14q32-encoded microRNAs mediate an oligometastatic phenotype

[Oligometastases and oligoprogressions: Concepts and natural history]

The oligometastatic paradigm refers to an intermediate biologic state of cancer with restricted metastatic capacity. Its phenotype is characterized by a limited number of metastases and a slow tumor growth. Various clinical and pre-clinical studies associated this state to alterations of the biological mechanisms involved in metastatic diffusion. Eventually, this transitional state leads to a wide metastatic dissemination. However, there is a period during which the patient could benefit from local ablative treatment. Depending on several prognostic factors and the treatment provided, long survival or even healing can sometimes be achieved. The selection of patients eligible for such a curative strategy may be adapted following clinical, radiological or biological markers. Recent improvement of therapeutic and imaging are changing the clinical definition of oligometastatic cancer, which should be adapted to evidence from recent clinical and preclinical data.

Tumor biology and multidisciplinary strategies of oligometastasis in gastrointestinal cancers

More than 70% of gastrointestinal (GI) cancers are diagnosed with metastases, leading to poor prognosis. For some cancer patients with limited sites of metastatic tumors, the term oligometastatic disease (OMD) has been coined as opposed to systemic polymetastasis (PMD) disease. Stephan Paget first described an organ-specific pattern of metastasis in 1889, now known as the "seed and soil" theory where distinct cancer types are found to metastasize to different tumor-specific sites. Our understanding of the biology of tumor metastasis and specifically the molecular mechanisms driving their formation are still limited, in particular, as it relates to the genesis of oligometastasis. In the following review, we discuss recent advances in general understanding of this metastatic behavior including the role of specific signaling pathways, various molecular features and biomarkers, as well as the interaction of carcinoma cells with their tissue microenvironments (both primary and metastatic niches). The unique features that underlie OMD provide potential targets for localized therapy. As it relates to clinical practice, OMD is emerging as treatable with surgical resection and/or other local therapy options. Strategies currently being applied in the clinical management of OMD will be discussed including surgical, radiation-based therapy, ablation procedures, and the results of emerging clinical trials involving immunotherapy.

Stereotactic ablative radiotherapy for the comprehensive treatment of 4-10 oligometastatic tumors (SABR-COMET-10): study protocol for a randomized phase III trial

Background

Stereotactic ablative radiotherapy (SABR) has emerged as a new treatment option for patients with oligometastatic disease. SABR delivers precise, high-dose, hypofractionated radiotherapy, and achieves excellent rates of local control for primary tumors or metastases. A recent randomized phase II trial evaluated SABR in a group of patients with a small burden of oligometastatic disease (mostly with 1–3 metastatic lesions), and found that SABR was associated with benefits in progression-free survival and overall survival. The goal of this phase III trial is to assess the impact of SABR in patients with 4–10 metastatic cancer lesions.

Methods

One hundred and fifty-nine patients will be randomized in a 1:2 ratio between the control arm (consisting of standard of care palliative-intent treatments), and the SABR arm (consisting of standard of care treatment + SABR to all sites of known disease). Randomization will be stratified by two factors: histology (Group 1: prostate, breast, or renal; Group 2: all others), and type of pre-specified systemic therapy (Group 1: immunotherapy/targeted; Group 2: cytotoxic; Group 3: observation). SABR is to be completed within 2 weeks, allowing for rapid initiation of systemic therapy. Recommended SABR doses are 20 Gy in 1 fraction, 30 Gy in 3 fractions, or 35 Gy in 5 fractions, chosen to minimize risks of toxicity. The primary endpoint is overall survival, and secondary endpoints include progression-free survival, time to development of new metastatic lesions, quality of life, and toxicity. Translational endpoints include assessment of circulating tumor cells, cell-free DNA, and tumor tissue as prognostic and predictive markers, including assessment of immunological predictors of response and long-term survival.

Discussion

This study will provide an assessment of the impact of SABR on clinical outcomes and quality of life, to determine if long-term survival can be achieved for selected patients with 4–10 oligometastatic lesions.

Trial registration

Clinicaltrials.gov identifier: NCT03721341. Date of registration: October 26, 2018.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5977-6) contains supplementary material, which is available to authorized users.

Liquid Biopsy in Oligometastatic Prostate Cancer-A Biologist's Point of View

Prostate cancer (PCa) is the main cause of cancer-related mortality in males and the diagnosis, treatment, and care of these patients places a great burden on healthcare systems globally. Clinically, PCa is highly heterogeneous, ranging from indolent tumors to highly aggressive disease. In many cases treatment-generally either radiotherapy (RT) or surgery-can be curative. Several key genetic and demographic factors such as age, family history, genetic susceptibility, and race are associated with a high incidence of PCa. While our understanding of PCa, which is mainly based on the tools of molecular biology-has improved dramatically in recent years, efforts to better understand this complex disease have led to the identification of a new type of PCa-oligometastatic PCa. Oligometastatic disease should be considered an individual, heterogeneous entity with distinct metastatic phenotypes and, consequently, wide prognostic variability. In general, patients with oligometastatic disease typically present less biologically aggressive tumors whose metastatic potential is more limited and which are slow-growing. These patients are good candidates for more aggressive treatment approaches. The main aim of the presented review was to evaluate the utility of liquid biopsy for diagnostic purposes in PCa and for use in monitoring disease progression and treatment response, particularly in patients with oligometastatic PCa. Liquid biopsies offer a rapid, non-invasive approach whose use t is expected to play an important role in routine clinical practice to benefit patients. However, more research is needed to resolve the many existing discrepancies with regard to the definition and isolation method for specific biomarkers, as well as the need to determine the most appropriate markers. Consequently, the current priority in this field is to standardize liquid biopsy-based techniques. This review will help to improve understanding of the biology of PCa, particularly the recently defined condition known as "oligometastatic PCa". The presented review of the body of evidence suggests that additional research in molecular biology may help to establish novel treatments for oligometastatic PCa. In the near future, the treatment of PCa will require an interdisciplinary approach involving active cooperation among clinicians, physicians, and biologists.

