Role of PARP1-mediated autophagy in EGFR-TKI resistance in non-small cell lung cancer

PARP1 promotes EGFR-TKI drug-resistance via PI3K/AKT pathway in non-small-cell lung cancer

PURPOSE

Tyrosine kinase inhibitor (TKI) resistance is the main type of drug resistance in lung cancer patients with epidermal growth factor receptor (EGFR) mutations, but its underlying mechanism remains unclear. The purpose of this work was to investigate the mechanism by which PARP1 regulates EGFR-TKI resistance to identify potential targets for combating drug resistance.

METHODS

The GEO databases, TCGA databases, western blot and qPCR studies were used to investigate the expression of PARP1 in lung cancer cells and tissues and its correlation with the prognosis of lung cancer. The expression of PARP1 in lung cancer TKI resistant cell PC9-ER and TKI sensitive cell PC9 was analyzed by qPCR and western blot. After knocking down of PARP1, CCK-8 assays, colony formation, flow cytometry were used to investigate its impact on erlotinib sensitivity, cell survival, cell cycle, and apoptosis. RNA-seq was used to investigate the mechanism by which PARP1 participates in EGFR-TKI resistance, and the results were validated in vitro and in vivo studies.

RESULTS

PARP1 was highly expressed in both lung cancer tissues and cells. Subsequently, increased PARP1 expression was observed in PC9-ER compared with its parental cell line. Knockdown of PARP1 increased erlotinib sensitivity, promoted cell apoptosis, and suppressed cell growth. RNA-seq and previous studies have shown that the PI3K/AKT/mTOR/P70S6K pathway is involved in PARP1-mediated TKI resistance, and these results were confirmed by Western blot in vitro and in vivo.

CONCLUSION

PARP1 may serve as a potential therapeutic target for reversing EGFR-TKI resistance in NSCLC via the PI3K/AKT/mTOR/P70S6K pathway.

A molecularly engineered lectin destroys EGFR and inhibits the growth of non-small cell lung cancer

Survival rates for non-small cell lung cancer (NSCLC) remain low despite the advent of novel therapeutics. Tyrosine kinase inhibitors (TKIs) targeting mutant epidermal growth factor receptor (EGFR) in NSCLC have significantly improved mortality but are plagued with challenges--they can only be used in the small fraction of patients who have susceptible driver mutations, and resistance inevitably develops. Aberrant glycosylation on the surface of cancer cells is an attractive therapeutic target as these abnormal glycosylation patterns are typically specific to cancer cells and are not present on healthy cells. H84T BanLec (H84T), a lectin previously engineered by our group to separate its antiviral activity from its mitogenicity, exhibits precision binding of high mannose, an abnormal glycan present on the surface of many cancer cells, including NSCLC. Here, we show that H84T binds to and inhibits the growth of diverse NSCLC cell lines by inducing lysosomal degradation of EGFR and leading to cancer cell death through autophagy. This is a mechanism distinct from EGFR TKIs and is independent of EGFR mutation status; H84T inhibited proliferation of both cell lines expressing wild type EGFR and those expressing mutant EGFR that is resistant to all TKIs. Further, H84T binds strongly to multiple and diverse clinical samples of both pulmonary adenocarcinoma and squamous cell carcinoma. H84T is thus a promising potential therapeutic in NSCLC, with the ability to circumvent the challenges currently faced by EGFR TKIs.

UHRF2 promotes the malignancy of hepatocellular carcinoma by PARP1 mediated autophagy

Autophagy have critical implications in the proliferation and metastasis of HCC. In the current study, we aimed to explore the underlying mechanisms of UHRF2 regulates HCC cell autophagy and HCC progression. We initially determined the relationship between UHRF2 and HCC autophagy, oncogenicity and patient survival through GSEA database and TCGA database. We mainly investigated the effect of UHRF2 on HCC development and autophagy through western blot, electron microscopy, and immunofluorescence. Functionally, UHRF2 was positively involved in the autophagy activation. Overexpression of UHRF2 reduced apoptosis in HCC cells, and promote the malignancy phenotype of HCC both in vitro and in vivo. Mechanistically, PRDX1 bound to UHRF2 and upregulated its protein expression to facilitate the biological function of UHRF2 in HCC. Meanwhile, UHRF2 bound to autophagy-related protein PARP1 and upregulated PARP1 protein level. The results showed that UHRF2 promoted autophagy and contributed to the malignant phenotype of hepatocellular carcinoma by regulating PARP1 levels. In summary, a novel interaction between PRDX1, UHRF2, and PARP1 was revealed, suggesting that UHRF2 could inspire a potential biomarker and potential therapeutic target for HCC.

