CircRNA: A new class of targets for gastric cancer drug resistance therapy

The emerging role of circular RNAs in cisplatin resistance in ovarian cancer: From molecular mechanism to future potential

Ovarian cancer (OC) is the most common cause of death in female cancers. The prognosis of OC is very poor due to delayed diagnosis and identification of most patients in advanced stages, metastasis, recurrence, and resistance to chemotherapy. As chemotherapy with platinum-based drugs such as cisplatin (DDP) is the main treatment in most OC cases, resistance to DDP is an important obstacle to achieving satisfactory therapeutic efficacy. Consequently, knowing the different molecular mechanisms involved in resistance to DDP is necessary to achieve new therapeutic approaches. According to numerous recent studies, non-coding RNAs (ncRNAs) could regulate proliferation, differentiation, apoptosis, and chemoresistance in many cancers, including OC. Most of these ncRNAs are released by tumor cells into human fluid, allowing them to be used as tools for diagnosis. CircRNAs are ncRNA family members that have a role in the initiation, progression, and chemoresistance regulation of various cancers. In the current study, we investigated the roles of several circRNAs and their signaling pathways on OC progression and also on DDP resistance during chemotherapy.

The function and mechanism of circRNAs in 5-fluorouracil resistance in tumors: Biological mechanisms and future potential

5-Fluorouracil (5-FU) is a well-known chemotherapy drug extensively used in the treatment of breast cancer. It works by inhibiting cancer cell proliferation and inducing cell death through direct incorporation into DNA and RNA via thymidylate synthase (TS). Circular RNAs (circRNAs), a novel family of endogenous non-coding RNAs (ncRNAs) with limited protein-coding potential, contribute to 5-FU resistance. Their identification and targeting are crucial for enhancing chemosensitivity. CircRNAs can regulate tumor formation and invasion by adhering to microRNAs (miRNAs) and interacting with RNA-binding proteins, regulating transcription and translation. MiRNAs can influence enzymes responsible for 5-FU metabolism in cancer cells, affecting their sensitivity or resistance to the drug. In the context of 5-FU resistance, circRNAs can target miRNAs and regulate biological processes such as cell proliferation, cell death, glucose metabolism, hypoxia, epithelial-to-mesenchymal transition (EMT), and drug efflux. This review focuses on the function of circRNAs in 5-FU resistance, discussing the underlying molecular pathways and biological mechanisms. It also presents recent circRNA/miRNA-targeted cancer therapeutic strategies for future clinical application.

CIRCVMA21-RELATED PATHWAY ALLEVIATES LIPOPOLYSACCHARIDE-INDUCED HK-2 CELL INJURY

ABSTRACT

Background : It is reported that circVMA21 has an inhibition effect on sepsis-induced acute kidney injury (AKI). Therefore, the underlying molecular mechanisms of circVMA21 in AKI are worthy of further investigation. Material and Methods : Lipopolysaccharide (LPS) was used to induce HK2 cell injury. CircVMA21, miR-337-3p and ZEB2 expression was tested by qRT-PCR. Cell growth was detected by CCK8 assay, EdU assay, and flow cytometry. Protein levels were examined by western blot. The levels of inflammatory factors and oxidative stress markers were measured to evaluate cell inflammatory response and oxidative stress. RNA relationship as verified by dual-luciferase reporter assay, RIP assay, and RNA pull-down assay. Results : CircVMA21 had decreased expression in AKI patients. Overexpressed circVMA21 alleviated LPS-induced HK2 cell inflammation, apoptosis, and oxidative stress. Moreover, circVMA21 sponged miR-337-3p, and miR-337-3p targeted ZEB2. The inhibitory effect of circVMA21 on LPS-induced HK2 cell injury was reversed by miR-337-3p overexpression, and ZEB2 overexpression abolished the promotion effect of miR-337-3p on LPS-induced HK2 cell injury. Conclusions : CircVMA21 could inhibit LPS-induced HK2 cell injury via miR-337-3p/ZEB2 axis.

