Cancer is a key health issue across the world, causing substantial patient morbidity and mortality. Patient prognosis is tightly linked with metastatic dissemination of the disease to distant sites, with metastatic diseases accounting for a vast percentage of cancer patient mortality. While advances in this area have been made, the process of cancer metastasis and the factors governing cancer spread and establishment at secondary locations is still poorly understood. The current article summarizes recent progress in this area of research, both in the understanding of the underlying biological processes and in the therapeutic strategies for the management of metastasis. This review lists the disruption of E-cadherin and tight junctions, key signaling pathways, including urokinase type plasminogen activator (uPA), phosphatidylinositol 3-kinase/v-akt murine thymoma viral oncogene (PI3K/AKT), focal adhesion kinase (FAK), β-catenin/zinc finger E-box binding homeobox 1 (ZEB-1) and transforming growth factor beta (TGF-β), together with inactivation of activator protein-1 (AP-1) and suppression of matrix metalloproteinase-9 (MMP-9) activity as key targets and the use of phytochemicals, or natural products, such as those from Agaricus blazei, Albatrellus confluens, Cordyceps militaris, Ganoderma lucidum, Poria cocos and Silybum marianum, together with diet derived fatty acids gamma linolenic acid (GLA) and eicosapentanoic acid (EPA) and inhibitory compounds as useful approaches to target tissue invasion and metastasis as well as other hallmark areas of cancer. Together, these strategies could represent new, inexpensive, low toxicity strategies to aid in the management of cancer metastasis as well as having holistic effects against other cancer hallmarks.

Targeted therapies and the consequent adoption of "personalized" oncology have achieved notable successes in some cancers; however, significant problems remain with this approach. Many targeted therapies are highly toxic, costs are extremely high, and most patients experience relapse after a few disease-free months. Relapses arise from genetic heterogeneity in tumors, which harbor therapy-resistant immortalized cells that have adopted alternate and compensatory pathways (i.e., pathways that are not reliant upon the same mechanisms as those which have been targeted). To address these limitations, an international task force of 180 scientists was assembled to explore the concept of a low-toxicity "broad-spectrum" therapeutic approach that could simultaneously target many key pathways and mechanisms. Using cancer hallmark phenotypes and the tumor microenvironment to account for the various aspects of relevant cancer biology, interdisciplinary teams reviewed each hallmark area and nominated a wide range of high-priority targets (74 in total) that could be modified to improve patient outcomes. For these targets, corresponding low-toxicity therapeutic approaches were then suggested, many of which were phytochemicals. Proposed actions on each target and all of the approaches were further reviewed for known effects on other hallmark areas and the tumor microenvironment. Potential contrary or procarcinogenic effects were found for 3.9% of the relationships between targets and hallmarks, and mixed evidence of complementary and contrary relationships was found for 7.1%. Approximately 67% of the relationships revealed potentially complementary effects, and the remainder had no known relationship. Among the approaches, 1.1% had contrary, 2.8% had mixed and 62.1% had complementary relationships. These results suggest that a broad-spectrum approach should be feasible from a safety standpoint. This novel approach has potential to be relatively inexpensive, it should help us address stages and types of cancer that lack conventional treatment, and it may reduce relapse risks. A proposed agenda for future research is offered.

MiRNAs are master regulators of gene expression that play key roles in cancer metastasis. During bone metastasis, metastatic tumor cells must rewire their biology and express genes that are normally expressed by bone cells (a process called osteomimicry), which endow tumor cells with full competence for outgrowth in the bone marrow. Here, we establish miR-30 family members miR-30a, miR-30b, miR-30c, miR-30d, and miR-30e as suppressors of breast cancer bone metastasis that regulate multiple pathways, including osteomimicry. Low expression of miR-30 in primary tumors from patients with breast cancer were associated with poor relapse-free survival. In addition, estrogen receptor (ER)-negative/progesterone receptor (PR)-negative breast cancer cells expressed lower miR-30 levels than their ER/PR-positive counterparts. Overexpression of miR-30 in ER/PR-negative breast cancer cells resulted in the reduction of bone metastasis burden in vivo. In vitro, miR-30 did not affect tumor cell proliferation, but did inhibit tumor cell invasion. Furthermore, overexpression of miR-30 restored bone homeostasis by reversing the effects of tumor cell–conditioned medium on osteoclastogenesis and osteoblastogenesis. A number of genes associated with osteoclastogenesis stimulation (IL8, IL11), osteoblastogenesis inhibition (DKK-1), tumor cell osteomimicry (RUNX2, CDH11), and invasiveness (CTGF, ITGA5, ITGB3) were identified as targets for repression by miR-30. Among these genes, silencing CDH11 or ITGA5 in ER-/PR-negative breast cancer cells recapitulated inhibitory effects of miR-30 on skeletal tumor burden in vivo. Overall, our findings provide evidence that miR-30 family members employ multiple mechanisms to impede breast cancer bone metastasis and may represent attractive targets for therapeutic intervention. Significance: These findings suggest miR-30 family members may serve as an effective means to therapeutically attenuate metastasis in triple-negative breast cancer. Cancer Res; 78(18); 5259–73. ©2018 AACR.

