Sildenafil Potentiates the Therapeutic Efficacy of Docetaxel in Advanced Prostate Cancer by Stimulating NO-cGMP Signaling

In vitro dissolution equivalence of Jordanian sildenafil generics via validated, stability-indicating HPLC method

This study was conducted to compare dissolution profiles of four Jordanian registered sildenafil (SDF) products to the originator. Dissolution samples were analyzed utilizing a validated and stability-indicating HPLC method in human plasma. Validation was performed for specificity, linearity, limit of detection, lower limit of quantification, precision, trueness and stability. SDF was extracted from plasma samples using liquid-liquid extraction. The analysis was performed utilizing isocratic elution on C18 column with 1.0 ml/min flow rate. The regression value was ∼0.999 over 3 days with drug recovery between 86.6 to 89.8%with 10 ng/ml lower limit of quantitation. This method displayed a good selectivity of SDF with improved stability under various conditions. The method was used for SDF quantification in dissolution medium. Similarity factors for local products varied according to the used mediums, but all SDF local products passed the dissolution in vitro test since all of them showed a released of >85% after 60 min at the dissolution mediums.

Natural Targeting Potent ROS-Eliminating Tungsten-Based Polyoxometalate Nanodots for Efficient Treatment of Pulmonary Hypertension

Pulmonary hypertension (PH) is a disease of pulmonary artery stenosis and blockage caused by abnormal pulmonary artery smooth muscle cells (PASMCs), with high morbidity and mortality. High levels of reactive oxygen species (ROS) in pulmonary arteries play a crucial role in inducing phenotypic switch and abnormal proliferation of PASMCs. However, antioxidants are rarely approved for the treatment of PH because of a lack of targeting and low bioavailability. In this study, the presence of an enhanced permeability and retention effect (EPR)-like effect in the pulmonary arteries of PH is revealed by tissue transmission electron microscopy (TEM). Subsequently, for the first time, tungsten-based polyoxometalate nanodots (WNDs) are developed with potent elimination of multiple ROS for efficient treatment of PH thanks to the high proportion of reduced W5+ . WNDs are effectively enriched in the pulmonary artery by intravenous injection because of the EPR-like effect of PH, and significantly prevent the abnormal proliferation of PASMCs, greatly improve the remodeling of pulmonary arteries, and ultimately improve right heart function. In conclusion, this work provides a novel and effective solution to the dilemma of targeting ROS for the treatment of PH.

Understanding human aging and the fundamental cell signaling link in age-related diseases: the middle-aging hypovascularity hypoxia hypothesis

Aging-related hypoxia, oxidative stress, and inflammation pathophysiology are closely associated with human age-related carcinogenesis and chronic diseases. However, the connection between hypoxia and hormonal cell signaling pathways is unclear, but such human age-related comorbid diseases do coincide with the middle-aging period of declining sex hormonal signaling. This scoping review evaluates the relevant interdisciplinary evidence to assess the systems biology of function, regulation, and homeostasis in order to discern and decipher the etiology of the connection between hypoxia and hormonal signaling in human age-related comorbid diseases. The hypothesis charts the accumulating evidence to support the development of a hypoxic milieu and oxidative stress-inflammation pathophysiology in middle-aged individuals, as well as the induction of amyloidosis, autophagy, and epithelial-to-mesenchymal transition in aging-related degeneration. Taken together, this new approach and strategy can provide the clarity of concepts and patterns to determine the causes of declining vascularity hemodynamics (blood flow) and physiological oxygenation perfusion (oxygen bioavailability) in relation to oxygen homeostasis and vascularity that cause hypoxia (hypovascularity hypoxia). The middle-aging hypovascularity hypoxia hypothesis could provide the mechanistic interface connecting the endocrine, nitric oxide, and oxygen homeostasis signaling that is closely linked to the progressive conditions of degenerative hypertrophy, atrophy, fibrosis, and neoplasm. An in-depth understanding of these intrinsic biological processes of the developing middle-aged hypoxia could provide potential new strategies for time-dependent therapies in maintaining healthspan for healthy lifestyle aging, medical cost savings, and health system sustainability.

