Adult neural stem cell activation in mice is regulated by the day/night cycle and intracellular calcium dynamics.

Neural stem cells (NSCs) in the adult brain transit from the quiescent state to proliferation to produce new neurons. The mechanisms regulating this transition in freely behaving animals are, however, poorly understood. We customized in vivo imaging protocols to follow NSCs for several days up to months, observing their activation kinetics in freely behaving mice. Strikingly, NSC division is more frequent during daylight and is inhibited by darkness-induced melatonin signaling. The inhibition of melatonin receptors affected intracellular Ca2+ dynamics and promoted NSC activation. We further discovered a Ca2+ signature of quiescent versus activated NSCs and showed that several microenvironmental signals converge on intracellular Ca2+ pathways to regulate NSC quiescence and activation. In vivo NSC-specific optogenetic modulation of Ca2+ fluxes to mimic quiescent-state-like Ca2+ dynamics in freely behaving mice blocked NSC activation and maintained their quiescence, pointing to the regulatory mechanisms mediating NSC activation in freely behaving animals.

Pan-KRAS inhibitor disables oncogenic signalling and tumour growth.

KRAS is one of the most commonly mutated proteins in cancer, and efforts to directly inhibit its function have been continuing for decades. The most successful of these has been the development of covalent allele-specific inhibitors that trap KRAS G12C in its inactive conformation and suppress tumour growth in patients1-7. Whether inactive-state selective inhibition can be used to therapeutically target non-G12C KRAS mutants remains under investigation. Here we report the discovery and characterization of a non-covalent inhibitor that binds preferentially and with high affinity to the inactive state of KRAS while sparing NRAS and HRAS. Although limited to only a few amino acids, the evolutionary divergence in the GTPase domain of RAS isoforms was sufficient to impart orthosteric and allosteric constraints for KRAS selectivity. The inhibitor blocked nucleotide exchange to prevent the activation of wild-type KRAS and a broad range of KRAS mutants, including G12A/C/D/F/V/S, G13C/D, V14I, L19F, Q22K, D33E, Q61H, K117N and A146V/T. Inhibition of downstream signalling and proliferation was restricted to cancer cells harbouring mutant KRAS, and drug treatment suppressed KRAS mutant tumour growth in mice, without having a detrimental effect on animal weight. Our study suggests that most KRAS oncoproteins cycle between an active state and an inactive state in cancer cells and are dependent on nucleotide exchange for activation. Pan-KRAS inhibitors, such as the one described here, have broad therapeutic implications and merit clinical investigation in patients with KRAS-driven cancers.

Control of microtubule organization and dynamics: two ends in the limelight.

Microtubules have fundamental roles in many essential biological processes, including cell division and intracellular transport. They assemble and disassemble from their two ends, denoted the plus end and the minus end. Significant advances have been made in our understanding of microtubule plus-end-tracking proteins (+TIPs) such as end-binding protein 1 (EB1), XMAP215, selected kinesins and dynein. By contrast, information on microtubule minus-end-targeting proteins (-TIPs), such as the calmodulin-regulated spectrin-associated proteins (CAMSAPs) and Patronin, has only recently started to emerge. Here, we review our current knowledge of factors, including microtubule-targeting agents, that associate with microtubule ends to control the dynamics and function of microtubules during the cell cycle and development.

Corticosterone inhibits GAS6 to govern hair follicle stem-cell quiescence.

Chronic, sustained exposure to stressors can profoundly affect tissue homeostasis, although the mechanisms by which these changes occur are largely unknown. Here we report that the stress hormone corticosterone-which is derived from the adrenal gland and is the rodent equivalent of cortisol in humans-regulates hair follicle stem cell (HFSC) quiescence and hair growth in mice. In the absence of systemic corticosterone, HFSCs enter substantially more rounds of the regeneration cycle throughout life. Conversely, under chronic stress, increased levels of corticosterone prolong HFSC quiescence and maintain hair follicles in an extended resting phase. Mechanistically, corticosterone acts on the dermal papillae to suppress the expression of Gas6, a gene that encodes the secreted factor growth arrest specific 6. Restoring Gas6 expression overcomes the stress-induced inhibition of HFSC activation and hair growth. Our work identifies corticosterone as a systemic inhibitor of HFSC activity through its effect on the niche, and demonstrates that the removal of such inhibition drives HFSCs into frequent regeneration cycles, with no observable defects in the long-term.

Gamblers: An Antibiotic-Induced Evolvable Cell Subpopulation Differentiated by Reactive-Oxygen-Induced General Stress Response.

