Elimination of HIV-1 infection by treatment with a doxorubicin-conjugated anti-envelope antibody

Drug repurposing approach against chikungunya virus: an in vitro and in silico study

The chikungunya virus (CHIKV) is an alphavirus transmitted by Aedes mosquitoes. There are no licenced antivirals or vaccines for treatment or prevention. Drug repurposing approach has emerged as a novel concept to find alternative uses of therapeutics to battle pathogens. In the present study, anti CHIKV activity of fourteen FDA-approved drugs was investigated by in vitro and in silico approaches. Focus-forming unit assay, immunofluorescence test, and quantitative RT-PCR assay were used to assess the in vitro inhibitory effect of these drugs against CHIKV in Vero CCL-81 cells. The findings showed that nine compounds, viz., temsirolimus, 2-fluoroadenine, doxorubicin, felbinac, emetine, lomibuvir, enalaprilat, metyrapone and resveratrol exhibit anti chikungunya activity. Furthermore, in silico molecular docking studies performed by targeting CHIKV structural and non-structural proteins revealed that these drugs can bind to structural protein targets such as envelope protein, and capsid, and non-structural proteins NSP2, NSP3 and NSP4 (RdRp). Findings from in vitro and in silico studies reveal that these drugs can suppress the infection and replication of CHIKV and further in vivo studies followed by clinical trials are warranted.

Antibody Conjugates for Targeted Therapy Against HIV-1 as an Emerging Tool for HIV-1 Cure

Although advances in antiretroviral therapy (ART) have significantly improved the life expectancy of people living with HIV-1 (PLWH) by suppressing HIV-1 replication, a cure for HIV/AIDS remains elusive. Recent findings of the emergence of drug resistance against various ART have resulted in an increased number of treatment failures, thus the development of novel strategies for HIV-1 cure is of immediate need. Antibody-based therapy is a well-established tool in the treatment of various diseases and the engineering of new antibody derivatives is expanding the realms of its application. An antibody-based carrier of anti-HIV-1 molecules, or antibody conjugates (ACs), could address the limitations of current HIV-1 ART by decreasing possible off-target effects, reduce toxicity, increasing the therapeutic index, and lowering production costs. Broadly neutralizing antibodies (bNAbs) with exceptional breadth and potency against HIV-1 are currently being explored to prevent or treat HIV-1 infection in the clinic. Moreover, bNAbs can be engineered to deliver cytotoxic or immune regulating molecules as ACs, further increasing its therapeutic potential for HIV-1 cure. ACs are currently an important component of anticancer treatment with several FDA-approved constructs, however, to date, no ACs are approved to treat viral infections. This review aims to outline the development of AC for HIV-1 cure, examine the variety of carriers and payloads used, and discuss the potential of ACs in the current HIV-1 cure landscape.

Assessment of the Blood Parameters, Cardiac and Liver Enzymes in Oral Squamous Cell Carcinoma Following Treated with Injectable Doxorubicin-Loaded Nano-Particles

Purpose:

Oral squamous cell carcinoma (OSCC) is the most common and most malignant disorder of the oral cavity. Standard cancer treatments have many complications for patients. Nausea, vomiting, and perturbation in blood cells are the most common side effects when using Doxorubicin (Dox) for the treatment of OSCC. Use of Doxorubicin-loaded nano-particles (n-Dox) give rise to increase its biological efficacy and the rapeutic effects. This study assessed the efficacy of the injectable form of the n-Doxon blood parameters and cardiac and liver enzymes compared to the commercial form of Dox in OSCC-induced by 4NQO in rats.

Methods:

4-nitroquinoline-1-oxideas was used as a solution in drinking water for inducing OSCC during 14 weeks in male Sprague-Dawley rats. Four groups of animals were categorized randomly: first (OSCC+Dox), second (OSCC+n-Dox), third (OSCC) and, last, healthy animals.

Results:

Using n-Dox had no harmful effect on the number of white and red blood cells. Thrombocytopenia and leukopenia in animals treated with n-Dox was less than the other groups. Hemoglobin and hematocrit in all treated groups did not differ and were similar to the healthy control. Hepatic and cardiac enzymes did not show any significant difference in any of the groups.

