Apoptosis as a tool for therapeutic agents in haematological diseases

The role of substance P/neurokinin 1 receptor in the pathogenesis of esophageal squamous cell carcinoma through constitutively active PI3K/Akt/NF-κB signal transduction pathways

One of the most prevalent malignancies is esophageal squamous cell carcinoma (ESCC), which is associated with high morbidity and mortality. Substance P (SP), as one of the peptides released from sensory nerves, causes the enhancement of cellular excitability through the activation of the neurokinin-1 (NK1) receptor in several human tumor cells. Aprepitant, a specific, potent, and long-acting NK1 receptor antagonist, is considered as a novel agent to inhibit proliferation and induce apoptosis in malignant cells. Since the antitumor mechanism of aprepitant in ESCC is not completely understood, we conducted this study and found that aprepitant induced growth inhibition of KYSE-30 cells and arrested cells in the G2/M phase of the cell cycle. Aprepitant also caused apoptotic cell death and inhibited activation of the PI3K/Akt axis and its downstream effectors, including NF-κB in KYSE-30 cells. Besides, quantitative real-time (qRT)-PCR analysis showed a significant down-regulation of NF-κB target genes in KYSE-30 cells, indicating a probable NF-κB-dependent mechanism involved in aprepitant cytotoxicity. Thus, the present study recommends that SP/NK1R system might, therefore, be considered as an emerging and promising therapeutic strategy against ESCC.

CRISPR/Cas9-mediated Knockout of the Neuropsychiatric Risk Gene KCTD13 Causes Developmental Deficits in Human Cortical Neurons Derived from Induced Pluripotent Stem Cells

The human KCTD13 gene is located within the 16p11.2 locus and copy number variants of this locus are associated with a high risk for neuropsychiatric diseases including autism spectrum disorder and schizophrenia. Studies in zebrafish point to a role of KCTD13 in proliferation of neural precursor cells which may contribute to macrocephaly in 16p11.2 deletion carriers. KCTD13 is highly expressed in the fetal human brain and in mouse cortical neurons, but its contribution to the development and function of mammalian neurons is not completely understood. In the present study, we deleted the KCTD13 gene in human-induced pluripotent stem cells (iPSCs) using CRISPR/Cas9 nickase. Following neural differentiation of KCTD13 deficient and isogenic control iPSC lines, we detected a moderate but significant inhibition of DNA synthesis and proliferation in KCTD13 deficient human neural precursor cells. KCTD13 deficient cortical neurons derived from iPSCs showed decreased neurite formation and reduced spontaneous network activity. RNA-sequencing and pathway analysis pointed to a role for ERBB signaling in these phenotypic changes. Consistently, activating and inhibiting ERBB kinases rescued and aggravated, respectively, impaired neurite formation. In contrast to findings in non-neuronal human HeLa cells, we did not detect an accumulation of the putative KCTD13/Cullin-3 substrate RhoA, and treatment with inhibitors of RhoA signaling did not rescue decreased neurite formation in human KCTD13 knockout neurons. Taken together, our data provide insight into the role of KCTD13 in neurodevelopmental disorders, and point to ERBB signaling as a potential target for neuropsychiatric disorders associated with KCTD13 deficiency.

Curcumin induces p53-independent necrosis in H1299 cells via a mitochondria-associated pathway

Curcumin has been shown to have various therapeutic and/or adjuvant therapeutic effects on human cancers, as it inhibits cancer cell proliferation and induces apoptosis through p53-dependent molecular pathways. However, numerous cancer cell types bear a mutant p53 gene, and whether curcumin has any therapeutic effects on p53-deficient/mutant cancer cells has remained elusive. The present study sought to determine whether curcumin exerts any anti-proliferative and cytotoxic effects on the p53-deficient H1299 human lung cancer cell line via a p53-independent mechanism. An MTT assay and flow cytometric analysis indicated that curcumin significantly decreased cell proliferation and induced necrotic cell death. Western blot analysis of the cytosolic and mitochondrial fractions of H1299 cells as well as a fluorometric caspase assay indicated that curcumin-induced necrosis was mitochondria- and caspase-dependent, and resulted in cytochrome c release. Of note, this necrotic cell death was reduced following inhibition of B-cell lymphoma‑2 (Bcl-2)‑associated X protein (Bax) or Bcl‑2 homologous antagonist killer (Bak) as well as overexpression of Bcl-2. In conclusion, the present study suggested that curcumin-induced necrotic cell death was mediated via a p53-independent molecular pathway, which was associated with Bax and Bak translocation, caspase activation and cytochrome c release.

Advances in small animal mesentery models for in vivo flow cytometry, dynamic microscopy, and drug screening

Using animal mesentery with intravital optical microscopy is a well-established experimental model for studying blood and lymph microcirculation in vivo. Recent advances in cell biology and optical techniques provide the basis for extending this model for new applications, which should generate significantly improved experimental data. This review summarizes the achievements in this specific area, including in vivo label-free blood and lymph photothermal flow cytometry, super-sensitive fluorescence image cytometry, light scattering and speckle flow cytometry, microvessel dynamic microscopy, infrared (IR) angiography, and high-speed imaging of individual cells in fast flow. The capabilities of these techniques, using the rat mesentery model, were demonstrated in various studies; e.g., real-time quantitative detection of circulating and migrating individual blood and cancer cells, studies on vascular dynamics with a focus on lymphatics under normal conditions and under different interventions (e.g. lasers, drugs, nicotine), assessment of lymphatic disturbances from experimental lymphedema, monitoring cell traffic between blood and lymph systems, and high-speed imaging of cell transient deformability in flow. In particular, the obtained results demonstrated that individual cell transportation in living organisms depends on cell type (e.g., normal blood or leukemic cells), the cell’s functional state (e.g., live, apoptotic, or necrotic), and the functional status of the organism. Possible future applications, including in vivo early diagnosis and prevention of disease, monitoring immune response and apoptosis, chemo- and radio-sensitivity tests, and drug screening, are also discussed.

Drug resistance in diffuse large B-cell lymphoma

Despite significant advances in the treatment of diffuse large B-cell lymphoma (DLBCL), drug resistance remains a major cause of treatment failure. Early strategies to improve outcome were mostly empiric or relied on classical mechanisms of drug resistance and were largely unsuccessful. More recent approaches have been aided by an understanding of the molecular pharmacology of drug action and tumor biology. Microarray profiling in particular has provided important insights into the complex biology of DLBCL and has led to a molecular taxonomy based on cell of origin and pathways of lymphomagenesis. It is now recognized that drug resistance is a complex and dynamic process related to cell cycle and apoptotic pathways, cellular differentiation, and the microenvironment. Drugs that target potential pathways of drug resistance, such as nuclear factor kappaB (NFkappaB), cyclin-dependent kinases (CDKs), and BCL-2 have entered clinical trials. However, the complexity of drug resistance requires that future clinical trials incorporate molecular translational endpoints to help identify the biologic basis of treatment failure.