Synergistic interaction of the histone deacetylase inhibitor SAHA with the proteasome inhibitor bortezomib in mantle cell lymphoma

Objectives:  Mantle cell lymphoma (MCL) is an incurable B cell lymphoma, and novel treatment strategies are urgently needed. We evaluated the effects of combined treatment with the proteasome inhibitor bortezomib and the histone deacetylase inhibitor (HDACi) suberoylanilide hydroxamic acid (SAHA) on MCL. Bortezomib acts by targeting the proteasome, and – among other mechanisms – results in a reduced nuclear factor-kappa B (NF-κB) activity. HDACi promote histone acetylation, and also interfere with NF-κB signaling.
Methods:  Human MCL cell lines (JeKo-1, Granta-519 and Hbl-2) were exposed to bortezomib and/or SAHA. Cell viability and apoptosis were quantified by the MTT and annexin-V assay, respectively. Reactive oxygen species (ROS) were analyzed using the fluorophore H₂DCFDA. In addition, activated caspases, proteasome- and NF-κB activity were quantified.
Results:  Combined incubation with bortezomib and SAHA resulted in synergistic cytotoxic effects, as indicated by combination index values <1 using the median effect method of Chou and Talalay. The combination of both inhibitors led to a strong increase in apoptosis as compared to single agents and was accompanied by enhanced ROS generation, while each agent alone only modestly induced ROS. The free radical scavenger N -acetyl- l -cysteine blocked the ROS generation and reduced the apoptosis significantly. In addition, coexposure of bortezomib and SAHA led to increased caspase-3, -8 and -9 activity, marked reduction of proteasome activity and decrease of NF-κB activity.
Conclusions:  This is the first report giving evidence that SAHA and bortezomib synergistically induce apoptosis in MCL cells. These data build the framework for clinical trials using combined proteasome and histone deacetylase inhibition in the treatment of MCL.     

The pathogenesis of tumour hypoglycaemia: Blocks of hepatic glucose release and of adipose tissue lipolysis

Summary Earlier findings on the pathogenesis of tumour hypoglycaemia [15] were confirmed and extended in a second patient with this disease. — A block of hepatic glucose release was found to be the main cause of hypoglycaemia in both patients suffering from large tumours of non-endocrine origin. The free fatty acid level failed to increase upon hypoglycaemia. Low free fatty acid levels correlated with an increased rate of glucose assimilation and glucose oxidation. — Immunoreactive, suppressible and nonsuppressible ILA measuredin vitro andin vivo were normal. — However, the serum of patient Z.B. inhibited lipolysis of adipose tissuein vitro to a greater extent than serum of normal subjects. This difference was no longer present after dialysis of the sera and the antilipolytic activity was now found in the diffusate. — The block of hepatic glucose release may be overcome by a pharmacological dose of intravenous glucagon. The block of hepatic glucose release is of paramount importance for the development of hypoglycaemia since the pharmacological blocking of lipolysis alone does not lead to hypoglycaemia, although it may increase glucose assimilation and glucose oxidation. — An attempt is being made to characterize further the antilipolytic substance which is present in increased amounts in the serum of patients with tumour hypoglycaemia.This work was supported by grants from the Schweizerische Nationalfonds (3336) and from the U.S. Public Health Service (AM 5387).     

Primary and secondary osteoporosis. The important role of internal medicine in its differential diagnosis

Bone metabolism as an important part of internal medicine is covered by endocrinologists, rheumatologists and nephrologists. Primary osteoporosis is an inheritable metabolic bone disease, which can be strongly modified by lifestyle, ageing and underlying diseases. Chronic inflammatory diseases, disorders of metabolism and nutritional deficits enhance the risk. Secondary osteoporosis is caused by endocrinological disorders and drugs such as glucocorticoids. It is the task of internists to clinically recognise and diagnose prominent individual risk factors for primary osteoporosis and underlying diseases for secondary osteoporosis. The key competence of internal medicine in metabolism, hormone-related disorders, malignant diseases and in handling complex medical treatment modalities represents an indispensable segment of an interdisciplinary network approach in patient care, research and teaching. This network includes orthopaedic surgery, paediatrics and gynaecology in addition to other specialties.     

