Pharmacological modulation of RB1 activity mitigates resistance to neoadjuvant chemotherapy in locally advanced rectal cancer

Ligustrazine nano-drug delivery system ameliorates doxorubicin-mediated myocardial injury via piezo-type mechanosensitive ion channel component 1-prohibitin 2-mediated mitochondrial quality surveillance

BACKGROUND

Doxorubicin (DOX) demonstrates significant therapeutic and anticancer efficacy. Nevertheless, it demonstrates significant cardiotoxicity, resulting in permanent cardiac damage. Ligustrazine (LIG) is a bioactive alkaloid derived from the rhizome of the medicinal plant Ligusticum chuanxiong Hort. The alkaloid has exhibited cardioprotective properties. The therapeutic application of LIG is constrained by inadequate water solubility, fast breakdown, and low bioavailability. Nanoparticle drug delivery technologies effectively address these constraints by encapsulating LIG into nanocarriers, significantly enhancing its solubility and bioavailability, hence maximizing its therapeutic efficacy. Consequently, this study employed tetrahedral backbone nucleic acid molecules as LIG carriers. Furthermore, animal models and single-cell sequencing analyses were employed to forecast the mechanisms and targets of pertinent studies. A mouse model genetically modified for the piezo type mechanosensitive ion channel component 1 (PIEZO1), transmembrane BAX inhibitor motif containing 6 (TMBIM6), and prohibitin 2 (PHB2), along with an in vivo and in vitro model of DOX-induced cardiomyopathy (DIC), was established, and a gene-modified cellular system comprising upstream genes and downstream effector targets was constructed. The mechanism of LIG was validated by molecular biology and integrated pharmacology with the implementation of the LIG nano-drug loading method.

RESULTS

LIG nano-delivery enhanced DOX-induced cardiac dysfunction and mitochondrial impairment by modulating the PHB2Ser91/Ser176 phosphorylation axis through PIEZO1-TMBIM6, and significantly suppressed cardiomyocyte pyroptosis resulting from mitochondrial homeostasis dysregulation. The findings indicate that LIG nano-delivery is a promising therapeutic approach for addressing DIC.

CONCLUSION

The PHB2Ser91/Ser176 phosphorylation axis regulated by PIEZO1-TMBIM6 is an important target for LIG nano-drug delivery systems to improve mitochondrial damage in DIC.

Novel technetium-99m-labelled ribociclib isocyanide derivatives for imaging cyclin-dependent kinase 4/6 (CDK4/6) expression in cancer

Cyclin-dependent kinase 4/6 (CDK4/6) plays a crucial role in cell cycle regulation, is overexpressed in various cancers and is an important target in the development of radiotracers for tumour imaging. Despite the increasing recognition of CDK4/6 inhibitors in cancer therapy, their application is limited by the lack of suitable biomarkers. Herein, we developed a series of technetium-99m-labelled CDK4/6 radiotracers and utilized a linker optimization strategy to reduce their abdominal uptake and enhance their imaging properties. By introducing polyethylene glycol chains (PEGn, n = 2, 3, or 4) of different lengths, we successfully prepared the first technetium-99m-labelled ribociclib isocyanide derivatives via a one-step method. After rapid screening, we selected [99mTc]Tc-RIB-PEG4-CN (LogD7.4 = 0.01 ± 0.01) because of its superior uptake in the cell lines and suitable nontarget uptake in vivo. Additionally, it displayed nanomolar affinity (5.887 ± 0.3579 nM). In HCT116 xenograft models, the probe exhibited significant tumour uptake (2.44 ± 0.29 % ID/g at 4 h p.i.) while maintaining reduced abdominal uptake. Moreover, the probe showed specificity in HCT116 xenograft models, as evidenced by a 49.2 % decrease in the tumour-to-muscle ratio in the presence of excess ribociclib for blocking. Micro-SPECT/CT images of HCT116 and MCF-7 xenografts revealed the liver metabolism of [99mTc]Tc-RIB-PEG4-CN, with robust tumour retention and comparatively low abdominal uptake at 4 h p.i. This novel radiotracer enables the noninvasive evaluation of CDK4/6 expression, providing valuable insights for clinical treatment strategies and further mechanistic studies.

