A New Humanized Mouse Model Mimics Humans in Lacking α-Gal Epitopes and Secreting Anti-Gal Antibodies.

Mice have been used as accepted tools for investigating complex human diseases and new drug therapies because of their shared genetics and anatomical characteristics with humans. However, the tissues in mice are different from humans in that human cells have a natural mutation in the α1,3 galactosyltransferase (α1,3GT) gene and lack α-Gal epitopes on glycosylated proteins, whereas mice and other nonprimate mammals express this epitope. The lack of α-Gal epitopes in humans results in the loss of immune tolerance to this epitope and production of abundant natural anti-Gal Abs. These natural anti-Gal Abs can be used as an adjuvant to enhance processing of vaccine epitopes to APCs. However, wild-type mice and all existing humanized mouse models cannot be used to test the efficacy of vaccines expressing α-Gal epitopes because they express α-Gal epitopes and lack anti-Gal Abs. Therefore, in an effort to bridge the gap between the mouse models and humans, we developed a new humanized mouse model that mimics humans in that it lacks α-Gal epitopes and secretes human anti-Gal Abs. The new humanized mouse model (Hu-NSG/α-Galnull) is designed to be used for preclinical evaluations of viral and tumor vaccines based on α-Gal epitopes, human-specific immune responses, xenotransplantation studies, and in vivo biomaterials evaluation. To our knowledge, our new Hu-NSG/α-Galnull is the first available humanized mouse model with such features.

Neoplastic reprogramming of patient-derived adipose stem cells by prostate cancer cell-associated exosomes.

Emerging evidence suggests that mesenchymal stem cells (MSCs) are often recruited to tumor sites but their functional significance in tumor growth and disease progression remains elusive. Herein we report that prostate cancer (PC) cell microenvironment subverts PC patient adipose-derived stem cells (pASCs) to undergo neoplastic transformation. Unlike normal ASCs, the pASCs primed with PC cell conditioned media (CM) formed prostate-like neoplastic lesions in vivo and reproduced aggressive tumors in secondary recipients. The pASC tumors acquired cytogenetic aberrations and mesenchymal-to-epithelial transition and expressed epithelial, neoplastic, and vasculogenic markers reminiscent of molecular features of PC tumor xenografts. Our mechanistic studies revealed that PC cell-derived exosomes are sufficient to recapitulate formation of prostate tumorigenic mimicry generated by CM-primed pASCs in vivo. In addition to downregulation of the large tumor suppressor homolog2 and the programmed cell death protein 4, a neoplastic transformation inhibitor, the tumorigenic reprogramming of pASCs was associated with trafficking by PC cell-derived exosomes of oncogenic factors, including H-ras and K-ras transcripts, oncomiRNAs miR-125b, miR-130b, and miR-155 as well as the Ras superfamily of GTPases Rab1a, Rab1b, and Rab11a. Our findings implicate a new role for PC cell-derived exosomes in clonal expansion of tumors through neoplastic reprogramming of tumor tropic ASCs in cancer patients.

Doxorubicin resistance in breast cancer is driven by light at night-induced disruption of the circadian melatonin signal.

Chemotherapeutic resistance, particularly to doxorubicin (Dox), represents a major impediment to successfully treating breast cancer and is linked to elevated tumor metabolism and tumor over-expression and/or activation of various families of receptor- and non-receptor-associated tyrosine kinases. Disruption of circadian time structure and suppression of nocturnal melatonin production by dim light exposure at night (dLEN), as occurs with shift work, and/or disturbed sleep-wake cycles, is associated with a significantly increased risk of an array of diseases, including breast cancer. Melatonin inhibits human breast cancer growth via mechanisms that include the suppression of tumor metabolism and inhibition of expression or phospho-activation of the receptor kinases AKT and ERK1/2 and various other kinases and transcription factors. We demonstrate in tissue-isolated estrogen receptor alpha-positive (ERα+) MCF-7 human breast cancer xenografts, grown in nude rats maintained on a light/dark cycle of LD 12:12 in which dLEN is present during the dark phase (suppressed endogenous nocturnal melatonin), a significant shortening of tumor latency-to-onset, increased tumor metabolism and growth, and complete intrinsic resistance to Dox therapy. Conversely, a LD 12:12 dLEN environment incorporating nocturnal melatonin replacement resulted in significantly lengthened tumor latency-to-onset, tumor regression, suppression of nighttime tumor metabolism, and kinase and transcription factor phosphorylation, while Dox sensitivity was completely restored. Melatonin acts as both a tumor metabolic inhibitor and circadian-regulated kinase inhibitor to reestablish the sensitivity of breast tumors to Dox and drive tumor regression, indicating that dLEN-induced circadian disruption of nocturnal melatonin production contributes to a complete loss of tumor sensitivity to Dox chemotherapy.

