Autocrine Growth Factor Research Articles

AI-Enabled Ultra-large Virtual Screening Identifies Potential Inhibitors of Choline Acetyltransferase for Theranostic Purposes.

Alzheimer's disease (AD) and related dementias are among the primary neurological disorders and call for the urgent need for early-stage diagnosis to gain an upper edge in therapeutic intervention and increase the overall success rate. Choline acetyltransferase (ChAT) is the key acetylcholine (ACh) biosynthesizing enzyme and a legitimate target for the development of biomarkers for early-stage diagnosis and monitoring of therapeutic responses. It is also a theranostic target for tackling colon and lung cancers, where overexpression of non-neuronal ChAT leads to the production of acetylcholine, which acts as an autocrine growth factor for cancer cells. Theranostics is a hybrid of diagnostics and therapeutics that can be used to locate cancer cells using radiotracers and kill them without affecting other healthy tissues. Traditional virtual screening protocols have a lot of limitations; given the current rate of chemical database expansion exceeding billions, much faster screening protocols are required. Deep docking (DD) is one such platform that leverages the power of deep neural network (DNN)-based virtual screening, empowering researchers to dock billions of molecules in a speedy, yet explicit manner. Here, we have screened 1.3 billion compounds library from the ZINC20 database, identifying the best-performing hits. With each iteration run where the first iteration gave ∼116 million hits, the second iteration gave ∼3.7 million hits, and the final third iteration gave 168,447 hits from which further refinement gave us the top 5 compounds as potential ChAT inhibitors. The discovery of novel ChAT inhibitors will enable researchers to develop new probes that can be used as novel theranostic agents against cancer and as early-stage diagnostics for the onset of AD, for timely therapeutic intervention to halt the further progression of AD.

Resuscitation Promotion Factor: A Pronounced Bacterial Cytokine in Propelling Bacterial Resuscitation.

While confronted with unfavorable growth conditions, bacteria may transform into the dormant state, such as viable but nonculturable (VBNC) state, which is a reversible state characterized by low metabolic activity and lack of division. These dormant cells can be reactivated through the influence of the resuscitation promoting factor (Rpf) family, which are classified as autocrine growth factors and possess peptidoglycan hydrolase activities. To date, with the significant resuscitation or growth promotion ability of Rpf, it has been extensively applied to increasing bacterial diversity and isolating functional microbial species. This review provides a comprehensive analysis of the distribution, mode of action, and functional mechanisms of Rpf proteins in various bacterial species. The aim is to create opportunities for decoding microbial communities and extracting microbial resources from real samples across different research fields.

Clinically-observed FOXA1 mutations upregulate SEMA3C through transcriptional derepression in prostate cancer

FOXA1 is a pioneer transcription factor that is frequently mutated in prostate, breast, bladder, and salivary gland malignancies. Indeed, metastatic castration-resistant prostate cancer (mCRPC) commonly harbour FOXA1 mutations with a prevalence of 35%. However, despite the frequent recurrence of FOXA1 mutations in prostate cancer, the mechanisms by which FOXA1 variants drive its oncogenic effects are still unclear. Semaphorin 3C (SEMA3C) is a secreted autocrine growth factor that drives growth and treatment resistance of prostate and other cancers and is known to be regulated by both AR and FOXA1. In the present study, we characterize FOXA1 alterations with respect to its regulation of SEMA3C. Our findings reveal that FOXA1 alterations lead to elevated levels of SEMA3C both in prostate cancer specimens and in vitro. We further show that FOXA1 negatively regulates SEMA3C via intronic cis elements, and that mutations in FOXA1 forkhead domain attenuate its inhibitory function in reporter assays, presumably by disrupting DNA binding of FOXA1. Our findings underscore the key role of FOXA1 in prostate cancer progression and treatment resistance by regulating SEMA3C expression and suggest that SEMA3C may be a driver of growth and tumor vulnerability of mCRPC harboring FOXA1 alterations.

