Yan Cheng

ATP6AP1, a key accessory subunit of the vacuolar H⁺-ATPase (V-ATPase) complex responsible for organelle acidification, has emerged as a potential cancer driver. Numerous studies have shown that ATP6AP1 is significantly upregulated in breast cancer, and its high expression is associated with poor prognosis. However, the specific functions and underlying mechanisms of ATP6AP1 in breast cancer progression remain unclear. In the present study, ATP6AP1 was demonstrated to enhance the malignant phenotype of breast cancer cells by upregulating XIAP expression. YY1 was further identified as a novel transcription factor that regulates XIAP, and ATP6AP1 was shown to directly interact with YY1, thereby stabilizing YY1 protein levels and subsequently promoting XIAP expression. In addition, ATP6AP1 silencing markedly increased the sensitivity of breast cancer cells to paclitaxel. Through screening of an FDA-approved drug library, niclosamide was identified as a novel degrader of ATP6AP1. Niclosamide bound to ATP6AP1, reduced its protein stability, and consequently downregulated its expression. Moreover, niclosamide inhibited the proliferation, migration, and invasion of breast cancer cells while promoting apoptosis through targeted degradation of ATP6AP1. Furthermore, niclosamide significantly enhanced the sensitivity of breast cancer cells to paclitaxel by targeting the ATP6AP1-YY1-XIAP axis. Taken together, these findings demonstrated that ATP6AP1 promotes breast cancer progression through activation of the YY1-XIAP signaling axis. Niclosamide was also identified as a promising therapeutic agent targeting ATP6AP1, thereby providing a potential therapeutic strategy for breast cancer treatment.

Background: Triggering tumor cell death still serves as the core and ultimate goal to restrict tumors including colorectal cancer, a highly lethal malignant alimentary canal tumor. Disulfidptosis, a newly defined form of programmed cell death, offers a new potential possibility for anti-tumor purposes. Studies have shown that long non-coding RNAs (lncRNAs) are involved in the regulation of tumor disulfidptosis, however, their role in colorectal cancer is yet poorly defined. In this study, we aim to explore the relationship between lncRNAs and disulfidptosis in colorectal cancer. Methods: We used RNA sequencing data of patients with colon adenocarcinoma (COAD) from The Cancer Genome Atlas (TCGA) to screen disulfidptosis-related lncRNAs via correlation analysis. Univariate, least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression algorithm were performed to identify key disulfidptosis-related lncRNAs and develop prognostic model. After each sample was labelled with risk score, Kaplan-Meier (KM) and receiver operating characteristic (ROC) curve analyses were conducted in both high risk-score and low risk-score groups. Additionally, quantitative polymerase chain reaction (qPCR) was used to assess expression pattern of key disulfidptosis-related lncRNAs in colon cancer cell lines. Cell Counting Kit-8 (CCK-8) assay, cell colony formation assay, cell counting assay were employed to investigate the roles of MALINC1 in colon cancer growth. Deeply, free thiol and glutathione (GSH) content assay and the protein level of disulfidptosis key player SLC7A11 were further implemented to study the relationship between MALINC1 and disulfidptosis. Furthermore, the effect of MALINC1 on the sensitivity of COAD cell lines to platinum-based drugs by CCK-8 assay, cell colony formation assay and cell counting assay. Results: We identified six key disulfidptosis-related lncRNAs, AL354993.2, AP003555.1, MALINC1, AC013652.1, AC074212.1 and AC007128.1. The prognostic model we developed successfully predict survival of patients with COAD. One of the six key disulfidptosis-related lncRNAs, MALINC1, is highly expressed in COAD cell lines HCT8 and SW480. Knockdown of MALINC1 markedly suppressed cell proliferation, reduced intracellular free sulfhydryl groups and GSH, and upregulated SLC7A11. Moreover, MALINC1 knockdown enhanced the sensitivity of these cells to platinum-based drugs. Conclusions: These findings suggest that a prognostic model based on six key disulfidptosis-related lncRNAs holds potential for predicting outcomes in patients with COAD, and that targeting MALINC1 may offer new insights into colorectal cancer chemotherapy.

