The Role of the p14ARF Tumour Suppressor in Promoting Apoptosis

The incidence of melanoma has risen dramatically during the past three decades, yet there has been little improvement in effective treatments for this intractable and aggressive disease. Melanoma tumours are notoriously resistant to apoptosis, a cell suicide program that is activated by most cancer therapies. This thesis explores the role of the melanoma susceptibility gene product p14ARF in promoting cell cycle arrest and apoptosis, in order to resolve the impact of this tumour suppressor in melanomagenesis and melanoma susceptibility. The p14ARF tumour suppressor gene is mutated in almost half of all cancers, and germline mutations in p14ARF confer a greatly increased risk of developing melanoma. The primary function of p14ARF is to relay oncogenic signals to p53, a central regulator of cellular response to stress. There is conflicting evidence regarding the role of p14ARF in promoting apoptosis. Much of the current evidence is based on murine studies, which may not translate accurately to humans due to important differences in animal physiology and the primary sequence and functions of the mouse and human ARF proteins. Furthermore, results from previous studies are often compounded by supra-physiological expression of p14ARF, and are complicated by the fact that p14ARF shares its genomic sequence with the p16INK4a tumour suppressor gene. This study demonstrates that p14ARF expression in human cancer and primary cell lines promotes rapid p53-dependent cell cycle arrest, rather than apoptosis. As p14ARF expression did not induce apoptosis, we investigated if p14ARF could modulate the sensitivity of a cell to apoptosis induced by cytotoxic agents. Using a p14ARF-inducible U2OS osteosarcoma cell line model, we examined the impact of p14ARF expression on the apoptotic response of the cell to a panel of thirteen cytotoxic agents. p14ARF expression increased apoptosis caused by a sub-set of agents, including trichostatin A, sodium butyrate, DRB, Adriamycin and UVB radiation. p14ARF-mediated chemosensitivity was p53- and caspase-dependent, and involved the loss of mitochondrial potential. While loss of mitochondrial potential was dependent on p53, it was not blocked by caspase inhibition, demonstrating that caspases play a role downstream of mitochondrial depolarisation. Inhibition of individual components of the apoptotic program showed that p14ARF-mediated chemosensitivity was not strictly dependent on the pro-apoptotic Bax or Fas proteins. We also investigated whether p14ARF could sensitise melanoma to chemotherapeutics in vivo. We investigated the expression level of p14ARF, p16INK4a and MITFm and mutation status of B-RAF, N-RAS and PTEN in melanomas from 30 patients that had undergone isolated limb infusion - a palliative therapeutic strategy that results in much higher response rates than systemic treatment. Expression of p14ARF did not predict response to the drugs actinomycin D and melphalan . Instead, high expression of p16INK4a and presence of activating N-RAS mutation were independent predictors of response to high doses of these chemotherapeutic drugs. This work suggests that p14ARF analogues may be beneficial adjuncts in cancer therapy, but are unlikely to be effective as single agents. Additionally, p14ARF mimetics will only be effective in tumours with intact p53 signalling. Melanomas frequently carry functional p53, and may be susceptible to this mode of treatment providing the apoptotic pathway downstream of p53 is intact or can be restored

Response and survival of metastatic melanoma patients treated with immune checkpoint inhibition for recurrent disease on adjuvant dendritic cell vaccination

Vaccination with autologous dendritic cells (DC) loaded ex vivo with melanoma-associated antigens is currently being tested as an adjuvant treatment modality for resected locoregional metastatic (stage III) melanoma. Based on its mechanism of action, DC vaccination might potentiate the clinical efficacy of concurrent or sequential immune checkpoint inhibition (ICI). The purpose of this study was to determine the efficacy of ICI administered following recurrent disease during, or after, adjuvant DC vaccination. To this end, we retrospectively analyzed clinical responses of 51 melanoma patients with either irresectable stage III or stage IV disease treated with first- or second-line ICI following recurrence on adjuvant DC vaccination. Patients were analyzed according to the form of ICI administered: PD-1 inhibition monotherapy (nivolumab or pembrolizumab), ipilimumab monotherapy or combined treatment with ipilimumab and nivolumab. Treatment with first- or second-line PD-1 inhibition monotherapy after recurrence on adjuvant DC vaccination resulted in a response rate of 52%. In patients treated with ipilimumab monotherapy and ipilimumab-nivolumab response rates were 35% and 75%, respectively. In conclusion, ICI is effective in melanoma patients with recurrent disease on adjuvant DC vaccination

