Association of PTEN Gene SNPs rs2299939 With PFS in Patients With Small Cell Lung Cancer Treated With Early Radiotherapy

A novel PTEN mutant caused by polymorphism in cis-regulatory elements is involved in chemosensitivity in breast cancer

Phosphatase and tensin homolog (PTEN) is one of the most important tumor suppressor genes. Although studies have shown the association between cancer and genetic polymorphisms of PTEN, the underlying molecular mechanisms of breast cancer (BC) chemosensitivity that results from PTEN polymorphism is still unclear. This study aims to investigate potential links between PTEN polymorphisms in cis-regulatory elements and BC chemosensitivity in the Chinese population. A total of 172 BC patients who received neoadjuvant chemotherapy were included in the study, including 104 chemosensitive cases and 68 chemoresistant cases. The results showed a significant association between the rs786204926 polymorphism and BC chemosensitivity. Logistic multivariate regression analysis showed that age, lymph node metastasis, and the rs786204926 genotype were risk factors for BC chemoresistance. The G allele of rs786204926 is more prone to increasing the risk of chemosensitivity in BC. Additionally, analysis using Alamut Visual showed a preference of the G allele of rs786204926 to produce a novel PTEN mutant with an insertion of 18 bases from intron 4. While the transcriptional level of PTEN remained similar in chemosensitivity and chemoresistant samples, its protein level changed significantly. Interestingly, there were significant differences in both transcription and protein levels of the novel PTEN mutant between the two groups. Furthermore, we found that the mutant was more susceptible to dephosphorylation compared with wildtype PTEN, leading to chemosensitivity through the PI3K-AKT signaling pathway. These findings indicate that novel PTEN mutants caused by polymorphisms in cis-regulatory elements may be involved in BC chemosensitivity.

A novel evodiamine amino derivative as a PI3K/AKT signaling pathway modulator that induces apoptosis in small cell lung cancer cells

Evodiamine (EVO) was derivatized to a C10-amino derivative (EVA) using a two-step method suitable for industrializing production. This method has advantages such as a short reaction time, high yield, few byproducts and simple purification. The AUC and C_max values of EVA were 7.02- and 4.62-fold, while the T_max and Cl values were one-half and one-eighth that of EVO, respectively. EVA markedly improved the bioavailability, which might be ascribed to the serum albumin deposit effect. EVA was bound to albumin in the same hydrophobic pocket as EVO, but one more hydrogen bond was formed between Asp323 and the amino group at the C10 position. The amino derivative of natural alkaloids showed a substantial increase in antitumor activity on small cell lung cancer (SCLC) cells. The role of the PI3K/AKT signaling pathway in alkaloid/derivative-induced apoptosis in tumor cells was thoroughly described. p-AKT, its downstream effectors Bcl-2, Bax, caspase-3 and its upstream regulator PTEN were regulated by EVA. The interaction between EVO/EVA and the upstream protein PI3K p110 was first investigated with molecular docking. The apoptosis induced by EVA was abrogated after the PI3K/AKT signaling pathway was reactivated by IGF-1. The interaction between EVO/EVA and P-gp was also first studied using docking method. Their binding forces were weak. But EVA might reduce much expression of P-gp than EVO, and ultimately led to reduction of EVA efflux. Our study provides novel insights into a feasible and productive amino derivative of natural alkaloids for SCLC therapy.

Influence of VEGFR2 gene polymorphism on the clinical outcomes of apatinib for patients with chemotherapy-refractory extensive-stage SCLC: a real-world retrospective study

PURPOSE

Great individual differences were observed regarding the efficacy of apatinib clinically. The aim of present study was to investigate the influence of vascular endothelial growth factor receptor2 (VEGFR2) gene polymorphism on the clinical outcomes of apatinib for patients with chemotherapy-refractory extensive-stage small cell lung cancer (ES-SCLC).

METHODS

A total of 128 patients with chemotherapy-refractory ES-SCLC who were treated with apatinib at an initial dosage of 250 or 500 mg were included in this study. The change of target lesions was assessed. Overall response rate (ORR) was evaluated. Prognosis was carried out and safety profile was documented. Additionally, peripheral blood and biopsy cancer tissue specimens of the patients with SCLC were collected for the analysis of polymorphism and VEGFR2 gene mRNA expression, respectively. The association between genotype status and baseline characteristics was performed. Univariate analysis of genotype status and prognosis was carried out using Kaplan-Meier survival analysis and multivariate analysis were adjusted by Cox regression analysis.

RESULTS

Efficacy of apatinib included partial response (PR) in 15 patients, stable disease (SD) in 86 patients, progressive disease (PD) in 27 patients. Therefore, ORR of the 128 patients with ES-SCLC was 11.7%, and disease control rate (DCR) was 78.9%. Prognosis suggested that the median progression-free survival (PFS) and overall survival (OS) of the 128 patients with ES-SCLC was 4.2 months and 8.2 months, respectively. The polymorphism analysis focusing on VEGFR2 gene indicated that one single nucleotide polymorphism 889C>T was of clinical significance. Prevalence of 889C>T among the 128 patients with SCLC were as follows: CC genotype 87 cases (68.0%), CT genotype 38 cases (29.7%) and TT genotype 3 cases (2.3%), the minor allele frequency of 889C>T was 0.17, which was in accordance with Hardy-Weinberg Equilibrium (P = 0.628). Patients with CT and TT genotypes were merged in the subsequent analysis. Prognosis analysis exhibited that the median PFS of patients with CT/TT genotype and CC genotype was 3.3 and 5.0 months, respectively (P = 0.02). Furthermore, the median OS of patients was 5.5 and 9.0 months, respectively (P = 0.008). Additionally, multivariate Cox regression analysis of OS demonstrated that CT/TT genotype was an independent factor for OS [Hazard ratio (HR) = 0.64, P = 0.019]. However, the safety profile according to genotype status of 889C>T failed to show significant difference. Interestingly, mRNA expression analysis suggested that the mRNA expression of VEGFR2 in cancer tissues were significantly different according to CC and CT/TT genotypes (P < 0.001).

CONCLUSION

The administration with apatinib for patients with chemotherapy-refractory ES-SCLC was of potential clinical significance. The clinical outcomes of patients with ES-SCLC who were treated with apatinib could be impacted by VEGFR2 889C>T polymorphism through mediating the VEGFR2 mRNA expression.