Breast cancer remains one of the leading causes of cancer-related morbidity and mortality among women worldwide. Understanding the underlying mechanisms that contribute to the aggressive nature of ER-positive variants is crucial for developing effective treatment modalities. Among the various molecular players implicated in the development and persistence of cancer stem cells, CircKIAA1617 has emerged as a significant factor worth investigating. This circular RNA has been shown to orchestrate various cellular processes, but its role in breast cancer specifically warranted this thorough examination.

One of the primary methods researchers utilized in their investigation was RNA sequencing, an advanced technique that allows for the comprehensive analysis of gene expression profiles. By comparing the RNA expression patterns in ER-positive breast cancer cells with varying levels of CircKIAA1617, the researchers discovered a striking correlation between high levels of this circular RNA and enhanced cancer stem cell characteristics. This finding suggests a potential oncogenic role of CircKIAA1617 in promoting cellular attributes associated with self-renewal and tumorigenesis.

Diving deeper into the molecular mechanisms, the authors discovered that CircKIAA1617 mediates its effects through the regulation of USP14 and PGRMC1. USP14, a deubiquitinating enzyme, plays a pivotal role in protein stability and degradation pathways. In the context of cancer, its interactions with various substrates can influence critical cellular processes, including apoptosis and cell cycle progression. The researchers demonstrated that CircKIAA1617 enhances the stability of USP14, leading to an increase in its activity, which, in turn, promotes a cellular environment conducive to stemness.

Another key player identified in this study is PGRMC1, a multifunctional protein known for its involvement in various cellular signaling pathways. The interplay between USP14 and PGRMC1 appears to be central to the reprogramming of autophagy and lipid metabolism in the context of ER-positive breast cancer. Autophagy, a cellular degradation process, is often co-opted by cancer cells to survive in unfavorable conditions, while altered lipid metabolism fuels the energetic demands of rapidly proliferating tumor cells. By modulating these pathways, CircKIAA1617 positions itself as a critical regulator of cancer cell plasticity.

The researchers further demonstrated that silencing CircKIAA1617 led to decreased expression levels of USP14 and PGRMC1, effectively impairing the cancer stemness characteristics observed in ER-positive breast cancer cell lines. This finding highlights the potential of targeting CircKIAA1617 as a therapeutic approach to curb the aggressive behavior of these tumors. The ability to manipulate cancer stem cell properties through RNA-based interventions represents a groundbreaking approach in cancer therapeutics.

Interestingly, the study also unveiled the involvement of lipid metabolism in promoting cancer stemness through the CircKIAA1617-USP14-PGRMC1 axis. The researchers observed that high levels of CircKIAA1617 were associated with increased fatty acid synthesis and oxidation, both of which are pivotal for cancer cell survival and proliferation. This metabolic reprogramming could represent an adaptive mechanism by which cancer cells sustain themselves in a hostile tumor microenvironment, thus further emphasizing the multifaceted role of CircKIAA1617 in tumor biology.

Furthermore, the implications of this study extend beyond breast cancer alone. The pathways elucidated in this research may provide insights into similar mechanisms operating in other cancers characterized by stemness, thus broadening the potential impact of targeting CircKIAA1617 or its downstream effectors. The discoveries made by Yang and colleagues could pave the way for novel therapeutic strategies that exploit the vulnerabilities of cancer stem cells, which are notoriously resistant to conventional treatments.

In summary, the research led by Yang, Li, and Wang elucidates a novel regulatory mechanism involving CircKIAA1617 in ER-positive breast cancer. By promoting stemness through USP14 and PGRMC1-mediated autophagy and lipid metabolism reprogramming, this circular RNA has opened new avenues for targeted therapies aimed at eradicating cancer stem cells. The findings not only deepen our understanding of the molecular intricacies underpinning breast cancer but also highlight the potential for innovative treatment strategies that could dramatically improve patient outcomes in this challenging disease landscape.

Overall, this study exemplifies the importance of investigating the non-coding regions of RNA and their contributions to cancer biology. As research continues to unravel the complexity of cancer, circular RNAs like CircKIAA1617 could become pivotal players in a new era of precision oncology. As such, future studies will undoubtedly build on these findings, exploring the clinical applicability of targeting CircKIAA1617 and its associated pathways in the fight against ER-positive breast cancer and beyond. The anticipation surrounding these emerging therapeutic strategies reflects the growing recognition of the transformative potential that lies within the realms of RNA biology.

