities. In the present study, the antitumor effect of berberine was studied. Cell Counting Kit-8 (CCK-8) assays were performed to demonstrate whether the proliferation of EBV-positive NPC cells was inhibited by berberine. Flow cytometric results revealed that berberine induced cell cycle arrest and apoptosis. Quantitative-PCR and western blotting results indicated that berberine decreased the expression of EBNA1 at both the mRNA and protein levels in the EBV-positive NPC cells. The function of EBNA1 promoter Qp which is to drive EBNA1 transcription in type Ⅱ latent infection was strongly suppressed by berberine. Overexpression of EBNA1 attenuated this inhibitory effect. Berberine also suppressed the activity of signal transducer and activator of transcription 3 which is a new therapeutic target in a series of malignancies, including NPC. Viral titer experiments demonstrated that berberine decreased the production of virions in HONE1 and HK1-EBV cells. In a mouse xenograft model of NPC induced by HONE1 cells, berberine significantly inhibited tumor formation. Altogether, these results indicate that berberine decreases the expression of EBNA1 and exhibits an antitumor effect against NPC both in vitro and in vivo.

Up-regulation of microRNA-491-5p suppresses cell proliferation and promotes apoptosis by targeting FOXP4 in human osteosarcoma

BACKGROUND AND OBJECTIVES

MicroRNAs are small non-coding RNAs involved in pathogenesis and progression of human malignancies. MicroRNA-491-5p (miR-491-5p) is down-regulated in many human cancers where it would serve as a tumour suppressor. However, the role played by miR-491-5p in pathogenesis of human osteosarcoma has remained largely unknown. This study has been conducted to examine effects of miR-491-5p on migration and proliferation of cells of the SAOS-2 and MG63 osteosarcoma lines, and mechanisms of those effects.

MATERIALS AND METHODS

Levels of miR-491-5p expression in osteosarcoma tissues and in human osteosarcoma cell lines were studied using qualitative real-time polymerase chain reaction (qRT-PCR) methods. Cell viability was detected using the CCK-8 and EdU assays, while the transwell assay was used to evaluate migration and invasion. Apoptosis was analysed uing flow cytometry and the Hoechst 33342 nuclear staining method. A dual-luciferase reporter system was used to confirm the target gene of miR-491-5p. The electrophoretic mobility shift assay (EMSA) with DIG-labelled double-stranded FOXP4 oligonucleotides was used to confirm whether or not miR-491-5p suppressed FOXP4 activation.

RESULTS

Cells of osteosarcoma tissues and cell lines had low levels of miR-491-5p expression, but high levels of forkhead-box P4 (FOXP4) expression. Transfection of SAOS-2 and MG63 cells with miR-491-5p mimics inhibited expression of FOXP4 protein, which suppressed cell growth and migration, but induced apoptosis. Dual-luciferase reporter assays confirmed FOXP4 as the target gene for miR-491-5p. Overexpression of miR-491-5p suppressed FOXP4 activity in SAOS-2 and MG63 cells. Knockdown of FOXP4 in SAOS-2 and MG63 cells using an RNAi strategy resulted in reduced levels of cell proliferation and migration, but increased levels of apoptosis.

CONCLUSION

Our in vitro studies showed that up-regulation of miR-491-5p suppressed proliferation of the human osteosarcoma cells and induced apoptosis by targeting FOXP4. These findings suggest that miR-491-5p could be further studied as a potential clinical diagnostic or predictive biomarker for human osteosarcoma.

A potential role of the NOD genetic background in mouse peritoneal macrophages for the development of primary effusion lymphoma

Severe immunodeficient mice have become invaluable tools in human stem cell and tumor research. In this study, we compared the phagocytic activity of peritoneal macrophages against primary effusion lymphoma (PEL) among Rag-2/Jak3 double-deficient (Rag-2(-/-)Jak3(-/-)) mice with NOD and non-NOD (Balb/c and C57/BL6). We also evaluated lymphomatous effusion and infiltration in a PEL xenograft mouse model using these severe immunodeficient mice. In the phagocytic assay, peritoneal macrophages in the NOD background phagocytosed CFSE-labeled BCBL-1, a PEL cell line, less efficiently than those in the non-NOD background. BCBL-1 cells were successfully engrafted into both the NOD background and non-NOD background; however, the volume of ascites of the NOD background was significantly higher than that of the non-NOD background. Moreover, the organ invasion of PEL cells was suppressed in non-NOD background mice. Thus, the NOD genetic background is considered to contribute to more lymphomatous effusion and the infiltration of PEL cells than a non-NOD background. Our results showed that the NOD background allowed more lymphomatous effusion and infiltration than other backgrounds and peritoneal macrophages played a critical role in preventing the growth and infiltration of PEL cells.