Systemic miRNA delivery by nontoxic nanoscale coordination polymers limits epithelial-to-mesenchymal transition and suppresses liver metastases of colorectal cancer

Though early detection and treatment of primary tumors has significantly improved in recent years, metastatic disease remains among the most significant challenges in cancer therapy. Cancer cells can disseminate before the primary tumor is detected to form micro or gross metastases, requiring toxic systemic therapies. To prevent and suppress metastases, we have developed a nontoxic, long-circulating nanoscale coordination polymer (NCP) protecting microRNA (miRNA) in circulation and releasing it in tumors. PtIV(en)2 [en = ethylenediamine] containing NCPs (PtEN) can release a nontoxic, kinetically inert PtII(en)2 compound and carbon dioxide which aids the endosomal escape of its miRNA cargo, miR-655-3p. Without the presence of the PtEN core, the miRNA showed cellular uptake but no effect. When transfected into human colorectal HCT116 cells by NCPs, this oligometastatic miRNA limited proliferation and epithelial-to-mesenchymal transition by preventing β-catenin nuclear translocation and tumor cell invasion. Systemic administrations of PtEN/miR-655-3p sustained effective transfection to reduce liver colonization and tumor burden in a xenogenic hepatic metastatic model of HCT116 without any observable toxicity.

Dual Epigenetic Regulation of ERα36 Expression in Breast Cancer Cells

Breast cancer remains the major cause of cancer-induced morbidity and mortality in women. Among the different molecular subtypes, luminal tumors yet considered of good prognosis often develop acquired resistance to endocrine therapy. Recently, misregulation of ERα36 was reported to play a crucial role in this process. High expression of this ERα isoform was associated to preneoplastic phenotype in mammary epithelial cells, disease progression, and enhanced resistance to therapeutic agents in breast tumors. In this study, we identified two mechanisms that could together contribute to ERα36 expression regulation. We first focused on hsa-miR-136-5p, an ERα36 3’UTR-targeting microRNA, the expression of which inversely correlated to the ERα36 one in breast cancer cells. Transfection of hsa-miR136-5p mimic in MCF-7 cells resulted in downregulation of ERα36. Moreover, the demethylating agent decitabine was able to stimulate hsa-miR-136-5p endogenous expression, thus indirectly decreasing ERα36 expression and counteracting tamoxifen-dependent stimulation. The methylation status of ERα36 promoter also directly modulated its expression level, as demonstrated after decitabine treatment of breast cancer cell and confirmed in a set of tumor samples. Taken together, these results open the way to a direct and an indirect ERα36 epigenetic modulation by decitabine as a promising clinical strategy to counteract acquired resistance to treatment and prevent relapse.

miR-655-3p inhibits cell migration and invasion by targeting pituitary tumor-transforming 1 in non-small cell lung cancer

miR-655-3p functions as a tumor suppressor in tumor metastases; however, its role and mechanism in regulating cell migration and invasion of non-small cell lung cancer (NSCLC) remain unclear. Here, we found that miR-655-3p expression was markedly decreased in the NSCLC cell lines A549, NCI-H1650, PC14/b, NCI-H1299, and HPAEpiC compared to levels observed in normal human lung fibroblasts. miR-655-3p overexpression significantly inhibited migration and invasion of A549 and PC14/b cells, and pituitary tumor-transforming 1 (PTTG1) expression was up-regulated in the NSCLC cells. Luciferase reporter assays indicated that PTTG1 was a direct target of miR-655-3p. Additionally, PTTG1 overexpression alleviated the inhibitory effect of miR-655-3p on migration and invasion abilities in A549 and PC14/b cells. In conclusion, miR-655-3p inhibits NSCLC migration and invasion by targeting PTTG1, suggesting that miR-655-3p may serve as a therapeutic target to provide a new approach for the clinical treatment of NSCLC.

DNA Methylation Controls Metastasis-Suppressive 14q32-Encoded miRNAs

Expression of 14q32-encoded miRNAs is a favorable prognostic factor in patients with metastatic cancer. In this study, we used genomic inhibition of DNA methylation through disruption of DNA methyltransferases DNMT1 and DNMT3B and pharmacologic inhibition with 5-Aza-2'-deoxycytidine (5-Aza-dC, decitabine) to demonstrate that DNA methylation predominantly regulates expression of metastasis-suppressive miRNAs in the 14q32 cluster. DNA demethylation facilitated CCCTC-binding factor (CTCF) recruitment to the maternally expressed gene 3 differentially methylated region (MEG3-DMR), which acts as a cis-regulatory element for 14q32 miRNA expression. 5-Aza-dC activated demethylation of the MEG3-DMR and expression of 14q32 miRNAs, which suppressed adhesion, invasion, and migration (AIM) properties of metastatic tumor cells. Cancer cells with MEG3-DMR hypomethylation exhibited constitutive expression of 14q32 miRNAs and resistance to 5-Aza-dC-induced suppression of AIM. Expression of methylation-dependent 14q32 miRNAs suppressed metastatic colonization in preclinical models of lung and liver metastasis and correlated with improved clinical outcomes in patients with metastatic cancer. These findings implicate epigenetic modification via DNA methylation in the regulation of metastatic propensity through miRNA networks and identify a previously unrecognized action of decitabine on the activation of metastasis-suppressive miRNAs. SIGNIFICANCE: This study investigates epigenetic regulation of metastasis-suppressive miRNAs and the effect on metastasis.

