Targeted therapy for leptomeningeal metastases in non-small cell lung cancer - Changing treatment paradigms

Clinical Outcomes of Patients with Non-Small Cell Lung Cancer Leptomeningeal Disease Following Receipt of EGFR-Targeted Therapy, Immune-Checkpoint Blockade, Intrathecal Chemotherapy, or Radiation Therapy Alone

BACKGROUND

EGFR-targeted therapy (ETT) and immune-checkpoint blockade (ICB) have shown promising results in treating NSCLC brain metastases (BM). However, little is known of their effect in treating leptomeningeal disease (LMD).

PATIENTS AND METHODS

This is a retrospective review of 80 patients diagnosed with NSCLC LMD from January 2014 to March 2021. Patients were grouped based on initial LMD treatment: radiotherapy (RT) alone, ETT, ICB, and intrathecal chemotherapy (ITC).

RESULTS

EGFR mutation was present in 22 patients (28%). Twenty patients had positive cytology in cerebrospinal fluid, while 60 patients were diagnosed based on MRI with clinical correlation. The RT alone group consisted primarily of whole brain radiation (n = 20; 77%), stereotactic radiation (n = 3; 12%), and palliative spine radiation (n = 2; 7%). There were no significant differences amongst the treatment groups in age, performance status, or neurologic symptoms. Overall, the 6-month overall survival (OS) and craniospinal progression free survival (CS-PFS) were 35% and 24%, respectively. The 6-month OS for the ETT, ICB, ITC, and RT alone groups was 64%, 33%, 57%, and 29% respectively (log-rank P = .026). The 6-month CS-PFS for the ETT, ICB, ITC, and RT alone groups was 43%, 33%, 29%, and 19% respectively (log-rank P = .049). Upon univariate analysis, receipt of ETT compared to RT alone reached significance for OS (HR 0.35, P = .006) and CS-PFS (HR 0.39, P = .013).

CONCLUSIONS

The prognosis for patients with NSCLC LMD remains poor overall. However, the receipt of ETT for patients with EGFR-positive disease was associated with improved outcomes.

GTPBP4: A New Therapeutic Target Gene Promotes Tumor Progression in Non-Small Cell Lung Cancer via EMT

Lung cancer has a complex etiology involving multiple regulatory systems. Uncertainty about the biology and evolution of lung cancer has made it difficult to improve its poor prognosis. To create efficient therapeutic targets and optimal molecular screening tools for lung cancer, the most important task seems to be to understand how it develops and progresses. The expression and regulation of GTPBP4 in non-small cell lung cancer (NSCLC) are not well understood. Using methods such as knocking down GTPBP4 in lung cancer cells and establishing a mouse lung cancer model, we found that the expression of GTPBP4 was upregulated in human lung adenocarcinoma cells and tissues, and that knocking down the expression of the GTPBP4 gene in A549 and Calu-1 lung adenocarcinoma cells can inhibit the proliferation of lung adenocarcinoma cells and reduce their invasion ability. The results of the mouse lung cancer model showed that the lung weight and the number of lung surface nodules decreased significantly in the LLC-GTPBP4 KO group. The mechanism by which GTPBP4 regulation affects the progression of lung adenocarcinoma may be related to the regulation of EMT. From this study, new research ideas emerge to explore GTPBP4 as a biomarker and therapeutic target for early diagnosis and treatment of lung cancer.

Long noncoding RNA POU6F2-AS1 regulates lung cancer aggressiveness through sponging miR-34c-5p to modulate KCNJ4 expression

It has been extensively reported that long noncoding RNAs (lncRNAs) were closely associated with multiple malignancies. The aim of our study was to investigate the effects and mechanism of lncRNA POU6F2-AS1 in lung adenocarcinoma (LADC).The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets provided us the information of LADC clinical samples. High-regulation of POU6F2-AS1 was presented in LADC tissues compared with adjacent normal tissues, which was correlated with poor outcome of LADC patients. Functional experiments in Calu-3 and NCI-H460 cells showed that POU6F2-AS1 significantly promoted LADC cell proliferation, colony formation, invasion and migration. Moreover, through online prediction, luciferase reporter assay and Pearson's correlation analysis, we found that POU6F2-AS1 may act as a competing endogenous RNA (ceRNA) of miR-34c-5p and facilitated the expression of potassium voltage-gated channel subfamily J member 4 (KCNJ4). The promoting effect of cell aggressiveness induced by POU6F2-AS1 was enhanced by KCNJ4, whilst was abrogated due to the overexpression of miR-34c-5p. Collectively, POU6F2-AS1 might function as a ceRNA through sponging miR-34c-5p to high-regulate KCNJ4 in LADC, which indicates that POU6F2-AS1 might be a promising therapeutic target with significant prognostic value for LADC treatment.