Triptolide decreases expression of latency-associated nuclear antigen 1 and reduces viral titers in Kaposi's sarcoma-associated and herpesvirus-related primary effusion lymphoma cells

Kaposi's sarcoma-associated herpesvirus (KSHV) can establish a life-long persistence in the host after primary infection and is associated with certain malignancies, which are resistant to conventional chemotherapeutic agents with a poor prognosis. Latency-associated nuclear antigen 1 (LANA1) encoded by KSHV is essential for segregation, replication and maintenance of viral genome. In addition, LANA1 upregulates the transcriptional activity of signal transducer and activator of transcription 3 (STAT3), which plays an important role in promoting survival of KSHV-associated primary effusion lymphoma (PEL) cells. Furthermore, LANA1 mediates transcriptional modulation of KSHV and host genome in host cells. In the present study, the antitumor effect of triptolide was assessed. CCK-8 assays were performed to demonstrate that the proliferations of PEL cells were efficiently inhibited by triptolide in a dose- and time-dependent manner. Flow cytometric results indicated that triptolide induced cell cycle arrest and apoptosis. Western blot results suggested that triptolide downregulated LANA1 expression and reduced half-life of LANA1 in the KSHV-infected malignant cells. Viral titer experiments indicated that triptolide treatment impaired the number of viral DNA copies and the production of virions in BCBL-1 cells. Triptolide also suppressed STAT3 activity and inhibited secretion of IL-6 in PEL cells. In a mouse xenograft model of primary effusion lymphoma by BCBL-1 cells, triptolide treatment significantly inhibited ascites formation and diffused organ infiltration. These results indicate that triptolide impairs the expression of LANA1 and shows antitumor activity against PEL in vitro and in vivo. Triptolide may be a potential agent for treatment of PEL.

Berberis libanotica extract targets NF-κB/COX-2, PI3K/Akt and mitochondrial/caspase signalling to induce human erythroleukemia cell apoptosis

The aim of this study was to describe and understand the relationship between cyclooxygenase-2 (COX-2) expression and apoptosis rate in erythroleukemia cells after apoptosis induction by Berberis libanotica (Bl) extract. To achieve this goal we used erythroleukemia cell lines expressing COX‑2 (HEL cell line) or not (K562 cell line). Moreover, we made use of COX‑2 cDNA to overexpress COX‑2 in K562 cells. In light of the reported chemopreventive and chemosensitive effects of natural products on various tumor cells and animal models, we postulated that our Bl extract may mediate their effects through apoptosis induction with suppression of cell survival pathways. Our study is the first report on the specific examination of intrinsic apoptosis and Akt/NF-κB/COX‑2 pathways in human erythroleukemia cells upon Bl extract exposure. Even if Bl extract induced apoptosis of three human erythroleukemia cell lines, a dominant effect of Bl extract treatment on K562 cells was observed resulting in activation of the late markers of apoptosis with caspase-3 activation, PARP cleavage and DNA fragmentation. Whereas, we showed that Bl extract reduced significantly expression of COX‑2 by a dose-dependent manner in HEL and K562 (COX‑2+) cells. Furthermore, in regard to our results, it is clear that the simultaneous inhibition of Akt and NF-κB signalling can significantly contribute to the anticancer effects of Bl extract in human erythroleukemia cells. We observed that the Bl extract is clearly more active than the berberine alone on the induction of DNA fragmentation in human erythro-leukemia cells.