Stereotactic Radiotherapy for Oligometastasis

Oligometastatic disease is defined as “a condition with a few metastases arising from tumors that have not acquired a potential for widespread metastases.” Its behavior suggests a transitional malignant state somewhere between localized and metastatic cancer. Treatment of oligometastatic disease is expected to achieve long-term local control and to improve survival. Historically, patients with oligometastases have often undergone surgical resection since it was anecdotally believed that surgical resection could result in progression-free or overall survival benefits. To date, no prospective randomized trials have demonstrated surgery-related survival benefits. Short courses of highly focused, extremely high-dose radiotherapies (e.g., stereotactic radiosurgery and stereotactic ablative body radiotherapy (SABR)) have frequently been used as alternatives to surgery for treatment of oligometastasis. A randomized study has demonstrated the overall survival benefits of stereotactic radiosurgery for solitary brain metastasis. Following the success of stereotactic radiosurgery, SABR has been widely accepted for treating extracranial metastases, considering its efficacy and minimum invasiveness. In this review, we discuss the history of and rationale for the local treatment of oligometastases and probe into the implementation of SABR for oligometastatic disease.

Oligometastatic prostate cancer: Reality or figment of imagination?

The term “oligometastatic prostate cancer” refers to a heterogeneous group of disease states currently defined solely on the basis of clinical features. Oligorecurrent disease, de novo oligometastases, and oligoprogressive disease likely have unique biologic underpinnings and natural histories. Evidence suggesting the existence of a subset of patients who harbor prostate cancer with limited metastatic potential currently includes disparate and overwhelmingly retrospective reports. Nevertheless, emerging prospective data have corroborated the “better‐than‐expected,” retrospectively observed outcomes, particularly in the setting of oligorecurrent prostate cancer. Improved functional imaging with prostate‐specific membrane antigen‐targeted strategies may enhance the identification of patients with oligometastatic prostate cancer in the short term. In the long term, refinement of the oligometastatic case definition likely will require biologic risk‐stratification schemes. To determine optimal treatment strategies and identify patients most likely to benefit from metastasis‐directed therapy, future efforts should focus on conducting high‐quality, prospective trials with much‐needed molecular correlative studies.

The term “oligometastatic prostate cancer” currently refers to a heterogeneous group of clinically defined disease states. To improve patient risk stratification and determine optimal treatment strategies, future efforts should focus on conducting prospective trials and determining a biologic categorization of patients with limited metastatic potential.

The 46th David A. Karnofsky Memorial Award Lecture: Oligometastasis—From Conception to Treatment

Metastasis from most adult solid tumors generally has been considered to be widespread and incurable. Here, I present clinical and molecular data to support the hypothesis that some metastases are limited in number and pace and are curable with ablative therapies. I advance the hypothesis that immunotherapy combined with radiotherapy may be a general strategy to increase the number of patients with metastatic cancer amenable to cure. I further suggest that, in the context of ablative radiotherapy, the potential synergies between immunotherapy and radiotherapy are principally within the local tumor microenvironment and require treatment of all or most sites of metastatic disease. Improvements in the molecular staging of metastasis, immunotherapy strategies, and radiotherapy delivery are likely to improve outcomes for patients with metastatic cancer.

A risk-based approach to identifying oligometastatic disease on imaging

Recognition of <3 metastases in <2 organs, particularly in cancers with a known predisposition to oligometastatic disease (OMD) (colorectal, prostate, renal, sarcoma and lung), offers the opportunity to focally treat the lesions identified and confers a survival advantage. The reliability with which OMD is identified depends on the sensitivity of the imaging technique used for detection and may be predicted from phenotypic and genetic factors of the primary tumour, which determine metastatic risk. Whole‐body or organ‐specific imaging to identify oligometastases requires optimization to achieve maximal sensitivity. Metastatic lesions at multiple locations may require a variety of imaging modalities for best visualisation because the optimal image contrast is determined by tumour biology. Newer imaging techniques used for this purpose require validation. Additionally, rationalisation of imaging strategies is needed, particularly with regard to timing of imaging and follow‐up studies. This article reviews the current evidence for the use of imaging for recognising OMD and proposes a risk‐based roadmap for identifying patients with true OMD, or at risk of metastatic disease likely to be OM.

Stereotactic ablative radiation therapy for oligometastatic prostate cancer delays time-to-next systemic treatment

PURPOSE

Local ablative treatment to oligometastatic patients can result in long-term disease-free survival in some cancer patients. The importance of this treatment paradigm in prostate cancer is a rapidly evolving field. Herein, we report on the safety and preliminary clinical outcomes of a modern cohort of oligometastatic prostate cancer (OPC) patients treated with consolidative stereotactic ablative radiation (SABR).

METHODS

Records of men with OPC who underwent consolidative SABR at our institution were reviewed. SABR was delivered in 1-5 fractions of 5-18 Gray. Kaplan-Meier estimates of local progression-free survival (LPFS), biochemical progression-free survival (bPFS; PSA nadir + 2), distant progression-free survival (DPFS), and time-to-next intervention (TTNI) were calculated.