Leptomeningeal Carcinomatosis in Epithelial Ovarian Cancer: A Diagnostic Challenge

Leptomeningeal carcinomatosis (LCM), also known as neoplastic meningitis, is a rare entity. It is generally seen in solid tumors. Ovarian cancers can infrequently cause LCM. The clinical presentation is variable. Diagnosis is made by a lumbar puncture that shows malignant cells in the cerebrospinal fluid (CSF) and usually correlates with imaging findings. Given the low individual sensitivities of lumbar puncture (55%) and magnetic resonance imaging (70%), it is recommended to combine both modalities for optimal diagnostic results. Treatment options vary depending on the type of primary carcinoma, however, the prognosis is guarded. We report a case of LCM in a patient with stage IV epithelial ovarian cancer in remission, which became a diagnostic challenge due to a lack of imaging findings.

Classification of Leptomeningeal Metastases from Solid Organ Malignancies and Clinical Outcomes: Series from a Cancer Research Centre

Leptomeningeal metastases (LMs) are a critical neurological manifestation of solid organ malignancies. Early diagnosis and prompt treatment is necessary to improve outcomes. We classified LM on the basis of cytological or histological and imaging studies. A total of 14 patients of LM from solid organ malignancies diagnosed between July 2016 and December 2018 were included in the series. LM was classified based on cerebrospinal fluid (CSF) cytology and magnetic resonance imaging (MRI) findings. Survival outcomes were noted. LM from carcinoma of breast and lung accounted for most of the cases. Type I LM was seen in 12 patients while 2 accounted for type II LM. Median overall survival (OS) was 40.5 days. Newer-generation tyrosine kinase inhibitor (TKI) therapy seems promising in the treatment of LM. Classification of LM based on cytology/histology and imaging findings allows early diagnosis and treatment. Newer-generation TKIs should be used for the treatment of LM if indicated.

Identification of Cerebrospinal Fluid MicroRNAs Associated With Leptomeningeal Metastasis From Lung Adenocarcinoma

Background: Leptomeningeal metastasis (LM) has frequently been observed in patients with lung adenocarcinoma. So far, its diagnosis and disease course monitoring are still extremely difficult. Moreover, there is no effective treatment regimen for LM due to a lack knowledge on the molecular mechanism of LM. This study aimed to identify LM-related cerebrospinal fluid (CSF) miRNAs, which have potential value for diagnosing and monitoring LM and exploring the molecular mechanism. Methods: CSF miRNAs were screened and verified by microarray analysis and quantitative real-time PCR (qRT-PCR) in LM patients with lung adenocarcinoma and non-LM controls, and the diagnostic performance of candidate miRNAs was evaluated. Then, candidate miRNAs in matched CSF samples from LM patients at diagnosis, after initial therapy, at relapse, and after salvage therapy, were analyzed to assess the relationship between CSF miRNAs and LM disease course. The effect of candidate miRNAs on proliferation, invasion, and migration of lung adenocarcinoma cell lines was assessed. The targeted genes of the candidate miRNA were predicted by TargetScan, miRDB, and miRTarbase online analysis tools. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to analyze the functional categories of predicted target genes. Results: CSF miR-7975, miR-7977, and miR-7641 were screened and verified to be statistically significantly up-regulated in LM patients compared to non-LM controls. The three miRNAs, when combined, exhibited optimal diagnostic performance. Longitudinal data of CSF miR-7975 and miR-7977 correlated well with clinical courses of LM. Overexpression of miR-7977 promoted proliferation, migration, and invasion of lung adenocarcinoma cells. Moreover, 385 targeted genes of miR-7977 were predicted and were involved in various pathways related to cancer metastasis. Conclusions: This study offers insights for future research of CSF miRNAs as robust tools for diagnosing and monitoring LM. It also reveals a novel pathway for exploration of underlying mechanisms of LM.

Integration of stereotactic radiosurgery or whole brain radiation therapy with immunotherapy for treatment of brain metastases

The prognosis of brain metastases (BM) is traditionally poor. BM are mainly treated by local radiotherapy, including stereotactic radiosurgery (SRS) or whole brain radiation therapy (WBRT). Recently, immunotherapy (i.e., immune checkpoint inhibitors, ICI) has demonstrated a survival advantage in multiple malignancies commonly associated with BM. Individually, radiotherapy and ICI both treat BM efficiently; hence, their combination seems logical. In this review, we summarize the existing preclinical and clinical evidence that supports the applicability of radiotherapy as a sensitizer of ICI for BM. Further, we discuss the optimal timing at which radiotherapy and ICI should be administered and review the safety of the combination therapy. Data from a few clinical studies suggest that combining SRS or WBRT with ICI simultaneously rather than consecutively potentially enhances brain abscopal-like responses and survival. However, there is a lack of conclusion about the definition of "simultaneous"; the cumulative toxic effect of the combined therapies also requires further study. Thus, ongoing and planned prospective trials are needed to further explore and validate the effect, safety, and optimal timing of the combination of immunotherapy with radiotherapy for patients with BM.

