BIM deletion polymorphism predicts poor response to EGFR-TKIs in nonsmall cell lung cancer: An updated meta-analysis

Coexpression of TP53, BIM, and PTEN Enhances the Therapeutic Efficacy of Non-Small-Cell Lung Cancer

For non-small-cell lung cancer (NSCLC), the ubiquitous occurrence of concurrent multiple genomic alterations poses challenges to single-gene therapy. To increase therapeutic efficacy, we used the branch-PCR method to develop a multigene nanovector, NP-TP53-BIM-PTEN, that carried three therapeutic gene expression cassettes for coexpression. NP-TP53-BIM-PTEN exhibited a uniform size of 104.8 ± 24.2 nm and high serum stability. In cell transfection tests, NP-TP53-BIM-PTEN could coexpress TP53, BIM, and PTEN in NCI-H1299 cells and induce cell apoptosis with a ratio of up to 94.9%. Furthermore, NP-TP53-BIM-PTEN also inhibited cell proliferation with a ratio of up to 42%. In a mouse model bearing an NCI-H1299 xenograft tumor, NP-TP53-BIM-PTEN exhibited a stronger inhibitory effect on the NCI-H1299 xenograft tumor than the other test vectors without any detectable side effects. These results exhibited the potential of NP-TP53-BIM-PTEN as an effective and safe multigene nanovector to enhance NSCLC therapy efficacy, which will provide a framework for genome therapy with multigene combinations.

Genomic Landscape of Primary Resistance to Osimertinib Among Hispanic Patients with EGFR-Mutant Non-Small Cell Lung Cancer (NSCLC): Results of an Observational Longitudinal Cohort Study

BACKGROUND

Epidermal growth factor receptor (EGFR) mutations (EGFRm) represent one of the most common genomic alterations identified among patients with non-small cell lung cancer (NSCLC). Several targeted agents for patients with EGFRm have been proven safe and effective, including the third-generation tyrosine kinase inhibitor (TKI) osimertinib. Nonetheless, some patients will present with or develop EGFR-TKI resistance mechanisms.

OBJECTIVE

We characterized the genomic landscape of primary resistance to osimertinib among Hispanic patients with EGFR-mutant NSCLC.

METHODS

An observational longitudinal cohort study was conducted with two groups of patients, those with intrinsic resistance (cohort A) and those with long-term survival (cohort B). All patients were treated and followed between January 2018 and May 2022. All patients were assessed for Programmed Cell Death Ligand 1 (PD-L1) expression and Bcl-2-like protein 11 (BIM)/AXL mRNA expression before starting TKI. After 8 weeks of treatment, a liquid biopsy was performed to determine the presence of circulating free DNA (cfDNA), and next-generation sequencing (NGS) was used to identify mutations at the time of progression. In both cohorts, overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) were evaluated.

RESULTS

We found a homogeneous distribution of EGFR-sensitizing mutations in both cohorts. For cohort A, exon 21 mutations were more common than exon 19 deletions (ex19dels) for cohort B (P = 0.0001). The reported ORR for osimertinib was 6.3% and 100% for cohorts A and B, respectively (P = 0.0001). PFS was significantly higher in cohort B (27.4 months vs. 3.1 months; P = 0.0001) and ex19del patients versus L858R (24.5 months, 95% confidence interval [CI] 18.2-NR), vs. 7.6 months, 95% CI 4.8-21.1; P = 0.001). OS was considerably lower for cohort A (20.1 months vs. 36.0 months; P = 0.0001) and was better for patients with ex19del, no brain metastasis, and low tumor mutation burden. At the time of progression, more mutations were found in cohort A, identifying off-target alterations more frequently, including TP53, RAS, and RB1.

CONCLUSION

EGFR-independent alterations are common among patients with primary resistance to osimertinib and significantly impact PFS and OS. Our results suggest that among Hispanic patients, other variables associated with intrinsic resistance include the number of commutations, high levels AXL mRNA, and low levels of BIM mRNA, T790M de novo, EGFR p.L858R presence, and a high tumoral mutational burden.

