Gene expression in tumor cells and stroma in dsRed 4T1 tumors in eGFP-expressing mice with and without enhanced oxygenation

Bioluminescence - The Vibrant Glow of Nature and its Chemical Mechanisms

Bioluminescence, the mesmerizing natural phenomenon where living organisms produce light through chemical reactions, has long captivated scientists and laypersons alike, offering a rich tapestry of insights into biological function, ecology, evolution as well as the underlying chemistry. This comprehensive introductory review systematically explores the phenomenon of bioluminescence, addressing its historical context, geographic dispersion, and ecological significance with a focus on their chemical mechanisms. Our examination begins with terrestrial bioluminescence, discussing organisms from different habitats. We analyze thefireflies of Central Europe's meadows and the fungi in the Atlantic rainforest of Brazil. Additionally, we inspect bioluminescent species in New Zealand, specifically river-dwelling snails and mosquito larvae found in Waitomo Caves. Our exploration concludes in the Siberian Steppes, highlighting the area's luminescent insects and annelids. Transitioning to the marine realm, the second part of this review examines marine bioluminescent organisms. We explore this phenomenon in deep-sea jellyfish and their role in the ecosystem. We then move to Toyama Bay, Japan, where seasonal bioluminescence of dinoflagellates and ostracods present a unique case study. We also delve into the bacterial world, discussing how bioluminescent bacteria contribute to symbiotic relationships. For each organism, we contextualize its bioluminescence, providing details about its discovery, ecological function, and geographical distribution. A special focus lies on the examination of the underlying chemical mechanisms that enables these biological light displays. Concluding this review, we present a series of practical bioluminescence and chemiluminescence experiments, providing a resource for educational demonstrations and student research projects. Our goal with this review is to provide a summary of bioluminescence across the diverse ecological contexts, contributing to the broader understanding of this unique biological phenomenon and its chemical mechanisms serving researchers new to the field, educators and students alike.

HBO regulates the Warburg effect of hypoxic HCC cells through miR-103a-3p/TRIM35

BACKGROUND

There are a lot of studies on the treatment of tumors with hyperbaric oxygen, while most of them are in breast cancer, prostate cancer and so on. However, there are still few studies on hyperbaric oxygen in treating hepatocellular carcinoma (HCC). According to the current data, hyperbaric oxygen is an effective means to intervene in tumors. The Warburg effect is a unique marker of glucose metabolism in tumors related to hypoxia, making it possible for hyperbaric oxygen to interfere with the tumor through the Warburg effect.

METHOD

We used the hypoxia/hyperbaric oxygen(HBO)-exposed HCC cells for in vitro studies. Glucose uptake, lactic acid, and adenosine triphosphate (ATP) assessed the Warburg effect. The expression of miR-103a-3p in HCC was detected by using qRT-PCR. The effect of miR-103a-3p/TRIM35 expression level on the cells was measured using the CCK8 method and flow cytometry. The molecular biological mechanism of miR-103a-3p in HCC was examined using the luciferase reporter, MS2-RIP assays.

RESULT

HBO inhibited the Warburg effect in hypoxic HCC cells. HBO suppressed the expression of miR-103a-3p in hypoxic HCC cells, and miR-103a-3p inhibited the expression of TRIM35 in hypoxic HCC cells. With HBO exposure, miR-103a-3p/TRIM35 regulated the Warburg effect of hypoxic HCC cells.

CONCLUSION

These findings reveal that HBO regulates the Warburg effect of hypoxic HCC cells through miR-103a-3p/TRIM35 and inhibits tumor growth.

Advances in hyperbaric oxygen to promote immunotherapy through modulation of the tumor microenvironment

Hyperbaric oxygen therapy is a relatively safe treatment method that has been used for a long time in the clinic. It has been proven that it can enhance the sensitivity of radiotherapy and photodynamic therapy for cancer. However, there are few studies on hyperbaric oxygen and immunotherapy. In this article, we summarize that hyperbaric oxygen therapy regulates the tumor microenvironment through various pathways such as improving tumor hypoxia, targeting hypoxia-inducing factors, and generating reactive oxygen species. The change in the tumor microenvironment ultimately affects the curative effect of immunotherapy. Therefore, hyperbaric oxygen can influence immunotherapy by regulating the tumor microenvironment, providing a direction for the future development of immunotherapy.

