Multiparameter Analysis of Off-Target Effects of Dasatinib on Bone Homeostasis in Patients With Newly Diagnosed Chronic Myelogenous Leukemia

A phase I trial of palbociclib and bosutinib with fulvestrant in patients with metastatic hormone receptor positive and HER2 negative (HR+ HER2-) breast cancer refractory to an aromatase inhibitor and a CDK4/6 inhibitor

Standard treatment for metastatic hormone positive (HR+) breast cancer includes a combination of a CDK4/6 inhibitor and antiestrogen therapy. Despite durable responses, eventual endocrine resistance results in disease progression. The Src/Abl pathway has been shown to mediate endocrine resistance in breast cancer, thus providing a promising target for novel therapies. Bosutinib is a tyrosine kinase inhibitor that targets the Src/Abl pathway, which has been studied in hematologic malignancies. Preclinical data suggests that the addition of bosutinib to a CDK4/6 inhibitor and antiestrogen therapy has the potential to reverse endocrine resistance. This is a phase I, single arm, open-label clinical trial in which we evaluate the combination of palbociclib and fulvestrant with bosutinib in metastatic HR+ breast cancer. Patients with confirmed advanced HR+/HER2- breast cancer who have received no more than three lines of chemotherapy and have progressed on at least one aromatase inhibitor and one CDK4/6 inhibitor will be enrolled. Participants will be given a combination of palbociclib, fulvestrant and bosutinib over 28-day cycles. The primary objective of this study is to assess the safety and tolerability of bosutinib in combination with palbociclib and fulvestrant in the study population. Secondary objectives are to 1) determine the anti-tumor effect of this therapeutic combination by assessing overall response rate (ORR) and clinical benefit rate (CBR) after 6 months of treatment, 2) to determine the clinical pharmacology parameters of bosutinib in this regimen, and 3) to build a tissue repository at Georgetown Lombardi Comprehensive Cancer Center for further translational study.

Peruvoside is a novel Src inhibitor that suppresses NSCLC cell growth and motility by downregulating multiple Src-EGFR-related pathways

The tyrosine kinase Src plays an essential role in the progression of many cancers and is involved in several epidermal growth factor receptor (EGFR)-mediated signalling pathways. To improve the efficacy of lung cancer treatments, this study aimed to identify novel compounds that can disrupt the Src-EGFR interaction and that are less dependent on EGFR status with wild-type and mutations than other compounds. We used the Src pY419 ELISA as the platform to screen a compound library of more than 400 plant-derived active ingredients and identified peruvoside as a candidate Src-EGFR crosstalk inhibitor. The effects of peruvoside were evaluated by western blotting, cell function assays, combination Index (CI)-isobologram analyses and in vivo experiments. Peruvoside significantly suppressed the phosphorylation of Src, EGFR, and signal transducer and activator of transcription 3 (STAT3) in a dose- and time-dependent manner and somewhat suppressed their protein expression. Cell function assays revealed that peruvoside inhibited the proliferation, invasion, migration, and colony formation of lung cancer cells in vitro and tumour growth in vivo. Furthermore, peruvoside sensitized gefitinib-resistant tumour cells (A549, PC9/gef and H1975) to gefitinib treatment, indicating that peruvoside may exert synergistic effects when used in combination with established therapeutic agents. Our data also demonstrated that the inhibitory effects of peruvoside on lung cancer progression might be attributed to its ability to regulate Src, phosphoinositide 3-kinase (PI3K), c-Jun N-terminal kinase (JNK), Paxillin, p130cas, and EGFR. Our findings suggest that peruvoside suppresses non-small-cell lung carcinoma (NSCLC) malignancy by downregulating multiple Src-related pathways and could serve as a potential base molecule for developing new anticancer drugs and therapeutic strategies for lung cancer.

Can Precision Electrophile Signaling Make a Meaningful and Lasting Impression in Drug Design?

For several years, drugs with reactive electrophilic appendages have been developed. These units typically confer prolonged residence time of the drugs on their protein targets, and may assist targeting shallow binding sites and/or improving the drug-protein target spectrum. Studies on natural electrophilic molecules have indicated that, in many instances, natural electrophiles use similar mechanisms to alter signaling pathways. However, natural reactive species are also endowed with other important mechanisms to hone signaling properties that are uncommon in drug design. These include ability to be active at low occupancy and elevated inhibitor kinetics. Herein, we discuss how we have begun to harness these properties in inhibitor design.

Glycosylated Nanoparticles Derived from RAFT Polymerization for Effective Drug Delivery to Macrophages

The functional group tolerance and simplicity of reversible addition fragmentation chain transfer (RAFT) polymerization enable its use in the preparation of a wide range of functional polymer architectures for a variety of applications, including drug delivery. Given the role of tumor-associated macrophages (TAMs) in cancer and their dependence on the tyrosine kinase receptor FMS (CSF-1R), the key aim of this work was to achieve effective delivery of an FMS inhibitor to cells using a polymer delivery system. Such a system has the potential to exploit biological features specific to macrophages and therefore provide enhanced selectivity. Building on our prior work, we have prepared RAFT polymers based on a poly(butyl methacrylate-co-methacrylic acid) diblock, which were extended with a hydrophilic block, a cross-linker, and a mannose-based monomer scaffold, exploiting the abundance of macrophage mannose receptors (MMRs, CD206) on the surface of macrophages. We demonstrate that the prepared polymers can be assembled into nanoparticles and are successfully internalized into macrophages, in part, via the MMR (CD206). Finally, we showcase the developed nanoparticles in the delivery of an FMS inhibitor to cells, resulting in inhibition of the FMS receptor. As such, this study lays the groundwork for further drug-delivery studies aimed at specifically targeting TAMs with molecularly targeted therapeutics.