Mitogenic Effect Research Articles

Phosphatidic Acid Stimulates Myoblast Proliferation through Interaction with LPA1 and LPA2 Receptors.

Phosphatidic acid (PA) is a bioactive phospholipid capable of regulating key biological functions, including neutrophil respiratory burst, chemotaxis, or cell growth and differentiation. However, the mechanisms whereby PA exerts these actions are not completely understood. In this work, we show that PA stimulates myoblast proliferation, as determined by measuring the incorporation of [3H]thymidine into DNA and by staining the cells with crystal violet. PA induced the rapid phosphorylation of Akt and ERK1/2, and pretreatment of the cells with specific small interferin RNA (siRNA) to silence the genes encoding these kinases, or with selective pharmacologic inhibitors, blocked PA-stimulated myoblast proliferation. The mitogenic effects of PA were abolished by the preincubation of the myoblasts with pertussis toxin, a Gi protein inhibitor, suggesting the implication of Gi protein-coupled receptors in this action. Although some of the effects of PA have been associated with its possible conversion to lysoPA (LPA), treatment of the myoblasts with PA for up to 60 min did not produce any significant amount of LPA in these cells. Of interest, pharmacological blockade of the LPA receptors 1 and 2, or specific siRNA to silence the genes encoding these receptors, abolished PA-stimulated myoblast proliferation. Moreover, PA was able to compete with LPA for binding to LPA receptors, suggesting that PA can act as a ligand of LPA receptors. It can be concluded that PA stimulates myoblast proliferation through interaction with LPA1 and LPA2 receptors and the subsequent activation of the PI3K/Akt and MEK/ERK1-2 pathways, independently of LPA formation.

Resistin-like molecule \u03b2 acts as a mitogenic factor in hypoxic pulmonary hypertension via the Ca2+-dependent PI3K/Akt/mTOR and PKC/MAPK signaling pathways

BackgroundPulmonary arterial smooth muscle cell (PASMC) proliferation plays a crucial role in hypoxia-induced pulmonary hypertension (HPH). Previous studies have found that resistin-like molecule β (RELM-β) is upregulated de novo in response to hypoxia in cultured human PASMCs (hPASMCs). RELM-β has been reported to promote hPASMC proliferation and is involved in pulmonary vascular remodeling in patients with PAH. However, the expression pattern, effects, and mechanisms of action of RELM-β in HPH remain unclear.MethodsWe assessed the expression pattern, mitogenetic effect, and mechanism of action of RELM-β in a rat HPH model and in hPASMCs.ResultsOverexpression of RELM-β caused hemodynamic changes in a rat model of HPH similar to those induced by chronic hypoxia, including increased mean right ventricular systolic pressure (mRVSP), right ventricular hypertrophy index (RVHI) and thickening of small pulmonary arterioles. Knockdown of RELM-β partially blocked the increases in mRVSP, RVHI, and vascular remodeling induced by hypoxia. The phosphorylation levels of the PI3K, Akt, mTOR, PKC, and MAPK proteins were significantly up- or downregulated by RELM-β gene overexpression or silencing, respectively. Recombinant RELM-β protein increased the intracellular Ca2+ concentration in primary cultured hPASMCs and promoted hPASMC proliferation. The mitogenic effects of RELM-β on hPASMCs and the phosphorylation of PI3K, Akt, mTOR, PKC, and MAPK were suppressed by a Ca2+ inhibitor.ConclusionsOur findings suggest that RELM-β acts as a cytokine-like growth factor in the development of HPH and that the effects of RELM-β are likely to be mediated by the Ca2+-dependent PI3K/Akt/mTOR and PKC/MAPK pathways.

Plausible Role of Estrogens in Pathogenesis, Progression and Therapy of Lung Cancer.

