The Role of Inflammation in Breast and Prostate Cancer Metastasis to Bone

Identification of the cytoplasmic DNA-Sensing cGAS-STING pathway-mediated gene signatures and molecular subtypes in prostate cancer

BACKGROUND

Considering the age relevance of prostate cancer (PCa) and the involvement of the cGAS-STING pathway in aging and cancer, we aim to classify PCa into distinct molecular subtypes and identify key genes from the novel perspective of the cGAS-STING pathway. It is of significance to guide personalized intervention of cancer-targeting therapy based on genetic evidence.

METHODS

The 430 patients with PCa from the TCGA database were included. We integrated 29 key genes involved in cGAS-STING pathway and analyzed differentially expressed genes and biochemical recurrence (BCR)-free survival-related genes. The assessments of tumor stemness and heterogeneity and tumor microenvironment (TME) were conducted to reveal potential mechanisms.

RESULTS

PCa patients were classified into two distinct subtypes using AURKB, TREX1, and STAT6, and subtype 1 had a worse prognosis than subtype 2 (HR: 21.19, p < 0.001). The findings were validated in the MSKCC2010 cohort. Among subtype 1 and subtype 2, the top ten mutation genes were MUC5B, DNAH9, SLC5A10, ZNF462, USP31, SIPA1L3, PLEC, HRAS, MYOM1, and ITGB6. Gene set variation analysis revealed a high enrichment of the E2F target in subtype 1, and gene set enrichment analysis showed significant enrichment of base excision repair, cell cycle, and DNA replication in subtype 1. TME evaluation indicated that subtype 1 had a significantly higher level of T cells follicular helper and a lower level of plasma cells than subtype 2.

CONCLUSIONS

The molecular subtypes mediated by the cGAS-STING pathway and the genetic risk score may aid in identifying potentially high-risk PCa patients who may benefit from pharmacologic therapies targeting the cGAS-STING pathway.

Prognostic and therapeutic potential of senescent stromal fibroblasts in prostate cancer

The stromal component of the tumour microenvironment in primary and metastatic prostate cancer can influence and promote disease progression. Within the prostatic stroma, fibroblasts are one of the most prevalent cell types associated with precancerous and cancerous lesions; they have a vital role in the structural composition, organization and integrity of the extracellular matrix. Fibroblasts within the tumour microenvironment can undergo cellular senescence, which is a stable arrest of cell growth and a phenomenon that is emerging as a recognized hallmark of cancer. Supporting the idea that cellular senescence has a pro-tumorigenic role, a subset of senescent cells exhibits a senescence-associated secretory phenotype (SASP), which, along with increased inflammation, can promote prostate cancer cell growth and survival. These cellular characteristics make targeting senescent cells and/or modulating SASP attractive as a potential preventive or therapeutic option for prostate cancer.

Association between monocyte-to-lymphocyte ratio and prostate cancer in the U.S. population: a population-based study

Introduction

Monocyte-to-lymphocyte ratio (MLR) is a convenient and noninvasive inflammatory biomarker, and inflammation has been reported to be associated with prostate cancer (PCa). Our objective was to ascertain any possible correlation between PCa and MLR.

Methods

We utilized data from the 1999-2020 cycles of the National Health and Nutrition Examination Survey (NHANES) regarding MLR and PCa. The independent associations of MLR and other inflammatory biomarkers (platelet-to-lymphocyte ratio (PLR), systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), system inflammation response index (SIRI), and aggregate index of systemic inflammation (AISI)) with PCa was investigated using weighted multivariate logistic regression and generalized additive models. Receiver operating characteristic (ROC) curves were conducted to evaluate and contrast their diagnostic capabilities.

Results

The analysis we conducted comprised 25,367 persons in total. The mean MLR was 0.31 ± 0.14. The prevalence of PCa was 3.1%. A positive association was found between MLR and PCa (OR = 2.28; 95% CI: 1.44, 3.62). According to the interaction tests, age, body mass index (BMI), hypertension, diabetes, and smoking status did not significantly impact the relationship between MLR and PCa (all p for interaction >0.05). ROC analysis showed that MLR had a stronger discriminative ability and accuracy in predicting PCa than other inflammatory biomarkers (NLR, SII, AISI, PLR, and SIRI).