Conclusion:

The results of this research showed that significant decreases in haematological changes occurred, including leukopenia and anemia, in an animal model of OSCC induced by 4-NQO following use of n-Dox with compare to Dox. Use of n-Dox is better than of Dox for treatment of OSCC.

Specific Elimination of Latently HIV-1 Infected Cells Using HIV-1 Protease-Sensitive Toxin Nanocapsules

Anti-retroviral drugs suppress HIV-1 plasma viremia to undetectable levels; however, latent HIV-1 persists in reservoirs within HIV-1-infected patients. The silent provirus can be activated through the use of drugs, including protein kinase C activators and histone deacetylase inhibitors. This “shock” approach is then followed by “kill” of the producing cells either through direct HIV-1-induced cell death or natural immune mechanisms. However, these mechanisms are relatively slow and effectiveness is unclear. Here, we develop an approach to specifically target and kill cells that are activated early in the process of virus production. We utilize a novel nanocapsule technology whereby the ricin A chain is encapsulated in an inactive form within a polymer shell. Specificity for release of the ricin A toxin is conferred by peptide crosslinkers that are sensitive to cleavage by HIV-1 protease. By using well-established latent infection models, J-Lat and U1 cells, we demonstrate that only within an HIV-1-producing cell expressing functional HIV-1 protease will the nanocapsule release its ricin A cargo, shutting down viral and cellular protein synthesis, and ultimately leading to rapid death of the producer cell. Thus, we provide proof of principle for a novel technology to kill HIV-1-producing cells without effects on non-target cells.

Curing HIV: lessons from cancer therapy

PURPOSE OF REVIEW

Interest in finding a potential 'cure' for HIV has taken on greater interest and urgency since the report of an individual who underwent allogeneic stem cell transplant from a CCR5 delta 32 homozygote donor after high-dose chemotherapy for acute myeloid leukemia. The potential role of cancer chemotherapy and other cancer-directed treatment approaches is discussed in the context of their potential role in helping to eliminate HIV from the infected host.

RECENT FINDINGS

Cancer chemotherapy and other cancer-targeted agents have been used successfully in treating a variety of malignancies in both HIV-infected and HIV-uninfected individuals. Lessons learned from these strategies may be of importance in helping to define more effective ways of controlling and eliminating HIV as well. Application of these anticancer strategies to patients with HIV are beginning to be explored and may help determine their potential usefulness in this disease as well.

SUMMARY

Although cytotoxic chemotherapy is a crude and not particularly effective way of removing HIV latently infected cells and tissue reservoirs, several new approaches to targeting and controlling cancer proliferation may be of value in HIV cure research and may one day help to end this disease.

ADAM17-overexpressing breast cancer cells selectively targeted by antibody-toxin conjugates

A disintegrin and metalloproteinase 17 (ADAM17) is significantly upregulated not only in malignant cells but also in the pro-inflammatory microenvironment of breast cancer. There, ADAM17 is critically involved in the processing of tumor-promoting proteins. Therefore, ADAM17 appears to be an attractive therapeutic target to address not only tumor cells but also the tumor-promoting environment. In a previous study, we generated a monoclonal anti-ADAM17 antibody (A300E). Although showing no complement-dependent cytotoxicity or antibody-dependent cellular cytotoxicity, the antibody was rapidly internalized by ADAM17-expressing cells and was able to transport a conjugated toxin into target cells. As a result, doxorubicin-coupled A300E or Pseudomonas exotoxin A-loaded A300E was able to kill ADAM17-expressing cells. This effect was strictly dependent on the presence of ADAM17 on the surface of target cells. As a proof of principle, both immunotoxins killed MDA-MB-231 breast cancer cells in an ADAM17-dependent manner. These data suggest that the use of anti-ADAM17 monoclonal antibodies as a carrier might be a promising new strategy for selective anti-cancer drug delivery.

