Aerobic Exercise Training as a Potential Cardioprotective Strategy to Attenuate Doxorubicin-Induced Cardiotoxicity.

Doxorubicin is one of the most commonly used cytotoxic anticancer drugs against several cancers.  Although a highly effective anticancer drug, the clinical use of doxorubicin is severely limited by its cardiotoxicity which results in morbidity, poor quality of life, and premature mortality.  Only very few clinically accepted methods to minimize doxorubicin-induced cardiac injury are available today, but none of them have proven to be completely successful.  Due to limited alternative strategies, a number of potential cardioprotective therapies are currently being investigated for treating and/or preventing doxorubicin-induced cardiotoxicity.  Of these potential strategies, aerobic exercise training is the only nonpharmacologic strategy that shows a great deal of promise.  Although there are no published human clinical trials, evidence from numerous animal studies suggests that aerobic exercise training, administered prior to, during and/or following doxorubicin therapy, is protective against doxorubicin-induced cardiac injury.  Protective properties of exercise training against the cardiotoxicity of doxorubicin have been attributed to a number of potential molecular mechanisms including:  enhancing the production of endogenous antioxidant machineries; regulating proapoptotic signaling; stimulating the release, mobilization and homing of cardiac progenitor cells; limiting myocyte turnover; eliciting favorable adaptations in myocardial calcium handling and preventing calcium overload; modulating cardiac AMPK activity; downregulating cardiac autophagy/lysosomal signaling; and reducing myocardial doxorubicin accumulation.  Further preclinical and clinical research is needed to decipher and refine the molecular mechanisms underlying the cardioprotective effects of exercise training, as well as to define the nature and magnitude of the effect of exercise on doxorubicin-induced cardiotoxicity in cancer patients. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.

Strategies for Developing Oral Vaccines for Human Papillomavirus (HPV) Induced Cancer using Nanoparticle mediated Delivery System.

Human Papillomaviruses (HPV) are a diverse group of small non-enveloped DNA viruses. Some HPVs are classified as low-risk as they are very rarely associated with neoplasia or cancer in the general population, and cause lenient warts. Other HPVs are considered as high-risk types because they are responsible for several important human cancers, including cervical cancer, a large proportion of other anogenital cancers, and a growing number of head and neck cancers. Transmission of HPV occurs primarily by skin-to-skin contact. The risk of contracting genital HPV infection and cervical cancer is influenced by sexual activity. Currently two prophylactic HPV vaccines, Gardasil® (Merck, USA) and Cervarix® (GlaxoSmithKline, UK), are available and recommended for mass immunization of adolescents. However, these vaccines have limitations as they are expensive and require cold chain storage and trained personnel to administer them by injection. The use of nano or micro particulate vaccines could address most of these limitations as they are stable at room temperature, inexpensive to produce and distribute to resource poor regions, and can be administered orally without the need for adjuvants in the formulation. Also it is possible to increase the efficiency of these particulate vaccines by decorating the surface of the nano or micro particulates with suitable ligands for targeted delivery. Oral vaccines, which can be delivered using particulate formulations, have the added potential to stimulate mucosa-associated lymphoid tissue located in the digestive tract and the gut-associated lymphoid tissue, both of which are important for the induction of effective mucosal response against many viruses. In addition, oral vaccines provide the opportunity to reduce production and administration costs and are very patient compliant. This review elaborately discusses different strategies that can be pursued to develop a nano or micro particulate oral vaccine for HPV induced cancers and other diseases.

Can short-term fasting protect against doxorubicin-induced cardiotoxicity?

Doxorubicin (Dox) is one of the most effective chemotherapeutic agents used in the treatment of several types of cancer. However the use is limited by cardiotoxicity. Despite extensive investigation into the mechanisms of toxicity and preventative strategies, Dox-induced cardiotoxicity still remains a major cause of morbidity and mortality in cancer survivors. Thus, continued research into preventative strategies is vital. Short-term fasting has proven to be cardioprotective against a variety of insults. Despite the potential, only a few studies have been conducted investigating its ability to prevent Dox-induced cardiotoxicity. However, all show proof-of-principle that short-term fasting is cardioprotective against Dox. Fasting affects a plethora of cellular processes making it difficult to discern the mechanism(s) translating fasting to cardioprotection, but may involve suppression of insulin and insulin-like growth factor-1 signaling with stimulated autophagy. It is likely that additional mechanisms also contribute. Importantly, the literature suggests that fasting may enhance the antitumor activity of Dox. Thus, fasting is a regimen that warrants further investigation as a potential strategy to prevent Dox-induced cardiotoxicity. Future research should aim to determine the optimal regimen of fasting, confirmation that this regimen does not interfere with the antitumor properties of Dox, as well as the underlying mechanisms exerting the cardioprotective effects.

Effects of acute doxorubicin treatment on hepatic proteome lysine acetylation status and the apoptotic environment.

