HIF-1alpha determines the metastatic potential of gastric cancer cells. Br J Cancer. 2009;100:772-781. [PMID: 19223895 PMCID: PMC2653758 DOI: 10.1038/sj.bjc.6604919]

Extracellular vesicles as modulators of monocyte and macrophage function in tumors

The tumor microenvironment (TME) harbors several cell types, such as tumor cells, immune cells, and non-immune cells. These cells communicate through several mechanisms, such as cell-cell contact, cytokines, chemokines, and extracellular vesicles (EVs). Tumor-derived vesicles are known to have the ability to modulate the immune response. Monocytes are a subset of circulating innate immune cells and play a crucial role in immune surveillance, being recruited to tissues where they differentiate into macrophages. In the context of tumors, it has been observed that tumor cells can attract monocytes to the TME and induce their differentiation into tumor-associated macrophages with a pro-tumor phenotype. Tumor-derived EVs have emerged as essential structures mediating this process. Through the transfer of specific molecules and signaling factors, tumor-derived EVs can shape the phenotype and function of monocytes, inducing the expression of cytokines and molecules by these cells, thus modulating the TME towards an immunosuppressive environment.

Influence of high altitude on the expression of HIF-1 and on the prognosis of Ecuadorian patients with gastric adenocarcinoma

Since the incidence of gastric adenocarcinoma (GA) is high in populations living at high altitudes, we evaluated the influence of altitude on the expression of HIF-1 and survival of Ecuadorian GA patients. Method: 155 GA cases were studied: 56 from coastal (GAC) and 99 from mountainous regions (GAM), and 74 non-GA controls (25 coast and 49 mountain). The expression of HIF-1/HER2 was analyzed by immunohistochemistry. Analyses were performed using Fisher's exact and Breslow-Day tests for homogeneity and Kaplan-Meier curves and restricted median survival time ΔRMST. Results: HIF-1 was overexpressed in normal/inflamed gastric mucosa, especially in mountainous non-GA patients (p = 0.001). There was no difference between GAC and GAM in terms of age/gender, HIF-1/HER2 expression, stage/tumor location. Median survival at 120 months was significantly higher among GAC, with a difference (ΔRMST) of 43.7 months (95% CI 29.5, 57.8) (p < 0.001) and those with positive HIF-1 expression: ΔRMST 26.6 months (95% CI 11.0, 42.1) (p < 0.001). Positive HIF-1 expression was associated with better GAM survival, with ΔRMST 33.6 months (95% CI 14.2, 52.9) (p < 0.001). Conclusion: Despite the limitations of this retrospective study, GA patients in the coastal region and those who expressed HIF-1 exhibited a better prognosis, but this factor was associated with better survival only in the mountain region.

MicroRNA-574-3p Regulates HIF-α Isoforms Promoting Gastric Cancer Epithelial-Mesenchymal Transition via Targeting CUL2

BACKGROUND

Gastric cancer (GC) is the third leading cause of cancer-related deaths worldwide. MicroRNAs (miRNAs) have been widely validated as potential biomarkers for cancer treatment and diagnosis.

AIMS

This paper intends to study the effect and specific mechanism of miR-574-3p/CUL2 axis in GC.

METHODS

The miR-574-3p expression in GC tissues and cell lines was analyzed by reverse transcription polymerase chain reaction (RT-PCR). GC cell (N87) proliferation, migration and invasion were determined by the Brdu assay and Transwell assay, respectively. The tumor xenotransplantation model was established in vivo to test the effect of miR-574-3p or Cullin 2 (CUL2) on tumor growth. The relationship between miR-574-3p and CUL2 was predicated by bioinformatic analysis and verified by dual-luciferase reporter assay and RIP experiment. The expression of CUL2, hypoxia-induced transcription factor-1α (HIF-1α) as well as E-cadherin, Snail and Vimentin was monitored by western blot and immunohistochemistry.

RESULTS

miR-574-3p was overexpressed in GC tissues and cells. Forced upregulation of miR-574-3p enhanced proliferation, migration, invasion and epithelial-mesenchymal transition (EMT) of GC cells (N87), while downregulation of miR-574-3p resulted in reverse effects. Additionally, miR-574-3p promoted N87 cells growth and EMT in vivo. CUL2 was negatively regulated by miR-574-3p in N87 cells, and upregulation of CUL2 repressed the malignant behaviors of N87 cells. Moreover, CUL2 directly interacted with HIF-1α and suppressed HIF-1α expression both in vitro and in vivo.

CONCLUSIONS

miR-574-3p targeted CUL2 to upregulate HIF-1α, thus facilitating the progression of GC.

HIF in Gastric Cancer: Regulation and Therapeutic Target

HIF means hypoxia-inducible factor gene family, and it could regulate various biological processes, including tumor development. In 2021, the FDA approved the new drug Welireg for targeting HIF-2a, and it is mainly used to treat von Hippel-Lindau syndrome, which demonstrated its good prospects in tumor therapy. As the fourth deadliest cancer worldwide, gastric cancer endangers the health of people all across the world. Currently, there are various treatment methods for patients with gastric cancer, but the five-year survival rate of patients with advanced gastric cancer is still not high. Therefore, here we reviewed the regulatory role and target role of HIF in gastric cancer, and provided some references for the treatment of gastric cancer.

The HIF-1α as a Potent Inducer of the Hallmarks in Gastric Cancer

Simple Summary

Gastric cancer is one of the most aggressive tumors in the clinic that is resistant to chemotherapy. Gastric tumors are rich in hypoxic niches, and high expression of hypoxia-inducible factor-1α is associated with poor prognosis. Therefore, strategies that target hypoxia-inducible factor-1α signaling may be highly effective in gastric cancer treatment. However, the precise mechanisms by which hypoxia-inducible factor-1α induces tumor hallmarks in gastric cancer are yet unrevealed. Here, we review the role of hypoxia-inducible factor-1α as a potent inducer of the cancer hallmarks in gastric cancer to provide a broad perspective and reveal missing links investigating which may offer new strategies to target hypoxia-inducible factor-1α signaling in gastric cancer.

Abstract

Hypoxia is the principal architect of the topographic heterogeneity in tumors. Hypoxia-inducible factor-1α (HIF-1α) reinforces all hallmarks of cancer and donates cancer cells with more aggressive characteristics at hypoxic niches. HIF-1α potently induces sustained growth factor signaling, angiogenesis, epithelial–mesenchymal transition, and replicative immortality. Hypoxia leads to the selection of cancer cells that evade growth suppressors or apoptotic triggers and deregulates cellular energetics. HIF-1α is also associated with genetic instability, tumor-promoting inflammation, and escape from immunity. Therefore, HIF-1α may be an important therapeutic target in cancer. Despite that, the drug market lacks safe and efficacious anti-HIF-1α molecules, raising the quest for fully unveiling the complex interactome of HIF-1α in cancer to discover more effective strategies. The knowledge gap is even wider in gastric cancer, where the number of studies on hypoxia is relatively low compared to other well-dissected cancers. A comprehensive review of the molecular mechanisms by which HIF-1α induces gastric cancer hallmarks could provide a broad perspective to the investigators and reveal missing links to explore in future studies. Thus, here we review the impact of HIF-1α on the cancer hallmarks with a specific focus on gastric cancer.

Quantification of the Landscape for Revealing the Underlying Mechanism of Intestinal-Type Gastric Cancer

Gastric cancer is a daunting disease with a tragic impact on global health. It is the fourth most common cancer and has become the second most frequent cause of cancer death in recent times. According to the Lauren classification, gastric cancer can be classified into two types: intestinal and diffuse. Intestinal-type gastric cancer (IGC) is more common in elderly people, and atrophic gastritis (AG) and intestinal metaplasia (IM) have been proven to be the main premalignant causes of intestinal-type gastric cancer. In turn, Helicobacter pylori infection has been identified as the most significant cause of AG and IM. In this study, we determine the mechanism of IGC progression and how H. pylori infection induces IGC. Through researching the relevant literature, we identified the key genes associated with gastric cancer and the specific genes associated with IGC. We then use hese genes to build up a gene regulatory network for IGC. Based on this gene regulatory network, we quantify the IGC landscape. Within this landscape, there are three stable states, which are classified as the normal, AG, and gastric cancer states. Through landscape topography, we can determine the biological features and progression process of IGC. To investigate the influence of H. pylori infection on IGC, we simulated different degrees of H. pylori infection. As the H. pylori infection becomes more serious, the landscape topography changes accordingly. A fourth state, named the intestinal metaplasia (IM) state, emerges on the landscape and is associated with a very high risk of developing gastric cancer. The emergence of this state is due to the interactions/regulations among genes. Through variations in the landscape topography, we can determine the influence of H. pylori infection on IGC. Finally, we use global sensitivity analysis to research the regulations most sensitive to IGC prevention or therapies. This study presents a new approach and a novel model with which to explore the mechanism of IGC. The simulations of different degrees of H. pylori infection can provide us with a systematic view of IGC progression. The key regulations found can give us some insight and guidance for clinical trials and experimental studies.