Antibiotics can induce mutations that cause antibiotic resistance. Yet, despite their importance, mechanisms of antibiotic-promoted mutagenesis remain elusive. We report that the fluoroquinolone antibiotic ciprofloxacin (cipro) induces mutations by triggering transient differentiation of a mutant-generating cell subpopulation, using reactive oxygen species (ROS). Cipro-induced DNA breaks activate the Escherichia coli SOS DNA-damage response and error-prone DNA polymerases in all cells. However, mutagenesis is limited to a cell subpopulation in which electron transfer together with SOS induce ROS, which activate the sigma-S (σS) general-stress response, which allows mutagenic DNA-break repair. When sorted, this small σS-response-"on" subpopulation produces most antibiotic cross-resistant mutants. A U.S. Food and Drug Administration (FDA)-approved drug prevents σS induction, specifically inhibiting antibiotic-promoted mutagenesis. Further, SOS-inhibited cell division, which causes multi-chromosome cells, promotes mutagenesis. The data support a model in which within-cell chromosome cooperation together with development of a "gambler" cell subpopulation promote resistance evolution without risking most cells.

Serine restriction alters sphingolipid diversity to constrain tumour growth.

Serine, glycine and other nonessential amino acids are critical for tumour progression, and strategies to limit their availability are emerging as potential therapies for cancer1-3. However, the molecular mechanisms driving this response remain unclear and the effects on lipid metabolism are relatively unexplored. Serine palmitoyltransferase (SPT) catalyses the de novo biosynthesis of sphingolipids but also produces noncanonical 1-deoxysphingolipids when using alanine as a substrate4,5. Deoxysphingolipids accumulate in the context of mutations in SPTLC1 or SPTLC26,7-or in conditions of low serine availability8,9-to drive neuropathy, and deoxysphinganine has previously been investigated as an anti-cancer agent10. Here we exploit amino acid metabolism and the promiscuity of SPT to modulate the endogenous synthesis of toxic deoxysphingolipids and slow tumour progression. Anchorage-independent growth reprogrammes a metabolic network involving serine, alanine and pyruvate that drives the endogenous synthesis and accumulation of deoxysphingolipids. Targeting the mitochondrial pyruvate carrier promotes alanine oxidation to mitigate deoxysphingolipid synthesis and improve spheroid growth, similar to phenotypes observed with the direct inhibition of SPT or ceramide synthesis. Restriction of dietary serine and glycine potently induces the accumulation of deoxysphingolipids while decreasing tumour growth in xenograft models in mice. Pharmacological inhibition of SPT rescues xenograft growth in mice fed diets restricted in serine and glycine, and the reduction of circulating serine by inhibition of phosphoglycerate dehydrogenase (PHGDH) leads to the accumulation of deoxysphingolipids and mitigates tumour growth. The promiscuity of SPT therefore links serine and mitochondrial alanine metabolism to membrane lipid diversity, which further sensitizes tumours to metabolic stress.

Response surface methodology mediated optimization of phytosulfokine and plant growth regulators for enhanced protoplast division, callus induction, and somatic embryogenesis in Angelica Gigas Nakai.

BACKGROUND: Angelica Gigas (Purple parsnip) is an important medicinal plant that is cultivated and utilized in Korea, Japan, and China. It contains bioactive substances especially coumarins with anti-inflammatory, anti-platelet aggregation, anti-cancer, anti-diabetic, antimicrobial, anti-obesity, anti-oxidant, immunomodulatory, and neuroprotective properties. This medicinal crop can be genetically improved, and the metabolites can be obtained by embryonic stem cells. In this context, we established the protoplast-to-plant regeneration methodology in Angelica gigas. RESULTS: In the present investigation, we isolated the protoplast from the embryogenic callus by applying methods that we have developed earlier and established protoplast cultures using Murashige and Skoog (MS) liquid medium and by embedding the protoplast in thin alginate layer (TAL) methods. We supplemented the culture medium with growth regulators namely 2,4-dichlorophenoxyaceticacid (2,4-D, 0, 0.75, 1.5 mg L- 1), kinetin (KN, 0, 0.5, and 1.0 mg L- 1) and phytosulfokine (PSK, 0, 50, 100 nM) to induce protoplast division, microcolony formation, and embryogenic callus regeneration. We applied central composite design (CCD) and response surface methodology (RSM) for the optimization of 2,4-D, KN, and PSK levels during protoplast division, micro-callus formation, and induction of embryogenic callus stages. The results revealed that 0.04 mg L- 1 2,4-D + 0.5 mg L- 1 KN + 2 nM PSK, 0.5 mg L- 1 2,4-D + 0.9 mg L- 1 KN and 90 nM PSK, and 1.5 mg L- 1 2,4-D and 1 mg L- 1 KN were optimum for protoplast division, micro-callus formation and induction embryogenic callus. MS basal semi-solid medium without growth regulators was good for the development of embryos and plant regeneration. CONCLUSIONS: This study demonstrated successful protoplast culture, protoplast division, micro-callus formation, induction embryogenic callus, somatic embryogenesis, and plant regeneration in A. gigas. The methodologies developed here are quite useful for the genetic improvement of this important medicinal plant.

