Curcumin inhibits pancreatic cancer cell proliferation by regulating Beclin1 expression and inhibiting the hypoxia-inducible factor-1α-mediated glycolytic pathway

BackgroundPancreatic cancer has a high degree of malignancy and high mortality. Understanding its biological status can provide more therapeutic targets for the future. The present study was to investigate whether curcumin can inhibit pancreatic cancer cell proliferation by regulating Beclin1 expression and inhibiting the hypoxia-inducible factor-1α (HIF-1α)-mediated glycolytic pathway.MethodsTwo pancreatic cancer cell lines, PANC-1 and SW1990, were treated with different concentrations of curcumin (0, 20, 40, and 60 µM). Cell viability was detected using the Cell Counting Kit-8 (CCK-8) assay and flow cytometry was performed to determine the apoptosis rate and cell cycle arrest of the pancreatic cancer cells. PANC-1 and SW1990 cells were treated with different concentrations of curcumin under hypoxic conditions for 48 hours to detect the relative expression of the Beclin1 protein. The co-immunoprecipitation (co-IP) method was used to determine whether curcumin could inhibit the interaction between Beclin1 and HIF-1α.ResultsThe proliferation inhibition rates of PANC-1 cells after exposure to 0, 20, 40, and 60 µM curcumin were 0%, 31.6%, 47.2%, and 63.9%, respectively, and that of SW1990 cells were 0%, 18.8%, 46.3%, and 63.5% respectively. Western blot analyses showed decreased expression of Beclin1 in cells treated with curcumin. The expression of Beclin1 in the nucleus and cytoplasm decreased with increasing concentrations of curcumin. Co-IP results demonstrated that curcumin inhibited the interaction between Beclin1 and HIF-1α. Treatment with the higher doses of curcumin (40 and 60 µM) significantly decreased the protein expression levels of HIF-1α. In addition, the expression levels of Kidney-Specific Cadherin (HSP70, HSP90, and von Hippel-Lindau protein (pVHL) were significantly decreased in pancreatic cancer cells while the expression of prolyl hydroxylase (PHD) and receptor of activated protein kinase C (RACK1) increased significantly. Furthermore, curcumin reduced cellular adenosine triphosphate (ATP) production in a dose-dependent manner. Compared with control pancreatic cancer cells, the expression levels of GLUT1, HK2, LDHA, and PDK1 gradually decreased with increasing curcumin concentrations.ConclusionsCurcumin can inhibit the expression of Beclin1 and HIF-1α in pancreatic cancer cells under anoxic conditions, thereby affecting the glycolysis pathway and inhibiting cell proliferation.     

IL-32α suppresses colorectal cancer development via TNFR1-mediated death signaling

Inflammation is associated with cancer-prone microenvironment, leading to cancer. IL-32 is expressed in chronic inflammation-linked human cancers. To investigate IL-32α in inflammation-linked colorectal carcinogenesis, we generated a strain of mice, expressing IL-32 (IL-32α-Tg). In IL-32α-Tg mice, azoxymethane (AOM)-induced colon cancer incidence was decreased, whereas expression of TNFR1 and TNFR1-medicated apoptosis was increased. Also, IL-32α increased ROS production to induce prolonged JNK activation. In colon cancer patients, IL-32α and TNFR1 were increased. These findings indicate that IL-32α suppressed colon cancer development by promoting the death signaling of TNFR1.     

Prospective neoadjuvant analysis of PET imaging and mechanisms of resistance to Trastuzumab shows role of HIF1 and autophagy

Background:

Although Trastuzumab has improved survival of HER2+ breast cancer patients, resistance to the agent pre-exists or develops through the course of therapy. Here we show that a specific metabolism and autophagy-related cancer cell phenotype relates to resistance of HER2+ breast cancer to Trastuzumab and chemotherapy.

Methods:

Twenty-eight patients with locally advanced primary breast cancer were prospectively scheduled to received one cycle of Trastuzumab followed by a new biopsy on day 21, followed by taxol/Trastuzumab chemotherapy for four cycles before surgery. FDG PET/CT scan was used to monitor tumour response. Tissue samples were immunohistochemically analysed for metabolism and autophagy markers.