Conclusion

MLR might be better than other inflammatory biomarkers (NLR, SIRI, AISI, PLR, and SII) in predicting PCa. American adults who have elevated levels of MLR, NLR, PLR, SII, and AISI should be aware that they have a greater risk of PCa.

The prognostic value of absolute lymphocyte count and neutrophil-to-lymphocyte ratio for patients with metastatic breast cancer: a systematic review and meta-analysis

Background

Neutrophil-to-lymphocyte ratio (NLR) is considered a potential prognostic marker in early breast cancer. However, the prognosis of absolute lymphocyte count (ALC) and NLR in metastatic breast cancer (MBC) has been reported in a few studies, and conclusions are still conflicting. This present manuscript aims to provide further solid evidence regarding the prognostic values of ALC and NLR in MBC patients.

Method

Eligible studies that reported the associations between ALC or NLR and MBC were included by searching relative electronic databases. Overall survival (OS) and progression-free survival (PFS) were used as outcome measures. The hazard ratio (HR) values and 95% confidence interval (CI) of the outcome measures were collected as effect sizes, and further analysis and discussion were conducted according to the pooled HR, subgroup analysis, publication bias, and interstudy heterogeneity.

Results

Twenty-nine studies comprising 3,973 patients with MBC were included. According to our findings, lower ALC was significantly associated with poorer prognosis of OS (HR = 0.57, 95% CI 0.48 to 0.68) and PFS (HR = 0.68, 95% CI 0.58 to 0.79), and greater NLR was associated with poorer OS (HR = 1.50, 95% CI 1.35 to 1.67) and PFS (HR = 1.82, 95% CI 1.42 to 2.35). Furthermore, the prognostic values of ALC and NLR in MBC were also observed in the subgroup analyses regarding cutoff values and ethnicities.

Conclusion

Low ALC and elevated NLR were observed to be significantly associated with adverse OS and PFS in MBC, indicating that ALC and NLR may act as potential prognostic biomarkers of MBC patients. Meanwhile, our results will also provide some novel evidence and research clues for the selection and development of clinical treatment strategies for MBC patients.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42021224114.

Can the Epstein-Barr Virus Play a Role in the Development of Prostate Cancer?

Prostate cancer (PCa) is the fourth most frequently diagnosed cancer worldwide, accounting for 7.3% of all cancers. PCa mortality is the fifth most common cause of cancer death. Despite well-known factors influencing the development of PCa, such as age, race/ethnicity and family history, many researchers have raised the possibility of persistent infections with oncogenic viruses. Therefore, we aimed to assess the frequency of Epstein-Barr virus (EBV) DNA in tissue collected from PCa patients. Next, the frequency and the level of Epstein-Barr virus capsid antigen (EBVCA) and Epstein-Barr nuclear antigen 1 (EBNA1) antibodies in both IgA and IgG classes were measured. The antibody titer was also analyzed depending on the risk group, Gleason score (GS) and tumor, node, metastasis (TNM) classification. Serum samples were analyzed using the Microblot-Array EBV IgM, IgA and IgG test kits. The study group consisted of 115 patients diagnosed and histopathologically confirmed with PCa. In 49% of patients included in the study, EBV DNA was detected in the tumor tissue. The studies showed both higher seroprevalence and higher antibody titers in patients with EBV-positive PCa compared to patients with EBV-negative PCa. We also observed a dependence of antibody titer on pathological features, such as GS, risk group and T stage.

