ACS Pharmacology and Translational Science最新文献

Colorectal cancer (CRC) is the third most common cancer worldwide, acting as a significant public health problem. 5-Fluorouracil (5-FU) is a key chemotherapy for various types of cancer, due to its broad anticancer activity. However, the emergence of drug resistance is a considerable limitation in the clinical application of 5-FU. Quercetin (QC) is proposed as an adjuvant therapy to minimize drug resistance to chemotherapeutics and enhance their pharmacological efficacy. The oral delivery of 5-FU and QC is challenged by poor aqueous solubility of QC and poor cellular permeability of 5-FU. To solve this issue, novel polylactide-co-glycolide (PLGA) combinatorial nanoparticles loading 5-FU and QC were prepared to deliver them directly to the colon. These sustained-release combinatorial nanoparticles recorded a significant decrease in cancer cell proliferation, C-reactive protein (CRP) level, and Interleukin-8 (IL-8) expression by 30.08%, 40.7%, and 46.6%, respectively. The results revealed that this combination therapy may offer a new strategy for the targeted delivery of chemotherapeutics to the colon.

Obesity and osteoporosis are two prevalent conditions that are becoming increasingly common worldwide, primarily due to aging populations, imbalanced energy intake, and sedentary lifestyles. Obesity, characterized by excessive fat accumulation, and osteoporosis, marked by reduced bone density and increased fracture risk, are often interconnected. High-fat diets (HFDs) can exacerbate both conditions by promoting bone marrow adiposity and bone loss. The effect of WFA on the osteogenesis and adipogenesis was studied on the C3H10T1/2 cell line and bone marrow mesenchymal stem cells (BM-MSCs) isolated from mice. We used oil red O and alkaline phosphatase (ALP) staining to observe adipogenesis and osteogenesis, respectively, in MSCs. Real-time PCR and Western blot analyses were used to study the molecular effects of WFA on MSCs. We employed micro-CT to analyze the bone microarchitecture, bone mineral density (BMD), and abdominal fat mass in male mice. We have used osmium tetroxide (OsO₄) staining to study the bone marrow fat. WFA induced the C3H10T1/2 cell line and BM-MSCs toward osteogenic lineage as evidenced by the higher ALP activity. WFA also downregulated the lipid droplet formation and adipocyte specific genes in MSCs. In the in vivo study, WFA also suppressed the bone catabolic effects of the HFD and maintained the bone microarchitecture and BMD in WFA-treated animals. The bone marrow adipose tissue was reduced in the tibia of WFA-treated groups in comparison with only HFD-fed animals. Withaferin A was able to improve the bone microarchitecture and BMD by committing BM-MSCs toward osteogenic differentiation and reducing marrow adiposity. The findings of this study could provide valuable insights into the therapeutic potential of Withaferin A for combating bone marrow obesity and osteoporosis, particularly in the context of diet-induced metabolic disturbances.

Linking an opioid to a nonopioid pharmacophore represents a promising approach for reducing opioid-induced side effects during pain management. Herein, we describe the optimization of the previously reported opioid-neurotensin hybrids (OPNT-hybrids), SBL-OPNT-05 & -10, containing the μ-/δ-opioid agonist H-Dmt-d-Arg-Aba-β-Ala-NH₂ and NT(8–13) analogs optimized for NTS2 affinity. In the present work, the constrained dipeptide Aba-β-Ala was modified to investigate the optimal linker length between the two pharmacophores, as well as the effect of expanding the aromatic moiety within constrained dipeptide analogs, via the inclusion of a naphthyl moiety. Additionally, the N-terminal Arg residue of the NT(8–13) pharmacophore was substituted with β³hArg. For all analogs, affinity was determined at the MOP, DOP, NTS1, and NTS2 receptors. Several of the hybrid ligands showed a subnanomolar affinity for MOP, improved binding for DOP compared to SBL-OPNT-05 & -10, as well as an excellent NTS2-affinity with high selectivity over NTS1. Subsequently, the G_αi1 and β-arrestin-2 pathways were evaluated for all hybrids, along with their stability in rat plasma. Upon MOP activation, SBL-OPNT-13 and -18 were the least effective at recruiting β-arrestin-2 (E_max = 17 and 12%, respectively), while both compounds were also found to be partial agonists at the G_αi1 pathway, despite improved potency compared to DAMGO. Importantly, these analogs also showed a half-life in rat plasma in excess of 48 h, making them valuable tools for future in vivo investigations.

Ubiquitination is a post-translational modification that elicits a variety of cellular responses. Deubiquitinases (DUBs) remove ubiquitin moieties from proteins and modulate cellular processes by counteracting the ubiquitin ligase activities. Ubiquitination and deubiquitination processes are tightly regulated by different mechanisms and their dysregulation is associated with many diseases. Discovery of DUB inhibitors could not only lead to therapeutics but also facilitate the understanding of ubiquitination/deubiquitination processes and their regulatory mechanisms. To enable the inhibitor discovery against DUBs, we developed a cell-based DUB assay that utilizes a cell-permeable ubiquitin probe, Biotin-cR₁₀-Ub-PA, to covalently label DUBs in their native cellular environment. Amplified luminescent proximity homogeneous assay (Alpha, specifically AlphaLISA) is utilized to quantitatively assess the capture of the target DUB by the Biotin-cR₁₀-Ub-PA probe. We demonstrated that this new cell-based DUB assay is robust and amenable to high-throughput screening. Human USP15 was selected as a DUB of interest and screened against a library of protease inhibitors as a proof of concept. In addition to the widely adopted pan-DUB inhibitor PR-619, several other DUB inhibitors from the library were also identified as hits. This new DUB assay can be readily adapted for inhibitor discovery against many other human DUBs to identify potent and cell-permeable inhibitors.

