Towards an International Consensus on the Prevention, Treatment, and Management of High-Risk Substance Use and Overdose among Youth.

Background and Objectives: Now more than ever, there is an obvious need to reduce the overall burden of disease and risk of premature mortality that are associated with mental health and substance use disorders among young people. However, the current state of research and evidence-based clinical care for high-risk substance use among youth is fragmented and scarce. The objective of the study is to establish consensus for the prevention, treatment, and management of high-risk substance use and overdose among youth (10 to 24 years old). Materials and Methods: A modified Delphi technique was used based on the combination of scientific evidence and clinical experience of a group of 31 experts representing 10 countries. A semi-structured questionnaire with five domains (clinical risks, target populations, intervention goals, intervention strategies, and settings/expertise) was shared with the panelists. Based on their responses, statements were developed, which were subsequently revised and finalized through three iterations of feedback. Results: Among the five major domains, 60 statements reached consensus. Importantly, experts agreed that screening in primary care and other clinical settings is recommended for all youth, and that the objectives of treating youth with high-risk substance use are to reduce harm and mortality while promoting resilience and healthy development. For all substance use disorders, evidence-based interventions should be available and should be used according to the needs and preferences of the patient. Involuntary admission was the only topic that did not reach consensus, mainly due to its ethical implications and resulting lack of comparable evidence. Conclusions: High-risk substance use and overdoses among youth have become a major challenge. The system's response has been insufficient and needs substantial change. Internationally devised consensus statements provide a first step in system improvement and reform.

Evidence of epithelial to mesenchymal transition associated with increased tumorigenic potential in an immortalized normal prostate epithelial cell line.

BACKGROUND: The majority of established human prostate cancer cell lines are derived from metastatic lesions and are already tumorigenic in vivo, therefore immortalized normal prostate cell lines may provide a more relevant model to unveil the mechanisms associated with cancer progression and metastasis. METHODS: PZ-HPV-7, an immortalized human prostate epithelial cell line was used to generate xenograft tumors in mice. A subline designated HPV-PZ-7T was subsequently derived from the subrenal capsule xenograft of a nude mouse. These cells were further characterized using karyotyping, immunofluorescence, qRT-PCR, Western blotting, and three-dimensional cultures in Matrigel. RESULTS: The PZ-HPV-7 cell line possesses a typical epithelial morphology, expresses basal cell markers, and is capable of forming web-like structures with evidence of budding on Matrigel. PZ-HPV-7 is non-tumorigenic in immunocompromised mice by either subcutaneous injection or subrenal grafting. In contrast, the PZ-HPV-7T cells, derived from a xenograft tumor induced by co-inoculation with matrigel using subrenal grafting, possess a mesenchymal phenotype as well as luminal cell markers and are highly tumorigenic and metastatic in nude mice. Functionally and biochemically, the PZ-HPV-7T subline appears to have undergone an epithelial-to-mesenchymal transition (EMT) from the parental PZ-HPV-7 line. CONCLUSION: We have developed a novel EMT model using an immortalized normal prostate epithelial cell line and generated a new prostate cancer cell line, PZ-HPV-7T, which may represent an excellent system to study mechanisms associated with prostate cancer progression and metastasis.

The telomerase antagonist, imetelstat, efficiently targets glioblastoma tumor-initiating cells leading to decreased proliferation and tumor growth.

PURPOSE: Telomerase activity is one of the hallmarks of cancer and is a highly relevant therapeutic target. The effects of a novel human telomerase antagonist, imetelstat, on primary human glioblastoma (GBM) tumor-initiating cells were investigated in vitro and in vivo. EXPERIMENTAL DESIGN: Tumor-initiating cells were isolated from primary GBM tumors and expanded as neurospheres in vitro. The GBM tumor-initiating cells were treated with imetelstat and examined for the effects on telomerase activity levels, telomere length, proliferation, clonogenicity, and differentiation. Subsequently, mouse orthotopic and subcutaneous xenografts were used to assess the in vivo efficacy of imetelstat. RESULTS: Imetelstat treatment produced a dose-dependent inhibition of telomerase (IC(50) 0.45 micromol/L). Long-term imetelstat treatment led to progressive telomere shortening, reduced rates of proliferation, and eventually cell death in GBM tumor-initiating cells. Imetelstat in combination with radiation and temozolomide had a dramatic effect on cell survival and activated the DNA damage response pathway. Imetelstat is able to cross the blood-brain barrier in orthotopic GBM xenograft tumors. Fluorescently labeled GBM tumor cells isolated from orthotopic tumors, following systemic administration of imetelstat (30 mg/kg every day for three days), showed approximately 70% inhibition of telomerase activity. Chronic systemic treatment produced a marked decrease in the rate of xenograft subcutaneous tumor growth. CONCLUSION: This preclinical study supports the feasibility of testing imetelstat in the treatment of GBM patients, alone or in combination with standard therapies.

The effects of telomerase inhibition on prostate tumor-initiating cells.

Prostate cancer is the most common malignancy in men, and patients with metastatic disease have poor outcome even with the most advanced therapeutic approaches. Most cancer therapies target the bulk tumor cells, but may leave intact a small population of tumor-initiating cells (TICs), which are believed to be responsible for the subsequent relapse and metastasis. Using specific surface markers (CD44, integrin alpha(2)beta(1) and CD133), Hoechst 33342 dye exclusion, and holoclone formation, we isolated TICs from a panel of prostate cancer cell lines (DU145, C4-2 and LNCaP). We have found that prostate TICs have significant telomerase activity which is inhibited by imetelstat sodium (GRN163L), a new telomerase antagonist that is currently in Phase I/II clinical trials for several hematological and solid tumor malignancies. Prostate TICs telomeres were of similar average length to the telomeres of the main population of cells and significant telomere shortening was detected in prostate TICs as a result of imetelstat treatment. These findings suggest that telomerase inhibition therapy may be able to efficiently target the prostate TICs in addition to the bulk tumor cells, providing new opportunities for combination therapies.

Prostate tumor-initiating cells: a new target for telomerase inhibition therapy?

Conventional therapies for prostate cancer, especially in its androgen-independent form, may result in the survival of small populations of resistant cells with tumor-initiating potential. These "cancer stem cells" are believed to be responsible for cancer relapse, and therapeutic strategies targeting these cells are of great importance. Telomerase is a ribonucleoprotein enzyme responsible for telomere elongation and is activated in the majority of malignancies, including prostate cancer, but is absent in most normal cells. Putative tumor-initiating cells have significant levels of telomerase, indicating that they are an excellent target for telomerase inhibition therapy. In this review, we present some evidence for the hypothesis that conventional therapies (standard chemotherapy and/or radiation therapy) in combination with telomerase inhibitors may result in effective and more durable responses.