Microbiome Related Cytotoxically Active CD8+ TIL Are Inversely Associated With Lung Cancer Development

Toxicity assessment of Cucurbita pepo cv Dayangua and its effects on gut microbiota in mice

BACKGROUND

Cucurbita pepo cv Dayangua (CPD) is an edible plant with diverse pharmacological properties. The current research on CPD has primarily focused on initial investigations of its chemical composition and pharmacological effects, and no comprehensive toxicity assessment has been conducted to date.

METHODS

In the present study, the toxicity of CPD was evaluated through both acute and sub-chronic oral toxicity tests in mice. 16S rDNA sequencing was used to analyze the composition of the gut microbiota of mice at different time points to observe the effect of CPD on these microbial communities.

RESULTS

In the acute toxicity test, CPD exhibited low toxicity, with a median lethal dose (LD50) > 2000 mg/kg. The sub-chronic toxicity test indicated that CPD administration at doses of 200, 400, and 600 mg/kg did not cause mortality or significant organ damage in mice. Furthermore, analysis of the gut microbiota after gavage administration of CPD at 400 and 600 mg/kg revealed an improved abundance of some beneficial gut bacteria.

CONCLUSIONS

In summary, no acute or sub-chronic toxic effects were observed in mice following the oral administration of CPD. CPD did not affect the structure and diversity of the gut microbiota and may contribute to an increase in the number of beneficial gut bacteria.

Microbiome and cancer: from mechanistic implications in disease progression and treatment to development of novel antitumoral strategies

Cancer is a very aggressive disease and one of mankind's most important health problems, causing numerous deaths each year. Its etiology is complex, including genetic, gender-related, infectious diseases, dysbiosis, immunological imbalances, lifestyle, including dietary factors, pollution etc. Cancer patients also become immunosuppressed, frequently as side effects of chemotherapy and radiotherapy, and prone to infections, which further promote the proliferation of tumor cells. In recent decades, the role and importance of the microbiota in cancer has become a hot spot in human biology research, bringing together oncology and human microbiology. In addition to their roles in the etiology of different cancers, microorganisms interact with tumor cells and may be involved in modulating their response to treatment and in the toxicity of anti-tumor therapies. In this review, we present an update on the roles of microbiota in cancer with a focus on interference with anticancer treatments and anticancer potential.

Symbiotic microbial communities in various locations of the lung cancer respiratory tract along with potential host immunological processes affected

Lung cancer has the highest mortality rate among all cancers worldwide. The 5-year overall survival rate for non-small cell lung cancer (NSCLC) is estimated at around 26%, whereas for small cell lung cancer (SCLC), the survival rate is only approximately 7%. This disease places a significant financial and psychological burden on individuals worldwide. The symbiotic microbiota in the human body has been significantly associated with the occurrence, progression, and prognosis of various diseases, such as asthma, chronic obstructive pulmonary disease (COPD), and cystic fibrosis. Studies have demonstrated that respiratory symbiotic microorganisms and their metabolites play a crucial role in modulating immune function and contributing to the pathophysiology of lung cancer through their interactions with the host. In this review, we provide a comprehensive overview of the microbial characteristics associated with lung cancer, with a focus on the respiratory tract microbiota from different locations, including saliva, sputum, bronchoalveolar lavage fluid (BALF), bronchial brush samples, and tissue. We describe the respiratory tract microbiota's biodiversity characteristics by anatomical region, elucidating distinct pathological features, staging, metastasis, host chromosomal mutations, immune therapies, and the differentiated symbiotic microbiota under the influence of environmental factors. Our exploration investigates the intrinsic mechanisms linking the microbiota and its host. Furthermore, we have also provided a comprehensive review of the immune mechanisms by which microbiota are implicated in the development of lung cancer. Dysbiosis of the respiratory microbiota can promote or inhibit tumor progression through various mechanisms, including DNA damage and genomic instability, activation and regulation of the innate and adaptive immune systems, and stimulation of epithelial cells leading to the upregulation of carcinogenesis-related pathways.

Unique Changes in the Lung Microbiome following the Development of Chronic Lung Allograft Dysfunction

The importance of lung microbiome changes in developing chronic lung allograft dysfunction (CLAD) after lung transplantation is poorly understood. The lung microbiome-immune interaction may be critical in developing CLAD. In this context, examining alterations in the microbiome and immune cells of the lungs following CLAD, in comparison to the lung condition immediately after transplantation, can offer valuable insights. Four adult patients who underwent lung retransplantation between January 2019 and June 2020 were included in this study. Lung tissues were collected from the same four individuals at two different time points: at the time of the first transplant and at the time of the explantation of CLAD lungs at retransplantation due to CLAD. We analyzed whole-genome sequencing using the Kraken2 algorithm and quantified the cell fractionation from the bulk tissue gene expression profile for each lung tissue. Finally, we compared the differences in lung microbiome and immune cells between the lung tissues of these two time points. The median age of the recipients was 57 years, and most (75%) had undergone lung transplants for idiopathic pulmonary fibrosis. All patients were administered basiliximab for induction therapy and were maintained on three immunosuppressants. The median CLAD-free survival term was 693.5 days, and the median time to redo the lung transplant was 843.5 days. Bacterial diversity was significantly lower in the CLAD lungs than at transplantation. Bacterial diversity tended to decrease according to the severity of the CLAD. Aerococcus, Caldiericum, Croceibacter, Leptolyngbya, and Pulveribacter genera were uniquely identified in CLAD, whereas no taxa were identified in lungs at transplantation. In particular, six taxa, including Croceibacter atlanticus, Caldiserium exile, Dolichospermum compactum, Stappia sp. ES.058, Kinetoplastibacterium sorsogonicusi, and Pulveribacter suum were uniquely detected in CLAD. Among immune cells, CD8+ T cells were significantly increased, while neutrophils were decreased in the CLAD lung. In conclusion, unique changes in lung microbiome and immune cell composition were confirmed in lung tissue after CLAD compared to at transplantation.