Surprisingly, while much attention has been directed towards the more conventional oncogenes and tumor suppressors, investigations like these illuminate the significance of previously overlooked molecular entities. Not only do they challenge existing paradigms regarding gene regulation and expression, but they also inspire new quests for biomarkers and therapeutic targets that can revolutionize cancer treatment. The implications of this work are significant, not only for the scientific community but also for patients grappling with the challenges posed by ER-positive breast cancer.

In conclusion, Yang, Li, and Wang’s research into CircKIAA1617 offers a compelling narrative that underscores the dynamic interplay between RNA biology and cancer. By detailing how this circular RNA modulates critical processes associated with stemness and metabolism, this study lays the groundwork for future endeavors aimed at translating these findings into tangible clinical benefits. Protein levels, enzymatic activities, and metabolic pathways are all malleable to intervention; thus, harnessing the power of CircKIAA1617 may ultimately lead to innovative therapeutic approaches that will enhance the lives of those affected by this formidable disease.

Subject of Research: Role of CircKIAA1617 in promoting stemness in ER-positive breast cancer.

Article Title: CircKIAA1617 promotes stemness via USP14/PGRMC1-mediated autophagy and lipid metabolism reprogramming in ER-positive breast cancer.

Article References:

Yang, J., Li, Y., Wang, Z. et al. CircKIAA1617 promotes stemness via USP14/PGRMC1-mediated autophagy and lipid metabolism reprogramming in ER-positive breast cancer. Mol Cancer (2026). https://doi.org/10.1186/s12943-026-02580-2

Image Credits: AI Generated

DOI:

Keywords: CircKIAA1617, ER-positive breast cancer, cancer stem cells, USP14, PGRMC1, autophagy, lipid metabolism, RNA biology, targeted therapy.

ER-positive breast cancer represents a significant subset of breast cancer diagnoses globally, distinguished by its reliance on estrogen receptor signaling to drive tumor growth and survival. Despite advances in endocrine therapies, resistance mechanisms inevitably emerge, leading to therapeutic failure and disease progression. This new research identifies a previously underappreciated link between ESR1 activity and autophagy—a catabolic process essential for maintaining cellular homeostasis and stress tolerance—demonstrating that ESR1 exerts a suppressive control over p62/SQSTM1-dependent autophagy pathways in these tumor cells.

The autophagy receptor protein p62/SQSTM1 serves as a nodal regulator for selective autophagy, facilitating the degradation of ubiquitinated proteins and damaged organelles. Importantly, p62 is known to influence oxidative stress responses by mediating the turnover of pro-oxidant proteins and promoting cellular adaptation to stress. The study illuminates how suppression of ESR1 augments p62 expression and functionality, leading to a resurgence of autophagic flux. This process heightens cellular cleanses of oxidative damage and misfolded proteins, thereby sensitizing cancer cells to exogenous challenges such as reactive oxygen species and ionizing radiation.

Methodologically, the team employed an integrative approach combining molecular genetic techniques, cellular assays, and in vivo models to dissect the ESR1-p62 autophagy axis. By knockdown or pharmacological inhibition of ESR1, researchers observed restored autophagic activity in ER-positive breast cancer cell lines, accompanied by increased vulnerability to oxidative stress and radiotherapy-induced cytotoxicity. Conversely, enforced ESR1 expression attenuated autophagy, underscoring the receptor’s suppressive role in these pathways.

From a therapeutic perspective, this discovery unveils ESR1 as a dual-function target—beyond its canonical transcriptional regulation of proliferative genes, its modulation appears pivotal in orchestrating autophagy-mediated stress responses. This insight challenges established dogma, suggesting that endocrine therapies could be optimized or combined with autophagy-modulating agents to overcome resistant phenotypes and enhance treatment efficacy. Such combination strategies could achieve higher rates of tumor cell eradication by synergistically impairing adaptive survival mechanisms.

The intricate interplay between ESR1 signaling and autophagy impacts how ER-positive breast cancer cells navigate oxidative onslaughts, a situation commonly encountered during radiation therapy. Radiation generates high levels of reactive oxygen species (ROS), which induce DNA damage and cellular apoptosis; however, cancer cells frequently deploy autophagy to mitigate these insults, fostering radiotherapy resistance. By reinstating p62-dependent autophagy, ESR1 inhibition disrupts this protective shield, rendering cancer cells more susceptible to ROS-mediated apoptosis and improving overall treatment outcomes.

