Antiproliferative effects of a new α-lipoic acid derivative, DHL-HisZnNa, in HT29 human colon cancer cellsin vitro

Review of lipoic acid: From a clinical therapeutic agent to various emerging biomaterials

Lipoic acid (LA), an endogenous small molecule in organisms, has been extensively used for the highly efficient clinical treatment of malignant diseases, which include diabetes, Alzheimer's disease, and cancer over the past seven decades. Tremendous progresses have been made on the use of LA in nanomedicine for the development of various biomaterials because of its unique biological properties and highly adaptable structure since the first discovery. However, there are few reviews thus far, to our knowledge, summarizing this hot subject of research of LA and its derived biomaterials. For this purpose, we present herein the first comprehensive summary on the design and development of LA and its derived materials for biomedical applications. This review first discusses the therapeutic use of LA followed by the description of synthesis and preclinical study of LA-derived-small molecules. The applications of various LA and poly (lipoic acid) (PLA)-derived-biomaterials are next summarized in detail with an emphasis on the use of LA for the design of biomaterials and the diverse properties. This review describes the development of LA from a clinical therapeutic agent to a building unit of various biomaterials field, which will promote the further discovery of new therapeutic uses of LA as therapeutic agents and facile development of LA-based derivates with greater performance for biomedical applications.

Emerging chemical scaffolds with potential SHP2 phosphatase inhibitory capabilities - A comprehensive review

The drug discovery panorama is cluttered with promising therapeutic targets that have been deserted because of inadequate authentication and screening failures. Molecular targets formerly tagged as "undruggable" are nowadays being more cautiously cross-examined, and whilst they stay intriguing, numerous targets are emerging more accessible. Protein tyrosine phosphatases (PTPs) excellently exemplifies a class of molecular targets that have transpired as druggable, with several small molecules and antibodies recently turned available for further development. In this respect, SHP2, a PTP, has emerged as one of the potential targets in the current pharmacological research, particularly for cancer, due to its critical role in various signalling pathways. Recently, few molecules with excellent potency have entered clinical trials, but none could reach the clinic. Consequently, search for novel, non-toxic, and specific SHP2 inhibitors are on purview. In this review, general aspects of SHP2 including its structure and mechanistic role in carcinogenesis have been presented. It also sheds light on the development of novel molecular architectures belonging to diverse chemical classes that have been proposed as SHP2-specific inhibitors along with their structure-activity relationships (SARs), stemming from chemical, mechanism-based and computer-aided studies reported since January 2015 to July 2020 (excluding patents), focusing on their potency and selectivity. The encyclopedic facts and discussions presented herein will hopefully facilitate researchers to design new ligands with better efficacy and selectivity against SHP2.

Lipoic acid-induced oxidative stress abrogates IGF-1R maturation by inhibiting the CREB/furin axis in breast cancer cell lines

The beneficial effects of lipoic acid (LA) in cancer treatment have been well documented in the last decade. Indeed, LA exerts crucial antiproliferative effects by reducing breast cancer cell viability, cell cycle progression and the epithelial-to-mesenchymal transition (EMT). However, the mechanisms of action (MOA) underlying these antiproliferative effects remain to be elucidated. Recently, we demonstrated that LA decreases breast cancer cell proliferation by inhibiting IGF-1R maturation via the downregulation of the proprotein convertase furin. The aim of the present study was to investigate the MOA by which LA inhibits furin expression in estrogen receptor α (ERα) (+) and (-) breast cancer cell lines. We unveil that LA exerts a pro-oxidant effect on these cell lines, the resulting reactive oxygen species (ROS) generated being responsible for the reduction in the expression of the major (CREB) protein. This transcription factor is overexpressed in many types of cancers and regulates the expression of furin in breast cancer cells independently of ERα, as evidenced herein by the inhibition of furin expression following CREB silencing. Consequently, our findings expose for the first time the complete MOA of LA via the CREB/furin axis leading to inhibition of breast cancer cell proliferation.

The utility of DHL-HisZnNa, a novel antioxidant, against anticancer agent-induced alopecia in breast cancer patients: a multicenter phase II clinical trial

PURPOSE

Chemotherapy-induced alopecia (CIA) is a distressing adverse effect of anticancer drugs; however, there are currently no mechanisms to completely prevent CIA. In this study, we performed a clinical trial to examine whether sodium N-(dihydrolipoyl)-l-histidinate zinc complex (DHL-HisZnNa), an alpha-lipoic acid derivative, prevents CIA in patients with breast cancer.

METHODS

Between July 2014 and May 2015, we performed a multi-center, single arm, clinical trial involving 103 breast cancer patients who received adjuvant chemotherapy at three medical institutions in Japan. During chemotherapy, a lotion containing 1% DHL-HisZnNa was applied daily to the patients' scalps. The primary endpoint was the incidence of grade 2 alopecia; the secondary endpoints were the duration of grade 2 alopecia, alopecia-related symptoms, and drug-related adverse events. Alopecia was evaluated by three independent reviewers using head photographs taken from four angles.