Dutch Oncology COVID-19 consortium:Outcome of COVID-19 in patients with cancer in a nationwide cohort study

Aim of the study: Patients with cancer might have an increased risk for severe outcome of coronavirus disease 2019 (COVID-19). To identify risk factors associated with a worse outcome of COVID-19, a nationwide registry was developed for patients with cancer and COVID-19. Methods: This observational cohort study has been designed as a quality of care registry and is executed by the Dutch Oncology COVID-19 Consortium (DOCC), a nationwide collaboration of oncology physicians in the Netherlands. A questionnaire has been developed to collect pseudonymised patient data on patients' characteristics, cancer diagnosis and treatment. All patients with COVID-19 and a cancer diagnosis or treatment in the past 5 years are eligible. Results: Between March 27th and May 4th, 442 patients were registered. For this first analysis, 351 patients were included of whom 114 patients died. In multivariable analyses, age ≥65 years (p < 0.001), male gender (p = 0.035), prior or other malignancy (p = 0.045) and active diagnosis of haematological malignancy (p = 0.046) or lung cancer (p = 0.003) were independent risk factors for a fatal outcome of COVID-19. In a subgroup analysis of patients with active malignancy, the risk for a fatal outcome was mainly determined by tumour type (haematological malignancy or lung cancer) and age (≥65 years). Conclusion: The findings in this registry indicate that patients with a haematological malignancy or lung cancer have an increased risk of a worse outcome of COVID-19. During the ongoing COVID-19 pandemic, these vulnerable patients should avoid exposure to severe acute respiratory syndrome coronavirus 2, whereas treatment adjustments and prioritising vaccination, when available, should also be considered

A young man with vision loss: keep your eyes open for a rare cause

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[Immunotherapy for cancer: from medical breakthrough to application in daily practice]

Item does not contain fulltextImmunotherapy induces a response against cancer by activating the immune system. Examples are therapies with checkpoint inhibitors, oncolytic viruses and chimeric antigen receptor T-cells (CAR T-cells). These therapies have, due to their rapid development, found their way to daily practice. For some patients with metastatic disease immunotherapy has led to significant long-term survival. Currently, there is a shift in the treatment with checkpoint inhibitors towards the (neo)adjuvant setting. Treatments with CAR T-cells seem particularly effective in haematological malignancies. Oncolytic viruses are used in the treatment for melanoma, but presently only on a limited scale. Only a limited number of patients benefit from immunotherapy. There remain many challenges for the future, most importantly the optimal use of treatment, recognition and treatment of side effects, determining the optimal duration of treatment and the increasing healthcare costs

Nivolumab-associated Nephrotic Syndrome in a Patient With Renal Cell Carcinoma: A Case Report

Item does not contain fulltextINTRODUCTION: Immune checkpoint inhibitors have taken an important place in the treatment of different types of malignancies. These drugs are known to have specific immune-mediated adverse events. We describe a case of severe nephrotic syndrome secondary to treatment with nivolumab in a patient with renal cell carcinoma. CASE PRESENTATION: A 62-year-old man was treated with nivolumab for papillary renal cell carcinoma type 2 for 8 weeks when he was admitted to the hospital with a severe nephrotic syndrome and acute kidney injury. Renal biopsy showed focal segmental glomerulosclerosis. Treatment with high-dose corticosteroids had insufficient effect, but the addition of mycophenolate mofetil resulted in remission of the nephrotic syndrome and recovery of renal function. Proteinuria subsequently relapsed during corticosteroid tapering. CONCLUSIONS: The time course in this patient strongly suggests that the nephrotic syndrome occurred as an adverse drug reaction to nivolumab treatment. If during nivolumab treatment renal insufficiency, hypoalbuminemia, or proteinuria develops, further analysis for a possible nephrotic syndrome is warranted for early detection and treatment of this life-threatening complication

Panitumumab monotherapy as a second-line treatment in metastasised colorectal cancer: a single centre experience.

