Prognostic significance of p27KIP1 expression in resected non-small cell lung cancers: analysis in combination with expressions of p16INK4A, pRB, and p53

Effect of p27 gene combined with Pientzehuang ([characters: see text]) on tumor growth in osteosarcoma-bearing nude mice

OBJECTIVE

To observe the effect of p27 gene recombinant adenovirus combined with Chinese medicine Pientzehuang ([characters: see text]) on the growth of xenografted human osteosarcoma in nude mice.

METHODS

Tissue transplantation was used to construct the orthotopic model of human osteosarcoma Saos-2 cell in nude mice. Thirty tumor-bearing nude mice were randomly divided into 5 groups with 6 mice in each group: blank control group (model of osteosarcoma), empty vector group (recombinant adeno-associated virus-multiple cloning site), Pientzehuang group, p27 gene group and combined treatment group (p27 gene combined with Pientzehuang). The effect of combined treatment on human osteosarcoma was analyzed through the tumor formation, tumor volume and inhibition rate of tumor growth. The expression of p27 was measured by immunohistochemical staining and Western blot.

RESULTS

The orthotopic model of osteosarcoma in nude mice was successfully constructed. The general appearance of tumor-bearing nude mice in Pientzehuang and p27 gene groups was markedly improved compared with the blank control group; and in the combined treatment group it was significantly improved compared with the Pientzehuang and p27 gene groups. The tumor growth in the Pientzehuang and p27 gene groups was significantly inhibited compared with the blank control group P<0.05); while in the combined treatment group it was markedly inhibited compared with the Pientzehuang and p27 gene groups (P<0.05). The rates of tumor growth inhibition were 34.1%, 56.5% and 63.8% in the Pientzehuang, p27 gene and combined treatment groups, respectively. Meanwhile, the protein expression of p27 gene in the p27 gene group was significantly increased compared with the blank control group (P<0.05); and it was significantly increased in the combined treatment group compared with the p27 gene and Pientzehuang groups (P<0.05).

CONCLUSION

p27 gene introduced by adenovirus combined with Pientzehuang can inhibit the growth of human osteosarcoma cell Saos-2 in nude mice.

SIRT1 inactivation evokes antitumor activities in NSCLC through the tumor suppressor p27

P27(Kip1) (CDKN1B) regulates cellular proliferation and senescence, and p27(Kip1) deficiency in cancer is strongly correlated with poor prognosis of multiple cancer types. Understanding the mechanism of p27(Kip1) loss in cancer and the consequences of restoring p27(Kip1) levels is therefore critical for effective management during therapy. Here, SIRT1, a class III histone deacetylase (HDAC), is identified as an important regulator of p27(Kip1) expression. Mechanistically, SIRT1 reduces p27(Kip1) expression by decreasing p27(Kip1) protein stability through the ubiquitin-proteasome pathway. In addition, SIRT1 silencing suppresses non-small cell lung cancer (NSCLC) proliferation and induces senescence in a p27(Kip1)-dependent manner. Furthermore, SIRT1 silencing dramatically suppresses tumor formation and proliferation in two distinct NSCLC xenograft mouse models. Collectively, these data demonstrate that not only SIRT1 is an important regulator of p27(Kip1) but also SIRT inhibition induces senescence and antigrowth potential in lung cancer in vivo.

IMPLICATIONS

SIRT1 is a key regulator of p27 protein levels and SIRT1 inhibition is a viable strategy for NSCLC therapy by means of p27 reactivation.

High p27 expression is associated with a better prognosis in East Asian non-small cell lung cancer patients

BACKGROUND

The role of the anti-apoptotic protein p27 in non-small cell lung cancer (NSCLC) remains controversial. To clarify its association with survival in NSCLC, we performed a systematic review of the literature with meta-analysis.

METHODS

Trials were selected for further analysis if they provided an independent assessment of p27 in NSCLC and reported the analysis of survival data based on p27 status. A total of 11 trials, which comprised 1646 patients, provided sufficient information for the meta-analysis. Sensitivity analyses were conducted using histology, disease stage and ethnicity.

RESULTS

The combined hazard ratio (HR) of 1.50 (95% CI=1.15-1.97; P<0.001 for heterogeneity) suggested that high p27 expression has a favorable impact on survival. When the studies were restricted to those of East Asian populations, patients that expressed high levels of p27 showed a better survival rate (HR 1.73, 95% CI=1.36-2.21; P=0.169 for heterogeneity) than those that did not express high levels of p27. In addition, the heterogeneity and publication bias disappeared.