In vivo anticancer synergy mechanism of doxorubicin and verapamil combination treatment is impaired in BALB/c mice with metastatic breast cancer.

The development of resistance to anticancer drugs is a major unsolved problem in the chemotherapy treatment of metastatic breast cancer. We have shown that increased expression of P-glycoprotein (P-gp) prevented nuclear entry of the doxorubicin molecules into murine breast cancer cells (4T1-R) leading to doxorubicin chemoresistance. This study was performed to test whether inhibition of P-gp using verapamil could overcome doxorubicin chemoresistance and eliminate multiorgan metastasis 4T1-R cells in BALB/c mouse. The 4T1-R cells were treated with doxorubicin alone, verapamil alone, and a combination of both. Multiorgan metastasis of 4T1-R cells in the presence and in the absence of combination treatment was determined in the BALB/c mouse model. Verapamil induced nuclear translocation of doxorubicin, G2-phase growth arrest and synergistically induced 100% cytotoxicity in 4T1-R cells in culture. However, the combination treatment using verapamil and doxorubicin did not improve the overall survival of BALB/c mice with metastatic breast cancer. Our results indicate that the combination treatment of verapamil and doxorubicin did not inhibit tumor growth in the lungs and liver indicating that the anticancer synergy mechanism of verapamil and doxorubicin is impaired in vivo in BALB/c mouse model with metastatic breast cancer. We propose that understanding the mechanisms as to why the combination of doxorubicin and verapamil treatment was impaired in the mouse model should allow novel approaches to improve chemotherapy response of metastatic breast cancer.

Granulomatous amoebic encephalitis due to Acanthamoeba spp complicating multidrug-resistant tuberculous meningitis in an immunocompetent individual.

Granulomatous amoebic encephalitis due to Acanthamoeba spp is a rare, near-fatal central nervous system infection. It is often seen in immunocompromised individuals. Here we describe a survivor of this infection who was co-infected with multidrug-resistant tuberculosis. He presented to us with features of meningitis and a history of chronic cough. The chest X-ray was classical for pulmonary tuberculosis. Neuroimaging was suggestive of encephalitis; herpes simplex virus PCR was negative. Cerebrospinal fluid (CSF) showed lymphocytic pleocytosis. Wet mounts revealed trophozoites of Acanthamoeba Currently, he is being treated with oral bedaquiline, levofloxacin, linezolid, clofazimine, cycloserine and pyridoxine for tuberculosis. He received intravenous amikacin and oral cotrimoxazole and fluconazole for Acanthamoeba infection for 1 month. The resolution was confirmed by repeating the CSF wet mount, culture and neuroimaging. He was then discharged with oral rifampicin, cotrimoxazole and fluconazole. He is currently under our close follow-up.

Cycloviolacin O2 (CyO2) suppresses productive infection and augments the antiviral efficacy of nelfinavir in HIV-1 infected monocytic cells.