Fibroblasts as Turned Agents in Cancer Progression

Differentiated epithelial cells reside in the homeostatic microenvironment of the native organ stroma. The stroma supports their normal function, their G0 differentiated state, and their expansion/contraction through the various stages of the life cycle and physiologic functions of the host. When malignant transformation begins, the microenvironment tries to suppress and eliminate the transformed cells, while cancer cells, in turn, try to resist these suppressive efforts. The tumor microenvironment encompasses a large variety of cell types recruited by the tumor to perform different functions, among which fibroblasts are the most abundant. The dynamics of the mutual relationship change as the sides undertake an epic battle for control of the other. In the process, the cancer "wounds" the microenvironment through a variety of mechanisms and attracts distant mesenchymal stem cells to change their function from one attempting to suppress the cancer, to one that supports its growth, survival, and metastasis. Analogous reciprocal interactions occur as well between disseminated cancer cells and the metastatic microenvironment, where the microenvironment attempts to eliminate cancer cells or suppress their proliferation. However, the altered microenvironmental cells acquire novel characteristics that support malignant progression. Investigations have attempted to use these traits as targets of novel therapeutic approaches.

Hypoxia signaling in cancer: Implications for therapeutic interventions

Hypoxia is a persistent physiological feature of many different solid tumors and a key driver of malignancy, and in recent years, it has been recognized as an important target for cancer therapy. Hypoxia occurs in the majority of solid tumors due to a poor vascular oxygen supply that is not sufficient to meet the needs of rapidly proliferating cancer cells. A hypoxic tumor microenvironment (TME) can reduce the effectiveness of other tumor therapies, such as radiotherapy, chemotherapy, and immunotherapy. In this review, we discuss the critical role of hypoxia in tumor development, including tumor metabolism, tumor immunity, and tumor angiogenesis. The treatment methods for hypoxic TME are summarized, including hypoxia-targeted therapy and improving oxygenation by alleviating tumor hypoxia itself. Hyperoxia therapy can be used to improve tissue oxygen partial pressure and relieve tumor hypoxia. We focus on the underlying mechanisms of hyperoxia and their impact on current cancer therapies and discuss the prospects of hyperoxia therapy in cancer treatment.

Melatonin and hyperbaric oxygen therapies suppress colorectal carcinogenesis through pleiotropic effects and multifaceted mechanisms

Colorectal cancer (CRC) is the third most common cancer worldwide. Colorectal carcinogenesis is frequently induced by hypoxia to trigger the reprogramming of cellular metabolism and gain of malignant phenotypes. Previously, hyperbaric oxygen (HBO) therapy and melatonin have been reported to alter the hypoxic microenvironment, resulting in inhibiting cancer cell survival. Accordingly, this study tested the hypothesis whether HBO and melatonin effectively inhibited CRC carcinogenesis. In vitro results indicated that melatonin therapy significantly suppressed the malignant phenotypes, including colony formation, growth, invasion, migration and cancer stemness with dose-dependent manners in CRC cell lines through multifaceted mechanisms. Similar to in vitro study, in vivo findings further demonstrated the melatonin, HBO and combined treatments effectively promoted apoptosis (cleaved-caspase 3/ cleaved-PARP) and arrested tumor proliferation, followed by inhibiting colorectal tumorigenesis in CRC xenograft tumor model. Moreover, melatonin, HBO and combined treatments modulated multifaceted mechanisms, including decreasing HIF-1α expression, alleviating AKT activation, repressing glycolytic metabolism (HK-2/PFK1/PKM2/LDH), restraining cancer stemness pathway (TGF-β/p-Smad3/Oct4/Nanog), reducing inflammation (p-NFκB/ COX-2), diminishing immune escape (PD-L1), and reversing expression of epithelial mesenchymal transition (E-cadherin/N-cadherin/MMP9). In conclusion, melatonin and HBO therapies suppressed colorectal carcinogenesis through the pleiotropic effects and multifaceted mechanisms, suggesting melatonin and HBO treatments could be novel therapeutic strategies for CRC treatment.