Long-term oncological outcomes after oral cancer surgery using propofol-based total intravenous anesthesia versus sevoflurane-based inhalation anesthesia: A retrospective cohort study

Background

Previous studies have shown that the anesthetic technique may influence long-term outcomes after cancer surgery. However, the association between the anesthetic technique and long-term oncological outcomes after oral cancer surgery remains unclear. Therefore, we conducted this study to address this gap.

Methods

We reviewed the electronic medical records of patients who underwent elective oral cancer surgery between January 2014 and December 2015. The patients were grouped based on the anesthesia maintenance: either propofol or sevoflurane. Propensity score matching in a 1:1 ratio was performed to deal with the potential confounding effects of baseline characteristics. Univariate and multivariate Cox regression analyses were performed to compare hazard ratios (HRs) and identify the risk factors for death and recurrence. Survival analysis was performed using the Kaplan–Meier method, and survival curves were constructed from the date of surgery to death.

Results

In total, 1347 patients were eligible for analysis, with 343 and 1004 patients in the propofol and sevoflurane groups, respectively. After propensity score matching, 302 patients remained in each group. Kaplan–Meier survival curves demonstrated the 5-year overall and recurrence-free survival rates of 59.3% and 56.0% and 62.7% and 56.5% in the propofol and sevoflurane groups, respectively. There was no significant difference in overall survival or recurrence-free survival between the groups. The multivariate Cox analysis verified this conclusion with HRs of 1.10 and 1.11 for overall survival and recurrence-free survival, respectively, in the sevoflurane group. Older age, advanced tumor-node-metastasis (TNM) stage, and American Society of Anesthesiologists class III were associated with poor overall survival. Patients with advanced TNM stage and poorly differentiated squamous cell carcinoma had a higher recurrence risk than their counterparts.

Conclusion

The overall and recurrence-free survival rates were similar between propofol-based intravenous anesthesia and sevoflurane volatile anesthesia in patients who underwent oral cancer surgery.

Pan-cancer Bioinformatics Analysis of the Double-edged Role of Hypoxia-inducible Factor 1α (HIF-1α) in Human Cancer

BACKGROUND/AIM

Despite the emergence of cellular, animal, and clinical-based evidence demonstrating a link between hypoxia-inducible factor-1α (HIF-1α) and malignancy, the comprehensive assessment of HIF-1α in pan-cancer patients remains unclear, particularly regarding HIF-1α expression and its association with immune infiltration and immune checkpoint. The present study aimed to investigate the role of HIF-1α expression in various types of malignancies through bioinformatics analysis.

MATERIALS AND METHODS

We investigated the expression and prognostic value of HIF-1α in pan-cancer based on the TCGA (The Cancer Genome Atlas) dataset. The abundance of immune infiltration was estimated by xCell immune deconvolution methods. We investigated the relationship of HIF-1α expression with immune infiltration and immune checkpoint gene expression, with a focus on gastric adenocarcinoma (STAD) and lung squamous cell carcinoma (LUSC).

RESULTS

HIF-1α expression had different effects on the prognosis of various cancers. In contrast to the protective effect of HIF-1α expression in LUSC, high levels of HIF-1α expression played a detrimental role in the survival of STAD patients. There was a significant positive correlation between HIF-1α expression and immune infiltration in STAD patients, including regulatory T-cells (Tregs), T-cell CD4+ Th2, neutrophils, M1 and M2 macrophages. In addition, immune checkpoint molecules showed different HIF-1α-related profiles in various carcinomas.

CONCLUSION

A relatively comprehensive view of the oncogenic role of HIF-1α in various tumors based on a pan-cancer analysis is provided in this study. HIF-1α may be considered a poor prognostic biomarker for STAD and, moreover, it may be involved in regulating tumor immune infiltration.

Stabilization but no functional influence of HIF-1α expression in the intestinal epithelium during Salmonella Typhimurium infection

The hypoxia-inducible transcription factor 1 (HIF-1) has been shown to enhance microbial killing and to ameliorate the course of bacterial infections. While the impact of HIF-1 on inflammatory diseases of the gut has been studied intensively, its function in bacterial infections of the gastrointestinal tract remains largely elusive. With the help of a publicly available gene expression data set, we could infer significant activation of HIF-1 after oral infection of mice with Salmonella Typhimurium. Immunohistochemistry and western blot analysis confirmed marked HIF-1α protein stabilization, especially in the intestinal epithelium. This prompted us to analyze conditional Hif1a-deficient mice to examine cell type-specific functions of HIF-1 in this model. Our results demonstrate enhanced non-canonical induction of HIF-1 activity upon Salmonella infection in the intestinal epithelium as well as in macrophages. Surprisingly, Hif1a deletion in intestinal epithelial cells did not impact on inflammatory gene expression, bacterial spread or disease outcome. In contrast, Hif1a deletion in myeloid cells enhanced intestinal Cxcl2 expression and reduced the cecal Salmonella load. In vitro, HIF-1α-deficient macrophages showed an overall impaired transcription of mRNA encoding pro-inflammatory factors, however, intracellular survival of Salmonella was not impacted by HIF-1α deficiency.

Analysis of ER-Phagy in Cancer Drug Resistance

The ability of the cancer cells to survive hostile environment depends on their cellular stress response mechanisms. These mechanisms also help them to develop resistance to chemotherapies. Autophagy and more specifically organelle specific autophagy is one such adaptive mechanism that promotes drug resistance in cancer cells. Endoplasmic reticulum-specific autophagy or ER-phagy has been more recently described to overcome ER-stress through the degradation of damaged ER. ER-resident proteins such as FAM134B act as ER-phagy receptors to specifically target damaged ER for degradation through autophagy. Moreover, we had recently deciphered that ER-phagy facilitates cancer cell survival during hypoxic stress and we predict that this process could play a critical role in the development of drug resistance in cancer cells. Therefore, here, we provide a lay description of how ER-phagy could be investigated biochemically by Western blot analysis and silencing ER-phagy receptor genes using small interfering RNAs (siRNA).

Tumour Microenvironment Stress Promotes the Development of Drug Resistance

Multi-drug resistance (MDR) is a leading cause of cancer-related death, and it continues to be a major barrier to cancer treatment. The tumour microenvironment (TME) has proven to play an essential role in not only cancer progression and metastasis, but also the development of resistance to chemotherapy. Despite the significant advances in the efficacy of anti-cancer therapies, the development of drug resistance remains a major impediment to therapeutic success. This review highlights the interplay between various factors within the TME that collectively initiate or propagate MDR. The key TME-mediated mechanisms of MDR regulation that will be discussed herein include (1) altered metabolic processing and the reactive oxygen species (ROS)-hypoxia inducible factor (HIF) axis; (2) changes in stromal cells; (3) increased cancer cell survival via autophagy and failure of apoptosis; (4) altered drug delivery, uptake, or efflux and (5) the induction of a cancer stem cell (CSC) phenotype. The review also discusses thought-provoking ideas that may assist in overcoming the TME-induced MDR. We conclude that stressors from the TME and exposure to chemotherapeutic agents are strongly linked to the development of MDR in cancer cells. Therefore, there remains a vast area for potential research to further elicit the interplay between factors existing both within and outside the TME. Elucidating the mechanisms within this network is essential for developing new therapeutic strategies that are less prone to failure due to the development of resistance in cancer cells.

CIRP promotes the progression of non-small cell lung cancer through activation of Wnt/β-catenin signaling via CTNNB1

BACKGROUND

Cold-inducible RNA binding protein (CIRP) is a newly discovered proto-oncogene. In this study, we investigated the role of CIRP in the progression of non-small cell lung cancer (NSCLC) using patient tissue samples, cultured cell lines and animal lung cancer models.