Human immunodeficiency virus type-1 (HIV-1), the etiologic agent of acquired immune deficiency syndrome (AIDS), is a global pandemic causing millions of deaths annually. Highly active antiretroviral therapy (HAART) greatly enhances lifespan but eventually causes debilitating side effects, in part, due to their chronic administration required to suppress HIV-1 replication. If treatment is discontinued, viral suppression is lost and dormant replication-competent monocytic cell reservoirs become reactivated, leading to viral recrudescence and progression to AIDS. Therefore, novel strategies to circumvent obstacles to HIV-1 therapy are critically needed. We evaluated the potentially therapeutic effects of cycloviolacin O2 (CyO2) on cell viability (MTT assay), membrane disruption (SYTOX Green uptake), p24 production [enzyme-linked immunosorbent assays (ELISA)], and proviral integration (PCR amplification) in U1 cells; a monocytic cell model of HIV-1 latency and reactivation. We demonstrate, for the first time, that CyO2 (0.5-5.0 µM) kills productively infected cells. Sub-toxic concentrations (<0.5 µM) of CyO2 disrupted plasma membranes in both latently-infected and productively-infected U1 cells and enhanced the antiviral efficacy of nelfinavir, a HIV-1 protease inhibitor (HPI). Interestingly, CyO2 also decreased virus production by activated U1 cells; however, this effect was not due to suppression of integrated provirus in U1 cells. This suggested that, in addition to the known pore-forming ability of cyclotides, a novel mode of antiviral activity may exist for CyO2. Our data indicate that CyO2 may be a promising candidate for the targeting HIV-1 reservoirs in monocytes, and their inclusion in adjuvant therapy approaches may augment the efficacy of HPIs and ultimately facilitate virus elimination.

A systematic approach to document cyclotide distribution in plant species from genomic, transcriptomic, and peptidomic analysis.

Cyclotides are a large family of plant peptides characterized by their cyclic cystine knot composed of a circular backbone and three disulfide bonds that impart exceptional stability. They, and several acyclic variants, have been isolated from plants within the Rubiaceae, Violaceae, Cucurbitaceae, Fabaceae, Solanaceae, and Poaceae families. A variety of chemical and genetic approaches have been applied for the discovery and characterization of cyclotides. As investigations of cyclotide expression, distribution, and phylogeny rapidly increase, the authors have proposed the inclusion of information pertaining to plant species that have been analyzed but do not appear to express cyclotides into the CyBase database. CyBase is dedicated to providing web tools and information about cyclic peptides and proteins to the scientific community. Including detailed information about sampling and analysis parameters of plant species that have been investigated but not published elsewhere should assist in the process of selecting species for establishing new cyclotide discovery projects, as well as for detailed reanalysis using alternative technical approaches. In summary, the collection and deposition of all plant species that have been examined (whether cyclotides have been found or not) would help to impart a deeper understanding of cyclotide discovery, evolution, and physiological function.

Synergistic inhibition of thyroid cancer by suppressing MAPK/PI3K/AKT pathways.

BACKGROUND: Although a wide spectrum of inhibitors of the MEK/ERK and PI3K/AKT pathways have been discovered and entered clinical trials, the effects of their individual use in thyroid cancer were often disappointing. We hypothesized that dual targeting of these two pathways would be a safe and effective strategy against aggressive thyroid cancers. METHODS: We examined the antiproliferative effects of the MEK/ERK inhibitor AZD6244 and the PI3K/AKT inhibitor GDC0941, individually or in combination, on thyroid cancer cells harboring both the BRAF(V600E) and PIK3CA mutations. The effects of drug exposure on both total and phosphorylated (p-) forms of AKT and ERK were monitored by Western blotting analysis. Effects of these inhibitors on cell-cycle progression and apoptosis were measured by flow cytometry and DNA-fragmentation analyses, respectively. RESULTS: We observed significant toxicities to viability of cells with low concentrations of AZD6244 or GDC0941, which were synergistic when the two inhibitors were used in combination (P < 0.01). AZD6244 abrogated p-ERK and GDC0941 abrogated p-AKT levels, confirming their expected target effects. Unexpectedly, monotherapy with AZD6244 resulted in activation of the PI3K signaling pathway in some cancer cell lines and co-exposure to AZD6244 and GDC0941 was necessary to suppress both pathways. Flow cytometry showed G1 arrest. DNA fragmentation analysis showed an increased apoptosis of cells dually treated with the two inhibitors. CONCLUSION: Concomitant suppression of MEK/ERK and PI3K/AKT pathways by AZD6244 and GDC0941 abrogates compensatory mechanisms of tumor survival and causes synergistic cytotoxicity in thyroid cancer cells.

Attenuation of low dose methylmercury and glutamate induced-cytotoxicity and tau phosphorylation by an N-methyl-D-aspartate antagonist in human neuroblastoma (SHSY5Y) cells.

