No abstract

Recently, we have experienced a serious pandemic. Despite significant technological advances in molecular technologies, it is very challenging to slow down the infection spread. It appeared that due to globalization, SARS-CoV-2 spread easily and adapted to new environments or geographical or weather zones. Additionally, new variants are emerging that show different infection potential and clinical outcomes. On the other hand, we have some experience with other pandemics and some solutions in virus elimination that could be adapted. This is of high importance since, as the latest reports demonstrate, vaccine technology might not follow the new, mutated virus outbreaks. Thus, identification of novel strategies and markers or diagnostic methods is highly necessary. For this reason, we present some of the latest views on SARS-CoV-2/COVID-19 therapeutic strategies and raise a solution based on miRNA. We believe that in the face of the rapidly increasing global situation and based on analogical studies of other viruses, the possibility of using the biological potential of miRNA technology is very promising. It could be used as a promising diagnostic and prognostic factor, as well as a therapeutic target and tool.

Nrf2 and NF-κB play a key role in inflammation-driven cancers. Conjugation of anti-inflammatory drugs with oleanolic acid oxime (OAO) may enhance their therapeutic potential as a result of downregulation of these pathways. Novel OAO derivatives conjugated with indomethacin (IND) were synthesized, and their effect on the activation and expression of Nrf2 and NF-κB in HepG2 hepatoma cells and THLE-2 immortalized normal hepatocytes was evaluated in relation to cell cycle arrest and apoptosis. Treatment with OAO–IND conjugates reduced the activation of Nrf2 and NF-κB and the expression of their active forms in HepG2 cells, while in normal hepatocytes, the activation of Nrf2 was increased and NF-κB diminished. Compounds 3d, 3-indomethacinoxyiminoolean-12-en-28-oic acid morpholide, and 3c, 3-indomethacinoxyiminoolean-12-en-28-oic acid benzyl ester, were the most efficient. In THLE-2 cells, as opposed to HepG2 cells, the expressions of SOD-1 and NQO1 were significantly enhanced after treatment with these compounds. The COX-2 expression was diminished in both cell lines. OAO–IND derivatives affected the cell cycle arrest at G2/M, leading to increased apoptosis and increased number of resting HepG2 cells. Therefore, the conjugation of IND with OAO derivatives may preserve cancer cells against chemoresistance through the inhibition of the Nrf2-ARE pathway and NF-κB and, at the same time, exert a chemopreventive effect in normal hepatocytes.

Combining NSAIDs with conventional therapeutics was recently explored as a new strategy in cancer therapy. Our earlier studies showed that novel oleanolic acid oximes (OAO) conjugated with aspirin or indomethacin may enhance their anti-cancer potential through modulation of the Nrf2 and NF-κB signaling pathways. This study focused on the synthesis and biological evaluation of four diclofenac (DCL)–OAO derivative conjugates in the context of these pathways’ modification and hepatic cells survival. Treatment with the conjugates 4d, 3-diclofenacoxyiminoolean-12-en-28-oic acid morpholide, and 4c, 3-diclofenacoxyiminoolean-12-en-28-oic acid benzyl ester significantly reduced cell viability in comparison to the DCL alone. In THLE-2, immortalized normal hepatocytes treated with these conjugates resulted in the activation of Nrf2 and increased expression in SOD-1 and NQO1, while the opposite effect was observed in the HepG2 hepatoma cells. In both cell lines, reduced activation of the NF-κB and COX-2 expression was observed. In HepG2 cells, conjugates increased ROS production resulting from a reduced antioxidant defense, induced apoptosis, and inhibited cell proliferation. In addition, the OAO morpholide derivative and its DCL hybrid reduced the tumor volume in mice bearing xenografts. In conclusion, our study demonstrated that conjugating diclofenac with the OAO morpholide and a benzyl ester might enhance its anti-cancer activity in HCC.