Berberine inhibits the proliferation of prostate cancer cells and induces G₀/G₁ or G₂/M phase arrest at different concentrations

Prostate cancer is the second most common disease of the male reproductive system. Berberine is a quaternary ammonium salt that is extracted from plants. The aim of the current study was to explore the antitumor activity of berberine in prostate cancer cells and identify the underlying mechanism of its effects. PC3 human and RM‑1 mouse prostate cancer cells were treated with increasing concentrations of berberine, followed by analysis of the cell viability with an MTT assay. The results demonstrated that berberine markedly inhibited the proliferation of PC3 and RM‑1 cells, and that the inhibitory effects to PC3 and RM‑1 were enhanced in a concentration‑ and time‑dependent manner. Flow cytometry was used to analyze the cell cycle of PC3 human prostate cancer cells, and the results demonstrated that G0/G1 phase arrest was induced following treatment with 10 µM berberine (P<0.05). However, with an increased concentration of berberine (50 µM) the survival rate of PC3 cells at the G2/M phase was significantly increased compared with the cells treated with 10 µM berberine, which suggests that different cell cycle signaling pathways were activated when PC3 cells were treated with low and high concentrations of berberine. Thus, clarifying the mechanism underlying these effects in prostate cancer may provide novel molecular targets for prostate cancer therapy.

The antitumor effects of methyl-β-cyclodextrin against primary effusion lymphoma via the depletion of cholesterol from lipid rafts

Primary effusion lymphoma (PEL) is a subtype of aggressive and chemotherapy-resistant non-Hodgkin lymphoma that occurs predominantly in patients with advanced AIDS. In this study, we examined the antitumor activity of methyl-β-cyclodextrin (M-β-CyD) in vitro and in vivo. M-β-CyD quickly induced caspase-dependent apoptosis in PEL cells via cholesterol depletion from the plasma membrane. In a PEL xenograft mouse model, M-β-CyD significantly inhibited the growth and invasion of PEL cells without apparent adverse effects. These results strongly suggest that M-β-CyD has the potential to be an effective antitumor agent against PEL.

Targeting VEGF and interleukin-6 for controlling malignant effusion of primary effusion lymphoma

PURPOSE

Primary effusion lymphoma (PEL) is an aggressive subtype of non-Hodgkin lymphoma that shows malignant effusion most commonly seen in advanced AIDS patients. In this study, we clarified the potential role of VEGF and IL-6 in PEL fluid retention and evaluated the efficacy of humanized anti-VEGF monoclonal antibody (mAb), bevacizumab, and humanized anti-IL-6 receptor mAb, tocilizumab, against PEL.

METHODS

The production of VEGF and IL-6, and the expression of IL-6Rα in PEL cell lines were examined. The antiproliferative effect of bevacizumab and tocilizumab on PEL cells was evaluated in vitro. The effect of tocilizumab on VEGF was also examined. An intraperitoneal xenograft mouse model was used for in vivo efficacy.

RESULTS

Although we found the production of VEGF and IL-6, and the expression of IL-6Rα in PEL cell lines, bevacizumab and tocilizumab did not inhibit the proliferation of PEL cells in vitro. Tocilizumab decreased VEGF mRNA and VEGF production by inhibiting Stat3 phosphorylation and Stat3 binding to VEGF promoter. In a PEL xenograft mouse model that showed profuse ascites, bevacizumab suppressed ascites formation completely, indicating the critical role of VEGF for PEL fluid retention. Tocilizumab also significantly inhibited ascites formation in vivo. Moreover, these mAbs improved the overall survival of treated mice.

CONCLUSIONS

IL-6-VEGF axis contributed to fluid retention, and bevacizumab and tocilizumab could be effective molecular targeting therapies for PEL.

Current status of treatment for primary effusion lymphoma

Primary effusion lymphoma (PEL) is a rare and aggressive B-cell non-Hodgkin's lymphoma that usually presents with malignant effusions without tumor masses. An extracavitary or solid variant of PEL has also been described. Human herpes virus 8/Kaposi sarcoma-associated herpes virus (HHV-8/KSHV) is universally associated with the pathogenesis of PEL. More than 70% of cases occur with concurrent Epstein-Barr virus infection, but its relation to the pathogenesis is unknown. Patients are found in the context of immunosuppressive states (HIV-1 infection, post-organ transplantation). PEL is usually treated with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone)-like chemotherapy with antiretroviral therapy if HIV-1 is positive. However, it is generally resistant to chemotherapy with a short median survival of less than 6 months. The optimal treatment for PEL has not been established yet. More intensive chemotherapy, such as dose-adjusted EPOCH (DA-EPOCH; etoposide, prednisone, vincristine, cyclophosphamide and doxorubicin) and CDE (cyclophosphamide, doxorubicin, etoposide) are expected to show a favorable prognosis. Recently, the molecular steps in KSHV/HHV-8-driven oncogenesis have begun to be revealed, and molecular targeting therapies such as proteasome, NF-κB, cytokines and surface antigens would provide evidence for their clinical use.