Methylmercury (MeHg), a known neurotoxin, has been reported to alter glutamate homeostasis in the neuronal environment resulting in excitotoxicity. This study was conducted to investigate whether, and if so, under what conditions, that low dose MeHg would enhance the toxicity of glutamate and to what extent that blockade of NMDA receptors would alter MeHg and glutamate's toxicity in cultured neuroblastoma cells. Neuroblastoma cells (SH-SY5Y) were used in a cell culture model to study effects of MeHg, glutamate (glu), a calcium chelator (BAPTA-AM), and a noncompetitive NMDA antagonist, MK-801 on cell growth, cell survival, and phosphorylation of tau protein, as a measure of cellular events associated with tauopathies. Exposure of cells to a combination of MeHg (50 nM) and glutamate (1 mM) resulted in both a greater decrease in cell viability as well as a greater induction in tau phosphorylation, as compared to exposures with MeHg and glutamate alone. MK-801, an NMDA receptor antagonist, and the intracellular calcium chelator, BAPTA-AM, both significantly inhibited tau hyperphosphorylation and protected cells from the effects of combination exposures to glutamate and MeHg. These results may indicate that exposure to even nontoxic levels of MeHg may prime neuronal cells to be more susceptible to neuronal injury from excitotoxicants such as glutamate and thus may increase the likelihood of neurological disease states. In conclusion, low-dose MeHg-induced toxicity may be related to an increase in the cellular response to glutamate and that NMDA receptor antagonists may provide a potential treatment for MeHg-associated neurological diseases.

Physician stress in the era of COVID-19 vaccine disparity: a multi-institutional survey.

CONTEXT: Healthcare workers are at a high risk of infection during infectious disease outbreaks, such as the COVID-19 pandemic. Despite the availability of several vaccines against COVID-19, the absence of vaccination in patients and colleagues remains a continuous source of stress in healthcare workers. We conducted a survey of physician preceptors, both MDs and DOs, to explore the impact of differences in the patients' and colleagues' vaccination status on their well-being, stress, and burnout. OBJECTIVES: The objective of this study is to determine whether exposure to unvaccinated patients and/or colleagues increases stress and burnout in physician preceptors by utilizing a self-reported survey. METHODS: This multi-institutional study was carried out in the United States in 2022. An online survey questionnaire was utilized to collect data from physicians working as preceptors for multiple academic institutions. The anonymous Qualtrics® survey utilized a modified version of the questionnaire from the expanded Physician Well-being Index (ePWBI) designed by MedEd Web Solutions (MEWS). Statistical analysis on both descriptive and qualitative data were performed. Utilizing a threshold of p≤0.05, data analysis revealed many statistically significant relationships between the variables. RESULTS: A total of 218 physician preceptors completed the survey. The survey results showed that physicians overwhelmingly (p < 0.001) felt that all patients (and healthcare workers) should be vaccinated. The results also indicated that physicians experienced more stress when working with unvaccinated patients (p<0.001), and these stressors were often associated with the physician's gender and age. Furthermore, physicians stated that both their assessment and treatment plans were significantly different for vaccinated vs unvaccinated patients (p=0.039 and p=0.0167, respectively). Most importantly, stress levels (p<0.001) and burnout characteristics (p=0.024) were noted by physicians, both in themselves and in their colleagues. CONCLUSIONS: Findings suggest that physician stress and burnout is a common theme due to the differences in vaccination status of patients admitted to COVID-19 clinics. Due to a more rapid progression of COVID-19 in unvaccinated patients, treatment plans for vaccinated vs unvaccinated patients were also considerably different.

Low-dose methylmercury-induced oxidative stress, cytotoxicity, and tau-hyperphosphorylation in human neuroblastoma (SH-SY5Y) cells.

