Dual-Laser Approach Transforms Breast Cancer Photothermal Therapy

Breast cancer remains the most frequently diagnosed malignancy among women worldwide, posing persistent challenges despite significant advances in early detection and treatment. The quest for innovative therapies that minimize invasiveness while maximizing efficacy remains relentless. Recently, attention has increasingly shifted toward phototheranostics, a cutting-edge field that harnesses the power of light for the dual purpose of cancer detection and treatment. This approach offers unique advantages, such as non-invasive, real-time imaging paired with precise, localized therapy, enabling clinicians to simultaneously diagnose and combat tumors with greater accuracy.

Among phototheranostic techniques, photothermal therapy (PTT) stands out as a promising modality. PTT utilizes photothermal agents capable of absorbing specific wavelengths of light and converting them efficiently into heat, thereby raising temperatures locally to induce tumor cell death. A critical aspect of this approach lies in the tumor-targeting ability of photothermal agents, which allows selective ablation of malignant tissue while sparing normal cells. However, widespread clinical adoption of PTT has been hampered by several obstacles, chief among them the risk of overheating, which can cause collateral damage to surrounding healthy tissues, and the sometimes insufficient tumor eradication leading to relapse.

Addressing these challenges, a recent collaborative research effort led by Professor ZHANG Pengfei of the Shenzhen Institute of Advanced Technology (SIAT) and his international colleagues has introduced an innovative dual-laser photothermal therapy (DLPTT) strategy. Their work, published in the prestigious journal Proceedings of the National Academy of Sciences, pioneers the use of two wavelengths—808 nm and 1,064 nm—in a sequential treatment protocol designed to enhance tumor ablation while reducing adverse effects. This breakthrough leverages specially engineered near-infrared photothermal agents exhibiting aggregation-induced emission (AIE) properties, which bolster imaging clarity and photothermal conversion efficiency.

The DLPTT strategy unfolds in two carefully calibrated stages. Initially, the tumor site undergoes a brief, high-temperature exposure using an 808 nm laser for approximately two minutes, achieving local temperatures around 50 °C. This phase achieves a crucial biological effect: it induces DNA damage in tumor cells and suppresses the expression of heat shock protein 70 (HSP70), a molecular chaperone known to confer thermotolerance. By inhibiting HSP70, this step effectively dismantles a key cellular defense mechanism, rendering cancer cells more vulnerable to subsequent treatment.

Following this priming stage, the therapy transitions to a longer-duration 1,064 nm laser irradiation, maintained at a slightly lower temperature near 43 °C over 13 minutes. This gentler heating phase is optimized to ablate residual tumor cells without provoking excessive inflammation or thermal injury to adjacent healthy tissues. The sequential use of two laser wavelengths capitalizes on their distinct tissue penetration depths and absorption profiles, enabling precise modulation of the tumor microenvironment and maximizing treatment efficacy.

A hallmark of this DLPTT protocol is the integration of second near-infrared window (NIR-II) fluorescence imaging, combined with photoacoustic imaging techniques. NIR-II imaging offers profound advantages, including deeper tissue penetration and significantly reduced scattering, which together produce images with enhanced signal-to-noise ratios. This highly sensitive imaging modality facilitates real-time visualization of tumors, even in deep tissue contexts, allowing clinicians to accurately localize and monitor the response of malignant lesions throughout therapy. Photoacoustic imaging complements this by providing additional anatomical and functional information, enriching the precision of treatment guidance.

Preclinical validation of this approach was conducted using the 4T1 breast cancer mouse model, a well-established system that closely mimics aggressive human breast cancer behavior. The results demonstrated that DLPTT significantly suppressed tumor growth, outstripping conventional single-laser PTT approaches in both effectiveness and safety. Importantly, treated animals showed no marked side effects, with stable body weights and no evident toxicity, underscoring the biosafety profile of this dual-laser regimen.

Further in vivo studies confirmed that DLPTT minimized systemic inflammatory responses, a common complication in thermal therapies. The reduction in inflammatory cytokine production suggests that the dual-laser strategy not only eradicates cancer cells but also preserves normal tissue homeostasis, which is vital for preventing adverse immune reactions and facilitating patient recovery.

Beyond its immediate therapeutic impact, this research also marks a significant advancement in the development of aggregation-induced emission (AIE) materials. AIE luminogens are a novel class of compounds whose fluorescence intensities increase upon aggregation, contrasting with conventional fluorophores that often suffer from quenching. Their use in photothermal agents enhances both imaging clarity and therapeutic precision, positioning them as versatile tools in the expanding field of phototheranostics.

Looking forward, the authors envision a promising future where DLPTT is integrated synergistically with immunotherapy. The combination of precise tumor ablation and immune system modulation could provide a powerful strategy to combat cancer metastasis and recurrence, addressing two of the most daunting challenges in oncology. By dismantling tumor cells locally and simultaneously activating systemic antitumor immunity, such combinatorial therapies hold the potential to redefine cancer care.

This groundbreaking study exemplifies the transformative potential of light-based technologies in modern medicine. By refining photothermal therapy through innovative laser strategies and advanced imaging, it paves the way for minimally invasive, highly effective cancer treatments that prioritize patient safety without compromising therapeutic potency. As research continues to evolve, phototheranostics promises to become a cornerstone of personalized oncology, offering hope for millions affected by breast cancer worldwide.

News Publication Date: 9-Jun-2025

Web References:
https://doi.org/10.1073/pnas.2503574122