Functional Axis of PDE5/cGMP Mediates Timosaponin-AIII-Elicited Growth Suppression of Glioblastoma U87MG Cells

Glioblastoma (GBM) is the most aggressive brain tumor, with high mortality. Timosaponin AIII (TIA), a steroidal saponin isolated from the medicinal plant Anemarrhena asphodeloides Bge., has been shown to possess anticancer properties in various cancer types. However, the effect of TIA on GBM is unknown. In this study, we reveal that TIA not only inhibited U87MG in vitro cell growth but also in vivo tumor development. Moreover, we found that the cause of TIA-induced cell growth suppression was apoptosis. When seeking to uncover antitumor mechanisms of TIA, we found that TIA diminished the expression of cGMP-specific phosphodiesterase 5(PDE5) while elevating the levels of guanylate cyclases (sGCβ), cellular cGMP, and phosphorylation of VASP^ser239. Following the knockdown of PDE5, PDE5 inhibitor tadalafil and cGMP analog 8-Bro-cGMP both inhibited cell growth and inactivated β-catenin; we reason that TIA elicited an antitumor effect by suppressing PDE5, leading to the activation of the cGMP signaling pathway, which, in turn, impeded β-catenin expression. As β-catenin is key for cell growth and survival in GBM, this study suggests that TIA elicits its anti-tumorigenic effect by interfering with β-catenin function through the activation of a PDE5/cGMP functional axis.

Immunomodulatory, apoptotic and anti-proliferative potentials of sildenafil in Ehrlich ascites carcinoma murine model: In vivo and in silico insights

Sildenafil is a potent phosphodiesterase-5 (PDE5) inhibitor that effectively inhibits cGMP and increases the strength of nitric oxide. PDE5 was overexpressed in several carcinomas, including breast cancer, which inhibited tumor growth and cell division. The current research aims to investigate the in vivo sildenafil's immunomodulatory and antineoplastic potentials against Ehrlich Ascites Carcinoma. This study looked at the effects of sildenafil mono-treatment and co-treatment with cisplatin; tumor cell count, viability and the inhibition rate were determined. Apoptosis, cell cycle distribution, alterations in tumor cells and splenocytes proliferation, changes in splenocytes immunophenotyping using flowcytometry, plasma levels of malondialdehyde (MDA), reduced glutathione (GSH), interferone (IFN)-γ, granzyme B, alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, creatinine and hematological alterations were detected. Additionally, docking study was conducted to get further insights on how Sildenafil exerts its activity. Sildenafil mono-treatment and co-treatment with cisplatin markedly reduced tumor cell count, viability, growth rate and proliferative capability accompanied by apoptosis enhancement and G₀/G₁ and sub G₁ cells cycle arrest. Fortunately, sildenafil evoked efficient cellular immune response by increasing plasma levels of granzyme B and IFN-γ, proportion of splenic T cytotoxic (CD3⁺CD8⁺) and T helper (CD3⁺CD4⁺), accompanied by decrease in the proportion of splenic regulatory T cells. . Moreover, in silico data suggest LcK and MAPKs as the potential targets of sildenafil. Furthermore, sildenafil rebalanced the oxidant-antioxidant status by decreasing MDA and increasing GSH plasma levels. Sildenafil successfully retrieved various hematological values besides renal and hepatic functions in EAC-bearing animals. In conclusion, our results suggest that sildenafil could be potential safe anti-tumor agent with immuno-modulatory properties against Ehrlich ascites carcinoma.

Androgen-deprivation therapy with leuprolide increases abdominal adiposity without causing cardiac dysfunction in middle-aged male mice: effect of sildenafil

Androgen-deprivation therapy (ADT) is the primary systemic therapy for treating advanced or metastatic prostate cancer (PCa), which has improved survival outcomes in patients with PCa. However, ADT may develop metabolic and cardiovascular adverse events that impact the quality of life and lifespan in PCa survivors. The present study was designed to establish a murine model of ADT with a gonadotropin-releasing hormone (GnRH) agonist leuprolide and to investigate its effects on metabolism and cardiac function. We also examined the potential cardioprotective role of sildenafil (inhibitor of phosphodiesterase 5) under chronic ADT. Middle-aged male C57BL/6J mice received a 12-wk subcutaneous infusion via osmotic minipumps containing either saline or 18 mg/4 wk leuprolide with or without 1.3 mg/4 wk sildenafil cotreatment. Compared with saline controls, leuprolide treatment significantly reduced prostate weight and serum testosterone levels, confirming chemical castration in these mice. The ADT-induced chemical castration was not affected by sildenafil. Leuprolide significantly increased the weight of abdominal fat after 12-wk treatment without a change in total body weight, and sildenafil did not block the proadipogenic effect of leuprolide. No signs of left ventricular systolic and diastolic dysfunction were observed throughout the leuprolide treatment period. Interestingly, leuprolide treatment significantly elevated serum levels of cardiac troponin I (cTn-I), a biomarker of cardiac injury, and sildenafil did not abolish this effect. We conclude that long-term ADT with leuprolide increases abdominal adiposity and cardiac injury biomarker without cardiac contractile dysfunction. Sildenafil did not prevent ADT-associated adverse changes.

