Phenotypic switch in blood: effects of pro-inflammatory cytokines on breast cancer cell aggregation and adhesion

Association Between Neighborhood Opportunity, Allostatic Load, and All-Cause Mortality in Patients With Breast Cancer

PURPOSE

Adverse neighborhood contextual factors may affect breast cancer outcomes through environmental, psychosocial, and biological pathways. The objective of this study is to examine the relationship between allostatic load (AL), neighborhood opportunity, and all-cause mortality among patients with breast cancer.

METHODS

Women age 18 years and older with newly diagnosed stage I-III breast cancer who received surgical treatment between January 1, 2012, and December 31, 2020, at a National Cancer Institute Comprehensive Cancer Center were identified. Neighborhood opportunity was operationalized using the 2014-2018 Ohio Opportunity Index (OOI), a composite measure derived from neighborhood level transportation, education, employment, health, housing, crime, and environment. Logistic and Cox regression models tested associations between the OOI, AL, and all-cause mortality.

RESULTS

The study cohort included 4,089 patients. Residence in neighborhoods with low OOI was associated with high AL (adjusted odds ratio, 1.21 [95% CI, 1.05 to 1.40]). On adjusted analysis, low OOI was associated with greater risk of all-cause mortality (adjusted hazard ratio [aHR], 1.45 [95% CI, 1.11 to 1.89]). Relative to the highest (99th percentile) level of opportunity, risk of all-cause mortality steeply increased up to the 70th percentile, at which point the rate of increase plateaued. There was no interaction between the composite OOI and AL on all-cause mortality (P = .12). However, there was a higher mortality risk among patients with high AL residing in lower-opportunity environments (aHR, 1.96), but not in higher-opportunity environments (aHR, 1.02; P interaction = .02).

CONCLUSION

Lower neighborhood opportunity was associated with higher AL and greater risk of all-cause mortality among patients with breast cancer. Additionally, environmental factors and AL interacted to influence all-cause mortality. Future studies should focus on interventions at the neighborhood and individual level to address socioeconomically based disparities in breast cancer.

Circulating tumor cells clusters and their role in Breast cancer metastasis; a review of literature

Breast cancer is a significant and deadly threat to women globally. Moreover, Breast cancer metastasis is a complicated process involving multiple biological stages, which is considered a substantial cause of death, where cancer cells spread from the original tumor to other organs in the body-representing the primary mortality factor. Circulating tumor cells (CTCs) are cancer cells detached from the primary or metastatic tumor and enter the bloodstream, allowing them to establish new metastatic sites. CTCs can travel alone or in groups called CTC clusters. Studies have shown that CTC clusters have more potential for metastasis and a poorer prognosis than individual CTCs in breast cancer patients. However, our understanding of CTC clusters' formation, structure, function, and detection is still limited. This review summarizes the current knowledge of CTC clusters' biological properties, isolation, and prognostic significance in breast cancer. It also highlights the challenges and future directions for research and clinical application of CTC clusters.

Anticarcinogenic Effects of Gold Nanoparticles and Metformin Against MCF-7 and A549 Cells

Metformin is commonly prescribed to people with diabetes. Metformin has been shown in previous studies to be able to prevent the growth of cancer cells. This study aims to investigate the effects of metformin and gold nanoparticles in MCF7 breast cancer and A549 lung cell lines. The effects of metformin and gold nanoparticles on MCF7 breast cancer and A549 lung cells were determined on cells grown in 24 h cell culture. MCF-7 and A549 cells were incubated for 24 h with the treatment of escalating molar concentrations of ifosfamide. The MTT assay was used to determine the cytotoxicity of metformin toward MCF7 and A549 cell lines. The expression of Bax, BCL2, PI3K, Akt3, mTOR, Hsp60, Hsp70, and TNF-α was measured by RT-PCR. Metformin and gold nanoparticles inhibited the proliferation of MCF-7 and A549 cells in a dose and time-dependent manner with an IC50 value of 5 µM and 10 µg/mL. RT-PCR assays showed ifosfamide + metformin + gold nanoparticles significantly reduced the expression of BCL2, PI3K, Akt3, mTOR, Hsp60 and Hsp70 and increased the expression of TNF-α and Bax. The findings obtained in this study suggest that further studies should be conducted, and metformin and gold nanoparticles can be used in breast cancer and lung cancer treatments.

How circulating tumor cluster biology contributes to the metastatic cascade: from invasion to dissemination and dormancy

Circulating tumor cells (CTCs) are known to be prognostic for metastatic relapse and are detected in patients as solitary cells or cell clusters. Circulating tumor cell clusters (CTC clusters) have been observed clinically for decades and are of significantly higher metastatic potential compared to solitary CTCs. Recent studies suggest distinct differences in CTC cluster biology regarding invasion and survival in circulation. However, differences regarding dissemination, dormancy, and reawakening require more investigations compared to solitary CTCs. Here, we review the current state of CTC cluster research and consider their clinical significance. In addition, we discuss the concept of collective invasion by CTC clusters and molecular evidence as to how cluster survival in circulation compares to that of solitary CTCs. Molecular differences between solitary and clustered CTCs during dormancy and reawakening programs will also be discussed. We also highlight future directions to advance our current understanding of CTC cluster biology.

Exploring the 1,3-benzoxazine chemotype for cannabinoid receptor 2 as a promising anti-cancer therapeutic

The discovery of selective agonists of cannabinoid receptor 2 (CB2) is strongly pursued to successfully tuning endocannabinoid signaling for therapeutic purposes. However, the design of selective CB2 agonists is still challenging because of the high homology with the cannabinoid receptor 1 (CB1) and for the yet unclear molecular basis of the agonist/antagonist switch. Here, the 1,3-benzoxazine scaffold is presented as a versatile chemotype for the design of CB2 agonists from which 25 derivatives were synthesized. Among these, compound 7b5 (CB2 EC50 = 110 nM, CB1 EC50 > 10 μM) demonstrated to impair proliferation of triple negative breast cancer BT549 cells and to attenuate the release of pro-inflammatory cytokines in a CB2-dependent manner. Furthermore, 7b5 abrogated the activation of extracellular signal-regulated kinase (ERK) 1/2, a key pro-inflammatory and oncogenic enzyme. Finally, molecular dynamics studies suggested a new rationale for the in vitro measured selectivity and for the observed agonist behavior.

Predictive Role of Soluble IL-6R, TNF-R1/2, and Cell Adhesion Molecules Serum Levels in the Preoperative and Adjuvant Therapy in Women with Nonmetastatic Breast Cancer: A Preliminary Study

Soluble cell adhesion molecules (sCAMs) are involved in the development of neoplastic diseases. sCAMs can block lymphocytes and promote angiogenesis and migration of breast cancer (BC) cells. Interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) enhance metastatic potential via upregulation of CAMs. We assessed soluble interleukin-6 receptor subunit alpha (IL-6Ra), TNF-R1, TNF-R2, E-selectin, P-selectin, VCAM-1, ICAM-1, and EpCAM in 89 women with stage I-III BC and 28 healthy women. Blood samples were obtained at the beginning of neoadjuvant/induction (N = 49) or adjuvant treatment (N = 40), and after 2 months. Surgery revealed complete response in 29.4% of patients, partial response in 67%, and stable disease in 5.9%. Achieving a pathological response was 4 times greater for baseline levels of sIL-6Ra >5.63 ng/mL [odds ratio (OR) = 4.1, 95% confidence interval (CI): 0.8-20.4, P = 0.08] and more than 6 times for soluble tumor necrosis factor receptor 1 (sTNF-R1) ≥ 0.97 ng/mL (OR = 6.2, 95% CI: 1.2-32.3, P < 0.05). Compared with the control group, serum sP-selectin, soluble epithelial cell adhesion molecule (sEpCAM), and sTNF-R2 concentrations were significantly higher in patients who started adjuvant therapy (P < 0.05) and preoperative therapy (P < 0.01). Baseline serum sIL-6Ra concentrations were significantly higher in patients before surgery than in patients after tumor resection (P < 0.05), independent of the follow-up time. The baseline serum soluble receptors of IL-6 (sIL-6R) and TNF-α (sTNF-R1) concentrations have a predictive value for preoperative therapy in patients with BC.

