Cyclin D1 and cyclin D3 show divergent responses to distinct mitogenic stimulation

SGLT2 inhibition restrains thyroid cancer growth via G1/S phase transition arrest and apoptosis mediated by DNA damage response signaling pathways

BACKGROUND

Although the prognosis for most patients with papillary thyroid cancer (PTC) is good, the present treatment is ineffective for 5-10% patients. Several studies found sodium-glucose cotransporter 2 (SGLT2) inhibitors may inhibit the growth of tumors. However, whether SGLT2 inhibitors have therapeutic effect on thyroid cancer remains unclear.

MATERIALS AND METHODS

The levels of SGLT2 in PTC and normal thyroid tissue were assessed by immunohistochemistry and clinical dataset analysis. Cell growth was detected by the CCK-8 and colony formation. Glucose uptake into thyroid cancer cell was evaluated by 2-DG uptake assay. Glycolysis were analyzed by Seahorse XF Extracellular Flux Analysis. RNA-seq were used to screen differentially expressed genes of cells treated with/without canagliflozin (a SGLT2 inhibitor). Furthermore, flow cytometry, western blot, and gene set enrichment analysis were employed to elucidate cell cycle, apoptosis and the underlying mechanism of the anticancer effect of canagliflozin. The effect of canagliflozin on thyroid cancer growth was further confirmed in vivo through xenograft formation assay.

RESULTS

SGLT2 inhibition attenuated the growth of thyroid cancer cells in vitro and in vivo. Canagliflozin inhibited glucose uptake, glycolysis and AKT/mTOR signaling activation, and increased AMPK activation in thyroid cancer cell. Furthermore, canagliflozin inhibited G1/S phase transition and cyclin D1, cyclin D3, cyclin E1, cyclin E2, and E2F1 expression levels in thyroid cancer cell. In addition, canagliflozin increased apoptosis of thyroid cancer cell. Further investigation revealed that canagliflozin could increase γ-H2AX expression levels and DNA damage response signaling ATM/CHK2 activation. In thyroid cancer patients, SGLT2 was increased in thyroid cancer and positively related to cyclin D3.

CONCLUSIONS

SGLT2 inhibition may limit glucose uptake resulting in energetic crisis, following oxidative stress mediated DNA damage and cell cycle arrest, which resulted to the increased cell apoptosis and decreased proliferation of thyroid cancer cells, suggesting a potential use for SGLT2 inhibitors as thyroid cancer therapeutics.

Clinicopathological analysis of splenic red pulp low-grade B-cell lymphoma

Primary splenic low-grade B-cell lymphoma of the red pulp comprises hairy cell leukemia (HCL) and splenic B-cell lymphoma/leukemia, unclassifiable (SPLL-U). SPLL-U is a rare disease that includes subtypes of a hairy cell leukemia-variant (HCL-v), splenic diffuse red pulp small B-cell lymphoma (SDRPL) and other types that are known as narrow sense SPLL-U (SPLL-U-NS). Notably, limited information is available regarding the BRAF mutation (V600E) and cyclin D3 expression in subtypes of SPLL-U. Therefore, we performed a pathological analysis of the BRAF mutation (V600E) and characterized pathological features of SPLL-U. We reviewed the pathological findings of 12 SPLL-U cases. The 12 cases considered included two cases of HCL-v, six cases of SPLL-U-NS and four undetermined cases. The BRAF mutation (V600E) was detected in three cases, which were all SPLL-U-NS. Cases with the BRAF mutation (V600E) have increased levels of CD103 expression and decreased cyclin D3 and cyclin D1 expression compared with cases that lacked the BRAF mutation. These findings suggest that the BRAF mutation might play a significant role in SPLL-U. Therefore, the significance of the BRAF mutation should be evaluated via genomic or transcriptional analyses of a large cohort of SPLL-U patients.

Ex Vivo Functionality of 3D Bioprinted Corneal Endothelium Engineered with Ribonuclease 5-Overexpressing Human Corneal Endothelial Cells

Human corneal endothelial cells (HCECs) are scarcely proliferative in vivo. The cultured HCECs engineered to overexpress ribonuclease (RNase) 5 (R5-HCECs) are prepared after transient transfection with RNase 5 plasmid vector. As candidate targets of R5-HCECs for enhancement of cellular proliferation and survival of R5-HCECs, programmed cell death protein 4 is inhibited, and cyclin D1 and cyclin E1 are activated. The cultured R5-HCECs and control HCECs on lyophilized amniotic membrane (AM) are deposited as a carrier by extrusion-based 3D bioprinting to prepare transplantable RNase 5 vector-transfected HCECs-laden AM graft (R5-Graft) and the control HCECs-laden AM graft (Ct-Graft), respectively. The ready-to-use R5-Graft shows clearer basolateral expression of Na⁺ -K⁺ ATPase pump and higher cell confluency than Ct-Graft. From 2 weeks after graft transplantation, both R5-Graft and Ct-Graft start restoring clarity of the rabbit corneas, and their central corneal edema are much less than those in the control group at 3 and 4 weeks. The ex vivo expression of corneal endothelial phenotypical markers is clear in R5-Grafs rather than in Ct-Grafts at 4 weeks. In conclusion, the fabricated corneal endothelium with cultured HCECs easily survives and functions as corneal endothelium in vivo. Furthermore, the use of the cultured HCECs engineered to overexpress RNase 5 (R5-HCECs) may be an option to obtain higher graft cellularity and to enhance the function of transplanted grafts.