Heterogeneity of cGMP signalling in tumour cells and the tumour microenvironment: Challenges and chances for cancer pharmacology and therapeutics

The second messenger cyclic guanosine monophosphate (cGMP) is an important regulator of human (patho-)physiology and has emerged as an attractive drug target. Currently, cGMP-elevating drugs are mainly used to treat cardiovascular diseases, but there is also increasing interest in exploring their potential for cancer prevention and therapy. In this review article, we summarise recent findings in cancer-related cGMP research, with a focus on melanoma, breast cancer, colorectal cancer, prostate cancer, glioma, and ovarian cancer. These studies indicate tremendous heterogeneity of cGMP signalling in tumour tissue. It appears that different tumour and stroma cells, and perhaps different sexes, express different cGMP generators, effectors, and degraders. Therefore, the same cGMP-elevating drug can lead to different outcomes in different tumour settings, ranging from inhibition to promotion of tumourigenesis or therapy resistance. These findings, together with recent evidence that increased cGMP signalling is associated with worse prognosis in several human cancers, challenge the traditional view that cGMP elevation generally has an anti-cancer effect. As cGMP pathways appear to be more stable in the stroma than in tumour cells, we suggest that cGMP-modulating drugs should preferentially target the tumour microenvironment. Indeed, there is evidence that phosphodiesterase 5 inhibitors like sildenafil enhance anti-tumour immunity by acting on immune cells. Moreover, many in vivo results obtained with cGMP-modulating drugs could be explained by effects on the tumour vasculature rather than on the tumour cells themselves. We therefore propose a model that incorporates the NO/cGMP signalling pathway in tumour vessels as a key target for cancer therapy. Deciphering the multifaceted roles of cGMP in cancer is not only a challenge for basic research, but also provides a chance to predict potential adverse effects of cGMP-modulating drugs in cancer patients and to develop novel anti-tumour therapies by precision targeting of the relevant cells and molecular pathways.

Beyond Erectile Dysfunction: cGMP-Specific Phosphodiesterase 5 Inhibitors for Other Clinical Disorders

Cyclic guanosine monophosphate (cGMP), an important intracellular second messenger, mediates cellular functional responses in all vital organs. Phosphodiesterase 5 (PDE5) is one of the 11 members of the cyclic nucleotide phosphodiesterase (PDE) family that specifically targets cGMP generated by nitric oxide-driven activation of the soluble guanylyl cyclase. PDE5 inhibitors, including sildenafil and tadalafil, are widely used for the treatment of erectile dysfunction, pulmonary arterial hypertension, and certain urological disorders. Preclinical studies have shown promising effects of PDE5 inhibitors in the treatment of myocardial infarction, cardiac hypertrophy, heart failure, cancer and anticancer-drug-associated cardiotoxicity, diabetes, Duchenne muscular dystrophy, Alzheimer's disease, and other aging-related conditions. Many clinical trials with PDE5 inhibitors have focused on the potential cardiovascular, anticancer, and neurological benefits. In this review, we provide an overview of the current state of knowledge on PDE5 inhibitors and their potential therapeutic indications for various clinical disorders beyond erectile dysfunction.

Application of single-point prostate biopsy in elderly patients with highly suspected prostate cancer

Objective

To explore the feasibility of single-point prostate biopsy in elderly patients with highly suspected prostate cancer.

