Anti-tumorigenic effects of a novel digitoxin derivative on both estrogen receptor-positive and triple-negative breast cancer cells.

While there are targeted treatments for triple positive breast cancers, lack of specific biomarkers for triple-negative breast cancers (TNBC) has hindered the development of therapies for this subset of cancers. In this study, we evaluated the anticancer properties of cardiac glycoside Digitoxin (Dtx) and its synthetic analog MonoD on breast cancer cell lines MCF-7 (estrogen receptor-positive breast cancer) and MDA-MB-468 (triple-negative breast cancer). Both cardiac glycosides, at concentrations within the therapeutic range, increased the fraction of cells in the G0/G1 phase of the cell cycle, decreased viability, and inhibited the migration of MCF-7 and MDA-MB-468 cells. Both cardiac glycosides increased production of superoxide and induced apoptosis in both cell types. Reduced protein levels of nuclear factor kappa B and IkappaB kinase-beta were found in cardiac glycoside-treated cells, indicating that the cellular effects of these compounds are mediated via nuclear factor kappa B pathway. This study demonstrates the cytotoxic potential of digitoxin, and more importantly its synthetic analog MonoD, in the treatment of triple-positive breast cancer and more importantly the aggressive triple-negative breast cancer. Collectively, this study provides a basis for the reevaluation of cardiac glycosides in the treatment of breast cancer and more importantly reveals their potential in the treatment of triple-negative breast cancers.

Transcriptome and Metabolite analysis reveal candidate genes of the cardiac glycoside biosynthetic pathway from Calotropis procera.

Calotropis procera is a medicinal plant of immense importance due to its pharmaceutical active components, especially cardiac glycosides (CG). As genomic resources for this plant are limited, the genes involved in CG biosynthetic pathway remain largely unknown till date. Our study on stage and tissue specific metabolite accumulation showed that CG's were maximally accumulated in stems of 3 month old seedlings. De novo transcriptome sequencing of same was done using high throughput Illumina HiSeq platform generating 44074 unigenes with average mean length of 1785 base pair. Around 66.6% of unigenes were annotated by using various public databases and 5324 unigenes showed significant match in the KEGG database involved in 133 different pathways of plant metabolism. Further KEGG analysis resulted in identification of 336 unigenes involved in cardenolide biosynthesis. Tissue specific expression analysis of 30 putative transcripts involved in terpenoid, steroid and cardenolide pathways showed a positive correlation between metabolite and transcript accumulation. Wound stress elevated CG levels as well the levels of the putative transcripts involved in its biosynthetic pathways. This result further validated the involvement of identified transcripts in CGs biosynthesis. The identified transcripts will lay a substantial foundation for further research on metabolic engineering and regulation of cardiac glycosides biosynthesis pathway genes.

Comprehensive transcriptome analysis reveals novel genes involved in cardiac glycoside biosynthesis and mlncRNAs associated with secondary metabolism and stress response in Digitalis purpurea.

BACKGROUND: Digitalis purpurea is an important ornamental and medicinal plant. There is considerable interest in exploring its transcriptome. RESULTS: Through high-throughput 454 sequencing and subsequent assembly, we obtained 23532 genes, of which 15626 encode conserved proteins. We determined 140 unigenes to be candidates involved in cardiac glycoside biosynthesis. It could be grouped into 30 families, of which 29 were identified for the first time in D. purpurea. We identified 2660 mRNA-like npcRNA (mlncRNA) candidates, an emerging class of regulators, using a computational mlncRNA identification pipeline and 13 microRNA-producing unigenes based on sequence conservation and hairpin structure-forming capability. Twenty five protein-coding unigenes were predicted to be targets of these microRNAs. Among the mlncRNA candidates, only 320 could be grouped into 140 families with at least two members in a family. The majority of D. purpurea mlncRNAs were species-specific and many of them showed tissue-specific expression and responded to cold and dehydration stresses. We identified 417 protein-coding genes with regions significantly homologous or complementary to 375 mlncRNAs. It includes five genes involved in secondary metabolism. A positive correlation was found in gene expression between protein-coding genes and the homologous mlncRNAs in response to cold and dehydration stresses, while the correlation was negative when protein-coding genes and mlncRNAs were complementary to each other. CONCLUSIONS: Through comprehensive transcriptome analysis, we not only identified 29 novel gene families potentially involved in the biosynthesis of cardiac glycosides but also characterized a large number of mlncRNAs. Our results suggest the importance of mlncRNAs in secondary metabolism and stress response in D. purpurea.

Salt restriction in kidney disease--a missed therapeutic opportunity?

The importance of salt restriction in the treatment of patients with renal disease has remained highly controversial. In the following we marshal the current evidence that salt plays a definite role in the genesis of hypertension and target organ damage, point to practical problems of salt restriction, and report on novel pathomechanisms of how salt affects blood pressure and causes target organ damage.

Adherence to guidelines is a predictor of outcome in chronic heart failure: the MAHLER survey.

AIMS: The impact on outcome of the implementation of European guidelines for the treatment of chronic heart failure (CHF) has not been evaluated. We investigated the consequences of adherence to care by cardiologists on the rate of CHF and cardiovascular (CV) hospitalizations and time to CV hospitalization. METHODS AND RESULTS: We constructed class adherence indicators for angiotensin-converting enzyme (ACE)-inhibitors, beta-blockers, spironolactone, diuretics, and cardiac glycosides and GAIs (GAI3 adherence to first three classes of heart failure medication, GAI5 adherence to five classes). In the study, 1410 evaluable patients (mean age 69, 69% males, New York Heart Association (NYHA) II: 64%, III: 34%, IV: 2%) were enrolled and followed up for 6 months by 150 randomly selected cardiologists/cardiology departments from six European countries (France, Germany, Italy, The Netherlands, Spain, and UK). Overall, adherence to treatment guidelines was 60 (GAI3) and 63% (GAI5) and was better for ACE-I (88%) or diuretics (82%) than for cardiac glycosides (52%), beta-blockers (58%), and spironolactone (36%). In the three tertiles of the population defined by a decreasing mean adherence score value, CHF and CV hospitalization rates were, respectively, 6.7, 9.7, and 14.7% and 11.2, 15.9, and 20.6% (P<0.002 and P<0.001, respectively). Global adherence indicator GAI3 was an independent predictor of time to CV hospitalization in a multi-variable model together with NYHA Class, history of CHF hospitalization, ischaemic aetiology, diabetes mellitus, and hypertension. CONCLUSION: We demonstrate that adherence of physicians to treatment guidelines is a strong predictor of fewer CV hospitalizations in actual practice. There is a need to develop further quality improvement programmes in this condition.