Inhibition of HDAC6 alleviates cancer‑induced bone pain by reducing the activation of NLRP3 inflammasome

Cancer‑induced bone pain (CIBP) is characterized as moderate to severe pain that negatively affects the daily functional status and quality of life of patients. When cancer cells metastasize and grow in bone marrow, this activates neuroinflammation in the spinal cord, which plays a vital role in the generation and persistence of chronic pain. In the present study, a model of CIBP was constructed by inoculating of MRMT‑1 rat breast carcinoma cells into the medullary cavity of the tibia in male Sprague‑Dawley rats. Following two weeks of surgery, CIBP rats exhibited damaged bone structure, increased pain sensitivity and impaired motor coordination. Neuroinflammation was activated in the spinal cords of CIBP rats, presenting with extensive leukocyte filtration, upregulated cytokine levels and activated astrocytes. Histone deacetylase 6 (HDAC6) works as a therapeutic target for chronic pain. The intrathecal injection of the HDAC6 inhibitor tubastatin A (TSA) in the lumbar spinal cord resulted in decreased spinal inflammatory cytokine production, suppressed spinal astrocytes activation and reduced NOD‑like receptor pyrin domain containing 3 (NLRP3) inflammasome activity. Consequently, this effect alleviated spontaneous pain and mechanical hyperalgesia and recovered motor coordination in CIBP rats. It was demonstrated by immunoprecipitation assay that TSA treatment reduced the interaction between HDAC6 and NLRP3. Cell research on C6 rat glioma cells served to verify that TSA treatment reduced HDAC6 and NLRP3 expression. In summary, the findings of present study indicated that TSA treatment alleviated cancer‑induced bone pain through the inhibition of HDAC6/NLRP3 inflammasome signaling in the spinal cord.

MicroRNAs mediated interaction of tumor microenvironment cells with breast cancer cells during bone metastasis

Breast cancer (BC) bone metastasis is primarily osteolytic and has limited therapeutic options. Metastasized BC cells prime the secondary environment in bone by forming a tumor niche, which favors their homing and colonization. The tumor microenvironment (TME) is primarily generated by the cancer cells. Bone TME is an intricate network of multiple cells, including altered bone, tumor, stromal, and immune cells. Recent findings highlight the significance of small non-coding microRNAs (miRNAs) in influencing TME during tumor metastasis. MiRNAs from TME-resident cells facilitate the interaction between the tumor and its microenvironment, thereby regulating the biological processes of tumors. These miRNAs can serve as oncogenes or tumor suppressors. Hence, both miRNA inhibitors and mimics are extensively utilized in pre-clinical trials for modulating the phenotypes of tumor cells and associated stromal cells. This review briefly summarizes the recent developments on the functional role of miRNAs secreted directly or indirectly from the TME-resident cells in facilitating tumor growth, progression, and metastasis. This information would be beneficial in developing novel targeted therapies for BC.

Downregulation of ACC expression suppresses cell viability and migration in the malignant progression of breast cancer

Exploring new diagnostic biomarkers and molecular targets is of great importance in breast cancer treatment. The present study investigated the effects of acetyl-CoA carboxylase (ACC) expression interference on the malignant progression of breast cancer cells. ACC expression was knocked down using a lentiviral vector and this was verified by quantitative polymerase chain reaction and western blotting. MCF-7 and MDA-MB-231 breast cancer cells were randomly allocated into the following groups: Normal breast cancer cells (control), breast cancer cells transduced with a negative control lentiviral vector and breast cancer cells transduced with an ACC knockdown lentiviral vector. Screening for stable transgenic strains was successful. Cell viability, apoptosis and migration were determined using Cell Counting Kit-8, flow cytometry and scratch test, respectively. The protein expression levels of N-cadherin, Vimentin and Bax were detected by western blotting. In addition, a nude mouse model of subcutaneous metastatic tumor was established using MCF-7 breast cancer cells, and tumor volume was assessed. Furthermore, pathological condition and apoptosis were detected using hematoxylin and eosin, and TUNEL staining, respectively. The protein expression levels of N-cadherin, Vimentin and Bax were detected by western blotting. The in vitro experiments showed that knockdown of ACC expression significantly decreased the viability and migration, and increased the apoptosis of MCF-7 and MDA-MB-231 breast cancer cells. In vivo experiments revealed that ACC knockdown effectively reduced the tumor volume in nude mice, and promoted tumor cell apoptosis. Both in vitro and in vivo experiments showed that ACC knockdown can reduce the protein expression levels of N-cadherin and Vimentin, and increase Bax expression. These findings suggested that downregulation of ACC expression may significantly reduce the malignant progression of breast cancer, and could be considered a potential therapeutic target.