Results:

In pre-Trastuzumab biopsies, the LC3A+/HER2+ cell population was correlated with HIF1α expression (P=0.01), while GLUT1 and LC3B expression were correlated with Ki67 proliferation index (P=0.01 and P=0.01, respectively). FDG PET tumour dimensions before therapy were correlated with LC3B expression (P=0.005). Administration of Trastuzumab significantly reduced clinical and PET-detected tumour dimensions (P<0.01). An inverse association of tumour response with the percentage of cells expressing HIF1α at baseline was documented (P=0.01). Administration of Trastuzumab resulted in a decrease of the proliferation index (P=0.004), GLUT1 (P=0.04) and HER2 (P=0.01) expression. In contrast, the percentage of LC3A+/HER2+ cells was increased (P=0.01). High baseline HIF1α expression was the only parameter associated with poorer pathological response to preoperative chemotherapy (P=0.001).

Conclusions:

As the HER2+/LC3A+ phenotype, which often overexpresses HIF1α, is a major subpopulation increasing after therapy with Trastuzumab, LC3A- and HIF1α-targeting therapies should be investigated for the augmentation of anti-HER2 therapy efficacy.     

Tumor‐associated macrophage‐derived transforming growth factor‐β promotes colorectal cancer progression through HIF1‐TRIB3 signaling

Tumor‐associated macrophages (TAMs), one of the most common cell components in the tumor microenvironment, have been reported as key contributors to cancer‐related inflammation and enhanced metastatic progression of tumors. To explore the underlying mechanism of TAM‐induced tumor progression, TAMs were isolated from colorectal cancer patients, and the functional interaction with colorectal cancer cells was analyzed. Our study found that coculture of TAMs contributed to a glycolytic state in colorectal cancer, which promoted the stem‐like phenotypes and invasion of tumor cells. TAMs produced the cytokine transforming growth factor‐β to support hypoxia‐inducible factor 1α (HIF1α) expression, thereby upregulating Tribbles pseudokinase 3 (TRIB3) in tumor cells. Elevated expression of TRIB3 resulted in activation of the β‐catenin/Wnt signaling pathway, which eventually enhanced the stem‐like phenotypes and cell invasion in colorectal cancer. Our findings provided evidence that TAMs promoted colorectal cancer progression in a HIF1α/TRIB3‐dependent manner, and blockade of HIF1α signals efficiently improved the outcome of chemotherapy, describing an innovative approach for colorectal cancer treatment.     

自噬基因Beclin1在卵巢癌中的研究进展

卵巢癌是女性生殖系统常见恶性肿瘤之一，以手术、铂类和紫杉烷类药物为主的治疗方案已被确立为卵巢癌治疗的标准，但其死亡率仍位居妇科肿瘤之首。自噬是一种高度保守的细胞代谢过程，参与细胞的病理、生理等过程。近年来研究发现自噬与肿瘤有重要而复杂的关系。Beclin1是自噬体形成过程中重要的靶点，具有抑制肿瘤生长的作用，但目前Beclin1与卵巢癌的关系尚不清楚。本文将从Beclin1与卵巢癌发生发展、治疗及耐药的关系这三个方面进行综述，以期为卵巢癌早期诊断及肿瘤的治疗提供新的思路。     