RESULTS

In total, 66 OPC patients were identified with consolidative SABR delivered to 134 metastases: 89 bone, 40 nodal, and 5 viscera. The majority of men (49/66) had hormone-sensitive prostate cancer (HSPC). Crude grade 1 and 2 acute toxicities were 36% and 11%, respectively, with no ≥ grade 3 toxicity. At 1 year, LPFS was 92% and bPFS and DPFS were 69%. Of the 18 men with HSPC who had deferred hormone therapy , 11 (56%) remain disease free following SABR (1-year ADT-FS was 78%). In 17 castration-resistant men, 11 had > 50% prostate-specific antigen (PSA) declines with 1-year TTNI of 30%.

CONCLUSIONS

Consolidative SABR in OPC is feasible and well tolerated. The heterogeneity and small size of our series limit extrapolation of clinically meaningful outcomes following consolidative SABR in OPC, but our preliminary data suggest that this approach warrants continued prospective study.

Cure in metastatic breast cancer

Oligometastatic disease characterizes a distinct subgroup of metastatic breast cancer patients that might benefit from different treatment strategies to achieve long-lasting remission and potentially cure. Those long-lasting remissions are reported after locoregional treatment of the primary tumor and all metastatic sites in several case series; however, unlike other tumor entities, prospective data are lacking. Furthermore, tumor eradication by excellent systemic anticancer therapy with novel chemotherapies and targeted agents can lead to long-term survival. In addition, reactivation of the host immune defense by immuno-oncologic drugs can achieve long-lasting tumor control. So far, unfortunately, checkpoint inhibitors as monotherapy have led to responses only in a small percentage of patients with metastatic breast cancer. This short review summarizes available data on long-lasting remissions and potential cure in metastatic breast cancers. It describes and discusses data on locoregional treatment, chemo-, antibody- and immunotherapy and tries to select individual patients for whom a multidisciplinary treatment approach with curative intention might be an option to achieve long-term survival.

The biology of prostate cancer metastases: does oligo differ from polymetastatic?

PURPOSE OF REVIEW

To examine the studies of prostate cancer biology, which evaluated oligometastatic and polymetastatic disease to identify data supporting differences between them.

RECENT FINDINGS

Studies of tumor biology suggest that malignant cells of limited metastatic potential exist, which may explain the phenomenon of oligometastatic disease. Conversely, oligometastatic disease may represent earlier presentation of polymetastatic disease in a proportion of cases. Data suggest molecular differences between oligo and polymetastatic disease, although larger studies are required to validate these results. Micro RNA differences between oligo and polymetastatic disease appear especially intriguing, which may regulate gene expression and modulate metastatic potential.

SUMMARY

Although metastatic prostate cancer is traditionally treated by systemic therapy alone, the concept of oligometastatic disease prompting ablative therapy of metastases is emerging. Better understanding of the molecular alterations driving oligometastatic disease may help tailor therapy for these patients, by helping discriminate between true oligometastatic disease and disease destined to progress to polymetastatic status.

Integrated molecular subtyping defines a curable oligometastatic state in colorectal liver metastasis

The oligometastasis hypothesis suggests a spectrum of metastatic virulence where some metastases are limited in extent and curable with focal therapies. A subset of patients with metastatic colorectal cancer achieves prolonged survival after resection of liver metastases consistent with oligometastasis. Here we define three robust subtypes of de novo colorectal liver metastasis through integrative molecular analysis. Patients with metastases exhibiting MSI-independent immune activation experience the most favorable survival. Subtypes with adverse outcomes demonstrate VEGFA amplification in concert with (i) stromal, mesenchymal, and angiogenic signatures, or (ii) exclusive NOTCH1 and PIK3C2B mutations with E2F/MYC activation. Molecular subtypes complement clinical risk stratification to distinguish low-risk, intermediate-risk, and high-risk patients with 10-year overall survivals of 94%, 45%, and 19%, respectively. Our findings provide a framework for integrated classification and treatment of metastasis and support the biological basis of curable oligometastatic colorectal cancer. These concepts may be applicable to many patients with metastatic cancer.

Approach to oligometastatic disease in head and neck cancer, on behalf of the GORTEC

Median survival for recurrent/metastatic head and neck squamous cell cancer (HNSCC) patients is about 10 months after first-line best systemic treatment. We aimed to assess current approaches of oligometastatic HNSCC patients by the analysis of current concept and published data (1995–2017) in this population. Five-year survival rates are over 20% in selected patients who undergo metastasis-directed therapy by either surgery or stereotactic irradiation. Human papillomavirus(+) HNSCC patients have more disseminated metastases but respond more favorably and also benefit from ablative treatments. Treatments of oligometastases are expanding rapidly. Unmet needs include revised imaging follow-up strategies to detect metastases earlier, identification of predictive noninvasive biomarkers for treatment guidance, assessment and corrections of biases in current studies and randomized clinical trials.

Stereotactic ablative body radiation for oligometastatic and oligoprogressive disease

Stage IV non-small cell lung cancer (NSCLC) exists on a spectrum, with a subset of patients presenting with oligometastatic disease involving only a limited number of distant sites. For these patients, local consolidative therapy (LCT) has been demonstrated to improve outcomes through ablation or cytoreduction of metastatic disease, as shown in an increasing number of randomized controlled trials. In particular, stereotactic ablative body radiation (SABR) has emerged as a feasible treatment modality for elimination of oligometastatic sites. This focused review examines the underlying biologic mechanisms and clinical data in support of SABR in the setting of oligometastatic NSCLC. Following a comprehensive evaluation of the pertinent retrospective, prospective, and anticipated trials to date, we summarize the evidence regarding patient selection, treatment safety, and technical considerations to provide guidance of this approach for clinicians.

