Alzheimer's disease (AD) and cancer are both age-related conditions, yet numerous large-scale epidemiological studies have consistently documented an inverse association, with individuals diagnosed with cancer exhibiting a reduced risk of AD and vice versa. Although this relationship has been replicated across diverse populations, its biological basis remains poorly understood. To address this gap, the present study applies a framework that integrates locus-level genetic correlation (rg) with genetically regulated gene expression to clarify the molecular factors contributing to the inverse epidemiological patterns observed between the two diseases. We used the largest available genome-wide association studies (GWAS) (Nmax = 448,150) to quantify local genetic correlations between AD and several age-associated cancers, including breast, prostate, lung, colorectal, melanoma, basal cell carcinoma, bladder, and endometrial cancer. Eight genomic regions showed significant negative local rg, at the 19q13.31-19q13.32 locus demonstrating strong negative correlations across multiple cancers, including breast, prostate, lung, melanoma, and endometrial cancer. To evaluate the contribution of genetically regulated gene expression, we conducted transcriptome-wide association studies (TWAS) using precomputed gene expression weights from cancer tissues (The Cancer Genome Atlas-TCGA), disease-agnostic tissues (Genotype-Tissue Expression-GTEx), and brain tissue (dorsolateral prefrontal cortex-DLPFC). For each AD-cancer pair, we prioritized genes that were nominally significant in both traits (p < 0.05) and exhibited inverse TWAS Z scores. This analysis identified 24 genes with opposite effect directions between AD and at least three cancer types. TWAS signals also aligned with local rg findings at the 19q13.31-19q13.32 region, suggesting that regulatory variation near this locus contributes to shared but opposing genetic effects beyond the canonical APOE signal. Across cancer types, genes inversely associated with AD converged on pathways involved in cell cycle regulation, apoptosis, DNA-damage response, and metabolic processes. These results support the hypothesis that biological mechanisms promoting proliferation and survival in cancer may oppose those contributing to neurodegeneration in AD.

Melanoma is an aggressive skin cancer with high metastatic potential and poor long-term survival, highlighting the need for new therapeutic targets. Although microRNAs are critical regulators of tumor progression, the function of miR-374b-5p in melanoma remains poorly understood. Here, we identify miR-374b-5p as a tumor suppressor in melanoma cells. We show that miR-374b-5p directly targets vascular endothelial growth factor C (Vegfc) and is associated with changes in mitogen-activated protein kinase (MAPK) signaling, accompanied by reduced levels of phosphorylated extracellular signal-regulated kinase (pERK) and tyrosinase (TYR). Consistent with these observations, miR-374b-5p overexpression suppresses melanoma cell proliferation, migration, and invasion in vitro. Conditioned media from miR-374b-5p-overexpressing melanoma cells is also associated with changes in macrophage-related inflammatory markers, suggesting that these alterations are consistent with a shift toward a more pro-inflammatory macrophage phenotype. In a mouse model, miR-374b-5p overexpression significantly reduced tumor growth and angiogenesis, and downregulated the lymphangiogenic factor VEGFC. Together, these findings identify miR-374b-5p as a novel regulator of melanoma progression that acts through VEGFC-associated MAPK signaling and tumor microenvironment reprogramming, identifying miR-374b-5p as a promising therapeutic candidate for melanoma.

Lipids are the major energy reservoir, but excessive fat accumulation drives immune cell trapping, chronic inflammation, autoimmunity, and cancer. Lipid synthesis, secretion, degradation, and the shuttling to cellular organelles and compartments are still poorly investigated in all cell types of the mammalian body. The major routes of FA uptake are dietary uptake, lipolysis, and de novo synthesis. We highlight disease associations zooming in on the Signal Transducer and Activator of Transcription 1/3/5 (STAT1/3/5) molecules in association with cytokine, growth factors, and hormone action, steering lipid metabolism. We compare STAT-lipid crosstalk from nuclear and mitochondrial perspectives, highlighting roles in immunity, metabolic diseases, and cancer, and providing insights into key regulatory mechanisms of lipid metabolism. A high degree of cellular flexibility in metabolic adaptation explains the need for fine-tuning, in which STAT molecules can function as rheostats to maintain energy equilibrium within cellular compartments. This concept bridges, e.g., high-energy flux or the Warburg effect, with the Hydride Transfer Complex upon low-energy provision. Another interesting STAT1/3/5 aspect is their Lipid droplet (LD) association and LD formation. LDs play key roles in disease initiation or progression, including autoimmunity or cancer, as well as chronic inflammatory diseases due to their role in (1) lipotoxicity, (2) cell death regulation, (3) immune system amelioration, and (4) energy provision. Finally, the therapeutic consequences of the angles are outlined, along with future research directions.