Understanding human aging and the fundamental cell signaling link in age-related diseases: the middle-aging hypovascularity hypoxia hypothesis

Aging-related hypoxia, oxidative stress, and inflammation pathophysiology are closely associated with human age-related carcinogenesis and chronic diseases. However, the connection between hypoxia and hormonal cell signaling pathways is unclear, but such human age-related comorbid diseases do coincide with the middle-aging period of declining sex hormonal signaling. This scoping review evaluates the relevant interdisciplinary evidence to assess the systems biology of function, regulation, and homeostasis in order to discern and decipher the etiology of the connection between hypoxia and hormonal signaling in human age-related comorbid diseases. The hypothesis charts the accumulating evidence to support the development of a hypoxic milieu and oxidative stress-inflammation pathophysiology in middle-aged individuals, as well as the induction of amyloidosis, autophagy, and epithelial-to-mesenchymal transition in aging-related degeneration. Taken together, this new approach and strategy can provide the clarity of concepts and patterns to determine the causes of declining vascularity hemodynamics (blood flow) and physiological oxygenation perfusion (oxygen bioavailability) in relation to oxygen homeostasis and vascularity that cause hypoxia (hypovascularity hypoxia). The middle-aging hypovascularity hypoxia hypothesis could provide the mechanistic interface connecting the endocrine, nitric oxide, and oxygen homeostasis signaling that is closely linked to the progressive conditions of degenerative hypertrophy, atrophy, fibrosis, and neoplasm. An in-depth understanding of these intrinsic biological processes of the developing middle-aged hypoxia could provide potential new strategies for time-dependent therapies in maintaining healthspan for healthy lifestyle aging, medical cost savings, and health system sustainability.

Inhibitory Potential of Resveratrol in Cancer Metastasis: From Biology to Therapy

Cancer metastasis is a significant challenge in cancer treatment, and most existing drugs are designed to inhibit tumor growth but are often ineffective in treating metastatic cancer, which is the leading cause of cancer-related deaths. Resveratrol, a polyphenol found in grapes, berries, and peanuts, has shown potential in preclinical studies as an anticancer agent to suppress metastasis. However, despite positive results in preclinical studies, little progress has been made in clinical trials. To develop resveratrol as an effective anticancer agent, it is crucial to understand its cellular processes and signaling pathways in tumor metastasis. This review article evaluates the current state and future development strategies of resveratrol to enhance its potency against cancer metastasis within its therapeutic dose. In addition, we critically evaluate the animal models used in preclinical studies for cancer metastasis and discuss novel techniques to accelerate the translation of resveratrol from bench to bedside. The appropriate selection of animal models is vital in determining whether resveratrol can be further developed as an antimetastatic drug in cancer therapy.

RBM3 suppresses stemness remodeling of prostate cancer in bone microenvironment by modulating N6-methyladenosine on CTNNB1 mRNA

Bone metastasis is the most happened metastatic event in prostate cancer (PCa) and needs a large effort in treatment. When PCa metastasizes to the bone, the new microenvironment can induce the epigenome reprogramming and stemness remodeling of cancer cells, thereby increasing the adaptability of cancer cells to the bone microenvironment, and this even leads to the occurrence of secondary tumor metastasis. Our group has previously found that RNA binding motif 3 (RBM3) affects the stem cell-like properties of PCa by interfering with alternative splicing of CD44. However, whether RBM3, as a stress-response protein, can resist microenvironmental remodeling of PCa particularly in bone metastasis remains unknown. By co-culturing PCa cells with osteoblasts to mimic PCa bone metastases, we found that RBM3 upregulates the N6-methyladenosine (m⁶A) methylation on the mRNA of catenin beta 1 (CTNNB1) in a manner dependent on methyltransferase 3 (METTL3), an N6-adenosine-methyltransferase complex catalytic subunit. Consequently, this modification results in a decreased stability of CTNNB1 mRNA and a followed inactivation of Wnt signaling, which ultimately inhibits the stemness remodeling of PCa cells by osteoblasts. Thus, the present study may extend our understanding of the inhibitory role of RBM3 on particularly bone metastasis of PCa.