Association of human papillomavirus with breast cancer: a new perspective on an old debate

Breast cancer is a common cancer in the female population. Despite remarkable progress in the treatment of this cancer, its exact etiology is still unknown. Since the first evidence of an association between breast cancer and human papillomavirus (HPV) was provided in 1992, numerous studies have explored this subject but have reached contradictory results. In this review, the authors examine the existing evidence and hypotheses regarding the pathways whereby HPV infection can reach breast cells and the mediators linking HPV oncoproteins to breast cancer pathogenesis. Furthermore, the authors discuss contradictory findings regarding the association of HPV with breast cancer. Showing the link between HPV infection and increased genomic instability, reduced apoptosis, immune system dysfunction and progression of metastasis, the reviewed findings highlight the importance of active presence or history of HPV infection as a prognostic factor for breast tumor development.

Metabolic Reprogramming and Lipophagy Mediates Survival of Ascites Derived Metastatic Ovarian Cancer Cells

OBJECTIVE

The study was aimed at understanding the survival of metastatic ovarian cancer spheroids in the malignant ascites microenvironment.

METHODS

All the assays were performed using aseptically collected patient samples. The cells were characterized for the expression of ovarian and cancer stem cell markers using immunocytochemistry. The presence of lipid in the primary metastatic cancer spheroids were confirmed by neutral fat staining using Oil Red-O and transmission electron microscopy. The mRNA expression of autophagy and lipid metabolism genes was analyzed using RT-PCR. The lipid content was analyzed using lipidomics analysis. Etomoxir and chloroquine were used to study the effect of inhibition of autophagy in the metastatic cells. The data were analyzed using appropriate statistical tools and a p-value <0.05 was considered to be statistically significant.

RESULTS

Metastatic ovarian cancer spheroids exhibit cancer stem like properties and undergo a metabolic reprogramming when they disseminate from the primary tumor. We report here the accumulation of numerous cytoplasmic lipid droplets and lipophagic vesicles in the metastatic cells in contrast to their primary tumors. In addition we also report that these cells depend on lipophagy for the utilization of lipids rather than the conventional lipolytic pathway. The lipidomics analysis data reveals that the metastatic cells possess high levels of unsaturated fatty acids. We have also reported the occurrence of distinct accumulation of multiple nuclei in the patient derived metastatic cells. Inhibition of beta-oxidation and autophagic machinery using etomoxir and chloroquine resulted in cell death suggesting a potential mode to suppress metastatic cancer cells.

CONCLUSION

Metabolic reprogramming is a characteristic feature of the metastatic ovarian cancer cells that are persisting in the malignant ascites. Targeting of the metastatic by gaining an insight into the various metabolic and molecular changes that occur in the metastatic niche provides a promising therapeutic approach in management of the disease.

HepT1-derived murine models of high-risk hepatoblastoma display vascular invasion, metastasis, and circulating tumor cells

Hepatoblastoma (HB) is the most common pediatric primary liver malignancy, and survival for high-risk disease approaches 50%. Mouse models of HB fail to recapitulate hallmarks of high-risk disease. The aim of this work was to generate murine models that show high-risk features including multifocal tumors, vascular invasion, metastasis, and circulating tumor cells (CTCs). HepT1 cells were injected into the livers or tail veins of mice, and tumor growth was monitored with magnetic resonance and bioluminescent imaging. Blood was analyzed with fluorescence-activated cell sorting to identify CTCs. Intra- and extra-hepatic tumor samples were harvested for immunohistochemistry and RNA and DNA sequencing. Cell lines were grown from tumor samples and profiled with RNA sequencing. With intrahepatic injection of HepT1 cells, 100% of animals grew liver tumors and showed vascular invasion, metastasis, and CTCs. Mutation profiling revealed genetic alterations in seven cancer-related genes, while transcriptomic analyses showed changes in gene expression with cells that invade vessels. Tail vein injection of HepT1 cells resulted in multifocal, metastatic disease. These unique models will facilitate further meaningful studies of high-risk HB.

This article has an associated First Person interview with the first author of the paper.

Summary: In this work, we developed and thoroughly characterized several unique models of hepatoblastoma derived from the HepT1 cell line that show high-risk features.

Sweet Bee Venom Triggers Multiple Cell Death Pathways or Spurs Acute Cell Rupture According to Its Concentration in THP-1 Monocytic Leukemia Cells

Sweet bee venom (sBV) contains various pharmacologically active components of bee venom (BV), but it is modified via the removal of the harmful substances found in BV. Thus, sBV has been used for pain relief in Oriental medicine but has only recently been applied for the treatment of various diseases. In this study, we examined the pharmacological effects and immunomodulatory functions of sBV in THP-1 monocytic leukemia cells. Growth inhibition and cell death were observed according to the concentration of sBV. However, the rapid collapse of cell cycle distribution was shown at 20 μg/mL sBV treatment, indicating that sBV led to cell death or acute cell rupture according to concentration. sBV administration activated Caspase-9, PARP1, RIPK1, and RIPK3, suggesting that the pharmacological actions of sBV were associated with induction of apoptosis and necroptosis. On the other hand, sBV or LPS administration increased cytokine expression, including IL-1β, and showed synergistic cell death in combinatory treatment conditions. Moreover, combinatory administration of sBV and LPS induced severe damage or death during egg development. This result implies that sBV exhibits both pharmacological and toxic effects depending on its concentration. Therefore, sBV might be a promising therapeutic approach, but optimal concentration should be considered before treatment.

Tumor cell E-selectin ligands determine partialefficacy of bortezomib on spontaneous lung metastasis formation of solid human tumors in vivo

Extravasation of circulating tumor cells (CTCs) is critical for metastasis and is initiated by adhesive interactions between glycoligands on CTCs and E-selectin on endothelia. Here, we show that the clinically approved proteasome inhibitor bortezomib (BZM; Velcade) counteracts the cytokine-dependent induction of E-selectin in the lung mediated by the primary tumor, thereby impairing endothelial adhesion and thus spontaneous lung metastasis in vivo. However, the efficacy of BZM crucially depends on the tumor cells' E-selectin ligands, which determine distinct adhesion patterns. The canonical ligands sialyl-Lewis A (sLeA) and sLeX mediate particularly high-affinity E-selectin binding so that the incomplete E-selectin-reducing effect of BZM is not sufficient to disrupt adhesion or metastasis. In contrast, tumor cells lacking sLeA/X nevertheless bind E-selectin, but with low affinity, so that adhesion and lung metastasis are significantly diminished. Such low-affinity E-selectin ligands apparently consist of sialylated MGAT5 products on CD44. BZM no longer has anti-metastatic activity after CD44 knockdown in sLeA/X-negative tumor cells or E-selectin knockout in mice. sLeA/X can be determined by immunohistochemistry in cancer samples, which might aid patient stratification. These data suggest that BZM might act as a drug for inhibiting extravasation and thus distant metastasis formation in malignancies expressing low-affinity E-selectin ligands.

