scholarly journals Quantitative Visualization of Hypoxia and Proliferation Gradients Within Histological Tissue Sections

2019 ◽  
Author(s):  
Mark Zaidi ◽  
Fred Fu ◽  
Dan Cojocari ◽  
Trevor D. McKee ◽  
Bradly G. Wouters
Keyword(s):  
Molecular Mechanisms ◽  
Spatial Information ◽  
Radiation Treatment ◽  
Tumor Hypoxia ◽  
Chemotherapy Resistance ◽  
Cell Segmentation ◽  
Distance Analysis ◽  
Hypoxic Tolerance ◽  
Quantitative Visualization ◽  
Analysis Strategy

AbstractThe formation of hypoxic microenvironments within solid tumors is known to contribute to radiation resistance, chemotherapy resistance, immune suppression, increased metastasis, and an overall poor prognosis. It is therefore crucial to understand the spatial and molecular mechanisms that contribute to tumor hypoxia formation to improve the efficacy of radiation treatment, develop hypoxia-directed therapies, and increase patient survival. The objective of this study is to present a number of complementary novel methods for quantifying tumor hypoxia and proliferation, especially in relation to the location of perfused blood vessels.Multiplexed immunofluorescence staining can produce whole slide scanned image datasets that are amenable for computational pathology analysis. A standard marker analysis strategy is to take a positive pixel count approach, in which a threshold for positive stain is used to compute a positive area fraction for hypoxia. This work is a reassessment of that approach, utilizing not only cell segmentation but also distance to nearest blood vessel in order to incorporate spatial information into the analysis. We describe a reproducible pipeline for the visualization and quantitative analysis of hypoxia using a vessel distance analysis approach. This methodological pipeline can serve to further elucidate the relationship between vessel distance and microenvironment-linked markers such as hypoxia and proliferation, can help to quantify parameters relating to oxygen consumption and hypoxic tolerance in tissues, as well as potentially serve as a hypothesis generating tool for future studies testing hypoxia-linked markers.

Wnt/beta-catenin and PI3K/Akt/mTOR Signaling Pathways in Glioblastoma: Two Main Targets for Drug Design: A Review

2020 ◽  
Vol 26 (15) ◽  
pp. 1729-1741 ◽  
Author(s):  
Seyed H. Shahcheraghi ◽  
Venant Tchokonte-Nana ◽  
Marzieh Lotfi ◽  
Malihe Lotfi ◽  
Ahmad Ghorbani ◽  
...  
Keyword(s):  
Signaling Pathways ◽  
Molecular Mechanisms ◽  
Cellular Proliferation ◽  
Chemotherapy Resistance ◽  
Wnt Signaling Pathway ◽  
Therapeutic Interventions ◽  
Beta Catenin ◽  
Clinical Prognosis ◽  
Invasion And Migration ◽  
And Migration

: Glioblastoma (GBM) is the most common and malignant astrocytic glioma, accounting for about 90% of all brain tumors with poor prognosis. Despite recent advances in understanding molecular mechanisms of oncogenesis and the improved neuroimaging technologies, surgery, and adjuvant treatments, the clinical prognosis of patients with GBM remains persistently unfavorable. The signaling pathways and the regulation of growth factors of glioblastoma cells are very abnormal. The various signaling pathways have been suggested to be involved in cellular proliferation, invasion, and glioma metastasis. The Wnt signaling pathway with its pleiotropic functions in neurogenesis and stem cell proliferation is implicated in various human cancers, including glioma. In addition, the PI3K/Akt/mTOR pathway is closely related to growth, metabolism, survival, angiogenesis, autophagy, and chemotherapy resistance of GBM. Understanding the mechanisms of GBM’s invasion, represented by invasion and migration, is an important tool in designing effective therapeutic interventions. This review will investigate two main signaling pathways in GBM: PI3K/Akt/mTOR and Wnt/beta-catenin signaling pathways.

scholarly journals Chemotherapy Resistance Explained through Endoplasmic Reticulum Stress-Dependent Signaling

Cancers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 338 ◽  
Author(s):  
Entaz Bahar ◽  
Ji-Ye Kim ◽  
Hyonok Yoon
Keyword(s):  
Endoplasmic Reticulum ◽  
Er Stress ◽  
Molecular Mechanism ◽  
Molecular Mechanisms ◽  
Cellular Proliferation ◽  
Protein Quality ◽  
Chemotherapy Resistance ◽  
Persistent Problem ◽  
Stress Dependent ◽  
The Relationship