Impact of Bmal1 Rescue and Time-Restricted Feeding on Liver and Muscle Proteomes During the Active Phase in Mice

Molecular clocks and daily feeding cycles support metabolism in peripheral tissues. Although the roles of local clocks and feeding are well defined at the transcriptional level, their impact on governing protein abundance in peripheral tissues is unclear. Here, we determine the relative contributions of local molecular clocks and daily feeding cycles on liver and muscle proteomes during the active phase in mice. LC-MS/MS was performed on liver and gastrocnemius muscle harvested 4 h into the dark phase from WT, Bmal1 KO, and dual liver- and muscle-Bmal1-rescued mice under either ad libitum feeding or time-restricted feeding during the dark phase. Feeding-fasting cycles had only minimal effects on levels of liver proteins and few, if any, on the muscle proteome. In contrast, Bmal1 KO altered the abundance of 674 proteins in liver and 80 proteins in muscle. Local rescue of liver and muscle Bmal1 restored ∼50% of proteins in liver and ∼25% in muscle. These included proteins involved in fatty acid oxidation in liver and carbohydrate metabolism in muscle. For liver, proteins involved in de novo lipogenesis were largely dependent on Bmal1 function in other tissues (i.e., the wider clock system). Proteins regulated by BMAL1 in liver and muscle were enriched for secreted proteins. We found that the abundance of fibroblast growth factor 1, a liver secreted protein, requires BMAL1 and that autocrine fibroblast growth factor 1 signaling modulates mitochondrial respiration in hepatocytes. In liver and muscle, BMAL1 is a more potent regulator of dark phase proteomes than daily feeding cycles, highlighting the need to assess protein levels in addition to mRNA when investigating clock mechanisms. The proteome is more extensively regulated by BMAL1 in liver than in muscle, and many metabolic pathways in peripheral tissues are reliant on the function of the clock system as a whole.

Over-expression by degradation rescue of RTKs via cancer-secreted autocrine growth factors: a Phospho-degron-driven actionable layer of post-translational regulation?

Recently published work provide the first known evidence of a malignancy-associated regulatory mechanism, functionally connecting a phospho-regulated degron domain embedded in a receptor tyrosine kinase (RTK), with its ectopic expression in cancer, conditional to a specific autocrine growth factor signal. Mechanistically, the growth factor-triggered phosphorylation inhibits the degron domain present in the regulated RTK, blocking access to a specific degradation complex. This ultimately rescues the RTK from rapid ubiquitin-proteasome-system-mediated degradation and, most importantly, causes its cellular overexpression. This mechanism, which has been here assigned the new functional name "Over-Expression by Degradation Rescue" (OEDR), provides an additional layer and potentially preferential tool for the control of RTKs expression in cancer, in addition to other mechanisms acting at the transcriptional and messenger transcript stabilization levels. We propose this newly defined phosphorylation/ubiquitination switch-dependent signal to bear wider unexploited relevance in cell biology and human pathophysiology. The recently identified mechanism underlying an OEDR-regulated RTK is discussed herein in the context of physiological endocrine circuits and cancer.

Mechanisms regulating wound healing: Functional changes in biology mediated by lactate and histone lactylation.

The high incidence, low healing rate and huge economic burden of wounds (especially chronic wounds) worldwide remain a great challenge for clinical staff and patients. The various stages of wound healing are regulated by paracrine or autocrine cytokines and growth factors, and the study of their intrinsic mechanisms is a prerequisite for better wound treatment. Lactate, the end product of glycolysis, plays a role in all stages of wound healing, and recent studies have identified lactate as an epigenetic regulator that regulates gene expression through histone lysine lactylation and stimulates posttranslational modifications to regulate related gene expression, thereby causing a series of biological functional changes. This article reviews the progress of research on lactate and lactylation during wound healing or in related diseases, including its involvement in immune regulation, inflammation control, and proliferative remodeling, and finally describes the prospects for lactate therapy regarding wound healing.

Dependency of Tamoxifen Sensitive and Resistant ER+ Breast Cancer Cells on Semaphorin 3C (SEMA3C) for Growth.