RESULTS

Safety analysis was performed for 101 patients who started the protocol therapy. After excluding one patient who experienced disease progression during treatment, 100 patients who received at least two courses of chemotherapy underwent efficacy analysis. All original 101 patients developed grade 2 alopecia, the median durations of which were 119 days (112-133 days) and 203 days (196-212 days) in the groups treated with four and eight courses of chemotherapy, respectively. Mild or moderate adverse events potentially related to DHL-HisZnNa were observed in 11 patients. Alopecia-related symptoms were observed in 53 patients (52%).

CONCLUSIONS

The application of 1% DHL-HisZnNa to the scalp did not prevent CIA. However, this drug may promote recovery from CIA.

TRIAL REGISTRATION NUMBER

UMIN000014840.

An α-Lipoic acid derivative, and anti-ROS agent, prevents the acquisition of multi-drug resistance in clinical isolates of Pseudomonas aeruginosa

Pseudomonas aeruginosa is one of the most common causes of nosocomial infections, and its multi-drug resistance has been a serious problem worldwide. The aim of this study was to evaluate whether exposure to piperacillin and reactive oxygen species (ROS) could lead to multi-drug resistance for clinical isolates of P. aeruginosa. The inhibition of this acquired resistance by the anti-ROS agent was also examined. In vitro inducement of multi-drug resistance was performed against 20 clinical isolates. These strains were incubated for 24 h and transferred 5 times after being exposed to 1 mM H₂O₂ (ROS) in addition to a sub-MIC of piperacillin by the agar dilution method. Each MIC of piperacillin and levofloxacin was determined. As the mechanism of levofloxacin resistance, mutation of QRDR was investigated. The expression level of genes encoding efflux pumps; mexA, mexY, mexC, and D2 porin; oprD were determined by real-time PCR. Multi-resistance to both piperacillin and levofloxacin was induced with 4 of 20 strains (20%). No amino acid change was confirmed in QRDR. These strains showed overexpression of mexA, mexY, mexC, and another one showed decrease of oprD expression. Resistance development in 4 strains was inhibited by the same method including the anti-ROS agent, sodium zinc histidine dithiooctanamide (DHL-His-Zn). In conclusion, stimulation by ROS promoted acquisition of multi-drug resistance in 20% of isolates of P. aeruginosa, and DHL-His-Zn completely inhibited this acquisition of resistance. Therefore, this anti-ROS agent may be useful to assist antimicrobial chemotherapy by preventing multi-drug resistance.

Therapeutic potential of α-lipoic acid derivative, sodium zinc histidine dithiooctanamide, in a mouse model of allergic rhinitis

BACKGROUND

Oxidative stress is involved in various diseases, including allergies. Several studies have pointed to the preventive and therapeutic potential of antioxidants in allergic disorders. However, little is known about the immunomodulatory effects of antioxidants in type I hypersensitivity. In this study we aimed to explore the impact of a water-soluble antioxidant and α-lipoic acid derivative, sodium zinc histidine dithiooctanamide (DHL-HisZn), on mast-cell- and T-cell-mediated allergic and immune responses both in vitro and in vivo.

METHODS

The therapeutic impact of DHL-HisZn on mast-cell-mediated type I hypersensitivity was evaluated by a mast-cell degranulation assay using bone marrow-derived mast cells and by a mouse model of ovalbumin (OVA)-induced allergic rhinitis. The effect of DHL-HisZn on the proportion of regulatory T cells (Tregs) was evaluated using flow cytometry.

RESULTS

During the course of OVA-induced allergic rhinitis in mice, serum nitrate was elevated, suggesting the involvement of oxidative stress in allergic responses. DHL-HisZn not only suppressed mast-cell degranulation but also ameliorated OVA-induced nasal hypersensitivity, with significant suppression of serum nitrate. DHL-HisZn treatment significantly suppressed OVA-specific immunoglobulin E (IgE) but enhanced OVA-specific IgG2a in OVA-sensitized and nasal-challenged mice. Furthermore, DHL-HisZn treatment suppressed interleukin-17 production in OVA-stimulated splenocytes. Finally, we demonstrated the induction of Tregs by DHL-HisZn in concanavalin A blasts.

CONCLUSIONS

These findings suggest that DHL-HisZn may regulate mast-cell-, T-helper 2 (Th2)-, and Th17-mediated allergic and immune responses by induction of Tregs.

The alpha-lipoic acid derivative DHLHZn: a new therapeutic agent for acute lung injury in vivo

OBJECTIVE AND DESIGN

An animal experiment was performed to demonstrate the anti-inflammatory effects of an alpha-lipoic acid (ALA) derivative, dihydrolipoyl histidinate zinc complex (DHLHZn) for acute lung injury (ALI) and to investigate the mechanism of action.

