Growth differentiation factor 15 is a promising diagnostic and prognostic biomarker in colorectal cancer

Updates in Cancer Cachexia: Clinical Management and Pharmacologic Interventions

Despite a better understanding of the mechanisms causing cancer cachexia (CC) and development of promising pharmacologic and supportive care interventions, CC persists as an underdiagnosed and undertreated condition. CC contributes to fatigue, poor quality of life, functional impairment, increases treatment related toxicity, and reduces survival. The core elements of CC such as weight loss and poor appetite should be identified early. Currently, addressing contributing conditions (hypothyroidism, hypogonadism, and adrenal insufficiency), managing nutrition impact symptoms leading to decreased oral intake (nausea, constipation, dysgeusia, stomatitis, mucositis, pain, fatigue, depressed mood, or anxiety), and the addition of pharmacologic agents when appropriate (progesterone analog, corticosteroids, and olanzapine) is recommended. In Japan, the clinical practice has changed based on the availability of Anamorelin, a ghrelin receptor agonist that improved lean body mass, weight, and appetite-related quality of life (QoL) compared to a placebo, in phase III trials. Other promising therapeutic agents currently in trials include Espindolol, a non-selective β blocker and a monoclonal antibody to GDF-15. In the future, a single therapeutic agent or perhaps multiple medications targeting the various mechanisms of CC may prove to be an effective strategy. Ideally, these medications should be incorporated into a multimodal interdisciplinary approach that includes exercise and nutrition.

Growth differentiation factor-15 serum concentrations reflect disease severity and anemia in patients with inflammatory bowel disease

BACKGROUND

Population of patients with inflammatory bowel disease (IBD) is burdened by various extraintestinal manifestations which substantially contribute to greater morbidity and mortality. Growth-differentiation factor-15 (GDF-15) is often over-expressed under stress conditions, such as inflammation, malignancies, heart failure, myocardial ischemia, and many others.

AIM

To explore the association between GDF-15 and IBD as serum concentrations of GDF-15 were shown to be an independent predictor of poor outcomes in multiple diseases. An additional aim was to determine possible associations between GDF-15 and multiple clinical, anthropometric and laboratory parameters in patients with IBD.

METHODS

This cross-sectional study included 90 adult patients diagnosed with IBD, encompassing both Crohn's disease (CD) and ulcerative colitis (UC), and 67 healthy age- and sex-matched controls. All patients underwent an extensive workup, including colonoscopy with subsequent histopathological analysis. Disease activity was assessed by two independent gastroenterology consultants specialized in IBD, employing well-established clinical and endoscopic scoring systems. GDF-15 serum concentrations were determined following an overnight fasting, using electrochemiluminescence immunoassay.

RESULTS

In patients with IBD, serum GDF-15 concentrations were significantly higher in comparison to the healthy controls [800 (512-1154) pg/mL vs 412 (407-424) pg/mL, P < 0.001], whereas no difference in GDF-15 was found between patients with CD and UC [807 (554-1451) pg/mL vs 790 (509-956) pg/mL, P = 0.324]. Moreover, multiple linear regression analysis showed that GDF-15 levels predict CD and UC severity independent of age, sex, and C-reactive protein levels (P = 0.016 and P = 0.049, respectively). Finally, an association between GDF-15 and indices of anemia was established. Specifically, negative correlations were found between GDF-15 and serum iron levels (r = -0.248, P = 0.021), as well as GDF-15 and hemoglobin (r = -0.351, P = 0.021). Accordingly, in comparison to IBD patients with normal hemoglobin levels, GDF-15 serum levels were higher in patients with anemia (1256 (502-2100) pg/mL vs 444 (412-795) pg/mL, P < 0.001).

CONCLUSION

For the first time, we demonstrated that serum concentrations of GDF-15 are elevated in patients with IBD in comparison to healthy controls, and the results imply that GDF-15 might be involved in IBD pathophysiology. Yet, it remains elusive whether GDF-15 could serve as a prognostic indicator in these patients.

