Microsatellite instability (MSI) is a relatively common feature associated with multiple types of cancer, most frequently observed in colorectal, gastric, ovarian, and endometrial tumors [1]. Compared with microsatellite stable (MSS) tumors originating from the same tissue, MSI tumors have better prognosis and reduced likelihood of metastasis. However, studies have found that MSI cancers have a poorer response to current chemotherapy regimens [2,3]. The WRN helicase is considered a novel therapeutic target for MSI cancers, and WRN is a member of the RecQ helicase family [[4], [5], [6]]. Chan et al. discovered through experimental research that the RecQ DNA helicase WRN is selectively essential in both in vitro and in vivo models of MSI. In the MSI model, WRN is required for DNA replication through specific highly expanded microsatellite repeat sequences, and depletion of WRN results in cell cycle arrest, apoptosis, and induction of double-strand DNA breaks. As an MSI-dependent biomarker, it has an advantage over other strong biomarkers [7,8].

The research has found that the program cell death-1 (PD-1) immune checkpoint inhibitor exhibits favorable performance in colorectal cancer with high microsatellite instability (MSI) expression [9]. However, PD-1 blockade is currently not recommended as a frontline treatment option for MSI-high colorectal cancer. Targeting the small molecule inhibitor of WRN may prove to be a promising strategy for treating MSI-high expression in colorectal cancer. Increasing evidence suggests that combining traditional Chinese medicine (TCM) with anti-cancer therapy not only suppresses tumor growth, but also reduces drug resistance, improves adverse reactions, and enhances patient quality of life [10]. In recent years, targeted agents such as CTLA-4, PD-1, and PD-L1 immune checkpoint inhibitors have increased survival rates and overall survival periods in cancer patients [11]. The mechanism of combating tumors by restoring the immune capacity of cancer patients is consistent with the concept of "strengthening vital Qi to treat cancer" in traditional Chinese medicine theory [12]. Combining Bisdemethoxycurcumin with α-PD-L1 antibody can enhance immune response against bladder cancer [13], while Radix Puerariae Lobatae combined with Fructus Scutellariae can reshape the gut microbiome and tumor microenvironment, enhancing the effect of PD-1 blockade on microsatellite stability in colorectal cancer [14]. The compound injection of compound Kushen injection relieves tumor-associated macrophage-mediated immune suppression through TNFR1 and increases the sensitivity of hepatocellular carcinoma to sorafenib [15]. These studies suggest that the combination of traditional Chinese medicine and targeted drugs has significant therapeutic effects in treating tumors, providing new ideas for anti-tumor therapy using TCM compounds. In fact, in the past few decades, an increasing number of researchers have turned their attention to natural compounds with the aim of identifying new bioactive compounds to combat various diseases including cancer [16]. Therefore, the discovery of natural compound molecules that can inhibit WRN protein at the molecular level is of great significance.

In this study, we employed a structure-based virtual screening approach to screen bioactive molecules derived from natural products to identify potential inhibitors against the WRN target. To enhance accuracy, we applied the current academic and industrial TI high-precision binding energy calculation method during the screening process [17]. Moreover, we have demonstrated the binding efficacy of the natural product hits with WRN, as well as their inhibitory effects on the protein, through the employment of molecular dynamics simulation techniques, thereby further elucidating the activity potential of these molecules.