Detection of a new reaction by-product in BDDE cross-linked autoclaved hyaluronic acid hydrogels by LC-MS analysis.

BACKGROUND: Hyaluronic acid (HA), a naturally occurring polysaccharide, is used in the production of dermal fillers for esthetic purposes. As it has a few days of half-life in human tissues, HA-based dermal filler is chemically modified to increase its lifetime in the body. The most common modification used in commercial HA-based filler is the cross-linking of HA chains using 1,4-butanediol diglycidyl ether (BDDE) as cross-linking agent. Residual, or unreacted, BDDE is considered nontoxic when it is <2 parts per million (ppm); therefore, the quantification of residual BDDE in the final dermal filler is mandatory to ensure the safety of the patients. MATERIALS AND METHODS: The present study describes the detection and characterization of one by-product of the cross-linking reaction between BDDE and HA in alkaline conditions by combining both liquid chromatography and mass spectroscopy (LC-MS). RESULTS: After different analyses, it was found that the alkaline conditions and the high temperatures employed to sterilize the HA-BDDE hydrogel promote the formation of this new by-product, a "propene glicol-like" compound. LC-MS analysis confirmed that this by-product have the same monoisotopic mass as that of BDDE, a different retention time (tR), and also a different UV absorbance (λ=200 nm) pattern. Unlike BDDE, it was observed in the LC-MS analysis that this by-product had a higher detection at 200 nm in the same assay conditions. CONCLUSION: These results suggest that this new compound does not have an epoxide on its structure. The discussion is open to assess the risk of this new by-product found in the production of HA-BDDE hydrogels (HA dermal fillers) for commercial purposes.

In vitro study of RRS® Silisorg CE Class III medical device composed of silanol: effect on human skin fibroblasts and its clinical use.

INTRODUCTION: Silanol (organic silicon) has been used for decades in the treatment of skin photoaging as it stabilizes and maintains skin structures through hydrogen bonding electrostatic interaction with extracellular matrix (ECM) proteins or glycosaminoglycans. Organic silicon-based products are often presented as silanol derivatives which are currently associated to other structural molecules such as orthohydroxybenzoate, carboxymethyl theophylline alginate, ascorbate, acetyltyrosine, sodium lactate or mannuronate. Consequently, organic silicon formulations may differ substantially between the medical devices available on the market, which may result in additional effect on the skin. Therefore, there is a real need for a better characterization of the products in terms of their action on human skin and in vitro skin model. MATERIALS AND METHODS: In this in vitro study, the effect of RRS® Silisorg was analyzed. RRS® Silisorg is a dermal implant (CE Class III medical device) containing monomethylsilanol mannuronate associated to an antioxidant resveratrol. Skin fibroblast viability and capacity to induce the production of key ECM genes were evaluated in the presence of different concentrations of RRS® Silisorg. The key ECM genes selected were collagen type I, elastin and hyaluronan synthase type 2 (HAS2), which is the cellular enzyme responsible for high-molecular weight hyaluronic acid (HA) production. Viability was evaluated through 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and expression was quantified by quantitative polymerase chain reaction. RESULTS: RRS® Silisorg increased fibroblast gene expression of HAS2 in the first 24 hours, 25 times in the presence of 1 mg/mL of solution, followed by a collagen type I gene expression (4.7 times) and elastin expression (2.5 times) increase after 48 hours. CONCLUSION: These results demonstrate that the silanol-based medical device RRS® Silisorg sustains HA, collagen and elastin production in human skin fibroblasts in vitro.

Quantification of Pathway Cross-talk Reveals Novel Synergistic Drug Combinations for Breast Cancer.

Combinatorial therapeutic approaches are an imperative to improve cancer treatment, because it is critical to impede compensatory signaling mechanisms that can engender drug resistance to individual targeted drugs. Currently approved drug combinations result largely from empirical clinical experience and cover only a small fraction of a vast therapeutic space. Here we present a computational network biology approach, based on pathway cross-talk inhibition, to discover new synergistic drug combinations for breast cancer treatment. In silico analysis identified 390 novel anticancer drug pairs belonging to 10 drug classes that are likely to diminish pathway cross-talk and display synergistic antitumor effects. Ten novel drug combinations were validated experimentally, and seven of these exhibited synergy in human breast cancer cell lines. In particular, we found that one novel combination, pairing the estrogen response modifier raloxifene with the c-Met/VEGFR2 kinase inhibitor cabozantinib, dramatically potentiated the drugs' individual antitumor effects in a mouse model of breast cancer. When compared with high-throughput combinatorial studies without computational prioritization, our approach offers a significant advance capable of uncovering broad-spectrum utility across many cancer types. Cancer Res; 77(2); 459-69. ©2016 AACR.