Biomimetic Microfluidic Platforms for the Assessment of Breast Cancer Metastasis

Of around half a million women dying of breast cancer each year, more than 90% die due to metastasis. Models necessary to understand the metastatic process, particularly breast cancer cell extravasation and colonization, are currently limited and urgently needed to develop therapeutic interventions necessary to prevent breast cancer metastasis. Microfluidic approaches aim to reconstitute functional units of organs that cannot be modeled easily in traditional cell culture or animal studies by reproducing vascular networks and parenchyma on a chip in a three-dimensional, physiologically relevant in vitro system. In recent years, microfluidics models utilizing innovative biomaterials and micro-engineering technologies have shown great potential in our effort of mechanistic understanding of the breast cancer metastasis cascade by providing 3D constructs that can mimic in vivo cellular microenvironment and the ability to visualize and monitor cellular interactions in real-time. In this review, we will provide readers with a detailed discussion on the application of the most up-to-date, state-of-the-art microfluidics-based breast cancer models, with a special focus on their application in the engineering approaches to recapitulate the metastasis process, including invasion, intravasation, extravasation, breast cancer metastasis organotropism, and metastasis niche formation.

Overcoming TRAIL-resistance by sensitizing prostate cancer 3D spheroids with taxanes

Three-dimensional spheroid cultures have been shown to better physiologically mimic the cell-cell and cell-matrix interactions that occur in solid tumors more than traditional 2D cell cultures. One challenge in spheroid production is forming and maintaining spheroids of uniform size. Here, we developed uniform, high-throughput, multicellular spheroids that self-assemble using microwell plates. DU145 and PC3 cells were cultured as 2D monolayers and 3D spheroids to compare sensitization of TRAIL-resistance cancer cells to TRAIL mediated apoptosis via chemotherapy based on dimensionality. Monocultured monolayers and spheroids were treated with soluble TRAIL alone (24 hr), DTX or CBZ alone (24 hr), or a combination of taxane and TRAIL (24 + 24 hr) to determine the effectiveness of taxanes as TRAIL sensitizers. Upon treatment with soluble TRAIL or taxanes solely, monolayer cells and spheroids exhibited no significant reduction in cell viability compared to the control, indicating that both cell lines are resistant to TRAIL and taxane alone in 2D and 3D. Pretreatment with CBZ or DTX followed by TRAIL synergistically amplified apoptosis in 2D and 3D DU145 cell cultures. PC3 spheroids were more resistant to the combination therapy, displaying a more additive effect in the DTX + TRAIL group compared to 2D. There was a downregulation of DR4/5 expression in spheroid form compared to monolayers in each cell line. Additionally, normal fibroblasts (NFs) and cancer-associated fibroblasts (CAFs) were cocultured with both PCa cell lines as spheroids to determine if CAFs confer additional resistance to chemotherapy. We determined that co-cultured spheroids show similar drug resistance to monocultured spheroids when treated with taxane plus TRAIL treatment. Collectively, these findings suggest how the third dimension and cocultures of different cell types effect the sensitization of androgen-independent prostate cancer cells to TRAIL, suggesting therapeutic targets that could overcome TRAIL-resistance in metastatic castration-resistant prostate cancer (mCRPC).

CHD1 loss negatively influences metastasis-free survival in R0-resected prostate cancer patients and promotes spontaneous metastasis in vivo

The outcome of prostate cancer (PCa) patients is highly variable and depends on whether or not distant metastases occur. Multiple chromosomal deletions have been linked to early tumor marker PSA recurrence (biochemical relapse, BCR) after radical prostatectomy (RP), but their potential role for distant metastasis formation is largely unknown. Here, we specifically analyzed whether deletion of the tumor suppressor CHD1 (5q21) influences the post-surgical risk of distant metastasis and whether CHD1 loss directly contributes to metastasis formation in vivo. By considering >6800 patients we found that the CHD1 deletion negatively influences metastasis-free survival in R0 patients (HR: 2.32; 95% CI: 1.61, 3.33; p < 0.001) independent of preoperative PSA, pT stage, pN status, Gleason Score, and BCR. Moreover, CHD1 deletion predicts shortened BCR-free survival in pT2 patients and cancer-specific survival in all patients. In vivo, CHD1 loss increases spontaneous pulmonary metastasis formation in two distinct PCa models coupled with a higher number of multicellular colonies as compared to single-cell metastases. Transcriptome analyses revealed down-regulation of the PCa-specific metastasis suppressor and TGFβ signaling regulator PMEPA1 after CHD1 depletion in both tested PCa models. CHD1 loss increases the risk of postoperative metastasis in R0-resected PCa patients and promotes spontaneous metastasis formation in vivo.

Metabolic Syndrome: does this influence breast cancer outcomes in the triple-negative population?

INTRODUCTION

Metabolic syndrome (MS) is defined by having at least 3 of 4 components: obesity, dyslipidemia, hypertension (HTN), and diabetes. Prior studies analyzed the individual components of MS for all breast cancers which are predominantly hormone positive. Our study is the first to evaluate MS in triple-negative breast cancer (TNBC).

METHODS

A retrospective review of TNBC from 2007 to 2013 identified 177 patients with complete information for statistical analysis. Cox proportional hazards models were used to test the association between MS, disease-free survival (DFS), and overall survival (OS).

RESULTS

48 (27%) patients had MS. After controlling for age, race, pathologic stage, surgery type, and additional comorbidities outside of MS, MS was significantly associated with poorer DFS (adjusted HR: 2.24, p = 0.030), but not associated with OS (adjusted HR: 1.92, p = 0.103). HTN was significantly associated with poorer DFS (adjusted HR: 3.63, p = 0.006) and OS (adjusted HR: 3.45, p = 0.035) in the univariable and multivariable analyses. Diabetes was not associated with worse OS or DFS. The 5-year age-adjusted OS rates for 60-year-old patients with and without diabetes were 85.8% and 87.3%, respectively. The age-adjusted 5-year OS rate for 60-year old patients was higher in patients with a body mass index (BMI) > 30 (90.2%) versus BMIs of 25-29.9 (88.2%) or < 25 (83.5%).

CONCLUSION

In the TNBC population, MS was significantly associated with poorer DFS, but not associated with OS. HTN was the only component of MS that was significantly associated with both DFS and OS. Obesity has a potential small protective benefit in the TNBC population.

Inhibitory effect of flavonoid xanthomicrol on triple-negative breast tumor via regulation of cancer-associated microRNAs

Breast cancer is the leading cause of cancer death in women worldwide. Due to the side effects of current chemo-reagents on healthy tissues, it is essential to search for alternative compounds with less toxicity and better efficacy. In the present study, we have investigated the anticancer effects of flavonoid xanthomicrol on the mice breast cancer model using MTT assay, cell cycle and Annexin/PI analysis, colony formation assay, H&E staining, immunohistochemistry, and miRNA analysis. Our results demonstrated that xanthomicrol decreased the cell viability and clonogenic capability, induced G1-arrest and apoptosis in the breast cancer cells in vitro, and caused a significant reduction in the volume and weight of mice tumors in vivo. In addition, xanthomicrol reduced the expression of TNFα, VEGF, MMP9, and Ki67, while upregulating the expression of apoptotic markers such as Bax, caspase3, and caspase9. Finally, the expression of miR21, miR27, and miR125, known as oncomirs, decreased significantly after xanthomicrol administration, while the expression of miR29 and miR34, functioning as tumor suppressors, increased significantly (p < .001). Our data demonstrated that xanthomicrol can induce apoptosis and suppress angiogenesis in breast cancer cells due to its inhibitory effect on oncomirs and its stimulatory effect on tumor suppressor miRNAs.