The contribution of the nervous system in the cancer progression

Cancer progression is driven by genetic mutations, environmental factors, and intricate interactions within the tumor microenvironment (TME). The TME comprises of diverse cell types, such as cancer cells, immune cells, stromal cells, and neuronal cells. These cells mutually influence each other through various factors, including cytokines, vascular perfusion, and matrix stiffness. In the initial or developmental stage of cancer, neurotrophic factors such as nerve growth factor, brain-derived neurotrophic factor, and glial cell line-derived neurotrophic factor are associated with poor prognosis of various cancers by communicating with cancer cells, immune cells, and peripheral nerves within the TME. Over the past decade, research has been conducted to prevent cancer growth by controlling the activation of neurotrophic factors within tumors, exhibiting a novel attemt in cancer treatment with promising results. More recently, research focusing on controlling cancer growth through regulation of the autonomic nervous system, including the sympathetic and parasympathetic nervous systems, has gained significant attention. Sympathetic signaling predominantly promotes tumor progression, while the role of parasympathetic signaling varies among different cancer types. Neurotransmitters released from these signalings can directly or indirectly affect tumor cells or immune cells within the TME. Additionally, sensory nerve significantly promotes cancer progression. In the advanced stage of cancer, cancer-associated cachexia occurs, characterized by tissue wasting and reduced quality of life. This process involves the pathways via brainstem growth and differentiation factor 15-glial cell line-derived neurotrophic factor receptor alpha-like signaling and hypothalamic proopiomelanocortin neurons. Our review highlights the critical role of neurotrophic factors as well as central nervous system on the progression of cancer, offering promising avenues for targeted therapeutic strategies. [BMB Reports 2024; 57(4): 167-175].

Growth differentiation factor-15 and prediction of cancer-associated thrombosis and mortality: a prospective cohort study

BACKGROUND

Patients with cancer are at increased risk of venous thromboembolism (VTE) and arterial thromboembolic/thrombotic events (ATEs). Growth differentiation factor-15 (GDF-15) improves cardiovascular risk assessment, but its predictive utility in patients with cancer remains undefined.

OBJECTIVES

To investigate the association of GDF-15 with the risks of VTE, ATE, and mortality in patients with cancer and its predictive utility alongside established models.

METHODS

The Vienna Cancer and Thrombosis Study (CATS)-a prospective, observational cohort study of patients with newly diagnosed or recurrent cancer-which was followed for 2 years, served as the study framework. Serum GDF-15 levels at study inclusion were measured, and any association with VTE, ATE, and death was determined using competing risk (VTE/ATE) or Cox regression (death) modeling. The added value of GDF-15 to established VTE risk prediction models was assessed using the Khorana and Vienna CATScore.

RESULTS

Among 1531 included patients with cancer (median age, 62 years; 53% men), median GDF-15 levels were 1004 ng/L (IQR, 654-1750). Increasing levels of GDF-15 were associated with the increased risks of VTE, ATE, and all-cause death ([subdistribution] hazard ratio per doubling, 1.16 [95% CI, 1.03-1.32], 1.30 [95% CI, 1.11-1.53], and 1.57 [95% CI, 1.46-1.69], respectively). After adjustment for clinically relevant covariates, the association only prevailed for all-cause death (hazard ratio, 1.21; 95% CI, 1.10-1.33) and GDF-15 did not improve the performance of the Khorana or Vienna CATScore.

CONCLUSION

GDF-15 is strongly associated with survival in patients with cancer, independent of the established risk factors. While an association with ATE and VTE was identified in univariable analysis, GDF-15 was not independently associated with these outcomes and failed to improve established VTE prediction models.

