Potential Role of Selenium in the Treatment of Cancer and Viral Infections.

Selenium has been extensively evaluated clinically as a chemopreventive agent with variable results depending on the type and dose of selenium used. Selenium species are now being therapeutically evaluated as modulators of drug responses rather than as directly cytotoxic agents. In addition, recent data suggest an association between selenium base-line levels in blood and survival of patients with COVID-19. The major focus of this mini review was to summarize: the pathways of selenium metabolism; the results of selenium-based chemopreventive clinical trials; the potential for using selenium metabolites as therapeutic modulators of drug responses in cancer (clear-cell renal-cell carcinoma (ccRCC) in particular); and selenium usage alone or in combination with vaccines in the treatment of patients with COVID-19. Critical therapeutic targets and the potential role of different selenium species, doses, and schedules are discussed.

Active surveillance of metastatic renal cell carcinoma: Results from a prospective observational study (MaRCC).

BACKGROUND: Systemic therapy (ST) can be deferred in patients who have metastatic renal cell carcinoma (mRCC) and slow-growing metastases. Currently, this subset of patients managed with active surveillance (AS) is not well described in the literature. METHODS: This was a prospective observational study of patients with mRCC across 46 US community and academic centers. The objective was to describe baseline characteristics and demographics of patients with mRCC initially managed by AS, reasons for AS, and patient outcomes. Descriptive statistics were used to characterize demographics, baseline characteristics, and patient-related outcomes. Wilcoxon 2-sample rank-sum tests and χ2 tests were used to assess differences between ST and AS cohorts in continuous and categorical variables, respectively. Kaplan-Meier survival curves were used to assess survival. RESULTS: Of 504 patients, mRCC was initially managed by AS (n = 143) or ST (n = 305); 56 patients were excluded from the analysis. Disease was present in 69% of patients who received AS, whereas the remaining 31% had no evidence of disease. At data cutoff, 72 of 143 patients (50%) in the AS cohort had not received ST. The median overall survival was not reached (95% CI, 122 months to not estimable) in patients who received AS versus 30 months (95% CI, 25-44 months) in those who received ST. Quality of life at baseline was significantly better in patients who were managed with AS versus ST. CONCLUSIONS: AS occurs frequently (32%) in real-world clinical practice and appears to be a safe and appropriate alternative to immediate ST in selected patients.

Understanding the Redox Biology of Selenium in the Search of Targeted Cancer Therapies.

Selenium (Se) is an essential trace nutrient required for optimal human health. It has long been suggested that selenium has anti-cancer properties. However, clinical trials have shown inconclusive results on the potential of Se to prevent cancer. The suggested role of Se in the prevention of cancer is centered around its role as an antioxidant. Recently, the potential of selenium as a drug rather than a supplement has been uncovered. Selenium compounds can generate reactive oxygen species that could enhance the treatment of cancer. Transformed cells have high oxidative distress. As normal cells have a greater capacity to meet oxidative challenges than tumor cells, increasing the flux of oxidants with high dose selenium treatment could result in cancer-specific cell killing. If the availability of Se is limited, supplementation of Se can increase the expression and activities of Se-dependent proteins and enzymes. In cell culture, selenium deficiency is often overlooked. We review the importance of achieving normal selenium biology and how Se deficiency can lead to adverse effects. We examine the vital role of selenium in the prevention and treatment of cancer. Finally, we examine the properties of Se-compounds to better understand how each can be used to address different research questions.

Durable Clinical Benefit in Patients with Advanced Cutaneous Melanoma after Discontinuation of Anti-PD-1 Therapies Due to Immune-Related Adverse Events.

INTRODUCTION: Anti-PD-1 therapies, pembrolizumab and nivolumab, are currently the standard of care for treatment of patients with metastatic melanoma. Treatment is usually continued until toxicity or disease progression. Though these therapies are well tolerated, some patients discontinue them due to immune-related adverse events (irAE). Discontinuation of therapy brings challenges to their management due to limited treatment options and lack of long-term prognostic information for these patients. Herein, we reviewed patients at our institution to analyze their clinical outcomes. MATERIALS AND METHODS: Charts of 1264 consecutive patients enrolled between 8/1/2012 and 7/31/2017 at Melanoma Skin & Ocular Tissue Repositories at Holden Comprehensive Cancer Center at the University of Iowa Hospitals and Clinic were reviewed. Eligible patients were those who received single-agent anti-PD-1 therapy and subsequently discontinued it due to irAE. Reviewed data included patient demographics, prior medical history, baseline disease parameters, and outcomes. Kaplan-Meier survival analysis was done to determine progression-free survival (PFS) and overall survival (OS). RESULTS: Overall 169 patients with advanced, unresectable, or metastatic cutaneous melanoma received anti-PD-1 therapy of which 16 (9.5%) white, non-Hispanic patients with median age of 64.5 (range 35 to 81 years) discontinued treatment due to irAE. Fifteen patients received pembrolizumab and one received nivolumab. The median duration of treatment was 4.7 (range 0.7 to 11.5) months. Median follow-up was 30.3 (range 4.6 to 49.4) months. Median PFS was 24.6 months and median OS was not reached. Durable clinical benefit (time to progression or next treatment of more than 6 months from last treatment) was observed in 13 (81.2%) patients. At the time of analysis, 8 patients had progressed and 4 patients died (all-cause). DISCUSSION: Our results suggest that advanced melanoma patients discontinuing anti-PD-1 therapy due to irAE usually experience durable clinical benefit. However, caution is needed with these agents in patients with underlying autoimmune diseases.