The Importance of Breast Adipose Tissue in Breast Cancer

Adipose tissue is a complex endocrine organ, with a role in obesity and cancer. Adipose tissue is generally linked to excessive body fat, and it is well known that the female breast is rich in adipose tissue. Hence, one can wonder: what is the role of adipose tissue in the breast and why is it required? Adipose tissue as an organ consists of adipocytes, an extracellular matrix (ECM) and immune cells, with a significant role in the dynamics of breast changes throughout the life span of a female breast from puberty, pregnancy, lactation and involution. In this review, we will discuss the importance of breast adipose tissue in breast development and its involvement in breast changes happening during pregnancy, lactation and involution. We will focus on understanding the biology of breast adipose tissue, with an overview on its involvement in the various steps of breast cancer development and progression. The interaction between the breast adipose tissue surrounding cancer cells and vice-versa modifies the tumor microenvironment in favor of cancer. Understanding this mutual interaction and the role of breast adipose tissue in the tumor microenvironment could potentially raise the possibility of overcoming breast adipose tissue mediated resistance to therapies and finding novel candidates to target breast cancer.

Xenograft-derived mRNA/miR and protein interaction networks of systemic dissemination in human prostate cancer

BACKGROUND

Distant metastasis formation is the major clinical problem in prostate cancer (PCa) and the underlying mechanisms remain poorly understood. Our aim was to identify novel molecules that functionally contribute to human PCa systemic dissemination based on unbiased approaches.

METHODS

We compared mRNA, microRNA (miR) and protein expression levels in established human PCa xenograft tumours with high (PC-3), moderate (VCaP) or weak (DU-145) spontaneous micrometastatic potential. By focussing on those mRNAs, miRs and proteins that were differentially regulated among the xenograft groups and known to interact with each other we constructed dissemination-related mRNA/miR and protein/miR networks. Next, we clinically and functionally validated our findings.

RESULTS

Besides known determinants of PCa progression and/or metastasis, our interaction networks include several novel candidates. We observed a clear role of epithelial-to-mesenchymal transition (EMT) pathways for PCa dissemination, which was additionally confirmed by an independent human PCa model (ARCAP-E/-M). Two converging nodes, CD46 (decreasing with metastatic potential) and DDX21 (increasing with metastatic potential), were used to test the clinical relevance of the networks. Intriguingly, both network nodes consistently added prognostic information for patients with PCa whereas CD46 loss predicted poor outcome independent of established parameters. Accordingly, depletion of CD46 in weakly metastatic PCa cells induced EMT-like properties in vitro and spontaneous micrometastasis formation in vivo.

CONCLUSIONS

The clinical and functional relevance of the dissemination-related interaction networks shown here could be successfully validated by proof-of-principle experiments. Therefore, we suggest a direct pro-metastatic, clinically relevant role for the multiple novel candidates included in this study; these should be further exploited by future studies.

Tumor Necrosis Factor α Blockade: An Opportunity to Tackle Breast Cancer

Breast cancer is the most frequently diagnosed cancer and the principal cause of mortality by malignancy in women and represents a main problem for public health worldwide. Tumor necrosis factor α (TNFα) is a pro-inflammatory cytokine whose expression is increased in a variety of cancers. In particular, in breast cancer it correlates with augmented tumor cell proliferation, higher malignancy grade, increased occurrence of metastasis and general poor prognosis for the patient. These characteristics highlight TNFα as an attractive therapeutic target, and consequently, the study of soluble and transmembrane TNFα effects and its receptors in breast cancer is an area of active research. In this review we summarize the recent findings on TNFα participation in luminal, HER2-positive and triple negative breast cancer progression and metastasis. Also, we describe TNFα role in immune response against tumors and in chemotherapy, hormone therapy, HER2-targeted therapy and anti-immune checkpoint therapy resistance in breast cancer. Furthermore, we discuss the use of TNFα blocking strategies as potential therapies and their clinical relevance for breast cancer. These TNFα blocking agents have long been used in the clinical setting to treat inflammatory and autoimmune diseases. TNFα blockade can be achieved by monoclonal antibodies (such as infliximab, adalimumab, etc.), fusion proteins (etanercept) and dominant negative proteins (INB03). Here we address the different effects of each compound and also analyze the use of potential biomarkers in the selection of patients who would benefit from a combination of TNFα blocking agents with HER2-targeted treatments to prevent or overcome therapy resistance in breast cancer.

Modeling Spontaneous Bone Metastasis Formation of Solid Human Tumor Xenografts in Mice

The majority of cancer-related deaths are due to hematogenous metastases, and the bone marrow (BM) represents one of the most frequent metastatic sites. To study BM metastasis formation in vivo, the most efficient approach is based on intracardiac injection of human tumor cells into immunodeficient mice. However, such a procedure circumvents the early steps of the metastatic cascade. Here we describe the development of xenograft mouse models (balb/c rag2^-/- and severe combined immunodeficient (SCID)), in which BM metastases are spontaneously derived from subcutaneous (s.c.) primary tumors (PTs). As verified by histology, the described methodology including ex vivo bioluminescence imaging (BLI) even enabled the detection of micrometastases in the BM. Furthermore, we established sublines from xenograft primary tumors (PTs) and corresponding BM (BM) metastases using LAN-1 neuroblastoma xenografts as a first example. In vitro "metastasis" assays (viability, proliferation, transmigration, invasion, colony formation) partially indicated pro-metastatic features of the LAN-1-BM compared to the LAN-1-PT subline. Unexpectedly, after s.c. re-injection into mice, LAN-1-BM xenografts developed spontaneous BM metastases less frequently than LAN-1-PT xenografts. This study provides a novel methodologic approach for modelling the spontaneous metastatic cascade of human BM metastasis formation in mice. Moreover, our data indicate that putative bone-metastatic features get rapidly lost upon routine cell culture.

Disadvantaged neighborhoods and racial disparity in breast cancer outcomes: the biological link

Neighborhoods encompass complex environments comprised of unique economic, physical, and social characteristics that have a profound impact on the residing individual's health and, collectively, on the community's wellbeing. Neighborhood disadvantage (ND) is one of several factors that prominently contributes to racial breast cancer (BC) health disparities in American women. African American (AA) women develop more aggressive breast cancer features, such as triple-negative receptor status and more advanced histologic grade and tumor stage, and suffer worse clinical outcomes than European American (EA) women. While the adverse effects of neighborhood disadvantage on health, including increased risk of cancer and decreased longevity, have recently come into focus, the specific molecular mechanisms by which neighborhood disadvantage increases BC risk and worsens BC outcomes (survivorship, recurrence, mortality) are not fully elucidated. This review illuminates the probable biological links between neighborhood disadvantage and predominantly BC risk, with an emphasis on stress reactivity and inflammation, epigenetics and telomere length in response to adverse neighborhood conditions.

