O-GlcNAcylation in tumorigenesis and its implications for cancer therapy.

O-linked N-acetylglucosaminylation (O-GlcNAcylation) is a dynamic and reversible posttranslational modification that targets serine and threonine residues in a variety of proteins. Uridine diphospho-N-acetylglucosamine (UDP-GlcNAc), which is synthesized from glucose via the hexosamine biosynthesis pathway, is the major donor of this modification. O-GlcNAc transferase (OGT) is the sole enzyme that transfers GlcNAc onto protein substrates, while O-GlcNAcase (OGA) is responsible for removing this modification. O-GlcNAcylation plays an important role in tumorigenesis and progression through the modification of specific protein substrates. In this review, we discuss the tumor-related biological functions of O-GlcNAcylation and summarize the recent progress in the development of pharmaceutical options to manipulate the O-GlcNAcylation of specific proteins as potential anticancer therapies.

Discovery of a peptide proteolysis-targeting chimera (PROTAC) drug of p300 for prostate cancer therapy.

BACKGROUND: The E1A-associated protein p300 (p300) has emerged as a promising target for cancer therapy due to its crucial role in promoting oncogenic signaling pathways in various cancers, including prostate cancer. This need is particularly significant in prostate cancer. While androgen deprivation therapy (ADT) has demonstrated promising efficacy in prostate cancer, its long-term use can eventually lead to the development of castration-resistant prostate cancer (CRPC) and neuroendocrine prostate cancer (NEPC). Notably, p300 has been identified as an important co-activator of the androgen receptor (AR), highlighting its significance in prostate cancer progression. Moreover, recent studies have revealed the involvement of p300 in AR-independent oncogenes associated with NEPC. Therefore, the blockade of p300 may emerge as an effective therapeutic strategy to address the challenges posed by both CRPC and NEPC. METHODS: We employed AI-assisted design to develop a peptide-based PROTAC (proteolysis-targeting chimera) drug that targets p300, effectively degrading p300 in vitro and in vivo utilizing nano-selenium as a peptide drug delivery system. FINDINGS: Our p300-targeting peptide PROTAC drug demonstrated effective p300 degradation and cancer cell-killing capabilities in both CRPC, AR-negative, and NEPC cells. This study demonstrated the efficacy of a p300-targeting drug in NEPC cells. In both AR-positive and AR-negative mouse models, the p300 PROTAC drug showed potent p300 degradation and tumor suppression. INTERPRETATION: The design of peptide PROTAC drug targeting p300 is feasible and represents an efficient therapeutic strategy for CRPC, AR-negative prostate cancer, and NEPC. FUNDING: The funding details can be found in the Acknowledgements section.

A Top-Down Design Approach for Generating a Peptide PROTAC Drug Targeting Androgen Receptor for Androgenetic Alopecia Therapy.

While large-scale artificial intelligence (AI) models for protein structure prediction and design are advancing rapidly, the translation of deep learning models for practical macromolecular drug development remains limited. This investigation aims to bridge this gap by combining cutting-edge methodologies to create a novel peptide-based PROTAC drug development paradigm. Using ProteinMPNN and RFdiffusion, we identified binding peptides for androgen receptor (AR) and Von Hippel-Lindau (VHL), followed by computational modeling with Alphafold2-multimer and ZDOCK to predict spatial interrelationships. Experimental validation confirmed the designed peptide's binding ability to AR and VHL. Transdermal microneedle patching technology was seamlessly integrated for the peptide PROTAC drug delivery in androgenic alopecia treatment. In summary, our approach provides a generic method for generating peptide PROTACs and offers a practical application for designing potential therapeutic drugs for androgenetic alopecia. This showcases the potential of interdisciplinary approaches in advancing drug development and personalized medicine.

Development of a Double-Stapled Peptide Stabilizing Both α-Helix and ß-Sheet Structures for Degrading Transcription Factor AR-V7.

Peptide drugs offer distinct advantages in therapeutics; however, their limited stability and membrane penetration abilities hinder their widespread application. One strategy to overcome these challenges is the hydrocarbon peptide stapling technique, which addresses issues such as poor conformational stability, weak proteolytic resistance, and limited membrane permeability. Nonetheless, while peptide stapling has successfully stabilized α-helical peptides, it has shown limited applicability for most ß-sheet peptide motifs. In this study, we present the design of a novel double-stapled peptide capable of simultaneously stabilizing both α-helix and ß-sheet structures. Our designed double-stapled peptide, named DSARTC, specifically targets the androgen receptor (AR) DNA binding domain and MDM2 as E3 ligase. Serving as a peptide-based PROTAC (proteolysis-targeting chimera), DSARTC exhibits the ability to degrade both the full-length AR and AR-V7. Molecular dynamics simulations and circular dichroism analysis validate the successful constraint of both secondary structures, demonstrating that DSARTC is a "first-in-class" heterogeneous-conformational double-stapled peptide drug candidate. Compared to its linear counterpart, DSARTC displays enhanced stability and an improved cell penetration ability. In an enzalutamide-resistant prostate cancer animal model, DSARTC effectively inhibits tumor growth and reduces the levels of both AR and AR-V7 proteins. These results highlight the potential of DSARTC as a more potent and specific peptide PROTAC for AR-V7. Furthermore, our findings provide a promising strategy for expanding the design of staple peptide-based PROTAC drugs, targeting a wide range of "undruggable" transcription factors.

