Clinical significance of apoptotic index in non-small cell lung cancer: correlation with p53, mdm2, pRb and p21WAF1/CIP1 protein expression

Genome-wide CRISPR/Cas9 screening for therapeutic targets in NSCLC carrying wild-type TP53 and receptor tyrosine kinase genes

Background

Targeted drugs have greatly improved the therapeutic outcome of non‐small cell lung cancer (NSCLC) patients compared with conventional chemotherapy, whereas about one‐third of patients are so far not suitable for targeted therapy due to lack of known driver oncogenes such as a mutated receptor tyrosine kinase (RTK) genes. In this study, we aimed to identify therapeutic targets for this subgroup of NSCLC patients.

Methods

We performed genome‐wide CRISPR/Cas9 screens in two NSCLC cell lines carrying wild‐type TP53 and receptor tyrosine kinase (wtTP53‐RTK) genes using a GeCKO v2.0 lentiviral library (containing 123411 sgRNAs and targeting 19050 genes). MAGeCKFlute was used to analyse and identify candidate genes. Genetic perturbation and pharmacological inhibition were used to validate the result in vitro and in vivo.

Results

The Genome‐wide CRISPR/Cas9 screening identified MDM2 as a potential therapeutic target for wtTP53‐RTK NSCLC. Genetic and pharmacological inhibition of MDM2 reduced cell proliferation and impaired tumour growth in the xenograft model, thus confirming the finding of the CRISPR/Cas9 screening. Moreover, treatment by a selective MDM2 inhibitor RG7388 triggered both cell cycle arrest and apoptosis in several NSCLC cell lines. Additionally, RG7388 and pemetrexed synergistically blocked the cell proliferation and growth of wtTP53‐RTK tumours but had limited effects for other genotypes.

Conclusions

We identified MDM2 as an essential gene and a potential therapeutic target in wtTP53‐RTK NSCLC via a genome‐wide CRISPR/Cas9 screening. For this subgroup, treatment by RG7388 alone or by its combination with pemetrexed resulted in significant tumour inhibition.

Effects of zerumbone on proliferation and apoptosis of esophageal cancer cells and on P53 and Bcl-2 expression levels

The effects of zerumbone on the proliferation and apoptosis of esophagus cancer cells and on the P53 and Bcl-2 expression levels were studied. The esophagus cancer EC-109 cells were cultured and inoculated. The effect of zerumbone on proliferation of EC-109 cells was detected via the Cell Counting Kit-8 (CCK-8) method. Cell apoptosis was detected via TdT-mediated dUTP nick end-labeling (TUNEL) staining. Moreover, the mRNA expression levels of P53 and Bcl-2 were detected via reverse transcription-polymerase chain reaction (RT-PCR), and the protein expression levels of P53 and Bcl-2 were evaluated via western blotting. CCK-8 detection results showed that compared with control group, zerumbone in different concentrations could inhibit the activity of EC-109, and the proliferation inhibition rate was significantly increased in a concentration-dependent manner with the increase of concentration. TUNEL staining showed that cell apoptosis gradually occurred in administration group, and the number of apoptotic cells was increased in a concentration-dependent manner with the increase of concentration. RT-PCR detection results showed that the mRNA expression level of P53 in administration group was significantly increased compared with that in control group, but that of Bcl-2 was significantly decreased. Western blotting showed that the protein expression level of Bcl-2 in administration group in different concentrations was significantly increased with the increase of zerumbone concentration, but that of Bcl-2 was significantly decreased in a concentration-dependent manner. Zerumbone can inhibit the proliferation and induce apoptosis of esophageal cancer EC-109 cells, and its induction of apoptosis may be realized through upregulating the mRNA expression of P53 and downregulating the mRNA expression of Bcl-2, and upregulating the protein expression of P53 and downregulating the protein expression of Bcl-2.

Apoptotic Tumor Cell-Derived Extracellular Vesicles as Important Regulators of the Onco-Regenerative Niche

Cells undergoing apoptosis produce heterogeneous populations of membrane delimited extracellular vesicles (Apo-EVs) which vary not only in size—from tens of nanometers to several microns—but also in molecular composition and cargo. Apo-EVs carry a variety of potentially biologically active components, including small molecules, proteins, and nucleic acids. Larger forms of Apo-EVs, commonly termed “apoptotic bodies,” can carry organelles, such as mitochondria and nuclear fragments. Molecules displayed on the surface of extracellular vesicles (EVs) can contribute substantially to their size, as well as their functions. Thus far, relatively little is known of the functional significance of Apo-EVs apart from their roles in fragmentation of dying cells and indicated immunomodulatory activities. Here, we discuss EV production by dying tumor cells and consider the possible roles of Apo-EVs in a cell death-driven sector of the tumor microenvironment known as the onco-regenerative niche (ORN). We propose that tumor-derived Apo-EVs are significant vehicles of the ORN, functioning as critical intercellular communicators that activate oncogenic tissue repair and regeneration pathways. We highlight important outstanding questions and suggest that Apo-EVs may harbor novel therapeutic targets.