Creation of a Peptide Antagonist of the GFRAL-RET Receptor Complex for the Treatment of GDF15-Induced Malaise

Growth differentiation factor 15 (GDF15) is a contributor to nausea, emesis, and anorexia following chemotherapy via binding to the GFRAL-RET receptor complex expressed in hindbrain neurons. Therefore, GDF15-mediated GFRAL-RET signaling is a promising target for improving treatment outcomes for chemotherapy patients. We developed peptide-based antagonists of GFRAL that block GDF15-mediated RET recruitment. Our initial library screen led to five novel peptides. Surface plasmon resonance and flow cytometric analyses of the most efficacious of this group, termed GRASP, revealed its capacity to bind to GFRAL. In vivo studies in rats revealed that GRASP could attenuate GDF15-induced nausea and anorexia resulting from cisplatin. Combined with Ondansetron, GRASP led to an even greater attenuation of the anorectic effects of cisplatin compared to either agent alone. Our results highlight the beneficial effects of GRASP as an agent to combat chemotherapy-induced malaise. GRASP may also be effective in other conditions associated with elevated levels of GDF15.

GDF15 negatively regulates chemosensitivity via TGFBR2-AKT pathway-dependent metabolism in esophageal squamous cell carcinoma

Treating patients with esophageal squamous cell carcinoma (ESCC) is challenging due to the high chemoresistance. Growth differentiation factor 15 (GDF15) is crucial in the development of various types of tumors and negatively related to the prognosis of ESCC patients according to our previous research. In this study, the link between GDF15 and chemotherapy resistance in ESCC was further explored. The relationship between GDF15 and the chemotherapy response was investigated through in vitro and in vivo studies. ESCC patients with high levels of GDF15 expression showed an inferior chemotherapeutic response. GDF15 improved the tolerance of ESCC cell lines to low-dose cisplatin by regulating AKT phosphorylation via TGFBR2. Through an in vivo study, we further validated that the anti-GDF15 antibody improved the tumor inhibition effect of cisplatin. Metabolomics showed that GDF15 could alter cellular metabolism and enhance the expression of UGT1A. AKT and TGFBR2 inhibition resulted in the reversal of the GDF15-induced expression of UGT1A, indicating that TGFBR2-AKT pathway-dependent metabolic pathways were involved in the resistance of ESCC cells to cisplatin. The present investigation suggests that a high level of GDF15 expression leads to ESCC chemoresistance and that GDF15 can be targeted during chemotherapy, resulting in beneficial therapeutic outcomes.

Growth differentiation factor 15 as a novel diagnostic and therapeutic marker for autoimmune hepatitis

Growth differentiation factor 15 (GDF15) has been reported to be associated with fibrosis and cancer in liver disease. Diagnosis of autoimmune hepatitis (AIH) is often difficult because of the lack of specific markers. We investigated whether GDF15 is useful for diagnosing AIH and determined its therapeutic effects. We enrolled 171 Japanese patients as follows: AIH (n = 45), hepatitis B (HB) (n = 17), hepatitis C (HC) (n = 15), primary biliary cholangitis (PBC) (n = 20), and 74 healthy controls. Serum GDF15 levels were measured, and immunohistological analyses of GDF15 were performed using liver tissue of AIH patients. (1) GDF15 levels (pg/ml) were higher in AIH (1994.3 ± 1258.0) and HC (1568.0 ± 822.3) than in HB (953.2 ± 871.4), PBC (643.9 ± 247.0), and controls (475.3 ± 145.3) (p < 0.0001), as well as in cirrhosis patients (n = 31) than in non-cirrhosis patients (n = 66) (1926.6 ± 1026.0 vs. 1249.1 ± 1124.1, p < 0.0001). In non-cirrhosis patients, GDF15 levels were higher in AIH (1914.0 ± 1327.2) than in HC (955.7 ± 502.7), HB (519.3 ± 197.5), and PBC (643.9 ± 247.0) (p < 0.0001). (2) GDF15 was positively correlated with M2BPGi (r = 0.7728), total bilirubin (r = 0.6231), and PT-INR (r = 0.6332). (3) GDF15 levels could be used to distinguish AIH from other liver diseases in non-cirrhosis patients, with an area under the curve of 0.9373 (sensitivity 93.6%, specificity 79.3%, cut-off value 931.3). (4) GDF15 in AIH decreased after treatment. (5) Immunohistological analyses in AIH liver tissues revealed that GDF15 was strongly expressed in inflammatory cells, hepatic cytoplasm, and sinusoidal endothelial cells, but decreased after treatment. GDF15 is a novel diagnostic marker for AIH and is also expected to be a therapeutic marker for AIH.Clinical Trials Registration: The study protocol was approved by the institutional review board of Kurume University (Approval No.: 19049).