Prognostic implications of epidermal growth factor receptor variant III expression and nuclear translocation in Chinese human gliomas

Objective

To determine the prognostic implications and clinical significance of epidermal growth factor receptor variant III (EGFRvIII) expression and EGFRvIII nuclear translocation in Chinese human gliomas.

Methods

We retrospectively examined EGFRvIII expression and EGFRvIII nuclear translocation using immunohistochemistry in specimens of 240 Chinese patients with glioma, including 84 World Health Organization (WHO) II gliomas, 84 WHO III gliomas and 72 glioblastomas (WHO IV). Factors that correlated with EGFRvIII and EGFRvIII nuclear translocation expression were analyzed by the Chi-square test. Kaplan-Meier methodology and Cox regression were used for the survival analysis.

Results

Log-rank tests showed that patient age, Karnofsky performance scale (KPS) score, tumor grade, EGFRvIII expression, EGFRvIII nuclear translocation, 1p/19q codeletion, isocitrate dehydrogenase (IDH) mutation, Ki-67 labeling index and O6-methylguanine-DNA methyltransferase (MGMT) status (P<0.05) were significantly correlated with overall survival (OS) time. Multivariate Cox regression analysis revealed that patient age, tumor grade, EGFRvIII nuclear translocation, 1p/19q codeletion, and IDH mutation (P<0.05) were significantly correlated with OS. Patients with a high level of EGFRvIII nuclear translocation (≥7%) had both significantly shorter OS [hazard ratio (HR): 1.920, 95% confidence interval (95% CI): 1.228−3.003, P=0.004] and progression-free survival (PFS) times (HR: 1.661, 95% CI: 1.116−2.471, P=0.012) than those with a low level of EGFRvIII nuclear translocation (<7%).

Conclusions

A high level of EGFRvIII nuclear translocation in glioma is an independent factor indicating a poor prognosis, but EGFRvIII expression is not an independent clinical prognostic factor. The level of EGFRvIII nuclear translocation maybe a novel and crucial prognostic biomarker in glioma.

Overexpression of KCNJ4 correlates with cancer progression and unfavorable prognosis in lung adenocarcinoma

KCNJ4 (potassium voltage-gated channel subfamily J member 4) belongs to the inward rectifier potassium channel family, which is inhibited by novel anticancer agents. However, the biologic significance of KCNJ4 in lung adenocarcinoma (LADC) is largely unknown. Therefore, in this study, we evaluated the expression, clinical correlation, and prognostic value of KCNJ4 in LADC and normal lung tissues according to data from The Cancer Genome Atlas datasets. A small interfering RNA (siRNA)-mediated technology was used to inhibit the expression level of KCNJ4. Cell counting kit-8 and plate colony formation assays were used to measure cell proliferation. Wound-healing and transwell assays were applied to detect cell mobility and metastasis. Quantitative real-time polymerase chain reaction and western blot analysis were used to examine messenger RNA and protein expressions, respectively. It was found that KCNJ4 was significantly upregulated in LADC tissues and cells. The high level of KCNJ4 predicted shorter overall survival and was identified as an independent prognostic factor in patients with LADC. siRNA-mediated KCNJ4 silencing impeded LADC cell proliferation, migration, and invasion. Knockdown of KCNJ4 suppressed the expression of phosphorylated mitogen-activated protein kinase/extracellular signal regulated kinase (p-MEK) and phosphorylated extracellular signal-regulated kinase (p-ERK). Collectively, these results shed some light on the contribution of KCNJ4 functioning as a significant player in LADC, implying that KCNJ4 might be a valuable prognostic biomarker and a potential therapeutic target for LADC treatment.

An Acquired Epidermal Growth Factor Receptor T790M Mutation after the Addition of Bevacizumab to Preceding Erlotinib Monotherapy in a Lung Cancer Patient with Leptomeningeal Metastases

A 53-year-old man with advanced lung adenocarcinoma harboring epidermal growth factor receptor (EGFR) exon 19 deletion received erlotinib. After 12 months of disease control with erlotinib monotherapy, leptomeningeal metastases (LM) occurred. A cerebrospinal fluid examination demonstrated a pre-existing EGFR exon 19 deletion. Bevacizumab was combined with erlotinib, and the LM improved. After six months of combination therapy, however, the LM was exacerbated. A re-examination of the cerebrospinal fluid revealed a T790M mutation and exon 19 deletion. Osimertinib was administered, and the LM improved. The combination of bevacizumab and erlotinib was effective for erlotinib-resistant LM and resulted in the expression of a newly acquired T790M mutation, which enabled successful treatment with osimertinib.