Methods

Forty-three patients with a prostate imaging reporting and data system score (PI-RADS) of 5, age ≥ 80 years and/or PSA ≥ 100 ng/ml and/or Eastern Cooperative Oncology Group score ≥ 2 were enrolled in our hospital from March 2020 to June 2022. Targeted surgery of these patients was performed using only precise local anesthesia in the biopsy area. The biopsy tissues were examined by intraoperative frozen section examination (IFSE). If the result of IFSE was negative, traditional systematic biopsy and further routine pathological examination were performed. The positive rate of biopsy, operation time, complications and pain score were recorded.

Results

The positive rate of prostate biopsy was 94.7%. The results of IFSE in two patients were negative, and the routine pathological results of further systematic biopsy of those patients were also negative. The visual analog scale and visual numeric scale were 2 (2-4) and 3 (2-3), respectively, during the biopsy procedure. The mean time of operation was 8.5 ± 2.1 min from the beginning of anesthesia to the end of biopsy. It took 35.3 ± 18.7 minutes to obtain the pathological report of IFSE. The incidences of complication hematuria and urinary retention were 10.5% and 2.6%, respectively.

Conclusion

For elderly patients with highly suspected prostate cancer, single-point prostate biopsy can be used to quickly and safely obtain pathological results.

DNA-gold nanoprobe-based integrated biosensing technology for non-invasive liquid biopsy of serum miRNA: A new frontier in prostate cancer diagnosis

The low specificity of prostate-specific antigen contributes to overdiagnosis and ov ertreatment of prostate cancer (PCa) patients. Hence, there is an urgent need for inclusive diagnostic platforms that could improve the diagnostic accuracy of PCa. Dysregulated miRNAs are closely associated with the progression and recurrence and have emerged as promising diagnostic and prognostic biomarkers for PCa. Nevertheless, simple, rapid, and ultrasensitive quantification of serum miRNAs is highly challenging. This study designed, synthesized, and demonstrated the practicability of DNA-linked gold nanoprobes (DNA-AuNPs) for the single-step quantification of miR-21/miR-141/miR-375. In preclinical study, the assay differented PCa Pten conditional knockout (Pten^cKO) mice compared to their age-matched Pten wild-type (Pten^WT) control mice. In human sera, receiver operating characteristic (ROC) curve-based correlation analyses revealed clear discrimination between PCa patients from normal healthy controls using training and validation sets. Overall, we established integrated nano-biosensing technology for the PCR-free, non-invasive liquid biopsies of multiple miRNAs for PCa diagnosis.

Delivery of therapeutic oligonucleotides in nanoscale

Therapeutic oligonucleotides (TOs) represent one of the most promising drug candidates in the targeted cancer treatment due to their high specificity and capability of modulating cellular pathways that are not readily druggable. However, efficiently delivering of TOs to cancer cellular targets is still the biggest challenge in promoting their clinical translations. Emerging as a significant drug delivery vector, nanoparticles (NPs) can not only protect TOs from nuclease degradation and enhance their tumor accumulation, but also can improve the cell uptake efficiency of TOs as well as the following endosomal escape to increase the therapeutic index. Furthermore, targeted and on-demand drug release of TOs can also be approached to minimize the risk of toxicity towards normal tissues using stimuli-responsive NPs. In the past decades, remarkable progresses have been made on the TOs delivery based on various NPs with specific purposes. In this review, we will first give a brief introduction on the basis of TOs as well as the action mechanisms of several typical TOs, and then describe the obstacles that prevent the clinical translation of TOs, followed by a comprehensive overview of the recent progresses on TOs delivery based on several various types of nanocarriers containing lipid-based nanoparticles, polymeric nanoparticles, gold nanoparticles, porous nanoparticles, DNA/RNA nanoassembly, extracellular vesicles, and imaging-guided drug delivery nanoparticles.

Pros and Cons of Pharmacological Manipulation of cGMP-PDEs in the Prevention and Treatment of Breast Cancer

The cyclic nucleotides, cAMP and cGMP, are ubiquitous second messengers responsible for translating extracellular signals to intracellular biological responses in both normal and tumor cells. When these signals are aberrant or missing, cells may undergo neoplastic transformation or become resistant to chemotherapy. cGMP-hydrolyzing phosphodiesterases (PDEs) are attracting tremendous interest as drug targets for many diseases, including cancer, where they regulate cell growth, apoptosis and sensitization to radio- and chemotherapy. In breast cancer, PDE5 inhibition is associated with increased intracellular cGMP levels, which is responsible for the phosphorylation of PKG and other downstream molecules involved in cell proliferation or apoptosis. In this review, we provide an overview of the most relevant studies regarding the controversial role of PDE inhibitors as off-label adjuvants in cancer therapy.

