MOTIVATION: Identifying synergistic drug combinations holds promise for more effective treatment strategies. Recent deep learning methods such as Transformers and Graph Neural Networks have shown improved predictive performance, but most of them integrate drug and cell line representations without explicitly modelling the causal effects of genes in mediating drug responses. RESULTS: We introduce CADS (Causal Adjustment for Drug Synergy), a deep learning framework that explicitly models the gene-drug causal relationships to improve both prediction accuracy and biological interpretability. CADS integrates multi-omics data with a learnable gene-selection mechanism that performs causal backdoor adjustment, enabling both drug synergy prediction and causal gene discovery. Across multiple benchmark datasets, CADS consistently achieves superior performance compared with state-of-the-art drug synergy prediction models. In addition, downstream analyses on case studies demonstrate that the inferred gene causal scores can recover clinically validated cancer-related genes involved in drug combinations. These results demonstrate that explicitly modelling causal genetic effects can enhance the reliability and interpretability of drug synergy prediction. AVAILABILITY AND IMPLEMENTATION: The source code of CADS can be found at https://github.com/HuaiwuZhang/causalDC.

MOTIVATION: Understanding how small molecules modulate cellular states remains a critical challenge in drug discovery. The advent of perturbation transcriptomics offers new avenues for elucidating drug-target interactions by capturing cellular transcriptional responses to perturbations. RESULTS: In this study, we propose BioHSNet, a biological function-guided hypergraph siamese network for inferring drug-target interactions from perturbation transcriptomics. BioHSNet utilizes hyperedge representations of functionally grouped gene expression to capture higher-order functional relationships, and integrates compound structural information into the model to bridge chemical structure and functional response. Experimental results demonstrate that BioHSNet outperforms other transcriptome-based methods on the Broad Institute's L1000 datasets, particularly in cold start scenarios. The case study further demonstrates its practical utility for target prediction and drug screening. AVAILABILITY AND IMPLEMENTATION: The source code is available at https://github.com/Zxinyizhang/BioHSNet.

Drug repositioning, a promising strategy in drug development, aims to identify new indications for existing drugs while reducing costs and safety risks. Leveraging their unique advantages in modeling higher-order relations among nodes, hypergraphs and hypergraph neural networks (HGNN) have become increasingly popular in drug repositioning. However, most HGNN-based methods overlook the diverse relations generated during the convolution and do not explicitly model high-order interactions, limiting their ability to capture high-order interaction information adequately. To address these limitations, we propose HGCNDR, a hypergraph convolutional network with explicit high-order interaction extraction for drug repositioning. HGCNDR introduces a relation-aware hypergraph convolution operation to handle distinct relation types and a Hadamard product-based strategy to effectively model high-order interactions among drugs and diseases, efficiently extracting the resulting high-order interaction information. Specifically, HGCNDR constructs two feature graphs and a hypergraph based on drug similarity features, disease similarity features, and drug-disease association networks. HGCNDR then employs graph convolutional networks to extract embeddings from the feature graphs, while using the relation-aware hypergraph convolution operation and the strategy to extract structural and high-order interaction information embeddings from the hypergraph. Additionally, to preserve the common semantics between the embeddings extracted from the feature graphs and the hypergraph, HGCNDR introduces a consistency constraint. The experimental results demonstrate that HGCNDR has competitive performance compared to several baseline methods. Moreover, case studies on Alzheimer's disease and Breast carcinoma confirm that HGCNDR can retrieve more actual drug-disease associations in the top prediction results.

Drug repositioning greatly reduces drug development costs and time by discovering new indications for existing drugs. With the development of technology and large-scale biological databases, computational drug repositioning has increasingly attracted remarkable attention, which can narrow down repositioning candidates. Recently, graph neural networks (GNNs) have been widely used and achieved promising results in drug repositioning. However, the existing GNNs based methods usually focus on modeling the complex drug-disease association graph, but ignore the semantic information on the graph, which may lead to a lack of consistency of global topology information and local semantic information for the learned features. To alleviate the above challenge, we propose a novel drug repositioning model based on graph contrastive learning, termed DRGCL. First, we treat the known drug-disease associations as the topology graph. Second, we select the top- similar neighbor from drug/disease similarity information to construct the semantic graph rather than use the traditional data augmentation strategy, thereby maximally retaining rich semantic information. Finally, we pull closer to embedding consistency of the different embedding spaces by graph contrastive learning to enhance the topology and semantic feature on the graph. We have evaluated DRGCL on four benchmark datasets and the experiment results show that the proposed DRGCL is superior to the state-of-the-art methods. Especially, the average result of DRGCL is 11.92% higher than that of the second-best method in terms of AUPRC. The case studies further demonstrate the reliability of DRGCL.