Item does not contain fulltextAIMS: To report our clinical experience of panitumumab monotherapy as a second-line treatment for patients with metastatic colorectal cancer (mCRC). MATERIALS AND METHODS: This retrospective, descriptive study included a series of consecutive patients receiving panitumumab monotherapy (6 mg/kg 2 weekly) at a single centre in the Netherlands between June 2009 and November 2011. All patients had wild-type KRAS tumours, had progressed during first-line fluoropyrimidine-based therapy and were not candidates for, or refused, standard second-line therapy (usually irinotecan in the Netherlands). Prophylactic medication was given for epidermal growth factor receptor inhibitor-associated skin toxicities. RESULTS: Thirty-one patients were treated during this period. The most commonly administered first-line mCRC regimen was capecitabine/oxaliplatin/bevacizumab (18/31 patients; 58.1%). Patients received a mean of 7.9 (range 1-18) panitumumab cycles. The median progression-free survival was 3.4 (95% confidence interval 2.4, 4.4) months. The median overall survival estimates were 11.4 (95% confidence interval 1.2, 21.6) months from the initiation of panitumumab monotherapy. Ten patients experienced partial responses according to Response Evaluation Criteria In Solid Tumors (RECIST; objective response rate: 32.3%); disease was controlled (objective response or stable disease) in 15 patients (48.4%). Carcinoembryonic antigen (CEA) responses (two consecutive >/=10% decreases from baseline) occurred in 11/29 patients (37.9%); all of whom had >50% decreases in CEA levels. All patients with an objective response at week 12 had CEA reductions at weeks 6 and 12. The only adverse events were grade 1/2 skin toxicities (61.3%) and gastrointestinal complaints (6.5%); three other patients (9.7%) experienced both skin and gastrointestinal complaints. CONCLUSION: Panitumumab monotherapy seems to be a safe and active second-line treatment for patients with wild-type KRAS mCRC, with activity in line with that seen for irinotecan monotherapy, but with less toxicity. CEA may provide a useful early indicator of response to panitumumab.1 maart 201

Phosphorylated p-70S6K predicts tamoxifen resistance in postmenopausal breast cancer patients randomized between adjuvant tamoxifen versus no systemic treatment

Contains fulltext : 136517.pdf (publisher's version ) (Open Access)INTRODUCTION: Activation of the phosphatidylinositol-3-kinase (PI3K) and/or mitogen-activated protein kinase (MAPK) pathways results in anti-estrogen resistance in vitro, but a biomarker with clinical validity to predict intrinsic resistance has not been identified. In metastatic breast cancer patients with previous exposure to endocrine therapy, the addition of a mammalian target of rapamycine (mTOR) inhibitor has been shown to be beneficial. Whether or not patients on adjuvant endocrine treatment might benefit from these drugs is currently unclear. A biomarker that predicts intrinsic resistance could potentially be used as companion diagnostic in this setting. We tested the clinical validity of different downstream-activated proteins in the PI3K and/or MAPK pathways to predict intrinsic tamoxifen resistance in postmenopausal primary breast cancer patients. METHODS: We recollected primary tumor tissue from patients who participated in a randomized trial of adjuvant tamoxifen (1-3 years) versus observation. After constructing a tissue micro-array, cores from 563 estrogen receptor alpha positive were immunostained for p-AKT(Thr308), p-AKT(Ser473), p-mTOR, p-p706SK and p-ERK1/2. Cox proportional hazard models for recurrence free interval were used to assess hazard ratios and interactions between these markers and tamoxifen treatment efficacy. RESULTS: Interactions were identified between tamoxifen and p-AKT(Thr308), p-mTOR, p-p70S6K and p-ERK1/2. Applying a conservative level of significance, p-p70S6K remained significantly associated with tamoxifen resistance. Patients with p-p70S6K negative tumors derived significant benefit from tamoxifen (HR 0.24, P < 0.0001), while patients whose tumor did express p-p70S6K did not (HR = 1.02, P =0.95), P for interaction 0.004. In systemically untreated breast cancer patients, p-p70S6K was associated with a decreased risk for recurrence. CONCLUSIONS: Patients whose tumor expresses p-p70S6K, as a marker of downstream PI3K and/or MAPK pathway activation, have a favorable prognosis, but do not benefit from adjuvant tamoxifen. A potential benefit from inhibitors of the PI3K/Akt/mTOR pathway in these patients needs to be further explored