Mechanisms of EGFR-TKI-Induced Apoptosis and Strategies Targeting Apoptosis in EGFR-Mutated Non-Small Cell Lung Cancer

Homeostasis is achieved by balancing cell survival and death. In cancer cells, especially those carrying driver mutations, the processes and signals that promote apoptosis are inhibited, facilitating the survival and proliferation of these dysregulated cells. Apoptosis induction is an important mechanism underlying the therapeutic efficacy of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) for EGFR-mutated non-small cell lung cancer (NSCLC). However, the mechanisms by which EGFR-TKIs induce apoptosis have not been fully elucidated. A deeper understanding of the apoptotic pathways induced by EGFR-TKIs is essential for the developing novel strategies to overcome resistance to EGFR-TKIs or to enhance the initial efficacy through therapeutic synergistic combinations. Recently, therapeutic strategies targeting apoptosis have been developed for cancer. Here, we review the state of knowledge on EGFR-TKI-induced apoptotic pathways and discuss the therapeutic strategies for enhancing EGFR-TKI efficiency. We highlight the great progress achieved with third-generation EGFR-TKIs. In particular, combination therapies of EGFR-TKIs with anti-vascular endothelial growth factor/receptor inhibitors or chemotherapy have emerged as promising therapeutic strategies for patients with EGFR-mutated NSCLC. Nevertheless, further breakthroughs are needed to yield an appropriate standard care for patients with EGFR-mutated NSCLC, which requires gaining a deeper understanding of cancer cell dynamics in response to EGFR-TKIs.

EGFR Inhibitors Plus Bevacizumab are Superior Than EGFR Inhibitors Alone as First-Line Setting in Advanced NSCLC With EGFR Mutations and BIM Deletion Polymorphisms (BIM-CLICaP)

PURPOSE

BIM activation is essential for epidermal growth factor receptor ( EGFR)-tyrosine kinase inhibitor (TKI)–triggered apoptosis in EGFR-mutant non–small-cell lung cancer (NSCLC). A deletion in the intron two of the BIM gene results in generation of alternatively spliced isoforms that impairs their apoptotic response to TKIs, conferring the NSCLC cells intrinsic resistance to these medications. Patients with both alterations have poor clinical evolution. The current study aimed to investigate the clinical efficacy and tolerability of EGFR-TKIs plus bevacizumab (Bev) versus EGFR-TKIs alone as first-line treatment in advanced NSCLC patients with EGFR mutations and BIM deletions ( BIMdel).

MATERIALS AND METHODS

A retrospective analysis was conducted. BIMdel was detected using polymerase chain reaction analysis and direct sequencing of DNA. BIM protein expression was investigated by immunohistochemistry, and BIM mRNA levels by reverse transcriptase-polymerase chain reaction. Clinical characteristics, overall survival, progression-free survival (PFS), overall response rate (ORR), and treatment-related adverse events were compared between both groups.

RESULTS

Thirty-three patients were included; 15 received EGFR-TKIs, and 18 received EGFR-TKIs plus Bev. The median age was 63 years, with a majority of recruited female patients. All included individuals had an Eastern Cooperative Oncology Group performance score of 2 or less. The addition of Bev resulted in a significantly higher ORR (94.4% v 40%, P > .001). Median PFS was longer with the use of the combination therapy (11.12 v 7.87 months; P = .001). Median overall survival tended to be longer in the EGFR-TKIs plus Bev (30.9 v 25.4 months; P = .06) but failed to reach statistical significance. Response in terms of both partial and complete as well as overall favorably affected PFS.

CONCLUSION

EGFR-TKIs plus Bev conferred a significantly higher ORR and PFS in advanced NSCLC patients with EGFR mutation and BIMdel. Further prospective studies are needed to validate these findings.