METHODS

Tissue arrays, IHC and HE staining, immunoblotting, and qRT-PCR were used to detect the indicated gene expression; plasmid and siRNA transfections as well as viral infection were used to manipulate gene expression; cell proliferation assay, cell cycle analysis, cell migration and invasion analysis, soft agar colony formation assay, tail intravenous injection and subcutaneous inoculation of animal models were performed to study the role of CIRP in NSCLC cells; Gene expression microarray was used to select the underlying pathways; and RNA immunoprecipitation assay, biotin pull-down assay, immunopurification assay, mRNA decay analyses and luciferase reporter assay were performed to elucidate the mechanisms. The log-rank (Mantel-Cox) test, independent sample T-test, nonparametric Mann-Whitney test, Spearman rank test and two-tailed independent sample T-test were used accordingly in our study.

RESULTS

Our data showed that CIRP was highly expressed in NSCLC tissue, and its level was negatively correlated with the prognosis of NSCLC patients. By manipulating CIRP expression in A549, H460, H1299, and H1650 cell lines, we demonstrated that CIRP overexpression promoted the transition of G1/G0 phase to S phase and the formation of an enhanced malignant phenotype of NSCLC, reflected by increased proliferation, enhanced invasion/metastasis and greater tumorigenic capabilities both in vitro and in vivo. Transcriptome sequencing further demonstrated that CIRP acted on the cell cycle, DNA replication and Wnt signaling pathway to exert its pro-oncogenic action. Mechanistically, CIRP directly bound to the 3'- and 5'-UTRs of CTNNB1 mRNA, leading to enhanced stability and translation of CTNNB1 mRNA and promoting IRES-mediated protein synthesis, respectively. Eventually, the increased CTNNB1 protein levels mediated excessive activation of the Wnt/β-catenin signaling pathway and its downstream targets C-myc, COX-2, CCND1, MMP7, VEGFA and CD44.

CONCLUSION

Our results support CIRP as a candidate oncogene in NSCLC and a potential target for NSCLC therapy.

Saffron anti-metastatic properties, ancient spice novel application

Crocus sativus L. (saffron), was applied as a spice, food colorant and medicine since four millennia ago and has been used as a remedy for various maladies. In the last three decades, the anti-primary tumor properties of saffron and its main carotenoids, crocin and crocetin, have been well explored. Despite the fact that metastasis is the leading cause of death in cancer patients, the anti-metastatic potential of saffron and its carotenoids has been surveyed only this decade. This review aims to provide an unprecedented overview of the anti-metastatic effects of saffron, crocin and crocetin, and the mechanisms underlying these effects. Investigations on various cancers demonstrated the anti-migratory, anti-invasion, anti-angiogenic potentials of saffron and its carotenoids, as well as their effects suppressing cell-ECM adhesion and enhancing cell-cell attachment. Saffron and its carotenoids exert their impact through different mechanisms such as reduction of CD34 and suppression of Wnt/β-catenin, Ras/ERK, P38, DCLK1, EMT, matrix metalloproteinases and urokinases. Crocin displayed more effective anti-metastatic potency, in comparison with saffron extract and crocetin. The bioaccessibility/bioavailability, nontoxicity on normal cells, confirmed anti-tumor efficiency and the recent evidence on the anti-metastatic potential of saffron and its carotenoids, recommends them as a propitious multipotent dietary agent and herbal medicine.

HACE1 blocks HIF1α accumulation under hypoxia in a RAC1 dependent manner

Uncovering the mechanisms that underpin how tumor cells adapt to microenvironmental stress is essential to better understand cancer progression. The HACE1 (HECT domain and ankyrin repeat-containing E3 ubiquitin-protein ligase) gene is a tumor suppressor that inhibits the growth, invasive capacity, and metastasis of cancer cells. However, the direct regulatory pathways whereby HACE1 confers this tumor-suppressive effect remain to be fully elucidated. In this report, we establish a link between HACE1 and the major stress factor, hypoxia-inducible factor 1 alpha (HIF1α). We find that HACE1 blocks the accumulation of HIF1α during cellular hypoxia through decreased protein stability. This property is dependent on HACE1 E3 ligase activity and loss of Ras-related C3 botulinum toxin substrate 1 (RAC1), an established target of HACE1 mediated ubiquitinylation and degradation. In vivo, genetic deletion of Rac1 reversed the increased HIF1α expression observed in Hace1^-/- mice in murine KRas^G12D-driven lung tumors. An inverse relationship was observed between HACE1 and HIF1α levels in tumors compared to patient-matched normal kidney tissues, highlighting the potential pathophysiological significance of our findings. Together, our data uncover a previously unrecognized function for the HACE1 tumor suppressor in blocking HIF1α accumulation under hypoxia in a RAC1-dependent manner.

Hypoxia, partial EMT and collective migration: Emerging culprits in metastasis

Epithelial-mesenchymal transition (EMT) is a cellular biological process involved in migration of primary cancer cells to secondary sites facilitating metastasis. Besides, EMT also confers properties such as stemness, drug resistance and immune evasion which can aid a successful colonization at the distant site. EMT is not a binary process; recent evidence suggests that cells in partial EMT or hybrid E/M phenotype(s) can have enhanced stemness and drug resistance as compared to those undergoing a complete EMT. Moreover, partial EMT enables collective migration of cells as clusters of circulating tumor cells or emboli, further endorsing that cells in hybrid E/M phenotypes may be the 'fittest' for metastasis. Here, we review mechanisms and implications of hybrid E/M phenotypes, including their reported association with hypoxia. Hypoxia-driven activation of HIF-1α can drive EMT. In addition, cyclic hypoxia, as compared to acute or chronic hypoxia, shows the highest levels of active HIF-1α and can augment cancer aggressiveness to a greater extent, including enriching for a partial EMT phenotype. We also discuss how metastasis is influenced by hypoxia, partial EMT and collective cell migration, and call for a better understanding of interconnections among these mechanisms. We discuss the known regulators of hypoxia, hybrid EMT and collective cell migration and highlight the gaps which needs to be filled for connecting these three axes which will increase our understanding of dynamics of metastasis and help control it more effectively.

TSGA10 Over Expression Decreases Metastasic and Metabolic Activity by Inhibiting HIF-1 in Breast Cancer Cells

BACKGROUND AND AIMS

HIF-1 is an important factor that play critical roles in metabolic and metastasis activity of cancer cells. HIF-1 activity can have regulated by TSGA10. Although decreased metastatic activity of cancer cells through TSGA10 inhibitory effect on HIF-1 have already been demonstrated, changes in cancer metabolism and its impact on metastasis in breast cancer is still not determined. So, we aimed to investigate TSGA10 overexpression effect on breast cancer metabolism as well as metastasis.

METHODS

TSGA10 vector was designed and stable transfected into MCF-7 cells. The efficiency of transfection was assessed by Real-time PCR and western blot. After HIF-1 induction at high and low glucose conditions, cell proliferation, cell cycle profile, metabolic and metastasis activity of cells were assessed. Furthermore, biomarker expressions of ER, PR, HER2, Ki67 and E-cadherin in cancer cells were measured.

RESULTS

Our results showed decrease of cell proliferation and cell cycle arrest in G2/M phase. Reduce expression of GLUT1, lactate production and reactive oxygen species (ROS) below their basal level indicated decreased metabolic activity. Furthermore, metastatic activity reduction was shown by decrease expression of different involve genes in metastasis, protelytic activity of MMOLP-2/9, carbonic anhydrase (CA) IX activity and increase of wound closure. Moreover, except for E-cadherin, expression of ER, PR, HER2 and Ki67 was declined in cells.

CONCLUSION

Our findings indicated that TSGA10 overexpression could decrease the metastatic and metabolic activity of cancer cells through its inhibitory effect on HIF-1 activity. Therefore, TSGA10 could be considered in the research for therapeutic candidates in cancer.

Effects of chronic low-dose aspirin treatment on tumor prevention in three mouse models of intestinal tumorigenesis

Although early detection and treatment of colorectal cancer (CRC) have improved, it remains a significant health-care problem with high morbidity and mortality. Data indicate that long-term intake of low-dose aspirin reduces the risk of CRC; however, the mechanisms underlying this chemopreventive effect are still unclear. Different mouse models for inflammation-associated, sporadic, and hereditary CRC were applied to assess the efficacy and mechanism of low-dose aspirin on tumor prevention. An initial dosing study performed in healthy mice indicates that aspirin at a dose of 25 mg/kg/d has a similar pharmacodynamic effect as low-dose aspirin treatment in human subjects (100 mg/d). Chronic low-dose aspirin treatment suppresses colitis-associated and to a lesser extent spontaneous tumorigenesis in mice. Aspirin's antitumor effect is most pronounced in a preventive approach when aspirin administration starts before the tumor-initiating genotoxic event and continues for the duration of the experiment. These effects are not associated with alterations in cell proliferation, apoptosis, or activation of signaling pathways involved in CRC. Aspirin-induced reduction in tumor burden is accompanied by inhibition of thromboxane B₂ formation, indicating reduced platelet activation. Aspirin treatment also results in decreased colonic prostaglandin E₂ formation and tumor angiogenesis. With respect to colitis-triggered tumorigenesis, aspirin administration is associated with a reduction in inflammatory activity in the colon, as indicated by decreased levels of pro-inflammatory mediators, and tumor-associated iNOS-positive macrophages. Our results suggest that low-dose aspirin represents an effective antitumor agent in the context of colon tumorigenesis primarily due to its well-established cyclooxygenase inhibition effects.