Single cell arrays of hematological cancer cells for assessment of lymphocyte cytotoxicity dynamics, serial killing, and extracellular molecules

Cytotoxicity exerted by cytotoxic lymphocytes against cancer cells is an essential cellular function for successful cancer immunotherapy. Standard cytotoxicity assays mostly provide population level information, whereas live cell imaging-based cytotoxicity assays can assess single cell level heterogeneity. However, long term tracking of individual cytotoxic lymphocyte-hematological cancer cell interactions is technically challenging because both cells can float around and form multi-cellular aggregates. To overcome this limitation, single hematological cancer cell arrays with immobilized hematological cancer cells are fabricated using microwell arrays. Using this new platform, single cell level natural killer (NK) cell cytotoxicity against leukemic cells is quantitatively assessed. Depending on microwell surface adhesiveness and inter-microwell distances, distinct modes of NK-leukemic cell interactions that result in different NK cell cytotoxicity are observed. For microwell arrays coated with bovine serum albumin, which prevents cell adhesion, NK cells stably contacted cancer cells with rounded morphologies, whereas for microwell arrays coated with fibronectin (FN), which triggers integrin signals, NK cells contacting cancer cells exhibited dynamic behaviors with elongated morphologies and constantly explored extracellular spaces by membrane extension. In addition, FN on extracellular spaces facilitate NK cell detachment from leukemic cells after killing by providing anchorage for force transmission, and promote cytotoxicity and serial killing. Single hematologic cell arrays are not only an efficient method for lymphocyte cytotoxicity analysis but also a useful tool to study the role of signaling molecules in extracellular spaces on lymphocyte cytotoxicity.

Tumour biomarkers-Tracing the molecular function and clinical implication

In recent years, with the increase in cancer mortality caused by metastasis, and with the development of individualized and precise medical treatment, early diagnosis with precision becomes the key to decrease the death rate. Since detecting tumour biomarkers in body fluids is the most non‐invasive way to identify the status of tumour development, it has been widely investigated for the usage in clinic. These biomarkers include different expression or mutation in microRNAs (miRNAs), circulating tumour DNAs (ctDNAs), proteins, exosomes and circulating tumour cells (CTCs). In the present article, we summarized and discussed some updated research on these biomarkers. We overviewed their biological functions and evaluated their multiple roles in human and small animal clinical treatment, including diagnosis of cancers, classification of cancers, prognostic and predictive values for therapy response, monitors for therapy efficacy, and anti‐cancer therapeutics. Biomarkers including different expression or mutation in miRNAs, ctDNAs, proteins, exosomes and CTCs provide more choice for early diagnosis of tumour detection at early stage before metastasis. Combination detection of these tumour biomarkers may provide higher accuracy at the lowest molecule combination number for tumour early detection. Moreover, tumour biomarkers can provide valuable suggestions for clinical anti‐cancer treatment and execute monitoring of treatment efficiency.

Salidroside protects ATDC5 cells against lipopolysaccharide-induced injury through up-regulation of microRNA-145 in osteoarthritis

BACKGROUND

Osteoarthritis (OA) is a kind of degenerative disease characterized by the degeneration of the articular cartilage. Salidroside (SAL) is an active component of Rhodiola rosea L., which exhibits diverse pharmacological effects in different diseases. However, the effects of SAL on OA remain largely unclear. The study aimed to investigate the roles of SAL in lipopolysaccharides (LPS)-induced inflammatory injury in murine ATDC5 chondrocyte cells.

METHODS

LPS induced ATDC5 cell injury model was constructed by determining cell viability, apoptosis, apoptosis-associated factors as well as inflammatory cytokines expressions and concentrations. Then, the various concentrations of SAL were used to treat ATDC5 cells, and the effect of SAL on LPS-induce inflammatory injury was detected. After treatment with SAL, the expression level of miR-145 was measured by qRT-PCR. Subsequently, miR-145 inhibitor and corresponding control were transfected into ATDC5 cells to explore the influences of miR-145 in LPS-induce inflammatory injury. Besides, the key signaling pathways of NF-κB and p38MAPK were analyzed by using western blot.

RESULTS

LPS inhibited cell viability, induced apoptosis, activated cleaved-caspase-3/-9 expression, as well as increased IL-6, MCP-1 and TNF-α expressions and secretions in ATDC5 cells. SAL significantly alleviated LPS-induced inflammatory injury. Meanwhile, the expression of miR-145 was up-regulated by SAL. The protective effect of SAL on LPS-induced injury was obviously reversed by miR-145 inhibition. Furthermore, SAL inactivated NF-κB and p38MAPK signaling pathways by regulating miR-145.

CONCLUSIONS

These findings suggested that SAL could protect ATDC5 cells against LPS-induced injury via up-regulation of miR-145 in ATDC5 chondrocyte cells.

β2ARs stimulation in osteoblasts promotes breast cancer cell adhesion to bone marrow endothelial cells in an IL-1β and selectin-dependent manner

Progression and recurrence of breast cancer, as well as reduced survival of patients with breast cancer, are associated with chronic stress, a condition known to impact the hypothalamic-pituitary axis and the autonomic nervous system. Preclinical and clinical evidence support the involvement of the sympathetic nervous system in the control of bone remodeling and in pathologies of the skeleton, including bone metastasis. In experimental mouse models of skeletal metastasis, administration of the βAR agonist isoproterenol (ISO), used as a surrogate of norepinephrine, the main neurotransmitter of sympathetic neurons, was shown to favor bone colonization of metastatic breast cancer cells via an increase bone marrow vascularity. However, successful extravasation of cancer cells into a distant organ is known to be favored by an activated endothelium, itself stimulated by inflammatory signals. Based on the known association between high sympathetic outflow, the expression of inflammatory cytokines and bone metastasis, we thus asked whether βAR stimulation in osteoblasts may alter the vascular endothelium to favor cancer cell engraftment within the skeleton. To address this question, we used conditioned medium (CM) from PBS or ISO-treated bone marrow stromal cells (BMSCs) in adhesion assays with bone marrow endothelial cells (BMECs) or the endothelial cell line C166. We found that ISO treatment in differentiated BMSCs led to a robust induction of the pro-inflammatory cytokines interleukin-1 beta (IL-1β) and interleukin-6 (IL-6). The CM from ISO-treated BMSCs increased the expression of E- and P-selectin in BMECs and the adhesion of human MDA-MB-231 breast cancer cells to these cells in short-term static and dynamic adhesion assays, and a blocking antibody against IL-1β, but not IL-6, reduced this effect. Direct IL-1β treatment of BMECs had a similar effect, whereas the impact of IL-6 treatment on the expression of adhesion molecules by BMECs and on the adhesion of cancer cells to BMECs was negligible. Collectively, these in vitro results suggest that in the context of the multicellular and dynamic bone marrow environment, sympathetic activation and subsequent βAR stimulation in osteoblasts may profoundly remodel the density but also the activation status of bone marrow vessels to favor the skeletal engraftment of circulating breast cancer cells.

•

β2AR activation in osteoblasts increases the expression of pro-inflammatory cytokines IL-1β and IL-6.

•

IL-1β promotes the adhesion of breast cancer cells to endothelium via an endothelial increase in E- and P-selectin expression.

•

IL-1β blockade and selectin inhibition inhibits breast cancer cell adhesion to endothelial cells.

Effect of soluble factors derived from ZR 75.30 breast cancer cells on endothelial activation

In this study, we analyzed soluble factors secreted by two Estrogen Receptor Positive (ER-α) human breast cancer cell lines, ZR 75.30 (luminal B) and MCF7 (luminal A), and evaluated their effect on endothelial activation. The composition of tumoral soluble factors (TSFs) was analyzed by ELISA (Bio-Plex). TSFs from ZR 75.30 cells expressed higher levels of TNF, IFN-γ, IL-6, and IL-8 compared to TSFs from MCF-7 cells. TSFs from ZR 75.30 cells induced a pro-adhesive phenotype in human umbilical vein endothelial cells (HUVECs), as characterized by increased monocytic cell adhesion, adhesion molecule expression and NF-κB activation and decreased IκB-α expression. Conversely, TSFs from MCF-7 cells exerted none of these effects on HUVECs. We then added TNF, IFN-γ, IL-6 or IL-8 alone or in combination with TSFs from MCF-7 cells to HUVECs. Only the combinations that included TNF induced endothelial activation. A neutralizing antibody against IL-1β (this cytokine was not measured in the ELISA) had a modest blocking effect on cellular adhesion or the expression of adhesion molecules induced by TSFs from ZR 75.30 cells in HUVECs. However neutralizing antibodies against TNF, IFN-γ, IL-6 or IL-8 had no effect. Our results suggest that although TNF is an inducer of endothelial cell activation, it is not the only molecule that is responsible for this effect in TSFs from ZR 75.30 cells.