Cell clustering is vital for studying cellular heterogeneity and understanding biological mechanisms. With the advancement of sequencing technologies, it is now possible to obtain multiomics data from single cells, such as ATAC-seq and RNA-seq. Compared to single-omics data, multiomics data offer a more comprehensive view of the cellular landscape. Although several single-cell multiomics clustering methods have been developed, the sparsity and complexity of multiomics data make clustering a challenging computational task. This paper proposes a single cell multiomics clustering method called scGDCC, which is based on graph neural networks and dual contrastive calibration. scGDCC utilizes graph neural networks to capture the neighborhood information of cells and employs dual contrastive calibration to achieve more consistent joint representations of cells. Experiments on five dual-omics datasets (ATAC-seq and RNA-seq) and two triple-omics datasets (ATAC-seq, RNA-seq, and protein) demonstrate the superiority of this clustering method. Additionally, visualization experiments further validate the effectiveness of the joint cellular representations.

MOTIVATION: Drug repositioning is an effective strategy to identify new indications for existing drugs, providing the quickest possible transition from bench to bedside. With the rapid development of deep learning, graph convolutional networks (GCNs) have been widely adopted for drug repositioning tasks. However, prior GCNs based methods exist limitations in deeply integrating node features and topological structures, which may hinder the capability of GCNs. RESULTS: In this study, we propose an adaptive GCNs approach, termed AdaDR, for drug repositioning by deeply integrating node features and topological structures. Distinct from conventional graph convolution networks, AdaDR models interactive information between them with adaptive graph convolution operation, which enhances the expression of model. Concretely, AdaDR simultaneously extracts embeddings from node features and topological structures and then uses the attention mechanism to learn adaptive importance weights of the embeddings. Experimental results show that AdaDR achieves better performance than multiple baselines for drug repositioning. Moreover, in the case study, exploratory analyses are offered for finding novel drug-disease associations. AVAILABILITY AND IMPLEMENTATION: The soure code of AdaDR is available at: https://github.com/xinliangSun/AdaDR.

Drug repositioning identifies novel therapeutic potentials for existing drugs and is considered an attractive approach due to the opportunity for reduced development timelines and overall costs. Prior computational methods usually learned a drug's representation from an entire graph of drug-disease associations. Therefore, the representation of learned drugs representation are static and agnostic to various diseases. However, for different diseases, a drug's mechanism of actions (MoAs) are different. The relevant context information should be differentiated for the same drug to target different diseases. Computational methods are thus required to learn different representations corresponding to different drug-disease associations for the given drug. In view of this, we propose an end-to-end partner-specific drug repositioning approach based on graph convolutional network, named PSGCN. PSGCN firstly extracts specific context information around drug-disease pairs from an entire graph of drug-disease associations. Then, it implements a graph convolutional network on the extracted graph to learn partner-specific graph representation. As the different layers of graph convolutional network contribute differently to the representation of the partner-specific graph, we design a layer self-attention mechanism to capture multi-scale layer information. Finally, PSGCN utilizes sortpool strategy to obtain the partner-specific graph embedding and formulates a drug-disease association prediction as a graph classification task. A fully-connected module is established to classify the partner-specific graph representations. The experiments on three benchmark datasets prove that the representation learning of partner-specific graph can lead to superior performances over state-of-the-art methods. In particular, case studies on small cell lung cancer and breast carcinoma confirmed that PSGCN is able to retrieve more actual drug-disease associations in the top prediction results. Moreover, in comparison with other static approaches, PSGCN can partly distinguish the different disease context information for the given drug.