Leptin antagonism inhibits prostate cancer xenograft growth and progression

Hyperleptinaemia is a well-established therapeutic side effect of drugs inhibiting the androgen axis in prostate cancer (PCa), including main stay androgen deprivation therapy (ADT) and androgen targeted therapies (ATT). Given significant crossover between the adipokine hormone signalling of leptin and multiple cancer-promoting hallmark pathways, including growth, proliferation, migration, angiogenesis, metabolism and inflammation, targeting the leptin axis is therapeutically appealing, especially in advanced PCa where current therapies fail to be curative. In this study, we uncover leptin as a novel universal target in PCa and are the first to highlight increased intratumoural leptin and leptin receptor (LEPR) expression in PCa cells and patients' tumours exposed to androgen deprivation, as is observed in patients' tumours of metastatic and castrate resistant (CRPC) PCa. We also reveal the world-first preclinical evidence that demonstrates marked efficacy of targeted leptin-signalling blockade, using Allo-aca, a potent, specific, and safe LEPR peptide antagonist. Allo-aca-suppressed tumour growth and delayed progression to CRPC in mice bearing LNCaP xenografts, with reduced tumour vascularity and altered pathways of apoptosis, transcription/translation, and energetics in tumours determined as potential mechanisms underpinning anti-tumour efficacy. We highlight LEPR blockade in combination with androgen axis inhibition represents a promising new therapeutic strategy vital in advanced PCa treatment.

Targeting obesity-related dysfunction in hormonally driven cancers

Obesity is a risk factor for at least 13 different types of cancer, many of which are hormonally driven, and is associated with increased cancer incidence and morbidity. Adult obesity rates are steadily increasing and a subsequent increase in cancer burden is anticipated. Obesity-related dysfunction can contribute to cancer pathogenesis and treatment resistance through various mechanisms, including those mediated by insulin, leptin, adipokine, and aromatase signalling pathways, particularly in women. Furthermore, adiposity-related changes can influence tumour vascularity and inflammation in the tumour microenvironment, which can support tumour development and growth. Trials investigating non-pharmacological approaches to target the mechanisms driving obesity-mediated cancer pathogenesis are emerging and are necessary to better appreciate the interplay between malignancy, adiposity, diet and exercise. Diet, exercise and bariatric surgery are potential strategies to reverse the cancer-promoting effects of obesity; trials of these interventions should be conducted in a scientifically rigorous manner with dose escalation and appropriate selection of tumour phenotypes and have cancer-related clinical and mechanistic endpoints. We are only beginning to understand the mechanisms by which obesity effects cell signalling and systemic factors that contribute to oncogenesis. As the rates of obesity and cancer increase, we must promote the development of non-pharmacological lifestyle trials for the treatment and prevention of malignancy.

How does knowledge of the blood supply to an intracardiac tumour help?

Myxoma is a common benign tumour found in the heart. On reviewing literature, we found some left atrial myxomas receive blood supply from the right coronary artery. Performing a coronary angiogram in a cardiac tumour has the following uses: (1) it shows the vascularity that can be ligated by the surgeon at operation; (2) if there is a blood supply visible, it may not be an intracardiac thrombus; (3) the coronary angiogram may detect a myxoma even before an echocardiogram does so; (4) some myxomas may bleed into the right atrium or left atrium and this may be seen on coronary angiography. We show here the neovascularity of a left atrial myxoma and its blood supply from the right coronary artery. We recommend that all routine coronary angiograms be reviewed carefully for any signs of tumour vascularity or tumour blush as this would prevent missing early myxomas. Echocardiography is the gold standard for detection of myxomas but literature has a number of intracardiac tumours that were detected only by the tumour blush. Some left atrial tumours have been treated by occluding their blood supply.The absence of a blood supply on coronary angiography could rule out a benign cardiac tumour that usually has a blood supply.

Quantifying tumour vascularity in non-luminal breast cancers

AimsMicrovessel density (MVD), proliferating MVD (pMVD) and vascular proliferation index (VPI) are methods used to quantify tumour vascularity in histopathological sections. In this study, we assessed MVD, pMVD and VPI in non-luminal subtypes of breast cancer. Differences between subtypes were studied, and the prognostic value of each method was assessed.MethodsAll non-luminal subtypes (61 basal phenotype (BP), 60 human epidermal growth factor receptor 2 (HER2) type and 30 five negative phenotype (5NP)) were selected from a series comprising 909 cases of breast cancer. Sections were stained for Ki67 and von Willebrand factor. Associations between MVD, pMVD and VPI, molecular subtypes and prognosis were studied.ResultsMVD was highest in 5NP (Δ54.3 microvessels/mm2compared with BP, 95% CI 30.3 to 78.3), whereas no clear difference was found between HER2 type and BP (Δ8.8 microvessels/mm2, 95% CI −9.6 to 27.1). pMVD and VPI did not differ between subtypes. For MVD, HR was 1.07 (95% CI 1.03 to 1.11) per 10 vessel increase and 1.9 (95% CI 1.2 to 3.1) if MVD was greater than median value. High MVD was associated with poor prognosis in the HER2 type (HR 1.07 (95% CI 1.02 to 1.12)) and 5NP (HR 1.13 (95% CI 1.03 to 1.23)), but not in BP (HR 1.04 (95% CI 0.94 to 1.14) per 10 vessel increase). pMVD and VPI were not associated with prognosis.ConclusionsMVD appears to be an independent prognostic factor in HER2 and 5NP subtypes of breast cancer, where high MVD is associated with poor survival. MVD was higher in the 5NP compared with both BP and HER2 type.

Correlation between expressions of hypoxia -inducible factor (HIF-1α), blood vessels density, cell proliferation, and apoptosis intensity in canine fibromas and fibrosarcomas

The study aimed to demonstrate the expression of hypoxia-inducible factor (HIF-1α) in soft tissue mesenchymal tumours (fibroma and fibrosarcoma) in dogs. An attempt was made to correlate the obtained results with density of blood vessels (expression of von Willebrand Factor, vWF), expression of Ki-67 proliferation antigen, and with intensity of apoptosis in studied tumours. The study was performed on paraffin sections of 15 fibromas and 40 fibrosarcomas sampled from 55 female dogs aged 6 to 16 years. Immunohistochemical staining against HIF-1α, vWF, and Ki-67 was performed. Apoptosis was detected with the use of TUNEL reaction. A significantly higher HIF-1α expression was noted in fibrosarcomas in comparison to fibromas (P < 0.0001). HIF-1α expression in fibromas manifested strong positive correlation with tumour vascularity (r = 0.67, P = 0.007). Moreover, HIF-1α expression in fibrosarcomas manifested a moderate positive correlation with tumour malignancy grade (r = 0.44, P = 0.004), tumour vascularity (r = 0.52, P < 0.001), Ki-67 antigen expression (r = 0.42; P = 0.007), and TUNELpositive cells (r = 0.37, P = 0.017). Expression of HIF-1α was detected in 86.7% of fibroma type tumours and in 100% of fibrosarcomas. In all studied tumours expression of HIF-1α manifested positive correlation with the density of blood vessels, and in fibrosarcomas it correlated also with malignancy grade, intensity of Ki-67 expression, and with intensity of apoptosis in tumour cells.