Triple-negative breast cancer (TNBC), characterized by the absence of effective therapeutic targets, remains a major clinical challenge with poor prognosis. The identification of novel molecular targets is therefore crucial for developing effective treatment strategies. Eukaryotic elongation factor 2 kinase (eEF2K) is highly expressed in TNBC and known to promote tumor progression; however, the precise mechanisms underlying its oncogenic role remain elusive. In this study, we identified poly(rC)-binding protein 2 (PCBP2) as a previously unrecognized downstream substrate of eEF2K. Analysis of clinical TNBC specimens revealed a positive correlation between eEF2K and PCBP2 protein expression levels. Further studies demonstrated that site-specific phosphorylation of PCBP2 at serine 189 (Ser189) markedly promoted the malignant phenotype of TNBC cells. Mechanistically, eEF2K-mediated phosphorylation at Ser189 stabilized PCBP2 by preventing its ubiquitin-proteasome-dependent degradation. This phosphorylation-dependent stabilization, in turn, enabled PCBP2 to promote the mRNA stability of pro-oncogenic genes, including TNC, SOX5, and ITGB3, thereby driving TNBC progression. Collectively, these findings not only reveal PCBP2 as a critical downstream effector of eEF2K, but also highlight the eEF2K-PCBP2 signaling axis as a promising therapeutic target for TNBC.

Chemotherapy resistance is the primary cause of clinical treatment failure and unfavorable prognosis among breast cancer patients. Consequently, the exploration of novel molecular targets for chemotherapy resistance is warranted. Here, we demonstrated that Zinc Finger Protein 184 (ZNF184) facilitates chemoresistance in breast cancer. Through integrated bioinformatics and experimental validation, we identified that ZNF184 was highly expressed in paclitaxel‐resistant breast cancer cells. Knockdown of ZNF184 inhibited cell proliferation and re‐sensitized resistant cells to paclitaxel in vitro and in patients‐derived organoids (PDOs). Mechanistically, ZNF184 regulates the expression of stemness‐related genes CD44, OCT4, Nanog, SOX2, and ALDH1A1, thereby promoting the proliferation of breast cancer cells and subsequent paclitaxel resistance. Pan‐cancer analysis revealed the potential of ZNF184 as a prognostic and predictive biomarker for adverse clinical outcomes. Collectively, these findings reveal a previously unknown role of ZNF184 in breast cancer progression and paclitaxel resistance, providing new insights into ZNF184 as a potential therapeutic target for cancer patients.

Proteolysis‐targeting chimera (PROTAC) have emerged as a promising class of anticancer agents. Eukaryotic elongation factor 2 kinase (eEF2K), a stress‐responsive regulator of translational elongation, has emerged as a pivotal therapeutic target in triple‐negative breast cancer (TNBC) due to its critical role in sustaining cancer cell survival under nutrient stress. Building on our previous work identifying eEF2K as an oncogenic kinase, this study developed an eEF2K‐targeting PROTAC that exhibited potent antitumor activity against TNBC. Through a structure‐guided design, we identified a key allosteric pocket of eEF2K and linked its inhibitor 2S to a CRBN ligand to generate A6, a PROTAC that promotes eEF2K degradation via a conformationally optimized interface, achieving >90% target depletion while preserving the total levels of its substrate eEF2. A6 exhibited anti‐proliferative effects across TNBC cell lines by degrading eEF2K. In Vivo and in TNBC organoid models, A6 treatment significantly suppressed tumor growth, with favorable tolerability. To further enhance tumor‐specific delivery, we engineered A6@ZIF‐8, a pH‐sensitive nanocarrier that promotes drug accumulation at tumor sites compared to free A6, leading to improved therapeutic outcomes. Collectively, our data indicate that targeted degradation of eEF2K via PROTAC technology constitutes a novel and therapeutically relevant intervention strategy for TNBC.

