A Machine Learning-optimized system for on demand, pulsatile, photo- and chemo-therapeutic treatment using near-infrared responsive MoS 2 -based microparticles in a breast cancer model.

Cancer therapy research is of high interest because of the persistence and mortality of the disease and the side effects of traditional therapeutic methods, while often multimodal treatments are necessary based on the patient's needs. The development of less invasive modalities for recurring treatment cycles is thus of critical significance. Herein, a light-activatable microparticle system was developed for localized, pulsatile delivery of anticancer drugs with simultaneous thermal ablation, by applying controlled ON-OFF thermal cycles using near-infrared laser irradiation. The system is composed of poly(caprolactone) microparticles of 200 µm size with incorporated molybdenum disulfide (MoS 2 ) nanosheets as the photothermal agent and hydrophilic doxorubicin or hydrophobic violacein, as model drugs. Upon irradiation the nanosheets heat up to ≥50 °C leading to polymer matrix melting and release of the drug. MoS 2 nanosheets exhibit high photothermal conversion efficiency and allow for application of low power laser irradiation for the system activation. A Machine Learning algorithm was applied to acquire optimal laser operation conditions; 0.4 W/cm 2 laser power at 808 nm, 3-cycle irradiation, for 3 cumulative minutes. In a mouse subcutaneous model of 4T1 triple-negative breast cancer, 25 microparticles were intratumorally administered and after 3-cycle laser treatment the system conferred synergistic phototherapeutic and chemotherapeutic effect. Our on-demand, pulsatile synergistic treatment resulted in increased median survival up to 40 days post start of treatment compared to untreated mice, with complete eradication of the tumors at the primary site. Such a system could have potential for patients in need of recurring cycles of treatment on subcutaneous tumors.

Intrathecal Viral Vector Delivery of Trastuzumab Prevents or Inhibits Tumor Growth of Human HER2-Positive Xenografts in Mice.

Breast cancer brain metastases are a deadly sequela of primary breast tumors that overexpress human epidermal growth factor receptor 2 (HER2); median survival for patients with these tumors is 10 to 13 months from the time of diagnosis. Current treatments for HER2-positive breast cancer brain metastases are invasive, toxic, and largely ineffective. Here, we have developed an adeno-associated virus serotype 9 (AAV9) vector to express the anti-HER2 monoclonal antibody trastuzumab (Herceptin) in vivo A single prophylactic intrathecal administration of AAV9.trastuzumab vector in a novel orthotopic Rag1-/- murine xenograft model of HER2-positive breast cancer brain metastases significantly increased median survival, attenuated brain tumor growth, and preserved both the HER2 antigen specificity and the natural killer cell-associated mechanism of action of trastuzumab. When administered as a tumor treatment, AAV9.trastuzumab increased median survival. Dose-escalation studies revealed that higher doses of AAV9.trastuzumab resulted in smaller tumor volumes. Our results indicate that intrathecal AAV9.trastuzumab may provide significant antitumor activity in patients with HER2-positive breast cancer brain metastases.Significance: Intrathecal delivery of trastuzumab via adeno-associated virus has the potential to become a novel, integral part of adjuvant therapy for patients with HER2-positive breast cancer brain metastases. Cancer Res; 78(21); 6171-82. ©2018 AACR.

Primary CTL response magnitude in mice is determined by the extent of naive T cell recruitment and subsequent clonal expansion.

CD8+ T cell responses to viral infection are characterized by the emergence of dominant and subdominant CTL populations. The immunodominance hierarchies of these populations are highly reproducible for any given spectrum of virus-induced peptide-MHCI complexes and are likely determined by multiple factors. Recent studies demonstrate a direct correlation between naive epitope-specific CD8+ T cell precursor (CTLp) frequency and the magnitude of the response after antigen challenge. Thus, the number of available precursors in the naive pool has emerged as a key predictor of immunodominance. In contrast to this, we report here no consistent relationship between CTLp frequency and the subsequent magnitude of the immune response for 4 influenza virus-derived epitopes following intranasal infection of mice with influenza A virus. Rather, the characteristic, antigen-driven T cell immunodominance hierarchy was determined by the extent of recruitment from the available pool of epitope-specific precursors and the duration of their continued expansion over the course of the infection. These findings suggest possibilities for enhancing protective immune memory by maximizing both the size and diversity of typically subdominant T cell responses through rational vaccine design.