Melatonin suppresses Akt/mTOR/S6K activity, induces cell apoptosis, and synergistically inhibits cell growth with sunitinib in renal carcinoma cells via reversing Warburg effect.

BACKGROUND: Metabolic alteration drives renal cell carcinoma (RCC) development, while the impact of melatonin (MLT), a neurohormone secreted during darkness, on RCC cell growth and underlying mechanisms remains unclear. METHODS: We detected concentration of metabolites through metabolomic analyses using UPLC-MS/MS, and the oxygen consumption rate was determined using the Seahorse Extracellular Flux analyzer. RESULTS: We observed that MLT effectively inhibited RCC cell growth both in vitro and in vivo. Additionally, MLT increased ROS levels, suppressed antioxidant enzyme activity, and induced apoptosis. Furthermore, MLT treatment upregulated key TCA cycle metabolites while reducing aerobic glycolysis products, leading to higher oxygen consumption rate, ATP production, and membrane potential. Moreover, MLT treatment suppressed phosphorylation of Akt, mTOR, and p70 S6 Kinase as well as the expression of HIF-1α/VEGFA in RCC cells; these effects were reversed by NAC (ROS inhibitors). Conversely, MLT synergistically inhibited cell growth with sunitinib and counteracted the Warburg effect induced by sunitinib in RCC cells. CONCLUSIONS: In conclusion, our results indicate that MLT treatment reverses the Warburg effect and promotes intracellular ROS production, which leads to the suppression of Akt/mTOR/S6K signaling pathway, induction of cell apoptosis, and synergistically inhibition of cell growth with sunitinib in RCC cells. Overall, this study provides new insights into the mechanisms underlying anti-tumor effect of MLT in RCC cells, and suggests that MLT might be a promising therapeutic for RCC.

De Novo Design of an Androgen Receptor DNA Binding Domain-Targeted peptide PROTAC for Prostate Cancer Therapy.

Androgen receptor splice variant-7 (AR-V7), one of the major driving factors, is the most attractive drug target in castration-resistant prostate cancer (CRPC). Currently, no available drugs efficiently target AR-V7 in clinical practice. The DNA binding domain (DBD) is indispensable for the transcriptional activity of AR full length and AR splice variants, including AR-V7. Based on the homodimerization structure of the AR DBD, a novel peptide-based proteolysis-targeting chimera (PROTAC) drug is designed to induce AR and AR-V7 degradation in a DBD and MDM2-dependent manner, without showing any activity on other hormone receptors. To overcome the short half-life and poor cell penetrability of peptide PROTAC drugs, an ultrasmall gold (Au)-peptide complex platform to deliver the AR DBD PROTAC in vivo is developed. The obtained Au-AR pep-PROTAC effectively degrades AR and AR-V7 in prostate cancer cell lines, particularly in CWR22Rv1 cells with DC50 values 48.8 and 79.2 nM, respectively. Au-AR pep-PROTAC results in suppression of AR levels and induces tumor regression in both enzalutamide sensitive and resistant prostate cancer animal models. Further optimization of the Au-AR pep-PROTAC can ultimately lead to a new therapy for AR-V7-positive CRPC.

PSA nadir and time to PSA nadir during initial androgen deprivation therapy as prognostic factors in metastatic castration-resistance prostate cancer patients treated with docetaxel.

Prostate-specific antigen nadir (nPSA) and time to nPSA (TTN) have been proved to be associated with the prognosis of prostate cancer. In this study, we explored the prognosis effect of nPSA and TTN during initial androgen deprivation therapy (ADT) in patients with metastatic castration-resistant prostate cancer (mCRPC) after treatment with docetaxel-based chemotherapy. The data of 153 mCRPC patients received docetaxel followed by ADT were retrospectively reviewed. Multivariate Cox regression analysis demonstrated that TTN (overall survival (OS): Hazard ratio [HR] 0.096, 95% confidence interval [CI] 0.045-0.206, p < .001; progression-free survival (PFS): HR 0.128, 95% CI 0.078-0.211, p < .001) and nPSA (OS: HR 2.849, 95% CI 1.318-6.157, p = .008; PFS: HR 1.573, 95% CI 1.008-2.454, p = .046) acted as independent predictors of chemotherapy prognosis. Kaplan-Meier analysis showed that patients with nPSA ≥ 0.2 ng/ml or TTN < 6.5 months had shorter OS and PFS. These results suggest that TTN and nPSA during ADT can affect the prognosis of docetaxel-based chemotherapy prognosis post-castration resistance in patients with mCRPC, and higher nPSA and shorter TTN lead to poor chemotherapy prognosis. What is more, TTN has a greater impact during ADT on the prognosis of chemotherapy than nPSA.