Multiple effects of berberine derivatives on colon cancer cells

The pharmacological use of the plant alkaloid berberine is based on its antibacterial and anti-inflammatory properties; recently, anticancer activity has been attributed to this compound. To exploit this interesting feature, we synthesized three berberine derivatives, namely, NAX012, NAX014, and NAX018, and we tested their effects on two human colon carcinoma cell lines, that is, HCT116 and SW613-B3, which are characterized by wt and mutated p53, respectively. We observed that cell proliferation is more affected by cell treatment with the derivatives than with the lead compound; moreover, the derivatives proved to induce cell cycle arrest and cell death through apoptosis, thus suggesting that they could be promising anticancer drugs. Finally, we detected typical signs of autophagy in cells treated with berberine derivatives.

Berberine regulates AMP-activated protein kinase signaling pathways and inhibits colon tumorigenesis in mice

Colorectal cancer, a leading cause of cancer death, has been linked to inflammation and obesity. Berberine, an isoquinoline alkaloid, possesses anti-inflammatory, anti-diabetes and anti-tumor properties. In the azoxymethane initiated and dextran sulfate sodium (AOM/DSS) promoted colorectal carcinogenesis mouse model, berberine treated mice showed a 60% reduction in tumor number (P = 0.009), a 48% reduction in tumors <2 mm, (P = 0.05); 94% reduction in tumors 2-4 mm, (P = 0.001), and 100% reduction in tumors >4 mm (P = 0.02) compared to vehicle treated mice. Berberine also decreased AOM/DSS induced Ki-67 and COX-2 expression. In vitro analysis showed that in addition to its anti-proliferation activity, berberine also induced apoptosis in colorectal cancer cell lines. Berberine activated AMP-activated protein kinase (AMPK), a major regulator of metabolic pathways, and inhibited mammalian target of rapamycin (mTOR), a downstream target of AMPK. Furthermore, 4E-binding protein-1 and p70 ribosomal S6 kinases, downstream targets of mTOR, were down regulated by berberine treatment. Berberine did not affect Liver kinase B1 (LKB1) activity or the mitogen-activated protein kinase pathway. Berberine inhibited Nuclear Factor kappa-B (NF-κB) activity, reduced the expression of cyclin D1 and survivin, induced phosphorylation of p53 and increased caspase-3 cleavage in vitro. Berberine inhibition of mTOR activity and p53 phosphorylation was found to be AMPK dependent, while inhibition NF-κB was AMPK independent. In vivo, berberine also activated AMPK, inhibited mTOR and p65 phosphorylation and activated caspase-3 cleavage. Our data suggests that berberine suppresses colon epithelial proliferation and tumorigenesis via AMPK dependent inhibition of mTOR activity and AMPK independent inhibition of NF-κB.

A Protoberberine derivative HWY336 selectively inhibits MKK4 and MKK7 in mammalian cells: the importance of activation loop on selectivity

A protoberberine derivative library was used to search for selective inhibitors against kinases of the mitogen-activated protein kinase (MAPK) cascades in mammalian cells. Among kinases in mammalian MAPK pathways, we identified a compound (HWY336) that selectively inhibits kinase activity of mitogen-activated protein kinase kinase 4 and 7 (MKK4 and MKK7). The IC₅₀ of HWY336 was 6 µM for MKK4 and 10 µM for MKK7 in vitro. HWY336 bound to both kinases reversibly via noncovalent interactions, and inhibited their activity by interfering with access of a protein substrate to its binding site. The binding affinity of HWY336 to MKK4 was measured by surface plasmon resonance to determine a dissociation constant (K_d) of 3.2 µM. When mammalian cells were treated with HWY336, MKK4 and MKK7 were selectively inhibited, resulting in inhibition of c-Jun NH₂-terminal protein kinases in vivo. The structural model of HWY336 bound to either MKK4 or MKK7 predicted that HWY336 was docked to the activation loop, which is adjacent to the substrate binding site. This model suggested the importance of the activation loop of MKKs in HWY336 selectivity. We verified this model by mutating three critical residues within this loop of MKK4 to the corresponding residues in MKK3. The mutant MKK4 displayed similar kinase activity as wild-type kinase, but its activity was not inhibited by HWY336 compared to wild-type MKK4. We propose that the specific association of HWY336 to the activation loop of MKK4/MKK7 is responsible for its selective inhibition.