Eukaryotic initiation factor 5A2 mediates hypoxia-induced autophagy and cisplatin resistance

Hypoxia-induced cisplatin resistance is a major challenge during non-small cell lung cancer (NSCLC) treatment. Based on previous studies, we further explored the effect of eukaryotic initiation factor 5A2 (eIF5A2) in hypoxia-induced cisplatin resistance. In this study, we found that autophagy and cisplatin resistance were increased under hypoxic conditions in three different NSCLC cell lines. Compared with that under normoxic conditions, dramatic upregulation of eIF5A2 and hypoxia inducible factor 1 subunit alpha (HIF-1α) levels were detected under hypoxia exposure. Small interfering RNA silencing of HIF-1α resulted in decreased expression of eIF5A2, indicating that eIF5A2 acts downstream of HIF-1α. In addition, the expression of eIF5A2 was significantly higher in NSCLC tumors compared with that in normal tissues. RNA silencing-mediated downregulation of eIF5A2 decreased hypoxia-induced autophagy, thereby reducing hypoxia-induced cisplatin resistance in NSCLC cells. The roles of eIF5A2 in cisplatin resistance were further validated in vivo. Combined treatment using eIF5A2-targeted downregulation together with cisplatin significantly inhibited tumor growth compared with cisplatin alone in the subcutaneous mouse model. In conclusions, eIF5A2 overexpression is involved in hypoxia-induced autophagy during cisplatin resistance. We suggest that a combination of eIF5A2 targeted therapy and cisplatin chemotherapy is probably an effective strategy to reverse hypoxia-induced cisplatin resistance and inhibit NSCLC development.

[DNA Damage Repair System and Antineoplastic Agents in Lung Cancer]

DNA damage repair (DDR) system plays an important role in maintaining of genomic stability. Accumulation of DNA lesions or deficiency of DDR system could drive tumorigenesis as well as promote tumor progression; meanwhile, they could also provide therapeutic opportunities and targets. Of all the antineoplastic agents of lung cancers, many of them targeted or were associated with DNA damage and repair pathways, such as chemotherapies and antibody-drug conjugates which were designed directly causing DNA damages, targeted drugs inhibiting DNA repair pathways, and immune-checkpoint inhibitors. In this review, we described the role of DNA damage and repair pathways in antitumor activity of the above agents, as well as summarized the application and clinical investigations of these antineoplastic agents in lung cancers, in order to provide more information for exploring precision and effective strategies for the treatment of lung cancer based on the mechanism of DNA damage and repair.
.

Impact of clinical and molecular features on efficacy and outcome of patients with non-small cell lung cancer receiving second-line osimertinib

Background

Although with the impressive efficacy, several patients showed intrinsic resistance or an unsatisfactory response to Osimertinib. We aim to explore the impact of clinical and molecular features on efficacy and outcome of patients with EGFR T790M-mutation non-small cell lung cancer (NSCLC) receiving second-line Osimertinib.

Methods

Patients with EGFR T790M-mutant NSCLC who had acquired resistance to the first-generation EGFR TKI and then received Osimertinib as second-line treatment were included. Patients’ demographic and clinical information, as well as molecular data were extracted from electronic medical records. The impact of clinical and molecular features on treatment response and patients’ outcome were assessed.