Preclinical and clinical aspects of TNF-α and its receptors TNFR1 and TNFR2 in breast cancer

Breast cancer is the most common malignancy in women and a public health problem worldwide. Breast cancer is often accompanied by an inflammatory process characterized by the presence of proinflammatory cytokines such as tumor necrosis factor (TNF-α), which has important implications in the course of the disease. Inflammation has been described primarily as a favorable environment for tumor development. However, under certain conditions TNF-α can promote signals for activation, differentiation, survival or cell death, so the study of the variants of this cytokine, its receptors, the presence of polymorphisms and its implication in different phenotypes of breast cancer is necessary. Although the clinical application of TNF-α has been limited by its toxicity and side effects, preclinical and clinical studies have shown that these effects may partially be avoided via tumor-targeted delivery strategies. In this manner, TNF-α alone or combined with chemotherapy and radiotherapy can function as an adjuvant in the treatment of breast cancer.

In vitro assays for determining the metastatic potential of melanoma cell lines with characterized in vivo invasiveness

The metastatic potential of cancer cells is an elusive property that is indicative of the later stages of cancer progression. The ability to distinguish between poorly and highly metastatic cells is invaluable for understanding the basic biology of cancer and to develop more treatments. In this paper, we exploit a A375 melanoma cell line series (A375P, A375MA1, A375MA2) that vary in metastatic potential, to demonstrate an in vitro screening assay using polydimethylsiloxane (PDMS) microbubble well arrays that can distinguish these cell lines by their growth characteristics in including morphology, migratory potential, and clonogenic potential. These cell lines cannot be distinguished by their growth characteristics when cultured on standard tissue culture plastic or planar PDMS. Results show that the more metastatic cell lines (A375MA1, A375MA2) have a higher proliferative potential and a distinctive radial spreading growth pattern out of the microbubble well. The A375MA2 cell line also has a higher tendency to form multicellular spheroids. The ability to successfully correlate the metastatic potential of cancer cells with their growth characteristics is essential first step toward developing a high-throughput screening assay to identify aggressive tumor cells in primary samples. The capability to culture and recover aggressive cells from microbubble wells will enable identification of candidate metastatic biomarkers which has immense clinical significance.

Glycophenotype of breast and prostate cancer stem cells treated with thieno[2,3-b]pyridine anticancer compound

Tumor progression may be driven by a small subpopulation of cancer stem cells (CSCs characterized by CD44⁺/CD24⁻ phenotype). We investigated the influence of a newly developed thienopyridine anticancer compound (3-amino-5-oxo-N-naphthyl-5,6,7, 8-tetrahydrothieno[2,3-b]quinoline-2-carboxamide, 1) on the growth, survival and glycophenotype (CD15s and GM3 containing neuraminic acid substituted with acetyl residue, NeuAc) of breast and prostate cancer stem/progenitor-like cell population. MDA-MB-231 and Du-145 cells were incubated with compound 1 alone or in combination with paclitaxel. The cellular metabolic activity was determined by the 3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide (MTT) assay. The type of cell death induced by 48-h treatment was assessed using a combination of Annexin-V-FITC and propidium iodide staining. Flow cytometric analysis was performed to detect the percentage of CD44⁺/CD24⁻ cells, and GM3 and CD15s positive CSCs, as well as the expression of GM3 and CD15s per one CSC, in both cell lines. Compound 1 produces a dose- and time-dependent cytotoxicity, mediated mainly by apoptosis in breast cancer cells, and slightly (2.3%) but statistically significant lowering breast CSC subpopulation. GM3 expression per one breast CSC was increased, and the percentage of prostate GM3⁺ CSC subpopulation was decreased in cells treated with compound 1 compared with non-treated cells. The percentage of CD15s⁺ CSCs was lower in both cell lines after treatment with compound 1. Considering that triple-negative breast cancers are characterized by an increased percentage of breast CSCs and knowing their association with an increased risk of metastasis and mortality, compound 1 is a potentially effective drug for triple-negative breast cancer treatment.

Circulating tumor cell clusters: What we know and what we expect (Review)

The major cause of cancer-associated mortality is tumor metastasis, a disease that is far from understood. Many studies have observed circulating tumor cells (CTCs) in patients' circulation systems, and a few latest investigations showed that CTC clusters have a potentially high capacity of metastasis. The capture and analysis of CTC clusters offer new insights into tumor metastasis and can facilitate the development of cancer treatments. We reviewed the research history of the CTC clusters, as well as the technologies used for detecting and isolating CTC clusters. In addition, we discuss the characteristics of CTC clusters and their roles in tumor dissemination. Clinical relevance of CTC clusters was also implicated in currently limited data. Moving forward, the next frontier in this field is to develop more efficient capture methods and decipher conundrums of characterization of CTC clusters. This will ultimately identify the clinical value of CTC clusters as a biomarker and therapeutic target.

Lapatinib increases motility of triple-negative breast cancer cells by decreasing miRNA-7 and inducing Raf-1/MAPK-dependent interleukin-6

Lapatinib, a dual epidermal growth factor receptor (EGFR) and HER2 tyrosine kinase inhibitor (TKI), has been approved for HER2-positive breast cancer patients. Nevertheless, its inhibitory effect on EGFR did not deliver clinical benefits for triple-negative breast cancer (TNBC) patients even EGFR overexpression was frequently found in this disease. Moreover, lapatinib was unexpectedly found to enhance metastasis of TNBC cells, but the underlying mechanisms are not fully understood. In this study, we explored that the level of interleukin-6 (IL-6) was elevated in lapatinib-treated TNBC cells. Treatment with IL-6 antibody abolished the lapatinib-induced migration. Mechanistically, the signaling axis of Raf-1/mitogen-activated protein kinases (MAPKs), c-Jun N-terminal kinases (JNKs), p38 MAPK, and activator protein 1 (AP-1) was activated in response to lapatinib treatment to induce IL-6 expression. Furthermore, our data showed that microRNA-7 directly binds and inhibits Raf-1 3'UTR activity, and that down-regulation of miR-7 by lapatinib contributes to the activation of Raf-1 signaling pathway and the induction of IL-6 expression. Our results not only revealed IL-6 as a key regulator of lapatinib-induced metastasis, but also explored the requirement of miR7/Raf-1/MAPK/AP-1 axis in lapatinib-induced IL-6 expression.

Comparison of human and mouse E-selectin binding to Sialyl-Lewis(x)

Background

During inflammation, leukocytes are captured by the selectin family of adhesion receptors lining blood vessels to facilitate exit from the bloodstream. E-selectin is upregulated on stimulated endothelial cells and binds to several ligands on the surface of leukocytes. Selectin:ligand interactions are mediated in part by the interaction between the lectin domain and Sialyl-Lewis x (sLe^x), a tetrasaccharide common to selectin ligands. There is a high degree of homology between selectins of various species: about 72 and 60 % in the lectin and EGF domains, respectively. In this study, molecular dynamics, docking, and steered molecular dynamics simulations were used to compare the binding and dissociation mechanisms of sLe^x with mouse and human E-selectin. First, a mouse E-selectin homology model was generated using the human E-selectin crystal structure as a template.