In vitro study of RRS HA injectable mesotherapy/biorevitalization product on human skin fibroblasts and its clinical utilization.

Mesotherapy/biorevitalization with hyaluronic acid (HA) is a treatment approach currently used for skin rejuvenation. Various products with a wide range of polycomponent formulations are available on the market. Most of these formulations contain noncross-linked HA in combination with a biorevitalization cocktail, formed by various amounts of vitamins, minerals, amino acids, nucleotides, coenzymes, and antioxidants. Although ingredients are very similar among the different products, in vitro and clinical effects may vary substantially. There is a real need for better characterization of these products in terms of their action on human skin or in vitro skin models. In this study, we analyzed the effect of the RRS(®) (Repairs, Refills, Stimulates) HA injectable medical device on human skin fibroblasts in vitro. Skin fibroblast viability and its capacity to induce the production of key extracellular matrix were evaluated in the presence of different concentrations of RRS HA injectable. Viability was evaluated through colorimetric MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide) assay, and key extracellular matrix genes, type I collagen and elastin, were quantified by quantitative polymerase chain reaction. Results demonstrated that RRS HA injectable could promote human skin fibroblast viability (+15%) and increase fibroblast gene expression of type I collagen and elastin by 9.7-fold and 14-fold in vitro, respectively. These results demonstrate that mesotherapy/biorevitalization products can, at least in vitro, effectively modulate human skin fibroblasts.

Systematic identification of molecular links between core and candidate genes in breast cancer.

Despite the remarkable progress achieved in the identification of specific genes involved in breast cancer (BC), our understanding of their complex functioning is still limited. In this manuscript, we systematically explore the existence of direct physical interactions between the products of BC core and associated genes. Our aim is to generate a protein interaction network of BC-associated gene products and suggest potential molecular mechanisms to unveil their role in the disease. In total, we report 599 novel high-confidence interactions among 44 BC core, 54 BC candidate/associated and 96 newly identified proteins. Our findings indicate that this network-based approach is indeed a robust inference tool to pinpoint new potential players and gain insight into the underlying mechanisms of those proteins with previously unknown roles in BC. To illustrate the power of our approach, we provide initial validation of two BC-associated proteins on the alteration of DNA damage response as a result of specific re-wiring interactions. Overall, our BC-related network may serve as a framework to integrate clinical and molecular data and foster novel global therapeutic strategies.

Breast cancer genes PSMC3IP and EPSTI1 play a role in apoptosis regulation.

A key element to delineate the biology of individual tumors is the regulation of apoptosis. In this work, we functionally characterize two breast cancer associated genes, the proteasome 26S subunit ATPase 3 interacting protein (PSMC3IP) and the epithelial-stromal interaction 1 (EPSTI1), to explore their potential apoptotic role in breast cancer. We first explore the existence of direct physical interactions with annotated BC-apoptotic genes. Based on the generated interaction network, we examine several apoptotic markers to determine the effect of PSMC3IP and EPSTI1 gene expression modulation in two different human breast cancer cell lines to suggest potential molecular mechanisms to unveil their role in the disease. Our results show that PSMC3IP and EPSTI1 are able to modulate the extrinsic apoptotic pathway in estrogen receptor positive and triple negative breast cancer cell lines, highlighting them as potential therapeutic targets.

Charting the molecular links between driver and susceptibility genes in colorectal cancer.

Despite significant advances in the identification of specific genes and pathways important in the onset and progression of colorectal cancer (CRC), mechanistic insight into the relationship between driver and susceptibility genes is needed. In this paper, we systematically explore physical interactions between causative and putative CRC susceptibility genes to reveal the molecular mechanisms involved in tumor biology. In total, we identify 622 high-confidence protein-protein interactions between 42 CRC causative and 65 candidate susceptibility genes. Among the latter, 28 are located in the CRCS9 loci, related to the etiology of CRC, and 17 are co-expressed with well-established CRC drivers, which makes them excellent candidates for further functional studies. Moreover, we find a high degree of functional coherence between connected driver and susceptibility genes, which indicates that our network-based strategy is useful to gain insight into the underlying mechanisms of those proteins with unknown roles in CRC.