Upregulation of glutaminase enzymatic activity promotes tumour cell proliferation. Its overexpression correlates with poor disease outcome in patients, including those with breast cancer. A selective glutaminase inhibitor, CB-839, which targets cancer cells by blocking glutamine conversion to glutamate, has shown promising preclinical results as a therapeutic target in triple-negative breast cancer treatment. The current study aimed to determine the importance of glutaminase in Oestrogen Receptor positive/luminal breast cancer to potentially identify therapeutic targets to treat this subtype. In vitro studies using luminal breast cancer cells were performed to investigate the effects of siRNA knockdown of glutaminase genes (GLS and GLS2) and inhibition using CB-839 on functional assays. Silencing GLS in luminal breast cancer cells significantly reduced cell proliferation whilst inducing apoptosis. A similar impact on cell proliferation was observed when silencing GLS2 in luminal B cells, but there was no observed effect on cell apoptosis and cell cycle. There was little effect of GLS inhibition using CB-839 in luminal breast cancer. This study demonstrates that glutaminase is necessary for luminal breast cancer growth and survival. Co-targeting GLS and GLS2 might be a novel approach for the treatment of this subclass. Further functional studies to evaluate the underlying molecular mechanisms of this process are warranted.

Programmed Death-Ligand 1 (PD-L1) promotes tumor progression through several mechanisms, including its intrinsic effect on breast cancer cell proliferation via the S-Phase Kinase-Associated Protein 2 (SKP2)-p21^Cip1/p27^Kip1 (SKP2-p21/p27) axis. However, the specific regulatory signaling through which PD-L1 influences the SKP2-p21/p27 axis to drive cell proliferation remains unclear. To investigate how PD-L1 mediates SKP2-dependent proliferation, proteomic analyses, gene-expression manipulation via knockdown or overexpression, Western blotting, quantitative immunofluorescence, colony-forming assays, real-time cell analysis, and Xenograft-derived cells were used. Proteomic data analysis identified several PD-L1 downstream targets as potential candidate regulators of the SKP2-p21/p27 axis and activators of the PI3K/AKT pathway. Candidate screening by gene knockdown, followed by analyses of SKP2, p21, and p27 protein expression, revealed Livin and Galectin-1 as upstream regulators of the SKP2-p21/p27 axis. Moreover, Western blotting and quantitative immunofluorescence in three breast cancer cell lines confirmed that PD-L1 is an upstream regulator of Livin, Galectin-1, and SKP2 protein expression. Mechanistically, Livin and Galectin-1 enhanced AKT phosphorylation (Ser473) to sustain PI3K/AKT pathway activation in a positive feedback loop to upregulate SKP2 expression. Functional assays, including colony-forming assays and real-time cell analyzer, demonstrated that Livin and Galectin-1 are critical for PD-L1-mediated, SKP2-dependent proliferation. These findings were corroborated in vivo using xenograft-derived cells. Overall, these findings delineate a tumor-intrinsic signaling axis in which PD-L1 upregulates Livin and Galectin-1 to sustain PI3K/AKT activity and drive SKP2-dependent cell proliferation. Targeting Livin and/or Galectin-1 may provide a rational strategy to disrupt PD-L1-associated proliferative signaling and improve combinatorial therapeutic approaches in breast cancer.

Male urological cancers, including clear cell renal cell carcinoma (ccRCC), bladder cancer (BC), and prostate cancer (PCa), are characterized by extensive heterogeneity and complex ecosystems, yet the underlying mechanisms remain incompletely understood. In this study, scRNA-seq, scATAC-seq and spatial transcriptomics data are integrated to systematically characterize the features of the tumor microenvironment (TME). We identify tumor cell subclones and elucidate the impact of chromosomal abnormalities on their characteristic functions. We further identify transcription factor regulatory networks by analyzing tumor cell differentiation trajectories. Importantly, we integrate DNA methylation and SNP information to deeply dissect the tumor cell differentiation process, revealing the multilayer regulatory mechanisms of tumor-related genes. Additionally, we reveal the evolution of cellular states across ecotypes to provide a more comprehensive characterization of TME. Finally, we screened potential therapeutic agents targeting the molecular mechanisms underlying tumor cell differentiation (Amivantamab in ccRCC, Levothyroxine in BC, Ouabain in PCa) and signature genes of ecotype. In conclusion, our work establishes a comprehensive framework for tumor assessment and informs the development of precision therapeutic strategies.