Distinct signaling by insulin and IGF-1 receptors and their extra- and intracellular domains.

Insulin and insulin-like growth factor 1 (IGF-1) receptors share many downstream signaling pathways but have unique biological effects. To define the molecular signals contributing to these distinct activities, we performed global phosphoproteomics on cells expressing either insulin receptor (IR), IGF-1 receptor (IGF1R), or chimeric IR-IGF1R receptors. We show that IR preferentially stimulates phosphorylations associated with mammalian target of rapamycin complex 1 (mTORC1) and Akt pathways, whereas IGF1R preferentially stimulates phosphorylations on proteins associated with the Ras homolog family of guanosine triphosphate hydrolases (Rho GTPases), and cell cycle progression. There were also major differences in the phosphoproteome between cells expressing IR versus IGF1R in the unstimulated state, including phosphorylation of proteins involved in membrane trafficking, chromatin remodeling, and cell cycle. In cells expressing chimeric IR-IGF1R receptors, these differences in signaling could be mapped to contributions of both the extra- and intracellular domains of these receptors. Thus, despite their high homology, IR and IGF1R preferentially regulate distinct networks of phosphorylation in both the basal and stimulated states, allowing for the unique effects of these hormones on organismal function.

How cortical waves drive fission of motile cells.

Cytokinesis-the division of a cell into two daughter cells-is a key step in cell growth and proliferation. It typically occurs in synchrony with the cell cycle to ensure that a complete copy of the genetic information is passed on to the next generation of daughter cells. In animal cells, cytokinesis commonly relies on an actomyosin contractile ring that drives equatorial furrowing and separation into the two daughter cells. However, also contractile ring-independent forms of cell division are known that depend on substrate-mediated traction forces. Here, we report evidence of an as yet unknown type of contractile ring-independent cytokinesis that we termed wave-mediated cytofission. It is driven by self-organized cortical actin waves that travel across the ventral membrane of oversized, multinucleated Dictyostelium discoideum cells. Upon collision with the cell border, waves may initiate the formation of protrusions that elongate and eventually pinch off to form separate daughter cells. They are composed of a stable elongated wave segment that is enclosed by a cell membrane and moves in a highly persistent fashion. We rationalize our observations based on a noisy excitable reaction-diffusion model in combination with a dynamic phase field to account for the cell shape and demonstrate that daughter cells emerging from wave-mediated cytofission exhibit a well-controlled size.

From one cell to many: Morphogenetic field of lateral root founder cells in Arabidopsis thaliana is built by gradual recruitment.

The reiterative process of lateral root (LR) formation is widespread and underlies root system formation. However, early LR primordium (LRP) morphogenesis is not fully understood. In this study, we conducted both a clonal analysis and time-lapse experiments to decipher the pattern and sequence of pericycle founder cell (FC) participation in LR formation. Most commonly, LRP initiation starts with the specification of just one FC longitudinally. Clonal and anatomical analyses suggested that a single FC gradually recruits neighboring pericycle cells to become FCs. This conclusion was validated by long-term time-lapse live-imaging experiments. Once the first FC starts to divide, its immediate neighbors, both lengthwise and laterally, are recruited within the hour, after which they recruit their neighboring cells within a few hours. Therefore, LRP initiation is a gradual, multistep process. FC recruitment is auxin-dependent and is abolished by treatment with a polar auxin transport inhibitor. Furthermore, FC recruitment establishes a morphogenetic field where laterally peripheral cells have a lower auxin response, which is associated with a lower proliferation potential, compared to centrally located FCs. The lateral boundaries of the morphogenetic field are determined by phloem-adjacent pericycle cells, which are the last cells to be recruited as FCs. The proliferation potential of these cells is limited, but their recruitment is essential for root system formation, resulting in the formation of a new vascular connection between the nascent and parent root, which is crucial for establishing a continuous and efficient vascular system.