Malignant neoplasms are among the most common diseases and are responsible for the majority of deaths in the developed world. In contrast to men, available data show a clear upward trend in the incidence of lung cancer in women, making it almost as prevalent as breast cancer. Women might be more susceptible to the carcinogenic effect of tobacco smoke than men. Furthermore, available data indicate a much more frequent mutation of the tumor suppressor gene-p53 in non-small cell lung cancer (NSCLC) female patients compared to males. Another important factor, however, might lie in the female sex hormones, whose mitogenic or carcinogenic effect is well known. Epidemiologic data show a correlation between hormone replacement therapy (HRT) or oral contraceptives (OCs), and increased mortality rates due to the increased incidence of malignant tumors, including lung cancer. Interestingly, two types of estrogen receptors have been detected in lung cancer cells: ERα and ERβ. The presence of ERα has been detected in tissues and non-small-cell lung carcinoma (NSCLC) cell lines. In contrast, overexpression of ERβ is a prognostic marker in NSCLC. Herein, we summarize the current knowledge on the role of estrogens in the etiopathogenesis of lung cancer, as well as biological, hormonal and genetic sex-related differences in this neoplasm.

TBK1 regulates regeneration of pancreatic \u03b2-cells

Small-molecule inhibitors of non-canonical IκB kinases TANK-binding kinase 1 (TBK1) and IκB kinase ε (IKKε) have shown to stimulate β-cell regeneration in multiple species. Here we demonstrate that TBK1 is predominantly expressed in β-cells in mammalian islets. Proteomic and transcriptome analyses revealed that genetic silencing of TBK1 increased expression of proteins and genes essential for cell proliferation in INS-1 832/13 rat β-cells. Conversely, TBK1 overexpression decreased sensitivity of β-cells to the elevation of cyclic AMP (cAMP) levels and reduced proliferation of β-cells in a manner dependent on the activity of cAMP-hydrolyzing phosphodiesterase 3 (PDE3). While the mitogenic effect of (E)3-(3-phenylbenzo[c]isoxazol-5-yl)acrylic acid (PIAA) is derived from inhibition of TBK1, PIAA augmented glucose-stimulated insulin secretion (GSIS) and expression of β-cell differentiation and proliferation markers in human embryonic stem cell (hESC)-derived β-cells and human islets. TBK1 expression was increased in β-cells upon diabetogenic insults, including in human type 2 diabetic islets. PIAA enhanced expression of cell cycle control molecules and β-cell differentiation markers upon diabetogenic challenges, and accelerated restoration of functional β-cells in streptozotocin (STZ)-induced diabetic mice. Altogether, these data suggest the critical function of TBK1 as a β-cell autonomous replication barrier and present PIAA as a valid therapeutic strategy augmenting functional β-cells.

Old Player-New Tricks: Non Angiogenic Effects of the VEGF/VEGFR Pathway in Cancer.

Simple SummaryAlthough VEGF-A is well characterized as the principal player of cancer angiogenesis, new data on the interplay with other components of the tumor microenvironment emerge. Here we review the effect of VEGF-A on cancer cells and immune cells as well as investigative and established combinational therapies of anti-angiogenic agents with immune checkpoint inhibitors. We thus elaborate the scientific rationale behind the development of these novel combinational approaches.Angiogenesis has long been considered to facilitate and sustain cancer growth, making the introduction of anti-angiogenic agents that disrupt the vascular endothelial growth factor/receptor (VEGF/VEGFR) pathway an important milestone at the beginning of the 21st century. Originally research on VEGF signaling focused on its survival and mitogenic effects towards endothelial cells, with moderate so far success of anti-angiogenic therapy. However, VEGF can have multiple effects on additional cell types including immune and tumor cells, by directly influencing and promoting tumor cell survival, proliferation and invasion and contributing to an immunosuppressive microenvironment. In this review, we summarize the effects of the VEGF/VEGFR pathway on non-endothelial cells and the resulting implications of anti-angiogenic agents that include direct inhibition of tumor cell growth and immunostimulatory functions. Finally, we present how previously unappreciated studies on VEGF biology, that have demonstrated immunomodulatory properties and tumor regression by disrupting the VEGF/VEGFR pathway, now provide the scientific basis for new combinational treatments of immunotherapy with anti-angiogenic agents.

Tumor exposed-lymphatic endothelial cells promote primary tumor growth via IL6.