Advances in targeted therapy for human epidermal growth factor receptor 2 positive in advanced gastric cancer

Emerging therapeutic methods represented by targeted therapy are effective supplements to traditional first-line chemoradiotherapy resistance. Human epidermal growth factor receptor 2 (HER2) is one of the most important targets in targeted therapy for gastric cancer. Trastuzumab combined with chemotherapy has been used as the first-line treatment for advanced gastric cancer. The safety and efficacy of pertuzumab and margetuximab in the treatment of gastric cancer have been verified. However, monoclonal antibodies, due to their large molecular weight, inability to penetrate the blood-brain barrier, and drug resistance, lead to decreased therapeutic efficacy, so it is necessary to explore the efficacy of other HER2-targeting therapies in gastric cancer. Small-molecule tyrosine kinase inhibitors, such as lapatinib and pyrrotinib, have the advantages of small molecular weight, penetrating the blood-brain barrier and high oral bioavailability, and are expected to become the drugs of choice for perioperative treatment and neoadjuvant therapy of gastric cancer after validation by large-scale clinical trials in the future. Antibo-drug conjugate, such as T-DM1 and T-DXd, can overcome the resistance of monoclonal antibodies despite their different mechanisms of tumor killing, and are a supplement for the treatment of patients who have failed the treatment of monoclonal antibodies such as trastuzumab. Therefore, after more detailed stratification of gastric cancer patients, various gastric cancer drugs targeting HER2 are expected to play a more significant role.

Exosomal circ_0000735 contributes to non-small lung cancer malignant progression

Circular RNA is an important regulator for non-small cell lung cancer (NSCLC). Circ_0000735 has been found to be significantly overexpressed in NSCLC tissues. Therefore, its role and mechanism in NSCLC progression need to be further explored. The expression levels of circ_0000735, miR-345-5p and A disintegrin and metalloprotease 19 (ADAM19) were determined using quantitative real-time PCR. EdU staining, wound healing and transwell assays were utilized to detect cell proliferation and metastasis. The protein levels of metastasis markers, exosome markers and ADAM19 were determined using western blot. Animal experiments were performed to confirm the role of circ_0000735 in NSCLC tumorigenesis. The exosomes from cells and serum were identified using transmission electron microscopy and nanoparticle tracking analysis. We found that circ_0000735 was upregulated in NSCLC, and its knockdown repressed NSCLC cell proliferation and metastasis. In terms of mechanism, circ_0000735 targeted miR-345-5p to regulate ADAM19. MiR-345-5p inhibitor reversed the suppressive effect of circ_0000735 knockdown on NSCLC progression, and ADAM19 overexpression abolished the inhibition effect of miR-345-5p on NSCLC progression. Also, animal experiments showed that silencing of circ_0000735 reduced NSCLC tumorigenesis. In addition, exosomes mediated the intercellular transmission of circ_0000735, and serum exosomal circ_0000735 might be an important indicator for the diagnosis of NSCLC. In conclusion, circ_0000735 facilitated NSCLC progression via miR-345-5p/ADAM19 pathway, and serum exosomal circ_0000735 might be a potential biomarker for NSCLC diagnosis.

Exosomal circRNAs in gastrointestinal cancer: Role in occurrence, development, diagnosis and clinical application (Review)

Gastrointestinal cancer is frequently detected at an advanced stage and has an undesirable prognosis due to the absence of efficient and precise biomarkers and therapeutic targets. Exosomes are small, living‑cell‑derived vesicles that serve a critical role in facilitating intercellular communication by transporting molecules from donor cells to receiver cells. circular RNAs (circRNAs) are mis‑expressed in a variety of diseases, including gastrointestinal cancer, and are promising as diagnostic biomarkers and tumor therapeutic targets for gastrointestinal cancer. The main features of exosomes and circRNAs are discussed in the present review, along with research on the biological function of exosomal circRNAs in the development and progression of gastrointestinal cancer. It also assesses the advantages and disadvantages of implementing these findings in clinical applications.