Neutrophil elastase: From mechanisms to therapeutic potential

Neutrophil elastase (NE), a major protease in the primary granules of neutrophils, is involved in microbicidal activity. NE is an important factor promoting inflammation, has bactericidal effects, and shortens the inflammatory process. NE also regulates tumor growth by promoting metastasis and tumor microenvironment remodeling. However, NE plays a role in killing tumors under certain conditions and promotes other diseases such as pulmonary ventilation dysfunction. Additionally, it plays a complex role in various physiological processes and mediates several diseases. Sivelestat, a specific NE inhibitor, has strong potential for clinical application, particularly in the treatment of coronavirus disease 2019 (COVID-19). This review discusses the pathophysiological processes associated with NE and the potential clinical applications of sivelestat.

Bibliometric analysis of worldwide research trends on breast cancer about inflammation

Background

The most prevalent cancer and the second-leading cause of cancer-related mortality in women is breast cancer. Growing interest has been shown in recent years in learning more about the processes behind the development of breast cancer. It has been shown that persistent inflammation may play a significant role in the advancement of breast cancer. However, a comprehensive and objective analysis on the state of inflammation in breast cancer research is still lacking. This study was aim to undertake a bibliometric analysis of breast cancer research associated with inflammation between 2013 and 2022 in order to identify the trends, dynamics, and scientific outputs in the field.

Methods

From 2013 to 2022, original and review publications on breast cancer and inflammation-associated research were retrieved from the Web of Science Core Collection (WOSCC) database. To examine the position of yearly publications, journals, nations, institutions, and authors, we employed two bibliometric tools (CiteSpace and VOSviewer). After that, by examining keyword visualization and keyword bursts, we determined the hot research fields related to inflammation in breast cancer.

Results

we discovered 6902 publications regarding inflammation in breast cancer by using our retrieval approach. In terms of the number of publications, The United States ranked first in the global study, followed by China and Italy. In terms of institutions, the University of Texas System, UT MD Anderson Cancer Center, and University of California System are in the top 3 for the quantity of publications published. The most popular journal for this field research is "CANCERS." Ueno NT, Woodward WA, Cristofanilli M, and others have made significant contributions to the understanding of inflammation in breast cancer. In the end, we conducted a biclustering analysis on keywords and discovered three clusters that represent research hotspots.

Conclusion

According to the global trend, the research output of inflammation in breast cancer is increasing. The information provided in this article, including the cooperation network information of authors, nations, journals, and institutions, may help researchers to better understand hotspots and developing patterns in this discipline. At present, the focus of study gradually shifts from "phenotype study" to "therapeutic research". It is recommended to pay attention to the latest hot spots, such as targeted therapy, antimicrobial activity and nanoparticle.

AIM2 upregulation promotes metastatic progression and PD-L1 expression in lung adenocarcinoma

Cancer metastasis leading to the dysfunction of invaded organs is the main cause of the reduced survival rates in lung cancer patients. However, the molecular mechanism for lung cancer metastasis remains unclear. Recently, the increased activity of inflammasome appeared to correlate with the metastatic progression and immunosuppressive ability of various cancer types. Our results showed that the mRNA levels of absence in melanoma 2 (AIM2), one of the inflammasome members, are extensively upregulated in primary tumors compared with normal tissues derived from the TCGA lung adenocarcinoma (LUAD) database. Moreover, Kaplan-Meier analysis demonstrated that a higher mRNA level of AIM2 refers to a poor prognosis in LUAD patients. Particularly, AIM2 upregulation is closely correlated with smoking history and the absence of EGFR/KRAS/ALK mutations in LUAD. We further showed that the endogenous mRNA levels of AIM2 are causally associated with the metastatic potentials of the tested LUAD cell lines. AIM2 knockdown suppressed but overexpression promoted the migration ability and lung colony-forming ability of tested LUAD cells. In addition, we found that AIM2 upregulation is closely associated with an increased level of immune checkpoint gene set, as well as programmed cell death-ligand 1 (PD-L1) transcript, in TCGA LUAD samples. AIM2 knockdown predominantly repressed but overexpression enhanced PD-L1 expression via altering the activity of PD-L1 transcriptional regulators NF-κB/STAT1 in LUAD cells. Our results not only provide a possible mechanism underlying the AIM2-promoted metastatic progression and immune evasion of LUAD but also offer a new strategy for combating metastatic/immunosuppressive LUAD via targeting AIM2 activity.