Solid tumors are composed of tumor cells and stromal cells including lymphatic endothelial cells (LEC), which are mainly viewed as cells forming lymphatic vessels involved in the transport of metastatic and immune cells. We here reveal a new mechanism by which tumor exposed-LEC (teLEC) exert mitogenic effects on tumor cells. Our conclusions are supported by morphological and molecular changes induced in teLEC that in turn enhance cancer cell invasion in 3D cultures and tumor cell proliferation in vivo. The characterization of teLEC secretome by RNA-Sequencing and cytokine array revealed that interleukine-6 (IL6) is one of the most modulated molecules in teLEC, whose production was negligible in unexposed LEC. Notably, neutralizing anti-human IL6 antibody abrogated teLEC-mediated mitogenic effects in vivo, when LEC were mixed with tumor cells in the ear sponge assay. We here assign a novel function to teLEC that is beyond their role of lymphatic vessel formation. This work highlights a new paradigm, in which teLEC exert “fibroblast-like properties”, contribute in a paracrine manner to the control of tumor cell properties and are worth considering as key stromal determinant in future studies.

The cytoskeleton actin binding protein filamin A impairs both IGF2 mitogenic effects and the efficacy of IGF1R inhibitors in adrenocortical cancer cells.

Adrenocortical carcinomas (ACCs) overexpress insulin-like growth factor 2 (IGF2), that drives a proliferative autocrine loop by binding to IGF1R and IR, but IGF1R/IR-targeted therapies failed in ACC patients. The cytoskeleton actin-binding protein filamin A (FLNA) impairs IR signalling in melanoma cells. Aims of this study were to test FLNA involvement in regulating IGF1R and IR responsiveness to both IGF2 and inhibitors in ACC. In ACC cells H295R and SW13 and primary cultures (1ACC, 4 adenomas) we found that IGF1R and IR interacted with FLNA, and FLNA silencing increased IGF1R and reduced IR expression, with a downstream effect of increased cell proliferation and ERK phosphorylation. In addition, FLNA knockdown potentiated antiproliferative effects of IGF1R/IR inhibitor Linsitinib and IGF1R inhibitor NVP-ADW742 in H295R. Finally, Western blot showed lower FLNA expression in ACCs (n=10) than in ACAs (n=10) and an inverse correlation of FLNA/IGF1R ratio with ERK phosphorylation in ACCs only. In conclusion, we demonstrated that low FLNA levels enhance both IGF2 proliferative effects and IGF1R/IR inhibitors efficacy in ACC cells, suggesting FLNA as a new factor influencing tumor clinical behavior and the response to the therapy with IGF1R/IR-targeted drugs.

Tp53 Suppression Promotes Cardiomyocyte Proliferation during Zebrafish Heart Regeneration

SUMMARYZebrafish regenerate heart muscle through division of pre-existing cardiomyocytes. To discover underlying regulation, we assess transcriptome datasets for dynamic gene networks during heart regeneration and identify suppression of genes associated with the transcription factor Tp53. Cardiac damage leads to fluctuation of Tp53 protein levels, concomitant with induced expression of its central negative regulator, mdm2, in regenerating cardiomyocytes. Zebrafish lacking functional Tp53 display increased indicators of cardiomyocyte proliferation during regeneration, whereas transgenic Mdm2 blockade inhibits injury-induced cardiomyocyte proliferation. Induced myocardial overexpression of the mitogenic factors Nrg1 or Vegfaa in the absence of injury also upregulates mdm2 and suppresses Tp53 levels, and tp53 mutations augment the mitogenic effects of Nrg1. mdm2 induction is spatiotemporally associated with markers of de-differentiation in injury and growth contexts, suggesting a broad role in cardiogenesis. Our findings reveal myocardial Tp53 suppression by mitogen-induced Mdm2 as a regulatory component of innate cardiac regeneration.

Molecular characterization of Antheraea mylitta arylphorin gene and its encoded protein