A novel fibroblast activation inhibitor attenuates left ventricular remodeling and preserves cardiac function in heart failure

Cardiac fibroblasts are critical mediators of fibrotic remodeling in the failing heart and transform into myofibroblasts in the presence of profibrotic factors such as transforming growth factor-β. Myocardial fibrosis worsens cardiac function, accelerating the progression to decompensated heart failure (HF). We investigated the effects of a novel inhibitor (NM922; NovoMedix, San Diego, CA) of the conversion of normal fibroblasts to the myofibroblast phenotype in the setting of pressure overload-induced HF. NM922 inhibited fibroblast-to-myofibroblast transformation in vitro via a reduction of activation of the focal adhesion kinase-Akt-p70S6 kinase and STAT3/4E-binding protein 1 pathways as well as via induction of cyclooxygenase-2. NM922 preserved left ventricular ejection fraction ( P < 0.05 vs. vehicle) and significantly attenuated transverse aortic constriction-induced LV dilation and hypertrophy ( P < 0.05 compared with vehicle). NM922 significantly ( P < 0.05) inhibited fibroblast activation, as evidenced by reduced myofibroblast counts per square millimeter of tissue area. Picrosirius red staining demonstrated that NM922 reduced ( P < 0.05) interstitial fibrosis compared with mice that received vehicle. Similarly, NM922 hearts had lower mRNA levels ( P < 0.05) of collagen types I and III, lysyl oxidase, and TNF-α at 16 wk after transverse aortic constriction. Treatment with NM922 after the onset of cardiac hypertrophy and HF resulted in attenuated myocardial collagen formation and adverse remodeling with preservation of left ventricular ejection fraction. Future studies are aimed at further elucidation of the molecular and cellular mechanisms by which this novel antifibrotic agent protects the failing heart. NEW & NOTEWORTHY Our data demonstrated that a novel antifibrotic agent, NM922, blocks the activation of fibroblasts, reduces the formation of cardiac fibrosis, and preserves cardiac function in a murine model of heart failure with reduced ejection fraction.

Sorafenib combined with HER-2 targeted vaccination can promote effective T cell immunity in vivo

The tumor microenvironment (TME) is established and maintained through complex interactions between tumor cells and host stromal elements. Therefore, therapies that target multiple cellular components of the tumor may be most effective. Sorafenib, a multi-kinase inhibitor, alters signaling pathways in both tumor cells and host stromal cells. Thus, we explored the potential immune-modulating effects of sorafenib in a murine HER-2-(neu) overexpressing breast tumor model alone and in combination with a HER-2 targeted granulocyte-macrophage colony-stimulating factor (GM-CSF)-secreting vaccine (3T3neuGM). In vitro, sorafenib inhibited the growth of HER-2 overexpressing NT2.5 tumor cells, inducing apoptosis. Sorafenib also interfered with ERK MAPK, p38 MAPK, and STAT3 signaling, as well as cyclin D expression, but did not affect HER-2 or AKT signaling. In vivo, single agent sorafenib disrupted the tumor-associated vasculature and induced tumor cell apoptosis, effectively inducing the regression of established NT2.5 tumors in immune competent FVB/N mice. Immune depletion studies demonstrated that both CD4⁺ and CD8⁺ T cells were required for tumor regression. Sorafenib treatment did not impact the rate of tumor clearance induced by vaccination with 3T3neuGM in tumor-bearing FVB/N mice relative to either sorafenib treatment or vaccination alone. In vivo studies further demonstrated that sorafenib enhanced the accumulation of both CD4⁺ and CD8⁺ T cells into the TME of vaccinated mice. Together, these findings suggest that GM-CSF-secreting cellular immunotherapy may be integrated with sorafenib without impairing vaccine-based immune responses.

Role of D-type cyclins in heart development and disease

A defining feature of embryonic cardiomyocytes is their relatively high rates of proliferation. A gradual reduction in proliferative capacity throughout development culminates in permanent cell cycle exit by the vast majority of cardiomyocytes around the perinatal period. Accordingly, the adult heart has severely limited capacity for regeneration in response to injury or disease. The D-type cyclins (cyclin D1, D2, and D3) along with their catalytically active partners, the cyclin dependent kinases, are positive cell cycle regulators that play important roles in regulating proliferation of cardiomyocytes during normal heart development. While expression of D-type cyclins is generally low in the adult heart, expression levels are augmented in association with cardiac hypertrophy, but are uncoupled from myocyte cell division. Accordingly, re-activation of D-type cyclin expression in the adult heart has been implicated in pathophysiological processes via mechanisms distinct from those that drive proliferation during cardiac development. Growth factors and other exogenous agents regulate D-type cyclin production and activity in embryonic and adult cardiomyocytes. Understanding differences in the precise intracellular mediators downstream from these signalling molecules in embryonic versus adult cardiomyocytes could prove valuable for designing strategies to reactivate the cell cycle in cardiomyocytes in the setting of cardiovascular disease in the adult heart.