Cancers cells have the ability to develop chemotherapy resistance, which is a persistent problem during cancer treatment. Chemotherapy resistance develops through different molecular mechanisms, which lead to modification of the cancer cells signals needed for cellular proliferation or for stimulating an immune response. The endoplasmic reticulum (ER) is an important organelle involved in protein quality control, by promoting the correct folding of protein and ER-mediated degradation of unfolded or misfolded protein, namely, ER-associated degradation. Disturbances of the normal ER functions causes an accumulation of unfolded or misfolded proteins in the ER lumen, resulting in a condition called “ER stress (ERS).” ERS triggers the unfolded protein response (UPR)—also called the ERS response (ERSR)—to restore homeostasis or activate cell death. Although the ERSR is one emerging potential target for chemotherapeutics to treat cancer, it is also critical for chemotherapeutics resistance, as well. However, the detailed molecular mechanism of the relationship between the ERSR and tumor survival or drug resistance remains to be fully understood. In this review, we aim to describe the most vital molecular mechanism of the relationship between the ERSR and chemotherapy resistance. Moreover, the review also discusses the molecular mechanism of ER stress-mediated apoptosis on cancer treatments.

scholarly journals EBV encoded miRNA BART8-3p promotes radioresistance in nasopharyngeal carcinoma by regulating ATM/ATR signaling pathway

2019 ◽  
Vol 39 (9) ◽  
Author(s):  
Xiaohan Zhou ◽  
Jialing Zheng ◽  
Ying Tang ◽  
Yanling lin ◽  
Lingzhi Wang ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Signaling Pathway ◽  
Ataxia Telangiectasia ◽  
Molecular Mechanisms ◽  
Radiation Treatment ◽  
Ataxia Telangiectasia Mutated ◽  
Barr Virus ◽  
Radiotherapy Resistance

Abstract Resistance to radiotherapy is one of the main causes of treatment failure in patients with nasopharyngeal carcinoma (NPC). Epstein-Barr virus (EBV) infection is an important factor in the pathogenesis of NPC, and EBV-encoded microRNAs (miRNAs) promote NPC progression. However, the role of EBV-encoded miRNAs in the radiosensitivity of NPC remains unclear. Here, we investigated the effects of EBV-miR-BART8-3p on radiotherapy resistance in NPC cells in vitro and in vivo, and explored the underlying molecular mechanisms. Inhibitors of ataxia telangiectasia mutated (ATM)/ataxia telangiectasia mutated and Rad3-related (ATR) (KU60019 and AZD6738, respectively) were used to examine radiotherapy resistance. We proved that EBV-miR-BART8-3p promoted NPC cell proliferation in response to irradiation in vitro and associated with the induction of cell cycle arrest at the G2/M phase, which was a positive factor for the DNA repair after radiation treatment. Besides, EBV-miR-BART8-3p could increase the size of xenograft tumors significantly in nude mice. Treatment with KU60019 or AZD6738 increased the radiosensitivity of NPC by suppressing the expression of p-ATM and p-ATR. The present results indicate that EBV-miR-BART8-3p promotes radioresistance in NPC by modulating the activity of ATM/ATR signaling pathway.

scholarly journals Autophagy Facilitates Metadherin-Induced Chemotherapy Resistance Through the AMPK/ATG5 Pathway in Gastric Cancer

2018 ◽  
Vol 46 (2) ◽  
pp. 847-859 ◽  
Author(s):  
Guoqing Pei ◽  
Meng Luo ◽  
Xiaochun Ni ◽  
Jugang Wu ◽  
Shoulian Wang ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Drug Resistance ◽  
Molecular Mechanisms ◽  
Chemotherapy Resistance ◽  
Cell Counting ◽  
Cancer Resistance ◽  
Glycoprotein P ◽  
Real Time Quantitative Pcr ◽  
Mucosal Tissues ◽  
Underlying Mechanisms

Background/Aims: Metadherin (MTDH) is overexpressed in some malignancies and enhances drug resistance; however, its role in gastric cancer (GC) and the underlying mechanisms remain largely unexplored. Here, we explore the mechanism by which MTDH induces drug resistance in GC. Methods: We analysed the level of MTDH in GC and adjacent normal gastric mucosal tissues by real-time quantitative PCR (q-PCR). We also analysed the level of autophagy by western blot analysis, confocal microscopy, and transmission electron microscopy after MTDH knockdown and overexpression, and examined fluorouracil (5-FU) resistance by Cell Counting Kit-8 at the same time. Finally, GC patient-derived xenograft tumours were used to demonstrate 5-FU resistance. An AMPK pathway inhibitor was applied to determine the molecular mechanisms of autophagy. Results: MTDH expression was significantly increased in the GC specimens compared with that in the adjacent normal gastric mucosal tissues. Further study showed a positive correlation between the expression level of MTDH and 5-FU resistance. MTDH overexpression in MKN45 cells increased the levels of P-glycoprotein (P-gp) and promoted 5-FU resistance, while inhibition of MTDH showed the opposite result. The simultaneous inhibition of autophagy and overexpression of MTDH decreased the levels of P-gp and inhibited 5-FU resistance. Moreover, MTDH induced AMPK phosphorylation, regulated ATG5 expression, and finally influenced autophagy, suggesting that MTDH may activate autophagy via the AMPK/ATG5 signalling pathway. Our findings reveal a unique mechanism by which MTDH promotes GC chemoresistance and show that MTDH is a potential target for improved chemotherapeutic sensitivity and GC patient survival. Conclusions: MTDH-stimulated cancer resistance to 5-FU may be mediated through autophagy activated by the AMPK/ATG5 pathway in GC.

