Gravity is a major physical factor determining the stress and strain around cells. Both in space experiments and ground simulation, change in gravity impacts the viability and function of various types of cells as well as in vivo conditions. Cancer cells have been shown to die under microgravity. This can be exploited for better understanding of the biology and identification of novel avenues for therapeutic intervention. Here, we described the effect of microgravity simulated using Rotational Cell Culture System-High Aspect Ratio Vessel (RCCS-HARV) on the viability and morphological changes of colorectal cancer cells. We observed DLD1, HCT116 and SW620 cells die through apoptosis under simulated microgravity (SM). Gene expression analysis on DLD1 cells showed upregulation of tumor suppressors PTEN and FOXO3; leading to AKT downregulation and further induction of apoptosis, through upregulation of CDK inhibitors CDKN2B, CDKN2D. SM induced cell clumps had elevated hypoxia and mitochondrial membrane potential that led to adaptive responses like morphogenetic changes, migration and deregulated autophagy, when shifted to normal culture conditions. This can be exploited to understand the three-dimensional (3D) biology of cancer in the aspect of stress response. This study highlights the regulation of cell function and viability under microgravity through PTEN/FOXO3/AKT pathway.

Mesenchymal stem cells (MSCs) have immense potential for cell-based therapy of acute and chronic pathological conditions. MSC transplantation for cell-based therapy requires a substantial number of cells in the range of 0.5–2.5 × 106 cells/kg body weight of an individual. A prolific source of MSCs followed by in vitro propagation is therefore an absolute prerequisite for clinical applications. Umbilical cord tissue (UCT) is an abundantly available prolific source of MSC that are fetal in nature and have higher potential for ex-vivo expansion. However, the ex-vivo expansion of MSCs using a xenogeneic supplement such as fetal bovine serum (FBS) carries the risk of transmission of zoonotic infections and immunological reactions. We used platelet lysate (PL) as a xeno-free, allogeneic replacement for FBS and compared the biological and functional characteristics of MSC processed and expanded with PL and FBS by explant and enzymatic method. UCT-MSCs expanded using PL displayed typical immunophenotype, plasticity, immunomodulatory property and chromosomal stability. PL supplementation also showed 2-fold increase in MSC yield from explant culture with improved immunomodulatory activity as compared to enzymatically dissociated cultures. In conclusion, PL from expired platelets is a viable alternative to FBS for generating clinically relevant numbers of MSC from explant cultures over enzymatic method.

Physical cues are vital in determining cellular fate in cancer. In vitro 3D culture do not replicate forces present in vivo . These forces including tumor interstitial fluid pressure and matrix stiffness behave as switches in differentiation and metastasis, which are intricate features of cancer stem cells (CSCs). Gravity determines the effect of these physical factors on cell fate and functions as evident from microgravity experiments on space and ground simulations. Here, we described the role of simulation of microgravity (SMG) using rotary cell culture system (RCCS) in increasing stemness in human colorectal cancer cell HCT116. We observed distinct features of cancer stem cells including CD133/CD44 dual positive cells and migration in SMG which was not altered by autophagy induction or inhibition. 3D and SMG increased autophagy, but the flux was staggered under SMG. Increased unique giant cancer cells housing complete nuclear localization of YAP were observed in SMG. This study highlights the role of microgravity in regulating stemness in CSC and importance of physical factors in determining the same.

Diagrammatic flowchart for the synthesis of polymeric PGS and preparation of 5FU-loaded PGS nanoparticles.

The human microbiome plays a crucial role in health and disease conditions. These microbiomes constitute a structured, coordinated microbial network throughout the human body. The oral cavity harbors one of the extensively diverse bacteria in the human system. Although many studies emphasize bacteriome and its interaction with the host system, very little attention is given to candidate phyla radiation (CPR), fungal components, and its interkingdom interaction in the oral microecology even with advanced techniques. The interkingdom interactions among caries causing microbes trigger the pathogenesis of bacterial diseases and cause ecological shifts and affect the host system. Studying the complex relations among the diverse oral microbiome and its host, especially CPR phyla and fungi, would give a holistic view of the caries etiology. This review provides evidence on the interkingdom interaction that establishes a complex community that could help predict future oral and systemic diseases.