Human RECQL5 promotes metastasis and resistance to cisplatin in non-small cell lung cancer

Hsa_circ_0096157 silencing suppresses autophagy and reduces cisplatin resistance in non-small cell lung cancer by weakening the Nrf2/ARE signaling pathway

BACKGROUND

Non-small cell lung cancer (NSCLC) is the leading cause of cancer morbidity and mortality worldwide, and new diagnostic markers are urgently needed. We aimed to investigate the mechanism by which hsa_circ_0096157 regulates autophagy and cisplatin (DDP) resistance in NSCLC.

METHODS

A549 cells were treated with DDP (0 μg/mL or 3 μg/mL). Then, the autophagy activator rapamycin (200 nm) was applied to the A549/DDP cells. Moreover, hsa_circ_0096157 and Nrf2 were knocked down, and Nrf2 was overexpressed in A549/DDP cells. The expression of Hsa_circ_0096157, the Nrf2/ARE pathway-related factors Nrf2, HO-1, and NQO1, and the autophagy-related factors LC3, Beclin-1, and p62 was evaluated by qRT‒PCR or western blotting. Autophagosomes were detected through TEM. An MTS assay was utilized to measure cell proliferation. The associated miRNA levels were also tested by qRT‒PCR.

RESULTS

DDP (3 μg/mL) promoted hsa_circ_0096157, LC3 II/I, and Beclin-1 expression and decreased p62 expression. Knocking down hsa_circ_0096157 resulted in the downregulation of LC3 II/I and Beclin-1 expression, upregulation of p62 expression, and decreased proliferation. Rapamycin reversed the effect of interfering with hsa_circ_0096157. Keap1 expression was lower, and Nrf2, HO-1, and NQO1 expression was greater in the A549/DDP group than in the A549 group. HO-1 expression was repressed after Nrf2 interference. In addition, activation of the Nrf2/ARE pathway promoted autophagy in A549/DDP cells. Moreover, hsa_circ_0096157 activated the Nrf2/ARE pathway. The silencing of hsa_circ_0096157 reduced Nrf2 expression by releasing miR-142-5p or miR-548n. Finally, we found that hsa_circ_0096157 promoted A549/DDP cell autophagy by activating the Nrf2/ARE pathway.

CONCLUSION

Knockdown of hsa_circ_0096157 inhibits autophagy and DDP resistance in NSCLC cells by downregulating the Nrf2/ARE signaling pathway.

Fascin actin-bundling protein 1 regulates non-small cell lung cancer progression by influencing the transcription and splicing of tumorigenesis-related genes

Background

High mortality rates are prevalent among patients with non-small-cell lung cancer (NSCLC), and effective therapeutic targets are key prognostic factors. Fascin actin-bundling protein 1 (FSCN1) promotes NSCLC; however, its role as an RNA-binding protein in NSCLC remains unexplored. Therefore, we aimed to explore FSCN1 expression and function in A549 cells.

Method

We screened for alternative-splicing events and differentially expressed genes (DEGs) after FSCN1 silence via RNA-sequencing (RNA-seq). FSCN1 immunoprecipitation followed by RNA-seq were used to identify target genes whose mRNA expression and pre-mRNA alternative-splicing levels might be influenced by FSCN1.

Results

Silencing FSCN1 in A549 cells affected malignant phenotypes; it inhibited proliferation, migration, and invasion, and promoted apoptosis. RNA-seq analysis revealed 2,851 DEGs and 3,057 alternatively spliced genes. Gene ontology-based functional enrichment analysis showed that downregulated DEGs and alternatively splicing genes were enriched for the cell-cycle. FSCN1 promoted the alternative splicing of cell-cycle-related mRNAs involved in tumorigenesis (i.e., BCCIP, DLGAP5, PRC1, RECQL5, WTAP, and SGO1). Combined analysis of FSCN1 RNA-binding targets and RNA-seq data suggested that FSCN1 might affect ACTG1, KRT7, and PDE3A expression by modulating the pre-mRNA alternative-splicing levels of NME4, NCOR2, and EEF1D, that were bound to long non-coding RNA transcripts (RNASNHG20, NEAT1, NSD2, and FTH1), which were highly abundant. Overall, extensive transcriptome analysis of gene alternative splicing and expression levels was performed in cells transfected with FSCN1 short-interfering RNA. Our data provide global insights into the regulatory mechanisms associated with the roles of FSCN1 and its target genes in lung cancer.

Gene polymorphisms associated with sudden decreases in heart rate during extensive peritoneal lavage with distilled water after gastrectomy

BACKGROUND

Our previous study found that the telomerase-associated protein 1 (TEP1, rs938886 and rs1713449) and homo sapiens RecQ like helicase 5 (RECQL5, rs820196) single nucleotide polymorphisms (SNPs) were associated with changes in heart rate (HR) ≥ 30% during peritoneal lavage with distilled water after gastrectomy. This study established a single tube method for detecting these three SNPs using two-dimensional (2D) polymerase chain reaction (PCR), and investigated whether SNP-SNP and SNP-environment interactions increase the risk of high HR variability (HRV).