[Peripheral blood exosomes from patients with multiple myeloma mediate bortezomib resistance in cultured multiple myeloma cells]

OBJECTIVE

To investigate the role of exosome in mediating bortezomib (Btz) resistance in multiple myeloma cells in vitro and explore the underlying mechanisms.

METHODS

Peripheral blood samples were collected from 15 patients with multiple myeloma with Btz tolerance, and serum exosomes were isolated by ultracentrifugation and identified with electron microscopy, NTA and Western blotting. In vitro cultured multiple myeloma cells were treated with gradient concentrations of Btz to determine the optimal drug concentration for subsequent experiment. The cells were pretreated with different concentrations of exosomes, and their sensitivity to BTZ was assessed using MTS assay. We searched the exosome database Exocarta and used STRING to generate the network map and the protein interaction graph.

RESULTS

The diameters of the vesicles isolated from the peripheral blood of the patients were mostly below 200 nm with a mean particle size of 153 nm and a mode of 140.1 nm. The results of Western blotting showed that the isolated exosomes expressed the marker proteins CD63, Tsg101 and Alix. In cultured multiple myeloma cells, pretreatment with exosomes resulted in a decreased sensitivity of the cells to bortezomib, and longer treatment durations and higher exosome concentrations consistently enhanced the resistance of the cells to the same Btz concentration. Analysis of the Exocarta database identified human serum exosomal proteins ABCB1, ABCB4, PDCD6IP, and EGFR, among which EGFR served as a network node.

CONCLUSIONS

Exosome within a specific concentration range may serve as a signal carrier to mediate the resistance of multiple myeloma cells to Btz. EGFR likely plays a key role to promote exosome-mediated Btz resistance in myeloma cells.

Protein expression profiling of plasma and lungs at different stages of metastatic development in a human triple negative breast cancer xenograft model

The main objective of this study was to identify single proteins or protein networks that might be used as diagnostic biomarkers or for therapeutic purposes by evaluating the protein expression profiling of plasma and lungs at different stages of metastatic development in a human triple negative MDA-MB-231 breast cancer xenograft model. MDA-MB-231 tumour cells were injected into the mammary fat pads on one side of the groin area. The mice were sacrificed day 19 (pre-metastases) and day 54 (metastases). Non-injected mice served as controls. Plasma was collected and lungs harvested for both immunohistochemistry and protein analysis. The most striking observation in plasma was the initial reduction in haptoglobin level at the pre-metastatic stage, to a following significant increase in haptoglobin level at the metastatic stage, with a more than 4000-fold increase from the pre-metastatic to the metastatic phase. A corresponding increase in haptoglobin level was also found in lung tissue after metastasis. Fibrinogen beta chain also had a similar change in expression level in plasma as haptoglobin, however not as prominent. There were also changes in plasma thrombospondin-4 and transferrin receptor protein 1 levels, from an increase at the pre-metastatic stage, to a significant fall when metastases were established. This suggests that especially changes in haptoglobin, but also fibrinogen beta chain, thrombospondin-4 and transferrin receptor protein 1 is indicative of metastasis, at least in this breast cancer model, and should be further evaluated as general breast cancer biomarkers.

Strategic labelling approaches for RNA single-molecule spectroscopy

Most single-molecule techniques observing RNA in vitro or in vivo require fluorescent labels that have to be connected to the RNA of interest. In recent years, a plethora of methods has been developed to achieve site-specific labelling, in many cases under near-native conditions. Here, we review chemical as well as enzymatic labelling methods that are compatible with single-molecule fluorescence spectroscopy or microscopy and show how these can be combined to offer a large variety of options to site-specifically place one or more labels in an RNA of interest. By either chemically forming a covalent bond or non-covalent hybridization, these techniques are prerequisites to perform state-of-the-art single-molecule experiments.