Clinical Relevance of Myopenia and Myosteatosis in Colorectal Cancer

Sarcopenia was initially described as a decrease in muscle mass associated with aging and subsequently also as a consequence of underlying disease, including advanced malignancy. Accumulating evidence shows that sarcopenia has clinically significant effects in patients with malignancy, including an increased risk of adverse events associated with medical treatment, postoperative complications, and a poor survival outcome. Colorectal cancer (CRC) is one of the most common cancers worldwide, and several lines of evidence suggest that preoperative sarcopenia negatively impacts various outcomes in patients with CRC. In this review, we summarize the current evidence in this field and the clinical relevance of sarcopenia in patients with CRC from three standpoints, namely, the adverse effects of medical treatment, postoperative infectious complications, and oncological outcomes.

Multi-Omics Reveal the Immunological Role and the Theragnostic Value of miR-216a/GDF15 Axis in Human Colon Adenocarcinoma

Colon adenocarcinoma (COAD) is the most common type of gastrointestinal cancer and is still the third leading cause of cancer-related mortality worldwide. Accurate screening tools for early diagnosis and prediction of prognosis and precision treatment strategies are urgently required to accommodate the unmet medical needs of COAD management. We herein aimed to explore the significance of the microRNA (miR)-216a/growth differentiation factor 15 (GDF15) axis in terms of clinical value, tumor immunity, and potential mechanisms in COAD by using multi-omic analysis. The gene expression levels of miR-216a and GDF15 showed an increase in the COAD group compared to those of the normal group. The expression of miR-216a presented a negative correlation with GDF15 in COAD tumor tissue. The use of an in vitro luciferase reporter assay and bioinformatic prediction revealed that miR-216a-3p acted toward translational inhibition on GDF15 by targeting its 3′untranslated region (UTR) site. High miR-216a expression was associated with decreased overall survival (OS), while the high expression of GDF15 was associated with increased OS. Enriched type 1 T-helper (Th1), enriched regulatory T (Treg), enriched eosinophils, and decreased nature killer T-cells (NKTs) in COAD tumor tissue may play counteracting factors on the tumor-regulatory effects of miR-216a and GDF15. In addition, high GDF15 expression had associations with suppressed immunoinhibitory genes and negative correlations with the infiltration of macrophages and endothelial cells. The enrichment analysis revealed that GDF15 and its co-expression network may be implicated in mitochondrial organization, apoptosis signaling, and endoplasmic reticulum (ER) stress response. The Genomics of Drug Sensitivity in Cancer (GDSC) and Cancer Therapeutics Response Portal (CTRP) analysis identified that Gemcitabine acted as a precision treatment for COAD when GDF15 expression was low. This study supports the miR-216a/GDF15 axis as a diagnostic/prognostic panel for COAD, identifies Th1, Treg, eosinophils, and NKTs as counteracting factors, indicates potential relationships underlying immunomodulation, mitochondrial organization, apoptotic signaling, and ER stress and unveil Gemcitabine as a potential drug for the development of treatment strategy when combined with targeting GDF15.

