Delivery of Small Molecules by Syndiotactic Peptides for Breast Cancer Therapy

Novel strategies in breast cancer management: From treatment to long-term remission

Breast cancer (BC) is the most common malignancy among women and a leading cause of cancer-related mortality worldwide. Although improvements in early detection and therapy have been made, metastatic breast cancer (mBC) continues to be an incurable disease. Although existing treatments can prolong survival and enhance quality of life, they do not provide a definitive cure. Targeted therapies have significantly improved outcomes, particularly for subtypes such as human epidermal growth factor receptor 2 (HER2)-positive and hormone receptor (HR)-positive (HR+) BC. Key innovations include antibodydrug conjugates (ADCs) and next-generation endocrine therapies. ADCs combine monoclonal antibodies with cytotoxic agents, allowing targeted delivery to tumor cells while minimizing systemic toxicity. Immunotherapy is emerging as a promising approach for aggressive subtypes, such as triple-negative breast cancer (TNBC). Strategies under investigation include chimeric antigen receptor T-cell (CAR-T) therapy, tumor-infiltrating lymphocyte (TIL) therapies, and natural killer (NK) cell treatments, all aimed at enhancing the ability of the immune system to target and eliminate resistant tumor cells. Tissue engineering, particularly hydrogel-based delivery systems, offers the potential for localized treatment. These systems enable the controlled release of therapeutic agents or immune cells directly to the tumor site, supporting tissue regeneration and enhancing immune surveillance to reduce recurrence. Despite these advancements, challenges remain, including treatment resistance, the immunosuppressive tumor microenvironment, and high costs. Overcoming these barriers requires further innovation in drug delivery systems and a deeper understanding of tumor biology.

Structural regression modelling of peptide based drug delivery vectors for targeted anti-cancer therapy

Drug resistance in cancer poses a serious challenge in finding an effective remedy for cancer patients, because of the multitude of contributing factors influencing this complex phenomenon. One way to counter this problem is using a more targeted and dose-limiting approach for drug delivery, rather than relying on conventional therapies that exhibit multiple pernicious side-effects. Stability and specificity have traditionally been the core issues of peptide-based delivery vectors. In this study, we employed a structural regression modelling approach in the design, synthesis and characterization of a series of peptides that belong to approximately same topological cluster, yet with different electrostatic signatures encoded as a result of their differential positioning of amino acids in a given sequence. The peptides tagged with the fluorophore 5(6)-carboxyfluorescein, showed higher uptake in cancer cells with some of them colocalizing in the lysosomes. The peptides tagged with the anti-cancer drug methotrexate have displayed enhanced cytotoxicity and inducing apoptosis in triple-negative breast cancer cells. They also showed comparable uptake in side-population cells of lung cancer with stem-cell like properties. The most-optimized peptide showed accumulation in the tumor resulting in significant reduction of tumor size, compared to the untreated mice in in-vivo studies. Our results point to the following directives; (i) peptides can be design engineered for targeted delivery (ii) stereochemical engineering of peptide main chain can resist proteolytic enzymes and (iii) cellular penetration of peptides into cancer cells can be modulated by varying their electrostatic signatures.

Peptides as innovative strategies to combat drug resistance in cancer therapy

Drug resistance is the leading cause of treatment failure in patients with cancer. Thus, innovative therapeutic strategies are required to overcome this critical challenge and improve patient outcomes. In this review, we examine the potential of peptide-based therapies to combat drug resistance in cancer. We highlight the unique strategies and mechanisms that can be explored by using peptides, including their ability to selectively target tumours, facilitate drug delivery into cancer cells, and inhibit key intracellular proteins that drive cancer progression and resistance. Peptides offer a promising approach to overcoming both intrinsic and adaptative cancer resistance against chemotherapy, targeted therapies, and biologics.

Metabolism investigation of the peptide-drug conjugate LN005 in rats using UHPLCHRMS

LN005, as a peptide-drug conjugate (PDC), is a conjugate of the homing peptide VAP and doxorubicin (DOX). The exceptional targeting ability of the homing peptide VAP is directed toward glucose-regulated protein (GRP78), a highly expressed protein primarily found in the endoplasmic reticulum of various solid tumors. However, there are limited reports regarding the metabolism of peptide-drug conjugates (PDCs), and the in vivo metabolism of LN005 has yet to be investigated. After intravenous injection of 18 mg/kg LN005 in SD rats, biological samples including plasma, urine, fecal, and bile samples, were collected and analyzed by ultra-high performance liquid chromatography-high resolution mass spectrometry (UHPLC-HRMS). A total of 11 possible metabolites of LN005 were identified. Unchanged LN005 was found to be the main component in rat blood and urine, accounting for 46.46% and 63.79% of the total peak areas, respectively. M1057 was the most abundant metabolite in feces, accounting for 57.65% of the total peak area. Only one metabolite, M398, was identified in rat bile. The metabolism of LN005 is closely related to DOX, and the primary metabolic pathways involved oxidative deamination or hydrolysis, reductive glycosidic cleavage, hydrolytic glycosidic cleavage, and dehydrogenation.

Approaches for evaluation of novel CPP-based cargo delivery systems

Cell penetrating peptides (CPPs) can be broadly defined as relatively short synthetic, protein derived or chimeric peptides. Their most remarkable property is their ability to cross cell barriers and facilitate the translocation of cargo, such as drugs, nucleic acids, peptides, small molecules, dyes, and many others across the plasma membrane. Over the years there have been several approaches used, adapted, and developed for the evaluation of CPP efficacies as delivery systems, with the fluorophore attachment as the most widely used approach. It has become progressively evident, that the evaluation method, in order to lead to successful outcome, should concede with the specialties of the delivery. For characterization and assessment of CPP-cargo a combination of research tools of chemistry, physics, molecular biology, engineering, and other fields have been applied. In this review, we summarize the diverse, in silico, in vitro and in vivo approaches used for evaluation and characterization of CPP-based cargo delivery systems.