Prognostic Value of BIM Deletion in EGFR-Mutant NSCLC Patients Treated with EGFR-TKIs: A Meta-Analysis

BACKGROUND

Resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) is inevitable in EGFR-mutant non-small-cell lung cancer (NSCLC) patients. A germline 2903 bp deletion polymorphism of Bcl-2-like protein 11 (BIM) causes reduced expression of proapoptotic BH3-only BIM protein and blocks TKI-induced apoptosis of tumor cells. Yet the association between the deletion polymorphism and response to EGFR-TKI treatment remains inconsistent among clinical observations. Thus, we performed the present meta-analysis.

METHODS

Eligible studies were identified by searching PubMed, Embase, and ClinicalTrials.gov databases prior to March 31, 2021. Hazard ratios (HRs) and 95% confidence intervals (CIs) of progression-free survival (PFS) and overall survival (OS) and odds ratios (ORs) and 95% CIs of objective response rate (ORR) and disease control rate (DCR) were calculated by using a random effects model. Sensitivity, metaregression, and publication bias analyses were also performed.

RESULTS

A total of 20 datasets (3003 EGFR-mutant NSCLC patients receiving EGFR-TKIs from 18 studies) were included. There were 475 (15.8%) patients having the 2903-bp intron deletion of BIM and 2528 (84.2%) wild-type patients. BIM deletion predicted significantly shorter PFS (HR = 1.35, 95% CI: 1.10-1.64, P = 0.003) and a tendency toward an unfavorable OS (HR = 1.22, 95% CI: 0.99-1.50, P = 0.068). Patients with deletion polymorphism had lower ORR (OR = 0.60, 95% CI: 0.42-0.85, P = 0.004) and DCR (OR = 0.59, 95% CI: 0.38-0.90, P = 0.014) compared with those without deletion.

CONCLUSION

BIM deletion polymorphism may confer resistance to EGFR-TKIs and can be used as a biomarker to predict treatment response to EGFR-TKIs in EGFR-mutant NSCLC patients from Asian populations.

Update on molecular pathology and role of liquid biopsy in nonsmall cell lung cancer

Personalised medicine, an essential component of modern thoracic oncology, has been evolving continuously ever since the discovery of the epidermal growth factor receptor and its tyrosine kinase inhibitors. Today, screening for driver alterations in patients with advanced lung adenocarcinoma as well as those with squamous cell carcinoma and no/little history of smoking is mandatory. Multiplex molecular platforms are preferred to sequential molecular testing since they are less time- and tissue-consuming. In this review, we present the latest updates on the nine most common actionable driver alterations in nonsmall cell lung cancer. Liquid biopsy, a simple noninvasive technique that uses different analytes, mostly circulating tumour DNA, is an appealing tool that is used in thoracic oncology to identify driver alterations including resistance mutations. Additional roles are being evaluated in clinical trials and include monitoring the response to treatment, screening for lung cancer in high-risk patients and early detection of relapse in the adjuvant setting. In addition, liquid biopsy is being tested in immune-oncology as a prognostic, predictive and pharmacodynamic tool. The major limitation of plasma-based assays remains their low sensitivity when compared to tissue-based assays. Ensuring the clinical validity and utility of liquid biopsy will definitely optimise cancer care.