Targeting the IGF1 system holds promise as a therapeutic approach for breast cancer. However, the intricate nature of IGF1 signaling and suboptimal drug combinations have resulted in limited clinical success. This study demonstrates that silencing p90 ribosomal S6 kinase 2 (RSK2), a downstream effector of the Ras/ERK pathway, inhibits IGF1 signaling by upregulating the expression and secretion of IGFBP5, a potent inhibitor of the IGF1-IGF1R axis that competes with IGF1 for binding. Mechanistically, GATA3 is identified as a novel transcription factor for IGFBP5, and RSK2 promotes GATA3 degradation by directly binding and phosphorylating it at serine 308, thus suppressing IGFBP5 transcription. Moreover, combined treatment with the RSK2 inhibitor LJH685 and the IGF1R inhibitor PPP significantly reduces metastasis of triple-negative breast cancer (TNBC) in both in vitro and in vivo models. These findings uncover new targets for synergistic antitumor therapy in TNBC and suggest that concurrent inhibition of IGF1R and RSK2 may offer an effective combinatorial treatment strategy.

Identifying novel therapeutic targets and drugs is crucial for treating triple‐negative breast cancer (TNBC). Bufalin, a key active ingredient of the traditional Chinese medicine HuaChansu , has been employed in tumor therapy. Here, SPR‐LC‐MS/MS is employed to characterize the targets of Bufalin and found that serine/threonine kinase 33 (STK33) possesses a strong binding affinity to Bufalin. Combining molecular docking, SPR analysis, and Biotin‐pulldown analysis, it is demonstrated that STK33 can bind Bufalin. Notably, STK33 is highly expressed in TNBC and is associated with poor prognosis in TNBC patients. STK33 knockdown inhibits TNBC cell growth both in vitro and in vivo. Mechanistically, STK33 phosphorylates and stabilizes CCAR1, which promotes tumor growth and metastasis, thereby driving tumor progression. Further analyses confirmed that Methionine 245 of STK33 is required for STK33‐Bufalin interaction, and Bufalin treatment promotes the degradation of STK33 protein by destroying the STK33‐HSP90 complex. Through in vitro, in vivo, and in patient‐derived TNBC organoids, it is observed that Bufalin inhibited the TNBC cell proliferation by targeting STK33. This study not only establishes Bufalin as a putative STK33 degrader to suppress TNBC but also identifies STK33 as a pro‐cancer factor in TNBC, presenting a potential therapeutic target for TNBC.

Target identification in natural products plays a critical role in the development of innovative drugs. Bufalin, a compound derived from traditional medicines, has shown promising anti-cancer activity; however, its precise molecular mechanism of action remains unclear. Here, we employ artificial intelligence, molecular docking, and molecular dynamics simulations to elucidate the molecular mechanism of Bufalin. Using an integrated multi-predictive strategy, we identify CYP17A1, ESR1, mTOR, AR, and PRKCD as the potential targets of Bufalin. Subsequent validation via surface plasmon resonance, biotin pulldown, and thermal shift assays confirms Bufalin’s direct binding to ESR1, which encodes estrogen receptor alpha (ERα). Molecular docking analyses pinpoint Bufalin’s selective interaction with Arg394 on ERα. Molecular dynamic simulations further show that Bufalin acts as a molecular glue, enhancing the interaction between ERα and the E3 ligase STUB1, thereby promoting proteasomal degradation of ERα. Given the therapeutic potential of ERα degradation in overcoming endocrine resistance, we investigate the inhibitory effect of Bufalin on endocrine-resistant models and prove Bufalin reverses Tamoxifen resistance in vitro, in vivo, and in patient-derived breast cancer organoids from tamoxifen-relapsed cases. Collectively, our findings indicate that Bufalin functions as a molecular glue to degrade ERα, offering a potential therapeutic strategy for reversing Tamoxifen resistance.