MicroRNA-183 cluster: a promising biomarker and therapeutic target in gastrointestinal malignancies

Small non-coding RNAs (microRNA, miR), powerful epigenetic regulators, were found involved in the regulation of most biological functions via post-translational inhibition of protein expression. Increased expression of pro-oncogenic miRs (known as miR cancer biomarkers) and inhibition of pro-apoptotic miR expression have been demonstrated in different tumors. The recently identified miR-183 was found implicated in gastrointestinal tumor metabolism regulation. Elevated miR-183 expression and cancer-promoting effects were reported in esophageal and colorectal cancers, which was partially contradicted by controversial data observed in gastric cancers. Anti-cancer effect of miR-183 in gastric cancer cells was associated with the Bim-1 and Ezrin genes regulation. Many studies indicated that miR-183 can inhibit tumor suppressor genes in most cell lines, promoting tumor cell proliferation and migration. Increased miR-183 level results in the downregulation of FOXO1, PDCD4, and other tumor suppressor genes in gastrointestinal tumor cells. MiR-183 also influences the signaling of PI3K/AKT/mTOR, Wnt/β-catenin, and Bcl-2/p53 signaling pathways. Mir-183 inhibits apoptosis and autophagy, and promotes epithelial-to-mesenchymal transition, cancer cell proliferation, and migration. Accordingly, gastrointestinal cancer occurrence, development of chemoradiotherapy resistance, recurrence/metastasis, and prognosis were associated with miR-183 expression. The current study assessed reported miR-183 functions and signaling, providing new insights for the diagnosis and treatment of gastrointestinal malignancies.

Mechanism of cisplatin resistance in gastric cancer and associated microRNAs

Gastric cancer (GC) is a common malignant tumor with high morbidity and mortality rates that seriously affects human health worldwide. Although surgery is currently the preferred clinical treatment for GC, chemotherapy remains the first choice for perioperative treatment, adjuvant therapy, and palliative care for patients with advanced GC. Cisplatin (DDP) is an antineoplastic agent that has been used clinically for decades, and it is the first-line chemotherapy for many solid tumors. However, the therapeutic efficacy of DDP is often limited by resistance and the complexity of its resistance mechanisms, which involve multiple proteins and signaling pathways. It is well documented that a variety of microRNAs (miRNAs) differentially expressed in DDP-resistant GC cells play important roles in regulating or reversing DDP resistance via various pathways. In this review, we first provide an introduction to the cytotoxicity and major resistance mechanisms of DDP in GC and then discuss the role and mechanism of miRNAs in regulating the DDP resistance process in GC cells. This work demonstrates the potential of relevant miRNAs to become diagnostic and prognostic biomarkers for gastric cancer and targets of action to enhance chemosensitivity and provides directions for future research.

Hsa_circ_0000585 promotes chemoresistance to cis-platin in epithelial cells of ovarian cancer by modulating autophagy

BACKGROUND

Chemoresistance, i.e., resistance to cisplatin (DDP), has been a major obstacle to ovarian cancer treatment. It has been found that circular RNAs (circRNAs) play vital roles in the tumorigenesis various cancers by regulating autophagy, while few studies focusing on cisplatin-resistance ovarian cancer (CROC).

METHODS

The expressions of the circRNAs were detected by qRT-PCR. Short hairpin RNA targeting circRNA was used to explore the biological functions of the circRNA. Cell viability, autophagic flux, immunofluorescence, and xenograft tumors experiments were performed to further illustrate the underlying mechanisms.