Antheraea mylitta arylphorin protein was extracted from the silk gland of fifth instar larvae and purified by ammonium sulphate precipitation, ion-exchange, and gel filtration chromatography. The N-terminal sequencing of ten amino acids (NH2-SVVHPPHHEV-COOH) showed similarity with Antheraea pernyi arylphorin. Based on N-terminal and C-terminal A. pernyi arylphorin sequences, primers were designed, and A. mylitta arylphorin cDNA was cloned by RT-PCR from silk gland mRNA. Sequencing of complete cDNA including 25 nucleotides at 5′ UTR (obtained by 5′ RACE) showed that it consisted of an ORF of 2115 nucleotides which could encode a protein of 704 amino acids (predominantly aromatic residues) having molecular weight 83 kDa. Homology modelling was done using A. pernyi arylphorin as a template. Cloned arylphorin cDNA was expressed in E. coli and recombinant His-tagged protein was purified by Ni-NTA affinity chromatography. Analysis of tissue-specific expression of arylphorin by real-time PCR showed maximum expression in the fat body followed by silk gland and integument. 5’ flanking region (759 bp) of arylphorin gene was amplified by inverse PCR and the full length gene (5359 nucleotides) containing five exons and four introns was cloned from the A. mylitta genomic DNA and sequenced. Polyclonal antibody was raised against purified arylphorin and more native arylphorin protein (500 kDa) was purified from the fat body by antibody affinity chromatography. Study of mitogenic effect of native and chymotrypsin hydrolysate of arylphorin on different insect cell lines showed that arylphorin could be used as serum substitute for in vitro cultivation of insect cells.

Inhibition of Rab27a and Rab27b Has Opposite Effects on the Regulation of Hair Cycle and Hair Growth.

Rab27a/b are known to play an important role in the transport of melanosomes, with their knockout causing silvery gray hair. However, the relationship between Rab27a/b and hair growth is not well known. To evaluate the role of Rab27a/b in hair cycle, we investigated the expression of Rab27a/b during hair cycling and human outer root sheath (hORS) cells. The expression of Rab27a in ORS cells was mainly detected at the anagen, whereas expression of Rab27b in ORS, and epidermal cells was strongly expressed at the telogen. Additionally, Rab27a/b were expressed in the Golgi of hORS cells. To evaluate the role of Rab27a/b in hair growth, telogen-to-anagen transition animal and vibrissae hair follicles (HFs) organ culture models were assayed using Rab27a/b siRNAs. The knockdown of Rab27a or Rab27b suppressed or promoted hair growth, respectively. These results were also confirmed in human dermal papilla cells (hDPCs) and hORS cells, showing the opposite mitogenic effects. Moreover, Rab27b knockdown increased the expression levels of various growth factors in the hDPCs and hORS cells. Overall, the opposite temporal expression patterns during hair cycling and roles for hair growth of Rab27a/b suggested that Rab27a/b might regulate the hair cycle. Therefore, our study may provide a novel solution for the development of hair loss treatment by regulating Rab27a/b levels.

Comparison of the Hepatic Effects of Phenobarbital in Chimeric Mice Containing Either Rat or Human Hepatocytes With Humanized Constitutive Androstane Receptor and Pregnane X Receptor Mice.

Using a chimeric mouse humanized liver model, we provided evidence that human hepatocytes are refractory to the mitogenic effects of rodent constitutive androstane receptor (CAR) activators. To evaluate the functional reliability of this model, the present study examined mitogenic responses to phenobarbital (PB) in chimeric mice transplanted with rat hepatocytes, because rats are responsive to CAR activators. Treatment with 1000 ppm PB for 7 days significantly increased replicative DNA synthesis (RDS) in rat hepatocytes of the chimeric mice, demonstrating that the transplanted hepatocyte model is functionally reliable for cell proliferation analysis. Treatment of humanized CAR and pregnane X receptor (PXR) mice (hCAR/hPXR mice) with 1000 ppm PB for 7 days significantly increased hepatocyte RDS together with increases in several mitogenic genes. Global gene expression analysis was performed with liver samples from this and from previous studies focusing on PB-induced Wnt/β-catenin signaling and showed that altered genes in hCAR/hPXR mice clustered most closely with liver tumor samples from a diethylnitrosamine/PB initiation/promotion study than with wild-type mice. However, different gene clusters were observed for chimeric mice with human hepatocytes for Wnt/β-catenin signaling when compared with those of hCAR/hPXR mice, wild-type mice, and liver tumor samples. The results of this study demonstrate clear differences in the effects of PB on hepatocyte RDS and global gene expression between human hepatocytes of chimeric mice and hCAR/hPXR mice, suggesting that the chimeric mouse model is relevant to humans for studies on the hepatic effects of rodent CAR activators whereas the hCAR/hPXR mouse is not.

Evaluation of Cell Proliferation in Rat Mammary Glands Is Not Predictive of the Carcinogenic Potential of Insulin In Vivo.