Estrogen receptor positive (ER+) breast cancer (BCa) accounts for the highest proportion of breast cancer-related deaths. While endocrine therapy is highly effective for this subpopulation, endocrine resistance remains a major challenge and the identification of novel targets is urgently needed. Previously, we have shown that Semaphorin 3C (SEMA3C) is an autocrine growth factor that drives the growth and treatment resistance of various cancers, but its role in breast cancer progression and endocrine resistance is poorly understood. Here, we report that SEMA3C plays a role in maintaining the growth of ER+ BCa cells and is a novel, tractable therapeutic target for the treatment of ER+ BCa patients. Analyses of publicly available clinical datasets indicate that ER+ BCa patients express significantly higher levels of SEMA3C mRNA than other subtypes. Furthermore, SEMA3C mRNA expression was positively correlated with ESR1 mRNA expression. ER+ BCa cell lines (MCF7 and T47D) expressed higher levels of SEMA3C mRNA and protein than a normal mammary epithelial MCF10A cell line. ER siRNA knockdown was suppressed, while dose-dependent beta-estradiol treatment induced SEMA3C expression in both MCF7 and T47D cells, suggesting that SEMA3C is an ER-regulated gene. The stimulation of ER+ BCa cells with recombinant SEMA3C activated MAPK and AKT signaling in a dose-dependent manner. Conversely, SEMA3C silencing inhibited Estrogen Receptor (ER) expression, MAPK and AKT signaling pathways while simultaneously inducing apoptosis, as monitored by flow cytometry and Western blot analyses. SEMA3C silencing significantly inhibited the growth of ER+ BCa cells, implicating a growth dependency of ER+ BCa cells on SEMA3C. Moreover, the analysis of tamoxifen resistant (TamR) cell models (TamC3 and TamR3) showed that SEMA3C levels remain high despite treatment with tamoxifen. Tamoxifen-resistant cells remained dependent on SEMA3C for growth and survival. Treatment with B1SP Fc fusion protein, a SEMA3C pathway inhibitor, attenuated SEMA3C-induced signaling and growth across a panel of tamoxifen sensitive and resistant ER+ breast cancer cells. Furthermore, SEMA3C silencing and B1SP treatment were associated with decreased EGFR signaling in TamR cells. Here, our study implicates SEMA3C in a functional role in ER+ breast cancer signaling and growth that suggests ER+ BCa patients may benefit from SEMA3C-targeted therapy.

Abstract OT3-16-01: On-going prospective study to measure serum progranulin/GP88 levels in metastatic breast cancer patients in association with disease status

Abstract The ability to monitor response to therapy and disease progression in metastatic breast cancer (MBC) patients is a major step in patient management. Imaging is the method of choice for the assessment of disease status and the monitoring of disease progression. However, this approach remains expensive, expose patients to radiation and thus is mainly performed every 2-3 months. During this time interval, the disease may progress significantly on ineffective treatment and the patient may present treatment related toxicities due to the inability to detect progression at earlier times. Circulating levels of tumor associated biomarkers such as CA15-3 and CEA are often determined to track disease status of MBC. However, even though they can provide information about disease progression, they do not always provide a reliable measure of response to therapy. The monitoring of disease status and progression through the measurement of drivers of disease should provide an alternative and complementary approach to existing strategies in order to better to monitor the disease status and enable proactive management of MBC patients. Progranulin also called Glycoprotein 88kDa (PGRN/GP88) is an autocrine growth factor overexpressed in breast cancer. Biological studies have established GP88 as a critical player in breast tumorigenesis. GP88 overexpression is associated with the malignant phenotype, estrogen independence, increased proliferation, survival, and drug resistance. High PGRN/GP88 tumor expression measured by immunohistochemistry in invasive ductal carcinoma is an independent prognostic marker associated with increased risk of recurrence and mortality. Clinical studies have demonstrated that GP88 circulating levels as measured by enzyme immunoassay are elevated in breast cancer patients, compared to healthy individuals. In MBC patients, circulating GP88 levels correlate with overall survival. These facts are supportive of the hypothesis that the measurement of circulating GP88 levels in MBC patients can serve as an additional biomarker to monitor MBC disease status and be predictive to outcome. A prospective study was established is to identify whether there is a statistically significant change in serum GP88 levels associated with time to progression of breast cancer as measured by RECIST 1.1 criteria in MBC patients. With the assumptions that patients will provide a baseline and four follow up visits and that 20% of the visits record a disease progression, time to progression. Taking the plausible and clinically relevant performance to be 75% sensitivity and 46% false positive, a sample of ninety patients would give 85% power. Under IRB approved protocols at the University of Maryland Greenebaum Comprehensive Cancer Center and at two Baltimore Medstar Health Facilities, a total of 103 female breast cancer patients with measurable or evaluable metastatic disease will be consented and enrolled. The patients have been re-staged within 4 weeks and will continue or begin new therapy. Currently, we have enrolled sixty-five subjects at the three facilities. In addition to standard laboratory assessment and radiographic imaging/staging every 2-3 months on study, blood samples will be collected from each patient. The samples are stored at -70C until evaluated for GP88 using a GP88 enzyme linked immunoassay. We will analyze the GP88 serum level in correlation with survival and with disease status determined as responder, stable or progressing based on the RECIST criteria. This study is supported by grant R44CA210817 from the National Cancer Institute to Ginette Serrero Principal Investigator. Citation Format: Ginette Serrero, Paula Rosenblatt, Nancy Tait, Barbara Rector, Jennifer A. Latteri, Binbin Yue, Katherine Tkaczuk. On-going prospective study to measure serum progranulin/GP88 levels in metastatic breast cancer patients in association with disease status [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr OT3-16-01.