Hypoxic environment may enhance migration/penetration of endocrine resistant MCF7- derived breast cancer cells through monolayers of other non-invasive cancer cells in vitro

The response of cancer cells to hypoxic conditions found within the interior of a tumor mass is mediated through the hypoxia inducible factor (HIF) cascade and is thought to promote metastasis. However, given their distant proximity from blood vessels as compared to normoxic cells at the vascularised tumor periphery, it is uncertain if these cells can migrate through the tumor mass to gain access. Hypoxia was simulated by exposure to cobalt chloride or deferoxamine in normal (MCF10A) and cancerous [estrogen receptor (ER)−ve (pII), and ER +ve (YS1.2/ EII)] cells. In this report, HIF1α expression and localization was measured using western blotting, ELISA, and immunofluorescence, cell proliferation by MTT assay, motility and invasion by wound healing, live cell imaging, matrigel and co-culture in chambered slides. We found that the expression and nuclear translocation of HIF1α was significantly elevated by hypoxia, which inhibited cell proliferation, but significantly increased motility of pII cells and their penetration into and through a dense layer of adjacent EII cells, as well as their selective emergence out of a co-culture. These data suggest that endocrine resistant pII cancer cells, having undergone epithelial to mesenchymal transition are able to penetrate through other cell layers, with possible enhancement in response to hypoxia.

Anesthetics and long-term survival after cancer surgery-total intravenous versus volatile anesthesia: a retrospective study

Background

Intravenous anesthesia has been reported to have a favorable effect on the prognosis of cancer patients. This study was performed to analyze data regarding the relation between anesthetics and the prognosis of cancer patients in our hospital.

Methods

The medical records of patients who underwent surgical resection for gastric, lung, liver, colon, and breast cancer between January 2006 and December 2009 were reviewed. Depending on the type of anesthetic, it was divided into total intravenous anesthesia (TIVA) or volatile inhaled anesthesia (VIA) group. The 5-year overall survival outcomes were analyzed by log-rank test. Cox proportional hazards modeling was used for sensitivity.

Results

The number of patients finally included in the comparison after propensity matching came to 729 in each group. The number of surviving patients at 5 years came to 660 (90.5%) in the TIVA and 673 (92.3%) in the VIA. The type of anesthetic did not affect the 5-year survival rate according to the log-rank test (P = 0.21). Variables associated with a significant increase in the hazard of death after multivariable analysis were male sex and metastasis at surgery.

Conclusions

There were no differences in 5-year overall survival between two groups in the cancer surgery.

Trial registration

Trial registration: CRIS KCT0004101. Retrospectively registered 28 June 2019.

CXCR4-targeted PET imaging using 64Cu-AMD3100 for detection of Waldenström Macroglobulinemia

Objective:  Waldenström Macroglobulinemia (WM) is a rare B-cell malignancy characterized by secretion of immunoglobulin M and cancer infiltration in the bone marrow. Chemokine receptor such as CXCR4 and hypoxic condition in the bone marrow play crucial roles in cancer cell trafficking, homing, adhesion, proliferation, survival, and drug resistance. Herein, we aimed to use CXCR4 as a potential biomarker to detect hypoxic-metastatic WM cells in the bone marrow and in the circulation by using CXCR4-detecting radiopharmaceutical.Methods: We radiolabeled a CXCR4-inhibitor (AMD3100) with ⁶⁴Cu and tested its binding to WM cells with different levels of CXCR4 expression using gamma counter in vitro. The accumulation of this radiopharmaceutical tracer was tested in vivo in subcutaneous and intratibial models using PET/CT scan. In addition, PBMCs spiked with different amounts of WM cells ex vivo were detected using gamma counting.Results: In vitro, ⁶⁴Cu-AMD3100 binding to WM cell lines demonstrated a direct correlation with the level of CXCR4 expression, which was increased in cells cultured in hypoxia with elevated levels of CXCR4, and decreased in cells with CXCR4 and HIF-1α knockout. Moreover, ⁶⁴Cu-AMD3100 detected localized and circulating CXCR4^high WM cells with high metastatic potential.Conclusions: In conclusion, we developed a molecularly targeted system, ⁶⁴Cu-AMD3100, which binds to CXCR4 and specifically detects WM cells with hypoxic phenotype and metastatic potential in the subcutaneous and intratibial models. These preliminary findings using CXCR4-detecting PET radiopharmaceutical tracer indicate a potential technology to predict high-risk patients for the progression to WM due to metastatic potential.

Mutant p53 induces a hypoxia transcriptional program in gastric and esophageal adenocarcinoma

Despite the propensity for gastric and esophageal adenocarcinomas to select for recurrent missense mutations in TP53, the precise functional consequence of these mutations remains unclear. Here we report that endogenous mRNA and protein levels of mutant p53 were elevated in cell lines and patients with gastric and esophageal cancer. Functional studies showed that mutant p53 was sufficient, but not necessary, for enhancing primary tumor growth in vivo. Unbiased genome-wide transcriptome analysis revealed that hypoxia signaling was induced by mutant p53 in 2 gastric cancer cell lines. Using real-time in vivo imaging, we confirmed that hypoxia reporter activity was elevated during the initiation of mutant p53 gastric cancer xenografts. Unlike HIF co-factor ARNT, HIF1α was required for primary tumor growth in mutant p53 gastric cancer. These findings elucidate the contribution of missense p53 mutations in gastroesophageal malignancy and indicate that hypoxia signaling rather than mutant p53 itself may serve as a therapeutic vulnerability in these deadly set of cancers.

Microenvironment-regulated lncRNA-HAL is able to promote stemness in breast cancer cells

Multicellular Tumor Spheroids culture (MCTS) is an in vitro model mimicking the characteristics of the tumor microenvironment, such as hypoxia and acidosis, resulting in the presence of both proliferating and quiescent cell populations. lncRNA's is a novel group of regulatory molecules that participates in the acquisition of tumorigenic phenotypes. In the present work we evaluated the oncogenic association of an uncharacterized lncRNA (lncRNA-HAL) in the tumorigenic phenotype induced by the MCTS microenvironment. We measured lncRNA-HAL expression level in MCF-7-MCTS populations and under different hypoxic conditions by RT-qPCR. Afterwards, we silenced lncRNA-HAL expression by shRNAs and evaluated its effect in MCF-7 transcriptome (by RNAseq) and validated the modified cellular processes by proliferation, migration, and stem cells assays. Finally, we analyzed which proteins interacts with lncRNA-HAL by ChIRP assay, to propose a possible molecular mechanism for this lncRNA. We found that lncRNA-HAL is overexpressed in the internal quiescent populations (p27 positive populations) of MCF-7-MCTS, mainly in the quiescent stem cell population, being hypoxia one of the microenvironmental cues responsible of its overexpression. Transcriptome analysis of lncRNA-HAL knockdown MCF7 cells revealed that lncRNA-HAL effect is associated with proliferation, migration and cell survival mechanisms; moreover, lncRNA-HAL silencing increased cell proliferation and impaired cancer stem cell proportion and function, resulting in decreased tumor grafting in vivo. In addition, we found that this lncRNA was overexpressed in triple-negative breast cancer patients. Analysis by ChIRP assay showed that this nuclear lncRNA binds to histones and hnRNPs suggesting a participation at the chromatin level and transcriptional regulation. The results obtained in the present work suggest that the function of lncRNA-HAL is associated with quiescent stem cell populations, which in turn is relevant due to its implications in cancer cell survival and resistance against treatment in vivo. Altogether, our data highlights a new lncRNA whose expression is regulated by the tumor microenvironment and associated to stemness in breast cancer.

