Synthesis and evaluation of squaramide and thiosquaramide inhibitors of the DNA repair enzyme SNM1A

Actinic keratosis (AKs) are part of the cancerization field, a region adjacent to AKs containing subclinical and histologically abnormal epidermal tissue due to Ultraviolet (UV)-induced DNA damage. The photoproducts as consequence of DNA damage induced by UV are mainly cyclobutane pyrimidine dimers (CPDs). Fernblock® demonstrated in previous studies significant reduction of the number of CPDs induced by UV radiation. Photolyases are a specific group of enzymes that remove the major UV-induced DNA lesions by a mechanism called photo-reactivation. A monocentric, prospective, controlled, and double blind interventional study was performed to evaluate the effect of a new medical device (NMD) containing a DNA-repair enzyme complex (photolyases, endonucleases and glycosilases), a combination of UV-filters, and Fernblock® in the treatment of the cancerization field in 30 AK patients after photodynamic therapy. Patients were randomized into two groups: patients receiving a standard sunscreen (SS) andpatients receiving the NMD. Clinical, dermoscopic, reflectance confocal microscopy (RCM) and histological evaluations were performed. An increase of AKs was noted in all groups after three months of PDT without significant differences between them (p=0.476). A significant increase in the number of AKs was observed in SS group after six (p=0.026) and twelve months of PDT (p=0.038); however, this increase did not reach statistical significance in the NMD group. Regarding RCM evaluation, honeycomb pattern assessment after twelve months of PDT showed significant differences in the extension and grade of the atypia in the NMD group compared to SS group (p=0.030 and p=0.026, respectively). Concerning histopathological evaluation, keratinocyte atypia grade improved from baseline to six months after PDT in all the groups, with no statistically significant differences between the groups. Twelve months after PDT, p53 expression was significantly lower in the NMD group compared to SS group (p=0.028). The product was well-tolerated, with no serious adverse events reported. Our results provide evidence of the utility of this NMD in the improvement of the cancerization field and in the prevention of the development of new AKs.

Download Full-text

Faculty Opinions recommendation of DNA polymerase lambda, a novel DNA repair enzyme in human cells.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1005644.66906 ◽

2002 ◽

Author(s):

Errol C Friedberg

Keyword(s):

Dna Repair ◽

Dna Polymerase ◽

Human Cells ◽

Repair Enzyme

Download Full-text

The Development of Tyrosyl-DNA Phosphodyesterase 1 (TDP1) Inhibitors Based on the Amines Combining Aromatic/Heteroaromatic and Monoterpenoid Moieties

Letters in Drug Design & Discovery ◽

10.2174/1570180816666181220121042 ◽

2019 ◽

Vol 16 (5) ◽

pp. 597-605 ◽

Cited By ~ 1

Author(s):

Evgenii Mozhaitsev ◽

Evgenii Suslov ◽

Yuliya Demidova ◽

Dina Korchagina ◽

Konstantin Volcho ◽

...

Keyword(s):

Dna Repair ◽

Tumor Cell ◽

13C Nmr ◽

Inhibitory Activity ◽

Secondary Amines ◽

Repair Enzyme ◽

1H And 13C Nmr ◽

Chemical Structures ◽

Natural Substances ◽

Micromolar Range

Background: Inhibition of the DNA repair enzyme, tyrosyl-DNA phosphodiesterase 1 (TDP1), may increase the efficacy of cancer drugs that cause damage to tumor cell DNA. Among the known TDP1 inhibitors, there are compounds containing moieties of natural substances, e.g., monoterpenoids. In this work, we synthesized several compounds containing aromatic/ heteroaromatic amines and monoterpenoid groups and assessed their TDP1 inhibition potential. Methods: Structures of all the synthesized compounds were confirmed by 1H and 13C NMR as well as HRMS. The TDP1 inhibitory activity of the amines was determined by real-time fluorescence oligonucleotide biosensor. Results: The synthesized secondary amines had TDP1 inhibitory activity IC50 in the range of 0.79-9.2 µM. The highest activity was found for (–)-myrtenal derivatives containing p-bromoaniline or m-(trifluoromethyl)aniline residue. Conclusion: We synthesized 22 secondary amines; of these, 17 amines are novel chemical structures. Many of the amines inhibit TDP1 activity in the low micromolar range. Therefore, these compounds are promising for further study of their antiproliferative activity in conjunction with DNA damaging drugs.

Download Full-text