CONCLUSION

In NSCLC, high p27 expression is associated with a better prognosis among East Asians.

Potentially functional polymorphisms in cell cycle genes and the survival of non-small cell lung cancer in a Chinese population

The cell cycle governs the proliferation and growth of cells and is strictly controlled by some regulators including cyclins, CDKs and CKIs. Germ-line and somatic mutations in cell cycle genes were frequently observed in a subset of cancers including non-small cell lung cancer (NSCLC). In this study, we hypothesized that potentially functional single nucleotide polymorphisms (SNPs) in cell cycle genes may contribute to the prognosis of NSCLC in China. 54 potentially functional polymorphisms in key cell cycle genes (CDK1, CDK2, CDK4, CDK6, CDK7, CCND1, CCND2, CCND3, CCNE1, CCNA1, CCNA2, CCNB1, CCNH, p15, p16, p18, p19, p21, p27, Cdc25A and Cdc25B) were genotyped by using Illumina SNP genotyping platform to evaluate their associations with survival of NSCLC in a clinical cohort of 568 patients. We found that p18 rs3176447 variant genotypes were significantly associated with the decreased risk of death of NSCLC patients (adjusted HR=0.74, 95% CI=0.57-0.97 in an additive model; adjusted HR=0.76, 95% CI=0.55-0.97 in a dominant model); however, p21 rs2395655 variant genotypes were significantly associated with the increased risk of death (adjusted HR=1.21, 95% CI=1.02-1.42 in an additive model; adjusted HR=1.38, 95% CI=1.07-1.78 in a recessive model). Furthermore, the combined effect of unfavorable genotypes for these two SNPs was more prominent in patients with squamous cell carcinoma, late stage and without chemo- or radio-therapy. Although the exact biological function remains to be explored, our findings suggest possible association of polymorphisms of p18 and p21 with the prognosis of NSCLC in a Chinese population. Further large and functional studies are needed to confirm our findings.

EMMPRIN and fascin expression in non-small cell lung carcinoma

Fascin and EMMPRIN (CD 147) have a demonstrated relationship with the invasion and progression of many tumors. The aim of this study was to analyze fascin and EMMPRIN expression in non-small cell lung carcinoma and their relationship with clinicopathologic features. Fascin and EMMPRIN expression levels were investigated via the immunohistochemistry of paraffin-embedded tissues of 64 patients with non-small cell lung carcinoma, including 46 squamous cell carcinoma and 18 adenocarcinoma patients. The patients were scored on the basis of staining extent and intensity, and were then assigned a combined score. Fascin expression was present in 44 of 46 (95.6%) patients with SCC and 16 of 18 (88.8%) patients with adenocarcinoma. There was a significant correlation between fascin expression and tumor stage in the SCC and adenocarcinoma groups. EMMPRIN expression was observed in all patients with SCC (46 of 46, 100%) and 16 of 18 (88.8%) patients with adenocarcinoma. There was significant correlation between EMMPRIN expression and both tumor stage and diameter in the SCC group, but not in the adenocarcinoma group. This study revealed that high levels of fascin and EMMPRIN expression may indicate the importance of their roles in the progression of non-small cell lung carcinoma and they could be used as prognostic marker for these tumors.

p27: a barometer of signaling deregulation and potential predictor of response to targeted therapies

Phosphorylation of the cyclin-dependent kinase inhibitor p27 by upstream mitogenic signaling pathways regulates its stability, localization, and biological function. In human cancers, loss of the antiproliferative action of p27 can arise through reduced protein levels and/or cytoplasmic mislocalization, leading to increased cell proliferation and/or cell migration, respectively. Reduced p27 expression levels and p27 mislocalization have potential prognostic and therapeutic implications in various types of human cancers. This review highlights mechanisms of functional deregulation of p27 by oncogenic signaling that provide an important molecular rationale for pathway targeting in cancer treatment.

Gene expression profiling for molecular distinction and characterization of laser captured primary lung cancers

Methods

We examined gene expression profiles of tumor cells from 29 untreated patients with lung cancer (10 adenocarcinomas (AC), 10 squamous cell carcinomas (SCC), and 9 small cell lung cancer (SCLC)) in comparison to 5 samples of normal lung tissue (NT). The European and American methodological quality guidelines for microarray experiments were followed, including the stipulated use of laser capture microdissection for separation and purification of the lung cancer tumor cells from surrounding tissue.