Efficacy of anti-CD47 antibody-mediated phagocytosis with macrophages against primary effusion lymphoma

BACKGROUND

Recently, the critical role of CD47 on the surface of resistant cancer cells has been proposed in their evasion of immunosurveillance. Primary effusion lymphoma (PEL) is a subtype of aggressive non-Hodgkin lymphoma that shows serous lymphomatous effusion in body cavities, especially in advanced acquired immunodeficiency syndrome (AIDS). PEL is resistant to conventional chemotherapy and has a poor prognosis. In this study, we evaluated the effect of anti-CD47 antibody (Ab) on PEL in vitro and in vivo.

METHODS

Surface CD47 of PEL cell lines was examined by flow cytometry. Efficacy of knocking down CD47 or anti-CD47 Ab-mediated phagocytosis against PEL was evaluated using mouse peritoneal macrophages and human macrophages in vitro. Primary PEL cells were injected intraperitoneally into NOD/Rag-2/Jak3 double-deficient (NRJ) mice to establish a direct xenograft mouse model.

RESULTS

Surface CD47 of PEL cell lines was highly expressed. Knocking down CD47 and anti-CD47 Ab promoted phagocytic activities of macrophages in a CD47 expression-dependent manner in vitro. Treatment with anti-CD47 Ab inhibited ascite formation and organ invasion completely in vivo compared with control IgG-treated mice.

CONCLUSION

CD47 plays the pivotal role in the immune evasion of PEL cells in body cavities. Therapeutic antibody targeting of CD47 could be an effective therapy for PEL.

Diethyldithiocarbamate suppresses an NF-kappaB dependent metastatic pathway in cholangiocarcinoma cells

Cholangiocarcinoma (CCA) is a tumor of biliary ducts, which has a high mortality rate and dismal prognosis. Constitutively activation of the transcription factor nuclear factor kappa-B (NF-κB) has been previously demonstrated in CCA. It is therefore a potential target for CCA treatment. Effects of diethyldithiocarbamate (DDTC) on NF-κB-dependent apoptosis induction in cancer have been reported; however, anti-metastasis has never been addressed. Therefore, here the focus was on DDTC effects on CCA migration and adhesion. Anti-proliferation, anti-migration and anti-adhesion activities were determined in CCA cell lines, along with p65 protein levels and function. NF-κB target gene expression was determined by quantitative RT-PCR. DDTC inhibited CCA cell proliferation. Suppression of migration and adhesion were observed prior to anti-CCA proliferation. These effects were related to decreased p65, reduction in NF-κB DNA binding, and impaired activity. Moreover, suppression of ICAM-1 expression supported NF-kB-dependent anti-metastatic effects of DDTC. Taken together, DDTC suppression of CCA migration and adhesion through inhibition of NF-κB signaling pathway is suggested from the current study. This might be a promising treatment choice against CCA metastasis.

Primary effusion lymphoma in an elderly patient effectively treated by lenalidomide: case report and review of literature

Primary effusion lymphoma (PEL) is a rare aggressive subset of non-Hodgkin B-cell lymphoma. It is caused by Kaposi sarcoma-associated herpesvirus/human herpesvirus type 8 (KSHV/HHV8). It occurs mainly, but not exclusively, in HIV-positive patients. PEL predominantly develops in serous cavities and occasionally in extracavitary regions. PEL carries a very poor prognosis with a median survival time of <6 months. Indeed, currently used treatment modalities such as CHOP chemotherapy are far from achieving complete and sustainable remission. Therefore, there is no clear standard of care established in the treatment of PEL patients, stressing the need for novel-targeted approaches. Here, we have attempted a comprehensive assessment of the treatment of PEL, discussed avant-garde therapies and updated the state of preclinical research with promising clinical applications in the field. These include inhibitors of viral replication, modulators of cell signaling and inflammation, nuclear factor kappa B (NF-κB) and histone deacetylase inhibitors, and recently the combination of arsenic trioxide and interferon-alpha. Some of these targeted therapies have not yet reached clinical studies, although others were used in a few individual case reports with low numbers of patients. We also describe the first case of a 77-year-old, HIV-negative, HHV8-positive patient diagnosed with PEL limited to the pleural and peritoneal cavities. He received lenalidomide 25 mg/day for 21 days every 28 days. Treatment was well tolerated with no side effects. He rapidly improved after 1 month of treatment and progressively achieved complete remission persistent after 18 months of therapy. We believe that this review will bridge an important gap between classical chemotherapy and modern approaches of targeted therapy. Finally, our findings warrant further evaluation of lenalidomide in future prospective clinical studies.