Aneuploidy increases resistance to chemotherapeutics by antagonizing cell division.

Aneuploidy, defined as whole chromosome gains and losses, is associated with poor patient prognosis in many cancer types. However, the condition causes cellular stress and cell cycle delays, foremost in G1 and S phase. Here, we investigate how aneuploidy causes both slow proliferation and poor disease outcome. We test the hypothesis that aneuploidy brings about resistance to chemotherapies because of a general feature of the aneuploid condition-G1 delays. We show that single chromosome gains lead to increased resistance to the frontline chemotherapeutics cisplatin and paclitaxel. Furthermore, G1 cell cycle delays are sufficient to increase chemotherapeutic resistance in euploid cells. Mechanistically, G1 delays increase drug resistance to cisplatin and paclitaxel by reducing their ability to damage DNA and microtubules, respectively. Finally, we show that our findings are clinically relevant. Aneuploidy correlates with slowed proliferation and drug resistance in the Cancer Cell Line Encyclopedia (CCLE) dataset. We conclude that a general and seemingly detrimental effect of aneuploidy, slowed proliferation, provides a selective benefit to cancer cells during chemotherapy treatment.

The BET inhibitor CPI203 promotes ex vivo expansion of cord blood long-term repopulating HSCs and megakaryocytes.

Although cytokine-mediated expansion of human hematopoietic stem cells (HSCs) can result in high yields of hematopoietic progenitor cells, this generally occurs at the expense of reduced bone marrow HSC repopulating ability, thereby limiting potential therapeutic applications. Because bromodomain-containing proteins (BCPs) have been demonstrated to regulate mouse HSC self-renewal and stemness, we screened small molecules targeting various BCPs as potential agents for ex vivo expansion of human HSCs. Of 10 compounds tested, only the bromodomain and extra-terminal motif inhibitor CPI203 enhanced the expansion of human cord blood HSCs without losing cell viability in vitro. The expanded cells also demonstrated improved engraftment and repopulation in serial transplantation assays. Transcriptomic and functional studies showed that the expansion of long-term repopulating HSCs was accompanied by synchronized expansion and maturation of megakaryocytes consistent with CPI203-mediated reprogramming of cord blood hematopoietic stem and progenitor cells. This approach may therefore prove beneficial for ex vivo gene editing, for enhanced platelet production, and for the improved usage of cord blood for transplantation research and therapy.

Targeting PTPRK-RSPO3 colon tumours promotes differentiation and loss of stem-cell function.

Colorectal cancer remains a major unmet medical need, prompting large-scale genomics efforts in the field to identify molecular drivers for which targeted therapies might be developed. We previously reported the identification of recurrent translocations in R-spondin genes present in a subset of colorectal tumours. Here we show that targeting RSPO3 in PTPRK-RSPO3-fusion-positive human tumour xenografts inhibits tumour growth and promotes differentiation. Notably, genes expressed in the stem-cell compartment of the intestine were among those most sensitive to anti-RSPO3 treatment. This observation, combined with functional assays, suggests that a stem-cell compartment drives PTPRK-RSPO3 colorectal tumour growth and indicates that the therapeutic targeting of stem-cell properties within tumours may be a clinically relevant approach for the treatment of colorectal tumours.

The tyrosine kinase v-Src modifies cytotoxicities of anticancer drugs targeting cell division.

v-Src oncogene causes cell transformation through its strong tyrosine kinase activity. We have revealed that v-Src-mediated cell transformation occurs at a low frequency and it is attributed to mitotic abnormalities-mediated chromosome instability. v-Src directly phosphorylates Tyr-15 of cyclin-dependent kinase 1 (CDK1), thereby causing mitotic slippage and reduction in Eg5 inhibitor cytotoxicity. However, it is not clear whether v-Src modifies cytotoxicities of the other anticancer drugs targeting cell division. In this study, we found that v-Src restores cancer cell viability reduced by various microtubule-targeting agents (MTAs), although v-Src does not alter cytotoxicity of DNA-damaging anticancer drugs. v-Src causes mitotic slippage of MTAs-treated cells, consequently generating proliferating tetraploid cells. We further demonstrate that v-Src also restores cell viability reduced by a polo-like kinase 1 (PLK1) inhibitor. Interestingly, treatment with Aurora kinase inhibitor strongly induces cell death when cells express v-Src. These results suggest that the v-Src modifies cytotoxicities of anticancer drugs targeting cell division. Highly activated Src-induced resistance to MTAs through mitotic slippage might have a risk to enhance the malignancy of cancer cells through the increase in chromosome instability upon chemotherapy using MTAs.