A novel class of anti-HIV agents with multiple copies of enfuvirtide enhances inhibition of viral replication and cellular transmission in vitro

We constructed novel HIV-1 fusion inhibitors that may overcome the current limitations of enfuvirtide, the first such therapeutic in this class. The three prototypes generated by the Dock-and-Lock (DNL) technology to comprise four copies of enfuvirtide tethered site-specifically to the Fc end of different humanized monoclonal antibodies potently neutralize primary isolates (both R5-tropic and X4-tropic), as well as T-cell-adapted strains of HIV-1 in vitro. All three prototypes show EC₅₀ values in the subnanomolar range, which are 10- to 100-fold lower than enfuvirtide and attainable whether or not the constitutive antibody targets HIV-1. The potential of such conjugates to purge latently infected cells was also demonstrated in a cell-to-cell viral inhibition assay by measuring their efficacy to inhibit the spread of HIV-1_LAI from infected human peripheral blood mononuclear cells to Jurkat T cells over a period of 30 days following viral activation with 100 nM SAHA (suberoylanilide hydroxamic acid). The IgG-like half-life was not significantly different from that of the parental antibody, as shown by the mean serum concentration of one prototype in mice at 72 h. These encouraging results provide a rationale to develop further novel anti-HIV agents by coupling additional antibodies of interest with alternative HIV-inhibitors via recombinantly-produced, self-assembling, modules.

A low dose of doxorubicin improves antioxidant defence system and modulates anaerobic metabolism during the development of lymphoma

Objective:

The objective of the present study is to find low dose of doxorubicin (DOX) with cancer preventive activity and to check the implication of this low dose of DOX on antioxidant defence system during lymphoma growth in mice, as the clinical utility of anthracycline anticancer drugs, especially DOX is limited by a progressive cardiotoxicity linked to mitochondrial damage.

Materials and Methods:

We selected a dose of DOX (0.90 mg/kg body weight of mouse), which is about 20 folds lower than clinically used dose for cancer treatment. The cancer preventive action is monitored by modulation of anaerobic metabolism. The effect of this dose on antioxidant defence system is analyzed by testing the activities of antioxidant enzymes, such as catalase (CAT), superoxide dismutase (SOD), and glutathione S-transferase (GST). The activities of these enzymes were monitored at different intervals during the growth of lymphoma in mice.

Results:

The activities of antioxidant enzymes, such as CAT, SOD, and GST, were found to decrease gradually during the growth of lymphoma in mice. The anaerobic metabolism was increasing with lymphoma growth. We report that about 20 folds lower dose of DOX enhances the activities of antioxidant enzymes and decreases anaerobic metabolism during the development of lymphoma. These enzymes of antioxidant defence system suppress oxidative stress and mitochondrial damage, whereas a decrease in anaerobic metabolism checks cancer growth.

Conclusions:

The result suggests that dose cumulative cellular toxicity of DOX may be avoided by treating cancer in animals with lower doses of DOX in combination with other drugs.

Selective killing of Kaposi's sarcoma-associated herpesvirus lytically infected cells with a recombinant immunotoxin targeting the viral gpK8.1A envelope glycoprotein

Kaposi sarcoma-associated herpesvirus (KSHV, human herpesvirus 8) is etiologically associated with three neoplastic syndromes: Kaposi sarcoma and the uncommon HIV-associated B-cell lymphoproliferative disorders primary effusion lymphoma and multicentric Castleman disease. The incidence of the latter B-cell pathology has been increasing in spite of antiretroviral therapy; its association with lytic virus replication has prompted interest in therapeutic strategies aimed at this phase of the virus life cycle. We designed and expressed a recombinant immunotoxin (2014-PE38) targeting the gpK8.1A viral glycoprotein expressed on the surface of the virion and infected cells. We show that this immunotoxin selectively kills KSHV-infected cells in dose-dependent fashion, resulting in major reductions of infectious virus release. The immunotoxin and ganciclovir, an inhibitor of viral DNA replication, showed marked reciprocal potentiation of antiviral activities. These results suggest that the immunotoxin, alone or in combination, may represent a new approach to treat diseases associated with KSHV lytic replication.