Results

Based on differentially expressed genes, different lung cancer samples could be distinguished from each other and from normal lung tissue using hierarchical clustering. Comparing AC, SCC and SCLC with NT, we found 205, 335 and 404 genes, respectively, that were at least 2-fold differentially expressed (estimated false discovery rate: < 2.6%). Different lung cancer subtypes had distinct molecular phenotypes, which also reflected their biological characteristics. Differentially expressed genes in human lung tumors which may be of relevance in the respective lung cancer subtypes were corroborated by quantitative real-time PCR.

Genetic programming (GP) was performed to construct a classifier for distinguishing between AC, SCC, SCLC, and NT. Forty genes, that could be used to correctly classify the tumor or NT samples, have been identified. In addition, all samples from an independent test set of 13 further tumors (AC or SCC) were also correctly classified.

Conclusion

The data from this research identified potential candidate genes which could be used as the basis for the development of diagnostic tools and lung tumor type-specific targeted therapies.

The Cdk inhibitor p27 in human cancer: prognostic potential and relevance to anticancer therapy

The cyclin-dependent kinase (Cdk) inhibitor p27 (also known as KIP1) regulates cell proliferation, cell motility and apoptosis. Interestingly, the protein can exert both positive and negative functions on these processes. Diverse post-translational modifications determine the physiological role of p27. Phosphorylation regulates p27 binding to and inhibition of cyclin-Cdk complexes, its localization and its ubiquitin-mediated proteolysis. In cancers, p27 is inactivated through impaired synthesis, accelerated degradation and by mislocalization. Moreover, studies in several tumour types indicate that p27 expression levels have both prognostic and therapeutic implications.

Prognostic Model of Stage II Non-Small Cell Lung Cancer by a Discriminant Analysis of the Immunohistochemical Protein Expression

PURPOSE

We aimed to identify the key proteins that influence the prognosis of non-small cell lung cancer (NSCLC) using protein expression profiles of previously known prognostic markers.

METHODS

Thirty-one cases of Stage II NSCLC with 5-year follow-up data were selected. Tissue microarrays (TMA) and immunohistochemistry were used to make protein expression profiles of 18 previously reported immunohistochemical prognostic markers and their value in NSCLC was statistically re-evaluated by a discriminant analysis.

RESULTS

For the discriminant analysis using marker protein expression profiles, we selected three significant markers, TTF-1, RCAS1 and c-MET, to evaluate each patient's 5-year survival. The requested discriminant function was V = -1.08754 x (RCAS1 score) - 0.83174 x (TTF1 score) + 0.55204 x (cMET score) + 5.46972, and V = 0 served as a cut-off point. The correctness for evaluating a patient's 5-year survival by a discriminant analysis was 87.1%.

CONCLUSIONS

A discriminant analysis is thus considered to be a useful statistical method for analyzing the protein expression profiles obtained by combined TMA and immunohistochemical techniques using archival NSCLC tissues. However, the sample size and selection of the marker protein depending on the histology greatly influence the results of a NSCLC study.

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.

Proteasome inhibitors in lung cancer

Proteasome inhibition is a novel therapeutic approach that is being investigated in non-small cell and small cell lung cancer (NSCLC and SCLC). Proteasome inhibition affects a range of intracellular signals and disrupts the levels of numerous proteins, causing apoptosis via multiple pathways. Importantly, malignant cells are more sensitive to proteasome inhibition than normal cells. A number of proteasome inhibitors have demonstrated activity in preclinical studies, both as single agents and in combination with conventional and novel antineoplastic agents. However, only bortezomib, a dipeptide boronic acid analog, has been investigated in lung cancer clinical trials, in which it has shown activity as a single agent and in combination regimens. Numerous preclinical and clinical studies are ongoing in both NSCLC and SCLC. Proteasome inhibition could potentially play a significant role in the future management of these conditions.