Mitochondrial dysfunction, UPRmt signaling, and targeted therapy in metastasis tumor

In modern research, mitochondria are considered a more crucial energy plant in cells. Mitochondrial dysfunction, including mitochondrial DNA (mtDNA) mutation and denatured protein accumulation, is a common feature of tumors. The dysfunctional mitochondria reprogram molecular metabolism and allow tumor cells to proliferate in the hostile microenvironment. One of the crucial signaling pathways of the mitochondrial dysfunction activation in the tumor cells is the retrograde signaling of mitochondria-nucleus interaction, mitochondrial unfolded protein response (UPR^mt), which is initiated by accumulation of denatured protein and excess ROS production. In the process of UPR^mt, various components are activitated to enhance the mitochondria-nucleus retrograde signaling to promote carcinoma progression, including hypoxia-inducible factor (HIF), activating transcription factor ATF-4, ATF-5, CHOP, AKT, AMPK. The retrograde signaling molecules of overexpression ATF-5, SIRT3, CREB, SOD1, SOD2, early growth response protein 1 (EGR1), ATF2, CCAAT/enhancer-binding protein-d, and CHOP also involved in the process. Targeted blockage of the UPR^mt pathway could obviously inhibit tumor proliferation and metastasis. This review indicates the UPR^mt pathways and its crucial role in targeted therapy of metastasis tumors.

GDF-15 Level Correlates with CMKLR1 and VEGF-A in Tumor-free Margin in Colorectal Cancer

Colorectal cancer (CRC) is the third most frequently diagnosed cancer worldwide, responsible for over 880 000 deaths each year. Growth/differentiation factor 15 (GDF-15) is reported to be a promising diagnostic and prognostic factor in CRC. It induces pleiotropic effects in tumor cells: proliferation, stemness, invasion and metastasis. Some studies indicate that GDF-15 may stimulate angiogenesis in malignant neoplasms. However, it has not been investigated in CRC yet. The aim of our study was to determine the level of GDF-15 and the concentrations of hypoxia-inducible factor-1α (HIF-1α), VEGF-A and chemokine-like receptor 1 (CMKLR1) in tumor and margin specimens of CRC in relation to histological grade and TNM staging. The study comprised 33 samples of tumor and margin tissues obtained from CRC patients. To assess the concentration of GDF-15, HIF-1α, VEGF-A and CMKLR1, commercially available enzyme-linked immunosorbent assay (ELISA) kits were used. We found significantly increased levels of GDF-15 and CMKLR1 in tumor tissue compared to margin tissue and higher concentrations of HIF-1α and VEGF-A in margin tissue than in tumor tissue. The levels of GDF-15 and HIF-1α were significantly correlated with VEGF-A and CMKLR1 in margin tissue. In CRC, the increased level of GDF-15 might stimulate angiogenesis through upregulation of HIF-1α, VEGF A and CMKLR1 expression. Our study is the first one to reveal the correlation between the levels of GDF-15 and CMKLR1 in CRC. The elevated levels of HIF-1α and VEGF-A in tumor-free margin tissues suggest that noncancer cells in the tumor microenvironment are an important source of proangiogenic factors.

Lipopolysaccharide-regulated secretion of soluble and vesicle-based proteins from a panel of colorectal cancer cell lines

PURPOSE

To mimic the perioperative microenvironment where bacterial products get in contact with colorectal cancer (CRC) cells and study its impact on protein release, we exposed six CRC cell lines to lipopolysaccharide (LPS) and investigated the effect on the secretome using in-depth mass spectrometry-based proteomics.

EXPERIMENTAL DESIGN

Cancer cell secretome was harvested in bio-duplicate after LPS treatment, and separated in EV and soluble secretome (SS) fractions. Gel-fractionated proteins were analysed by label-free nano-liquid chromatography coupled to tandem mass spectrometry. NF-κB activation, triggered upon LPS treatment, was evaluated.

RESULTS

We report a CRC secretome dataset of 5601 proteins. Comparison of all LPS-treated cells with controls revealed 37 proteins with altered abundance in the SS, including RPS25; and 13 in EVs, including HMGB1. Comparing controls and LPS-treated samples per cell line, revealed 564 significant differential proteins with fold-change >3. The LPS-induced release of RPS25 was validated by western blot.

CONCLUSIONS AND CLINICAL RELEVANCE

Bacterial endotoxin has minor impact on the global CRC cell line secretome, yet it may alter protein release in a cell line-specific manner. This modulation might play a role in orchestrating the development of a permissive environment for CRC liver metastasis, especially through EV-communication.

