[Tumor growth inhibition of paclitaxel-octreotide conjugates on human non small cell lung cancer: experiment with mice].

OBJECTIVE: To evaluate the antitumor effects of the conjugates synthesized by coupling cytotoxic paclitaxel (PTX) to somatostatin analog octreotide (OCT) on human non small cell lung cancer (NSCLC). METHODS: Two cytotoxic somatostatin analog, PTX-OCT and 2PTX-OCT, were developed in which PTX was linked to octreotide. Forty-five BALB/c nu/nu nude mice were injected with human NSCLC cells of the line A549 into the right armpit. The nude mice that were xenografted were randomly divided into 8 groups. (1) control group (n = 6), (2) PTX-OCT group (n = 5), injected intravenously with PTC-OCT 150 nmol/kg on days 1, 7, and 21, (3) 2PTX-OCT group (n = 6), injected intravenously with PTC-OCT 150 nmol/kg, (4) OP group (n = 6), injected with mixture of PTX and OCT 150 nmol/kg, (5) OCT group (n = 5) injected with OCT 150 nmol/kg (6) PTX group (n = 6), injected with PTX 150 nmol/kg, (7) 2PTX group, injected with PTX 300 nmol/kg, and (8) 2(PTX-OCT) injected with PTX-OCT 300 nmol/kg, The tumor volume and body weight (BW) were observed regularly. The tumor volume doubling time was calculated. White blood cells were counted by collecting peripheral blood sample. By the end of experiment the mice were killed with the tumors taken out. The expression of mRNA of subtypes1-5 of human somatostatin receptor (SSTR1-SSTR5) were investigated using RT-PCR. Histological apoptosis was detected by DNA ladder. Immunohistochemistry was used to examine the SSTR2 and SSTR5 expression and tumor microvessel density (MVD). RESULTS: The tumor volumes of 2PTX-OCT and 2(2PTX-OCT) groups were significantly smaller than those of other groups (all P < 0.01). The tumor doubling times of the 2PTX-OCT and 2 (2PTX-OCT) groups were significantly longer than those of the other groups too (all P < 0.01). The MVD levels of the 2PTX-OCT and 2 (2PTX-OCT) groups were significant lower than those of the other groups (all P < 0.01). The toxicity of the PTX group was more obvious. The WBC count levels of the PTX and 2PTX groups were significantly lower than those of the other groups (all P < 0.05). mRNA expression could be found for SSTR1, 2, 4, and 5 in the A549 xenografts. Immunohistochemistry showed that SSTR2 was mainly found in the tumor cell membrane, and SSTR5 was found in the tumor cell membrane and cytoplasm. More histological apoptosis bands were shown by DNA ladder method in the 2PTX-OCT and 2 (PTX-OCT) groups. CONCLUSION: The targeting conjugate 2PTX-OCT inhibits the proliferation of tumor cells, reduces microvessel, and decreases the toxicity in comparison with the cytotoxic radical PTX.

Loss of ß-arrestin-2 and Activation of CXCR2 Correlate with Lymph Node Metastasis in Non-small Cell Lung Cancer.

Background : Although ß-arrestin-2 (ß-arr2) and CXCR2 have been shown to affect various malignant tumors, their exact roles in lung cancer remain unclear. We investigated expression of ß-arr2 and CXCR2 in patients with non-small cell lung cancer (NSCLC) and their correlation with lymph node metastasis and prognosis. Methods : We reviewed medical records of 136 patients with NSCLC who underwent surgical resection, and assessed their specimens immunohistochemically for expression of ß-arr2 and CXCR2 in primary tumors and metastatic lymph nodes (MLNs), respectively. Results: High ß-arr2 expression was seen in 63 specimens (46.3%), and was significantly associated with male patients (P=0.011), squamous cell carcinoma (P=0.003), and lymph node metastasis (P<0.001). High CXCR2 expression was seen in 62 specimens (45.6%), and was significantly correlated only with lymph node metastasis (P<0.001). Expression of ß-arr2 was significantly lower at MLNs than at primary lesions (Z=-2.315; P=0.021; Wilcoxon signed-rank), whereas CXCR2 expression was significantly higher in MLNs than in primary lesions (Z=-3.712; P<0.001; Wilcoxon signed-rank). No relationship was seen between ß-arr2 and CXCR2 expression in primary lesions (r=-0.065, P=0.548; Spearman rank coefficient), but they were inversely related in MLNs (r=-0.263, P=0.012). Kaplan-Meier survival curve was shown that low ß-arr2 and high CXCR2 expressions was associated with poor survival (log-rank: χ2=5.926, P=0.015). Conclusions : ß-arr2 may promote lymph node metastasis in NSCLC by modulating CXCR2 activation.