The Potential Role of Sildenafil in Cancer Management through EPR Augmentation

Enhanced permeation retention (EPR) was a significant milestone discovery by Maeda et al. paving the path for the emerging field of nanomedicine to become a powerful tool in the fight against cancer. Sildenafil is a potent inhibitor of phosphodiesterase 5 (PDE-5) used for the treatment of erectile dysfunction (ED) through the relaxation of smooth muscles and the modulation of vascular endothelial permeability. Overexpression of PDE-5 has been reported in lung, colon, metastatic breast cancers, and bladder squamous carcinoma. Moreover, sildenafil has been reported to increase the sensitivity of tumor cells of different origins to the cytotoxic effect of chemotherapeutic agents with augmented apoptosis mediated through inducing the downregulation of Bcl-xL and FAP-1 expression, enhancing reactive oxygen species (ROS) generation, phosphorylating BAD and Bcl-2, upregulating caspase-3,8,9 activities, and blocking cells at G0/G1 cell cycle phase. Sildenafil has also demonstrated inhibitory effects on the efflux activity of ATP-binding cassette (ABC) transporters such as ABCC4, ABCC5, ABCB1, and ABCG2, ultimately reversing multidrug resistance. Accordingly, there has been a growing interest in using sildenafil as monotherapy or chemoadjuvant in EPR augmentation and management of different types of cancer. In this review, we critically examine the basic molecular mechanism of sildenafil related to cancer biology and discuss the overall potential of sildenafil in enhancing EPR-based anticancer drug delivery, pointing to the outcomes of the most important related preclinical and clinical studies.

Role of phosphodiesterase 1 in the pathophysiology of diseases and potential therapeutic opportunities

Cyclic nucleotide phosphodiesterases (PDEs) are superfamily of enzymes that regulate the spatial and temporal relationship of second messenger signaling in the cellular system. Among the 11 different families of PDEs, phosphodiesterase 1 (PDE1) sub-family of enzymes hydrolyze both 3',5'-cyclic adenosine monophosphate (cAMP) and 3',5'-cyclic guanosine monophosphate (cGMP) in a mutually competitive manner. The catalytic activity of PDE1 is stimulated by their binding to Ca²⁺/calmodulin (CaM), resulting in the integration of Ca²⁺ and cyclic nucleotide-mediated signaling in various diseases. The PDE1 family includes three subtypes, PDE1A, PDE1B and PDE1C, which differ for their relative affinities for cAMP and cGMP. These isoforms are differentially expressed throughout the body, including the cardiovascular, central nervous system and other organs. Thus, PDE1 enzymes play a critical role in the pathophysiology of diseases through the fundamental regulation of cAMP and cGMP signaling. This comprehensive review provides the current research on PDE1 and its potential utility as a therapeutic target in diseases including the cardiovascular, pulmonary, metabolic, neurocognitive, renal, cancers and possibly others.

Current Advances of Nitric Oxide in Cancer and Anticancer Therapeutics

Nitric oxide (NO) is a short-lived, ubiquitous signaling molecule that affects numerous critical functions in the body. There are markedly conflicting findings in the literature regarding the bimodal effects of NO in carcinogenesis and tumor progression, which has important consequences for treatment. Several preclinical and clinical studies have suggested that both pro- and antitumorigenic effects of NO depend on multiple aspects, including, but not limited to, tissue of generation, the level of production, the oxidative/reductive (redox) environment in which this radical is generated, the presence or absence of NO transduction elements, and the tumor microenvironment. Generally, there are four major categories of NO-based anticancer therapies: NO donors, phosphodiesterase inhibitors (PDE-i), soluble guanylyl cyclase (sGC) activators, and immunomodulators. Of these, NO donors are well studied, well characterized, and also the most promising. In this study, we review the current knowledge in this area, with an emphasis placed on the role of NO as an anticancer therapy and dysregulated molecular interactions during the evolution of cancer, highlighting the strategies that may aid in the targeting of cancer.