Microbial carcinogenesis: Lactic acid bacteria in gastric cancer

While Helicobacter pylori is a fundamental risk factor, gastric cancer (GC) aetiology involves combined effects of microbial (both H. pylori and non-H. pylori), host and environmental factors. Significant differences exist between the gastric microbiome of those with gastritis, intestinal metaplasia and GC, suggesting that dysbiosis in the stomach is dynamic and correlates with progression to GC. Most notably, a consistent increase in abundance of lactic acid bacteria (LAB) has been observed in GC patients including Streptococcus, Lactobacillus, Bifidobacterium and Lactococcus. This review summarises how LAB can influence GC by a number of mechanisms that include supply of exogenous lactate -a fuel source for cancer cells that promotes inflammation, angiogenesis, metastasis, epithelial-mesenchymal transition and immune evasion-, production of reactive oxygen species and N-nitroso compounds, as well as anti-H. pylori properties that enable colonization by other non-H. pylori carcinogenic pathobionts.

Crocin inhibits the migration, invasion, and epithelial-mesenchymal transition of gastric cancer cells via miR-320/KLF5/HIF-1α signaling

The biological activities of crocin, one of the main bioactive compounds of saffron, include anti-inflammatory, antioxidant, antidepressant, and anticancer effects. Crocin has been shown to trigger the apoptosis of gastric cancer cells, but its effect on the metastasis of gastric cancer cells remains unclear. Krüppel-like factor 5 (KLF5) and hypoxia-inducible factor-1α (HIF-1α) are important transcription factors in the development of gastric cancer. KLF5 and HIF-1α expression were analyzed in gastric cancer tissues and cells. Following exposure to crocin, AGS and HGC-27 gastric cancer cells were assessed with regard to migration, invasion, and epithelial-mesenchymal transition (EMT) as well as the expression of KLF5, HIF-1α, and microRNA-320 (miR-320). The miR-320/KLF5/HIF-1α signaling pathway became the focus for further investigation of the mechanism of crocin in gastric cancer cell migration, invasion, and EMT. KLF5 and HIF-1α expression were elevated in gastric cancer tissues and cells, and KLF5 expression was positively correlated with the HIF-1α level in gastric cancer tissues. Crocin was associated with reduced expression of KLF5 and HIF-1α, whereas miR-320 expression was increased. Crocin also inhibited the migration, invasion, and EMT of gastric cancer cells. Upregulation of KLF5 attenuated crocin's function and elevated HIF-1α expression. Dual-luciferase reporter assay demonstrated that KLF5 was a target gene of miR-320. Crocin modulated KLF5 expression via elevation of miR-320 expression. In conclusion, crocin inhibits the EMT, migration, and invasion of gastric cancer cells, and this activity is mediated through miR-320/KLF5/HIF-1α signaling.

Hypoxia Induced ER Stress Response as an Adaptive Mechanism in Cancer

It is evident that regions within tumors are deprived of oxygen, which makes the microenvironment hypoxic. Cancer cells experiencing hypoxia undergo metabolic alterations and cytoprotective adaptive mechanisms to survive such stringent conditions. While such mechanisms provide potential therapeutic targets, the mechanisms by which hypoxia regulates adaptive responses-such as ER stress response, unfolded protein response (UPR), anti-oxidative responses, and autophagy-remain elusive. In this review, we summarize the complex interplay between hypoxia and the ER stress signaling pathways that are activated in the hypoxic microenvironment of the tumors.

Total Intravenous Anesthesia versus Inhalation Anesthesia for Breast Cancer Surgery

EDITOR’S PERSPECTIVE

What We Know about This Topic

IV anesthesia may impair anticancer immunity less than volatile anesthesia and therefore reduce recurrence risk

What This Article Tells Us That Is New

In a large propensity-matched retrospective cohort analysis, the authors compared total IV and volatile anesthesia for breast cancer surgery

Recurrence hazard was similar with each approach

Selection of IV or volatile anesthesia should be based on factors other than cancer recurrence

Background

The association between type of anesthesia used and recurrence of cancer remains controversial. This retrospective cohort study compared the influence of total IV anesthesia and inhalation anesthesia on the primary outcome of recurrence-free survival after breast cancer surgery.

Methods

The authors reviewed the electronic medical records of patients who had breast cancer surgery at a tertiary care teaching hospital between January 2005 and December 2013. The patients were grouped according to whether IV or inhalation anesthesia was used for surgery. Propensity score matching was used to account for differences in baseline characteristics. Kaplan–Meier survival curves were constructed to evaluate the influence of type of anesthesia on recurrence-free survival and overall survival. The risks of cancer recurrence and all-cause mortality were compared between each type of anesthesia.

Results

Of 7,678 patients who had breast cancer surgery during the study period, data for 5,331 patients were available for analysis (IV group, n = 3,085; inhalation group, n = 2,246). After propensity score matching, 1,766 patients remained in each group. Kaplan–Meier survival curves showed that there was no significant difference in recurrence-free survival or overall survival between the two groups, with 5-yr recurrence-free survival rates of 93.2% (95% CI, 91.9 to 94.5) in the IV group and 93.8% (95% CI, 92.6 to 95.1) in the inhalation group. Inhalation anesthesia had no significant impact on recurrence-free survival (hazard ratio, 0.96; 95% CI, 0.69 to 1.32; P = 0.782) or overall survival (hazard ratio, 0.96; 95% CI, 0.69 to 1.33, P = 0.805) when compared with total IV anesthesia.

Conclusions

The authors found no association between type of anesthesia used and the long-term prognosis of breast cancer. The results of this retrospective cohort study do not suggest specific selection of IV or inhalation anesthesia for breast cancer surgery.

Acetylation-mediated Siah2 stabilization enhances PHD3 degradation in Helicobacter pylori-infected gastric epithelial cancer cells

Gastric epithelial cells infected with Helicobacter pylori acquire highly invasive and metastatic characteristics. The seven in absentia homolog (Siah)2, an E3 ubiquitin ligase, is one of the major proteins that induces invasiveness of infected gastric epithelial cells. We find that p300-driven acetylation of Siah2 at lysine 139 residue stabilizes the molecule in infected cells, thereby substantially increasing its efficiency to degrade prolyl hydroxylase (PHD)3 in the gastric epithelium. This enhances the accumulation of an oncogenic transcription factor hypoxia-inducible factor 1α (Hif1α) in H. pylori-infected gastric cancer cells in normoxic condition and promotes invasiveness of infected cells. Increased acetylation of Siah2, Hif1α accumulation, and the absence of PHD3 in the infected human gastric metastatic cancer biopsy samples and in invasive murine gastric cancer tissues further confirm that the acetylated Siah2 (ac-Siah2)-Hif1α axis is crucial in promoting gastric cancer invasiveness. This study establishes the importance of a previously unrecognized function of ac-Siah2 in regulating invasiveness of H. pylori-infected gastric epithelial cells.-Kokate, S. B., Dixit, P., Das, L., Rath, S., Roy, A. D., Poirah, I., Chakraborty, D., Rout, N., Singh, S. P., Bhattacharyya, A. Acetylation-mediated Siah2 stabilization enhances PHD3 degradation in Helicobacter pylori-infected gastric epithelial cancer cells.

HIF-1α promotes ZEB1 expression and EMT in a human bladder cancer lung metastasis animal model

Lung is one of the most common sites for bladder cancer to metastasize. Although the involvement of the epithelial-to-mesenchymal transition (EMT) in bladder cancer progression has been established, the mechanism of EMT induction remains unclear. In order to investigate this, T24-parental (P) and T24-lung (L) bladder cancer cells were obtained from primary tumors and lung metastatic sites of an animal model with orthotopic spontaneous metastatic bladder cancer, according to a protocol previously described. Compared with T24-P cells, mesenchymal-like T24-L cells exhibited an increased ability in tumor invasion and metastasis, as well as an increased expression of hypoxia-inducible factor (HIF)-1α, zinc finger E-box-binding homeobox 1 (ZEB1), vimentin and N-cadherin and lower level of cytokeratin 18 were observed. Mechanistically, it was identified that HIF-1α increases ZEB1 expression and subsequently regulates the expression of EMT-related genes in both HIF-1α knocking down by siRNA and gain-in HIF-1α by hypoxia culture cell models. In addition, the expression of HIF-1α and ZEB1 in bladder cancer tissues were increased compared with normal bladder epithelial tissues, as well as significantly increased in the high-grade, invasive and metastatic bladder cancer tissues compared with low-grade, superficial and non-metastatic bladder cancer tissues by using immune-histochemical staining assay. Notably, the protein level of HIF-1α was positively associated with that of ZEB1 in bladder cancer tissues. Results from the present study indicate that HIF-1α promotes ZEB1 expression and EMT in the T24-L human bladder cancer lung metastasis animal model, suggesting that HIF-1α serves an important function in the metastasis of bladder cancer, and HIF-1α and ZEB1 may be potential targets for inhibiting bladder metastasis in the future.