Is Artificial Intelligence the Key to Revolutionizing Benign Prostatic Hyperplasia Diagnosis and Management?

Benign prostatic hyperplasia (BPH) is a prevalent condition among older men that is characterized by the enlargement of the prostate gland and compression of the urethra, which often results in lower urinary tract symptoms, such as frequent urination, difficulty in starting urination, and incomplete bladder emptying. The development of BPH is thought to be primarily due to an imbalance between cell proliferation and apoptosis, underlying inflammation, epithelial-to-mesenchymal transition, and local paracrine and autocrine growth factors, although the exact molecular mechanisms are not yet fully understood. Anatomical structures considered natural and benign observations can occasionally present multi-parametric magnetic resonance imaging appearances that resemble prostate cancer (PCa), posing a risk of misinterpretation and generating false-positive outcomes and subsequently, unnecessary interventions. To aid in the diagnosis of BPH, distinguish it from PCa, and assist with treatment and outcome prediction, various Artificial Intelligence (AI)-based algorithms have been proposed to assist clinicians in the medical practice. Here, we explore the results of these new technological advances and discuss their potential to enhance clinicians' cognitive abilities and expertise. There is no doubt that AI holds extensive medical potential, but the cornerstone for secure, efficient, and ethical integration into diverse medical fields still remains well-structured clinical trials.

Autocrine EGF and TGF-α promote primary and acquired resistance to ALK/c-Met kinase inhibitors in non-small-cell lung cancer.

Drug resistance severely limits the clinical therapeutic value of molecularly targeted drugs. Growth factors gain a tremendous amount of focus due to the ability to promote drug resistance in non-small-cell lung cancer (NSCLC). However, whether tumor cells themselves can mediate drug resistance by secreting growth factors needs further clarification. Here, we first screened growth factors to identify autocrine epidermal growth factor (EGF) and transforming growth factor alpha (TGF-α) that caused primary resistance to the ALK inhibitor TAE684 in H3122 cells and the c-MET-specific inhibitor SGX-523 in EBC-1 cells. Next, we discovered increased autocrine production of EGF and TGF-α in established acquired resistant H3122/TR and EBC-1/SR cells. Importantly, overexpression of EGF and TGF-α in two NSCLC cell lines produced resistance to TAE684 and SGX-523. Clinically, NSCLC patients with high expression of EGF and TGF-α developed primary resistance to crizotinib. Mechanistically, autocrine EGF and TGF-α activated EGFR signaling pathways to survive targeted c-Met and ALK inhibition. Furthermore, combined treatment with gefitinib circumvented EGF- and TGF-α-mediated primary and acquired resistance to TAE684/SGX-523. Taken together, these results suggested increased autocrine EGF and TGF-α conferred primary and acquired resistance to ALK/c-Met kinase inhibitors in NSCLC.