RESULTS

Hsa_circ_0000585 was increased in cisplatin-resistant SKOV3/DDP cells. Stably knocking down hsa_circRNA_0000585 expression in SKOV3/DDP cells was established by RNA interference. We found that downregulation of hsa_circ_0000585 significantly enhanced the sensitivity of DDP/SkOV3 cells to DDP. In vivo study, hsa_circRNA_0000585 knockdown significantly decreased tumor volume in nude mice. Under the measurements of western blot and cellular immunofluorescence, hsa_circ_0000585 knockdown significantly inhibited the expression of Beclin1 and P62, indicating the autophagic flux was inhibited. Administrations with autophagic inhibitor "Chloroquine (CQ)" and autophagy activator "QX77" further confirmed that hsa_circ_0000585 knockdown resulted in autophagy inhibition.

CONCLUSIONS

Overall, this study provided a new insight into the role of circRNAs in the mechanism of DDP-resistance in ovarian cancer. Hsa_circRNA_0000585 may be promising therapeutic targets for the enhancement of the sensitivity of ovarian cancer cells to cisplatin-mediated chemotherapy.

Expression And Prognostic Role of PRDX1 In Gastrointestinal Cancers

Esophageal, gastric, liver, and colorectal cancers represent four prevalent gastrointestinal cancers that pose substantial threats to global health due to their high morbidity and mortality rates. Peroxiredoxin 1 (PRDX1), a significant component of the PRDXs family, primarily functions to counteract the peroxides produced by metabolic activities in the body, thereby maintaining the dynamic equilibrium of peroxides in vivo. Intriguingly, PRDX1 expression correlates strongly with cancer's onset, progression, and prognosis. This study mainly applied bioinformatics methods to analyze PRDX1's expression, diagnosis, and prognosis in gastrointestinal cancers and to summarize current research advancements. Evidence from the bioinformatics database suggested that the high expression of PRDX1 was a prominent characteristic of these four gastrointestinal cancers, with this observation reaching statistical significance. The high expression of PRDX1 in gastrointestinal cancer cells also confirms this result. Notably, the primary alteration in PRDX1 within these cancers is the presence of genetic mutations. PRDX1 demonstrated the highest diagnostic efficacy for colorectal cancer. Nevertheless, elevated PRDX1 levels only significantly diminished the survival time of liver cancer patients, exerting no statistically significant impact on the survival duration of patients afflicted by the other three types of gastrointestinal cancers. Recent research has indicated variability in PRDX1 expression across different cancer types, with high expression being predominantly observed in these four gastrointestinal cancers and, in most instances, unfavorable prognosis. These findings broadly align with the results derived from bioinformatics. This research underscores the high expression of PRDX1 in gastrointestinal cancers, its relevance to the diagnosis and prognosis monitoring of these cancers, and its potential to guide clinical treatment for these cancers.

Modulating multidrug resistance to drug-based antitumor therapies through NF-κB signaling pathway: mechanisms and perspectives

INTRODUCTION

Despite the advances made in cancer treatment in the past decades, therapeutic efficacy is still quite challenging, partially due to the emergence of multidrug resistance (MDR). It is crucial to decipher the underlying mechanisms of resistance in order to develop new therapeutic strategies for cancer patients. Previous studies have shown that activation of nuclear factor-κB (NF-κB) plays key roles in various cellular processes including proliferation, anti-apoptosis, metastasis, invasion, and chemoresistance.

AREAS COVERED

In this review, we conduct an integrated analysis of the evidence suggesting the vital roles of the NF-κB signaling pathway in MDR during chemotherapy, immunotherapy, endocrine, and targeted therapy. A literature search was performed on NF-κB and drug resistance in PubMed up to February 2023.

EXPERT OPINION

This review summarizes that the NF-κB signaling pathway exhibits a crucial role in enhancing drug resistance in chemotherapy, immunotherapy, endocrine, and targeted therapy. The application of combination therapy with existing antineoplastic drugs and a safe NF-κB inhibitor could become a promising strategy in cancer treatment. A better understanding of the pathway and mechanisms of drug resistance may help exploit safer and more effective NF-κB-targeting agents for clinical use in the future.