For nonclinical safety-assessment of insulin analogues in vivo, mitogenic effects are compared to that of human insulin. Besides histopathologic evaluation, this usually includes assessment of cell proliferation (CP) in mammary glands. Insulin analogue X10 is recommended as positive control, due to its known carcinogenic effect in rat mammary glands. Here, we discuss the mitogenic effect of insulin in vivo and use of X10 as positive control. We present results from 4 nonclinical rat studies evaluating effects of repeated dosing with insulin detemir (≤26 weeks) or degludec (52 weeks) in mammary glands. Studies included human insulin-dosed groups as comparators, CP, and histopathologic evaluation. One study included an X10-dosed group (26 weeks), another ≤3 weeks of dosing with X10 or human insulin evaluating effects of these comparators. Neither human insulin, insulin detemir, degludec, nor X10 induced mammary tumors or increased CP in the studies. The CP marker proliferating cell nuclear antigen varied within/between studies and was not correlated with the remaining markers or CP fluctuations during estrous cycle, whereas the other CP markers, Ki-67 and 5-bromo-2'-deoxyuridine (BrdU), correlated with estrous cycle changes and each other. In conclusion, we propose that the mitogenic effect of insulin in rat mammary glands is weak in vivo. Cell proliferation evaluation in nonclinical safety assessment studies is not predictive of the carcinogenic potential of insulin, thus, the value of including this end point is debatable. Moreover, X10 is not recommended as positive control, due to lack of proliferative effects. Typical CP markers vary greatly in quality, BrdU seemingly most reliable.

Enhancement of Skin Wound Healing by rhEGF-Loaded Carboxymethyl Chitosan Nanoparticles.

The self-assembly of hydrophobically modified polymers has become a research hotspot due to its wide application in the biomedical field. Recombinant human epidermal growth factors (rhEGFs) are molecules that are able to enhance wound healing; however, they have a short half-life and require sustained action to enhance their mitogenic effect on epithelial cells. Here, we proposed a new delivery system to avoid the inhibition of rhEGF by various enzymes, thus improving its bioavailability and sustained release. The amphiphilic polymer was composed of conjugated linoleic acid (CLA) and carboxymethyl chitosan (CMCS), which were further characterized by fourier transformed infrared spectroscopy (FTIR) and 1H nuclear magnetic resonance (1H NMR). Then, the self-assembly behavior of CLA–CMCS (CC) polymer in water was observed in which the particle size of CC decreased from 196 to 155 nm with the degree of CLA substitution increasing. The nanoparticles were loaded with rhEGF and the maximum rhEGF loading efficiency (LE) of CC3 nanoparticles was 82.43 ± 3.14%. Furthermore, CC nanoparticles (NPs) exhibited no cytotoxicity for L929 cells, and cell proliferation activity was well preserved after rhEGF loading to CC-NPs and was comparable to that of free rhEGF. Topically applied rhEGF:CC-NPs significantly accelerated the wound-closure rate in full thickness, which was most probably due to its sustained release and enhanced skin permeation. In conclusion, carboxymethyl chitosan-based nanoparticles were constructed and showed good cytocompatibility. Moreover, these findings also demonstrated the therapeutic potential of rhEGF:CC-NPs as a topical wound-healing drug carrier.

Abstract IA20: Neuronal activity promotes proliferation of normal and neoplastic glial cells

Abstract Neuronal activity regulates the proliferation and differentiation of oligodendrocyte precursor cells during development and in adulthood. In the healthy brain, this results in activity-regulated plasticity of myelination and subsequent modulation of neural circuit function evident in oligodendrogenesis-dependent behavioral changes. The robust mitogenic effect of neuronal activity on normal neural precursor and oligodendroglial precursor cells, a putative cellular origin of pediatric high-grade gliomas (HGG), suggests that dysregulated or “hijacked” mechanisms of myelin plasticity might similarly promote proliferation in this devastating group of childhood brain cancers. Using in vivo and in situ optogenetic techniques together with patient-derived high-grade glioma cell cultures and xenograft models, we have demonstrated that neuronal activity similarly promotes proliferation and growth of both pediatric and adult high-grade glioma subtypes. Crucial mechanisms mediating activity-regulated high-grade glioma growth include secretion of Brain Derived Neurotrophic Factor (BDNF) and the synaptic protein neuroligin-3 (NLGN3), which induces multiple oncogenic signaling pathways together with robust changes in synaptic gene expression in glioma cells. Nlgn3 is necessary for the growth of high-grade glioma xenografts in the mouse brain, and NLGN3 expression levels in human HGG negatively correlate with patient overall survival. Thus, neuronal activity not only modulates the structure and function of the brain’s myelinated infrastructure, but neurons also play an important role in the brain tumor microenvironment, with activity-regulated secretion of NLGN3 emerging as an unexpected and therapeutically targetable mechanism underlying axon-glioma interactions and promoting neuronal activity-regulated cancer growth.