Comparative analysis of ER stress response into HIV protease inhibitors: lopinavir but not darunavir induces potent ER stress response via ROS/JNK pathway

HIV protease inhibitor (PI)-induced ER stress has been associated with adverse effects. Although it is a serious clinical problem for HIV/AIDS patients, comparative analyses of ER stress induction by clinically used PIs have rarely been done. Especially, there is no report on the differential ER stress response between lopinavir (LPV) and darunavir (DRV), although these PIs are the most clinically used PIs. We show here that LPV induces the most potent CHOP expression, ER stress marker, among the 9 Food and Drug Administration (FDA)-approved PIs in human peripheral blood mononuclear cells, several human epithelial cells, and mouse embryonic fibroblasts. LPV induced the most potent ROS production and JNK activation in 9 PIs. A comparison among the most clinically used PIs, ritonavir (RTV), LPV, and DRV, revealed that LPV potently and RTV moderately but not DRV induced ER stress via ROS-dependent JNK activation rather than proteasome inhibition. Finally, we analyzed ER stress induction in tissues of mice intraperitoneally injected with RTV, LPV, and DRV. RTV and LPV but not DRV showed ER stress induction in several mice tissues. In conclusion, we first identify LPV as the most potent ER stress inducing PI among 9 FDA-approved PIs in human cells, and although clinical verification is necessary, we show here that DRV has the advantage of less ROS and ER stress induction potential compared with LPV in vitro and in vivo.

Combination of arsenic and interferon-α inhibits expression of KSHV latent transcripts and synergistically improves survival of mice with primary effusion lymphomas

Background

Kaposi sarcoma-associated herpesvirus (KSHV) is the etiologic agent of primary effusion lymphomas (PEL). PEL cell lines infected with KSHV, but negative for Epstein-Barr virus have a tumorigenic potential in non-obese diabetic/severe combined immunodeficient mice and result in efficient engraftment and formation of malignant ascites with notable abdominal distension, consistent with the clinical manifestations of PEL in humans.

Methodology/Principal Findings

Using this preclinical mouse model, we demonstrate that the combination of arsenic trioxide and interferon-alpha (IFN) inhibits proliferation, induces apoptosis and downregulates the latent viral transcripts LANA-1, v-FLIP and v-Cyc in PEL cells derived from malignant ascites. Furthermore, this combination decreases the peritoneal volume and synergistically increases survival of PEL mice.

Conclusion/Significance

These results provide a promising rationale for the therapeutic use of arsenic/IFN in PEL patients.

Berberine Targets AP-2/hTERT, NF-κB/COX-2, HIF-1α/VEGF and Cytochrome-c/Caspase Signaling to Suppress Human Cancer Cell Growth

Berberine (BBR), an isoquinoline derivative alkaloid isolated from Chinese herbs, has a long history of uses for the treatment of multiple diseases, including cancers. However, the precise mechanisms of actions of BBR in human lung cancer cells remain unclear. In this study, we investigated the molecular mechanisms by which BBR inhibits cell growth in human non-small-cell lung cancer (NSCLC) cells. Treatment with BBR promoted cell morphology change, inhibited cell migration, proliferation and colony formation, and induced cell apoptosis. Further molecular mechanism study showed that BBR simultaneously targeted multiple cell signaling pathways to inhibit NSCLC cell growth. Treatment with BBR inhibited AP-2α and AP-2β expression and abrogated their binding on hTERT promoters, thereby inhibiting hTERT expression. Knockdown of AP-2α and AP-2β by siRNA considerably augmented the BBR-mediated inhibition of cell growth. BBR also suppressed the nuclear translocation of p50/p65 NF-κB proteins and their binding to COX-2 promoter, causing inhibition of COX-2. BBR also downregulated HIF-1α and VEGF expression and inhibited Akt and ERK phosphorylation. Knockdown of HIF-1α by siRNA considerably augmented the BBR-mediated inhibition of cell growth. Moreover, BBR treatment triggered cytochrome-c release from mitochondrial inter-membrane space into cytosol, promoted cleavage of caspase and PARP, and affected expression of BAX and Bcl-2, thereby activating apoptotic pathway. Taken together, these results demonstrated that BBR inhibited NSCLC cell growth by simultaneously targeting AP-2/hTERT, NF-κB/COX-2, HIF-1α/VEGF, PI3K/AKT, Raf/MEK/ERK and cytochrome-c/caspase signaling pathways. Our findings provide new insights into understanding the anticancer mechanisms of BBR in human lung cancer therapy.