Role of Interleukin-1 family in bone metastasis of prostate cancer

Prostate cancer (PCa) is one of the most fatal diseases in male patients with high bone metastatic potential. Bone metastasis severely shortens overall survival and brings skeletal-related events (SREs) which reduces the life quality of patients, and this situation is currently regarded as irreversible and incurable. The progression and metastasis of PCa are found to be closely associated with inflammatory cytokines and chemokines. As pivotal members of inflammatory cytokines, Interleukin-1 (IL-1) family plays a crucial role in this process. Elevated expression of IL-1 family was detected in PCa patients with bone metastasis, and accumulating evidences proved that IL-1 family could exert vital effects on the progression and bone metastasis of many cancers, while some members have dual effects. In this review, we discuss the role of IL-1 family in the bone metastasis of PCa. Furthermore, we demonstrate that many members of IL-1 family could act as pivotal biomarkers to predict the clinical stage and prognosis of PCa patients. More importantly, we have elucidated the role of IL-1 family in the bone metastasis of PCa, which could provide potential targets for the treatment of PCa bone metastasis and probable directions for future research.

Multiple pathogens and prostate cancer

BACKGROUND

The aim of this review is to consider whether multiple pathogens have roles in prostate cancer.

METHODS

We have reviewed case control studies in which infectious pathogens in prostate cancer were compared to normal and benign prostate tissues. We also reviewed additional evidence from relevant published articles.

RESULTS

We confirmed that high risk human papilloma viruses are a probable cause of prostate cancer. We judged Escherichia coli, Cutibacterium acnes, Neisseria gonorrhoea, Herpes simplex, Epstein Barr virus and Mycoplasmas as each having possible but unproven roles in chronic prostatic inflammation and prostate cancer. We judged Cytomegalovirus, Chlamydia trachomatis, Trichomonas vaginalis and the Polyoma viruses as possible but unlikely to have a role in prostate cancer.

CONCLUSIONS AND ACTIONS

The most influential cause of prostate cancer appears to be infection induced chronic inflammation. Given the high prevalence of prostate cancer it is important for action to can be taken without waiting for additional conclusive evidence. These include: 1. Encouragement of all boys (as well as girls) to have HPV vaccines 2. The vigorous use of antibiotics to treat all bacterial pathogens identified in the urogenital tract 3. The use of antiviral medications to control herpes infections 4. Education about safe sexual practices.

Metagenomics studies for the diagnosis and treatment of prostate cancer

AIM

Mutation occurs in the prostate cell genes, leading to abnormal prostate proliferation and ultimately cancer. Prostate cancer (PC) is one of the most common cancers amongst men, and its prevalence worldwide increases relative to men's age. About 16% of the world's cancers are the result of microbes in the human body. Impaired population balance of symbiosis microbes in the human reproductive system is linked to PC development.

DISCUSSION

With the advent of metagenomics science, the genome sequence of the microbiota of the human body has been unveiled. Therefore, it is now possible to identify a higher range of microbiome changes in PC tissue via the Next Generation Technique, which will have positive consequences in personalized medicine. In this review, we intend to question the role of metagenomics studies in the diagnosis and treatment of PC.

CONCLUSION

The microbial imbalance in the men's genital tract might have an effect on prostate health. Based on next-generation sequencing-generated data, Proteobacteria, Firmicutes, Actinobacteria, and Bacteriodetes are the nine frequent phyla detected in a PC sample, which might be involved in inducing mutation in the prostate cells that cause cancer.

Mechanobiology of Bone Metastatic Cancer

PURPOSE OF REVIEW

In this review, we provide an overview of what is currently known about the impacts of mechanical stimuli on metastatic tumor-induced bone disease (TIBD). Further, we focus on the role of the osteocyte, the skeleton's primary mechanosensory cell, which is central to the skeleton's mechanoresponse, sensing and integrating local mechanical stimuli, and then controlling the downstream remodeling balance as appropriate.