Stereotactic Body Radiotherapy for Oligometastasis: Opportunities for Biology to Guide Clinical Management

Oligometastasis refers to a state of limited metastatic disease burden, in which surgical or ablative treatment to all known visible metastases holds promise to extend survival or even effect cure. Stereotactic body radiotherapy is a form of radiation treatment capable of delivering a high biologically effective dose of radiation in a highly conformal manner, with a favorable toxicity profile. Enthusiasm for oligometastasis ablation, however, should be counterbalanced against the limited supporting evidence. It remains unknown to what extent (if any) ablation influences survival or quality of life. Rising clinical equipoise necessitates the completion of randomized controlled trials to assess this, several of which are underway. However, a lack of clear identification criteria or biomarkers to define the oligometastatic state hampers optimal patient selection.This narrative review explores the evolutionary origins of oligometastasis, the steps of the metastatic process at which oligometastases may arise, and the biomolecular mediators of this state. It discusses clinical outcomes with treatment of oligometastases, ongoing trials, and areas of basic and translational research that may lead to novel biomarkers. These efforts should provide a clearer, biomolecular definition of oligometastatic disease and aid in the accurate selection of patients for ablative therapies.

In Vivo Delivery and Therapeutic Effects of a MicroRNA on Colorectal Liver Metastases

Multiple therapeutic agents are typically used in concert to effectively control metastatic tumors. Recently, we described microRNAs that are associated with the oligometastatic state, in which a limited number of metastatic tumors progress to more favorable outcomes. Here, we report the effective delivery of an oligometastatic microRNA (miR-655-3p) to colorectal liver metastases using nanoscale coordination polymers (NCPs). The NCPs demonstrated a targeted and prolonged distribution of microRNAs to metastatic liver tumors. Tumor-targeted microRNA miR-655-3p suppressed tumor growth when co-delivered with oxaliplatin, suggesting additive or synergistic interactions between microRNAs and platinum drugs. This is the first known example of systemically administered nanoparticles delivering an oligometastatic microRNA to advanced metastatic liver tumors and demonstrating tumor-suppressive effects. Our results suggest a potential therapeutic strategy for metastatic liver disease by the co-delivery of microRNAs and conventional cytotoxic agents using tumor-specific NCPs.

A sketch of known and novel MYCN-associated miRNA networks in neuroblastoma

Neuroblastoma (NB) originates from neural crest-derived precursors and represents the most common childhood extracranial solid tumour. MicroRNAs (miRNAs), a class of small non-coding RNAs that participate in a wide variety of biological processes by regulating gene expression, appear to play an essential role within the NB context. High-throughput next generation sequencing (NGS) was applied to study the miRNA transcriptome in a cohort of NB tumours with and without MYCN-amplification (MNA and MNnA, respectively) and in dorsal root ganglia (DRG), as a control. Out of the 128 miRNAs differentially expressed in the NB vs. DRG comparison, 47 were expressed at higher levels, while 81 were expressed at lower levels in the NB tumours. We also found that 23 miRNAs were differentially expressed in NB with or without MYCN-amplification, with 17 miRNAs being upregulated and 6 being downregulated in the MNA subtypes. Functional annotation analysis of the target genes of these differentially expressed miRNAs demonstrated that many mRNAs were involved in cancer-related pathways, such as DNA-repair and apoptosis as well as FGFR and EGFR signalling. In particular, we found that miR-628-3p negatively affects MYCN gene expression. Furthermore, we identified a novel miRNA candidate with variable expression in MNA vs. MNnA tumours, whose putative target genes are implicated in the mTOR pathway. The present study provides further insight into the molecular mechanisms that correlate miRNA dysregulation to NB development and progression.

Percutaneous CT-guided radiofrequency ablation for patients with extrahepatic oligometastases of hepatocellular carcinoma: long-term results

BACKGROUND

The aim of this study was to evaluate the therapeutic outcome of percutaneous computed tomography (CT)-guided radiofrequency ablation (RFA) for extrahepatic oligometastases of hepatocellular carcinoma (HCC).

METHODS

Institutional review board approval was obtained for this retrospective study, and all patients provided written informed consent. Between April 2004 and December 2015, 116 oligometastases (diameter, 5-50 mm; 20.3 ± 10.4) in 79 consecutive HCC patients (73 men and 6 women; average age, 50.3 years ±13.0) were treated with RFA. We focussed on patients with 1-3 extrahepatic metastases (EHM) confined to 1-2 organs (including the lung, adrenal gland, bone, lymph node and pleura/peritoneum) who were treated naïve with curative intent. Survival, technical success and safety were evaluated. The log-rank test and Cox proportional hazards regression models were used to analyse the survival data.

RESULTS

No immediate technical failure occurred, and at 1 month, the technique effectiveness rate was determined to be 95.8%. After a median follow-up time of 28.0 months (range, 6-108 months), the 1-, 2- and 3-year overall survival (OS) rates were 91, 70 and 48%, respectively, with a median survival time of 33.5 months. Time to unoligometastatic progression (TTUP) of less than 6 months (p < 0.001) and a Child-Pugh score of more than 5 (p = 0.001) were significant indicators of shorter OS. The 1-, 2- and 3-year disease free survival (DFS) rates were 34, 21 and 8%, respectively, with a median DFS time of 6.8 months. DFS was better for those with lung metastases (p = 0.006). Major complication occurred in nine (9.5%, 9/95) RFA sessions without treatment-related mortality.

CONCLUSIONS

CT-guided RFA for oligometastatic HCC may provide favourable efficacy and technical success with a minimally invasive approach.

