Rapalogs induce non-apoptotic,autophagy-dependent cell death in HPV-negative TP53 mutant head and neck squamous cell carcinoma

TP53 is the most frequently mutated gene in head and neck squamous cell carcinoma (HNSCC). Patients with HPV-negative TP53 mutant HNSCC have the worst prognosis, necessitating additional agents for treatment. Since mutant p53 causes sustained activation of the PI3K/AKT/mTOR signaling pathway, we investigated the effect of rapalogs RAD001 and CCI-779 on HPV-negative mutTP53 HNSCC cell lines and xenografts. Rapalogs significantly reduced cell viability and colony formation. Interestingly, rapalogs-induced autophagy with no effect on apoptosis. Pretreatment with autophagy inhibitors, 3-methyladenine (3-MA) and ULK-101 rescued the cell viability by inhibiting rapalog-induced autophagy, suggesting that both RAD001 and CCI-779 induce non-apoptotic autophagy-dependent cell death (ADCD). Moreover, rapalogs upregulated the levels of ULK1 and pULK1 S555 with concomitant downregulation of the mTORC1 pathway. However, pretreatment of cells with rapalogs prevented the ULK-101-mediated inhibition of ULK1 to sustained autophagy, suggesting that rapalogs induce ADCD through the activation of ULK1. To further translate our in vitro studies, we investigated the effect of RAD001 in HPV-negative mutTP53 (HN31 and FaDu) tumor cell xenograft model in nude mice. Mice treated with RAD001 exhibited a significant tumor volume reduction without induction of apoptosis, and with a concomitant increase in autophagy. Further, treatment with RAD001 was associated with a considerable increase in pULK1 S555 and ULK1 levels through the inhibition of mTORC1. 3-MA reversed the effect of RAD001 on FaDu tumor growth suggesting that RAD001 promotes ACDC in HPV-negative mutTP53 xenograft. This is the first report demonstrating that rapalogs promote non-apoptotic ADCD in HPV-negative mutTP53 HNSCC via the ULK1 pathway. Further studies are required to establish the promising role of rapalogs in preventing the regrowth of HPV-negative mutTP53 HNSCC.     

In silico repurposing the Rac1 inhibitor NSC23766 for treating PTTG1-high expressing clear cell renal carcinoma

The pituitary tumor-transforming gene 1 (PTTG1), also known as Securin, is considered an oncogene. This study aimed to investigate the role of PTTG1 in clear cell renal cell carcinoma (ccRCC) using in silico bioinformatics approaches. A pan-cancer analysis using The Cancer Genome Atlas (TCGA) data indicated that among all cancer types copy number amplification of PTTG1 gene was most frequently found in ccRCC. However, amplification of PTTG1 gene copy number did not correlate with the increase of mRNA level in ccRCC, and did not predict the patients' overall survival. Instead, ccRCC was correlated with overexpression of PTTG1 mRNA, and its expression level was stage-dependent increased in cancer patients. An outlier analysis using the Oncomine database suggested that PTTG1 mRNA expression served as a good biomarker for ccRCC. Pathway analysis for upregulated genes enriched in PTTG1-high expressing ccRCC patients found that PTTG1 overexpression was associated with mitotic defects. Mining drug sensitivity data using the Cancer Therapeutics Response Portal (CTRP) discovered that PTTG1-high expressing ccRCC cell lines were susceptible to a Rac1 (Ras-related C3 botulinum toxin substrate 1) inhibitor NSC23766. Therefore, this study provides an in silico insight into the role of PTTG1 in ccRCC, and repurposes the Rac1 inhibitor NSC23766 for treating PTTG1-high expressing ccRCC.     