Untangling the Role of MYC in Sarcomas and Its Potential as a Promising Therapeutic Target

MYC plays a pivotal role in the biology of various sarcoma subtypes, acting as a key regulator of tumor growth, proliferation, and metabolic reprogramming. This oncogene is frequently dysregulated across different sarcomas, where its expression is closely intertwined with the molecular features unique to each subtype. MYC interacts with critical pathways such as cell cycle regulation, apoptosis, and angiogenesis, amplifying tumor aggressiveness and resistance to standard therapies. Furthermore, MYC influences the tumor microenvironment by modulating cell-extracellular matrix interactions and immune evasion mechanisms, further complicating therapeutic management. Despite its well-established centrality in sarcoma pathogenesis, targeting MYC directly remains challenging due to its "undruggable" protein structure. However, emerging therapeutic strategies, including indirect MYC inhibition via epigenetic modulators, transcriptional machinery disruptors, and metabolic pathway inhibitors, offer new hope for sarcoma treatment. This review underscores the importance of understanding the intricate roles of MYC across sarcoma subtypes to guide the development of effective targeted therapies. Given MYC's central role in tumorigenesis and progression, innovative approaches aiming at MYC inhibition could transform the therapeutic landscape for sarcoma patients, providing a much-needed avenue to overcome therapeutic resistance and improve clinical outcomes.

4'-Demethylpodophyllotoxin functions as a mechanism-driven therapy by targeting the PI3K-AKT pathway in Colorectal cancer

The treatment of colorectal cancer (CRC) poses significant challenges in terms of drug resistance and poor prognosis, necessitating the exploration of effective therapeutic strategies. In this study, high-throughput drug screening was utilized to identify Chinese herbal medicines with notable therapeutic effects on CRC. Among the compounds identified, 4'-demethylpodophyllotoxin (DOP), a derivative of podophyllotoxin, emerged as a potent anti-cancer compound. DOP exhibited time- and dose-dependent growth inhibition on CRC cell lines and tumor organoids derived from patients. RNA-seq revealed that DOP activated the PI3K-AKT pathway, leading to tumor cell apoptosis and cell cycle arrest at the G2/M phase. Additionally, DOP induced DNA damage in CRC cells. To further validate its therapeutic efficacy in CRC, the DLD1-derived xenograft model demonstrated that DOP effectively suppressed CRC growth in vivo. In conclusion, these findings highlight the significant therapeutic potential of DOP as an anti-tumor drug for treating CRC, thereby opening new avenues for investigating Podophyllotoxin derivatives in this specific field.

HDAC-driven mechanisms in anticancer resistance: epigenetics and beyond

The emergence of drug resistance leading to cancer recurrence is one of the challenges in the treatment of cancer patients. Several mechanisms can lead to drug resistance, including epigenetic changes. Histone deacetylases (HDACs) play a key role in chromatin regulation through epigenetic mechanisms and are also involved in drug resistance. The control of histone acetylation and the accessibility of regulatory DNA sequences such as promoters, enhancers, and super-enhancers are known mechanisms by which HDACs influence gene expression. Other targets of HDACs that are not histones can also contribute to resistance. This review describes the contribution of HDACs to the mechanisms that, in some cases, may determine resistance to chemotherapy or other cancer treatments.

A role for Retinoblastoma 1 in hindbrain morphogenesis by regulating GBX family

The hindbrain, which develops from the anterior end of the neural tube expansion, can differentiate into the metencephalon and myelencephalon, with varying sizes and functions. The midbrain-hindbrain boundary (MHB) and hindbrain myelencephalon/ventral midline (HMVM) are known to be the source of the progenitors for the anterior hindbrain and myelencephalon, respectively. However, the molecular networks regulating hindbrain morphogenesis in these structures remain unclear. In this study, we show that retinoblastoma 1 (rb1) is highly expressed at the MHB and HMVM in zebrafish. Knocking out rb1 in mice and zebrafish results in an enlarged hindbrain due to hindbrain neuronal hyperproliferation. Further study reveals that Rb1 controls the hindbrain morphogenesis by suppressing the expression of Gbx1/Gbx2, essential transcription factors for hindbrain development, through its binding to E2f3/Hdac1, respectively. Interestingly, we find that Gbx1 and Gbx2 are expressed in different types of hindbrain neurons, suggesting distinct roles in hindbrain morphogenesis. In summary, our study clarifies the specific role of RB1 in hindbrain neural cell proliferation and morphogenesis by regulating the E2f3-Gbx1 axis and the Hdac1-Gbx2 axis. These findings provide a research paradigm for exploring the differential proliferation of neurons in various brain regions.