Screening for driver alterations in patients with advanced lung adenocarcinoma and those with squamous cell carcinoma and no/little smoking history is mandatory. Liquid biopsy is evolving constantly and will definitely improve outcomes in thoracic oncology.https://bit.ly/2XjuQrD

Targeting transcription of MCL-1 sensitizes HER2-amplified breast cancers to HER2 inhibitors

Human epidermal growth factor receptor 2 gene (HER2) is focally amplified in approximately 20% of breast cancers. HER2 inhibitors alone are not effective, and sensitizing agents will be necessary to move away from a reliance on heavily toxic chemotherapeutics. We recently demonstrated that the efficacy of HER2 inhibitors is mitigated by uniformly low levels of the myeloid cell leukemia 1 (MCL-1) endogenous inhibitor, NOXA. Emerging clinical data have demonstrated that clinically advanced cyclin-dependent kinase (CDK) inhibitors are effective MCL-1 inhibitors in patients, and, importantly, well tolerated. We, therefore, tested whether the CDK inhibitor, dinaciclib, could block MCL-1 in preclinical HER2-amplified breast cancer models and therefore sensitize these cancers to dual HER2/EGFR inhibitors neratinib and lapatinib, as well as to the novel selective HER2 inhibitor tucatinib. Indeed, we found dinaciclib suppresses MCL-1 RNA and is highly effective at sensitizing HER2 inhibitors both in vitro and in vivo. This combination was tolerable in vivo. Mechanistically, liberating the effector BCL-2 protein, BAK, from MCL-1 results in robust apoptosis. Thus, clinically advanced CDK inhibitors may effectively combine with HER2 inhibitors and present a chemotherapy-free therapeutic strategy in HER2-amplified breast cancer, which can be tested immediately in the clinic.

Concurrent Genetic Alterations and Other Biomarkers Predict Treatment Efficacy of EGFR-TKIs in EGFR-Mutant Non-Small Cell Lung Cancer: A Review

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) greatly improve the survival and quality of life of non-small cell lung cancer (NSCLC) patients with EGFR mutations. However, many patients exhibit de novo or primary/early resistance. In addition, patients who initially respond to EGFR-TKIs exhibit marked diversity in clinical outcomes. With the development of comprehensive genomic profiling, various mutations and concurrent (i.e., coexisting) genetic alterations have been discovered. Many studies have revealed that concurrent genetic alterations play an important role in the response and resistance of EGFR-mutant NSCLC to EGFR-TKIs. To optimize clinical outcomes, a better understanding of specific concurrent gene alterations and their impact on EGFR-TKI treatment efficacy is necessary. Further exploration of other biomarkers that can predict EGFR-TKI efficacy will help clinicians identify patients who may not respond to TKIs and allow them to choose appropriate treatment strategies. Here, we review the literature on specific gene alterations that coexist with EGFR mutations, including common alterations (intra-EGFR [on target] co-mutation, TP53, PIK3CA, and PTEN) and driver gene alterations (ALK, KRAS, ROS1, and MET). We also summarize data for other biomarkers (e.g., PD-L1 expression and BIM polymorphisms) associated with EGFR-TKI efficacy.

Resminostat, a histone deacetylase inhibitor, circumvents tolerance to EGFR inhibitors in EGFR-mutated lung cancer cells with BIM deletion polymorphism

Drug-tolerant cells are mediators of acquired resistance. BIM-intron2 deletion polymorphism (BIM-del) is one of the mechanisms underlying the resistance to epidermal growth factor tyrosine kinase inhibitor (EGFR-TKI)-mediated apoptosis that induces drug tolerance. Here, we investigated whether resminostat, a histone deacetylase inhibitor, circumvents BIM-del-associated apoptosis resistance. The human EGFR-mutated non-small cell lung cancer (NSCLC) cell line PC-9 and its homozygous BIM-del-positive variant (PC-9 BIMi2- / -), established by editing with zinc finger nuclease, were used. In comparison with PC-9 cells, PC-9 BIMi2- / - cells were less sensitive to apoptosis mediated by EGFR-TKIs such as gefitinib and osimertinib. The combined use of resminostat and an EGFR-TKI preferentially induced the expression of the pro-apoptotic BIM transcript containing exon 4 rather than that containing exon 3, increased the level of pro-apoptotic BIM protein (BIMEL), and stimulated apoptosis in vitro. In a subcutaneous tumor model derived from PC-9 BIMi2- / - cells, gefitinib monotherapy decreased tumor size but retained residual lesions, indicative of the presence of tolerant cells in tumors. The combined use of resminostat and gefitinib increased BIMEL protein level and induced apoptosis, subsequently leading to the remarkable shrinkage of tumor. These findings suggest the potential of resminostat to circumvent tolerance to EGFR-TKIs associated with BIM deletion polymorphism. J. Med. Invest. 67 : 343-350, August, 2020.