Assessing the Associations of Growth Differentiation Factor 15 with Rheumatic Diseases Using Genetic Data

Objective

To investigate the potential causal associations of circulating levels of growth differentiation factor 15 (GDF-15) with the risk of systemic lupus erythematosus (SLE), rheumatoid arthritis (RA) and inflammatory bowel disease (IBD) using a Mendelian randomization (MR) design.

Methods

A genome-wide association study (GWAS) of GDF-15 among 5,440 individuals of European ancestry was used to identify genetic instruments. Summary statistics of SLE, RA and IBD were obtained from publicly available GWASs. We conducted an MR study using the inverse-variance weighted (IVW) method, supplemented with simple-median and weighted-median methods. Cochran Q test and MR-Egger regression were used to detect potential heterogeneity and directional pleiotropy. Odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated.

Results

We found that genetically predicted high circulating GDF-15 levels were associated with a decreased risk of SLE (OR 0.80, 95% CI 0.68–0.92 by IVW), with similar results in sensitivity analyses. In replication analysis using summary data from another SLE GWAS, the results were consistent (OR 0.82, 95% CI 0.71–0.93 by IVW). Moreover, no evidence of heterogeneity or pleiotropy was detected. However, genetically determined circulating levels of GDF-15 were not associated with risk of RA or IBD in the primary analysis and subsequent sensitivity analyses.

Conclusions

Our study suggested an inverse association between circulating GDF-15 levels and risk of SLE, and further studies are warranted to elucidate the underlying biological mechanisms. There was limited evidence supporting a causal association of circulating GDF-15 levels with risk of RA and IBD.

Prognostic Impact of Serum Growth Differentiation Factor 15 Level in Acute Myeloid Leukemia Patients

Growth differentiation factor 15 (GDF15) plays an important role in cancer pathophysiology and prognosis. However, limited studies analyzed its level and prognostic value in acute myeloid leukemia (AML) patients. This study included 56 adult AML patients. Serum GDF15 level was measured at diagnosis in all patients by enzyme-linked immunosorbent assay. Remission and survival statuses were assessed at 90 days following treatment. GDF15 level was significantly higher in patients than in controls (P < 0.001). GDF15 level correlated positively with age (P < 0.001), hemoglobin level (P = 0.027), and platelet count (P = 0.024). High GDF15 above the median level was associated with inferior OS (P = 0.044) together with high platelet count (P = 0.006) and high bone marrow blast percent (P = 0.038). There was no statistically significant difference between patients with GDF15 above and below the median level regarding DFS (P = 0.881). On multivariate analysis for OS, GDF15 level was an independent risk factor (P = 0.047). In conclusion, serum GDF15 level is significantly elevated in AML patients and high GDF15 level is associated with inferior OS.

Antibody-mediated inhibition of GDF15-GFRAL activity reverses cancer cachexia in mice

Cancer cachexia is a highly prevalent condition associated with poor quality of life and reduced survival¹. Tumor-induced perturbations in the endocrine, immune and nervous systems drive anorexia and catabolic changes in adipose tissue and skeletal muscle, hallmarks of cancer cachexia^2-4. However, the molecular mechanisms driving cachexia remain poorly defined, and there are currently no approved drugs for the condition. Elevation in circulating growth differentiation factor 15 (GDF15) correlates with cachexia and reduced survival in patients with cancer^5-8, and a GDNF family receptor alpha like (GFRAL)-Ret proto-oncogene (RET) signaling complex in brainstem neurons that mediates GDF15-induced weight loss in mice has recently been described^9-12. Here we report a therapeutic antagonistic monoclonal antibody, 3P10, that targets GFRAL and inhibits RET signaling by preventing the GDF15-driven interaction of RET with GFRAL on the cell surface. Treatment with 3P10 reverses excessive lipid oxidation in tumor-bearing mice and prevents cancer cachexia, even under calorie-restricted conditions. Mechanistically, activation of the GFRAL-RET pathway induces expression of genes involved in lipid metabolism in adipose tissues, and both peripheral chemical sympathectomy and loss of adipose triglyceride lipase protect mice from GDF15-induced weight loss. These data uncover a peripheral sympathetic axis by which GDF15 elicits a lipolytic response in adipose tissue independently of anorexia, leading to reduced adipose and muscle mass and function in tumor-bearing mice.