S3663 Refractory Hypoglycemia Induced by a Gastrointestinal Stromal Tumor Secreting Insulin-Like Growth Factor-2

Introduction: Non-islet cell tumor hypoglycemia (NICTH) is a rare paraneoplastic syndrome that leads to the release of insulin-like growth factor-2 (IGF-2). It is commonly associated with tumors of mesenchymal origin like gastrointestinal stromal tumors (GIST). Case Description/Methods: A 62-year-old male, with a past medical history of recently diagnosed GIST was started on imatinib but stopped taking it one month ago pending surgical evaluation, presents with altered mental status due to severe hypoglycemia. The patient had no prior history of diabetes or adrenal insufficiency. The patient's repetitive finger sticks glucose remained persistently low even after good oral intake and two D50 pushes. Urine toxicology and drug screen for sulfonylureas were negative. Laboratory investigations showed reduced levels of insulin, C-peptide, and insulin-like growth factor-1 (IGF-1), but his IGF-2 was increased. Endocrinology was consulted for refractory hypoglycemia; recommended to start D10 fluids in the setting of resistant low blood glucose and start octreotide and steroids. Insulinoma was unlikely as insulin and C-peptides were low. CT chest/abdomen/pelvis shows grossly unchanged gastric GIST, measuring 25 × 19.6 × 11.4 cm with no evidence of metastatic disease in the abdomen or pelvis (Figure 1A). Esophagogastroduodenoscopy (EGD) demonstrated large, bilobed subepithelial mass measuring 10-15 cm with an area of ulceration within the mass (Figure 1B) followed up with Endoscopic ultrasound (EUS) demonstrating subepithelial lesion was found likely arising from the fundus, lesser curve and body of the stomach, layer of origin could not be determined on due to the large size of the mass (Figure 1C). Oncology was consulted for further management of malignancy; imatinib was resumed and referred for surgical evaluation for tumor removal. Discussion: IGF-II acts as an autocrine growth factor in tumor cells therefore, it is highly likely that IGF-II will be high in case of high tumor bulk and making them at high risk of developing NICTH. In patients diagnosed with GIST with hypoglycemic symptoms, we should consider IGF-II secreting GIST in addition to insulinoma especially in bulky tumors.Figure 1.: A: CT scan abdomen/pelvis with contrast showing large soft tissue density mass inseparable from the lesser curvature of the stomach marked with asterisk. B: EGD findings consistent with a large, bilobed subepithelial mass measuring 10-15 cm with an area of ulceration within the mass (seen best on retroflexion) was found on the lesser curvature of the stomach along the anterior wall of the stomach. C: Endoscopic US findings showed A 43.0 mm × 77.8 mm subepithelial lesion was found likely arising from the fundus, lesser curve and body of the stomach s/p FNB × 4. The lesion was hypoechoic and had some cystic spaces within it in some areas. Sonographically, the lesion appeared to originate from the stomach, but the wall layers could not be determined due to the large size of the mass.

Progranulin is essential for bone homeostasis and immunology.

Intercellular communication or crosstalk between immune and skeletal cells is considered a crucial element in bone homeostasis modulation. Progranulin (PGRN) is an autocrine growth factor that is structured as beads-on-a-string and participates in multiple pathophysiological processes, including atherosclerosis, arthritis, neurodegenerative pathologies, cancer, and wound repair. PGRN functions as a competitor that binds to tumor necrosis factor receptor 1 (TNFR1), thereby blocking the TNF-α pathway. PGRN is regarded as an agonist of chondrogenesis and osteogenesis, delaying the progression of inflammation through the TNFR2 pathway. The exploitation of PGRN may bring benefits for inflammatory bone diseases and the stabilization of bone homeostasis. The PGRN-modified analog Atsttrin possesses three TNFR-binding fragments and thereby exerts superior therapeutic effects on multiple preclinical animal models compared to PGRN. In this review, we highlight the emerging roles of PGRN in bone formation, as well as in physiological and TNF-α-mediated inflammatory conditions revealed in recent discoveries. We address potential therapies for the treatment of inflammatory bone conditions, such as periodontitis, by the use of PGRN and its derivative Atsttrin.

