Long noncoding RNA PICSAR/miR‐588/EIF6 axis regulates tumorigenesis of hepatocellular carcinoma by activating PI3K/AKT/mTOR signaling pathway

Mechanistic/mammalian target of rapamycin (mTOR), an atypical serine/threonine kinase of the phosphoinositide 3-kinase- (PI3K-) related kinase family, elicits a vital role in diverse cellular processes, including cellular growth, proliferation, survival, protein synthesis, autophagy, and metabolism. In the cardiovascular system, the mTOR signaling pathway integrates both intracellular and extracellular signals and serves as a central regulator of both physiological and pathological processes. MicroRNAs (miRs), a class of short noncoding RNA, are an emerging intricate posttranscriptional modulator of critical gene expression for the development and maintenance of homeostasis across a wide array of tissues, including the cardiovascular system. Over the last decade, numerous studies have revealed an interplay between miRNAs and the mTOR signaling circuit in the different cardiovascular pathophysiology, like myocardial infarction, hypertrophy, fibrosis, heart failure, arrhythmia, inflammation, and atherosclerosis. In this review, we provide a comprehensive state of the current knowledge regarding the mechanisms of interactions between the mTOR signaling pathway and miRs. We have also highlighted the latest advances on mTOR-targeted therapy in clinical trials and the new perspective therapeutic strategies with mTOR-targeting miRs in cardiovascular diseases.

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Oxaliplatin and Gedatolisib (PKI-587) Co-Loaded Hollow Polydopamine Nano-Shells with Simultaneous Upstream and Downstream Action to Re-Sensitize Drugs-Resistant Hepatocellular Carcinoma to Chemotherapy

Journal of Biomedical Nanotechnology ◽

10.1166/jbn.2021.3014 ◽

2021 ◽

Vol 17 (1) ◽

pp. 18-36

Author(s):

Yin-Ci Zhang ◽

Cheng-Guang Wu ◽

A-Min Li ◽

Yong Liang ◽

Dong Ma ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Dna Damage ◽

Drug Resistance ◽

Combination Therapy ◽

Signaling Pathway ◽

Mtor Signaling ◽

Repair Pathway ◽

Mtor Signaling Pathway ◽

Damage Repair ◽

Anti Cancer

Multidrug resistance (MDR) is a key to the ineffectiveness of hepatocellular carcinoma (HCC) chemotherapy. Oxaliplatin (OXA), as one of the first-line chemotherapeutic drugs for HCC, abnormally activates the PI3K/AKT/mTOR signaling pathway and DNA damage repair pathway (NHEJ and HR), causing drug resistance and consequnet compromised efficacy. Herein, we developed a hollow polydopamine nanoparticle (H-PDA)-based nano-delivery system (O/P-HP) that contained OXA and a dual PI3K/mTOR inhibitor PKI-587 with complementary effects for combating drug resistance in cancer chemotherapy. The hollow structure of H-PDA endowed O/P-HP with high loading efficiencies of OXA and PKI-587–up to 49.6% and 7.0%, respectively. In addition, benefiting from the intracellular delivery of H-PDA as well as the highly concentrated drugs therein, O/P-HP inhibited the proliferation of OXA-resistant HR cells, resulting in a cell viability of only 17.63%. These values were significantly superior to those with OXA single-agent treatment and treatment with free OXA in combination with PKI-587. We examined the intrinsic mechanisms of the combination therapy: O/PHP had excellent anti-cancer effects via the simultaneous upstream and downstream action to re-sensitize HR cells to chemotherapy; OXA induced strong apoptosis via the direct platinum lesions on DNA molecules, while PKI-587 normalized the abnormally activated PI3K/AKT/mTOR signaling pathway and DNA damage repair pathway (NHEJ and HR) that could attenuate the effectiveness of OXA, thus resulting in inhibition of cell proliferation, migration and DNA repair enzyme activity and the augment of apoptotic effects. Such combination therapy, with simultaneous upstream and downstream action, may be a strategy for minimizing resistance for anti-cancer treatments.

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