Melanoma is a highly malignant neoplasm of the skin with early metastatic spread and increasing incidence worldwide. Although there are significant therapeutic advances in immunotherapy, especially with the checkpoint inhibitors targeting PD-1 and CTLA-4, challenges such as treatment-related toxicities, a heterogeneous response to therapy, and drug resistance continue to exist. There are unmet needs for novel therapeutic strategies and/or approaches to complement the existing treatment options. Potential targets for future melanoma treatment are the gap junction proteins, connexins, which show an altered pattern of regulation during melanoma progression. In this review, we highlight the regulation of gap junctions during melanoma progression and the characterization of gap junctions as tumor suppressors during early-stage tumor development and then the reversion to enhancers of tumor metastasis during late-stage melanoma progression. We provide a comprehensive overview of gap junctions in the skin and how the connexin proteins, which comprise gap junctions, are alternatively regulated in melanoma progression. Connexins are protein channels in the human body that consist of 21 isoforms. These isoforms form gap junctions that provide important intercellular signaling and permeability channels. Each connexin protein consists of four transmembrane domains and a C-terminal tail, which is an important part of its function and regulation. Permeants of gap junctions include signaling molecules such as cyclic AMP and inositol triphosphate which are linked to key cellular behaviors such as proliferation and migration, making them essential for several tumor-related processes. At least ten connexin isoforms are found in normal skin. Connexin 43 (Cx43) is classified as the most prevalent isoform while Connexin 26 (Cx26) has been reported to be more specialized with restricted expression patterns. Cx43 and Cx26 regulate the growth, differentiation, and repair of the epidermis after injury. Evidence suggests that connexins have a stage-related function in melanoma. Loss of connexin expression and gap junctional intercellular communication is linked to tumor suppression and loss of differentiation in early-stage melanoma, while re-expression or overexpression of specific connexins, notably Cx43, may promote metastasis through enhanced tumor-stromal interactions and increased motility in late-stage melanoma. Such opposing actions of connexins support their candidacy as biomarkers and therapeutic targets. Understanding the dual-stage related functions of connexins in melanoma development and progression may lead to less cytotoxic and more efficient future therapeutic approaches.

Soft tissue sarcomas are rare malignant mesenchymal tumors for which accurate diagnosis, prognostic stratification, and therapeutic decision-making remain challenging. Although histopathology and immunohistochemistry are essential diagnostic tools, they frequently fail to capture the molecular complexity underlying tumor aggressiveness and treatment resistance. In this study, we evaluated the utility of RNA-based next-generation sequencing for the molecular characterization of STS and for elucidating transcriptomic mechanisms associated with aggressive tumor behavior. An observational cohort of 24 patients with histologically confirmed soft tissue sarcomas was analyzed, using adipose and skeletal muscle tissue as controls. RNA was extracted from tumor samples, libraries were prepared with a targeted pan-cancer panel, and sequencing was performed on the Illumina platform, followed by bioinformatic analysis using DRAGEN pipelines and DESeq2. RNA-NGS identified a predominance of single-nucleotide polymorphisms and significant differential gene expression, with overexpression of proliferation-related genes (TOP2A, MKI67, BUB1B), extracellular matrix and microenvironment-associated genes (COL11A1, SPP1), and developmental regulators (HOXD13, MELK). Subgroup analysis revealed a distinct transcriptomic profile in leiomyosarcoma, while gene fusion analysis detected clinically relevant alterations. These findings demonstrate that RNA-NGS provides biologically and clinically meaningful insights into the molecular landscape of soft tissue sarcomas and supports its integration into precision medicine-oriented diagnostic workflows.

Dedifferentiation-the acquisition of an early developmental state-is a hallmark of cancer. However, the underlying mechanisms that lead to cancer-associated dedifferentiation are not fully understood. Transposable elements (TEs) are becoming increasingly recognised as important regulators of development and disease. The recruitment of TE sequences has played an important role in placental evolution, and TE-derived genes play critical roles in placental development. Although important biological differences exist between tumours and the placenta, the placenta shares certain features with tumours, including the capacity to invade surrounding tissue and modulate the maternal immune response. In this regard, TEs have been implicated in cancer development, and are documented to contribute to oncogenesis through multiple different mechanisms. Moreover, cancers reacquire an epigenetic landscape, which is reflective of early development, and which corresponds to increased phenotypic plasticity, including facilitating the activation of early developmental genes. Many cancers can repurpose developmental genes, including TE-associated genes, which may contribute to pathways involved in invasion and metastasis. Determining whether TE activation is a consequence of broader epigenetic reprogramming or actively contributes to dedifferentiation will be important for understanding cancer biology and may facilitate improvements in cancer diagnosis and treatment.

PIWI-interacting RNAs (piRNAs) are a class of small non-coding RNAs initially identified in germline cells as genome guardians that silence transposable elements. Recent studies have expanded this view, revealing that piRNAs and PIWI proteins are broadly expressed in somatic tissues and participate in epigenetic and post-transcriptional gene regulation. This review systematically summarizes piRNA biogenesis and molecular mechanisms, with a focus on their functional diversification from germline to somatic cells. We detail piRNA dysregulation and its association with various human diseases, including cancer, cardiovascular disorders, neurodegenerative diseases, immune dysfunction, and reproductive disorders. By integrating recent findings, this review provides a comprehensive overview of piRNA-mediated regulatory networks and highlights their potential as novel biomarkers and therapeutic targets.