Results

Among the 99 patients, 60 patients were tissue/pleural effusion T790M positive and 69 patients were plasma positive with a median PFS of 12.1 m and 9.9 m (P = 0.25), respectively. In addition, median PFS were similar between patients of plasma T790M + and patients of plasma T790M- (P = 0.94). The Pearson correlation test showed no significant relationship between plasma T790M abundance and PFS (r = 0.074, P = 0.546). In subgroup analyses, PFS was significantly improved in elder patients (P = 0.009) and patients with longer PFS to the first-generation EGFR TKI (P = 0.0008), while smokers tended to have worse PFS compared with non-smokers (P = 0.064). PARP1 mutant-type patients had a worse PFS compared with wild-type group (P = 0.0003). Patients with MYC amplification also had a worse PFS than MYC wild-type patients (P = 0.016). A significant PFS shrinkage was observed in TMB-High group as 6.77 m, compared with 19.10 m in TMB-Low group. The multivariate Cox analysis revealed that years ≥ 65 was an independent positive feature for PFS, while PARP1 mutation and TMB-H were negative features for PFS.

Conclusion

In conclusion, our findings in this study demonstrated that clinical and molecular features can be served as predictive biomarkers to stratify patients with EGFR T790M-mutant NSCLC receiving second-line Osimertinib.

Supplementary information

The online version contains supplementary material available at 10.1186/s12885-022-09683-1.

Autophagy-Related Three-Gene Prognostic Signature for Predicting Survival in Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive malignant tumors in China, and its prognosis remains poor. Autophagy is an evolutionarily conserved catabolic process involved in the occurrence and development of ESCC. In this study, we described the expression profile of autophagy-related genes (ARGs) in ESCC and developed a prognostic prediction model for ESCC patients based on the expression pattern of ARGs. We used four ESCC cohorts, GSE53624 (119 samples) set as the discovery cohort, The Cancer Genome Atlas (TCGA) ESCC set (95 samples) as the validation cohort, 155 ESCC cohort, and Oncomine cohort were used to screen and verify differentially expressed ARGs. We identified 34 differentially expressed genes out of 222 ARGs. In the discovery cohort, we divided ESCC patients into three groups that showed significant differences in prognosis. Then, we analyzed the prognosis of 34 differentially expressed ARGs. Three genes [poly (ADP-ribose) polymerase 1 (PARP1), integrin alpha-6 (ITGA6), and Fas-associated death domain (FADD)] were ultimately obtained through random forest feature selection and were constructed as an ARG-related prognostic model. This model was further validated in TCGA ESCC set. Cox regression analysis confirmed that the three-gene signature was an independent prognostic factor for ESCC patients. This signature effectively stratified patients in both discovery and validation cohorts by overall survival (P = 5.162E-8 and P = 0.052, respectively). We also constructed a clinical nomogram with a concordance index of 0.713 to predict the survival possibility of ESCC patients by integrating clinical characteristics and the ARG signature. The calibration curves substantiated fine concordance between nomogram prediction and actual observation. In conclusion, we constructed a new ARG-related prognostic model, which shows the potential to improve the ability of individualized prognosis prediction in ESCC.

PFKFB3 Inhibition Impairs Erlotinib-Induced Autophagy in NSCLCs

Tyrosine kinase inhibitors (TKIs) targeting the kinase domain of the epidermal growth factor receptor (EGFR), such as erlotinib, have dramatically improved clinical outcomes of patients with EGFR-driven non-small cell lung carcinomas (NSCLCs). However, intrinsic or acquired resistance remains a clinical barrier to the success of FDA-approved EGFR TKIs. Multiple mechanisms of resistance have been identified, including the activation of prosurvival autophagy. We have previously shown that the expression and activity of PFKFB3—a known driver of glycolysis—is associated with resistance to erlotinib and that PFKFB3 inhibition improves the response of NSCLC cells to erlotinib. This study focuses on investigating the role of PFKFB3 in regulating erlotinib-driven autophagy to escape resistance to erlotinib. We evaluated the consequence of pharmacological inhibition of PFKFB3 on erlotinib-driven autophagy in NSCLC cells with different mutation statuses. Here, we identify PFKFB3 as a mediator of erlotinib-induced autophagy in NSCLCs. We demonstrate that PFKFB3 inhibition sensitizes NCSLCs to erlotinib via impairing autophagy flux. In summary, our studies uncovered a novel crosstalk between PFKFB3 and EGFR that regulates erlotinib-induced autophagy, thus contributing to erlotinib sensitivity in NSCLCs.