Oxygen-dependent regulation of tumor growth and metastasis in human breast cancer xenografts

Background

Tumor hypoxia is relevant for tumor growth, metabolism, resistance to chemotherapy and metastasis. We have previously shown that hyperoxia, using hyperbaric oxygen treatment (HBOT), attenuates tumor growth and shifts the phenotype from mesenchymal to epithelial (MET) in the DMBA-induced mammary tumor model. This study describes the effect of HBOT on tumor growth, angiogenesis, chemotherapy efficacy and metastasis in a triple negative MDA-MB-231 breast cancer model, and evaluates tumor growth using a triple positive BT-474 breast cancer model.

Materials and methods

5 x 10⁵ cancer cells were injected s.c. in the groin area of NOD/SCID female mice. The BT-474 group was supplied with Progesterone and Estradiol pellets 2-days prior to tumor cell injection. Mice were divided into controls (1 bar, pO₂ = 0.2 bar) or HBOT (2.5 bar, pO₂ = 2.5 bar, 90 min, every third day until termination of the experiments). Treatment effects were determined by assessment of tumor growth, proliferation (Ki67-staining), angiogenesis (CD31-staining), metastasis (immunostaining), EMT markers (western blot), stromal components collagen type I, Itgb1 and FSP1 (immunostaining) and chemotherapeutic efficacy (5FU).

Results

HBOT significantly suppressed tumor growth in both the triple positive and negative tumors, and both MDA-MB-231 and BT-474 showed a decrease in proliferation after HBOT. No differences were found in angiogenesis or 5FU efficacy between HBOT and controls. Nevertheless, HBOT significantly reduced both numbers and total area of the metastastatic lesions, as well as reduced expression of N-cadherin, Axl and collagen type I measured in the MDA-MB-231 model. No change in stromal Itgb1 and FSP1 was found in either tumor model.

Conclusion

Despite the fact that behavior and prognosis of the triple positive and negative subtypes of cancer are different, the HBOT had a similar suppressive effect on tumor growth, indicating that they share a common oxygen dependent anti-tumor mechanism. Furthermore, HBOT significantly reduced the number and area of metastatic lesions in the triple negative model as well as a significant reduction in the EMT markers N-cadherin, Axl and density of collagen type I.

Hyperbaric oxygen promotes malignant glioma cell growth and inhibits cell apoptosis

Glioblastoma multiforme (GBM) is the most frequently diagnosed intracranial malignant tumor in adults. Clinical studies have indicated that hyperbaric oxygen may improve the prognosis and reduce complications in glioma patients; however, the specific mechanism by which this occurs remains unknown. The present study investigated the direct effects of hyperbaric oxygen stimulation on glioma by constructing an intracranial transplanted glioma model in congenic C57BL/6J mice. Bioluminescent imaging (BLI) was used to assess the growth of intracranial transplanted GL261-Luc glioma cells in vivo, while flow cytometric and immunohistochemical assays were used to detect and compare the expression of the biomarkers, Ki-67, CD34 and TUNEL, reflecting the cell cycle, apoptosis and angiogenesis. BLI demonstrated that hyperbaric oxygen promoted the growth of intracranially transplanted GL261-Luc glioma cells in vivo. Flow cytometric analysis indicated that hyperbaric oxygen promoted GL261-Luc glioma cell proliferation and also prevented cell cycle arrest. In addition, hyperbaric oxygen inhibited the apoptosis of the transplanted glioma cells. Immunohistochemical analysis also indicated that hyperbaric oxygen increased positive staining for Ki-67 and CD34, while reducing staining for TUNEL (a marker of apoptosis). The microvessel density was significantly increased in the hyperbaric oxygen treatment group compared with the control group. In conclusion, hyperbaric oxygen treatment promoted the growth of transplanted malignant glioma cells in vivo and also inhibited the apoptosis of these cells.