Phase I study of vorinostat with gefitinib in BIM deletion polymorphism/epidermal growth factor receptor mutation double-positive lung cancer

Patients with epidermal growth factor receptor (EGFR)‐mutated non‐small cell lung cancer (NSCLC) harboring BIM deletion polymorphism (BIM deletion) have poor responses to EGFR TKI. Mechanistically, the BIM deletion induces preferential splicing of the non‐functional exon 3‐containing isoform over the functional exon 4‐containing isoform, impairing TKI‐induced, BIM‐dependent apoptosis. Histone deacetylase inhibitor, vorinostat, resensitizes BIM deletion‐containing NSCLC cells to EGFR‐TKI. In the present study, we determined the safety of vorinostat‐gefitinib combination and evaluated pharmacodynamic biomarkers of vorinostat activity. Patients with EGFR‐mutated NSCLC with the BIM deletion, pretreated with EGFR‐TKI and chemotherapy, were recruited. Vorinostat (200, 300, 400 mg) was given daily on days 1‐7, and gefitinib 250 mg was given daily on days 1‐14. Vorinostat doses were escalated based on a conventional 3 + 3 design. Pharmacodynamic markers were measured using PBMC collected at baseline and 4 hours after vorinostat dose on day 2 in cycle 1. No dose‐limiting toxicities (DLT) were observed in 12 patients. We determined 400 mg vorinostat as the recommended phase II dose (RP2D). Median progression‐free survival was 5.2 months (95% CI: 1.4‐15.7). Disease control rate at 6 weeks was 83.3% (10/12). Vorinostat preferentially induced BIM mRNA‐containing exon 4 over mRNA‐containing exon 3, acetylated histone H3 protein, and proapoptotic BIM_EL protein in 11/11, 10/11, and 5/11 patients, respectively. These data indicate that RP2D was 400 mg vorinostat combined with gefitinib in BIM deletion/EGFR mutation double‐positive NSCLC. BIM mRNA exon 3/exon 4 ratio in PBMC may be a useful pharmacodynamic marker for treatment.

Gastrointestinal stromal tumor presenting as a rectovaginal septal mass: A case report and review of literature

INTRODUCTION

Gastrointestinal stromal tumors (GISTs) arising from the gynecological tract are extremely rare. A case of GIST with an unusual presentation as a vaginal mass is presented with comprehensive literature review, aiming to gain a better understanding of the diagnostic and treatment strategy of the disease.

PATIENT CONCERNS

A 78-year-old woman presented with persistent vaginal bleeding and difficulty in micturition. Although the tumor mass was diagnosed, the results of preoperative evaluations are uncertain.

DIAGNOSIS

Preoperative evaluation included the computed tomography examination (a 6.3×5.3 cm cervical mass lesion with rectal and vaginal invasion), colonoscopy (an external compression with an intact mucosa), tumor markers, and biopsy (spindle cell tumor). Postoperative histopathology confirmed the diagnosis of GIST.

INTERVENTIONS

Posterior exenteration with complete resection was performed. The patient received postoperative adjuvant imatinib therapy.

OUTCOMES

The patient has survived without the disease for more than 3 years.

CONCLUSION

It is still a challenge to diagnose GISTs in women with rectovaginal mass preoperatively. Efforts should be made, including a high suspicion and an assistance of immunohistochemistry. A precise diagnosis may offer a better surgical and treatment plan, especially on the preservation of reproductive organs and accessibility of targeted therapy.