Enzymatic Digestion of Adult Human Articular Cartilage Yields a Small Fraction of the Total Available Cells

We investigated whether different protocols for the digestion of adult human articular cartilage influence the cell yield and capacity to attach and proliferate in culture dishes. Chondrocyte yields were expressed as a percentage of the total number of cells in the tissue, determined both histologically (using the dissector method) and biochemically (measuring the DNA content of tissue digests). Human cartilage specimens ( n = 79) were digested using different protocols based on combinations of collagenase II (CGN), trypsin/EDTA, hyaluronidase, and tosyllysylchloromethane (TLCM). Yields of viable chondrocytes were the highest within a specific range of CGN concentrations and digestion times, but always < 22% of the total available cells. The combination of CGN with trypsin/EDTA or TLCM accelerated the digestion process but did not significantly increase cell yields. The percentage of viable cells that attached to culture dishes ranged 75-85% (< 19% of the total) and was reduced by TLCM. Doubling times of attached cells were comparable in all experimental groups. Our results indicate that chondrocyte yields and capacity to attach and proliferate are not highly sensitive to the specific isolation protocol used. However, typically used cartilage digestion protocols yield only a small fraction of the total available cells, possibly introducing an uncontrolled selection of certain chondrocyte subpopulations.     

Bone tissue engineering in osteoporosis

Osteoporosis is a polygenetic, environmentally modifiable disease, which precipitates into fragility fractures of vertebrae, hip and radius and also confers a high risk of fractures in accidents and trauma. Aging and the genetic molecular background of osteoporosis cause delayed healing and impair regeneration. The worldwide burden of disease is huge and steadily increasing while the average life expectancy is also on the rise. The clinical need for bone regeneration applications, systemic or in situ guided bone regeneration and bone tissue engineering, will increase and become a challenge for health care systems. Apart from in situ guided tissue regeneration classical ex vivo tissue engineering of bone has not yet reached the level of routine clinical application although a wealth of scaffolds and growth factors has been developed. Engineering of complex bone constructs in vitro requires scaffolds, growth and differentiation factors, precursor cells for angiogenesis and osteogenesis and suitable bioreactors in various combinations. The development of applications for ex vivo tissue engineering of bone faces technical challenges concerning rapid vascularization for the survival of constructs in vivo. Recent new ideas and developments in the fields of bone biology, materials science and bioreactor technology will enable us to develop standard operating procedures for ex vivo tissue engineering of bone in the near future. Once prototyped such applications will rapidly be tailored for compromised conditions like vitamin D and sex hormone deficiencies, cellular deficits and high production of regeneration inhibitors, as they are prevalent in osteoporosis and in higher age.     

Evozierte Potenziale bei visuellen Auren – auch heute noch der Schlüssel zur Diagnose

Clinical Epileptology - Wir berichten über einen jungen Patienten mit einer seltenen Form einer progressiven Myoklonusepilepsie. Der langwierige Weg zur richtigen Diagnose, der unterem anderem...     

Osteosarcoma of the hands and feet: a distinct clinico-pathological subgroup

Osteosarcomas of hands or feet are rare, and seemingly these cases differ in presentation and behavior compared to those in usual locations. The clinico-pathological presentation of patients with osteosarcomas of the hand or foot was studied and compared with published cases. Forty osteosarcomas were identified among 4,221 cases, representing 0.95 % of all osteosarcomas. Thirty of these were well documented. Mean age at diagnosis was 43 years (hands) and 36 years (feet) and male–female ratio was 1.2:1 and 2.0:1, respectively. In the hand, 62 % of the osteosarcomas presented in the metacarpals and 23 % in the phalanges, and only two cases occurred in the carpal bones. Distribution in the foot was tarsal bones 56 %, metatarsal bones 33 %, and phalanges 11 %.Of the cases in the hand 54 % were of high grade and of those in the foot 71 %. Survival of osteosarcomas of the hand or foot was 81 %. Only patients with high-grade osteosarcoma died of the disease. Histological grade was the only significant variable related to survival. High-grade osteosarcoma of the hand or feet should be treated similar to those in conventional sites. Osteosarcomas of hands or feet are rare and in a relative high proportion are of low grade. Survival in high-grade cases is comparable to that in conventional sites.