AIM: To determine if doxorubicin (Dox) alters hepatic proteome acetylation status and if acetylation status was associated with an apoptotic environment. METHODS: Doxorubicin (20 mg/kg; Sigma, Saint Louis, MO; n = 8) or NaCl (0.9%; n = 7) was administered as an intraperitoneal injection to male F344 rats, 6-wk of age. Once animals were treated with Dox or saline, all animals were fasted until sacrifice 24 h later. RESULTS: Dox treatment decreased proteome lysine acetylation likely due to a decrease in histone acetyltransferase activity. Proteome deacetylation may likely not be associated with a proapoptotic environment. Dox did not increase caspase-9, -8, or -3 activation nor poly (adenosine diphosphate-ribose) polymerase-1 cleavage. Dox did stimulate caspase-12 activation, however, it likely did not play a role in apoptosis induction. CONCLUSION: Early effects of Dox involve hepatic proteome lysine deacetylation and caspase-12 activation under these experimental conditions.

Doxorubicin alters the mitochondrial dynamics machinery and mitophagy in the liver of treated animals.

Doxorubicin (Dox) is an effective chemotherapeutic agent, but known to cause cardiac and hepatic toxicity. Mechanisms of toxicity have not been clearly identified, but shown to involve oxidative stress and mitochondrial dysfunction. However, antioxidant supplementation has only shown modest protection from Dox-induced toxicity in clinical trials. Therefore, further research is required to discern alternative mechanisms that may also play an important role in Dox-induced toxicity. Thus, we aimed to investigate the role of mitochondrial fusion and fission in Dox-induced hepatic toxicity, which has not yet been investigated. Six-week-old male F344 rats were injected IP with 20 mg/kg of Dox or saline. Once administered, both groups of animals were fasted with no food or water until sacrifice 24 h later. Dox decreased content of primary regulators of mitochondrial fusion (OPA1, MFN1, and MFN2) with no effect on regulators of fission (DRP1 and FIS1), thus shifting the balance favoring mitochondrial fission. Moreover, it was determined that mitochondrial fission was likely not coupled to cell proliferation or cytochrome c release leading to the activation of mitochondrial-mediated apoptotic signaling. Rather, mitochondrial fission may be coupled to mitophagy and may be an adaptive response to protect against Dox-induced hepatic toxicity. This is the first study to report the role of altered mitochondrial dynamics and mitophagy machinery in Dox-induced hepatic injury.

The effects of acute doxorubicin treatment on proteome lysine acetylation status and apical caspases in skeletal muscle of fasted animals.

BACKGROUND: Doxorubicin treatment is known to cause muscular weakness. However, the cellular mechanisms have not been elucidated. We aimed to determine the effects of acute doxorubicin treatment on proteome lysine acetylation status, an indication of the apoptotic and inflammatory environment, and the expression and activation of various apical caspases involved in the initiation of apoptosis. METHODS: Six-week-old male F344 rats were injected intraperitoneally with 20 mg/kg of doxorubicin or saline. Once the treatment was administered, both groups of animals were fasted with no food or water until sacrifice 24 h posttreatment. RESULTS: Doxorubicin treatment affected neither the proteome lysine acetylation status nor the expression of sirtuin 1, sirtuin 3, SOD1, or SOD2 in soleus of fasted animals. Doxorubicin treatment also did not affect the expression or activation of procaspase-1, procaspase-8, procaspase-9, or procaspase-12. CONCLUSION: We suggest that doxorubicin does not exert a direct effect on these catabolic parameters in skeletal muscle in vivo.

Chemistry, biological activity, and chemotherapeutic potential of betulinic acid for the prevention and treatment of cancer and HIV infection.

3beta-Hydroxy-lup-20(29)-en-28-oic acid (betulinic acid) is a pentacyclic lupane-type triterpene that is widely distributed throughout the plant kingdom. A variety of biological activities have been ascribed to betulinic acid including anti-inflammatory and in vitro antimalarial effects. However, betulinic acid is most highly regarded for its anti-HIV-1 activity and specific cytotoxicity against a variety of tumor cell lines. Interest in developing even more potent anti-HIV agents based on betulinic acid has led to the discovery of a host of highly active derivatives exhibiting greater potencies and better therapeutic indices than some current clinical anti-HIV agents. While its mechanism of action has not been fully determined, it has been shown that some betulinic acid analogs disrupt viral fusion to the cell in a post-binding step through interaction with the viral glycoprotein gp41 whereas others disrupt assembly and budding of the HIV-1 virus. With regard to its anticancer properties, betulinic acid was previously reported to exhibit selective cytotoxicity against several melanoma-derived cell lines. However, more recent work has demonstrated that betulinic acid is cytotoxic against other non-melanoma (neuroectodermal and malignant brain tumor) human tumor varieties. Betulinic acid appears to function by means of inducing apoptosis in cells irrespective of their p53 status. Because of its selective cytotoxicity against tumor cells and favorable therapeutic index, even at doses up to 500 mg/kg body weight, betulinic acid is a very promising new chemotherapeutic agent for the treatment of HIV infection and cancer.