Predictive and Prognostic Biomarkers for Patients Treated with Anti-EGFR Agents in Lung Cancer: A Systemic Review and Meta-Analysis.

BACKGROUND: Several studies have investigated predictive and prognostic biomarkers for patients treated with anti-epidermal growth factor receptor (EGFR) agents in lung cancer. However, the conclusion is controversial. MATERIALS AND METHODS: A meta-analysis was conducted to evaluate the associations of mutant K-ras, PIK3CA and PTEN deficiency with the efficacy of anti-EGFR agents in lung cancer. The primary endpoint was objective response rate (ORR). The secondary endpoints were overall survival (OS) and progression-free survival (PFS). RESULTS: A total of 61 studies were included in the final meta-analysis. The result showed that K-ras mutation was a good predictor for ORR (RR=0.42, 95%CI, 0.33-0.55, p=0.000) and an effective prognostic marker for OS (HR=1.37, 95%CI, 1.15-1.65, p=0.001) and PFS (HR=1.33, 95%CI, 1.05-1.69, p=0.019). However, PTEN deficiency or PIK3CA mutation did not show any significance predictive value for ORR (PTEN, RR=0.82, 95%CI, 0.56-1.19, p=0.286; PIK3CA, RR=1.08, 95%CI, 0.17-6.66, P=0.938). And PTEN deficiency or expression of PIK3CA did not show significance prognostic value for OS (PTEN, HR=0.88, 95%CI, 0.31-2.46,P=0.805; PIK3CA, HR=0.79, 95%CI: 0.23-2.68, P=0.706). CONCLUSIONS: Our meta-analysis showed that K-ras mutation may be an effective predictor in lung cancer patients treated with anti-EGFR agents. Whereas, the predictive and prognostic value of PTEN deficiency and PIK3CA mutation need to be further investigated.

MicroRNA-34b functions as a tumor suppressor and acts as a nodal point in the feedback loop with Met.

MicroRNAs (miRNAs), as a class of naturally occurring small non-coding RNAs, play profound and pervasive roles in cancer initiation and progression. Extensive decrease in miRNA levels are frequently observed in human cancers, indicating that miRNAs may function intrinsically in tumor suppression. However, the underlying mechanisms of miRNA interactions with cellular pathways are still unclear. The expression of miR-34b in non-small cell lung cancer (NSCLC) tissues was detected using quantitative real-time PCR. The relations between miR-34b expression levels and pathological stage or lymph node metastasis were assessed using the Spearman correlation test. For in vitro studies, lung cancer cells were transfected with double stranded synthetic miRNA mimics (syn-hsa-miR-34b miScript miRNA) and scrambled controls. Immunohistochemistry was used to validate the related downstream proteins of miR-34b. The expression of miR-34b was lower in NSCLC tissues compared to that in pericarcinous tissues of lung cancer. Additionally, the Spearman correlation test showed that lower miR-34b expression was correlated with higher lymph node metastasis. In vitro gain-of-function experiments indicated that miR-34b suppressed cell proliferation by inducing cell apoptosis. IHC results showed association between lower miR-34b and overexpression of phospho-Met, p53 (phospho S392) and Mdm2. Consistent with the opposing correlation between the expression of miR-34b and lymph node metastasis in NSCLC, miR-34b may play an important role in NSCLC progression. Furthermore, miR-34b downregulates Met, with subsequent changes of downstream p53 (phospho S392) and Mdm2, and inversely p53 upregulates miR-34b in a feedback loop, which provides new insights into the roles of miR-34 family members in the regulation of signaling pathways of NSCLC.

Loss of DBC2 expression is an early and progressive event in the development of lung adenocarcinoma.

PURPOSE: DBC2 (Deleted in Breast Cancer 2) has been indicated to be a tumor suppressor gene in many cancers including lung adenocarcinoma recently. In this study, we aimed to explore the expression status of DBC2 in different subtypes of lung adenocarcinoma (from pre-invasive to invasive lesions), and to determine if downregulation becomes more marked with pathological progression. METHODS: We collected 172 tissue samples from different subtypes of lung adenocarcinoma and investigated the frequency of DBC2 loss by immunohistochemistry. RESULTS: Our results indicated that DBC2 downregulation is a relatively frequent event in lung adenocarcinoma. Moreover, as the adenocarcinoma subtype turns to be more invasive, more downregulation occurred. CONCLUSION: We conclude that loss of DBC2 expression is an early and progressive event in the pathogenesis of lung adenocarcinoma. Positive DBC2 immunohistochemistry may become an indicator for early stage disease and better prognosis of lung adenocarcinomas.