RECENT FINDINGS

Exercise and controlled mechanical loading have anabolic effects on bone tissue in models of bone metastasis. They also have anti-tumorigenic properties, in part due to offsetting the vicious cycle of osteolytic bone loss as well as regulating inflammatory signals. The impacts of metastatic cancer on the mechanosensory function of osteocytes remains unclear. Increased mechanical stimuli are a potential method for mitigating TIBD.

Dual anticancer role of metformin: an old drug regulating AMPK dependent/independent pathways in metabolic, oncogenic/tumorsuppresing and immunity context

Metformin has been known to treat type 2 diabetes for decades and is widely prescribed antidiabetic drug. Recently, its anticancer potential has also been discovered. Moreover, metformin has low cost thus it has attained profound research interest. Comprehensing the complexity of the molecular regulatory networks in cancer provides a mode for advancement of research in cancer development and treatment. Metformin targets many pathways that play an important role in cancer cell survival outcome. Here, we described anticancer activity of metformin on the AMPK dependent/independent mechanisms regulating metabolism, oncogene/tumor suppressor signaling pathways together with the issue of clinical studies. We also provided brief overwiev about recently described metformin's role in cancer immunity. Insight in these complex molecular networks, will simplify application of metformin in clinical trials and contribute to improvement of anti-cancer therapy.

The Breast Tumor Microenvironment: A Key Player in Metastatic Spread

The tumor microenvironment plays a pivotal role in the tumorigenesis, progression, and metastatic spread of many cancers including breast. There is now increasing evidence to support the observations that a bidirectional interplay between breast cancer cells and stromal cells exists within the tumor and the tumor microenvironment both at the primary tumor site and at the metastatic site. This interaction occurs through direct cell to cell contact, or by the release of autocrine or paracrine factors which can activate pro-tumor signaling pathways and modulate tumor behavior. In this review, we will highlight recent advances in our current knowledge about the multiple interactions between breast cancer cells and neighboring cells (fibroblasts, endothelial cells, adipocytes, innate and adaptive immune cells) in the tumor microenvironment that coordinate to regulate metastasis. We also highlight the role of exosomes and circulating tumor cells in facilitating breast cancer metastasis. We discuss some key markers associated with stromal cells in the breast tumor environment and their potential to predict patient survival and guide treatment. Finally, we will provide some brief perspectives on how current technologies may lead to the development of more effective therapies for the clinical management of breast cancer patients.

Intracellular Signaling Responses Induced by Radiation within an In Vitro Bone Metastasis Model after Pre-Treatment with an Estrone Analogue

2-Ethyl-3-O-sulfamoyl-estra-1,3,5(10)16-tetraene (ESE-16) is an in silico-designed estradiol analogue which has improved the parent compound’s efficacy in anti-cancer studies. In this proof-of-concept study, the potential radiosensitizing effects of ESE-16 were investigated in an in vitro deconstructed bone metastasis model. Prostate (DU 145) and breast (MDA-MB-231) tumor cells, osteoblastic (MC3T3-E1) and osteoclastic (RAW 264.7) bone cells and human umbilical vein endothelial cells (HUVECs) were representative components of such a lesion. Cells were exposed to a low-dose ESE-16 for 24 hours prior to radiation at non-lethal doses to determine early signaling and molecular responses of this combination treatment. Tartrate-resistant acid phosphatase activity and actin ring formation were investigated in osteoclasts, while cell cycle progression, reactive oxygen species generation and angiogenic protein expression were investigated in HUVECs. Increased cytotoxicity was evident in tumor and endothelial cells while bone cells appeared to be spared. Increased mitotic indices were calculated, and evidence of increased deoxyribonucleic acid damage with retarded repair, together with reduced metastatic signaling was observed in tumor cells. RAW 264.7 macrophages retained their ability to differentiate into osteoclasts. Anti-angiogenic effects were observed in HUVECs, and expression of hypoxia-inducible factor 1-α was decreased. Through preferentially inducing tumor cell death and potentially inhibiting neovascularization whilst preserving bone physiology, this low-dose combination regimen warrants further investigation for its promising therapeutic application in bone metastases management, with the additional potential of limited treatment side effects.