Parkinson’s disease (PD) significantly affects patients’ quality of life and represents a high economic burden for health systems. Given the lack of safe and effective treatments for PD, drug repositioning seeks to offer new medication alternatives, reducing research time and costs compared to the traditional drug development strategy. This review aimed to collect evidence of drugs proposed as candidates to be reused in PD and identify those with the potential to be reformulated into nanocarriers to optimize future repositioning trials. We conducted a detailed search in PubMed, Web of Science, and Scopus from January 2015 at the end of 2021, with the descriptors “Parkinson’s disease” and “drug repositioning” or “drug repurposing”. We identified 28 drugs as potential candidates, and six of them were found in repositioning clinical trials for PD. However, a limitation of many of these drugs to achieve therapeutic success is their inability to cross the blood–brain barrier (BBB), as is the case with nilotinib, which has shown promising outcomes in clinical trials. We suggest reformulating these drugs in biodegradable nanoparticles (NPs) based on lipids and polymers to perform future trials. As a complementary strategy, we propose functionalizing the NPs surface by adding materials to the surface layer. Among other advantages, functionalization can promote efficient crossing through the BBB and improve the affinity of NPs towards certain brain regions. The main parameters to consider for the design of NPs targeting the central nervous system are highlighted, such as size, PDI, morphology, drug load, and Z potential. Finally, current advances in the use of NPs for Parkinson's disease are cited.

Retinoblastoma is the most common pediatric intraocular malignant tumor. Unfortunately, low cure rates and low life expectancy are observed in low-income countries. Thus, alternative therapies are needed for patients who do not respond to current treatments or those with advanced cases of the disease. Ether à-go-go-1 (Eag1) is a voltage-gated potassium channel involved in cancer. Eag1 expression is upregulated by the human papilloma virus (HPV) oncogene E7, suggesting that retinoblastoma protein (pRb) may regulate Eag1. Astemizole is an antihistamine that is suggested to be repurposed for cancer treatment; it targets proteins implicated in cancer, including histamine receptors, ATP binding cassette transporters, and Eag channels. Here, we investigated Eag1 regulation using pRb and Eag1 expression in human retinoblastoma. The effect of astemizole on the cell proliferation of primary human retinoblastoma cultures was also studied. HeLa cervical cancer cells (HPV-positive and expressing Eag1) were transfected with RB1. Eag1 mRNA expression was studied using qPCR, and protein expression was assessed using western blotting and immunochemistry. Cell proliferation was evaluated with an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. RB1 transfection down-regulated Eag1 mRNA and protein expression. The human retinoblastoma samples displayed heterogeneous Eag1 mRNA and protein expression. Astemizole decreased cell proliferation in primary retinoblastoma cultures. Our results suggest that Eag1 mRNA and protein expression was regulated by pRb in vitro, and that human retinoblastoma tissues had heterogeneous Eag1 mRNA and protein expression. Furthermore, our results propose that the multitarget drug astemizole may have clinical relevance in patients with retinoblastoma, for instance, in those who do not respond to current treatments.

The D₁R and D₃R receptors functionally and synergistically interact in striatonigral neurons. Dopaminergic denervation turns this interaction antagonistic, which is correlated with a decrement in D₃nf isoform and an increment in D₃R membranal expression. The mechanisms of such changes in D₃R are attributed to the dysregulation of the expression of their isoforms. The cause and mechanism of this phenomenon remain unknown. Dopaminergic denervation produces a decrement in D₁R and PKA activity; we propose that the lack of phosphorylation of PTB (regulator of alternative splicing) by PKA produces the dysregulation of D₃R splicing and changes D₃R functionality. By using in silico analysis, we found that D₃R mRNA has motifs for PTB binding and, by RIP, co-precipitates with PTB. Moreover, D₁R activation via PKA promotes PTB phosphorylation. Acute and 5-day D₁R blockade decreases the expression of D₃nf mRNA. The 5-day treatment reduces D₃R, D₃nf, and PTB protein in the cytoplasm and increases D₃R in the membrane and PTB in the nucleus. Finally, the blockade of D₁R mimics the effect of dopaminergic denervation in D₁R and D₃R signaling. Thus, our data indicate that through PKA→PTB, D₁R modulates D₃R splicing, expression, and signaling, which are altered during D₁R blockade or the lack of stimulation in dopaminergic denervation.

Sea anemones are an important source of bioactive compounds with potential pharmacological applications. Their toxins are produced and stored in organelles called nematocysts and act on specific targets, including voltage-gated ion channels. To date, sea anemone toxins have demonstrated effects on voltage-gated sodium and potassium channels, facilitating investigations into the structure and function of these proteins. In this study, we evaluated the effect of Bunodeopsis globulifera sea anemone crude extract, and of a low molecular weight fraction, on voltage-gated sodium and calcium channels within the murine nervous system. Notably, the crude extract led to a significant reduction in total sodium current, while also triggering calcium-dependent glutamate release. Furthermore, the low molecular weight fraction, in particular, enhanced total calcium currents and current density. These findings underscore the existence of sea anemone toxins with diverse mechanisms of action beyond those previously documented.

Hepatocellular carcinoma (HCC) is the main type of liver cancer and one of the malignancies with the highest mortality rates worldwide. HCC is associated with diverse etiological factors including alcohol use, viral infections, fatty liver disease, and liver cirrhosis (a major risk factor for HCC). Unfortunately, many patients are diagnosed at advanced stages of the disease and receive palliative treatment only. Therefore, early markers of HCC and novel therapeutic approaches are urgently needed. The endocannabinoid system is involved in various physiological processes such as motor coordination, emotional control, learning and memory, neuronal development, antinociception, and immunological processes. Interestingly, endocannabinoids modulate signaling pathways involved in cell survival, proliferation, apoptosis, autophagy, and immune response. Consistently, several cannabinoids have demonstrated potential antitumor properties in experimental models. The participation of metabotropic and ionotropic cannabinoid receptors in the biological effects of cannabinoids has been extensively described. In addition, cannabinoids interact with other targets, including several ion channels. Notably, several ion channels targeted by cannabinoids are involved in inflammation, proliferation, and apoptosis in liver diseases, including HCC. In this literature review, we describe and discuss both the endocannabinoid system and exogenous phytocannabinoids, such as cannabidiol and Δ⁹-tetrahydrocannabinol, along with their canonical receptors, as well as the cannabidiol-targeted ion channels and their role in liver cancer and its preceding liver diseases. The cannabidiol-ion channel association is an extraordinary opportunity in liver cancer prevention and therapy, with potential implications for several environments that are for the benefit of cancer patients, including sociocultural, public health, and economic systems.