Tumor microenvironment interruption: a novel anti-cancer mechanism of Proton-pump inhibitor in gastric cancer by suppressing the release of microRNA-carrying exosomes

Poor prognosis of gastric cancer is related to not only malignancy of gastric cancer cells, but also the tumor microenvironment. Thus drugs, which can inhibit both of them, are urgently needed to be explored. Studies on effect of Proton-pump inhibitors (PPIs) in anti-neoplasms are increasing, but is rare in gastric in gastric cancer. Here we investigated how the gastric cancer microenvironment is regulated by PPIs. The objective response rate of gastric cancer patients in our hospital treated by PPIs is investigated. PPIs' effects were further explored by observing the change of microRNAs, cytokines, cellular apoptosis. Bioinformatic pathway analysis of microarray was used to discover the pathway involved in PPIs' regulation of gastric cancer microenvironments. Immunoblotting assays and qRT-PCR were used to define molecular events with PPIs treatment. We report here that PPIs can improve the prognosis of advanced gastric cancer patients; and inhibit the progress of gastric cancer both in vivo and in vitro. Moreover, high dose of PPIs can regulate the pathway associated with tumor malignancy and microenvironment via inhibiting the release of exosomes, which packed microRNAs. PPIs can inhibit the transformation of CAFs (cancer associated fibroblasts) and cytokines released from CAFs. In addition, PPIs inhibit the malignancy of gastric cancer through regulating HIF-1α-FOXO1 axis. High dose of PPIs can inhibit malignancy of gastric cancer and regulate its surrounding tumor microenvironment. This finding suggests that PPIs maybe of potential value as a therapeutic tool for treatment of gastric cancer.

Clinical significance of HIF-1α expression in gastric malignant transformation in people from high altitude area of Qinghai

AIM

To detect the expression of hypoxia inducible factor-1α (HIF-1α) in gastric malignant transformation in people from high altitude area of Qinghai, China.

METHODS

RT-PCR was used to detect the expression of HIF-1α gene in 7 cell lines and 27 pairs of GC and matched tumor adjacent normal gastric mucosa tissues. Using tissue microarray including 57 normal gastric mucosa tissues, 37 chronic atrophic gastritis tissues, 34 intestinal metaplasia tissues, and 146 gastric cancer (GC) tissues, immunohistochemistry (IHC) was performed to detect the level of HIF-1α protein expression.

RESULTS

The expression of HIF-1α at the mRNA level was different in GC cell lines. HIF-1αexpression in AGS, SGC7901, and N87 cells was higher than that in MGC803, BGC823, PAMC82 and MKN45 cells. The level of HIF-1α expression was significantly higher in GC tissues (66.6%, 18/27) compared with normal gastric mucosa tissues (26.3%, 15/57; P < 0.001). IHC data showed that the positive rate of HIF-1α was 64.8% (24/37) in chronic atrophic gastritis tissues, 61.7% (21/34) in intestinal metaplasia tissues, and 56.8% (83/146) in GC tissues, all of which were significantly higher than that in normal tissues (26.3%, 15/57). Expression of HIF-1α was positively associated with age in GC (P < 0.05). Kaplan-Meier analysis showed that patients with a low level of HIF-1α had apparently better survival than those with a high level (P < 0.0001). HIF-1α protein (RR = 3.229, 95%CI: 2.024-5.151) was identified to be an independent risk factor for the outcome of GC patients.

CONCLUSION

High HIF-1α expression is associated with gastric malignant transformation and poor prognosis in high altitude areas.

Heterogenous ribonucleoprotein A18 (hnRNP A18) promotes tumor growth by increasing protein translation of selected transcripts in cancer cells

The heterogenous ribonucleoprotein A18 (hnRNP A18) promotes tumor growth by coordinating the translation of selected transcripts associated with proliferation and survival. hnRNP A18 binds to and stabilizes the transcripts of pro-survival genes harboring its RNA signature motif in their 3′UTRs. hnRNP A18 binds to ATR, RPA, TRX, HIF-1α and several protein translation factor mRNAs on polysomes and increases de novo protein translation under cellular stress. Most importantly, down regulation of hnRNP A18 decreases proliferation, invasion and migration in addition to significantly reducing tumor growth in two mouse xenograft models, melanoma and breast cancer. Moreover, tissue microarrays performed on human melanoma, prostate, breast and colon cancer indicate that hnRNP A18 is over expressed in 40 to 60% of these malignant tissue as compared to normal adjacent tissue. Immunohistochemistry data indicate that hnRNP A18 is over expressed in the stroma and hypoxic areas of human tumors. These data thus indicate that hnRNP A18 can promote tumor growth in in vivo models by coordinating the translation of pro-survival transcripts to support the demands of proliferating cells and increase survival under cellular stress. hnRNP A18 therefore represents a new target to selectively inhibit protein translation in tumor cells.

Hypoxia regulates CD44 expression via hypoxia-inducible factor-1α in human gastric cancer cells

Hypoxia induces proliferation and invasion in cancer cells via hypoxia-inducible factor (HIF)-1α. The cell adhesion molecule cluster of differentiation (CD) 44 has been associated with increased cell invasion and metastasis. Whether hypoxia regulates the expression of CD44 in gastric cancer cells remains to be established. In the current study, the effects of hypoxia on HIF-1α and CD44 expression levels in human gastric cell lines SGC-7901 and BGC-823 were evaluated. The cells were cultured in 1% O₂ for 1 week and then treated with 20 nM rapamycin for 72 h. Cell viability was evaluated using the Cell Counting kit-8 assay, and cell invasion was detected by the Transwell invasion assay. The protein and messenger (m) RNA expression levels of HIF-1α and CD44 were detected using western blotting and reverse transcription-quantitative polymerase chain reaction, respectively. The results revealed that cell viability and invasion increased under hypoxic conditions, but decreased following rapamycin treatment in SGC-7901 and BGC-823 cells. Hypoxia also increased the protein and mRNA expression levels of HIF-1α and CD44 in these two cell lines. However, this hypoxia-induced increase in HIF-1α and CD44 protein and mRNA expression levels was inhibited by rapamycin. These findings suggest that hypoxia induced the proliferation and invasion of SGC-7901 and BGC-823 cells. Furthermore, CD44 expression levels were potentially associated with HIF-1α expression levels. Therefore, in gastric cancer cells, hypoxia may regulate CD44 expression via HIF-1α in order to promote cell proliferation and invasion.

Inhibition of histone/lysine acetyltransferase activity kills CoCl2-treated and hypoxia-exposed gastric cancer cells and reduces their invasiveness

Hypoxia enhances immortality and metastatic properties of solid tumors. Deregulation of histone acetylation has been associated with several metastatic cancers but its effect on hypoxic responses of cancer cells is not known. This study aimed at understanding the effectiveness of the hydrazinocurcumin, CTK7A, an inhibitor of p300 lysine/histone acetyltransferase (KAT/HAT) activity, in inducing apoptosis of gastric cancer cells (GCCs) exposed to cobalt chloride (CoCl₂), a hypoxia-mimetic chemical, or 1% O₂. Here, we show that CTK7A-induced hydrogen peroxide (H₂O₂) generation in CoCl₂-exposed and invasive gastric cancer cells (GCCs) leads to p38 MAPK-mediated Noxa expression and thereafter, mitochondrial apoptotic events. Noxa induction in normal immortalized gastric epithelial cells after CTK7A and hypoxia-exposure is remarkably less in comparison to similarly-treated GCCs. Moreover, hypoxia-exposed GCCs, which have acquired invasive properties, become apoptotic after CTK7A treatment to a significantly higher extent than normoxic cells. Thus, we show the potential of CTK7A in sensitizing hypoxic and metastatic GCCs to apoptosis induction.