Acute neurotoxic effects of high-dose methylmercury (MeHg) in humans have been well documented in the scientific literature. However, low-dose effects are less well described. This study was designed to evaluate the effects of low-dose MeHg (<100 nM) on human brain cells in a tissue culture model. Neuroblastoma (NB) cells (SH-SY5Y) were used in the cell culture model to study low-dose effects of MeHg on cell growth, cell survival, reactive oxygen species (ROS), and the phosphorylation of tau protein, as a measure of potential markers of cellular events associated with tauopathies. When cells were incubated in culture with MeHg (50 and 100 nM), there were significant decreases in cell viability as well as significant increase in ROS generation as determined by fluorescent dye analysis (H(2)DCFDA). Furthermore, a concomitant decrease in glutathione levels to 25% of control was observed at both 50 and 100 nM MeHg. In addition, the level of phosphorylated tau was significantly increased after treatment at both 50 and 100 nM MeHg, compared with controls. Pretreatment of NB cells with the antioxidant, N-acetylcysteine (1.25 mM) and the calpain inhibitor, MDL-28170 (10 µM), significantly attenuated the effects of MeHg (50 and 100 nM) on cell viability as well as on tau phosphorylation. These results indicate that low-dose MeHg toxicity may be related to an induction of tau phosphorylation through an oxidative stress-dependent mechanism and that blockade of this pathway may attenuate the toxic effects of MeHg.

Osteopathic Manipulative Medicine: A Brief Review of the Hands-On Treatment Approaches and Their Therapeutic Uses.

Osteopathic manipulative medicine (OMM) is an emerging practice in the healthcare field with increasing popularity and evidence-based therapy. Osteopathic manipulative treatments (OMT) include hands-on manipulations of different body structures to increase systemic homeostasis and total patient well-being. Indeed, this new realm of the whole patient-based approach is being taught in osteopathic schools around the country, and the osteopathic principles of a mind-body-spirit-based treatment are being instilled in many new Doctor of Osteopathy (D.O.) students. However, despite their proven therapeutic value, there are still many individuals, both in and outside the medical profession, who are unaware (or misinformed) of the therapeutic uses and potential benefits of OMT. Here, we provide a brief introduction to this osteopathic therapeutic approach, focusing on the hands-on techniques that are regularly implemented in the clinical setting. It is becoming increasingly evident that different OMTs can be implemented to enhance patient recovery, both alone and in conjunction with the targeted therapies used in allopathic regimens. Therefore, it may be beneficial to inform the general medical community and educate the public and those associated with the healthcare field about the benefits of using OMT as a treatment modality. OMT is lower-cost, noninvasive, and highly effective in promoting full-body healing by targeting the nervous, lymphatic, immune, and vascular systems. There is a growing body of literature related to osteopathic research and the possible molecular pathways involved in the healing process, and this burgeoning field of medicine is expected to increase in value in the healthcare field. This brief review article explains the frequently utilized OMT modalities and their recognized therapeutic benefits, which underscore the need to understand the possible molecular mechanisms and circulating biomarkers linked to the systemic benefits of osteopathic medicine.

Osteopathic Manipulative Treatment Decreases Hospital Stay and Healthcare Cost in the Neonatal Intensive Care Unit.

Osteopathic manipulative treatment (OMT) is used in both inpatient and outpatient settings. Evidence suggests that OMT can reduce both patients' recovery time and the financial cost of their acute medical treatment and rehabilitation. Multiple studies from neonatal intensive care units (NICUs) are presented in this article that demonstrate infants treated with OMT recover faster, are discharged earlier, and have lower healthcare costs than their non-OMT-treated counterparts. Data clearly show that adjunctive OMT facilitates feeding coordination in newborns, such as latching, suckling, swallowing, and breathing, and increases long-term weight gain and maintenance, which reduces hospital length of stay (LOS). Osteopathic techniques, such as soft tissue manipulation, balanced ligamentous tension, myofascial release, and osteopathic cranial manipulation (OCM), can reduce regurgitation, vomiting, milky bilious, or bloody discharge and decrease the need for constipation treatment. OMT can also be effective in reducing the complications of pneumonia in premature babies. Studies show the use of OCM and lymphatic pump technique (LPT) reduces the occurrence of both aspiration and environmentally acquired pneumonia, resulting in significantly lower morbidity and mortality in infants. Based on published findings, it is determined that OMT is clinically effective, cost efficient, a less invasive alternative to surgery, and a less toxic choice to pharmacologic drugs. Therefore, routine incorporation of OMT in the NICU can be of great benefit in infants with multiple disorders. Future OMT research should aim to initiate clinical trial designs that include randomized controlled trials with larger cohorts of infants admitted to the NICU. Furthermore, a streamlined and concerted effort to elucidate the underlying molecular mechanisms associated with the beneficial effects of OMT will aid in understanding the significant value of incorporating OMT into optimal patient care.