Surgery in oligometastatic NSCLC patients in the targeted therapy era

More than 50% of NSCLC patients present with metastatic disease at first diagnosis, with a median survival of 8-11 months. However, selected patients with oligometastatic disease who receive appropriate local therapy for both the primary lesion and metastases enjoy long-term survival or are even cured. The new (eighth) edition of the tumor, node and metastasis classification of lung cancer suggests that patients with a single metastatic lesion in one distant organ should be placed into a new category, M1b, which will certainly lead to more applications of local therapy in such subpopulations. Moreover, as the applications of targeted therapy increase, surgery will play an evermore critical role in eliminating drug-resistant cancer clones of patients who exhibit mixed responses to tyrosine kinase inhibitors. The lung, brain and adrenal gland are the most common oligometastatic organs, and are reviewed separately.

Resection of Large Metachronous Liver Metastasis with Gastric Origin: Case Report and Review of the Literature

INTRODUCTION

Increasing evidence suggests that surgical resection may be offered to a subgroup of patients with liver metastasis of gastric adenocarcinoma. The aim of this case report is to illustrate the surgical resection of a single liver metachronous recurrence twelve months after a radical total gastrectomy for cancer.

CASE REPORT

A 63-year-old male patient with an Eastern Cooperative Oncology Group performance status of 1 was referred to our hospital for a single, large liver metastasis, twelve months after a radical total gastrectomy and DII lymphadenectomy for upper third gastric adenocarcinoma. As the adjuvant treatment, the patient received 12 cycles of FOLFOX chemotherapy. During the present admission, the abdominal computed tomography (CT) revealed a single liver metastasis located in the segments 5 and 6, of 105/85 mm in diameter. Surgical resection by an open approach of liver metastasis was decided. We performed a non-anatomical liver resection, without inflow control due to significant peritoneal adhesions in the liver hilum secondary to the previous lymphadenectomy. The patient was discharged after seven days, with an uneventful recovery. Six months after the second surgical procedure, the patient developed a local liver recurrence. The surgical resection of the liver recurrence was performed, with no postoperative morbidities, and the patient was discharged after eight days. Three months after the latest surgery, the patient is under adjuvant chemotherapy, with no imagistic signs of further recurrences.

CONCLUSIONS

  Hepatic resection for liver metastasis of gastric origin may offer satisfactory oncological outcomes in a very selected subgroup of patients.

Metastatic breast cancer: The Odyssey of personalization

Metastatic breast cancer is the most frequent cause of cancer death for women worldwide. In the last 15 years, a large number of new agents have entered clinical use, a result of the dramatic increase in our understanding of the molecular underpinnings of metastatic breast cancer. However, while these agents have led to better outcomes, they are also at the root cause of increasing financial pressure on healthcare systems. Moreover, decision making in an era where every year new agents are added to the therapeutic armamentarium has also become a significant challenge for medical oncologists. In the present article, we will provide an ample review on the most recent developments in the field of treatment of the different subtypes of metastatic breast cancer with a critical discussion on the slow progress made in identifying response biomarkers. New hopes in the form of ctDNA monitoring and functional imaging will be presented.

Imaging oligometastatic cancer before local treatment

With the advent of novel treatment strategies to help widen the therapeutic window for patients with oligometastatic cancer, improved biomarkers are needed to reliably define patients who can benefit from these treatments. Multimodal imaging is one such option and should be optimised to comprehensively assess metastatic sites, disease burden, and response to neoadjuvant treatment in each disease setting. These features will probably remain important prognostic biomarkers, and are crucial in planning multidisciplinary treatment. There are opportunities to extract additional phenotypic information from conventional imaging, while novel imaging techniques can also reveal specific aspects of tumour biology. Imaging can both characterise and localise the phenotypic heterogeneity of multiple tumour sites. Novel approaches to existing imaging datasets and correlation with tumour biology will be important in realising the potential of imaging to guide treatment in the oligometastatic setting. In this Personal View, we discuss the current status and future directions of imaging before treatment in patients with extracranial oligometastases.

MicroRNA-544a Regulates Migration and Invasion in Colorectal Cancer Cells via Regulation of Homeobox A10

BACKGROUND/AIMS

MicroRNAs (miRNAs) are a group of small RNA molecules that post-transcriptionally regulate gene expression. Aberrant expression of miRNAs has been associated with tumorigenesis in various cancers. miR-544a is an understudied miRNA that has recently been implicated in regulating invasion in lung cancer. However, its role in regulating invasion and the underlying mechanism have not been investigated in colorectal cancer (CRC) cells.

METHODS

Microarray analysis was performed in metastatic colorectal tumor samples and their matched normal tissues to identify differentially expressed miRNAs. Quantitative real-time PCR was used to detect miR-544a levels in tumor samples and CRC cell lines with varying metastatic properties. miR-544a mimic or inhibitor was transfected into SW480 and HCT116 cells, respectively, followed by wound healing and invasion assays. Western Blot and luciferase assay were performed to investigate the direct target of miR-544a. Xenograft mouse models was used to examine in vivo function of miR-544a.

RESULTS

Our data showed that expression of miR-544a was significantly up-regulated in metastatic tumor samples and CRC cell lines. Inhibition of miR-544a reduced migration and invasion in HCT116 cells. Homeobox A10 (HOXA10) was the direct target of miR-544a which was required for the function of miR-544a in regulating invasiveness. miR-544a inhibitor and/or HOXA10 overexpression reduced lung metastases in HCT116 xenografts.

CONCLUSIONS

Our study demonstrates that miR-544a regulates invasive and metastatic properties of CRC cells by modulating HOXA10 expression level both in vitro and in vivo. miR-544a may represent a new therapeutic target for the intervention of metastatic colorectal cancer.

