YC-1: Soluble Guanylyl Cyclase Activator & HIF-1α Inhibitor for Cancer and Hypoxia Research

Executive Summary: YC-1 (5-(1-benzyl-1H-indazol-3-yl)furan-2-yl)methanol is a crystalline small molecule that activates soluble guanylyl cyclase (sGC) and inhibits hypoxia-inducible factor-1α (HIF-1α) transcriptional activity (APExBIO). It blocks HIF-1α expression at the post-transcriptional level, reducing the expression of hypoxia-inducible genes in tumor models (source). YC-1 demonstrates an IC₅₀ of 1.2 µM for hypoxia-induced HIF-1 transcriptional inhibition in vitro (APExBIO). The compound is soluble at ≥30.4 mg/mL in DMSO and ≥16.2 mg/mL in ethanol, but insoluble in water. Its robust activity profile and reproducible high purity (≥98%) support its widespread use in cancer, angiogenesis, and hypoxia pathway research (toloxatonecompound.com).

Biological Rationale

Hypoxia-inducible factor-1α (HIF-1α) is a transcription factor that regulates genes essential for tumor survival, proliferation, and metastasis under low oxygen (hypoxic) conditions. The HIF-1 pathway is central to the oxygen-sensing mechanism in mammalian cells. Aberrant activation of this pathway is implicated in cancer progression, angiogenesis, and resistance to therapy. Soluble guanylyl cyclase (sGC) is a key enzyme in the cGMP signaling pathway, mediating vascular tone, platelet aggregation, and cellular responses to nitric oxide (NO). YC-1 was developed as an anticancer agent targeting these two critical pathways, making it relevant for both basic and translational research in oncology, vascular biology, and hypoxia adaptation (llamab.com).

Mechanism of Action of YC-1 (5-(1-benzyl-1H-indazol-3-yl)furan-2-yl)methanol

YC-1 exerts dual molecular actions:

• Soluble Guanylyl Cyclase Activation: YC-1 directly stimulates sGC, increasing cGMP synthesis in the absence or presence of nitric oxide (APExBIO). Elevated cGMP mediates vasorelaxation and inhibits platelet aggregation.
• HIF-1α Inhibition: YC-1 inhibits HIF-1α accumulation under hypoxic conditions by interfering with its post-transcriptional stability and nuclear translocation (APExBIO). This results in suppression of HIF-1 target gene transcription, notably those involved in angiogenesis (e.g., VEGF), glucose metabolism, and survival.

These mechanisms collectively lead to reduced tumor vascularization, impaired adaptation to hypoxia, and decreased tumor growth in preclinical models.

Evidence & Benchmarks

• YC-1 inhibits hypoxia-induced HIF-1 transcriptional activity with an IC₅₀ of 1.2 µM in cell-based assays (APExBIO).
• Tumor xenograft models treated with YC-1 show significantly reduced tumor volume and vascularization compared to controls (3x-flag-peptide.com).
• YC-1 activates sGC and increases cGMP levels, leading to inhibition of platelet aggregation and vascular smooth muscle contraction in vitro (DOI:10.1016/j.saa.2021.120420).
• YC-1 is soluble at ≥30.4 mg/mL in DMSO, ≥16.2 mg/mL in ethanol, and insoluble in water (25°C, pH 7.4) (APExBIO).
• Purity of commercial YC-1 (SKU B7641, APExBIO) is typically ≥98%, enabling high reproducibility in experimental workflows (toloxatonecompound.com).

Applications, Limits & Misconceptions

YC-1 has broad applications in cancer biology, cardiovascular research, and studies of the hypoxia signaling pathway. Its dual action allows for precise modulation of both oxygen-sensing and cGMP signaling in cell and animal models. Researchers use YC-1 to:

• Investigate HIF-1α-dependent gene expression in hypoxia and normoxia.
• Study tumor angiogenesis inhibition and apoptosis induction.
• Model vascular tone and platelet function via cGMP signaling.

Earlier reviews, such as Optimizing Hypoxia Assays with YC-1, detail cell viability workflows, while this article provides updated solubility, purity, and IC₅₀ data for best-practice protocol design. For advanced applications, see Optimizing Cancer and Hypoxia Research with YC-1, which discusses troubleshooting and high-impact study design—this article extends those workflows with more rigorous benchmark data.

Common Pitfalls or Misconceptions

• YC-1 is not a direct nitric oxide donor. Its sGC activation is NO-independent but can be synergistic with NO.
• It does not inhibit all forms of HIF. Its primary activity is against HIF-1α, not HIF-2α or HIF-3α.
• Water insolubility limits direct aqueous application. Use appropriate solvents (DMSO or ethanol) and avoid water-based stocks.
• Not for diagnostic or clinical use. YC-1 is for laboratory research only, as per APExBIO and regulatory guidance.
• Long-term solution storage is discouraged. Prepare fresh aliquots; prolonged storage leads to loss of activity.

Workflow Integration & Parameters

YC-1 (SKU B7641) from APExBIO is supplied as a crystalline solid with a molecular weight of 304.34 Da. For in vitro use, dissolve in DMSO (≥30.4 mg/mL) or ethanol (≥16.2 mg/mL). Stock solutions should be prepared immediately before use and protected from light. For cell-based assays, dilute stock solutions into culture medium (final DMSO concentration ≤0.1% v/v is recommended). Typical experimental concentrations range from 0.5 to 10 µM, depending on cell type and endpoint. In vivo, YC-1 is commonly administered via intraperitoneal injection or oral gavage, with dosing regimens tailored to the model and research objective. For reliable hypoxia signaling readouts, include positive (e.g., DMOG) and negative controls. For further scenario-driven guidance, see Reliable Hypoxia and Cancer Pathway Research with YC-1, which this article updates with the most recent purity and storage recommendations.

Conclusion & Outlook

YC-1 (5-(1-benzyl-1H-indazol-3-yl)furan-2-yl)methanol is a dual-action research tool for dissecting the hypoxia and cGMP signaling pathways. Its reproducible purity, robust inhibitory activity against HIF-1α, and ease of integration into in vitro and in vivo workflows position it as a standard in oncology and vascular biology research. APExBIO's B7641 SKU meets stringent quality benchmarks, supporting reproducible, high-impact studies. Ongoing development of derivatives and analogs may further expand the utility of YC-1 for precision hypoxia and cancer research.