Search

Despite advances in breast cancer treatments and related 5-year survival outcomes, metastatic breast cancer cures remain elusive. The current standard of care includes a combination of surgery, radiation therapy and drug therapy. However, even the most advanced procedures and treatments do not prevent breast cancer recurrence and metastasis. Once metastasis occurs, patient prognosis is poor. Recent elucidation of the spatiotemporal transit of metastatic cancer cells from primary tumor sites to distant sites provide an opportunity to integrate knowledge of drug disposition in our effort to enhance drug localization and exposure in cancer laden tissues . Novel technologies have been developed, but could be further refined to facilitate the distribution of drugs to target cancer cells and tissues. The purpose of this review is to highlight the challenges in metastatic breast cancer treatment and focus on novel drug combination and nanotechnology approaches to overcome the challenges. With improved definition of metastatic tissue target, directed localization and retention of multiple, pharmacologically active drugs to tissues and cells of interest may overcome the limitations in breast cancer treatment that may lead to a cure for breast cancer., Competing Interests: Declaration of Competing Interest The authors declare no conflict of interest., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Purpose: To develop drug-combination nanoparticles (DcNPs) composed of hydrophilic gemcitabine (G) and hydrophobic paclitaxel (T) and deliver both drugs to metastatic cancer cells., Methods: GT DcNPs were evaluated based on particle size and drug association efficiency (AE%). The effect of DcNP on GT plasma time-course and tissue distribution was characterized in mice and a pharmacokinetic model was developed. A GT distribution study into cancer nodules (derived from 4 T1 cells) was performed., Results: An optimized GT DcNP composition (d = 59.2 nm ±9.2 nm) was found to be suitable for IV formulation. Plasma exposure of G and T were enhanced 61-fold and 3.8-fold when given in DcNP form compared to the conventional formulation, respectively. Mechanism based pharmacokinetic modeling and simulation show that both G and T remain highly associated to DcNPs in vivo (G: 98%, T:75%). GT DcNPs have minimal distribution to healthy organs with selective distribution and retention in tumor burdened tissue. Tumor bearing lungs had a 5-fold higher tissue-to-plasma ratio of gemcitabine in GT DcNPs compared to healthy lungs., Conclusions: DcNPs can deliver hydrophilic G and hydrophobic T together to cancer nodules and produce long acting exposure, likely due to stable GT association to DcNPs in vivo.

Early diagnosis along with new drugs targeted to cancer receptors and immunocheckpoints have improved breast cancer survival. However, full remission remains elusive for metastatic breast cancer due to dose-limiting toxicities of heavily used, highly potent drug combinations such as gemcitabine and paclitaxel. Therefore, novel strategies that lower the effective dose and improve safety margins could enhance the effect of these drug combinations. To this end, we developed and evaluated a novel drug combination of gemcitabine and paclitaxel (GT). Leveraging a simple and scalable drug-combination nanoparticle platform (DcNP), we successfully prepared an injectable GT combination in DcNP (GT DcNP). Compared to a Cremophor EL/ethanol assisted drug suspension in buffer (CrEL), GT DcNP exhibits about 56-fold and 8.6-fold increases in plasma drug exposure (area under the curve, AUC) and apparent half-life of gemcitabine respectively, and a 2.9-fold increase of AUC for paclitaxel. Using 4T1 as a syngeneic model for breast cancer metastasis, we found that a single GT (20/2 mg/kg) dose in DcNP nearly eliminated colonization in the lungs. This effect was not achievable by a CrEL drug combination at a 5-fold higher dose (i.e., 100/10 mg/kg GT). A dose-response study indicates that GT DcNP provided a therapeutic index of ~15.8. Collectively, these data suggest that GT DcNP could be effective against advancing metastatic breast cancer with a margin of safety. As the DcNP formulation is intentionally designed to be simple, scalable, and long-acting, it may be suitable for clinical development to find effective treatment against metastatic breast cancer., Competing Interests: The authors have read the journal's policy and the authors of this manuscript have the following competing interests: The authors would like to declare the following provisional patent application associated with this research: Composition and Method to Prepare Long-Acting Injectable Suspension Containing Multiple Cancer Drugs (application no. 62/982557). This does not alter our adherence to PLOS ONE policies on sharing data and materials.

Despite the availability of molecularly targeted treatments such as antibodies and small molecules for human epidermal growth factor receptor 2 (HER2), hormone receptor (HR), and programmed death-ligand 1 (PD-L1), limited treatment options are available for advanced metastatic breast cancer (MBC), which constitutes ~90% mortality. Many of these monotherapies often lead to drug resistance. Novel MBC-targeted drug-combination therapeutic approaches that may reduce resistance are urgently needed. We investigated intercellular adhesion molecule-1 (ICAM-1), which is abundant in MBC, as a potential target to co-localize two current drug combinations, gemcitabine (G) and paclitaxel (T), assembled in a novel drug-combination nanoparticle (GT DcNP) form. With an ICAM-1-binding peptide (referred to as LFA1-P) coated on GT DcNPs, we evaluated the role of the LFA1-P density in breast cancer cell localization in vitro and in vivo. We found that 1–2% LFA1-P peptide incorporated on GT DcNPs provided optimal cancer cell binding in vitro with ~4× enhancement compared to non-peptide GT DcNPs. The in vivo probing of GT DcNPs labeled with a near-infrared marker, indocyanine green, in mice by bio-imaging and G and T analyses indicated LFA1-P enhanced drug and GT DcNP localization in breast cancer cells. The target/healthy tissue (lung/gastrointestinal (GI)) ratio of particles increased by ~60× compared to the non-ligand control. Collectively, these data indicated that LFA1 on GT DcNPs may provide ICAM-1-targeted G and T drug combination delivery to advancing MBC cells found in lung tissues. As ICAM-1 is generally expressed even in breast cancers that are triple-negative phenotypes, which are unresponsive to inhibitors of nuclear receptors or HER2/estrogen receptor (ER) agents, ICAM-1-targeted LFA1-P-coated GT DcNPs should be considered for clinical development to improve therapeutic outcomes of MBCs. [ABSTRACT FROM AUTHOR]