Pre-Exposure to Stress-Inducing Agents Increase the Anticancer Efficacy of Focused Ultrasound against Aggressive Prostate Cancer Cells.

Despite the initial success in treatment of localized prostate cancer (PCa) using surgery, radiation or hormonal therapy, recurrence of aggressive tumors dictates morbidity and mortality. Focused ultrasound (FUS) is being tested as a targeted, noninvasive approach to eliminate the localized PCa foci, and strategies to enhance the anticancer potential of FUS have a high translational value. Since aggressive cancer cells utilize oxidative stress (Ox-stress) and endoplasmic reticulum stress (ER-stress) pathways for their survival and recurrence, we hypothesized that pre-treatment with drugs that disrupt stress-signaling pathways in tumor cells may increase FUS efficacy. Using four different PCa cell lines, i.e., LNCaP, C4-2B, 22Rv1 and DU145, we tested the in vitro effects of FUS, alone and in combination with two clinically tested drugs that increase Ox-stress (i.e., CDDO-me) or ER-stress (i.e., nelfinavir). As compared to standalone FUS, significant (p < 0.05) suppressions in both survival and recurrence of PCa cells were observed following pre-sensitization with low-dose CDDO-me (100 nM) and/or nelfinavir (2 µM). In drug pre-sensitized cells, significant anticancer effects were evident at a FUS intensity of as low as 0.7 kW/cm2. This combined mechanochemical disruption (MCD) approach decreased cell proliferation, migration and clonogenic ability and increased apoptosis/necrosis and reactive oxygen species (ROS) production. Furthermore, although activated in cells that survived standalone FUS, pre-sensitization with CDDO-me and/or nelfinavir suppressed both total and activated (phosphorylated) NF-κB and Akt protein levels. Thus, a combined MCD therapy may be a safe and effective approach towards the targeted elimination of aggressive PCa cells.

Mesenchymal stem cell derived hematopoietic cells are permissive to HIV-1 infection.

BACKGROUND: Tissue resident mesenchymal stem cells (MSCs) are multipotent, self-renewing cells known for their differentiation potential into cells of mesenchymal lineage. The ability of single cell clones isolated from adipose tissue resident MSCs (ASCs) to differentiate into cells of hematopoietic lineage has been previously demonstrated. In the present study, we investigated if the hematopoietic differentiated (HD) cells derived from ASCs could productively be infected with HIV-1. RESULTS: HD cells were generated by differentiating clonally expanded cultures of adherent subsets of ASCs (CD90+, CD105+, CD45-, and CD34-). Transcriptome analysis revealed that HD cells acquire a number of elements that increase their susceptibility for HIV-1 infection, including HIV-1 receptor/co-receptor and other key cellular cofactors. HIV-1 infected HD cells (HD-HIV) showed elevated p24 protein and gag and tat gene expression, implying a high and productive infection. HD-HIV cells showed decreased CD4, but significant increase in the expression of CCR5, CXCR4, Nef-associated factor HCK, and Vpu-associated factor BTRC. HIV-1 restricting factors like APOBEC3F and TRIM5 also showed up regulation. HIV-1 infection increased apoptosis and cell cycle regulatory genes in HD cells. Although undifferentiated ASCs failed to show productive infection, HIV-1 exposure increased the expression of several hematopoietic lineage associated genes such as c-Kit, MMD2, and IL-10. CONCLUSIONS: Considering the presence of profuse amounts of ASCs in different tissues, these findings suggest the possible role that could be played by HD cells derived from ASCs in HIV-1 infection. The undifferentiated ASCs were non-permissive to HIV-1 infection; however, HIV-1 exposure increased the expression of some hematopoietic lineage related genes. The findings relate the importance of ASCs in HIV-1 research and facilitate the understanding of the disease process and management strategies.

Oxidative stress and redox signaling in CRPC progression: therapeutic potential of clinically-tested Nrf2-activators.