Establishment of a CD4-positive cell line from an AIDS-related primary effusion lymphoma

Primary effusion lymphoma (PEL) presents as a serous lymphomatous effusion without tumor masses exclusively in body cavities and mainly occurs in human immunodeficiency virus-1 (HIV-1)-infected patients. We established a new PEL cell line, designated GTO, from the pericardial effusion of a 39-year-old Japanese patient with acquired immunodeficiency syndrome-related PEL. This cell line was infected with human herpesvirus-8, but not with Epstein-Barr virus. Southern blot hybridization demonstrated that GTO cells display monoclonal rearrangement of the IgH gene, suggesting clonal B cell proliferation. GTO cells weakly express or lack T cell-associated markers (CD3, CD5, CD8), the majority of B cell-associated markers (CD19, CD20, CD21, CD79a), the α chains of β 2 integrins (CD11a, CD11b, CD11c), HLA-DR, CD30, and surface immunoglobulin (sIgM, sIgG sIgκ, sIgλ), TCR (α/β, γδ), but express CD45, and post-germinal center B cell/plasma cell-associated antigens (CD38, CD138). They also express a high level of cell-surface CD4 and can be infected by HIV-1. Immunodeficient mice intraperitoneally xenografted with GTO cells developed ascites containing lymphoma cells. The establishment of GTO and a GTO xenograft mouse model may help to provide insights toward a better understanding of the pathogenesis of PEL and the relationship between HIV-1 and HHV-8.

Site-specific phosphorylation of the DNA damage response mediator rad9 by cyclin-dependent kinases regulates activation of checkpoint kinase 1

The mediators of the DNA damage response (DDR) are highly phosphorylated by kinases that control cell proliferation, but little is known about the role of this regulation. Here we show that cell cycle phosphorylation of the prototypical DDR mediator Saccharomyces cerevisiae Rad9 depends on cyclin-dependent kinase (CDK) complexes. We find that a specific G2/M form of Cdc28 can phosphorylate in vitro the N-terminal region of Rad9 on nine consensus CDK phosphorylation sites. We show that the integrity of CDK consensus sites and the activity of Cdc28 are required for both the activation of the Chk1 checkpoint kinase and its interaction with Rad9. We have identified T125 and T143 as important residues in Rad9 for this Rad9/Chk1 interaction. Phosphorylation of T143 is the most important feature promoting Rad9/Chk1 interaction, while the much more abundant phosphorylation of the neighbouring T125 residue impedes the Rad9/Chk1 interaction. We suggest a novel model for Chk1 activation where Cdc28 regulates the constitutive interaction of Rad9 and Chk1. The Rad9/Chk1 complex is then recruited at sites of DNA damage where activation of Chk1 requires additional DDR–specific protein kinases.

Human cells activate the DNA damage response (DDR) to repair DNA damage and to prevent cells with DNA damage from proliferating. Alterations to the DDR are strongly implicated in the development of cancer. Using the budding yeast model system, we have studied how the regulation of the key DDR component Rad9 is integrated into cell cycle control. The cyclin-dependent kinase Cdc28 that regulates the yeast cell cycle also extensively phosphorylates Rad9 during cell cycle progression. We show here that Cdc28 controls Rad9 function in the activation of the important downstream DNA damage effector kinase Chk1. Two sites of phosphorylation in the N-terminus of Rad9 are crucial for the physical interaction between Rad9 and Chk1 regulated by Cdc28. We propose a novel model for Chk1 activation whereby a subset of Rad9 and Chk1 interacts constitutively in the absence of DNA damage. The Rad9/Chk1 complex is recruited to sites of DNA damage where activation of Chk1 involves additional DDR–specific protein kinases. Human cells contain multiple Rad9-like proteins that are also known to be cell cycle phosphorylated in the absence of exogenous DNA damage, suggesting that our observations may have important implications for DDR regulation in human cells.