A red fluorescent protein (DsRED) from Discosoma sp. as a reporter for gene expression in walnut somatic embryos

KEY MESSAGE

An improved scorable marker was developed for somatic embryo transformation. This method is more reliable than GFP and provides more efficient embryo selection than β-glucuronidase assays (GUS, MUG). Reporter genes are widely used to select transformed cells and tissues. Fluorescent proteins have become an integral part of live-cell imaging research over the past 10 years. DsRED is an ideal reporter for avoiding plant chlorophyll autofluorescence and for double labeling in combination with other scorable markers. In this study, we transformed walnut somatic embryos with a construct containing the DsRED-expressing binary vector pKGW-RR to assess the effect of this red fluorescent protein visual reporter on both embryos and regenerated plants. Results showed that DsRED expression was apparent with maximum brightness at 7-10 days after initiation. Fourteen of twenty-four surviving somatic embryos were bright red. These E0 embryos generated 25 wholly fluorescent E1 embryos and 43 wholly fluorescent E2 embryos at 2 weeks intervals. The germination percentage of DsRED-positive embryos was greater than 80% and gave rise to 45 fluorescent transgenic walnut plants. The regenerated transgenic plants expressed DsRED in all tissues examined including transverse sections of vegetative organs. The percentage of transformed plants that developed roots (48.3%) was similar to control shoots (53%). For transformation of walnut somatic embryos, the DsRED-based reporter system is more stable and reliable than green fluorescent protein (GFP) and, since it is a directly read and non-destructive assay, it provides a more efficient means of monitoring transformation than β-glucuronidase (GUS).

A novel GFP nude rat model to investigate tumor-stroma interactions

BACKGROUD

A key strategy for the study of the tumor microenvironment is to implant human tumor cells in an immunodeficient rodent strain ubiquitously expressing a fluorescent marker. Here, a novel nude rat expressing a green fluorescent protein (GFP) transgene was established and engrafted with primary human tumor tissue in order to separate tumor from stromal cell populations for subsequent molecular analysis.

METHODS

SD-TG (GFP) 2BalRrrc transgenic rats were crossed with HsdHan™: rnu/rnu Rowett nude rats to develop a GFP expressing immunocompromised rat. PCR and flow cytometry were used to follow the GFP genotype and phenotype in newborns. After three to four generations, animals were implanted with 4 T1 dsRed murine breast cancer cells or primary human glioblastoma (GBM) biopsies to generate xenografts for subsequent separation by fluorescence-activated cell sorting (FACS).

RESULTS

Fluorecence microscopy and reverse transcription-PCR demonstrated that GFP, under the control of the human ubiquitin C promoter, was stably maintained and expressed in diverse organs over several generations. Immunophenotyping of blood samples by flow cytometry confirmed that the immunodeficient features of the parental rat strain, HsdHan™: rnu/rnu, were retained in the GFP nude rat. Both the murine cell line and human GBM biopsies engrafted, and stromal cell populations were isolated from dissociated xenografts by FACS to > 95% purity.

CONCLUSIONS

A GFP transgene was stably introduced into a nude rat background in which human and murine cancer cells successfully engrafted. This animal strain provides a novel in vivo system for detailed cellular and molecular characterization of tumor-stroma interactions.

Hyperbaric oxygen therapy and cancer--a review

Hypoxia is a critical hallmark of solid tumors and involves enhanced cell survival, angiogenesis, glycolytic metabolism, and metastasis. Hyperbaric oxygen (HBO) treatment has for centuries been used to improve or cure disorders involving hypoxia and ischemia, by enhancing the amount of dissolved oxygen in the plasma and thereby increasing O₂ delivery to the tissue. Studies on HBO and cancer have up to recently focused on whether enhanced oxygen acts as a cancer promoter or not. As oxygen is believed to be required for all the major processes of wound healing, one feared that the effects of HBO would be applicable to cancer tissue as well and promote cancer growth. Furthermore, one also feared that exposing patients who had been treated for cancer, to HBO, would lead to recurrence. Nevertheless, two systematic reviews on HBO and cancer have concluded that the use of HBO in patients with malignancies is considered safe. To supplement the previous reviews, we have summarized the work performed on HBO and cancer in the period 2004–2012. Based on the present as well as previous reviews, there is no evidence indicating that HBO neither acts as a stimulator of tumor growth nor as an enhancer of recurrence. On the other hand, there is evidence that implies that HBO might have tumor-inhibitory effects in certain cancer subtypes, and we thus strongly believe that we need to expand our knowledge on the effect and the mechanisms behind tumor oxygenation.