Androgen deprivation therapy (ADT) is the mainstay regimen in patients with androgen-dependent prostate cancer (PCa). However, the selection of androgen-independent cancer cells leads to castrate resistant prostate cancer (CRPC). The aggressive phenotype of CRPC cells underscores the need to elucidate mechanisms and therapeutic strategies to suppress CRPC outgrowth. Despite ADT, the activation of androgen receptor (AR) transcription factor continues via crosstalk with parallel signaling pathways. Understanding of how these signaling cascades are initiated and amplified post-ADT is lacking. Hormone deprivation can increase oxidative stress and the resultant reactive oxygen species (ROS) may activate both AR and non-AR signaling. Moreover, ROS-induced inflammatory cytokines may further amplify these redox signaling pathways to augment AR function. However, clinical trials using ROS quenching small molecule antioxidants have not suppressed CRPC progression, suggesting that more potent and persistent suppression of redox signaling in CRPC cells will be needed. The transcription factor Nrf2 increases the expression of numerous antioxidant enzymes and downregulates the function of inflammatory transcription factors, e.g., nuclear factor kappa B. We documented that Nrf2 overexpression can suppress AR-mediated transcription in CRPC cell lines. Furthermore, two Nrf2 activating agents, sulforaphane (a phytochemical) and bardoxolone-methyl (a drug in clinical trial) suppress AR levels and sensitize CRPC cells to anti-androgens. These observations implicate the benefits of potent Nrf2-activators to suppress the lethal signaling cascades that lead to CRPC outgrowth. This review article will address the redox signaling networks that augment AR signaling during PCa progression to CRPC, and the possible utility of Nrf2-activating agents as an adjunct to ADT.

Latent HIV-Exosomes Induce Mitochondrial Hyperfusion Due to Loss of Phosphorylated Dynamin-Related Protein 1 in Brain Endothelium.

Damage to the cerebral vascular endothelium is a critical initiating event in the development of HIV-1-associated neurocognitive disorders. To study the role of mitochondria in cerebral endothelial dysfunction, we investigated how exosomes, isolated from both cell lines with integrated provirus and HIV-1 infected primary cells (HIV-exosomes), accelerate the dysfunction of primary human brain microvascular endothelial cells (HBMVECs) by inducing mitochondrial hyperfusion, and reducing the expression of phosphorylated endothelial nitric oxide synthase (p-eNOS). The quantitative analysis of the extracellular vesicles (EVs) indicates that the isolated EVs were predominantly exosomes. It was further supported by the detection of exosomal markers, and the absence of large EV-related protein in the isolated EVs. The exosomes were readily taken up by primary HBMVECs. HIV-exosomes induce cellular and mitochondrial superoxide production but reduce mitochondrial membrane potential in HBMVECs. HIV-exosomes increase mitochondrial hyperfusion, possibly due to loss of phosphorylated dynamin-related protein 1 (p-DRP1). HIV-exosomes, containing the HIV-Tat protein, and viral Tat protein reduce the expression of p-DRP1 and p-eNOS, and accelerate brain endothelial dysfunction. Finally, exosomes isolated from HIV-1 infected primary human peripheral blood mononuclear cells (hPBMCs) produce more exosomes than uninfected controls and reduce both p-DRP1 and p-eNOS expressions in primary HBMVECs. Our novel findings reveal the significant role of HIV-exosomes on dysregulation of mitochondrial function, which induces adverse changes in the function of the brain microvascular endothelium.

Isolation, characterization, and bioactivity of cyclotides from the Micronesian plant Psychotria leptothyrsa.