PIK3CA mutations, phosphatase and tensin homolog, human epidermal growth factor receptor 2, and insulin-like growth factor 1 receptor and adjuvant tamoxifen resistance in postmenopausal breast cancer patients

Contains fulltext : 136461.pdf (publisher's version ) (Open Access)INTRODUCTION: Inhibitors of the phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) pathway can overcome endocrine resistance in estrogen receptor (ER) alpha-positive breast cancer, but companion diagnostics indicating PI3K/AKT/mTOR activation and consequently endocrine resistance are lacking. PIK3CA mutations frequently occur in ERalpha-positive breast cancer and result in PI3K/AKT/mTOR activation in vitro. Nevertheless, the prognostic and treatment-predictive value of these mutations in ERalpha-positive breast cancer is contradictive. We tested the clinical validity of PIK3CA mutations and other canonic pathway drivers to predict intrinsic resistance to adjuvant tamoxifen. In addition, we tested the association between these drivers and downstream activated proteins. METHODS: Primary tumors from 563 ERalpha-positive postmenopausal patients, randomized between adjuvant tamoxifen (1 to 3 years) versus observation were recollected. PIK3CA hotspot mutations in exon 9 and exon 20 were assessed with Sequenom Mass Spectometry. Immunohistochemistry was performed for human epidermal growth factor receptor 2 (HER2), phosphatase and tensin homolog (PTEN), and insulin-like growth factor 1 receptor (IGF-1R). We tested the association between these molecular alterations and downstream activated proteins (like phospho-protein kinase B (p-AKT), phospho-mammalian target of rapamycin (p-mTOR), p-ERK1/2, and p-p70S6K). Recurrence-free interval improvement with tamoxifen versus control was assessed according to the presence or absence of canonic pathway drivers, by using Cox proportional hazard models, including a test for interaction. RESULTS: PIK3CA mutations (both exon 9 and exon 20) were associated with low tumor grade. An enrichment of PIK3CA exon 20 mutations was observed in progesterone receptor- positive tumors. PIK3CA exon 20 mutations were not associated with downstream-activated proteins. No significant interaction between PIK3CA mutations or any of the other canonic pathway drivers and tamoxifen-treatment benefit was found. CONCLUSION: PIK3CA mutations do not have clinical validity to predict intrinsic resistance to adjuvant tamoxifen and may therefore be unsuitable as companion diagnostic for PI3K/AKT/mTOR inhibitors in ERalpha- positive, postmenopausal, early breast cancer patients

[Immunotherapy for cancer: from medical breakthrough to application in daily practice]

Immunotherapy induces a response against cancer by activating the immune system. Examples are therapies with checkpoint inhibitors, oncolytic viruses and chimeric antigen receptor T-cells (CAR T-cells). These therapies have, due to their rapid development, found their way to daily practice. For some patients with metastatic disease immunotherapy has led to significant long-term survival. Currently, there is a shift in the treatment with checkpoint inhibitors towards the (neo)adjuvant setting. Treatments with CAR T-cells seem particularly effective in haematological malignancies. Oncolytic viruses are used in the treatment for melanoma, but presently only on a limited scale. Only a limited number of patients benefit from immunotherapy. There remain many challenges for the future, most importantly the optimal use of treatment, recognition and treatment of side effects, determining the optimal duration of treatment and the increasing healthcare costs