Eukaryotic initiation factor-4E and cyclin D1 expression associated with patient survival in lung cancer

Eukaryotic initiation factor 4E (eIF4E) and cyclin D1, two important factors in cell-cycle progression, play key roles in the carcinogenesis of varied human cancers. However, eIF4E expression in non-small-cell lung cancer (NSCLC) and its association with cyclin D1 has received little investigation. One hundred forty-seven subjects with primary NSCLC, with long-term follow-up and essential clinicopathologic parameters (including age, sex, tumor grade, tumor stage, smoking history, performance status, weight loss, histology grade, and survival data) were evaluated based on expression of eIF4E and cyclin D1. Immunohistochemical analysis was performed using monoclonal antibodies against eIF4E and cyclin D1. While 134 of 147 cases (91%) were positive for eIF4E, 82 of 136 cases (63%) were positive for cyclin D1. Western blot results were consistent with those illustrated by immunohistochemistry. While eIF4E(+) correlated with significantly shorter patient survival (P = .03), cyclin D1(+) correlated with longer patient survival (P = .01). Assessment of coexpression of cyclin D1 and eIF4E shows greater value in determining the prognosis of NSCLC: patients with eIF4E(+)/cyclin D1(-) have poorer outcome, those with eIF4E(-)/cyclin D1(+) have a more favorable outcome, and those with eIF4E(+)/cyclin D1(+) have an intermediate outcome (P = .02). The negative effect on survival in patients with eIF4E(+) suggests its potential prognostic role in NSCLC. These results warrant further investigation to explore the value of eIF4E in identifying patients with aggressive disease for adjuvant treatments.

Prognostic value of the apoptotic index analysed jointly with selected cell cycle regulators and proliferation markers in non-small cell lung cancer

In a previous small series of surgically treated non-small cell lung cancer patients (NSCLC), we found that higher apoptotic index (AI) negatively influenced survival (Dworakowska D, Jassem E, Jassem J, Karmolinski A, Dworakowski R, Wirth T, et al. Clinical significance of apoptotic index in non-small cell lung cancer: correlation with p53, mdm2, pRb and p21WAF1/CIP1 protein expression. J Cancer Res Clin Oncol 2005; 131:617-623.). In this study we attempted to verify our previous finding in larger group of 170 NSCLC cases, additionally correlating AI to selected cell cycle regulators as well as a proliferation marker. Apoptosis was assessed with the use of the TUNEL technique, whereas the expression of p53, pRb, mdm2, p21(WAF1/CIP1), cyclin D1 and PCNA were assessed immunohistochemically. The mean and the median AI was 12 and 8, respectively. The expression of p53, pRb, mdm2, p21(WAF1/CIP1) proteins and cyclin D1 was found in 47%, 71%, 37%, 65% and 40% of cases, respectively. The mean and the median PCNA labeling index (PCNA LI) was 34 and 35, respectively. AI was not correlated with any patient characteristic or other tumor markers. In uni- and multivariate analysis AI, analysed separately or jointly with cell cycle regulators and PCNA LI, did not influence disease-free or over-all survival. However, patients with "very high AI/very high PCNA LI" had a particularly poor prognosis (P=0.001). Patients with "very low AI/negative pRb" phenotype survived for a shorter time in comparison to others (P=0.04). In addition, patients with the highest PCNA LI had a worse outcome in comparison to patients with the lowest PCNA LI (P=0.04), especially those with concomitant p53 protein expression (P=0.026) or lacking pRb protein expression (P=0.04). This study demonstrates that joint analysis of several factors involved in apoptosis, proliferation and cell cycle regulation, but not AI alone, might provide additional prognostic information in NSCLC patients.

Clinical and molecular responses in lung cancer patients receiving Romidepsin

PURPOSE

Our preclinical experiments indicated that Romidepsin (Depsipeptide FK228; DP) mediates growth arrest and apoptosis in cultured lung cancer cells. A phase II trial was done to examine clinical and molecular responses mediated by this histone deacetylase inhibitor in lung cancer patients.

EXPERIMENTAL DESIGN

Nineteen patients with neoplasms refractory to standard therapy received 4-h DP infusions (17.8 mg/m(2)) on days 1 and 7 of a 21-day cycle. Each full course of therapy consisted of two identical 21-day cycles. Plasma DP levels were evaluated by liquid chromatography-mass spectrometry techniques. A variety of molecular end points were assessed in tumor biopsies via immunohistochemistry techniques. Long oligo arrays were used to examine gene expression profiles in laser-captured tumor cells before and after DP exposure, relative to lung cancer cells and adjacent normal bronchial epithelia from patients undergoing pulmonary resections.

