Moderate intermittent negative pressure increases invasiveness of MDA-MB-231 triple negative breast cancer cells

Negative-Pressure Wound Therapy: What We Know and What We Need to Know

Negative-pressure wound therapy (NPWT) promotes wound healing by applying negative pressure to the wound surface. A quarter of a century after its introduction, NPWT has been used in various clinical conditions, although molecular biological evidence is insufficient due to delay in basic research. Here, we have summarized the history of NPWT, its mechanism of action, what is currently known about it, and what is expected to be known in the future. Particularly, attention has shifted from the four main mechanisms of NPWT to the accompanying secondary effects, such as effects on various cells, bacteria, and surgical wounds. This chapter will help the reader to understand the current status and shortcomings of NPWT-related research, which could aid in the development of basic research and, eventually, clinical use with stronger scientific evidence.

A bioreactor for studying negative pressure wound therapy on skin grafts

Negative pressure wound therapy (NPWT) has become the prevailing standard of care for treating complex soft tissue wounds and is now being considered for use in alternative applications including improving skin graft take. While it is generally agreed that negative pressure leads to improved wound healing, universal consensus on its optimal application is not supported in the literature. We describe the design and validation of a bioreactor to determine the prospective benefits of NPWT on skin grafts and engineered skin substitutes (ESS). Clinically relevant pressures were applied, and the native human skin was able to withstand greater negative pressures than the engineered substitutes. Both skin types were cultured under static, flow‐only, and −75 mm Hg conditions for 3 days. While it remained intact, there was damage to the epidermal‐dermal junction in the ESS after application of negative pressure. The normal skin remained viable under all culture conditions. The engineered skin underwent apoptosis in the flow‐only group; however, the application of negative pressure reduced apoptosis. Vascular endothelial growth factor levels were significantly higher in the normal flow‐only group, 152.0 ± 75.1 pg/mg protein, than the other culture conditions, 81.6 ± 35.5 pg/mg for the static and 103.6 ± pg/mg for the negative pressure conditions. The engineered skin had a similar trend but the differences were not significant. This bioreactor design can be used to evaluate the impacts of NPWT on the anatomy and physiology of skin to improve outcomes in wounds after grafting with normal or engineered skin.

Extracts of Bridelia ovata and Croton oblongifolius induce apoptosis in human MDA‑MB‑231 breast cancer cells via oxidative stress and mitochondrial pathways

Breast cancer is the most common type of cancer and is also the second leading cause of cancer‑associated death in women worldwide. Thus, there is an urgent requirement for the development of effective treatments for this disease. Bridelia ovata and Croton oblongifolius are herbs used in Thai traditional medicine that have been used to treat various health problems; B. ovata has traditionally been used as a purgative, an antipyretic, a leukorrhea treatment and as a birth control herb. C. oblongifolius has been used to increase breast milk production, for post‑partum care (where it is used as a hot bath herb), and as a treatment for flat worms and dysmenorrhea. However, there is little research investigating the anticancer properties of these herbs. The present study aimed to investigate the anticancer properties of crude ethyl acetate extracts of B. ovata (BEA) and C. oblongifolius (CEA) in order to explore their underlying mechanisms in breast cancer cell death. The phytoconstituents of the crude extracts of BEA and CEA were studied using gas chromatography‑mass spectrometry (GC‑MS). GC‑MS analysis showed that the primary compound in BEA is friedelan‑3‑one, and kaur‑16‑en‑18‑oic acid in CEA. Cytotoxicity was investigated using an MTT assay, both BEA and CEA showed greater toxicity against MDA‑MB‑231 breast cancer cells compared with their effect on MCF10A normal epithelial mammary cells. BEA and CEA exerted various effects, including inducing apoptotic cell death, reducing mitochondrial transmembrane potential, increasing the levels of intracellular ROS, activating caspases, upregulating pro‑apoptotic and downregulating anti‑apoptotic genes and proteins. BEA and CEA were shown to have anticancer activity against breast cancer cells and induce apoptosis in these cells via a mitochondrial pathway and oxidative stress.

Remotely Phototriggered, Transferrin-Targeted Polymeric Nanoparticles for the Treatment of Breast Cancer

Triple-negative breast cancer (TNBC) has the worst prognosis among all subtypes of breast cancer. Currently, no targeted treatment has been approved for TNBC. The goal of this study was to design a remotely triggered, targeted therapy for TNBC using polymeric nanoparticles and light. Active targeting of TNBC was achieved by conjugating the nanoparticles to a peptide (hTf) that binds to the transferrin receptor, which is overexpressed in TNBC. Photodynamic therapy (PDT) was explored for TNBC treatment by remotely triggering benzoporphyrin derivative monoacid (BPD), a photosensitizer, using near-infrared light. In this study, we investigated the use of actively targeting polymeric nanoparticles for PDT against TNBC using in vitro imaging and cytotoxicity studies. Fluorescence imaging confirmed that the BPD-loaded nanoparticles showed greater fluorescence in TNBC cells compared to free BPD, but more importantly, actively targeted nanoparticles displayed stronger fluorescence compared to passively targeted nanoparticles. Moreover, fluorescence imaging following competition with empty targeted nanoparticles validated the specificity of the targeted nanoparticles for TNBC cells. The PDT killing results were in line with the fluorescence imaging results, where actively targeting nanoparticles exhibited the highest phototriggered cytotoxicity in TNBC cells, making them an attractive nanoplatform for TNBC treatment.