Validation of molecular and immunological factors with predictive importance in lung cancer

Histological classification and staging are cornerstones of diagnosis in lung cancer. Treatment options have been enriched in the last few years by the development of a number of new drugs, and therapy is now increasingly being carried out within multimodal concepts and at earlier stages. Still, outcome of the disease is far from satisfactory and progress in clinical and preclinical research is time-consuming. With the whole variety of potent new therapeutic compounds including classical cytostatics and biological factors at hand, many now believe that a clear improvement of treatment results will be derived from a better understanding of the biology of these tumours and a resulting improvement of diagnosis. Biological factors reflecting the underlying tumour biology and aspects of clinically important pathomechanisms may not only better predict outcome of the disease but also of its treatment, serving as surrogate markers for a more appropriate general intensification of therapy and ideally for specific "targeted" interventions. This article describes the different insights in the biology of these tumours in relation with the representing surrogate markers, and opens routes to possible diagnostic and therapeutic consequences.

Expression of p27 in residual rectal cancer after preoperative chemoradiation predicts long-term outcome

BACKGROUND

Compared with surgery alone, preoperative radiotherapy and 5-fluorouracil-based chemotherapy (combined-modality therapy; CMT) improves outcomes in patients with locally advanced rectal cancer. Although numerous studies have focused on identifying molecular markers of prognosis in the primary rectal cancer before CMT, our aim was to identify markers of prognosis in residual rectal cancer after preoperative CMT.

METHODS

Sixty-seven patients with locally advanced (T3-4 and/or N1) rectal cancer were treated with preoperative radiotherapy (median, 5040 cGy) with or without 5-fluorouracil-based chemotherapy. Residual tumor in the resected specimen, available for 52 patients, was analyzed for tumor-node-metastasis stage, lymphovascular and/or perineural invasion, and immunohistochemical expression of p27, p21, p53, Ki-67, retinoblastoma gene, cyclin D1, and bcl-2. Recurrence-free survival (RFS) was determined by the Kaplan-Meier method and compared by the log-rank test.

RESULTS

With a median follow-up of 69 months, the overall 5-year RFS was 74%. RFS was significantly worse for patients with positive p27 expression (P = .005), T3-4 tumors (P = .02), and positive lymph nodes (P = .04) in the irradiated specimen. On multivariate analysis, positive p27 expression remained an independent negative prognostic factor for RFS (P = .04). None of the other proteins was significantly associated with RFS.

CONCLUSIONS

Our results indicate that positive p27 expression in rectal cancer after preoperative chemoradiation is an independent negative predictor of RFS. Expression of p27 in the residual rectal cancer may therefore identify patients with disease likely to be refractory to standard therapy and for whom investigational approaches should be strongly considered.

[Prognostic indicators in stage I non-small cell lung cancer]

INTRODUCTION

Determinating the prognosis of patients with stage I non-small cell lung cancer (NSCLC) is a challenge. Since up to 30% of patients who have undergone surgical resection experience recurrence, generally in distant organs, it is reasonable to postulate that neo-adjuvant or adjuvant treatments might be useful. Better knowledge of prognostic factors could perhaps define which patient populations should be targeted with such treatments.

STATE OF THE ART

Numerous potential prognostic factors, relating to the disease (TNM classification, histology, tumor size, blood vessels invasion, micro-metastasis, serum or molecular markers), the patient (gender, age, co-morbidity) as well as the treatment (delay, resection, lymph node dissection, neo-adjuvant and adjuvant treatments), are discussed.

PERSPECTIVES

These prognostic factors should be integrated into the design of future clinical trials of chemotherapy and/or radiotherapy attempting to evaluate the effectiveness of various combinations of neo-adjuvant or adjuvant therapies.

CONCLUSIONS

These factors may offer the opportunity to clinically and biologically characterize the different subgroups of patients, leading to a more rational, and perhaps individualized, choice of therapy.

Proteasome inhibition with PS-341 (bortezomib) in lung cancer therapy

PS-341 (bortezomib) represents a new class of therapeutics that targets the ubiquitin-proteasome pathway. It has broad-spectrum single-agent anticancer activity and can potentiate chemotherapy and radiation in preclinical models. Early phase clinical studies have shown tolerability and activity in multiple myeloma, lymphoma, prostate cancer, and lung cancers. By its mechanism of inhibiting protein degradation, PS-341 targets a wide range of pathways relevant to tumor progression and therapy resistance and can directly modulate expression of cyclins, p27(Kip1), p53, nuclear factor-kappaB, Bcl-2, and Bax. PS-341 is currently in phase I/II clinical development in both non-small cell lung cancer and small cell lung cancer. This article will review the preclinical and clinical experience with PS-341 as it relates to lung cancer.