Expression of SAMHD1 and its mutation on prognosis of colon cancer

The expression of sterile α motif and histidine/aspartic acid domain-containing protein 1 (SAMHD1) and its mutation play a key role in the prognosis of colon cancer. The aim of the present study was to investigate the mechanism and the role of SAMHD1 in colon cancer. Microarray data from 187 patients with colon cancer and 45 adjacent normal tissue obtained from the Gene Expression Omnibus (GEO) were analyzed. A protein-protein interaction (PPI) network was constructed to identify key genes associated with colon cancer prognosis. Cox proportional hazard regression and survival analyses were performed to identify the potential for SAMHD1 to serve as a prognostic biomarker. Immunohistochemistry (IHC) and immunofluorescence (IF) were performed to assess the expression levels and distribution of SAMHD1 in tissues and cells. Western blotting (WB) and Cell Counting Kit-8 (CCK-8) assays were used to identify the proliferation and apoptotic effects of SAMHD1 on HT-29 (Cas9-SAMHD1) cell lines. A total of 6,905 consistently differentially expressed genes were identified in the GEO database. Through the PPI network, SAMHD1 was found to be associated with Kirsten rat sarcoma virus (KRAS). SAMHD1 expression was negatively associated with KRAS. Proportional hazards regression and survival analyses demonstrated that low expression of SAMHD1 was associated with increased patient mortality. IHC and IF results demonstrated that SAMHD1 expression in patients with colon cancer was decreased compared with controls (both P<0.05). CCK-8 and WB results showed that proliferation was significantly promoted, and the expression levels of apoptosis-related proteins were significantly inhibited in the D137N and D311A groups as a result of a mutation in the deoxynucleoside triphosphohydrolase (dNTPase) site (both P<0.05 vs. wild-type). Proliferation was inhibited and apoptosis-related protein expression levels were promoted in the wild-type (WT) and D137N groups following 20 µg/ml 5-fluorouracil (5-FU) treatment (both P<0.05). WB and CCK-8 results showed cell proliferation was promoted and cell apoptosis-related protein expression was inhibited in the D137N group following treatment with 20 µg/ml 5-FU (all P<0.05) compared with the WT group. In conclusion, SAMHD1 expression was low in colon cancer. The dNTPase function of SAMHD1 may inhibit colon cancer cell proliferation and may enhance apoptosis. In addition, first-line chemotherapy with 5-FU has a time-dependent effect, which may provide novel options for clinical treatment of colon cancer.     

Mitochondrial malic enzyme 2 promotes breast cancer metastasis via stabilizing HIF-1α under hypoxia

Objectiveα-ketoglutarate (α-KG) is the substrate to hydroxylate collagen and hypoxia-inducible factor-1α (HIF-1α), which are important for cancer metastasis. Previous studies have shown that the upregulation of collagen prolyl 4-hydroxylase in breast cancer cells stabilizes the expression of HIF-1α by depleting α-KG levels. We hypothesized that mitochondrial malic enzyme 2 (ME2) might also affect HIF-1α expression via modulating α-KG levels in breast cancer cells.MethodsWe evaluated ME2 protein expression in 100 breast cancer patients using immunohistochemistry and correlated with clinicopathological indicators. The effect of ME2 knockout on cancer metastasis was evaluated using an orthotopic breast cancer model. The effect of ME2 knockout or knockdown on the levels of α-KG and HIF-1α proteins in breast cancer cell lines was determined both in vitro and in vivo. ResultsME2 was found to be upregulated in the human breast cancerous tissues compared with the matched precancerous tissues (P<0.001). The elevated expression of ME2 was associated with a poor prognosis (P=0.019). ME2 upregulation was also related to lymph node metastasis (P=0.016), pathological staging (P=0.033), and vascular cancer embolus (P=0.014). Also, ME2 knockout significantly inhibited lung metastasisin vivo. In the tumors formed by ME2 knockout cells, the levels of α-KG were significantly increased and collagen hydroxylation level did not change significantly but HIF-1α protein expression was significantly decreased, compared to the control samples. In cell culture, cells with ME2 knockout or knockdown demonstrated significantly higher α-KG levels but significantly lower HIF-1α protein expression than control cells under hypoxia. Exogenous malate and α-KG exerted similar effect on HIF-1α in breast cancer cells to ME2 knockout or knockdown. Additionally, treatment with malate significantly decreased 4T1 breast cancer lung metastasis. ME2 expression was associated with HIF-1α levels in human breast cancer samples (P=0.008). ConclusionsOur results provide evidence that upregulation of ME2 is associated with a poor prognosis of breast cancer patients and propose a mechanistic understanding of a link between ME2 and breast cancer metastasis.     