scholarly journals Different Heterotrimeric G Protein Dynamics for Wide-Range Chemotaxis in Eukaryotic Cells

2021 ◽  
Vol 9 ◽  
Author(s):  
Yoichiro Kamimura ◽  
Masahiro Ueda
Keyword(s):  
G Protein ◽  
Molecular Mechanisms ◽  
Spatial Information ◽  
Background Concentration ◽  
Gradient Sensing ◽  
Heterotrimeric G Protein ◽  
Gpcr Signaling ◽  
Chemical Gradients ◽  
Wide Range ◽  
Spatial Differences

Chemotaxis describes directional motility along ambient chemical gradients and has important roles in human physiology and pathology. Typical chemotactic cells, such as neutrophils and Dictyostelium cells, can detect spatial differences in chemical gradients over a background concentration of a 105 scale. Studies of Dictyostelium cells have elucidated the molecular mechanisms of gradient sensing involving G protein coupled receptor (GPCR) signaling. GPCR transduces spatial information through its cognate heterotrimeric G protein as a guanine nucleotide change factor (GEF). More recently, studies have revealed unconventional regulation of heterotrimeric G protein in the gradient sensing. In this review, we explain how multiple mechanisms of GPCR signaling ensure the broad range sensing of chemical gradients in Dictyostelium cells as a model for eukaryotic chemotaxis.

scholarly journals Molecular Mechanisms of Chemotherapy Resistance in Head and Neck Cancers

2021 ◽  
Vol 11 ◽  
Author(s):  
Yuzuka Kanno ◽  
Chang-Yu Chen ◽  
Hsin-Lun Lee ◽  
Jeng-Fong Chiou ◽  
Yin-Ju Chen
Keyword(s):  
Head And Neck ◽  
Molecular Mechanisms ◽  
Chemotherapy Resistance ◽  
Growth Factor Receptor ◽  
Nuclear Factor Κb ◽  
Cancer Treatments ◽  
Effective Strategies ◽  
Damage Repair ◽  
Apoptosis Inhibition ◽  
Epidermal Growth

Chemotherapy resistance is a huge barrier for head and neck cancer (HNC) patients and therefore requires close attention to understand its underlay mechanisms for effective strategies. In this review, we first summarize the molecular mechanisms of chemotherapy resistance that occur during the treatment with cisplatin, 5-fluorouracil, and docetaxel/paclitaxel, including DNA/RNA damage repair, drug efflux, apoptosis inhibition, and epidermal growth factor receptor/focal adhesion kinase/nuclear factor-κB activation. Next, we describe the potential approaches to combining conventional therapies with previous cancer treatments such as immunotherapy, which may improve the treatment outcomes and prolong the survival of HNC patients. Overall, by parsing the reported molecular mechanisms of chemotherapy resistance within HNC patient’s tumors, we can improve the prediction of chemotherapeutic responsiveness, and reveal new therapeutic targets for the future.

scholarly journals The Role of Autophagy in Gastric Cancer Chemoresistance: Friend or Foe?

2020 ◽  
Vol 8 ◽  
Author(s):  
Jing-Li Xu ◽  
Li Yuan ◽  
Yan-Cheng Tang ◽  
Zhi-Yuan Xu ◽  
Han-Dong Xu ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Drug Resistance ◽  
Molecular Mechanisms ◽  
Chemotherapy Resistance ◽  
Dual Roles ◽  
Non Coding Rnas ◽  
Regulatory Effects ◽  
Cancer Chemoresistance ◽  
The Relationship

Gastric cancer is the third most common cause of cancer-related death worldwide. Drug resistance is the main inevitable and vital factor leading to a low 5-year survival rate for patients with gastric cancer. Autophagy, as a highly conserved homeostatic pathway, is mainly regulated by different proteins and non-coding RNAs (ncRNAs) and plays dual roles in drug resistance of gastric cancer. Thus, targeting key regulatory nodes in the process of autophagy by small molecule inhibitors or activators has become one of the most promising strategies for the treatment of gastric cancer in recent years. In this review, we provide a systematic summary focusing on the relationship between autophagy and chemotherapy resistance in gastric cancer. We comprehensively discuss the roles and molecular mechanisms of multiple proteins and the emerging ncRNAs including miRNAs and lncRNAs in the regulation of autophagy pathways and gastric cancer chemoresistance. We also summarize the regulatory effects of autophagy inhibitor and activators on gastric cancer chemoresistance. Understanding the vital roles of autophagy in gastric cancer chemoresistance will provide novel opportunities to develop promising therapeutic strategies for gastric cancer.

Sign in / Sign up

Export Citation Format

Share Document