Autocrine FGF1 signaling promotes glucose uptake in adipocytes

Fibroblast growth factor 1 (FGF1) is an autocrine growth factor released from adipose tissue during over-nutrition or fasting to feeding transition. While local actions underlie the majority of FGF1's anti-diabetic functions, the molecular mechanisms downstream of adipose FGF receptor signaling are unclear. We investigated the effects of FGF1 on glucose uptake and its underlying mechanism in murine 3T3-L1 adipocytes and in ex vivo adipose explants from mice. FGF1 increased glucose uptake in 3T3-L1 adipocytes and epididymal WAT (eWAT) and inguinal WAT (iWAT). Conversely, glucose uptake was reduced in eWAT and iWAT of FGF1 knockout mice. We show that FGF1 acutely increased adipocyte glucose uptake via activation of the insulin-sensitive glucose transporter GLUT4, involving dynamic crosstalk between the MEK1/2 and Akt signaling proteins. Prolonged exposure to FGF1 stimulated adipocyte glucose uptake by MEK1/2-dependent transcription of the basal glucose transporter GLUT1. We have thus identified an alternative pathway to stimulate glucose uptake in adipocytes, independent from insulin, which could open new avenues for treating patients with type 2 diabetes.

Nm23-H1 induces apoptosis in primary effusion lymphoma cells via inhibition of NF-κB signaling through interaction with oncogenic latent protein vFLIP K13 of Kaposi's sarcoma-associated herpes virus.

Primary effusion lymphoma (PEL) is an aggressive form of non-Hodgkin lymphoma of B cells caused by Kaposi's Sarcoma-associated Herpes Virus (KSHV). KSHV encoded latent and lytic antigens promote oncogenic transformation and evade apoptosis through the modulation of various host cellular signaling pathways. Nm23-H1 is a known metastatic suppressor whose expression inversely correlates with the metastatic potential of different cancers. Here, we set out to assess the role of Nm23-H1 in PEL development. Flow cytometry and real-time PCR assays were performed for Nm23-H1 expression analysis. Induction of apoptosis was assessed using Western blotting and flow cytometry-based assays in Nm23-H1 overexpressing cells. Co-immunoprecipitation assays, confocal microscopy and imaging flow cytometry were performed to determine Nm23-H1 and vFLIP K13 protein-protein interaction. A PEL cell-induced xenograft model was established in non-obese diabetic/severely combined immunodeficient (NOD/SCID) mice to validate the effect of Nm23-H1 overexpression. We found that Nm23-H1 expression was significantly downregulated both at transcriptional and protein levels in PEL cell lines and that its overexpression triggered mitochondrial-mediated caspase-dependent apoptosis. We revealed Nm23-H1 interacts with the latent protein vFLIP K13 and that Nm23-H1 overexpression leads to inhibition of vFLIP K13 driven nuclear factor-kappa B (NF-κB) signaling with concurrent inhibition of autocrine and paracrine growth factors and downregulation of latent KSHV antigens without induction of active lytic reactivation. We also confirmed the effects of Nm23-H1 overexpression in a PEL cell-induced xenograft model in NOD/SCID mice. Downregulation of Nm23-H1 expression in KSHV-infected PEL cells and its overexpression trigger apoptosis by impairing vFLIP K13-driven NF-κB signaling, suggesting therapeutic implications of Nm23-H1 for primary effusion lymphomas.

A Proliferation-Inducing Ligand and B-Cell Activating Factor Are Upregulated in Patients with Essential Thrombocythemia.