RESULTS

Nineteen patients were evaluable for toxicity assessment; 18 were evaluable for treatment response. Myelosuppression was dose limiting in one individual. No significant cardiac toxicities were observed. Maximum steady-state plasma DP concentrations ranged from 384 to 1,114 ng/mL. No objective responses were observed. Transient stabilization of disease was noted in nine patients. DP enhanced acetylation of histone H4, increased p21 expression in lung cancer cells, and seemed to shift global gene expression profiles in these cells toward those detected in normal bronchial epithelia.

CONCLUSION

Although exhibiting minimal clinical efficacy at this dose and schedule, DP mediates biological effects that may warrant further evaluation of this histone deacetylase inhibitor in combination with novel-targeted agents in lung cancer patients.

EGFR, TTF-1 and Mdm2 expression in stage III non-small cell lung cancer: a positive association

New biological factors have not been extensively studied in stage III NSCLC as yet. The aim of this retrospective study was to assess the association between the expression and the prognostic role on survival of four biological markers in stage III NSCLC. Clinical characteristics were retrieved from the patients charts. EGF-R, Mdm2, p53 and TTF-1 expressions were evaluated by immunohistochemistry by three independent observers. Cox multivariate model was used to assess the impact of clinical and biological factors on patients' survival. A total of 84 stage III NSCLC patients, treated between 03/1987 and 08/2003, were included in the study. There was a statistically significant association between the expression of TTF-1 and EGFR (p=0.01) or TTF-1 and Mdm2 (p=0.04). Positive expressions for EGFR or TTF-1 were almost mutually exclusive. The status EGFR+/TTF-1--was mainly found in squamous cell carcinoma (18 among 19tumours). In multivariate analysis, only treatment with curative intent was independently associated with better survival (p=0.0004). In stage III NSCLC, there was a significant association between TTF-1 and EGFR or TTF-1 and Mdm2. The status EGFR+/TTF-1--was associated with squamous cell carcinoma.

Influence of apoptosis and cell cycle regulator proteins on chemotherapy response and survival in stage IIIA/IIIB NSCLC patients

BACKGROUND

Prognosis for non-small cell lung cancer (NSCLC) patients is very poor. Prediction of the response to treatment in individual patients may be possible using molecular biological alterations such as clinical biomarkers. We investigated the predictive value of apoptosis and cell cycle regulator proteins for neoadjuvant chemotherapy response in stage IIIA/IIIB NSCLC patients.

METHODS

We evaluated p53, bcl-2, p21WAF1/CIP1, p27Kip1, and Ki67 immunohistochemical expression and apoptotic index in mediastinal lymph node metastases from 23 IIIA and 10 IIIB NSCLC patients before treatment with neoadjuvant platinum-based chemotherapy. Univariate analysis was performed to evaluate the relationship between protein expression and survival or time to progression (TTP).

RESULTS

Median follow-up was 25 months (range, 4-112), median TTP was 11 months (range, 0-112), and median overall survival was 22 months (range, 4-112). Of 32 assessable patients, 18 (56%) had stable disease, 12 (38%) had a PR, and two (6%) had progressive disease. Of the 22 patients assessable for pN2 following chemotherapy, 16 (77%) were positive. Univariate analysis showed that shorter TTP correlated with progressive disease (p = 0.000), positive pN2 after chemotherapy (p = 0.026), high Ki67 (p = 0.022), and high p21WAF1/CIP1 (p = 0.038).

CONCLUSION

Our results suggest that in IIIA/IIIB NSCLC patients, a high level of p21WAF1 expression in mediastinal lymph node metastases before neoadjuvant platinum-based chemotherapy is associated with a poor outcome. Our results suggest that expression of p21WAF1, which plays a role in preventing apoptosis, may be significant when selecting chemotherapy for NSCLC patients.

Immunohistochemical markers of prognosis in non-small cell lung cancer: a review and proposal for a multiphase approach to marker evaluation

Characteristics of the tumour that affect and predict the survival outcome of patients with cancer are prognostic markers for cancer. In non-small cell lung carcinoma (NSCLC), stage is the main determinant of prognosis and the basis for deciding options for treatment. Patients with early-stage tumour are treated by complete surgical resection, which is curative in 40-70% of patients. That there are other factors important in determining the biology of these tumours, especially genes that have a role in metastasis, is indicated. Such factors could potentially be used to further classify patients into groups according to substages that may be treated differently. During the past decade, a large number of proteins that are putatively important in carcinogenesis and cancer biology have been studied for their prognostic value in NSCLC, but none of them have been proved to be sufficiently useful in clinical diagnosis. Several markers (epidermal growth factor receptor, human epidermal growth factor receptor 2, Ki-67, p53 and Bcl-2) have been studied exhaustively. Ki-67, p53 and Bcl-2 are suggested to be important but weak prognostic markers, by meta-analyses of the results. Cyclin E, vascular endothelial growth factor A, p16(INK4A), p27(kip1) and beta-catenin are promising candidates, but require further study in large randomised clinical trial samples by using standardised assays and scoring systems. Some issues and inconsistencies in the reported studies to date are highlighted and discussed. A guideline for a multi-phase approach for conducting future studies on prognostic immunohistochemistry markers is proposed here.