Applying nanosecond pulse electric fields to treat skin cancer

描述（由申请人提供）：我们发现，纳秒范围内的极短电脉冲（nsPEF）可用于治疗小鼠皮肤癌，效果显著。对小鼠黑色素瘤施加300个持续时间为300 ns、振幅为40 kV/cm的脉冲，肿瘤在两周内消退90%。如果在那个时候进行第二次这样的治疗，肿瘤就可以完全消除。总电场暴露时间为1.8微秒就会使这些肿瘤自毁。该机制不涉及热疗，因为我们在脉冲应用期间测量了肿瘤内的温度，升高不超过3℃。我们已经确定的两个目标是细胞核和肿瘤的血液供应。应用nsPEF后，肿瘤细胞核在几分钟内缩小到原来的一半大小，流向肿瘤的血液停止约两周。我们一直在对36只老鼠进行长期研究。虽然18个未治疗的对照肿瘤均未完全缓解，但所有18个nspef治疗的肿瘤均表现出至少120天的完全缓解且无复发。在接受nspef治疗的小鼠中，黑色素瘤细胞向肺部和肝脏转移的比率也比对照组低得多。在此，我们建议扩展该疗法，研究nsPEF对小鼠鳞状细胞癌的影响，并确定完全消除小鼠皮肤上这些肿瘤的最佳脉冲参数。我们还将确定当黑色素瘤生长到直径8mm时，nsPEF治疗是否能减少黑色素瘤的转移。我们还将确定nsPEFs是否有效治疗由天然表皮细胞产生的皮肤肿瘤。接下来，我们将确定nsPEF触发肿瘤消退的机制。我们将研究活性氧的作用，因为它们可以产生氧化应激诱导的DNA损伤。我们还将研究细胞凋亡途径的参与，因为它也可能导致DNA断裂。这项工作将决定这项新技术在未来皮肤肿瘤治疗中的用处。如果这种方法可以可靠地用于消除恶性皮肤病变，它将提供一种受欢迎的、无疤痕的手术替代方案，每年可以改善数十万皮肤病患者的生活质量。这项研究将探索一种新型的癌症治疗方法，即用超短电脉冲治疗皮肤肿瘤。这种治疗方法会引导肿瘤自我毁灭，并阻止血液流向肿瘤。这有望成为一种无疤痕疗法，可以取代手术，并改善每年数十万接受皮肤癌治疗的皮肤病患者的生活质量。

DESCRIPTION (provided by applicant): We have found that extremely short electric pulses in the nanosecond range (nsPEF) can be used to treat skin cancer in mice with striking results. When 300 pulses that are 300 ns in duration and 40 kV/cm in amplitude are applied to murine melanomas, the tumors regress by 90% within two weeks. If a second such treatment is applied at that time, the tumors can be completely eliminated. A total electric field exposure time of 1.8 microseconds causes these tumors to self-destruct. The mechanism does not involve hyperthermia because we have measured the temperature within the tumor during pulse application to increase no more than 3 oC. Two targets that we have identified are the cell nucleus and the tumor's blood supply. The tumor cell nuclei shrink to half of their original size within minutes after nsPEF application and the blood flow to the tumor is halted for about two weeks. We have been conducting a long-term study of 36 mice. While none of the 18 untreated control tumors exhibited complete remission, all of the 18 nsPEF-treated tumors exhibited complete remission without recurrence for at least 120 days. The rate of metastasis of melanoma cells to lung and liver was also much lower in nsPEF-treated mice that it was in controls. Here we propose to extend this therapy to investigate the effect of nsPEF on murine squamous cell carcinoma and determine the optimal pulse parameters to completely eliminate these tumors in mouse skin. We will also determine if nsPEF treatment reduces metastasis of melanomas that are treated with nsPEF when they have grown to 8 mm in diameter. We will also determine if nsPEFs are an effective treatment of a skin tumor that has arisen from native epidermal cells. Next we will identify the mechanisms by which nsPEF triggers tumor regression. We will investigate the role of reactive oxygen species because they can generate oxidative stress-induced DNA damage. We will also investigate the involvement of the apoptosis pathway since that can also lead to DNA fragmentation. This work should determine how useful this new technology will be in future treatments of skin tumors. If this approach can be reliably used to eliminate malignant skin lesions, it could offer a welcome, scar-free alternative to surgery that could improve the quality of life for hundreds of thousands of dermatology patients yearly. This research will explore a new type of cancer therapy in which skin tumors are treated with ultra-short electric pulses. This treatment instructs the tumor to self-destruct and stops blood flow to the tumor. This promises to become a scar-free therapy that could replace surgery and improve the quality of life for hundreds of thousands of dermatology patients treated for skin cancer each year.