The combination of ADSCs and 10% PRP increases Rb protein expression on senescent human dermal fibroblasts

Background: The senescence process in human dermal fibroblasts (HDFs) is caused by cell cycle withdrawal processes, one of which is the result of the retinoblastoma (Rb) protein being in a hypo-phosphorylated state. Since adipose-derived stem cells (ADSCs) have a paracrine effect, ADSCs were utilized to improve the senescence process of HDFs. The use of non-autologous cell culture media to grow ADSCs can be legally problematic; therefore, platelet-rich plasma (PRP) can be considered as an alternative medium. PRP contains various growth factors that can be used to process the reversal of senescent HDFs. The combination of ADSCs and PRP is expected to increase the expression of Rb protein in HDFs that have undergone the senescence process. Methods: This study was performed in vitro with a randomized sample, and non-blinded pre-and post-test control group. The primary culture of senescent HDFs was transfected with a combination of ADSCs and 10% PRP. The effect on migration was observed through the scratch test, while the effect of PRP on reversal senescence was observed through Sa-β-gal analysis and the expression of protein Rb with ELISA. Results: The senescent HDFs that received a combined transfection of ADSCs and 10% PRP proliferated rapidly in the scratch test. Based on the Sa-β-gal assay, they showed fewer senescent HDFs cells. The combination of ADSCs and 10% PRP elevated the expression of Rb protein significantly (P < 0.001). Conclusions: The combination of ADSCs and 10% PRP was shown to have a reversal effect on the senescence process of HDFs in vitro.

Histological background of dedifferentiated solitary fibrous tumour

AimsDedifferentiation is a histological phenomenon characterised by abrupt transition of histology to a sarcomatous component with high-grade malignant potential in solitary fibrous tumour (SFT). The authors histologically reviewed SFT cases to reveal the histological background of dedifferentiated SFTs.MethodsClinicopathological and histopathological findings of 145 SFT cases were reviewed. Immunohistochemical staining and genetic analysis were also performed.ResultsThe non-dedifferentiated components showed a cellular component in 45 of 145 (31%), high mitotic rate (≥4/10 high-powered field) in 12 of 145 (8.2%) tumours, necrosis in 7 of 145 (4.8%) tumours, multinodular growth pattern in 39 of 132 (29.5%) available tumours and intratumoural fibrous septa in 37 of 131 (28.2%). Immunohistochemically, the non-dedifferentiated components were positive for CD34 in 128 of 141 (90.7%), bcl-2 in 101 of 133 (75.9%), nuclear pattern of β-catenin in 64 of 127 (50.3%) and p16 in 22 of 140 (15.7%). Loss of Rb protein expression was detected in 17 of 110 (15.4%) cases. Statistically, cellular component, multinodular structure, p16 overexpression and Rb protein loss were significantly associated with dedifferentiation. Moreover, cellular component and multinodular structure were significantly associated with p16 overexpression and Rb protein loss. All the non-deddifferentiated components showed wild type of p53 expression. The dedifferentiated components of all 10 dedifferentiated tumours presented positivity for p16 in 9 of 10 (90%) and mutational type of p53 in 5 of 10 (50%). Loss of Rb protein expression was detected in 6 of 10 (60%).ConclusionsThe authors propose that cellular or multinodular transformation may be associated with dedifferentiation. They also suggest that cellular and multinodular transformation may be associated with p16 overexpression and Rb downregulation.

Computational Analysis of Dynamical Fluctuations of Oncoprotein E7 (HPV 16) for the Hot Spot Residue Identification Using Elastic Network Model

Aims: To find out Potential Drug targets against HPV E7. Background: Oncoprotein E7 of Human Papilloma Virus (HPV-16), after invading human body alter host protein-protein interaction networks caused by the fluctuations of amino acid residues present in E7. E7 interacts with Rb protein of human host with variable residual fluctuations, leading towards the progression of cervical cancer. Objective: Our study was focused our computational analysis of the binding and competing interactions of the E7 protein of HPV with Rb protein. Methods: Our study is based on analysis of dynamic fluctuations of E7 in host cell and correlation analysis of specific residue found in motif of LxCxE, that is the key region in stabilizing interaction between E7 and Rb. Results and Discussion: Cysteine, Leucine and Glutamic acid have been identified as hot spot residues of E7 which can provide platform for drug designing and understanding of pathogenesis of cervical cancer, in future. Our study shows validation of the vitality of linear binding motifs LxCxE of E7 of HPV in interacting with Rb as an important event in propagation of HPV in human cells and transformation of infection into cervical cancer. Conclusion: Our study shows validation of the vitality of linear binding motifs LxCxE of E7 of HPV in interacting with Rb as an important event in propagation of HPV in human cells and transformation of infection into cervical cancer. Other: E7 interacts with Rb protein of human host with variable residual fluctuations, leading towards the progression of cervical cancer.