MATERIAL

Rats were randomly divided into three experimental groups: control group (n = 17), DHLHZn(-) group (n = 11, ALI model rats), and DHLHZn(+) group (n = 12, ALI model rats treated by DHLHZn).

TREATMENT

Lipopolysaccharides (LPS, 10 mg/kg) were administered intratracheally in the DHLHZn(-) group and the DHLHZn(+) group. For the DHLHZn(+) group, DHLHZn (100 mg/kg) was administered intraperitoneally 2 h prior to LPS administration.

METHODS

Four hours after LPS administration, bronchoalveolar lavage fluid (BALF) and lung tissue were collected. The findings were analyzed using the Mann-Whitney U test.

RESULTS

Total number of cells, number of neutrophils and lymphocytes, levels of various inflammatory cytokines, and NF-kB p65 concentration of BALF were significantly lower in the DHLHZn(+) group than in the DHLHZn(-) group (p < 0.05). ALI pathology scores were significantly lower in the DHLHZn(+) group than in the DHLHZn(-) group (p < 0.001).

CONCLUSIONS

Anti-inflammatory effects of DHLHZn for ALI were demonstrated by BALF and histopathological findings. The mechanism of action of DHLHZn was considered to be via inhibition of the NF-kB signaling pathway. DHLHZn is thus suggested to be a new prophylactic agent for ALI.

Effect of the new synthetic vitamin E derivative ETS-GS on radiation enterocolitis symptoms in a rat model

Radiation enterocolitis is a severe adverse event that occurs after radiotherapy for malignant abdominal tumors. In this study, the therapeutic effects of ETS-GS, a novel vitamin E derivative with antioxidative and anti-inflammatory abilities, were examined in a rat model of radiation enterocolitis. The radiation enterocolitis model was created by irradiation of male rats with a single dose of 10 Gy. ETS-GS was administered subcutaneously (10 mg/kg/day) for five consecutive days from two days prior to irradiation. The animals were sacrificed three days after irradiation; following which, ileal tissue samples were analyzed for macroscopic and histological findings, presence of apoptosis, degree of oxidative stress and inflammation. In the irradiated group, severe erosion was observed in the small intestine in addition to necrosis of the mucosal layer, swelling and invasion of inflammatory cells of the submucosal layer, and shortening of the crypts. In irradiated rats that received ETS-GS, mucosal injury in the small intestine was milder compared with that of irradiated rats that received no ETS-GS. In addition, ETS-GS decreased apoptosis in the small intestine and reduced the activity of myeloperoxidase and malondialdehyde, which are markers for inflammation and oxidative stress. ETS-GS with antioxidant activity has a therapeutic effect on the symptoms of radiation enterocolitis in a rat model.

Involvement of multiple cell cycle aberrations in early preneoplastic liver cell lesions by tumor promotion with thioacetamide in a two-stage rat hepatocarcinogenesis model

Thioacetamide (TAA) induces oxidative stress and hepatocarcinogenicity in rats. We previously reported that TAA promotion caused various disruptions in cell cycle protein expression in rats, including downregulation of p16(Ink4a), which is associated with intraexonic hypermethylation in hepatocellular proliferative lesions. This study further investigated the contribution of cell cycle aberrations associated with early hepatocarcinogenic processes induced by TAA using antioxidants, enzymatically modified isoquercitrin (EMIQ) and α-lipoic acid (ALA), in a two-stage rat hepatocarcinogenesis model. TAA-promotion after initiation with N-diethylnitrosamine increased the number and area of hepatocellular foci immunoreactive for glutathione S-transferase placental form (GST-P) and the numbers of proliferating and apoptotic cells. Co-treatment with EMIQ and ALA suppressed these increases. TAA-induced formation of p16(Ink4a-) foci in concordance with GST-P(+) foci was not suppressed by co-treatment with EMIQ or ALA. TAA-promotion increased cellular distributions of cell proliferation marker Ki-67, G2/M and spindle checkpoint proteins (phosphorylated checkpoint kinase 1 and Mad2), the DNA damage-related protein phosphorylated histone H2AX, and G2-M phase-related proteins (topoisomerase IIα, phosphorylated histone H3 and Cdc2) within GST-P(+) foci, and co-treatment with EMIQ or ALA suppressed these increases. These results suggest that downregulation of p16(Ink4a) may allow selective proliferation of preneoplastic cells by TAA promotion. However, antioxidants did not counteract this gene control. Moreover, effective suppression of TAA-induced cellular population changes within preneoplastic lesions by antioxidants may reflect facilitation of cell cycling and accumulation of DNA damage causing the activation of cell cycle checkpoints, leading to G2 and M phase arrest at the early stages of hepatocarcinogenesis promoted by TAA.