The therapeutic potential of small interfering RNAs (siRNAs) in gene-targeted treatments is substantial, but their suboptimal delivery impedes widespread clinical applications. Critical among these is the inability of siRNAs to traverse the cell membranes due to their anionic nature and high molecular weight. This limitation is particularly pronounced in lymphocytes, which pose additional barriers due to their smaller size and scant cytoplasm. Addressing this, we introduce an innovative lipid-conjugated polyethylenimine lipopolymer platform, engineered for delivery of therapeutic siRNAs into lymphocytes. This system utilizes the cationic nature of the polyethylenimine for forming stable complexes with anionic siRNAs, while the lipid component facilitates cellular entry of siRNA. The resulting lipopolymer/siRNA complexes are termed lipopolymer nanoparticles (LPNPs). We comprehensively profiled the efficacy of this platform in human peripheral blood mononuclear cells (PBMCs) as well as in vitro and in vivo models of acute lymphoblastic leukemia (ALL), emphasizing the inhibition of the oncogenic signal transducer and activator of transcription 5A (STAT5A) gene. The lipopolymers demonstrated high efficiency in delivering siRNA to ALL cell lines (RS4;11 and SUP-B15) and primary patient cells, effectively silencing the STAT5A gene. The resultant gene silencing induced apoptosis and significantly reduced colony formation in vitro. Furthermore, in vivo studies showed a significant decrease in tumor volumes without causing substantial toxicity. The lipopolymers did not induce the secretion of proinflammatory cytokines (IL-6, TNF-α, and INF-γ) in PBMCs from healthy volunteers, underscoring their immune safety profile. Our observations indicate that LPNP-based siRNA delivery systems offer a promising therapeutic approach for ALL in terms of both safety and therapeutic efficacy.

Brain aging is associated with cognitive decline, reduced synaptic plasticity, and altered metabolism. The activity of mechanistic target of rapamycin (mTOR) has a major impact on aging by regulating cellular metabolism. Although reduced mTOR signaling has a general antiaging effect, it can negatively affect the aging brain by reducing synaptogenesis and thus cognitive functions. Increased mTOR activity facilitates aging and is responsible for the amnestic effect of the cannabinoid receptor 1 agonist Δ⁹-tetrahydrocannabinol (THC) in higher doses. Long-term low-dose Δ⁹-THC had an antiaging effect on the brain by restoring cognitive abilities and synapse densities in old mice. Whether changes in mTOR signaling and metabolome are associated with its positive effects on the aging brain is an open question. Here, we show that Δ⁹-THC treatment has a tissue-dependent and dual effect on mTOR signaling and the metabolome. In the brain, Δ⁹-THC treatment induced a transient increase in mTOR activity and in the levels of amino acids and metabolites involved in energy production, followed by an increased synthesis of synaptic proteins. Unexpectedly, we found a similar reduction in the mTOR activity in adipose tissue and in the level of amino acids and carbohydrate metabolites in blood plasma as in animals on a low-calorie diet. Thus, long-term Δ⁹-THC treatment first increases the level of energy and synaptic protein production in the brain, followed by a reduction in mTOR activity and metabolic processes in the periphery. Our study suggests that a dual effect on mTOR activity and the metabolome could be the basis for an effective antiaging and pro-cognitive medication.

Telomeres are a protective cap that prevents chromosome ends from being recognized as double-stranded breaks. In somatic cells, telomeres shorten with each cell division due to the end replication problem, which eventually leads to senescence, a checkpoint proposed to prevent uncontrolled cell growth. Tumor cells avoid telomere shortening by activating one of two telomere maintenance mechanisms (TMMs): telomerase reactivation or alternative lengthening of telomeres (ALT). TMMs are a viable target for cancer treatment as they are not active in normal, differentiated cells. Whereas there is a telomerase inhibitor currently undergoing clinical trials, there are no known ALT inhibitors in development, partially because the complex ALT pathway is still poorly understood. For cancers such as neuroblastoma and osteosarcoma, the ALT-positive status is associated with an aggressive phenotype and few therapeutic options. Thus, methods that characterize the key biological pathways driving ALT will provide important mechanistic insight. We have developed a first-in-class phenotypic high-throughput screen to identify small-molecule inhibitors of ALT. Our screen measures relative C-circle level, an ALT-specific biomarker, to detect changes in ALT activity induced by compound treatment. To investigate epigenetic mechanisms that contribute to ALT, we screened osteosarcoma and neuroblastoma cells against an epigenetic-targeted compound library. Hits included compounds that target chromatin-regulating proteins and DNA damage repair pathways. Overall, the high-throughput C-circle assay will help expand the repertoire of potential ALT-specific therapeutic targets and increase our understanding of ALT biology.