Targeted cytotoxic therapy: adapting a rapidly progressing anticancer paradigm for depletion of persistent HIV-infected cell reservoirs

PURPOSE OF REVIEW

HIV-infected cells persisting in the face of highly active antiretroviral therapy are arguably the greatest hurdle to eradication of the virus from the body. Complementary strategies aimed at selective killing of infected cells are described.

RECENT FINDINGS

Pioneered by research in the cancer field, various approaches are under development for selective killing of HIV-infected cells. These include targeted cytotoxic proteins, adoptive cell therapy, cytocidal virotherapy, and targeted nonbiological drug carriers.

SUMMARY

These developmental efforts may provide a critical complement to antiretroviral therapy in efforts to achieve HIV eradication, or a 'functional cure' whereby therapy can be stopped without viral rebound.

A derivate of the antibiotic doxorubicin is a selective inhibitor of dengue and yellow fever virus replication in vitro

A doxorubicin derivate, SA-17, that carries a squaric acid amide ester moiety at the carbohydrate (α-l-daunosaminyl) group was identified as a selective inhibitor of in vitro dengue virus (DENV) serotype 2 replication (50% effective concentration [EC(50)] = 0.34 ± 0.20 μg/ml [0.52 ± 0.31 μM]). SA-17 is markedly less cytostatic than the parent compound, resulting in a selectivity index value of ∼100. SA-17 also inhibits yellow fever virus 17D (YFV-17D) replication (EC(50) = 3.1 ± 1.0 μg/ml [4.8 ± 1.5 μM]), although less efficiently than DENV replication, but proved inactive against a variety of enveloped and nonenveloped viruses. SA-17 inhibits in vitro flavivirus replication in a dose-dependent manner, as was assessed by virus yield reduction assays and quantification of viral RNA by means of real-time quantitative reverse transcriptase PCR (RT-qPCR) (∼2 to 3 log reduction). The anti-DENV activity was confirmed using a Renilla luciferase-expressing dengue reporter virus. Time-of-drug-addition studies revealed that SA-17 acts at the very early stages of the viral replication cycle (i.e., virus attachment and/or virus entry). This observation was corroborated by the observation that SA-17, unlike the nucleoside analogue ribavirin, does not inhibit the replication of DENV subgenomic replicons. Preincubation of high-titer stocks of DENV or YFV-17D with ≥5 μg/ml SA-17 resulted in 100% inhibition of viral infectivity (≥3 log reduction). SA-17, however, did not prove virucidal.

Murine models for HIV vaccination and challenge

HIV-1 only infects humans and chimpanzees. SIV or SHIV are, therefore, used as models for HIV in rhesus, cynomologus and pigtail macaques. Since conducting experiments in primate models does not fully mimic infection or vaccination against HIV-1 and is expensive, there is a great need for small-animal models in which it is possible to study HIV-1 infection, immunity and vaccine efficacy. This review summarizes the available murine models for studying HIV-1 infection with an emphasis on our experience of the HIV-1-infected-cell challenge as a model for evaluating candidate HIV-1 vaccines. In the cell-based challenge model, several important factors that, hopefully, can be related to vaccine efficacy in humans were discovered: the efficiency of combining plasmid DNA representing several of the viral genes originating from multiple clades of HIV-1, the importance of adjuvants activating innate and induced immunity and the enhanced HIV eradication by drug-conjugated antibody.

Antibodies for HIV treatment and prevention: window of opportunity?

Monoclonal antibodies are routinely used as therapeutics in a number of disease settings and have thus also been explored as potential treatment for human immunodeficiency virus (HIV)-1 infection. Antibodies targeting viral antigens, and those directed to the cellular receptors, have been considered for use in prevention and therapy. For virus-targeted antibodies, attention has focused primarily on their neutralizing activity, but such antibodies also have the potential to exert antiviral effects via effector functions, such as antibody-dependent cellular cytotoxicity (ADCC), opsonization, or complement activation. Anti-cell antibodies act through occlusion or down-modulation of the viral receptors with notable impact in vivo, as recent trials have shown. This review summarizes the diverse specificities and modes of action of therapeutic antibodies against HIV-1 infection. Successes, challenges, and future opportunities of harnessing antibodies for therapy of HIV-1 infection are discussed.