A proliferation-inducing ligand (APRIL) and B-cell activating factor (BAFF) are cytokines belonging to the tumor necrosis factor family which play an essential role in B-cell maturation, differentiation, and survival. Recent evidence indicates their importance in hematological disorders; however, their function in essential thrombocytosis (ET) pathogenesis remains elusive. Therefore, we aimed to analyze the role of APRIL and BAFF in megakaryocytopoiesis in ET patients. We observed elevated levels of APRIL and BAFF in the plasma of ET patients compared with healthy controls, while no differences were found among patients with different JAK2(V617F) statuses. In addition, APRIL levels were positively associated with the number of platelets and WBC count. In the bone marrow, APRIL but not BAFF levels were higher in ET patients with the JAK2(V617F) mutation; however, JAK2(V617F)-negative patients showed slightly reduced levels of BAFF. In ET patients, we showed that the differentiation of CD34+ progenitor cells towards megakaryocytes induces the expression of both APRIL and BAFF. More importantly, APRIL neutralization significantly reduced platelet production. In conclusion, our data provide evidence that blocking APRIL signaling, which acts as an autocrine growth factor for terminal megakaryocytopoiesis, inhibits platelet production in ET patients, regardless of the status of JAK2(V617F) mutation.

SIGIRR Downregulation and Interleukin-1 Signaling Intrinsic to Renal Cell Carcinoma.

Renal cell carcinoma is highly inflamed, and tumor cells are embedded into a microenvironment enriched with IL1. While inflammatory pathways are well characterized in the immune system, less is known about these same pathways in epithelial cells; it is unclear if and how innate immune signals directly impact on cancer cells, and if we could we manipulate these for therapeutic purposes. To address these questions, we first focused on the inflammatory receptors belonging to the IL1- and Toll-like receptor family including negative regulators in a small cohort of 12 clear cell RCC (ccRCC) patients’ samples as compared to their coupled adjacent normal tissues. Our data demonstrated that renal epithelial cancer cells showed a specific and distinctive pattern of inflammatory receptor expression marked by a consistent downregulation of the inhibitory receptor SIGIRR mRNA. This repression was confirmed at the protein level in both cancer cell lines and primary tissues. When we analyzed in silico data of different kidney cancer histotypes, we identified the clear cell subtype as the one where SIGIRR was mostly downregulated; nonetheless, papillary and chromophobe tumor types also showed low levels as compared to their normal counterpart. RNA-sequencing analysis demonstrated that IL1 stimulation of the ccRCC cell line A498 triggered an intrinsic signature of inflammatory pathway activation characterized by the induction of distinct “pro-tumor” genes including several chemokines, the autocrine growth factor IL6, the atypical co-transcription factor NFKBIZ, and the checkpoint inhibitor PD-L1. When we looked for the macroareas most represented among the differentially expressed genes, additional clusters emerged including pathways involved in cell differentiation, angiogenesis, and wound healing. To note, SIGIRR overexpression in A498 cells dampened IL1 signaling as assessed by a reduced induction of NFKBIZ. Our results suggest that SIGIRR downregulation unleashes IL1 signaling intrinsic to tumor cells and that manipulating this pathway may be beneficial in ccRCC.

Helicobacter pylori-Induced Progranulin Promotes the Progression of the Gastric Epithelial Cell Cycle by Regulating CDK4.

Helicobacter pylori, a group 1 carcinogen, colonizes the stomach and affects the development of stomach diseases. Progranulin (PGRN) is an autocrine growth factor that regulates multiple cellular processes and plays a tumorigenic role in many tissues. Nevertheless, the mechanism of action of PGRN in gastric cancer caused by H. pylori infection remains unclear. Here, we investigated the role of PGRN in cell cycle progression and the cell proliferation induced by H. pylori infection. We found that the increased PGRN was positively associated with CDK4 expression in gastric cancer tissue. PGRN was upregulated by H. pylori infection, thereby promoting cell proliferation, and that enhanced level of proliferation was reduced by PGRN inhibitor. CDK4, a target gene of PGRN, is a cyclin-dependent kinase that binds to cyclin D to promote cell cycle progression, which was upregulated by H. pylori infection. We also showed that knockdown of CDK4 reduced the higher cell cycle progression caused by upregulated PGRN. Moreover, when the PI3K/Akt signaling pathway (which is promoted by PGRN) was blocked, the upregulation of CDK4 mediated by PGRN was reduced. These results reveal the potential mechanism by which PGRN plays a major role through CDK4 in the pathological mechanism of H. pylori infection.

