The DNA damage response (DDR) network and the mitogen-activated protein kinase (MAPK) signaling pathway are crucial mechanisms for the survival of all living beings. An accumulating body of evidence suggests that there is crosstalk between these two systems, thus favoring the appropriate functioning of multi-cellular organisms. On the other hand, aberrations within these mechanisms are thought to play a vital role in the onset and progression of several diseases, including cancer, as well as in the emergence of drug resistance. Here, we provide an overview of the current knowledge regarding alterations in the DDR machinery and the MAPK signaling pathway as well as abnormalities in the DDR/MAPK functional crosstalk in multiple myeloma, the second most common hematologic malignancy. We also present the latest advances in the development of anti-myeloma drugs targeting crucial DDR- and MAPK-associated molecular components. These data could potentially be exploited to discover new therapeutic targets and effective biomarkers as well as for the design of novel clinical trials. Interestingly, they might provide a new approach to increase the efficacy of anti-myeloma therapy by combining drugs targeting the DDR network and the MAPK signaling pathway.

The importance of herbal extracts on health, which was initially based on ethnopharmacological and traditional knowledge, becomes increasingly well documented by numerous experimental and intervention studies. The daily use of beverages from different aromatic plants which becomes more popular nowadays, has been a tradition in Crete, and a habit that has been linked to the longevity seen in the island. Additionally, a certain combination of aromatic plants has been used against common cold and influenza. Interestingly, when such a mixture of essential oils from Cretan herbs (Cretan Aromatic Plants essential oil, CAPeo, from thyme, Greek sage, and Cretan dittany) was formulated, significant antiviral properties were observed in vitro and a significant reduction in the duration and severity of symptoms of patients with upper respiratory tract infections was found in a clinical study. However, since many plants extracts can exert toxic effects, toxicity issues should be properly addressed. In the present work we present an acute and sub-chronic toxicity evaluation for this mixture of aromatic plants’ essential oils in rats. In fact, it is the only toxicity study for Cretan dittany. We report absence of toxicity, rendering the use of the mixture of essential oils from Cretan dittany, Greek sage and thyme as safe.

The DNA Damage Response (DDR) network and the mitogen-activated protein kinase (MAPK) signaling pathway are crucial mechanisms for the survival of all living beings. An accumulating body of evidence suggests that there is a crosstalk between these two systems, thus favoring the appropriate functioning of multi-cellular organisms. On the other hand, aberrations within these mechanisms are thought to play a vital role in the onset and progression of several diseases, including cancer, as well as in the emergence of drug resistance. Here, we provide an overview of the current knowledge regarding alterations in the DDR machinery and the MAPK signaling pathway, as well as abnormalities in the DDR-MAPK functional crosstalk in multiple myeloma, the second most common hematologic malignancy. We also present the latest advances in the development of anti-myeloma drugs targeting crucial DDR- and MAPK-associated molecular components. These data could potentially be exploited to discover new therapeutic targets and effective biomarkers, as well as for the design of novel clinical trials. Interestingly, they might provide a new approach to increase the efficacy of anti-myeloma therapy by combining drugs targeting the DDR network and the MAPK signaling pathway.

Background/Objectives: Non-small cell lung cancer (NSCLC) is the most frequent type of lung cancer, and its main treatments include chemotherapy with genotoxic drugs and immunotherapy. Central to the cellular response to genotoxic stress is the DNA damage response (DDR) network, regulated by key kinases such as ataxia-telangiectasia mutated and Rad3-related (ATR). Herein, we tested the hypothesis that inhibition of ATR enhances the cytotoxicity of genotoxic agents and the antitumor immune response. Methods: DDR-related parameters and redox status, expressed as GSH/GSSG ratio, and apurinic/apyrimidinic lesions, were evaluated in human (A549, H1299) and murine (LLC) NSCLC cell lines after co-exposure to ATR inhibitor (AZD6738) and ultraviolet C (UVC) irradiation or cisplatin. Using a syngeneic LLC model, treatments of AZD6738 alone or in combination with cisplatin and/or anti-programmed cell death 1 antibody (anti-PD1) were examined. Results: In all cell lines, combined treatment with AZD6738 and cisplatin or UVC irradiation markedly decreased cell viability, DNA repair efficiency, and GSH/GSSG ratios; increased drug-induced DNA damage; and augmented apurinic/apyrimidinic lesions. In vivo, following treatment with AZD6738 and cisplatin, flow cytometry analysis performed in tumor cells revealed an increased infiltration of CD3⁺ and CD8⁺ T cells, with the triple combination of AZD6738, cisplatin, and anti-PD1 achieving the strongest antitumor effect. The CD3⁺CD4⁻CD8⁻ double-negative (DN) T cell population in tumor samples also emerged as a contributing factor in this context. Conclusions: These results demonstrate that ATR blockade concurrently enhances the efficacy of genotoxic agents and immune checkpoint inhibitors, thus paving the way for combination therapies in NSCLC.

The DNA Damage Response (DDR) network is an essential machinery for maintaining genomic integrity, with DDR defects being implicated in cancer initiation, progression and treatment resistance. Moreover, oxidative stress, an imbalance between reactive oxygen species production and antioxidant defence, can significantly impact cell viability, leading to cell death or survival. Herein, we tested the hypothesis that DDR-related signals and oxidative stress status measured in multiple myeloma (MM) cell lines correlate with the sensitivity to genotoxic insults. In a panel of eleven human MM cell lines and one healthy B lymphoblastoid cell line, oxidative stress, apurinic/apyrimidinic sites and DDR-related parameters, including endogenous/baseline DNA damage, critical DNA repair mechanisms, chromatin condensation and apoptosis rates were evaluated. We found that MM cell lines with increased apoptosis rates displayed significantly higher levels of endogenous/baseline DNA damage, increased oxidative stress and apurinic/apyrimidinic lesions, decreased nucleotide excision repair and interstrand crosslinks repair capacities and highly condensed chromatin structure. Taken together, these findings demonstrate that DDR-related parameters and redox status correlate with the sensitivity of MM cells to DNA damaging agents and, if further validated, may be exploited as novel therapeutic targets and sensitive/effective biomarkers.

The DNA Damage Response (DDR) network is an essential machinery for maintaining genomic integrity, with DDR defects being implicated in cancer initiation, progression, and treatment resistance. Moreover, oxidative stress, an imbalance between reactive oxygen species production and antioxidant defense, can significantly impact cell viability, leading to cell death or survival. Herein, we tested the hypothesis that DDR-related signals and redox status measured in multiple myeloma (MM) cell lines correlate with the sensitivity to genotoxic insults. At baseline and following irradiation with Ultraviolet C (UVC; 50 J/m²) or treatment with melphalan (100 μg/mL for 5 min) DDR-related parameters, redox status expressed as GSH/GSSG ratio and apurinic/apyrimidinic sites were evaluated in a panel of eleven human MM cell lines and one healthy B lymphoblastoid cell line. We found that MM cell lines with increased apoptosis rates displayed significantly higher levels of endogenous/baseline DNA damage, reduced GSH/GSSG ratio, augmented apurinic/apyrimidinic lesions, decreased nucleotide excision repair and interstrand crosslinks repair capacities, and highly condensed chromatin structure. Taken together, these findings demonstrate that DDR-related parameters and redox status correlate with the sensitivity of MM cells to DNA-damaging agents, specifically melphalan, and, if further validated, may be exploited as novel sensitive/effective biomarkers.