AIM

To investigate whether genotypes, genetic patterns, SNP-SNP and SNP-environment interactions were associated with HRV.

METHODS

2D PCR was used to establish a single-tube method to detect TEP1 rs938886 and rs1713449 and RECQL5 rs820196, and the results were compared with those of sanger sequencing. After adjusting for confounders such as age, sex, smoking, hypertension, and thyroid dysfunction, a nonconditional logistic regression model was used to assess the associations between the genotypes and the genetic patterns (codominant, dominant, overdominant, recessive, and additive) of the three SNPs and a risk ≥ 15% or ≥ 30% of a sudden drop in HR during postoperative peritoneal lavage in patients with gastric cancer. Gene-gene and gene-environment interactions were analyzed using generalized multifactor dimensionality reduction.

RESULTS

The coincidence rate between the 2D PCR and sequencing was 100%. When the HRV cutoff value was 15%, the patients with the RECQL5 (rs820196) TC genotype had a higher risk of high HRV than those who had the TT genotype (odds ratio = 1.97; 95%CI: 1.05-3.70; P = 0.045). Under the codominant and overdominant models, the TC genotype of RECQL5 (rs820196) was associated with a higher risk of HR decrease relative to the TT and TT + CC genotypes (P = 0.031 and 0.016, respectively). When the HRV cutoff value was 30%, patients carrying the GC-TC genotypes of rs938886 and rs820196 showed a higher HRV risk when compared with the GG-TT genotype carriers (P = 0.01). In the three-factor model of rs938886, rs820196, and rs1713449, patients carrying the GC-TC-CT genotype had a higher risk of HRV compared with the wild-type GG-TT-CC carriers (P = 0.01). For rs820196, nonsmokers with the TC genotype had a higher HRV risk compared with nonsmokers carrying the TT genotype (P = 0.04). When the HRV cutoff value was 15%, patients carrying the TT-TT and the TC-CT genotypes of rs820196 and rs1713449 showed a higher HRV risk when compared with TT-CC genotype carriers (P = 0.04 and 0.01, respectively). Patients carrying the GC-CT-TC genotypes of rs938886, rs1713449, and rs820196 showed a higher HRV risk compared with GG-CC-TT genotype carriers (P = 0.02). When the HRV cutoff value was 15%, the best-fitting models for the interactions between the SNPs and the environment were the rs820196-smoking (P = 0.022) and rs820196-hypertension (P = 0.043) models. Consistent with the results of the previous grouping, for rs820196, the TC genotype nonsmokers had a higher HRV risk compared with nonsmokers carrying the TT genotype (P = 0.01).

CONCLUSION

The polymorphism of the RECQL5 and TEP1 genes were associated with HRV during peritoneal lavage with distilled water after gastrectomy.

Functional inhibition of RECQL5 helicase elicits non-homologous end joining response and sensitivity of breast cancers to PARP inhibitor

Poly (ADPRibose) Polymerase inhibitor (PARPi) are clinically approved for the treatment of BRCA-mutated hereditary breast and ovarian cancers with homologous recombination (HR) deficiency, based on synthetic lethality concept. However, ∼90% of breast cancers are BRCA-wild type; they repair PARPi mediated damage through HR, leading to intrinsic de novo resistance. Hence, there is an unmet need of exploring novel targets in HR-proficient aggressive breast cancers for PARPi treatment. RECQL5 physically interacts and disrupts RAD51 from pre-synaptic filaments, aiding HR resolution, replication fork protection and preventing illegitimate recombination. In the current investigation, we show that targeted inhibition of HR by stabilization of RAD51-RECQL5 complex by a pharmacological inhibitor of RECQL5 (4a; 1,3,4-oxadiazole derivative) in the presence of PARPi [talazoparib (BMN673)] leads to abolition of functional HR with uncontrolled activation of NHEJ repair. This was assessed by GFP based NHEJ reporter assay, KU80 recruitment and in vitro NHEJ based plasmid ligation assay. Concomitant treatment with talazoparib and 4a generates copious amounts of replication stress, prolonged cell cycle arrest, extensive double strand breaks (DSBs) and mitotic catastrophe, leading to sensitization of HR-proficient breast cancers. Suppression of NHEJ activity abolishes 4a-mediated sensitization of breast cancers to PARPi treatment. Imperatively, 4a was ineffective against normal mammary epithelial cells, which expresses low RECQL5 vis-à-vis breast cancer cells. Moreover, functional inhibition of RECQL5 suppresses metastatic potential of breast cancer cells in response to PARPi. Together, we identified RECQL5 as a novel pharmacological target for expanding PARPi based treatment horizon for HR-proficient cancers.