Abstract 2688: Bombesin receptors regulate transactivation of HER4

Abstract Bombesin (BB) is an autocrine growth factor for non-small cell lung cancer (NSCLC) cells. BB stimulates whereas the BB2 receptor (R) antagonist PD176252 inhibits NSCLC growth (Moody et al., Eur. J. Pharmacol; 2003; 474:21). The BB2R regulates the transactivation of the EGFR, HER2 and HER3 (Lee et al., BBAMCR 2020; 1867: 118625). HER4 increases the proliferation of NSCLC cells (Mota et al., Oncotarget 2017; 8: 89284). It is unknown if BB2R stimulation increases tyrosine phosphorylation of HER4 and this was investigated using NSCLC cells. BB or neuregulin (NRG1) addition to NSCLC cells increased the phosphorylation of Tyr1284-HER4. By RT-PCR and western blot, mRNA and protein for BB2R, HER4 and NRG1 was present in NCI-H522 and NCI-H661 NSCLC cells. The addition of BB to NCI-H522 or NCI-H661 cells increased phosphorylation of HER4, ERK and AKT which was blocked by PD176252. By immunoprecipitation, HER4 heterodimerized with HER2 and the EGFR after addition of BB to NSCLC cells. PP2 and N-acetylcysteine impaired the ability of BB to increase P-Tyr1284-HER4 in NSCLC cells, which indicates that SRC and reactive oxygen species are essential. Ibrutinib, a tyrosine kinase inhibitor (Rauf et al., Oncogene 2018; 37: 2237), impaired the ability of BB2Rs to regulate HER4 transactivation. Ibrutinib or PD176252 inhibited the growth of NSCLC cells whereas BB or NRG1 increased NSCLC colony formation. The results indicate that peptide receptors for BB regulate HER4 transactivation and the proliferation of NSCLC cells. Citation Format: Terry W. Moody, Irene Ramos-Alvarez, Samuel A. Mantey, Robert T. Jensen. Bombesin receptors regulate transactivation of HER4 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2688.

Autocrine signaling can explain the emergence of Allee effects in cancer cell populations.

In many human cancers, the rate of cell growth depends crucially on the size of the tumor cell population. Low, zero, or negative growth at low population densities is known as the Allee effect; this effect has been studied extensively in ecology, but so far lacks a good explanation in the cancer setting. Here, we formulate and analyze an individual-based model of cancer, in which cell division rates are increased by the local concentration of an autocrine growth factor produced by the cancer cells themselves. We show, analytically and by simulation, that autocrine signaling suffices to cause both strong and weak Allee effects. Whether low cell densities lead to negative (strong effect) or reduced (weak effect) growth rate depends directly on the ratio of cell death to proliferation, and indirectly on cellular dispersal. Our model is consistent with experimental observations from three patient-derived brain tumor cell lines grown at different densities. We propose that further studying and quantifying population-wide feedback, impacting cell growth, will be central for advancing our understanding of cancer dynamics and treatment, potentially exploiting Allee effects for therapy.

Deletion of STAT3 from Foxd1 cell population protects mice from kidney fibrosis by inhibiting pericytes trans-differentiation and migration.

Signal transduction and activator of transcription 3 (STAT3) is a key transcription factor implicated in the pathogenesis of kidney fibrosis. Although Stat3 deletion in tubular epithelial cells is known to protect mice from fibrosis, vFoxd1 cells remains unclear. Using Foxd1-mediated Stat3 knockout mice, CRISPR, and inhibitors of STAT3, we investigate its function. STAT3 is phosphorylated in tubular epithelial cells in acute kidney injury, whereas it is expanded to interstitial cells in fibrosis in mice and humans. Foxd1-mediated deletion of Stat3 protects mice from folic-acid- and aristolochic-acid-induced kidney fibrosis. Mechanistically, STAT3 upregulates the inflammation and differentiates pericytes into myofibroblasts. STAT3 activation increases migration and profibrotic signaling in genome-edited, pericyte-like cells. Conversely, blocking Stat3 inhibits detachment, migration, and profibrotic signaling. Furthermore, STAT3 binds to the Collagen1a1 promoter in mouse kidneys and cells. Together, our study identifies a previously unknown function of STAT3 that promotes kidney fibrosis and has therapeutic value in fibrosis.