Silk sericin as a biomaterial for tissue engineering: a review

Silk sericin is a natural polymer produced by silkworm Bombyx mori; which has the function of covering the fibroin filaments so that they remain linked together as well as maintaining the structural integrity of the cocoon. Despite its properties and benefits, sericin is currently discarded during textile production as it is considered a side product of silk cocoons during the degumming process. Among the most important biological properties of sericin are good oxygen permeability, moisture-regulating capacity, resistance to UV radiation, ability to promotes cell growth, biocompatibility and mitogenic effect. All these characteristics make sericin a promising polymer to be used in biomedical applications, especially in tissue engineering and regenerative medicine. Some studies report that sericin favors the biological nature of keratinocytes and fibroblasts, potentializing it as a biomaterial for the repair of epithelial tissue, mainly utilized as wound dressing. Given the importance that sericin can have in the field of bioengineering, and that its use can favor the sericulture agroindustry, this manuscript reviews recent studies of this protein for its application in tissue engineering, specifically for cutaneous regeneration. Highlights Research on SS represents a promising and developing field. SS decreases cell adhesion and favors the proliferation of keratinocytes and fibroblasts. SS has been shown to have a mitogenic effect in some mammalian cells. SS can be crosslinked, copolymerized, and mixed with other polymers.

Lipodystrophy at the insulin injection sites: current trends in epidemiology, diagnostics and prevention

Lipodystrophy at the injection sites is most common local complication of insulin therapy. The history of its study started in 1926, when first cases of lipoatrophy at the sites of insulin injections were described. As we moved to human insulin and insulin analogues, immune mediated atrophic form of lipodystrophy has been replaced by hypertrophic one, which reflects anabolic and mitogenic effect of insulin.
 Lipohypertrophy at the injection sites is detected by physical examination in 40-70% of insulin-treated subjects. The detection efficiency depends on health care provider`s skills. Therefore, training of medical doctors and nurses in physical examination of injection sites seems to be reasonable.
 In recent years, ultrasound was introduced for diagnostics of insulin-induced lipohypertrophy. The method is more sensitive compared to palpation; ultrasound-verified lipohypertropthy was detected in more than 80% of cases. In patients with wide-spread lipohypertrophy ultrasound can be used to find suitable sites for injections (ultrasound injection map). Strain sonoelastography and 3D-power Doppler ultrasound can be used for quantitative estimation of rigidity and vascularization of lipohypertrophy. Both MRI and infrared images are considered as promising diagnostic tools.
 In a number of studies, it has been shown that the presence of lipohypertrophy is associated with high HbA1c levels, enhanced glycemic variability, unexplained hypoglycemia, and increased insulin doses. Thereby, lipohypertrophy aggravates the diabetes-related costs.
 The main risk factor for lipohypertrophy is inappropriate injection technique, including the lack of the site rotation, injections into lipodystrophic lesions, small injection area, reuse or excessive length of the needles. Accordingly, training patients in the injection technique is the basis for prevention of complication. The cessation of injections in lipohypertrophy areas and regular site rotation is essential for adequate titration of insulin dose and achievement of glycemic targets.