Case report: A novel mutation of RecQ-like helicase 5 in a Chinese family with early myocardial infarction, coronary artery disease, and stroke hemiplegia

Background: Myocardial infarction (MI) is a type of severe coronary artery disease (CAD) that can lead to heart failure and sudden cardiac death. The prevalence of heart failure globally is estimated at 1%-2%, of which ∼60% of cases are the consequence of MI as the primary cause. At present, several disease-causing genes have been identified that may be responsible for MI, such as autophagy-related 16-like 1 (ATG16L1) and RecQ-like helicase 5 (RECQL5). Methods: In this study, we enrolled a Chinese family with MI, CAD, and stroke hemiplegia. Whole-exome sequencing was applied to analyze the genetic lesion of the proband. Sanger sequencing was used to validate the candidate mutation in five family members and 200 local control cohorts. Results: After data filtering, we detected a novel mutation (NM_004259: c.1247T>C/p.I416T) of RECQL5 in the proband. Sanger sequencing further validated that the novel mutation was existent in the affected individuals, including the proband's younger sister and her mother, and absent in the other healthy family members and 200 local control cohorts. Furthermore, bioinformatics analysis confirmed that the novel mutation, located in a highly evolutionarily conserved site, was predicted to be deleterious and may change the hydrophobic surface area and aliphatic index of RECQL5. Conclusion: Here, we report the second mutation (NM_004259: c.1247T>C/p.I416T) of RECQL5 underlying MI and CAD by whole-exome sequencing. Our study expanded the spectrum of RECQL5 mutations and contributed to genetic diagnosis and counseling of MI and CAD.

RecQ Helicase Somatic Alterations in Cancer

Named the “caretakers” of the genome, RecQ helicases function in several pathways to maintain genomic stability and repair DNA. This highly conserved family of enzymes consist of five different proteins in humans: RECQL1, BLM, WRN, RECQL4, and RECQL5. Biallelic germline mutations in BLM, WRN, and RECQL4 have been linked to rare cancer-predisposing syndromes. Emerging research has also implicated somatic alterations in RecQ helicases in a variety of cancers, including hematological malignancies, breast cancer, osteosarcoma, amongst others. These alterations in RecQ helicases, particularly overexpression, may lead to increased resistance of cancer cells to conventional chemotherapy. Downregulation of these proteins may allow for increased sensitivity to chemotherapy, and, therefore, may be important therapeutic targets. Here we provide a comprehensive review of our current understanding of the role of RecQ DNA helicases in cancer and discuss the potential therapeutic opportunities in targeting these helicases.

Regulation of apoptosis, autophagy and ferroptosis by non‑coding RNAs in metastatic non‑small cell lung cancer (Review)

Non-small cell lung cancer (NSCLC), a common type of cancer worldwide, is normally associated with a poor prognosis. It is difficult to treat successfully as it often metastasizes into brain or bone. Methods to facilitate the induction of effective programmed cell death (PCD) in NSCLC cells to reverse drug resistance, or to inhibit the invasion and migration of NSCLC cells, are currently under investigation. The present study summarized the regulatory functions of PCD, including apoptosis, autophagy and ferroptosis, in the context of NSCLC metastasis. It further summarized how regulatory agents, including long non-coding RNAs, circular RNAs and microRNAs, regulate PCD during the metastasis of NSCLC and characterized new potential diagnostic biomarkers of NSCLC metastasis.

Human RecQL4 as a Novel Molecular Target for Cancer Therapy

Human RecQ helicases play diverse roles in the maintenance of genomic stability. Inactivating mutations in 3 of the 5 human RecQ helicases are responsible for the pathogenesis of Werner syndrome (WS), Bloom syndrome (BS), Rothmund-Thomson syndrome (RTS), RAPADILINO, and Baller-Gerold syndrome (BGS). WS, BS, and RTS patients are at increased risk for developing many age-associated diseases including cancer. Mutations in RecQL1 and RecQL5 have not yet been associated with any human diseases so far. In terms of disease outcome, RecQL4 deserves special attention because mutations in RecQL4 result in 3 autosomal recessive syndromes (RTS type II, RAPADILINO, and BGS). RecQL4, like other human RecQ helicases, has been demonstrated to play a crucial role in the maintenance of genomic stability through participation in diverse DNA metabolic activities. Increased incidence of osteosarcoma in RecQL4-mutated RTS patients and elevated expression of RecQL4 in sporadic cancers including osteosarcoma suggest that loss or gain of RecQL4 expression is linked with cancer susceptibility. In this review, current and future perspectives are discussed on the potential use of RecQL4 as a novel cancer therapeutic target.