Investigation of autophagy as a survival factor for chronic myeloid leukaemia

Tyrosine kinase inhibitors (TKIs) have revolutionised the treatment of chronic myeloid leukemia (CML), however, fail to cure the disease due to the persistence of a refractory fraction of stem/progenitor cells. Autophagy is a recycling mechanism utilised by the cell as a survival mechanism under stressful conditions, and its induction has been suggested to have a cytoprotective role in cancer cells. In this study we demonstrate that autophagy is triggered in CML upon TKI-mediated inhibition of BCR-ABL, and protects from cell death. In order to evaluate if specific autophagy inhibition enhances TKI effects, we stably transduced primary CML stem/progenitor cells with a vector carrying a short-hairpin against the key autophagy gene ATG7. Knock-down of basal ATG7/autophagy levels in CML stem/progenitor cells inhibited by approximately 50% the survival of the cells in a clonogenic assay, and reduced by 75% their erythroid differentiation potential. Furthermore, ATG7 knock-down enhanced the effects of TKIs imatinib (IM; 1st), dasatinib (DAS; 2nd), nilotinib (NIL; 2nd) and ponatinib (PON; 3rd generation), reducing by 92-98% the survival of these cells in a clonogenic assay. In contrast, ATG7 knock-down in normal stem cells, with or without TKI treatment, did not have a significant effect on survival and proliferation. ATG7 was also knocked-down in final disease stage, blast crisis (BC), patient-derived K562 and KCL22 cell lines. Both cell lines appeared to depend significantly on autophagy for survival as indicated by high apoptosis levels (70-100%) after ATG7 knock-down. Interestingly, ATG7 knock-down cells appeared to be more differentiated compared to the control (scrambled shRNA). Our findings suggest a role for basal autophagy in the survival, differentiation decisions and clonogenicity of CML cells, and support the combined use of autophagy inhibition with TKIs for the eradication of CML stem/progenitor cells. This could be partially attributed to a bypass of the differentiation block upon autophagy inhibition, which facilitates TKI-targeting. We underline the necessity for the development of specific autophagy inhibitors that in combination with TKIs could potentially eradicate the fraction of persistent CML stem/progenitor cells and offer a curative option for CML patients

Hydroxychloroquine for chronic myeloid leukemia: complete cure on the horizon?

No abstract available

ATG7 regulates energy metabolism, differentiation and survival of Philadelphia chromosome-positive cells

A major drawback of tyrosine kinase inhibitor (TKI) treatment in chronic myeloid leukemia (CML) is that primitive CML cells are able to survive TKI-mediated BCR-ABL inhibition, leading to disease persistence in patients. Investigation of strategies aiming to inhibit alternative survival pathways in CML is therefore critical. We have previously shown that a nonspecific pharmacological inhibition of autophagy potentiates TKI-induced death in Philadelphia chromosome-positive cells. Here we provide further understanding of how specific and pharmacological autophagy inhibition affects nonmitochondrial and mitochondrial energy metabolism and reactive oxygen species (ROS)-mediated differentiation of CML cells and highlight ATG7 (a critical component of the LC3 conjugation system) as a potential specific therapeutic target. By combining extra- and intracellular steady state metabolite measurements by liquid chromatography-mass spectrometry with metabolic flux assays using labeled glucose and functional assays, we demonstrate that knockdown of ATG7 results in decreased glycolysis and increased flux of labeled carbons through the mitochondrial tricarboxylic acid cycle. This leads to increased oxidative phosphorylation and mitochondrial ROS accumulation. Furthermore, following ROS accumulation, CML cells, including primary CML CD34+ progenitor cells, differentiate toward the erythroid lineage. Finally, ATG7 knockdown sensitizes CML progenitor cells to TKI-induced death, without affecting survival of normal cells, suggesting that specific inhibitors of ATG7 in combination with TKI would provide a novel therapeutic approach for CML patients exhibiting persistent disease