骨髓激酶X对宫颈癌细胞增殖的影响及可能的作用机制

目的 探讨骨髓激酶X（bone marrow X-linked kinase，BMX）对人宫颈癌细胞增殖的影响及其可能的作用。方法 收集2013—2017年本院34例正常宫颈、25例原位宫颈癌和52例浸润性宫颈癌的临床标本，采用免疫组织化学方法检测不同标本中BMX的表达。转染BMX-TALEN重组质粒构建敲低BMX表达宫颈癌细胞HeLa-BMX^+/-。宫颈癌细胞HeLa-BMX^+/-和HeLa-野生型细胞分别培养于含抑制剂MK-2206和雷帕霉素完全培养基中，并以培养于含有DMSO培养基的细胞为对照组。采用MTT分析测定细胞活力，Western blot检测BMX、Akt、p-Akt、mTOR和p-mTOR表达。结果 免疫组织化学法检测结果显示，正常宫颈组织、原位宫颈癌组织及浸润性宫颈癌组织BMX阳性率差异有统计学意义（26.5% vs 68.0% vs 88.5%，χ²=34.804，P<0.001），两两比较差异亦有统计学意义（P<0.05）。成功构建低表达BMX宫颈癌细胞HeLa-BMX^+/-。Western blot结果显示，BMX和p-Akt在HeLa-BMX^+/-细胞中的表达低于HeLa-野生型细胞（t=6.282，8.117，P<0.001），总Akt表达水平差异无统计学意义（t=2.035，P=0.126）。与对照组比较，经MK-2206和雷帕霉素处理的HeLa-野生型及BMX+/-细胞中p-Akt和p-mTOR的表达均明显受抑制。结论 BMX可能通过PI3K/Akt/mTOR信号通路促进宫颈癌细胞增殖。     

A Phase II Open Label Study of Everolimus in Combination With Endocrine Therapy in Resistant Hormone Receptor-Positive HER2-Negative Advanced Breast Cancer

BackgroundTherapies targeting estrogen receptor signaling are standard for patients with hormone receptor (HR)-positive (HR⁺) metastatic breast cancer (MBC). Dysregulation of the phosphoinositol 3-kinase (PI3K)/protein kinase B (AKT)/mammalian target of rapamycin (mTOR) pathway is associated with treatment resistance. Addition of the mTOR inhibitor, everolimus, to exemestane doubled progression-free survival (PFS) in HR⁺/HER2⁻ MBC patients whose disease had previously progressed during endocrine therapy. In this phase II study, we used everolimus in addition to the most recent endocrine therapy during which a patient's disease progressed, in an attempt to restore and extend the benefit of the antiestrogen therapy in patients with HR⁺/HER2⁻ MBC.Patients and MethodsPatients with HR⁺ MBC who progressed on antiestrogen therapy received everolimus (10 mg orally daily) in combination with the antiestrogen therapy most recently administered. Treatment was administered in 4-week cycles and continued until disease progression or unacceptable toxicity. Blood and archival tumor specimens were collected for VeriStrat (Biodesix, Inc) and Foundation One (Foundation Medicine) assays, respectively. Accrual of 42 evaluable patients allowed detection of improvement in median PFS from 2.8 months (expected with hormonal treatment alone) to 5 months (power 80%, α = 5%).ResultsForty-seven patients were enrolled and treated. After a median follow-up of 22.2 months, median PFS was 6.6 months. Secondary efficacy end points included: overall response rate, 6%; clinical benefit rate, 40%; and median overall survival, 21.1 months. No unexpected toxicity was observed. Efficacy could not be correlated with PI3K/AKT/mTOR alterations or VeriStrat (Biodesix, Inc) prognostic signatures.ConclusionAfter progression during antiestrogen therapy, the addition of everolimus, without changing the hormonal therapy, resulted in a median PFS of 6.6 months, suggesting efficacy in patients with HR⁺/HER2⁻ MBC.     

新加归肾丸通过调节mTOR信号通路促进体外培养大鼠卵巢颗粒细胞增殖

目的:观察补肾活血中药复方新加归肾丸对体外培养大鼠卵巢颗粒细胞增殖的影响。方法:体外培养大鼠卵巢颗粒细胞,分为空白组,模型组,中药低、中、高剂量组共五组,空白组用1%胎牛血清培养基培养,其余四组滴加雷帕霉素,20 min后中药各组加入不同浓度的中药水提醇沉液。分别在培养24、48、72 h后采用流式细胞仪检测细胞周期各时相的变化,并计算细胞增殖指数(PI); 免疫印迹法检测磷酸化-哺乳动物雷帕霉素靶蛋白(p-mTOR)、细胞周期蛋白D₂(Cyclin D₂)的表达水平。结果:用药24、48、72 h 这3个时段,中药各组S期细胞比率、PI均高于模型组(P<0.05),其中中药中剂量组最为明显(P<0.05)。用药24、48、72 h这3个时段,中药各个剂量组p-mTOR、Cyclin D₂表达水平均高于模型组(P<0.05)。中药各个剂量中以中药中剂量组效果最明显(P<0.05)。结论:补肾活血中药复方新加归肾丸能通过激活mTOR信号通路活性,上调Cyclin D₂蛋白表达,促使颗粒细胞由G₁期向S期转化,加速卵巢颗粒细胞周期进程,促进颗粒细胞增殖来实现改善卵泡发育。