236-OR: Molecular and Biological Properties of Insulin Icodec, a New Insulin Analog Designed to Give a Long Half-Life Suitable for Once-Weekly Dosing

Insulin icodec is a novel insulin analog with a terminal elimination half-life of ∼196 hours currently in clinical development, designed to be able to cover a full week’s basal insulin requirements with a single subcutaneous injection. To attain such a long half-life, the insulin molecule was modified to achieve an albumin-bound circulating depot of icodec which acts just as human insulin (HI) but is more slowly cleared.Addition of a C20 fatty diacid containing side chain at B29K via a hydrophilic linker imparts strong but reversible albumin binding (10x that of insulin detemir). Three amino acid substitutions (A14E, B16H and B25H) ensure reduced enzymatic degradation of icodec and contribute to attenuating insulin receptor (IR) binding and clearance, further prolonging the half-life. In vitro studies demonstrated that icodec is a specific and full agonist of the human IR, and that it displays the same dose-dependent mode of action as HI, exemplified by its ability to phosphorylate the IR and stimulate intracellular signaling pathways (phospho-AKT and -ERK). Functional assays have demonstrated that icodec elicits the same pattern of metabolic effects as HI, including glucose uptake and lipogenesis in fat cells, and stimulation of glycogen synthesis in liver cells. The affinity of icodec for the IGF-1 receptor was found to be proportionately lower than its binding to the IR. The in vitro mitogenic effect of icodec in primary human mammary cells (HMEC), as well as in mammary and colon carcinoma cells (MCF-7 and COLO 205) was found to be low relative to that of HI. In conclusion, icodec is a new insulin analog designed to achieve a slowly cleared, albumin-bound circulating depot which results in a long half-life suited for once weekly injections, covering the basal insulin requirements for a full week. *Insulin icodec (proposed INN). Disclosure E. Nishimura: Employee; Self; Novo Nordisk A/S. Stock/Shareholder; Self; Novo Nordisk A/S. Stock/Shareholder; Spouse/Partner; Novo Nordisk A/S. T. Kjeldsen: Employee; Self; Novo Nordisk A/S. Stock/Shareholder; Self; Novo Nordisk A/S. Stock/Shareholder; Spouse/Partner; Novo Nordisk A/S. F. Hubalek: Employee; Self; Novo Nordisk A/S. Stock/Shareholder; Self; Novo Nordisk A/S. T. Glendorf: Employee; Spouse/Partner; Novo Nordisk A/S. Employee; Self; Novo Nordisk A/S. Stock/Shareholder; Spouse/Partner; Novo Nordisk A/S. Stock/Shareholder; Self; Novo Nordisk A/S. C.E. Stidsen: Employee; Self; Novo Nordisk A/S. Stock/Shareholder; Self; Novo Nordisk A/S. B.F. Hansen: Stock/Shareholder; Self; Novo Nordisk A/S. T.A. Pedersen: Employee; Self; Novo Nordisk A/S. A. Luetzen: Employee; Self; Novo Nordisk A/S. Stock/Shareholder; Self; Novo Nordisk A/S. L. Pridal: None. P. Madsen: Employee; Self; Novo Nordisk A/S.

Abstract B119: Receptiveness of metformin as a breast cancer prevention drug within the Hispanic community

Abstract Despite cancer being the leading cause of death across most racial/ethnic groups, Hispanic women have the second highest mortality rate attributed to diabetes (4.7%) according to the Centers for Disease Control and Prevention (CDC). While cancer and diabetes are two distinct diseases, previous studies have demonstrated that diabetic women have a poor chance of breast cancer survival when compared to nondiabetic women. Well-known key drivers of hyperinsulinemia and insulin resistance, such as insulin and AMPK, are also those involved in breast cancer. This link could possibly contribute to the increased mitogenic effects and risk for aggressive breast cancers in Hispanic women. Based on these findings, metformin, a drug standardly used to treat and prevent hyperglycemia, may be a possible alternative (other than tamoxifen) for breast cancer prevention. Eat, Move, Live (EML), a 5-week community-based program, focuses on targeting possible treatments of chronic diseases and risk reduction through attitude and lifestyle modifications. Exercise, nutritional and health awareness classes were implemented to change participants' perspectives regarding chronic diseases and their susceptibility to other morbidities. Questionnaires were given to the participants at baseline and at two follow-ups (5 weeks and 12 weeks) to assess any changes in their attitudes, behaviors, nutrition, lifestyle and beliefs around taking medication for preventative treatments. A total of 56 participants' pretreatment responses were collected via a five-point Likert scale (1-strongly disagree, 5-strongly agree). Demographic data showed that 69% of the respondents were Hispanic women, of whom 46% completed an education level of high school or less. A majority of the responses averaged a “neutral” response to taking medication for management and prevention of diabetes. We infer that their inability to select a stance in their responses may be associated with the lack of knowledge that the community has regarding chronic diseases and risk-prevention methods. Therefore, we anticipate that availability of proper education tools and resources is essential to potentially prevent future morbidities and mortalities. Ultimately, we aim to establish a pilot study that emphasizes the necessity and importance of interventional programs, like EML, to enhance chemoprevention using metformin and improve health outcomes in high-risk breast cancer populations. Citation Format: Mayra Serrano, Angelica Sanchez, Christine Thai, Katty Nerio, Cristal Resto, Marisela Garcia, Tanya A. Chavez, Laura L. Kruper, Veronica C. Jones, Lisa D. Yee, Alan Nuñez, Ellen J. Rippberger, Angela K. Wong, Noé R. Chávez, Karen Herold, Chidimma M.K. Kalu, Jackelyn A. Alva-Ornelas, Jerneja Tomsic, Krista M. Round, Regina Agulto, Margarita Robles, Ombeni M. Idassi, Kendall J. Kennedy, Christopher Sistrunk, Victoria L. Seewaldt. Receptiveness of metformin as a breast cancer prevention drug within the Hispanic community [abstract]. In: Proceedings of the Eleventh AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2018 Nov 2-5; New Orleans, LA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl):Abstract nr B119.