The role of autotaxin (ATX)-lysophosphatidic acid (LPA) is yet to be explored in the context of liver cirrhosis and associated encephalopathy. Our objective of this study was to evaluate the role of an ATX inhibitor in biliary cirrhosis and associated hepatic encephalopathy in rats. The preliminary investigation revealed significant impairment in liver function, which eventually led to the development of hepatic encephalopathy. Interestingly, LPA levels were significantly increased in the plasma, liver, and brain of rats following bile duct ligation. Subsequently, we tested the efficacy of an ATX inhibitor, CBT-295, in bile duct-induced biliary cirrhosis and neuropsychiatric symptoms associated with hepatic encephalopathy. CBT-295 showed good oral bioavailability and favorable pharmacokinetic properties. CBT-295 exhibited a significant reduction in inflammatory cytokines like TGF-β, TNF-α, and IL-6 levels, also reduced bile duct proliferation marker CK-19, and lowered liver fibrosis, as evident from reduced collagen deposition. The reversal of liver fibrosis with CBT-295 led to a reduction in blood and brain ammonia levels. Furthermore, CBT-295 also reduced neuroinflammation induced by ammonia, which is characterized by a significant reduction in brain cytokine levels. It improved neuropsychiatric symptoms such as locomotor activities, cognitive impairment, and clinical grading scores associated with hepatic encephalopathy. The improvement in hepatic encephalopathy observed with the ATX inhibitor could be the result of its hepatoprotective action and its ability to attenuate neuroinflammation. Therefore, inhibition of ATX-LPA signaling can be a multifactorial approach for the treatment of chronic liver diseases.

Mainstream treatment modalities which dominate the therapeutic landscape of prostate cancer (PCa) are prostatectomy, radiation therapy, and androgen deprivation therapy (ADT) or castration. These therapeutic options can extend the life expectancy of the patients but eventually fail to completely cure the disease. Despite undergoing ADT, patients still experience disease recurrence. One of the reasons for this recurrence is the binding of the basal androgens present in blood plasma to the androgen receptor (AR). At this stage, the disease becomes castration-resistant prostate cancer (CRPC) showing resistance to ADT promoting progression, and there is no effective treatment available. Although another male cancer such as testicular cancer responds to cisplatin-based therapy very well, PCa is resistant to cisplatin. In our continued effort to find the pathways that are important for such resistance, we link in this report, tumor metabolism driven androgen regulation and PCa resistance toward cisplatin-based therapy. To delve deeper into understanding how metabolic modulatory cisplatin prodrugs can be used to target the ADT resistant population, we demonstrate that metabolic inhibition by a cisplatin prodrug, Platin-L has the potential to modulate AR activity and resensitize ADT resistant cells toward cisplatin-based chemotherapy as well as ADT. The mode of action for Platin-L is inhibition of fatty acid oxidation (FAO) of prostate cancer cells. We demonstrated that FAO inhibition by Platin-L in PCa cells contribute to AR regulation resulting in altered tumorigenicity of androgen sensitive prostate cancer.

6-Nitrobenzo[b]thiophene 1,1-dioxide (Stattic) is a potent signal transducer and activator of the transcription 3 (STAT3) inhibitor developed originally for anticancer therapy. However, Stattic harbors several STAT3 inhibition-independent biological effects. To improve the properties of Stattic, we prepared a series of analogues derived from 6-aminobenzo[b]thiophene 1,1-dioxide, a compound directly obtained from the reduction of Stattic, that includes a methoxybenzylamino derivative (K2071) with optimized physicochemical characteristics, including the ability to cross the blood–brain barrier. Besides inhibiting the interleukin-6-stimulated activity of STAT3 mediated by tyrosine 705 phosphorylation, K2071 also showed cytotoxicity against a set of human glioblastoma-derived cell lines. In contrast to the core compound, a part of K2071 cytotoxicity reflected a STAT3 inhibition-independent block of mitotic progression in the prophase, affecting mitotic spindle formation, indicating that K2071 also acts as a mitotic poison. Compared to Stattic, K2071 was significantly less thiol-reactive. In addition, K2071 affected cell migration, suppressed cell proliferation in tumor spheroids, exerted cytotoxicity for glioblastoma temozolomide-induced senescent cells, and inhibited the secretion of the proinflammatory cytokine monocyte chemoattractant protein 1 (MCP-1) in senescent cells. Importantly, K2071 was well tolerated in mice, lacking manifestations of acute toxicity. The structure–activity relationship analysis of the K2071 molecule revealed the necessity of the para-substituted methoxyphenyl motif for antimitotic but not overall cytotoxic activity of its derivatives. Altogether, these results indicate that compound K2071 is a novel Stattic-derived STAT3 inhibitor and a mitotic poison with anticancer and senotherapeutic properties that is effective on glioblastoma cells and may be further developed as an agent for glioblastoma therapy.