大肠癌组织自噬相关蛋白Beclin1表达意义Meta分析

目的 大肠癌发病率逐年增加,其发病机制未完全明了.自噬在肿瘤的发生、发展中有重要作用,Beclin1(BECN 1)是哺乳动物参与自噬的特异性基因,本研究采用循证医学的方法分析大肠癌组织中Beclin1表达的临床意义,为Beclin1对大肠癌发生、发展的影响提供可靠的证据.方法 检索Cochrane library、PubMed、Web of Science、EMBASE、Springer link、中国知网、万方数据库和维普中文科技期刊数据库等至2016-04-01,收集发表的关于大肠癌组织中Beclin1在不同特征人群中表达的文献,筛选符合标准的文献.采用纽卡斯尔-渥太华量表(New castle-Ottawa Scale,NOS)对文献质量进行严格质控,应用RevMan 5.3软件进行数据处理.结果 最终纳入15篇文献,包括大肠癌患者1 733例.Meta分析结果显示,大肠癌组织中Beclin1阳性率明显高于大肠腺瘤组织(OR[2.48,95％CI为1.41～4.37,P＜0.05)及正常大肠组织(OR=8.33,95％CI为3.92～17.72,P＜0.05);腺瘤组织Beclin1阳性率明显高于正常大肠组织,OR=4.49,95％CI为2.29～8.80,P＜0.05;管状腺癌组织中Beclin1阳性率略高于除腺癌外其他类型癌组织,OR=0.1,95％CI为0.00～0.19,P=0.04.Beclin1表达与大肠癌患者的年龄、性别、临床分期、发病部位、肿瘤大小、病理类型、是否侵及浆膜及是否转移等无相关性,均P＞0.05.结论 Beclin1基因促进了大肠癌的形成与发展.     

P4HA1 regulates human colorectal cancer cells through HIF1α-mediated Wnt signaling

Colorectal cancer (CRC) is the third most commonly diagnosed malignancy that is associated with high levels of mortality. CRCs are often associated with an aberrant wingless-type mouse mammary tumor virus integration site family (Wnt) signaling pathway known to be responsible for tumorigenesis and cancer progression. Other factors that contribute to CRC pathology include hypoxia, extracellular matrix and cellular microenvironment. In the present study, modulation of Wnt, a common molecular progenitor for CRC-associated pathology was evaluated. CRC tissues and specific cell lines were found to exhibit increased expression levels of prolyl 4-hydroxylase subunit α1 (P4HA1). P4HA1 expression was found to stabilize hypoxia inducible factor-1α (HIF1α). The silencing of P4HA1 resulted in decreased cell proliferation, cell cycle arrest in the G₁ phase, decreased tumorsphere formation, decreased tumorsphere volume, increased susceptibility to 5-fluorouracil and increased caspase-3 activity. However, P4HA1 silencing resulted in the activation and thus proteasomal degradation of β-catenin, indicative of the abrogation of Wnt signaling pathway. Wnt is a critical signaling pathway and is activated in most CRCs. HIF1α is a poor prognostic marker in CRC. The present study provided preliminary evidence that HIF1α and the Wnt signaling pathway in CRC are modulated through P4HA1. P4HA1 may serve not just as a biomarker for CRC prognosis but may also be targeted for potential therapeutic intervention.     

Overexpression of Collagen Triple Helix Repeat Containing 1 (CTHRC1) is associated with tumour aggressiveness and poor prognosis in human non-small cell lung cancer

Collagen triple helix repeat-containing 1 (CTHRC1), a novel oncogene, was identified to be aberrantly overexpressed in several malignant tumors. However, the expression profile of CTHRC1 and its clinical significance in non-small cell lung cancer (NSCLC) remain unknown. In this study, we showed that CTHRC1 was evidently overexpressed in human NSCLC tissues and NSCLC cell lines at the protein and mRNA level. Ectopic up-regulation of CTHRC1 in cancer cells resulted in elevated invasive and proliferative abilities, which were attenuated by the specific CTHRC1 siRNA. The biological effect of CTHRC1 on metastasis and proliferation was mediated by the activation of the Wnt/β-catenin pathway. Furthermore, CTHRC1 immunoreactivity was evidently overexpressed in paraffin-embedded NSCLC tissues (212/292, 72.60%) in comparison to corresponding adjacent non-cancerous tissues (6/66, 9.09%) (p<0.001). Clinicopathologic analysis showed that CTHRC1 expression was significantly correlated with differentiation degree (p<0.001), clinical stage (p<0.001), T classification (p<0.001), lymph node metastasis (p=0.013) and distant metastasis (p<0.001). Kaplan-Meier analysis revealed that patients with high CTHRC1 expression had poorer overall survival rates than those with low CTHRC1 expression. Multivariate analysis indicated that CTHRC1 expression was an independent prognostic factor for the overall survival of NSCLC patients. Collectively, CTHRC1 plays important roles in NSCLC progression, and the evaluation of CTHRC1 expression could serve as a potential marker for metastasis progression and prognosis in NSCLC patients.     