Results

Mouse E-selectin was found to have a greater interdomain angle, which has been previously shown to correlate with stronger binding among selectins. sLe^x was docked onto human and mouse E-selectin, and the mouse complex was found to have a higher free energy of binding and a lower dissociation constant, suggesting stronger binding. The mouse complex had higher flexibility in a few key residues. Finally, steered molecular dynamics was used to dissociate the complexes at force loading rates of 2000–5000 pm/ps². The mouse complex took longer to dissociate at every force loading rate and the difference was statistically significant at 3000 pm/ps². When sLe^x-coated microspheres were perfused through microtubes coated with human or mouse E-selectin, the particles rolled more slowly on mouse E-selectin.

Conclusions

Both molecular dynamics simulations and microsphere adhesion experiments show that mouse E-selectin protein binds more strongly to sialyl Lewis x ligand than human E-selectin. This difference was explained by a greater interdomain angle for mouse E-selectin, and greater flexibility in key residues. Future work could introduce similar amino acid substitutions into the human E-selectin sequence to further modulate adhesion behavior.

Flavonoids as Cytokine Modulators: A Possible Therapy for Inflammation-Related Diseases

High levels of cytokines, such as interleukin (IL)-1β, tumor necrosis factor (TNF)-α and IL-6, are associated with chronic diseases like rheumatoid arthritis, asthma, atherosclerosis, Alzheimer's disease and cancer; therefore cytokine inhibition might be an important target for the treatment of these diseases. Most drugs used to alleviate some inflammation-related symptoms act by inhibiting cyclooxygenases activity or by blocking cytokine receptors. Nevertheless, these drugs have secondary effects when used on a long-term basis. It has been mentioned that flavonoids, namely quercetin, apigenin and luteolin, reduce cytokine expression and secretion. In this regard, flavonoids may have therapeutical potential in the treatment of inflammation-related diseases as cytokine modulators. This review is focused on current research about the effect of flavonoids on cytokine modulation and the description of the way these compounds exert their effect.

Tumor suppressor SET9 guides the epigenetic plasticity of breast cancer cells and serves as an early-stage biomarker for predicting metastasis

During the course of cancer progression, neoplastic cells undergo dynamic and reversible transitions between multiple phenotypic states, and this plasticity is enabled by underlying shifts in epigenetic regulation. Our results identified a negative feedback loop in which SET9 controls DNA methyltransferase-1 protein stability, which represses the transcriptional activity of the SET9 promoter in coordination with Snail. The modulation of SET9 expression in breast cancer cells revealed a connection with E2F1 and the silencing of SET9 was sufficient to complete an epigenetic program that favored epithelial-mesenchymal transition and the generation of cancer stem cells, indicating that SET9 plays a role in modulating breast cancer metastasis. SET9 expression levels were significantly higher in samples from patients with pathological complete remission than in samples from patients with disease recurrence, which indicates that SET9 acts as a tumor suppressor in breast cancer and that its expression may serve as a prognostic marker for malignancy.

Targeting Selectins and Their Ligands in Cancer

Aberrant glycosylation is a hallmark of cancer cells with increased evidence pointing to a role in tumor progression. In particular, aberrant sialylation of glycoproteins and glycolipids has been linked to increased immune cell evasion, drug evasion, drug resistance, tumor invasiveness, and vascular dissemination, leading to metastases. Hypersialylation of cancer cells is largely the result of overexpression of sialyltransferases (STs). Differentially, humans express twenty different STs in a tissue-specific manner, each of which catalyzes the attachment of sialic acids via different glycosidic linkages (α2-3, α2-6, or α2-8) to the underlying glycan chain. One important mechanism whereby overexpression of STs contributes to an enhanced metastatic phenotype is via the generation of selectin ligands. Selectin ligand function requires the expression of sialyl-Lewis X and its structural isomer sialyl-Lewis A, which are synthesized by the combined action of alpha α1-3-fucosyltransferases, α2-3-sialyltransferases, β1-4-galactosyltranferases, and N-acetyl-β-glucosaminyltransferases. The α2-3-sialyltransferases ST3Gal4 and ST3Gal6 are critical to the generation of functional E- and P-selectin ligands and overexpression of these STs have been linked to increased risk of metastatic disease in solid tumors and poor outcome in multiple myeloma. Thus, targeting selectins and their ligands as well as the enzymes involved in their generation, in particular STs, could be beneficial to many cancer patients. Potential strategies include ST inhibition and the use of selectin antagonists, such as glycomimetic drugs and antibodies. Here, we review ongoing efforts to optimize the potency and selectivity of ST inhibitors, including the potential for targeted delivery approaches, as well as evaluate the potential utility of selectin inhibitors, which are now in early clinical development.

Mast Cell Targeted Chimeric Toxin Can Be Developed as an Adjunctive Therapy in Colon Cancer Treatment

The association of colitis with colorectal cancer has become increasingly clear with mast cells being identified as important inflammatory cells in the process. In view of the relationship between mast cells and cancer, we studied the effect and mechanisms of mast cells in the development of colon cancer. Functional and mechanistic insights were gained from ex vivo and in vivo studies of cell interactions between mast cells and CT26 cells. Further evidence was reversely obtained in studies of mast cell targeted Fcε-PE40 chimeric toxin. Experiments revealed mast cells could induce colon tumor cell proliferation and invasion. Cancer progression was found to be related to the density of mast cells in colonic submucosa. The activation of MAPK, Rho-GTPase, and STAT pathways in colon cancer cells was triggered by mast cells during cell-to-cell interaction. Lastly, using an Fcε-PE40 chimeric toxin we constructed, we confirmed the promoting effect of mast cells in development of colon cancer. Mast cells are a promoting factor of colon cancer and thus also a potential therapeutic target. The Fcε-PE40 chimeric toxin targeting mast cells could effectively prevent colon cancer in vitro and in vivo. Consequently, these data may demonstrate a novel immunotherapeutic approach for the treatment of tumors.

Activation of neuroimmune pathways increases therapeutic effects of radiotherapy on poorly differentiated breast carcinoma

Recent studies document the importance of neuronal dysfunction in cancer development and metastasis. We reported previously that both depletion of neuropeptides in capsaicin-sensitive sensory nerve endings and vagotomy increases metastasis of triple negative breast carcinoma. Of the sensory neuropeptides, Substance P (SP) is distributed widely for regulation of immune functions. We therefore examined the affects of continuous exposure to low doses of SP on brain metastatic cells of the mouse breast carcinoma (4TBM) in the presence of radiotherapy (RT) thought to increase antigenicity of cancer cells. 4TBM cells have a cancer stem cell phenotype and induce extensive visceral metastasis after orthotopic inoculation into the mammary pad. Results demonstrated that SP treatment decreases the number of tumor-infiltrating myeloid-derived suppressor cells as well as the TNF-α response to LPS challenge. SP also increased CD4+Cd25(bright) cells in draining lymph nodes of tumor-bearing animals and IFN-γ secretion from leukocyte culture prepared from lymph nodes and spleens of tumor-bearing animals. SP also prevented tumor-induced degeneration of sensory nerve endings and altered release of angiogenic factors from cancer-associated fibroblasts (CAF) and tumor explants. In accordance with these observed immunological effects, combination treatment of continuous SP with a single dose of RT induced complete tumor regression and significantly reduced or prevented metastasis in 50% of the animals while suppressing primary tumor growth and metastasis in the remaining mice. These original findings demonstrate that SP through neuroimmune modulation can prevent formation of immune suppression in the tumor microenvironment, enhance cytotoxic immunity in the presence of RT and prevent metastatic growth.