Kill one bird with two stones: potential efficacy of BCR-ABL and autophagy inhibition in CML

The introduction of imatinib in the treatment of chronic myeloid leukaemia (CML) represents the most successful example of targeted therapy in human cancer. However, leukaemic stem cells (LSCs) are insensitive to tyrosine kinase inhibitors (TKIs) and contribute to disease persistence by representing a reservoir of self-renewing cells that replenish the disease upon drug discontinuation. This has re-focused the interest of scientists towards drug combinations i.e. treating with TKIs and simultaneously targeting alternative survival mechanisms. One candidate target mechanism is autophagy, a cellular recycling process that acts as a cytoprotective shield in CML cells in response to TKI-induced stress and in other cancer cells surviving in an inhospitable microenvironment. On that basis, inhibition of autophagy has now become an exciting option for combination treatment in cancer and clinical trials have been initiated in solid and haemopoietic tumours such as CML, chronic lymphocytic leukaemia (CLL) and multiple myeloma. This review describes the biology of CML and elucidates how the molecular driver BCR-ABL led to the development of TKIs. We then discuss the molecular regulation of autophagy and the potential for autophagy inhibition as the next step in our attempt to tackle the problem of CML persistence to offer a curative option

Mechanisms and novel approaches in overriding tyrosine kinase inhibitor resistance in chronic myeloid leukemia

Chronic myeloid leukemia is a stem cell-initiated but progenitor-driven disease induced by the BCR–ABL oncogene. Tyrosine kinase inhibitors (TKIs) were introduced in the late 1990s and have revolutionized the management of chronic myeloid leukemia in chronic phase. The majority of patients can now expect to live a normal life as long as they continue to comply with TKI treatment. However, in a significant proportion of cases TKI resistance develops over time, requiring a switch of therapy. The most frequent mechanism for drug resistance is the development of kinase domain mutations that reduce or completely ablate drug efficacy. Fortunately, the last 10 years have seen an impressive array of new drugs, some modeled on the mechanism of action of imatinib, others employing more novel approaches, for these patients

EUS – Fine- Needle Aspiration Biopsy (FNAB) in the Diagnosis of Pancreatic Adenocarcinoma: A Review

Solid masses of the pancreas represent a variety of benign and malignant neoplasms of the exocrine and endocrine tissues of the pancreas. A tissue diagnosis is often required to direct therapy in the face of uncertain diagnosis or if the patient is not a surgical candidate either due to advanced disease or comorbidities. Endoscopic ultrasound (EUS) is a relatively new technology that employs endoscopy and high-frequency ultrasound (US). EUS involves imaging of the pancreatic head and the uncinate from the duodenum and imaging of the body and tail from the stomach. It has been shown to be a highly sensitive method for the detection of pancreatic masses. It is superior to extracorporeal US and computed tomographic (CT) scans, especially when the pancreatic tumor is smaller than 2-3 cm. Although EUS is highly sensitive in detecting pancreatic solid masses, its ability to differentiate between inflammatory masses and malignant disease is limited. Endoscopic retrograde cholangiopancreatography (ERCP) brushing, CT-guided biopsies, and transabdominal ultrasound (US) have been the standard nonsurgical methods for obtaining a tissue diagnosis of pancreatic lesions, but a substantial false-negative rate has been reported. Transabdominal US-guided fine-needle aspiration biopsy (US-FNAB) has been used for tissue diagnosis in patients with suspected pancreatic carcinoma. It has been shown to be highly specific, with no false-positive diagnoses. With the advent of curvilinear echoendoscopes, transgastric and transduodenal EUS-FNAB of the pancreas have become a reality EUS with FNAB has revolutionized the ability to diagnose and stage cancers of the gastrointestinal tract and assess the pancreas. Gastrointestinal cancers can be looked at with EUS and their depth of penetration into the intestinal wall can be determined. Any suspicious appearing lymph nodes can be biopsied using EUS/FNAB. The pancreas is another organ that is well visualized with EUS. Abnormalities such as tumors and cysts of the pancreas can be carefully evaluated using EUS and then biopsied with FNAB. There are many new applications of EUS using FNAB. Researchers are looking to deliver chemotherapeutics into small pancreatic cancers and cysts. Nerve blocks using EUS/FNAB to inject numbing medicines into the celiac ganglia, a major nerve cluster, are now routinely performed in patients with pain due to pancreatic cancer. The aim of this study is to perform a review of the literature regarding the usefulness of EUS/FNAB in the diagnosis of pancreatic adenocarcinoma