Additionally, the results elucidate the molecular cascades downstream of ESR1 that converge on autophagic machinery, including the modulation of key autophagy-related genes and signal transduction pathways. The study highlights the complex regulatory network where estrogen receptor influences autophagy markers such as LC3 and ATG proteins through transcriptional and post-translational mechanisms, aligning cellular catabolic processes with hormone receptor status and environmental stressors.

Importantly, the translational potential of this work extends to the clinical realm. The findings advocate for the development of next-generation ESR1 inhibitors with enhanced specificity for autophagy pathway restoration. Moreover, biomarkers related to p62/SQSTM1 expression and autophagic flux could serve as predictive tools for identifying patients likely to benefit from combined endocrine and autophagy-targeted therapies, paving the way for precision oncology approaches.

This paradigm-shifting research also prompts reevaluation of current therapeutic algorithms by integrating autophagy modulation as a cornerstone in managing ER-positive breast cancer. It calls attention to the balance between endocrine resistance mechanisms and cellular quality control systems, suggesting a synergistic vulnerability that could be tactically exploited. The prospect of overcoming radioresistance through autophagy reactivation offers a promising strategy to enhance the curative potential of combined modality therapies.

While this study primarily focuses on ER-positive breast cancer, the mechanistic insights into ESR1’s role in autophagy may have broader implications across hormone-driven malignancies. Future research is encouraged to explore whether similar autophagy regulatory networks exist in other estrogen-responsive cancers such as endometrial or ovarian tumors, potentially extending the impact of these findings beyond breast cancer.

In-depth molecular analysis revealed that ESR1 signaling dampens p62/SQSTM1 transcription and impairs its functional interactions with ubiquitinated cargo, which are critical for selective autophagy initiation. Reversing this repression through ESR1 targeting releases autophagic inhibition, facilitating enhanced clearance of cellular debris and promoting apoptotic cascades under stress conditions. Such mechanistic clarity strengthens the foundation for rational drug design aimed at modulating this axis.

Moreover, the study underscores the dynamic nature of cancer cell adaptation, whereby hormonal signaling pathways intersect with intracellular degradation systems to fine-tune survival responses. This crosstalk provides a fertile ground for discovering vulnerabilities unique to cancer cells, distinct from normal tissue counterparts, thereby minimizing off-target effects and improving therapeutic index.

The authors advocate a multidisciplinary approach to further refine ESR1-autophagy interactions, including protein structural studies and in vivo imaging of autophagic flux in clinical samples. These efforts will be crucial to translate preclinical observations into robust clinical interventions that can improve patient survival and quality of life in ER-positive breast cancer.

Ultimately, by charting a previously uncharted territory between estrogen receptor function and autophagy regulation, this seminal study sets a new standard for innovative cancer research. It challenges the research community to rethink existing biological paradigms and leverage molecular synergies for designing next-generation cancer therapeutics tailored to the complex biology of hormone-responsive tumors.

In conclusion, the restoration of SQSTM1-dependent autophagy through precise targeting of ESR1 constitutes a highly promising therapeutic strategy to sensitize ER-positive breast cancer cells to oxidative and radiation stress. This insight not only deepens our understanding of breast cancer biology but also offers an exciting clinical translational opportunity that could significantly improve outcomes for patients battling this prevalent and often formidable disease.

Subject of Research: Restoration of SQSTM1-dependent autophagy via ESR1 targeting in ER-positive breast cancer and its impact on sensitization to oxidative and radiation stress.

Article Title: Targeting ESR1 restores SQSTM1-dependent autophagy and sensitizes ER-positive breast cancer to oxidative and radiation stress.

Article References:
Yang, YF., He, ZJ., Kuo, HH. et al. Targeting ESR1 restores SQSTM1-dependent autophagy and sensitizes ER-positive breast cancer to oxidative and radiation stress. Cell Death Discov. 11, 451 (2025). https://doi.org/10.1038/s41420-025-02755-8

Image Credits: AI Generated

DOI: https://doi.org/10.1038/s41420-025-02755-8