Patterns of Distant Metastases After Surgical Management of Non-Small-cell Lung Cancer

BACKGROUND

Patients with limited metastases, oligometastases (OMs), might have improved outcomes compared with patients with widespread distant metastases (DMs). The incidence and behavior of OMs from non-small-cell lung cancer (NSCLC) need further characterization.

PATIENTS AND METHODS

The medical records of patients who had undergone surgery for stage I-III NSCLC from 1995 to 2009 were retrospectively reviewed. All information pertaining to development of the first metastatic progression was recorded and analyzed. Patients with DMs were categorized into OMs (1-3 lesions potentially amenable to local therapy) and DM subgroups.

RESULTS

Of 1719 patients reviewed, 368 (21%) developed DMs with a median follow-up period of 39 months. A single lesion was diagnosed in 115 patients (31%) and 69 (19%) had 2 to 3 lesions (50% oligometastatic). The median survival from the DM diagnosis for oligometastatic and diffuse DM was 12.4 and 6.1 months, respectively (hazard ratio, 0.54; 95% confidence interval, 0.42-0.68; P < .001). Patients with a single metastasis had the longest median survival at 14.7 months. Younger age, OM, the use of chemotherapy for the primary tumor, and DM detection by surveillance imaging were independently associated with improved survival.

CONCLUSION

DMs and OMs are common in surgically managed NSCLC. Overall survival appears to be prolonged with OM.

Ablative Approaches for Pulmonary Metastases

Pulmonary metastases are common in patients with cancer for which surgery is considered a standard approach in appropriately selected patients. A number of patients are not candidates for surgery due to a medical comorbidities or the extent of surgery required. For these patients, noninvasive or minimally invasive approaches to ablate pulmonary metastases are potential treatment strategies. This article summarizes the rationale and outcomes for non-surgical treatment approaches, including radiotherapy, radiofrequency and microwave ablation, for pulmonary metastases.

MicroRNA-154 inhibits growth and invasion of breast cancer cells through targeting E2F5

Accumulating evidence suggested that microRNA-154 (miR-154) might play important roles in the development of various cancer types. However, the role of miR-154 in breast cancer progression remains largely unknown. Here, miR-154 expression level was measured via quantitative real-time RT-PCR (qRT-PCR) in 36 pairs of human breast cancer tissues and adjacent normal breast tissues and in a panel of human breast cancer cell lines. Cell proliferation, cycle, migration, and invasion were assessed by CCK8 assay, flow cytometer assay, wound healing assay and transwell invasion assay, respectively. Luciferase reporter assay and Western blot was used to verify E2F transcription factor 5 protein (E2F5) as a novel target gene of miR-154. Our results showed that miR-154 was frequently downregulated in breast cancer tissues and cell lines. Overexpression of miR-154 in MCF-7 cells significantly inhibited cell proliferation, migration, and invasion, and increased cell arrest at G0/G1 stage in vitro. E2F5 was identified as a target of miR-154, and its expression was inversely correlated with miR-154 expression in clinical breast cancer tissues. In addition, downregulation of E2F5 in MCF7 cells had similar effect on cell proliferation, cycle, migration and invasion by miR-154 induced. These findings indicate that miR-154 acts as a tumor suppressor by targeting E2F5, suggesting miR-154 as a potential therapeutic target for the treatment of breast cancer.

MicroRNA-655-3p functions as a tumor suppressor by regulating ADAM10 and β-catenin pathway in Hepatocellular Carcinoma

BACKGROUND

Increasing evidence suggests that microRNAs (miRNAs) play critical roles in malignant transformation, tumor progression and metastasis. Aberrant miR-655-3p expression has been associated with several cancers. However, the role and underlying mechanism of miR-655-3p in the development of hepatocellular carcinoma (HCC) remains unclear.

METHODS

MiR-655-3p expression was detected by quantitative RT-PCR (qRT-PCR) in human HCC tissues and cell lines. Cell proliferation was investigated using MTT and colony formation assays, and cell migration and invasion abilities were evaluated by transwell assay. ADAM10 protein expression was detected by immunohistochemical assay. The target gene and downstream of miR-655-3p were determined by qRT-PCR, western blot and dual-luciferase reporter assays.

RESULTS

miR-655-3p was significantly down-regulated in HCC tissues and HCC cell lines. Low miR-655-3p expression was negatively related to tumor size, portal vein tumor thrombosis (PVTT) status, TNM stage and metastasis status. In addition, miR-655-3p overexpression and depletion decreased and increased HCC cell proliferation, migration and invasion, respectively. Moreover, ADAM10 was identified as a direct target of miR-655-3p, and miR-655-3p down-regulated E-cadherin protein level and inhibits β-catenin pathway by mediating ADAM10.

CONCLUSIONS

MiR-655-3p might functions as a tumor suppressor by directly targeting ADAM10 and indirectly regulating β-catenin pathway in the development of progression of HCC. It may be a novel therapeutic candidate target to in HCC treatment.

Clinical and molecular markers of long-term survival after oligometastasis-directed stereotactic body radiotherapy (SBRT)

BACKGROUND

The selection of patients for oligometastasis-directed ablative therapy remains a challenge. The authors report on clinical and molecular predictors of survival from a stereotactic body radiotherapy (SBRT) dose-escalation trial for oligometastases.

METHODS

Patients who had from 1 to 5 metastases, a life expectancy of >3 months, and a Karnofsky performance status of >60 received escalating SBRT doses to all known cancer sites. Time to progression, progression-free survival, and overall survival (OS) were calculated at the completion of SBRT, and clinical predictors of OS were modeled. Primary tumor microRNA expression was analyzed to identify molecular predictors of OS.