The role of hypoxia in cancer progression, angiogenesis, metastasis, and resistance to therapy

Hypoxia is a non-physiological level of oxygen tension, a phenomenon common in a majority of malignant tumors. Tumor-hypoxia leads to advanced but dysfunctional vascularization and acquisition of epithelial-to-mesenchymal transition phenotype resulting in cell mobility and metastasis. Hypoxia alters cancer cell metabolism and contributes to therapy resistance by inducing cell quiescence. Hypoxia stimulates a complex cell signaling network in cancer cells, including the HIF, PI3K, MAPK, and NFĸB pathways, which interact with each other causing positive and negative feedback loops and enhancing or diminishing hypoxic effects. This review provides background knowledge on the role of tumor hypoxia and the role of the HIF cell signaling involved in tumor blood vessel formation, metastasis, and development of the resistance to therapy. Better understanding of the role of hypoxia in cancer progression will open new windows for the discovery of new therapeutics targeting hypoxic tumor cells and hypoxic microenvironment.

Bile acids destabilise HIF-1α and promote anti-tumour phenotypes in cancer cell models

Background

The role of the microbiome has become synonymous with human health and disease. Bile acids, as essential components of the microbiome, have gained sustained credibility as potential modulators of cancer progression in several disease models. At physiological concentrations, bile acids appear to influence cancer phenotypes, although conflicting data surrounds their precise physiological mechanism of action. Previously, we demonstrated bile acids destabilised the HIF-1α subunit of the Hypoxic-Inducible Factor-1 (HIF-1) transcription factor. HIF-1 overexpression is an early biomarker of tumour metastasis and is associated with tumour resistance to conventional therapies, and poor prognosis in a range of different cancers.

Methods

Here we investigated the effects of bile acids on the cancer growth and migratory potential of cell lines where HIF-1α is known to be active under hypoxic conditions. HIF-1α status was investigated in A-549 lung, DU-145 prostate and MCF-7 breast cancer cell lines exposed to bile acids (CDCA and DCA). Cell adhesion, invasion, migration was assessed in DU-145 cells while clonogenic growth was assessed in all cell lines.

Results

Intracellular HIF-1α was destabilised in the presence of bile acids in all cell lines tested. Bile acids were not cytotoxic but exhibited greatly reduced clonogenic potential in two out of three cell lines. In the migratory prostate cancer cell line DU-145, bile acids impaired cell adhesion, migration and invasion. CDCA and DCA destabilised HIF-1α in all cells and significantly suppressed key cancer progression associated phenotypes; clonogenic growth, invasion and migration in DU-145 cells.

Conclusions

These findings suggest previously unobserved roles for bile acids as physiologically relevant molecules targeting hypoxic tumour progression.

Annexin A1 sustains tumor metabolism and cellular proliferation upon stable loss of HIF1A

Despite the approval of numerous molecular targeted drugs, long-term antiproliferative efficacy is rarely achieved and therapy resistance remains a central obstacle of cancer care. Combined inhibition of multiple cancer-driving pathways promises to improve antiproliferative efficacy. HIF-1 is a driver of gastric cancer and considered to be an attractive target for therapy. We noted that gastric cancer cells are able to functionally compensate the stable loss of HIF-1α. Via transcriptomics we identified a group of upregulated genes in HIF-1α-deficient cells and hypothesized that these genes confer survival upon HIF-1α loss. Strikingly, simultaneous knock-down of HIF-1α and Annexin A1 (ANXA1), one of the identified genes, resulted in complete cessation of proliferation. Using stable isotope-resolved metabolomics, oxidative and reductive glutamine metabolism was found to be significantly impaired in HIF-1α/ANXA1-deficient cells, potentially explaining the proliferation defect. In summary, we present a conceptually novel application of stable gene inactivation enabling in-depth deconstruction of resistance mechanisms. In theory, this experimental approach is applicable to any cancer-driving gene or pathway and promises to identify various new targets for combination therapies.

Long-term Survival for Patients Undergoing Volatile versus IV Anesthesia for Cancer Surgery

Background

Surgical resection remains the best option for long-term survival in many solid tumors. Surgery can, however, lead to tumor cell release into the circulation. Data have suggested differential effects of anesthetic agents on cancer cell growth. This retrospective analysis investigated the association of anesthetic technique with long-term survival in patients presenting for elective surgery in a comprehensive cancer center over 3 yr.

Methods

All patients undergoing elective surgery between June 2010 and May 2013 were included. Patients were grouped according to whether they had received volatile inhalational (INHA) or total IV anesthesia (TIVA). After excluding those who received both forms of anesthesia during the study period, Kaplan–Meier survival curves were constructed from the date of surgery to death. After propensity matching, univariate and multivariable regression models were used to compare hazard ratios for death.

Results

A total of 11,395 anesthetics using INHA or TIVA were delivered in the study period. After exclusions, 3,316 patients (796 deaths, 24%) remained in the INHA group and 3,714 (504 deaths, 13.5%) in the TIVA group. After propensity matching, 2,607 patients remained in each group (597 deaths, 22.8%, in INHA group vs. 407, 15.6%, in TIVA group). Volatile inhalational anesthesia was associated with a hazard ratio of 1.59 (1.30 to 1.95) for death on univariate analysis and 1.46 (1.29 to 1.66) after multivariable analysis of known confounders in the matched group.

Conclusions

This retrospective analysis demonstrates an association between type of anesthetic delivered and survival. This analysis alongside biological plausibility should lead to urgent prospective work exploring the effect of anesthetic technique on survival.

The role of hypoxia in cancer progression, angiogenesis, metastasis, and resistance to therapy

Hypoxia is a non-physiological level of oxygen tension, a phenomenon common in a majority of malignant tumors. Tumor-hypoxia leads to advanced but dysfunctional vascularization and acquisition of epithelial-to-mesenchymal transition phenotype resulting in cell mobility and metastasis. Hypoxia alters cancer cell metabolism and contributes to therapy resistance by inducing cell quiescence. Hypoxia stimulates a complex cell signaling network in cancer cells, including the HIF, PI3K, MAPK, and NFĸB pathways, which interact with each other causing positive and negative feedback loops and enhancing or diminishing hypoxic effects. This review provides background knowledge on the role of tumor hypoxia and the role of the HIF cell signaling involved in tumor blood vessel formation, metastasis, and development of the resistance to therapy. Better understanding of the role of hypoxia in cancer progression will open new windows for the discovery of new therapeutics targeting hypoxic tumor cells and hypoxic microenvironment.

Peritoneal milky spots serve as a hypoxic niche and favor gastric cancer stem/progenitor cell peritoneal dissemination through hypoxia-inducible factor 1α

Peritoneal dissemination is the most common cause of death in gastric cancer patients. The hypoxic microenvironment plays a major role in controlling the tumor stem cell phenotype and is associated with patients' prognosis through hypoxia-inducible factor-1α (HIF-1α), a key transcriptional factor that responds to hypoxic stimuli. During the peritoneal dissemination process, gastric cancer stem/progenitor cells (GCSPCs) are thought to enter into and maintained in peritoneal milky spots (PMSs), which have hypoxic microenvironments. However, the mechanism through which the hypoxic environment of PMSs regulated GCSPC maintenance is still poorly understood. Here, we investigated whether hypoxic PMSs were an ideal cancer stem cell niche suitable for GCSPC engraftment. We also evaluated the mechanisms through which the HIF-1α-mediated hypoxic microenvironment regulated GCSPC fate. We observed a positive correlation between HIF-1α expression and gastric cancer peritoneal dissemination (GCPD) in gastric cancer patients. Furthermore, the GCSPC population expanded in primary gastric cancer cells under hypoxic condition in vitro, and hypoxic GCSPCs showed enhanced self-renewal ability, but reduced differentiation capacity, mediated by HIF-1α. In an animal model, GCSPCs preferentially resided in the hypoxic zone of PMSs; moreover, when the hypoxic microenvironment in PMSs was destroyed, GCPD was significantly alleviated. In conclusion, our results demonstrated that PMSs served as a hypoxic niche and favored GCSPCs peritoneal dissemination through HIF-1α both in vitro and in vivo. These results provided new insights into the GCPD process and may lead to advancements in the clinical treatment of gastric cancer.