Fundamental mechanisms of the stem cell regulation in land plants: lesson from shoot apical cells in bryophytes.

KEY MESSAGE: This review compares the molecular mechanisms of stem cell control in the shoot apical meristems of mosses and angiosperms and reveals the conserved features and evolution of plant stem cells. The establishment and maintenance of pluripotent stem cells in the shoot apical meristem (SAM) are key developmental processes in land plants including the most basal, bryophytes. Bryophytes, such as Physcomitrium (Physcomitrella) patens and Marchantia polymorpha, are emerging as attractive model species to study the conserved features and evolutionary processes in the mechanisms controlling stem cells. Recent studies using these model bryophyte species have started to uncover the similarities and differences in stem cell regulation between bryophytes and angiosperms. In this review, we summarize findings on stem cell function and its regulation focusing on different aspects including hormonal, genetic, and epigenetic control. Stem cell regulation through auxin, cytokinin, CLAVATA3/EMBRYO SURROUNDING REGION-RELATED (CLE) signaling and chromatin modification by Polycomb Repressive Complex 2 (PRC2) and PRC1 is well conserved. Several transcription factors crucial for SAM regulation in angiosperms are not involved in the regulation of the SAM in mosses, but similarities also exist. These findings provide insights into the evolutionary trajectory of the SAM and the fundamental mechanisms involved in stem cell regulation that are conserved across land plants.

New insights into HDV persistence: The role of interferon response and implications for upcoming novel therapies.

Chronic hepatitis D (CHD), a global health problem, manifests as the most severe form of viral hepatitis. The causative agent, HDV, is the smallest known human virus; it replicates its circular single-stranded RNA genome in the nucleus of hepatocytes. HDV requires HBV-encoded envelope proteins for dissemination and de novo cell entry. However, HDV can also spread through cell division. Following entry into hepatocytes, replicative intermediates of HDV RNA are sensed by the pattern recognition receptor MDA5 (melanoma differentiation antigen 5) resulting in interferon (IFN)-ß/λ induction. This IFN response strongly suppresses cell division-mediated spread of HDV genomes, however, it only marginally affects HDV RNA replication in already infected, resting hepatocytes. Monotherapy with IFN-α/λ shows efficacy but rarely results in HDV clearance. Recent molecular insights into key determinants of HDV persistence and the accelerated development of specifically acting antivirals that interfere with the replication cycle have revealed promising new therapeutic perspectives. In this review, we briefly summarise our knowledge on replication/persistence of HDV, the newly discovered HDV-like agents, and the interplay of HDV with the IFN response and its consequences for persistence. Finally, we discuss the possible role of IFNs in combination with upcoming therapies aimed at HDV cure.

CDK1 inhibitor controls G2/M phase transition and reverses DNA damage sensitivity.

CDK1 plays key roles in cell cycle progression through the G2/M phase transition and activation of homologous recombination (HR) DNA repair pathway. Accordingly, various CDK1 inhibitors have been developed for cancer therapy that induce prolonged G2 arrest and/or sensitize cells to DNA damaging agents in tumor cells, resulting in cell death. However, CDK1 inhibition can induce resistance to DNA damage in certain conditions. The mechanism of different DNA damage sensitivity is not completely understood. We performed immunofluorescence and flow cytometry analysis to investigate DNA damage responses in human tumor cells during low and high dose treatments with RO-3306, a selective CDK1 inhibitor. This comparative investigation demonstrated that RO-3306-induced G2 arrest prevented cells with DNA double-strand breaks from transitioning into the M-phase and that the cells maintained their DNA repair capacity in G2-phase, even under RO-3306 dose-dependent DNA repair inhibition. These findings reveal that CDK1 inhibitor-induced DNA repair inhibition and cell cycle control, which regulate each other during the G2/M phase transition determine the cellular sensitivity to DNA damage, providing insight useful for developing clinical strategies targeting CDK1 inhibition in tumor cells.

The study of 9,10-dihydroacridine derivatives as a new and effective molecular scaffold for antibacterial agent development.