Diabetes as a Risk Factor for Breast Cancer.

Diabetes is one of the most important chronic conditions worldwide, and breast cancer is the most prevalent cancer in women worldwide. Several types of research have been conducted to ascertain the link between diabetes and its potential for increasing the risk of breast cancer. This research aims to determine the relationship between diabetes and breast cancer; patients with diabetes have a higher risk than the general population of developing cancer, and diabetes patients have a higher incidence and mortality of breast cancer. This research also reviewed the relationship between cytokines, the mitogenic effect of insulin-like growth factors, and breast cells. The review includes searching the PubMed database using the keywords “diabetes,” “breast cancer,” “risk factor,” and “premenopausal.” The search returned 53 articles used for review of this article.

Effect of High-Dose Topical Minoxidil on Erythrocyte Quality in SKH1 Hairless Mice.

Simple SummaryIn any animal species, involuntary exposure to unknown agents may increase genetic material damage. This genetic damage can also induce the appearance of diseases such as cancer or other pathologies, including problems that can be passed on to the offspring of the damaged individual. For instance, living organisms may be affected due to the use of medications or exposure to certain chemical, physical, or biological agents which cause cell failure. This impaired function acts as an indicator that helps identify and evaluate damage in order to avoid or minimize it. In this work, excessive doses of a cosmetic drug for topical use in dermatological treatments, known as minoxidil, produced defects in the blood of hairless mice, particularly in red cells, indicating loss of DNA, a situation that may compromise life or the offspring by causing damage to their genetic material. It is important to consider that compounds may be tissue- or species-specific, although we cannot rule out the possibility that similar damage could occur in other animal species. Thus, excessive exposure to this compound should be prevented.SKH1 hairless mice are widely used in carcinogenesis and dermatology research due to their bare skin, as exposure to different agents is facilitated. Minoxidil is a cosmetic drug that is recognized as a mitogenic agent, and mitogens are suggested to have carcinogenic and mutagenic potential by inducing cell division and increasing the possibility of perpetuating DNA damage. Therefore, we hypothesized that the application of high doses of minoxidil to the skin of hairless mice would increase the number of micronucleated erythrocytes (MNEs) in peripheral blood. The objective of this study was to evaluate the topical administration of high doses of minoxidil on peripheral blood erythrocytes of SKH1 mice by means of micronucleus assay. Minoxidil was administered on the entire body surface of mice every 12 or 24 h. Minoxidil dosing every 24 h increased the number of micronucleated polychromatic erythrocytes (MNPCEs), and dosing every 12 h increased the number of MNEs and MNPCEs, as compared to baseline and the negative control group. No decrease in polychromatic erythrocyte frequencies was observed in the minoxidil groups. Therefore, topical application of high minoxidil doses to mice can produce DNA damage, as observed through an increase in the number of MNEs, without producing cytotoxicity, possibly due to its mitogenic effect.