Current Landscape and the Potential Role of Hypoxia-Inducible Factors and Selenium in Clear Cell Renal Cell Carcinoma Treatment.

In the last two decades, the discovery of various pathways involved in renal cell carcinoma (RCC) has led to the development of biologically-driven targeted therapies. Hypoxia-inducible factors (HIFs), angiogenic growth factors, von Hippel⁻Lindau (VHL) gene mutations, and oncogenic microRNAs (miRNAs) play essential roles in the pathogenesis and drug resistance of clear cell renal cell carcinoma. These insights have led to the development of vascular endothelial growth factor (VEGF) inhibitors, Mechanistic target of rapamycin (mTOR) inhibitors, and immunotherapeutic agents, which have significantly improved the outcomes of patients with advanced RCC. HIF inhibitors will be a valuable asset in the growing therapeutic armamentarium of RCC. Various histone deacetylase (HDAC) inhibitors, selenium, and agents like PT2385 and PT2977 are being explored in various clinical trials as potential HIF inhibitors, to ameliorate the outcomes of RCC patients. In this article, we will review the current treatment options and highlight the potential role of selenium in the modulation of drug resistance biomarkers expressed in clear cell RCC (ccRCC) tumors.

Selenium targets resistance biomarkers enhancing efficacy while reducing toxicity of anti-cancer drugs: preclinical and clinical development.

Selenium (Se)-containing molecules exert antioxidant properties and modulate targets associated with tumor growth, metastasis, angiogenesis, and drug resistance. Prevention clinical trials with low-dose supplementation of different types of Se molecules have yielded conflicting results. Utilizing several xenograft models, we earlier reported that the enhanced antitumor activity of various chemotherapeutic agents by selenomethione and Se-methylselenocysteine in several human tumor xenografts is highly dose- and schedule-dependent. Further, Se pretreament offered selective protection of normal tissues from drug-induced toxicity, thereby allowing higher dosing than maximum tolerated doses. These enhanced therapeutic effects were associated with inhibition of hypoxia-inducible factor 1- and 2-alpha (HIF1α, HIF2α) protein, nuclear factor (erythyroid-derived 2)-like 2 (Nrf2) and pair-related homeobox-1 (Prx1) transcription factors, downregulation of oncogenic- and upregulation of tumor suppressor miRNAs. This review provides: 1) a brief update of clinical prevention trials with Se; 2) advances in the use of specific types, doses, and schedules of Se that selectively modulate antitumor activity and toxicity of anti-cancer drugs; 3) identification of targets selectively modulated by Se; 4) plasma and tumor tissue Se levels achieved after oral administration of Se in xenograft models and cancer patients; 5) development of a phase 1 clinical trial with escalating doses of orally administered selenomethionine in sequential combination with axitinib to patients with advanced clear cell renal cell carcinoma; and 6) clinical prospects for future therapeutic use of Se in combination with anticancer drugs.

Ipilimumab: from preclinical development to future clinical perspectives in melanoma.

The arsenal for the treatment of metastatic melanoma is limited. A new approach to therapy using checkpoint blockade has improved overall survival in this patient population. Ipilimumab a CTLA-4 monoclonal antibody is a first in class drug that has pioneered this revolution. In this review, the authors provide an account of the different stages that led to the development of ipilimumab, its approval in the clinical setting for the treatment of advanced melanoma and ongoing investigations of combinatorial immune therapy.

The effect of various vitamin D supplementation regimens in breast cancer patients.

Vitamin D deficiency in the patients treated for breast cancer is associated with numerous adverse effects (bone loss, arthralgia, and falls). The first aim of this study was to assess vitamin D status, determined by 25-OH vitamin D levels, among women diagnosed with breast cancer according to demographic/clinical variables and bone mineral density (BMD). The second aim of this study was to evaluate the effect of daily low-dose and weekly high-dose vitamin D supplementation on 25-OH vitamin D levels. This retrospective study included 224 women diagnosed with stage 0-III breast cancer who received treatment at the James P. Wilmot Cancer Center at the University of Rochester Medical Center. Total 25-OH vitamin D levels (D(2) + D(3)) were determined at baseline for all participants. Vitamin D deficiency was defined as a 25-OH vitamin D level < 20 ng/ml, insufficiency as 20-31 ng/ml, and sufficiency as ≥32 ng/ml. BMD was assessed during the period between 3 months before and 6 months following the baseline vitamin D assessment. Based on the participants' baseline levels, they received either no supplementation, low-dose supplementation (1,000 IU/day), or high-dose supplementation (≥50,000 IU/week), and 25-OH vitamin D was reassessed in the following 8-16 weeks. Approximately 66.5% had deficient/insufficient vitamin D levels at baseline. Deficiency/insufficiency was more common among non-Caucasians, women with later-stage disease, and those who had previously received radiation therapy (P < 0.05). Breast cancer patients with deficient/insufficient 25-OH vitamin D levels had significantly lower lumbar BMD (P = 0.03). Compared to the no-supplementation group, weekly high-dose supplementation significantly increased 25-OH vitamin D levels, while daily low-dose supplementation did not significantly increase levels. Vitamin D deficiency and insufficiency were common among women with breast cancer and associated with reduced BMD in the spine. Clinicians should carefully consider vitamin D supplementation regimens when treating vitamin D deficiency/insufficiency in breast cancer patients.