Receptor activator of NFkB (RANK), its ligand (RANKL) and the decoy receptor of RANKL (osteoprotegerin, OPG) play a pivotal role in bone remodeling by regulating osteoclasts formation and activity. RANKL stimulates migration of RANK-expressing tumor cells in vitro, conversely inhibited by OPG. We examined mRNA expression levels of RANKL/RANK/OPG in a publicly available microarray dataset of 295 primary breast cancer patients. We next analyzed RANK expression by immunohistochemistry in an independent series of 93 primary breast cancer specimens and investigated a possible association with clinicopathological parameters, bone recurrence and survival. Microarray analysis showed that lower RANK and high OPG mRNA levels correlate with longer overall survival (P = 0.0078 and 0.0335, respectively) and disease-free survival (P = 0.059 and 0.0402, respectively). Immunohistochemical analysis of RANK showed a positive correlation with the development of bone metastases (P = 0.023) and a shorter skeletal disease-free survival (SDFS, P = 0.037). Specifically, univariate analysis of survival showed that “RANK-negative” and “RANK-positive” patients had a SDFS of 105.7 months (95% CI: 73.9–124.4) and 58.9 months (95% CI: 34.7–68.5), respectively. RANK protein expression was also associated with accelerated bone metastasis formation in a multivariate analysis (P = 0.029). This is the first demonstration of the role of RANK expression in primary tumors as a predictive marker of bone metastasis occurrence and SDFS in a large population of breast cancer patients.

We conducted a large, multicenter, retrospective survey aimed to explore the impact of tumor bone involvement in Non-Small Cell Lung Cancer.Data on clinical-pathology, skeletal outcomes and bone-directed therapies for 661 deceased patients with evidence of bone metastasis were collected and statistically analyzed. Bone metastases were evident at diagnosis in 57.5% of patients. In the remaining cases median time to bone metastases appearance was 9 months. Biphosphonates were administered in 59.6% of patients. Skeletal-related events were experienced by 57.7% of patients; the most common was the need for radiotherapy. Median time to first skeletal-related event was 6 months. Median survival after bone metastases diagnosis was 9.5 months and after the first skeletal-related event was 7 months. We created a score based on four factors used to predict the overall survival from the diagnosis of bone metastases: age >65 years, non-adenocarcinoma histology, ECOG Performance Status >2, concomitant presence of visceral metastases at the bone metastases diagnosis. The presence of more than two of these factors is associated with a worse prognosis.This study demonstrates that patients affected by Non-Small Cell Lung Cancer with bone metastases represent a heterogeneous population in terms of risk of skeletal events and survival.

Cetuximab (IMC-C225, Erbitux ImClone Systems Inc, New York, NY) is a recombinant, human/mouse chimeric monoclonal antibody (MAb) that binds specifically to the extracellular domain of the human epidermal growth factor receptor (EGFR) on both normal and tumor cells, and competitively inhibits the binding of epidermal growth factor (EGF) as well as other ligands. Cetuximab binding to the EGFR blocks phosphorylation and activation of receptor-associated kinases and their associated downstream signalling (MAPK, PI3K/Akt, Jak/Stat pathways) resulting in inhibition of many cellular processes such as induction of apoptosis, cell growth, decreased Matrix Metallo-Proteinase (MMPs) and vascular endothelial growth factor (VEGF) production. Cetuximab is also able to display cytotoxic effect through antibody-dependent cellular cytotoxicity (ADCC). In vitro and in vivo experiments elucidated a wide range of biological properties attributed to cetuximab, these include: direct inhibition of EGFR tyrosine kinase activity, inhibition of cell cycle progression, inhibition of angiogenesis, invasion and metastatization processes, activation of pro-apoptotic molecules and synergic cytotoxicity effect with chemotherapy and radiotherapy. Several studies have shown cetuximab is able to inhibit growth of EGFR-expressing tumor cells in vitro as well as in nude mice bearing xenografts of human cancer cell lines. Moreover, numerous clinical trials demonstrated cetuximab efficacy in different tumor types and it is approved by Food and Drugs Administration (FDA) for use in the treatment of metastatic colorectal cancer (mCRC) as single agent or in combination with chemotherapy, for locally/regionally advanced head and neck squamous cell carcinoma (HNSCC) in combination with radiotherapy, and as monotherapy for recurrent/metastatic HNSCC after failing platinum-based chemotherapy. This review will illustrate pre-clinical and clinical data on biological properties of cetuximab focusing on the predictive markers of clinical response to this drug.