Tumour-stroma interactions in colorectal cancer: converging on beta-catenin activation and cancer stemness

Sporadic cases of colorectal cancer are primarily initiated by gene mutations in members of the canonical Wnt pathway, ultimately resulting in beta-catenin stabilisation. Nevertheless, cells displaying nuclear beta-catenin accumulation are nonrandomly distributed throughout the tumour mass and preferentially localise along the invasive front where parenchymal cells are in direct contact with the stromal microenvironment. Here, we discuss the putative role played by stromal cell types in regulating beta-catenin intracellular accumulation in a paracrine fashion. As such, the tumour microenvironment is likely to maintain the cancer stem cell phenotype in a subset of cells, thus mediating invasion and metastasis.     

Expression of SDF-1 alpha and nuclear CXCR4 predicts lymph node metastasis in colorectal cancer

Although stromal cell-derived factor (SDF)-1 alpha and its receptor CXCR4 are experimentally suggested to be involved in tumorigenicity, the clinicopathological significance of their expression in human disease is not fully understood. We examined SDF-1 alpha and CXCR4 expression in colorectal cancers (CRCs) and their related lymph nodes (LNs), and investigated its relationship to clinicopathological features. Specimens of 60 primary CRCs and 27 related LNs were examined immunohistochemically for not only positivity but also immunostaining patterns for SDF-1 alpha and CXCR4. The relationships between clinicopathological features and SDF-1 alpha or CXCR4 expression were then analysed. Stromal cell-derived factor-1 alpha and CXCR4 expression were significantly associated with LN metastasis, tumour stage, and survival of CRC patients. Twenty-nine of 47 CXCR4-positive CRCs (61.7%) showed clear CXCR4 immunoreactivity in the nucleus and a weak signal in the cytoplasm (nuclear type), whereas others showed no nuclear immunoreactivity but a diffuse signal in the cytoplasm and at the plasma membrane (cytomembrane type). Colorectal cancer patients with nuclear CXCR4 expression showed significantly more frequent LN metastasis than did those with cytomembrane expression. Colorectal cancer patients with nuclear CXCR4 expression in the primary lesion frequently had cytomembrane CXCR4-positive tumours in their LNs. In conclusion, expression of SDF-1 alpha and nuclear CXCR4 predicts LN metastasis in CRCs.     

Cytoglobin is upregulated by tumour hypoxia and silenced by promoter hypermethylation in head and neck cancer

Background:

Cytoglobin (Cygb) was first described in 2002 as an intracellular globin of unknown function. We have previously shown the downregulation of cytoglobin as a key event in a familial cancer syndrome of the upper aerodigestive tract.

Methods:

Cytoglobin expression and promoter methylation were investigated in sporadic head and neck squamous cell carcinoma (HNSCC) using a cross-section of clinical samples. Additionally, the putative mechanisms of Cygb expression in cancer were explored by subjecting HNSCC cell lines to hypoxic culture conditions and 5-aza-2-deoxycitidine treatment.

Results:

In clinically derived HNSCC samples, CYGB mRNA expression showed a striking correlation with tumour hypoxia (measured by HIF1A mRNA expression P=0.013) and consistent associations with histopathological measures of tumour aggression. CYGB expression also showed a marked negative correlation with promoter methylation (P=0.018). In the HNSCC cell lines cultured under hypoxic conditions, a trend of increasing expression of both CYGB and HIF1A with progressive hypoxia was observed. Treatment with 5-aza-2-deoxycitidine dramatically increased CYGB expression in those cell lines with greater baseline promoter methylation.

Conclusion

We conclude that the CYGB gene is regulated by both promoter methylation and tumour hypoxia in HNSCC and that increased expression of this gene correlates with clincopathological measures of a tumour''s biological aggression.     