The emergence of worldwide spreading drug-resistant bacteria has been a serious threat to public health during the past decades. The development of new and effective antibacterial agents to address this critical issue is an urgent action. In the present study, we investigated the antibacterial activity of two 9,10-dihydroacridine derivatives and their mechanism. Both compounds were found possessing strong antibacterial activity against some selected Gram-positive bacteria including MRSA, VISA and VRE. The biological study suggests that the compounds promoted FtsZ polymerization and also disrupted Z-ring formation at the dividing site and consequently, the bacterial cell division is interrupted and causing cell death.

Methylation Status of the miR-141-3p Promoter Regulates miR-141-3p Expression, Inflammasome Formation, and the Invasiveness of HTR-8/SVneo Cells.

MicroRNA-141 (miR-141-3p) is upregulated in preeclampsia. This study investigated the effect of methylation of the miR-141-3p promoter on cell viability, invasion capability, and inflammasomes in vitro. The expression of miR-141-3p and methylation status of the miR-141-3p promoter were examined by RT-qPCR and pyrosequencing in villus tissues of women with spontaneous delivery (VTsd), villus tissues of women with preeclampsia (VTpe), and also in HTR-8/SVneo cells treated with a miR-141-3p inhibitor and 20 µmol/L 5-aza-2'-deoxycytidine (5-Aza), a DNA methyltransferase inhibitor. Cell viability and invasion were evaluated by CCK-8 and transwell assays. In addition, the levels of CXCL12, CXCR4, CXCR2, MMPs, NLRP3, and ASC expression were assessed by western blotting, and IL-1ß and IL-18 concentrations were assayed by ELISA. miR-141-3p expression was upregulated, and the levels of miR-141-3p promoter methylation and CXCL12, CXCR4, and CXCR2 expression were decreased in VTpe relative to VTsd. In HTR-8/SVneo cells, hypomethylation caused by 5-Aza treatment increased miR-141-3p expression, while DNA methyltransferase 3 (DNMT3) transfection decreased miR-141-3p expression. miRNA-141-3p induced NLRP3, IL-1ß, and IL-18 production, decreased CXCR4, MMP, and MMP2 production, and suppressed cell growth and invasion. Furthermore, we observed that NLRP3 plays an important mediatory role in the effects of miR-141-3p described above. Decreased methylation of the miR-141-3p promoter increases miR-141-3p expression, which in turn increases NLRP3 expression, resulting in higher IL-1ß and IL-18 levels and lower levels of MMP2/9 and CXCR4. We conclude that modification of the miR-141-3p promoter might be a curial mediator in preeclampsia.

Upregulated Talin1 synergistically boosts ß-estradiol-induced proliferation and pro-angiogenesis of eutopic and ectopic endometrial stromal cells in adenomyosis.

Adenomyosis (ADS) is an estrogen-dependent gynecological disease with unspecified etiopathogenesis. Local hyperestrogenism may serve a key role in contributing to the origin of ADS. Talin1 is mostly identified to be overexpressed and involved in the progression of numerous human carcinomas through mediating cell proliferation, adhesion and motility. Whether Talin1 exerts an oncogenic role in the pathogenesis of ADS and puts an extra impact on the efficacy of estrogen, no relevant data are available yet. Here we demonstrated that the adenomyotic eutopic and ectopic endometrial stromal cells (ADS_Eu_ESC and ADS_Ec_ESC) treated with ß-estradiol (ß-E2) presented stronger proliferative and pro-angiogenetic capacities, accompanied by increased expression of PCNA, Ki67, VEGFB and ANGPTL4 proteins. Meanwhile, these promoting effects were partially abrogated by Fulvestrant (ICI 182780, an estrogen-receptor antagonist). Aberrantly upregulation of Talin1 mRNA and protein level was observed in ADS endometrial specimens and stromal cells. Through performing functional experiments in vitro, we further determined that merely overexpression of Talin1 (OV-Talin1) also enhanced ADS stromal cell proliferation and pro-angiogenesis, while the most pronounced facilitating effects were found in the co-intervention group of OV-Talin1 plus ß-E2 treatment. Results from the xenograft nude mice model showed that the hypodermic endometrial lesions from co-intervention group had the highest mean weight and volume, compared with that of individual OV-Talin1 or ß-E2 treatment. The expression levels of PCNA, Ki67, VEGFB and ANGPTL4 in the lesions were correspondingly elevated the most in the co-intervention group. Our findings unveiled that overexpressed Talin1 might cooperate withß-E2 in stimulating ADS endometrial stromal cell proliferation and neovascularization, synergistically promoting the growth and survival of ectopic lesions. These results may be beneficial to provide a new insight for clarifying the pathogenesis of ADS.