RESULTS

Sixty-one evaluable patients were enrolled from 2004 to 2009. The median follow-up was 2.3 years for all patients (range, 0.2-9.3 years) and 6.8 years for survivors (range, 2.0-9.3 years). The median, 2-year, and 5-year estimated OS were 2.4 years, 57%, and 32%, respectively. The rate of progression after SBRT was associated with an increased risk of death (hazard ratio [HR], 1.44; 95% confidence interval [CI], 1.24-1.82). The time from initial cancer diagnosis to metastasis (HR, 0.98; 95% CI, 0.98-0.99), the time from metastasis to SBRT (HR, 0.98; 95% CI, 0.98-0.99), and breast cancer histology (HR, 0.12; 95% CI, 0.07-0.37) were significant predictors of OS. In an exploratory analysis, a candidate classifier using expression levels of 3 microRNAs (miR-23b, miR-449a, and miR-449b) predicted survival among 17 patients who had primary tumor microRNA expression data available.

CONCLUSIONS

A subset of oligometastatic patients achieves long-term survival after metastasis-directed SBRT. Clinical features and primary tumor microRNA expression profiling, if validated in an independent dataset, may help select oligometastatic patients most likely to benefit from metastasis-directed therapy. Cancer 2016;122:2242-50. © 2016 American Cancer Society.

Unique microRNAs appear at different times during the course of a delayed-type hypersensitivity reaction in human skin

Diphencyprone (DPCP) is a hapten that induces delayed-type hypersensitivity (DTH) reactions. MicroRNAs (miRNAs) are short non-coding RNAs that negatively regulate gene expression and have been implicated in various inflammatory skin diseases, but their role in DTH reactions is not well understood. We generated global miRNA expression profiles (using next-generation sequencing) of DPCP reactions in skin of seven healthy volunteers at 3, 14 and 120 days after challenge. Compared to placebo-treated sites, DPCP-challenged skin at 3 days (peak inflammation) had 127 miRNAs significantly deregulated. At 14 days (during resolution of inflammation), 43 miRNAs were deregulated and, at 120 days (when inflammation had completely resolved), six miRNAs were upregulated. While some miRNAs have been observed in psoriasis or atopic dermatitis, most of the deregulated miRNAs have not yet been studied in the context of skin biology or immunology. Across the three time points studied, many but not all miRNAs were uniquely expressed. As various miRNAs may influence T cell activation, this may indicate that the miRNAs exclusively expressed at different time points function to promote or resolve skin inflammation, and therefore, may inform on the paradoxical ability of DPCP to treat both autoimmune conditions (alopecia areata) and conditions of ineffective immunity (melanoma).

Imaging of tumor clones with differential liver colonization

We present a model of hepatic colorectal metastases which represents monoclonal cell lines double-labeled by luciferase and tdTomato. These cells form liver metastasis in varying numbers and patterns similar to those observed in patients. Using in vivo and ex vivo luminescent and fluorescent imaging we determine the growth kinetics and clonogenic frequency of tumor cells colonizing liver. Molecular profiling detected stable expressional differences between clones consistent with their phenotypes. The data indicate that clinically relevant phenotypes of liver metastases can be modeled in vivo.

Oncogenic CXCL10 signalling drives metastasis development and poor clinical outcome

Background:

The CXCL10/CXCR3 signalling mediates paracrine interactions between tumour and stromal cells that govern leukocyte trafficking and angiogenesis. Emerging data implicate noncanonical CXCL10/CXCR3 signalling in tumourigenesis and metastasis. However, little is known regarding the role for autocrine CXCL10/CXCR3 signalling in regulating the metastatic potential of individual tumour clones.

Methods:

We performed transcriptomic and cytokine profiling to characterise the functions of CXCL10 and CXCR3 in tumour cells with different metastatic abilities. We modulated the expression of the CXCL10/CXCR3 pathway using shRNA-mediated silencing in both in vitro and in vivo models of B16F1 melanoma. In addition, we examined the expression of CXCL10 and CXCR3 and their associations with clinical outcomes in clinical data sets derived from over 670 patients with melanoma and colon and renal cell carcinomas.

Results:

We identified a critical role for autocrine CXCL10/CXCR3 signalling in promoting tumour cell growth, motility and metastasis. Analysis of publicly available clinical data sets demonstrated that coexpression of CXCL10 and CXCR3 predicted an increased metastatic potential and was associated with early metastatic disease progression and poor overall survival.

Conclusion:

These findings support the potential for CXCL10/CXCR3 coexpression as a predictor of metastatic recurrence and point towards a role for targeting of this oncogenic axis in the treatment of metastatic disease.

The biology and treatment of oligometastatic cancer

Clinical reports of limited and treatable cancer metastases, a disease state that exists in a transitional zone between localized and widespread systemic disease, were noted on occasion historically and are now termed oligometastasis. The ramification of a diagnosis of oligometastasis is a change in treatment paradigm, i.e. if the primary cancer site (if still present) is controlled, or resected, and the metastatic sites are ablated (surgically or with radiation), a prolonged disease-free interval, and perhaps even cure, may be achieved. Contemporary molecular diagnostics are edging closer to being able to determine where an individual metastatic deposit is within the continuum of malignancy. Preclinical models are on the outset of laying the groundwork for understanding the oligometastatic state. Meanwhile, in the clinic, patients are increasingly being designated as having oligometastatic disease and being treated owing to improved diagnostic imaging, novel treatment options with the potential to provide either direct or bridging therapy, and progressively broad definitions of oligometastasis.