Systematic exploration of different E3 ubiquitin ligases: an approach towards potent and selective CDK6 degraders

Cyclin-dependent kinase 6 (CDK6) is an important regulator of the cell cycle. Together with CDK4, it phosphorylates and inactivates retinoblastoma (Rb) protein.

An RB-Condensin II Complex Mediates Long-Range Chromosome Interactions and Influences Expression at Divergently Paired Genes

ABSTRACT Interphase chromosomes are organized into topologically associated domains in order to establish and maintain integrity of transcriptional programs that remain poorly understood. Here, we show that condensin II and TFIIIC are recruited to bidirectionally transcribed promoters by a mechanism that is dependent on the retinoblastoma (RB) protein. Long-range chromosome contacts are disrupted by loss of condensin II loading, which leads to altered expression at bidirectional gene pairs. This study demonstrates that mammalian condensin II functions to organize long-range chromosome contacts and regulate transcription at specific genes. In addition, RB dependence of condensin II suggests that widespread misregulation of chromosome contacts and transcriptional alterations are a consequence of RB mutation.

Critical role for P53 in regulating the cell cycle of ground state embryonic stem cells

Mouse Embryonic Stem Cells (ESCs) grown in serum-supplemented conditions are characterized by an extremely short G1-phase due to the lack of G1-phase control. Concordantly, the G1-phase-specific P53-P21 pathway is compromised in serum ESCs. Here we provide evidence that P53 is activated upon transition of serum ESCs to their pluripotent ground state using serum-free 2i conditions and modulates G1-phase progression. Our data shows that the elongated G1-phase characteristic of ground state ESCs is dependent on P53. RNA-seq and ChIP-seq analyses reveal that P53 directly regulates the expression of the Retinoblastoma (RB) protein and that the hypo-phosphorylated, active RB protein plays a key role in G1-phase control. Our findings suggest that the P53-P21 pathway is active in ground state 2i ESCs and that its role in the G1-checkpoint is abolished in serum ESCs. Taken together, the data reveals a mechanism by which inactivation of P53 can lead to loss of RB and uncontrolled cell proliferation.

Developmental-stage-specific proliferation and retinoblastoma genesis in RB-deficient human but not mouse cone precursors

Most retinoblastomas initiate in response to the inactivation of the RB1 gene and loss of functional RB protein. The tumors may form without additional genomic changes and develop after a pre-malignant retinoma phase. Despite this seemingly straightforward etiology, mouse models have not recapitulated the genetic, cellular, and stage-specific features of human retinoblastoma genesis. For example, whereas human retinoblastomas appear to derive from cone photoreceptor precursors, current mouse models develop tumors that derive from other retinal cell types. To investigate the basis of the human cone-specific oncogenesis, we compared developmental-stage-specific cone precursor responses to RB loss in human and murine retina cultures and in cone-specific Rb1 knockout mice. We report that RB-depleted maturing (ARR3+) but not immature (ARR3-) human cone precursors enter the cell cycle, proliferate, and form retinoblastoma-like lesions characterized by Flexner-Wintersteiner rosettes, then form low or non-proliferative pre-malignant retinoma-like lesions with fleurettes and high p16INK4A and p130 expression, and finally form highly proliferative retinoblastoma-like masses. In contrast, in murine retina, only RB-depleted immature (Arr3-) cone precursors entered the cell cycle and they failed to progress from S to M phase. Moreover, whereas the intrinsically highly expressed MDM2 and MYCN contribute to RB-depleted maturing (ARR3+) human cone precursor proliferation, ectopic MDM2 and Mycn promoted only immature (Arr3-) murine cone precursor cell cycle entry. These findings demonstrate that developmental-stage-specific as well as speciesand cell-type-specific features sensitize to RB1 inactivation and reveal the human cone precursors’ capacity to model retinoblastoma initiation, proliferation, pre-malignant arrest, and tumor growth.Significance StatementRetinoblastoma is a childhood tumor that forms in response to mutations in the RB1 gene and loss of functional RB protein. Prior studies suggested that retinoblastomas arise from cone photoreceptor precursors, whereas mouse models yield tumors deriving from other retinal cell types and lacking human retinoblastoma features. Here, we show that in cultured human retinae, retinoblastomas initiate from RB-depleted cone precursors that are in a specific maturation state and form pre-malignant “retinomas” prior to retinoblastoma lesions, as is believed to occur in retinoblastoma patients. In contrast, Rb-deficient mouse cone precursors of similar maturation state and supplemented with human-cone-precursor-specific oncoproteins fail to proliferate. Thus, human species-specific developmental features underlie retinoblastomagenesis and may challenge the production of accurate mouse retinoblastoma models.