Lentivirus-mediated RASSF1A expression suppresses aggressive phenotypes of gastric cancer cells in vitro and in vivo

Loss of Ras association domain family protein 1 isoform A (RASSF1A) expression is associated with the development of a variety of human cancers and the expression of carcinoembryonic antigen (CEA) frequently occurs in gastric cancer. This study investigated the effects of RASSF1A expression restoration using a hypoxia-inducible CEA promoter-driven vector on xenograft tumor growth in nude mice and on the in-vitro regulation of gastric cancer cell viability, cell cycle distribution, apoptosis, colony formation and invasion capacity. The data showed that the level of CEA mRNA and protein was much higher in gastric cancer SGC7901 cells than in a second gastric cancer cell line, MKN28, or in the MCF-10A normal epithelial breast cell line. RASSF1A expression was restored in SGC7901 cells compared with the negative control virus-infected SGC7910 cells. RASSF1A expression restoration significantly inhibited gastric cancer cell viability, colony formation and invasion capacity, but induced cell cycle arrest and apoptosis in vitro, especially under hypoxic culture conditions. At the gene level, restoration of RASSF1A expression under hypoxic culture conditions significantly suppressed matrix metalloproteinase-2 expression and prevented cyclinD1 expression. A nude mouse xenograft assay showed that the restoration of RASSF1A expression reduced gastric cancer xenograft formation and growth. In conclusion, the restoration of RASSF1A expression using a hypoxia-inducible and CEA promoter-driven vector suppressed aggressive phenotypes of gastric cancer cells in vitro and in vivo. These results suggest that LV-5HRE-CEAp-RASSF1A gene therapy may be a promising novel approach to treat advanced gastric cancer.

Targeting the bone marrow microenvironment in multiple myeloma

Multiple myeloma (MM) is characterized by clonal expansion of malignant plasma cells in the bone marrow (BM). Despite the significant advances in treatment, MM is still a fatal malignancy. This is mainly due to the supportive role of the BM microenvironment in differentiation, migration, proliferation, survival, and drug resistance of the malignant plasma cells. The BM microenvironment is composed of a cellular compartment (stromal cells, osteoblasts, osteoclasts, endothelial cells, and immune cells) and a non-cellular compartment. In this review, we discuss the interaction between the malignant plasma cell and the BM microenvironment and the strategy to target them.

Modulation of urokinase plasminogen activator system by poly(ADP-ribose)polymerase-1 inhibition

The urokinase plasminogen activator (uPA) system is a complex regulator of extracellular proteolysis which is involved in various physiological and pathological processes. The major components of this system are the serine protease uPA, two inhibitors PAI-1 and PAI-2, and the receptor uPAR. It has been previously shown by several groups that the uPA system has an important role in cancer progression and therefore its possible prognostic and therapeutic value has been evaluated. The aim of this study is to tackle the role of poly(ADP-ribosyl)ation in the induction of uPA activity in a glioblastoma cell line, A1235. This cell line is sensitive to alkylation damage and is a model for drug treatment. The components of the uPA system and the level of DNA damage were analyzed after alkylation agent treatment in combination with poly(ADP-ribose)polymerase-1 (PARP-1) inhibition. Here we show that the increase in uPA activity results from the net balance change between uPA and its inhibitor at mRNA level. Further, PARP-1 inhibition exerts its influence on uPA activity through DNA damage increase. Involvement of several signaling pathways, as well as cell specific regulation influencing the uPA system are discussed.

Application of two-dimensional gel-based mass spectrometry to functionally dissect resistance to targeted cancer therapy

PURPOSE

The majority of gastric cancers are diagnosed at advanced stages, characterized by robust therapy resistance. The oncoprotein hypoxia-inducible factor 1 (HIF-1) is associated with therapy resistance, partly via activation of the DNA damage response. We have noted a robust ability of gastric cancer cells to functionally compensate the loss of HIF-1 in vitro. The purpose of this study was to identify molecular pathways that underlie this compensation.

EXPERIMENTAL DESIGN

We performed 2DE to compare the nuclear proteome of wild-type and HIF-1-deficient gastric cancer cells. Differently expressed protein spots were identified via MS). After bioinformatic evaluation, functional validation of selected identified pathways was performed.

RESULTS

2DE displayed a total of 2523 protein spots, from which 87 were identified as regulated by HIF-1. Seventy of the identified spots were different proteins and 17 were isoforms. Bioinformatic analyses revealed that a significant amount of the identified proteins were related to cellular survival pathways. Specifically, members of the proteasome pathway were found upregulated upon loss of HIF-1. Combined inhibition of HIF-1 and the proteasome inflicted significant DNA damage, supporting the hypothesis that the proteasome is of functional importance to compensate the loss of HIF-1.

CONCLUSIONS AND CLINICAL RELEVANCE

Our data show robust and functional changes of the nuclear proteome upon inactivation of the HIF-1 oncoprotein in gastric cancer cells. We propose that 2DE-MS represents a useful tool to functionally dissect resistance mechanisms to targeted therapy and to identify novel targets for antiproliferative combination therapy.

Expression of monocyte chemotactic protein-1/CCL2 in gastric cancer and its relationship with tumor hypoxia

AIM: To investigate the expression and prognostic value of CCL2 in gastric cancer, as well as its relationship with tumor hypoxia.

METHODS: Tumor tissues from 68 gastric cancer patients (GC) were analyzed, and the expression of CCL2 and hypoxia-inducible factor 1 alpha (HIF-1α) in tumor tissues was detected by immunohistochemistry. Statistical evaluations that were used included univariate log-rank tests of Kaplan-Meier curves and multivariate Cox regression model analysis.

RESULTS: CCL2 was highly expressed in 66.2% (45/68) of gastric cancer specimens. The distribution of CCL2 expression in tumor tissue was consistent with that of HIF-1α. Patients with high CCL2 expression in GC had a lower overall survival rate [50.6 mo (95%CI: 44.44-56.93) vs 64.6 mo (95%CI: 60.27-68.94), P = 0.013].

CONCLUSION: CCL2 expression correlates closely with HIF-1α expression in gastric cancer. CCL2 may be an independent prognostic marker for GC.

Influence of different hypoxia models on metastatic potential of SGC-7901 gastric cancer cells

Gastric cancers are one of the most common gastrointestinal tumors with proclivity to metastasis. Hypoxia is an important feature in solid tumor microenvironment; accumulating evidence suggests that chronic and repetitive exposure to hypoxia and reoxygenation seems to provide an advantage to tumor growth. However, mechanisms of intermittent hypoxia regulating gastric cancer metastatic potential remain to be elucidated. In the present study, we established the continuous and intermittent gastric cancer hypoxia models, and we compared the effects of these models on gastric cancer cell metastatic potential. Hypoxia-inducible factor-1α (HIF-1α) and hypoxia target protein/genes expression in response to different hypoxia models were analyzed by Western blot, immunofluorescence, and real-time PCR assays. Gastric cancer cell migration and invasion ability were analyzed by wound healing and Boyden chamber assay. Colony formation and tumor spheroid formation assays were used to assess the ability of self-renewal. Stem-related protein OCT4 and HIF-1α expression were also analyzed by confocal immunofluorescence in single tertiary generation spheroid. We demonstrated that the intermittent hypoxia model upregulated expression of both HIF-1α and hypoxia target protein/genes in a time-dependent manner compared with that of SGC-7901 cells cultured under normoxia. Remarkably, HIF-1α protein was more prone to being located in the nucleus of SGC-7901 cells under conditions of intermittent hypoxia. Gastric cancer cells' migration and invasion ability were significantly enhanced after hypoxic culture; moreover, intermittent hypoxia-conditioned SGC-7901 cells exhibited higher invasiveness than the continuous hypoxia-conditioned SGC-7901 cells. Gastric cancer stem/progenitor cell subpopulation was also enlarged which indicated an enhanced self-renewal ability in hypoxic cultured SGC-7901 cells. Our study emphasizes the significance of hypoxia in regulating gastric cancer cell metastasis potential. Compared with continuous hypoxia, intermittent hypoxia is a more effective and potent hypoxic stimulus. These results provide a new insight to investigate the hypoxic microenvironment within solid tumors.

Role of the tumor microenvironment in the pathogenesis of gastric carcinoma

Gastric carcinoma (GC) is the 4^th most prevalent cancer and has the 2^nd highest cancer-related mortality rate worldwide. Despite the incidence of GC has decreased over the past few decades, it is still a serious health problem. Chronic inflammatory status of the stomach, caused by the infection of Helicobacter pylori (H. pylori) and through the production of inflammatory mediators within the parenchyma is suspected to play an important role in the initiation and progression of GC. In this review, the correlation between chronic inflammation and H. pylori infection as an important factor for the development of GC will be discussed. Major components, including tumor-associated macrophages, lymphocytes, cancer-associated fibroblasts, angiogenic factors, cytokines, and chemokines of GC microenvironment and their mechanism of action on signaling pathways will also be discussed. Increasing our understanding of how the components of the tumor microenviroment interact with GC cells and the signaling pathways involved could help identify new therapeutic and chemopreventive targets.