Cytology of Pericardial Effusion due to Malignancy

Background. Malignant pericardial effusion occurs in one tenth of all cancers. It is a very serious disorder that is mainly a secondary process due to metastasis because primary neoplasms of the pericardium such as mesotheliomas, sarcomas being exceedingly rare

Assessment of the impact of a personalised nutrition intervention in impaired glucose regulation over 26 weeks: a randomised controlled trial

International audienceAbstract Dietary interventions can reduce progression to type 2 diabetes mellitus (T2DM) in people with non-diabetic hyperglycaemia. In this study we aimed to determine the impact of a DNA-personalised nutrition intervention in people with non-diabetic hyperglycaemia over 26 weeks. ASPIRE-DNA was a pilot study. Participants were randomised into three arms to receive either (i) Control arm: standard care (NICE guidelines) (n = 51), (ii) Intervention arm: DNA-personalised dietary advice (n = 50), or (iii) Exploratory arm: DNA-personalised dietary advice via a self-guided app and wearable device (n = 46). The primary outcome was the difference in fasting plasma glucose (FPG) between the Control and Intervention arms after 6 weeks. 180 people were recruited, of whom 148 people were randomised, mean age of 59 years (SD = 11), 69% of whom were female. There was no significant difference in the FPG change between the Control and Intervention arms at 6 weeks (− 0.13 mmol/L (95% CI [− 0.37, 0.11]), p = 0.29), however, we found that a DNA-personalised dietary intervention led to a significant reduction of FPG at 26 weeks in the Intervention arm when compared to standard care (− 0.019 (SD = 0.008), p = 0.01), as did the Exploratory arm (− 0.021 (SD = 0.008), p = 0.006). HbA1c at 26 weeks was significantly reduced in the Intervention arm when compared to standard care (− 0.038 (SD = 0.018), p = 0.04). There was some evidence suggesting prevention of progression to T2DM across the groups that received a DNA-based intervention (p = 0.06). Personalisation of dietary advice based on DNA did not result in glucose changes within the first 6 weeks but was associated with significant reduction of FPG and HbA1c at 26 weeks when compared to standard care. The DNA-based diet was effective regardless of intervention type, though results should be interpreted with caution due to the low sample size. These findings suggest that DNA-based dietary guidance is an effective intervention compared to standard care, but there is still a minimum timeframe of adherence to the intervention before changes in clinical outcomes become apparent. Trial Registration: www.clinicaltrials.gov.uk Ref: NCT03702465

Polyphenolic composition of grape stem extracts affects antioxidant activity in endothelial and muscle cells

The aim of the present study was the assessment of the antioxidant effects of polyphenolic extracts derived from the stems of three Greek grape varieties (Moshomayro, Mavrotragano and Mandilaria) in endothelial (EA.hy926) and muscle (C2C12) cells. We also investigated the effects of the polyphenolic composition on the antioxidant effects of the grape stem extracts. For this purpose, the endothelial and muscle cells were treated with low non-cytotoxic concentrations of the extracts for 24 h in order to assess the effects of the extracts on cellular redox status using oxidative stress biomarkers. The oxidative stress markers were thiobarbituric acid reactive substances (TBARS), protein carbonyl (CARB) levels, reactive oxygen species (ROS) levels and glutathione (GSH) levels. The results revealed that treatment of the EA.hy926 cells with