Cyclotides, the largest known family of head-to-tail cyclic peptides, have approximately 30 amino acid residues with a complex structure containing a circular peptide backbone and a cystine knot. They are found in plants from the Violaceae and Rubiaceae families and are speculated to function in plant protection. In addition to their insecticidal properties, cyclotides display cytotoxic, anti-HIV, antimicrobial, and inhibition of neurotensin binding activities. Although cyclotides are present in all violaceous species hitherto screened, their distribution and expression in Rubiaceae are not fully understood. In this study, we show that Psychotria leptothyrsa var. longicarpa (Rubiaceae) contains a suite of different cyclotides. The cyclotide fractions were isolated by RP-HPLC, and sequences of six new peptides, named psyles A-F, were determined by MS/MS sequencing. One of these, psyle C, is the first rubiaceous linear variant known. Psyles A, C, and E were analyzed in a fluorometric microculture assay to determine cytotoxicity toward the human lymphoma cell line U937-GTB. The IC(50) values of psyles A, C, and E were 26, 3.50, and 0.76 muM, respectively. This study expands the number of known rubiaceous cyclotides and shows that the linear cyclotide maintains cytotoxicity.

Bardoxolone-Methyl (CDDO-Me) Suppresses Androgen Receptor and Its Splice-Variant AR-V7 and Enhances Efficacy of Enzalutamide in Prostate Cancer Cells.

Androgen receptor (AR) signaling is fundamental to prostate cancer (PC) progression, and hence, androgen deprivation therapy (ADT) remains a mainstay of treatment. However, augmented AR signaling via both full length AR (AR-FL) and constitutively active AR splice variants, especially AR-V7, is associated with the recurrence of castration resistant prostate cancer (CRPC). Oxidative stress also plays a crucial role in anti-androgen resistance and CRPC outgrowth. We examined whether a triterpenoid antioxidant drug, Bardoxolone-methyl, known as CDDO-Me or RTA 402, can decrease AR-FL and AR-V7 expression in PC cells. Nanomolar (nM) concentrations of CDDO-Me rapidly downregulated AR-FL in LNCaP and C4-2B cells, and both AR-FL and AR-V7 in CWR22Rv1 (22Rv1) cells. The AR-suppressive effect of CDDO-Me was evident at both the mRNA and protein levels. Mechanistically, acute exposure (2 h) to CDDO-Me increased and long-term exposure (24 h) decreased reactive oxygen species (ROS) levels in cells. This was concomitant with an increase in the anti-oxidant transcription factor, Nrf2. The anti-oxidant N-acetyl cysteine (NAC) could overcome this AR-suppressive effect of CDDO-Me. Co-exposure of PC cells to CDDO-Me enhanced the efficacy of a clinically approved anti-androgen, enzalutamide (ENZ), as evident by decreased cell-viability along with migration and colony forming ability of PC cells. Thus, CDDO-Me which is in several late-stage clinical trials, may be used as an adjunct to ADT in PC patients.

HIV-1 protease inhibitor induced oxidative stress suppresses glucose stimulated insulin release: protection with thymoquinone.

The highly active anti-retroviral therapy (HAART) regimen has considerably reduced the mortality rate in HIV-1 positive patients. However, long-term exposure to HAART is associated with a metabolic syndrome manifesting cardiovascular dysfunction, lipodystrophy, and insulin resistance syndrome (IRS). The inclusion of HIV-1 protease inhibitors (PIs) in HAART has been linked to the induction of IRS. Although several molecular mechanisms of PI-induced effects on insulin action have been postulated, the deleterious effects of PIs on insulin production by pancreatic beta-cells have not been fully investigated and therapeutic strategies to ameliorate insulin dysregulation at this level have not been targeted. The present study showed that exposure to several different PIs, nelfinavir (5-10 microM), saquinavir (5-10 microM) and atazanavir (8-20 microM), decreases glucose stimulated insulin secretion from rat pancreatic beta-cells (INS-1). Nelfinavir significantly increased reactive oxygen species (ROS) generation and suppressed cytosolic, but not mitochondrial superoxide dismutase (SOD) levels. Nelfinvair also decreased both glutathione and ATP and increased UCP2 levels in these cells. Simultaneous treatment with thymoquinone (TQ) (2.5 microM), an active ingredient of black seed oil, significantly inhibited the effect of nelfinavir on augmented ROS production and suppressed SOD levels. Both TQ and black seed oil exposure increased glucose stimulated insulin secretion and ameliorated the suppressive effect of nelfinavir. The present findings imply a direct role of ROS in PI induced deleterious effects on pancreatic beta-cells. Our findings also suggest that TQ may be used as a potential therapeutic agent to normalize the dysregulated insulin production observed in HAART treated patients.