胃癌组织Beclin1表达与幽门螺杆菌感染的相关性

目的:探讨胃癌组织自噬相关蛋白Beclin1的表达和临床意义,及与幽门螺杆菌(HP)感染的相关性.方法:应用免疫组化法检测120例胃癌和配对正常胃组织中自噬相关蛋白Beclin1的表达;分析Beclin1的表达和临床病理学参数的关系;分析Beclin1的表达和无疾病进展生存(disease free survival,DFS)的相关性;应用碳14呼气试验检测胃癌患者幽门螺杆菌的感染,并分析Beclin1的表达和HP感染的相关性.结果:Beclin1在胃癌和正常胃组织的高表达率分别为59.2%(71/120)、36.7%(44/120),胃癌组织Beclin1的高表达率显著高于正常胃组织,差异有统计学意义(P=0.004).Beclin1的高表达与胃癌患者pTNM分期(P<0.001)和区域淋巴结转移(P<0.001)有显著负相关性.与Beclin1高表达的患者比较,Beclin1低表达患者的中位DFS显著缩短(21 vs 25个月,P=0.032).HP阳性胃癌组织的Beclin1高表达率显著高于HP阴性者(71.0%vs 43.1%,P=0.002);Spearmen相关性检验显示HP感染和Beclin1表达有显著相关性(γ=0.280,P=0.002);logistic回归分析显示HP感染对Beclin1表达有显著影响(P=0.009).结论:胃癌组织Beclin1表达水平增高;Beclin1高表达提示较好的预后;HP感染与Beclin1表达有显著相关性.     

TIM-4 promotes the growth of non-small-cell lung cancer in a RGD motif-dependent manner

Background:

T-cell immunoglobulin domain and mucin domain 4 (TIM-4) is exclusively expressed in antigen-presenting cells and involved in immune regulation. However, the role of TIM-4 expressed in tumour cells remains completely unknown.

Methods:

Immunohistochemistry staining was used to examine TIM-4 or Ki-67 expression in tumour tissues. Real-time PCR or RT-PCR was performed to detect TIM-4 mRNA expression. Lung cancer cell growth and proliferation were conducted by CCK-8 assay and EdU staining. Cell cycle progression was analysed by flow cytometry. The PCNA and cell cycle-related proteins were verified by western blot. Co-IP assay was used to identify the interaction of TIM-4 and integrin αvβ3. The efficacy of TIM-4 in vivo was evaluated using xenograft tumour model.

Results:

The expression of TIM-4 in non-small-cell lung cancer (NSCLC) tissues was significantly higher than that of the adjacent tissues. Enhanced TIM-4 expression was negatively correlated with histological differentiation of lung carcinoma and lifespan of patients. Overexpression of TIM-4 promoted lung cancer cell growth and proliferation, and upregulated the expression of PCNA, cyclin A, cyclin B1 and cyclin D1, accompanied by accumulation of lung cancer cells in S phase. Interestingly, Arg-Gly-Asp (RGD) motif mutation abolished the effect of TIM-4 on lung cancer cells, which was further verified by tumour xenografts in mice. Furthermore, we found that TIM-4 interacted with αvβ3 integrin through RGD motif.

Conclusions:

This finding suggests that TIM-4 might be a potential biomarker for NSCLC that promotes lung cancer progression by RGD motif.     

Beclin 1 在 MG132 抗 OVCAR3 卵巢癌细胞中的变化及作用研究简

目的：研究Beclin1在MG132抗OVCAR3卵巢癌细胞中的变化及作用。方法：OVCAR3细胞经小同浓度MG132处理24h后,MTT法检测细胞存活率,Western blot法检测自噬相关Beclin1蛋白的变化。采用细胞转染技术过表达卵巢癌细胞中Beclin1,MG132处理24h后,MTT法检测细胞存活率;Hoechst33258进行核染色观察染色质浓缩和核碎片等凋亡特征性形态学改变。采用shRNA技术下调OVCAR3细胞的Beclin1表达,MG132处理细胞,AO染色观察酸性自噬泡的形成。结果：与空白对照组比较,1、2、5和10μmol/L浓度的MG132作用24h均能明显抑制OVCAR3细胞的生长（均P〈0．05）,5μmol／L浓度接近半抑制率;而且5μmol／L和10μmol／L浓度的MG132作用24h能显著诱导OVCAR3细胞的Beclin1蛋白水平下降（P=0．001）。与卒质粒转染组对比,过表达Beclin1的卵巢癌细胞在MG132处理后核的凋亡明显增加;细胞存活率明显降低,（P=0．00089）。下调卵巢癌细胞中Beclin1表达后,MG132诱导的酸性囊泡蓄积无改变。结论：MG132使OVCAR3细胞中Beelin1降低,Beclin1具有增强MG132抗OVCAR3的作用,但该怍用与自噬无关。