A physical sciences network characterization of circulating tumor cell aggregate transport

Circulating tumor cells (CTC) have been implicated in the hematogenous spread of cancer. To investigate the fluid phase of cancer from a physical sciences perspective, the multi-institutional Physical Sciences-Oncology Center (PS-OC) Network performed multidisciplinary biophysical studies of single CTC and CTC aggregates from a patient with breast cancer. CTCs, ranging from single cells to aggregates comprised of 2-5 cells, were isolated using the high-definition CTC assay and biophysically profiled using quantitative phase microscopy. Single CTCs and aggregates were then modeled in an in vitro system comprised of multiple breast cancer cell lines and microfluidic devices used to model E-selectin mediated rolling in the vasculature. Using a numerical model coupling elastic collisions between red blood cells and CTCs, the dependence of CTC vascular margination on single CTCs and CTC aggregate morphology and stiffness was interrogated. These results provide a multifaceted characterization of single CTC and CTC aggregate dynamics in the vasculature and illustrate a framework to integrate clinical, biophysical, and mathematical approaches to enhance our understanding of the fluid phase of cancer.

Targeted killing of metastatic cells using a platelet-inspired drug delivery system

Pro-metastatic tumor cells in circulation interact with active platelets that mediate various mechanisms of hematologic metastasis. Elucidating and utilizing these interactions on delivery vehicles can provide unique ways of metastasis-targeted drug delivery.

TRAIL-mediated apoptosis in breast cancer cells cultured as 3D spheroids

TNF-alpha-related-apoptosis-inducing-ligand (TRAIL) has been explored as a therapeutic drug to kill cancer cells. Cancer cells in the circulation are subjected to apoptosis-inducing factors. Despite the presence of these factors, cells are able to extravasate and metastasize. The homotypic and heterotypic cell-cell interactions in a tumor are known to play a crucial role in bestowing important characteristics to cancer cells that leave the primary site. Spheroid cell culture has been extensively used to mimic these physiologically relevant interactions. In this work, we show that the breast cancer cell lines BT20 and MCF7, cultured as 3D tumor spheroids, are more resistant to TRAIL-mediated apoptosis by downregulating the expression of death receptors (DR4 and DR5) that initiate TRAIL-mediated apoptosis. For comparison, we also investigated the effect of TRAIL on cells cultured as a 2D monolayer. Our results indicate that tumor spheroids are enriched for CD44^hiCD24^loALDH1^hi cells, a phenotype that is predominantly known to be a marker for breast cancer stem cells. Furthermore, we attribute the TRAIL-resistance and cancer stem cell phenotype observed in tumor spheroids to the upregulation of cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE₂) pathway. We show that inhibition of the COX-2/PGE₂ pathway by treating tumor spheroids with NS-398, a selective COX-2 inhibitor, reverses the TRAIL-resistance and decreases the incidence of a CD44^hiCD24^lo population. Additionally, we show that siRNA mediated knockdown of COX-2 expression in MCF7 cells render them sensitive to TRAIL by increasing the expression of DR4 and DR5. Collectively, our results show the effect of the third-dimension on the response of breast cancer cells to TRAIL and suggest a therapeutic target to overcome TRAIL-resistance.

Bidirectional effect of CD200 on breast cancer development and metastasis, with ultimate outcome determined by tumor aggressiveness and a cancer-induced inflammatory response

CD200 acts through its receptor (CD200R) to inhibit excessive inflammation. The role of CD200-CD200R1 interaction in tumor immunity is poorly understood. In this study, we examined the role of CD200-CD200R1 interaction in the progression and metastasis of highly aggressive 4THM murine-breast carcinoma using CD200 transgenic (CD200(tg)) and CD200R1 knock-out (CD200R1(-)(/-)) BALB/c mice. 4THM cells induce extensive visceral metastasis and neutrophil infiltration in affected tissues. CD200 overexpression in the host was associated with decreased primary tumor growth and metastasis, whereas lack of CD200R1 expression by host cells was associated with enhanced visceral metastasis. Absence of CD200R1 expression led to decreased tumor-infiltrating-cytotoxic T cells and increased the release of inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and interleukin (IL)-6. In contrast, CD200 overexpression led to increased tumor-induced interferon-γ and IL-10 response and decreased TNF-α and IL-6 release. Neutrophil infiltration of tissues was markedly decreased in CD200(tg) animals and increased in CD200R1(-/-) mice. These findings are contradictory to what has been reported in the EMT6 mouse breast-cancer model. Other distinguishing features of tumor elicited by EMT6 and 4THM cell injections were also examined. Visceral tissues from mice bearing EMT6 tumors showed a lack of neutrophil infiltration and decreased IL-6 release in CD200R1(-/-) mice. EMT6 and 4THM cells also differed in vimentin expression and in vitro migration rate, which was markedly lower in EMT6 tumors. These results support the hypothesis that CD200 expression can alter immune responses, and can inhibit metastatic growth of tumor cells that induce systemic and local inflammatory response. Increasing CD200 activity/signaling might be an important therapeutic strategy for treatment of aggressive breast carcinomas.

TLRs: linking inflammation and breast cancer

Breast cancer is one of the leading causes of mortality in the females. Intensive efforts have been made to understand the molecular mechanisms of pathogenesis of breast cancer. The physiological conditions that lead to tumorigenesis including breast cancer are not well understood. Toll like receptors (TLRs) are essential components of innate immune system that protect the host against bacterial and viral infection. The emerging evidences suggest that TLRs are activated through pathogen associated molecular patterns (PAMPs) as well as endogenous molecules, which lead to the activation of inflammatory pathways. This leads to increased levels of several pro-inflammatory cytokines and chemokines mounting inflammation. Several evidences support the view that chronic inflammation can lead to cancerous condition. Inflammation aids in tumor progression and metastasis. Association of inflammation with breast cancer is emerging. TLR mediated activation of NF-κB and IRF is an essential link connecting inflammation to cancer. The recent reports provide several evidences, which suggest the important role of TLRs in breast cancer pathogenesis and recurrence. The current review focuses on emerging studies suggesting the strong linkages of TLR mediated regulation of inflammation during breast cancer and its metastasis emphasizing the initiation of the systematic study.

Towards a molecular basis of oligometastatic disease: potential role of micro-RNAs

Oligometastasis is a cancer disease state characterized by a limited number of metastatic tumors involving single or few organs and with biological properties that make them potentially amenable to locoregional antitumor therapy. Current clinical data show that they are potentially curable with surgical resection or/and radiotherapy. Yet, mechanisms of progression from primary tumor to oligometastasis, rather than to polymetastases, is lacking in detail. In the current review we focus on the role of micro-RNAs in the regulation of metastases development and the role they may play in the differentiation of oligometastatic from polymetastatic progression. We also discuss the analyses of metastatic samples from oligo-and polymetastatic patients, which suggest that oligometastasis is a distinct biologic entity regulated in part by micro-RNAs. In addition, a review of the known functions of oligometastatic-specific micro-RNAs suggest that they regulate multiple steps in the metastatic cascade, including epithelial–mesenchymal transition, tumor invasion, intravasation, distant vascular extravasation and proliferation in a distant organ. Understanding the role of micro-RNAs and their target genes in oligometastatic disease may allow for the development of targeted therapies to effectively conrol the spread of metastases.