Life

The SARS-CoV-2 papain-like protease (PL^pro) is an essential viral enzyme that promotes viral polyprotein processing while simultaneously suppressing the host innate immune response, which makes it a primary target for developing antiviral drugs. The present study employs a comprehensive approach integrating untargeted metabolomic profiling, in silico molecular docking and dynamics simulations, Molecular Mechanics Generalized Born Surface Area (MM-GBSA) energetic assessments, and biochemical enzyme assays. This integrated method aims to discover natural PL^pro inhibitors from two ethnomedicinal plants, Lippia javanica and Acorus calamus, which have long been utilized in African traditional medicine to treat respiratory diseases. Comprehensive metabolite profiling using untargeted Ultra-Performance Liquid Chromatography–Tandem Mass Spectrometry (UPLC-MS/MS) and Global Natural Products Social (GNPS) molecular networking revealed flavonoid glucuronides and phenylpropanoid derivatives as the major constituents in both plant species. In situ histochemical staining further offered spatial validation of phenolic- and lignin-associated tissues, supporting the phenolic-dominated molecular families detected by GNPS molecular networking. In silico evaluation of six selected compounds demonstrated spontaneous and thermodynamically favorable binding to PL^pro, with ΔG_bind values ranging from −5.63 to −6.43 kcal/mol. Catechin-7-glucoside emerged as the lead compound, establishing multiple hydrogen bond networks with Asp164, Gln269, Tyr264, and Asn267, supplemented by hydrophobic engagement with Pro247 and Pro248, and π-π stacking with the blocking loop 2 (BL2 loop). Molecular dynamics simulations confirmed the stability of the protein–ligand complexes. Biochemical enzyme assays confirmed concentration-dependent inhibition of PL^pro proteolytic and deubiquitinating activity by both crude plant extracts and isolated bioactive compounds. However, S-adenosyl-methionine showed comparatively high PL^pro proteolytic activity (IC₅₀ 5.872 µM) compared to catechin-7-glucoside, with an IC₅₀ of 7.493 µM, exhibiting efficacy similar to the reference inhibitor GRL0617. Both the extracts of L. javanica and A. calamus have shown significant inhibitory activity while maintaining cell viability in Human embryonic kidney 293T cell (HEK293T) culture models, indicating a favorable safety profile of the tested concentrations. Based on these results, catechin-based polyphenols and phenylpropanoid derivatives appear as promising lead compounds for the development of PL^pro inhibitors. To progress toward therapeutic use, further work is necessary in pharmacokinetics, structural optimization, and antiviral validation in cell models.

Stemness is a critical factor in tumor initiation, progression, metastasis, and resistance to treatment. The AXL receptor and hedgehog (Hh) signaling pathways play significant roles in regulating stemness, making them potential therapeutic targets. This study explores the involvement of AXL and hedgehog signaling in maintaining stemness and contributing to trastuzumab resistance in HER2-positive breast cancer. The expression of AXL and Hh markers was assessed in trastuzumab-resistant SKBR3 and HCC1954 cell lines and their parental counterparts. Trastuzumab resistance was associated with upregulation of AXL expression, with the GAS6/AXL axis identified as a regulator of stemness. Although inhibition of hedgehog signaling using GANT61 did not affect AXL expression, overexpression of AXL led to increased levels of hedgehog markers (e.g., Gli1, Ptch1) and stemness markers (e.g., Sox2, Oct4, Nanog), while silencing AXL resulted in their downregulation. Furthermore, AXL overexpression enhanced stemness in resistant cells, suggesting its role in resistance mechanisms. The combination of AXL inhibition and trastuzumab treatment significantly reduced stemness and hedgehog marker expression, indicating a synergistic effect. These results emphasize the pivotal role of AXL in regulating both stemness and hedgehog signaling in HER2-positive breast cancer. The study suggests that targeting both AXL and HER2 could be a promising strategy to overcome trastuzumab resistance and improve treatment outcomes.

Campanacci grade III giant cell tumors of the distal radius frequently require en bloc resection to achieve adequate oncologic control. Reconstruction of the resulting defect remains challenging, particularly with respect to preservation of distal radioulnar joint stability and forearm rotation. Although proximal fibular autograft reconstruction is well established, ligamentous stabilization of the distal radioulnar joint is rarely incorporated in oncologic settings. This technical note describes an integrated reconstructive strategy combining proximal fibular autograft with distal oblique bundle reconstruction, illustrated by a representative clinical case. The technique involves segmental en bloc resection of the distal radius followed by reconstruction using an ipsilateral, nonvascularized proximal fibular autograft including the fibular head. Distal radioulnar joint stability is addressed through reconstruction of the distal oblique bundle using an autologous palmaris longus tendon graft. Surgical indications, operative steps, donor site stabilization, and perioperative management are detailed. Functional evolution was assessed using the Musculoskeletal Tumor Society scoring system and range-of-motion measurements. Histopathological examination confirmed negative oncologic margins. Early postoperative events included donor-site common peroneal nerve dysfunction and radiocarpal instability requiring temporary Kirschner wire stabilization. At nine months, the Musculoskeletal Tumor Society score reached 80%, with forearm rotation preserved at 68.8% pronation and 81.3% supination of normal values. Combined osseous and ligamentous reconstruction following distal radius resection is technically feasible and may allow preservation of distal forearm mechanics while maintaining oncologic principles. Broader validation will require application in larger clinical series and longer follow-up.