Intratumoural microbiota: a new frontier in cancer development and therapy

Human microorganisms, including bacteria, fungi, and viruses, play key roles in several physiological and pathological processes. Some studies discovered that tumour tissues once considered sterile actually host a variety of microorganisms, which have been confirmed to be closely related to oncogenesis. The concept of intratumoural microbiota was subsequently proposed. Microbiota could colonise tumour tissues through mucosal destruction, adjacent tissue migration, and hematogenic invasion and affect the biological behaviour of tumours as an important part of the tumour microenvironment. Mechanistic studies have demonstrated that intratumoural microbiota potentially promote the initiation and progression of tumours by inducing genomic instability and mutations, affecting epigenetic modifications, promoting inflammation response, avoiding immune destruction, regulating metabolism, and activating invasion and metastasis. Since more comprehensive and profound insights about intratumoral microbiota are continuously emerging, new methods for the early diagnosis and prognostic assessment of cancer patients have been under examination. In addition, interventions based on intratumoural microbiota show great potential to open a new chapter in antitumour therapy, especially immunotherapy, although there are some inevitable challenges. Here, we aim to provide an extensive review of the concept, development history, potential sources, heterogeneity, and carcinogenic mechanisms of intratumoural microorganisms, explore the potential role of microorganisms in tumour prognosis, and discuss current antitumour treatment regimens that target intratumoural microorganisms and the research prospects and limitations in this field.

Non-immune cell components in tumor microenvironment influencing lung cancer Immunotherapy

Lung cancer (LC) is one of the leading causes of cancer-related deaths worldwide, with a significant morbidity and mortality rate, endangering human life and health. The introduction of immunotherapies has significantly altered existing cancer treatment strategies and is expected to improve immune responses, objective response rates, and survival rates. However, a better understanding of the complex immunological networks of LC is required to improve immunotherapy efficacy further. Tumor-associated antigens (TAAs) and tumor-specific antigens (TSAs) are significantly expressed by LC cells, which activate dendritic cells, initiate antigen presentation, and activate lymphocytes to exert antitumor activity. However, as tumor cells combat the immune system, an immunosuppressive microenvironment forms, enabling the enactment of a series of immunological escape mechanisms, including the recruitment of immunosuppressive cells and induction of T cell exhaustion to decrease the antitumor immune response. In addition to the direct effect of LC cells on immune cell function, the secreting various cytokines, chemokines, and exosomes, changes in the intratumoral microbiome and the function of cancer-associated fibroblasts and endothelial cells contribute to LC cell immune escape. Accordingly, combining various immunotherapies with other therapies can elicit synergistic effects based on the complex immune network, improving immunotherapy efficacy through multi-target action on the tumor microenvironment (TME). Hence, this review provides guidance for understanding the complex immune network in the TME and designing novel and effective immunotherapy strategies for LC.

Microbiota and lung cancer

Until recently, bacteria have been studied in terms of their roles in infectious diseases and mainly by using isolation and culture methods. However, in practice, many bacteria existing on the earth are difficult to isolate and culture, and thus only a limited number of them have been studied to date. On the other hand, in 2005, the next-generation sequencing technology became generally available, and since then genomic analysis of bacterial flora has become widespread. As a result, it has been revealed that the lower respiratory tract, which was previously thought to be sterile, in fact has bacterial flora (a microbiome) with a high level of biodiversity. In addition, it has been found that various diseases develop and worsen depending on the balance of the bacterial flora, and in recent years, a relationship has been established between various disorders. Recent research on cancer-associated microbial communities has elucidated the reciprocal interactions among bacteria, tumors and immune cells, the bacterial pathways associated with induction of oncogenesis, and their translational significance. Nevertheless, despite the increasing evidence showing that dysbiosis is associated with lung oncogenesis, the detailed mechanisms remain to be fully elucidated. Microorganisms seem to trigger tumor initiation and progression, presumably through the production of bacterio-toxins and other pro-inflammatory factors. The purpose of this review is to present a context for the basic mechanisms and molecular functions of the airway microbiome in oncogenesis, in an effort to prevent cancer by strategies utilizing the airway microbiota, as well as summarizing the mechanisms wherein the microbiome acts as a modulator of immunotherapies in lung cancer.

The Role of Respiratory Microbiota in Lung Cancer

Recently, the impact of microorganisms on tumor growth and metastasis has attracted great attention. The pathogenesis and progression of lung cancer are related to an increase in respiratory bacterial load as well as changes in the bacterial community because the microbiota affects tumors in many ways, including canceration, metastasis, angiogenesis, and treatment. The microbiota may increase tumor susceptibility by altering metabolism and immune responses, promoting inflammation, and increasing toxic effects. The microbiota can regulate tumor metastasis by altering multiple cell signaling pathways and participate in tumor angiogenesis through vascular endothelial growth factors (VEGF), endothelial cells (ECs), inflammatory factors and inflammatory cells. Tumor angiogenesis not only maintains tumor growth at the primary site but also promotes tumor metastasis and invasion. Therefore, angiogenesis is an important mediator of the interaction between microorganisms and tumors. The microbiota also plays a part in antitumor therapy. Alteration of the microbiota caused by antibiotics can regulate tumor growth and metastasis. Moreover, the microbiota also influences the efficacy and toxicity of tumor immunotherapy and chemotherapy. Finally, the effects of air pollution, a risk factor for lung cancer, on microorganisms and the possible role of respiratory microorganisms in the effects of air pollution on lung cancer are discussed.