Growth/Differentiation Factor-15 (GDF-15): From Biomarker to Novel Targetable Immune Checkpoint

Growth/differentiation factor-15 (GDF-15), also named macrophage inhibitory cytokine-1, is a divergent member of the transforming growth factor β superfamily. While physiological expression is barely detectable in most somatic tissues in humans, GDF-15 is abundant in placenta. Elsewhere, GDF-15 is often induced under stress conditions, seemingly to maintain cell and tissue homeostasis; however, a moderate increase in GDF-15 blood levels is observed with age. Highly elevated GDF-15 levels are mostly linked to pathological conditions including inflammation, myocardial ischemia, and notably cancer. GDF-15 has thus been widely explored as a biomarker for disease prognosis. Mechanistically, induction of anorexia via the brainstem-restricted GDF-15 receptor GFRAL (glial cell-derived neurotrophic factor [GDNF] family receptor α-like) is well-documented. GDF-15 and GFRAL have thus become attractive targets for metabolic intervention. Still, several GDF-15 mediated effects (including its physiological role in pregnancy) are difficult to explain via the described pathway. Hence, there is a clear need to better understand non-metabolic effects of GDF-15. With particular emphasis on its immunomodulatory potential this review discusses the roles of GDF-15 in pregnancy and in pathological conditions including myocardial infarction, autoimmune disease, and specifically cancer. Importantly, the strong predictive value of GDF-15 as biomarker may plausibly be linked to its immune-regulatory function. The described associations and mechanistic data support the hypothesis that GDF-15 acts as immune checkpoint and is thus an emerging target for cancer immunotherapy.

GDF-15 in solid vs non-solid treatment-naïve malignancies

AIM

GDF-15 is an established cardiovascular risk marker but is equally implicated in tumour biology. Elevated levels of GDF-15 have indeed been observed in distinct tumour entities. This study aimed to explore the relation of GDF-15 to other cardiac biomarkers and the general association of GDF-15 on prognosis in an unselected cohort of treatment-naïve cancer patients.

METHODS

We prospectively enrolled 555 consecutive patients at time of diagnosis of malignant disease prior receiving anticancer therapy. Plasma GDF-15 concentrations were determined alongside other cardiac and routine laboratory markers. All-cause mortality was defined as primary endpoint.

RESULTS

GDF-15 levels were 338 ng/L (IQR:205-534) for the total cohort, and values were comparable for different tumour entities except breast cancer. Metastatic disease was characterized by higher plasma GDF-15 [435 ng/L (IQR:279-614) vs 266 ng/L (IQR:175-427), P < .001]. GDF-15 correlated positively with inflammatory status reflected by CRP, SAA and IL-6 [r = .31, P < .001, r = .23, P < .001 and r = .14, P = .002] and cardiac biomarkers as NT-proBNP, hsTnT, MR-proADM and CT-proET-1 [r = .46; r = .46; r = .59 and r = .50; P < .001 for all]. GDF-15 was significantly associated with all-cause mortality after multivariate adjustment [adj.HR for ln(GDF-15) 1.78, 95%CI:1.47-2.16, P < .001]. There was a significant interaction between solid and haematological malignancies with loss of association of GDF-15 with outcome in myelodysplastic and myeloproliferative disease.

CONCLUSIONS

Elevated plasma GDF-15 is associated with progressing disease severity and poor prognosis in solid tumours of treatment-naïve cancer patients. GDF-15 increase is accompanied by worsening systemic inflammation and a subclinical functional impairment of different organs including the heart. GDF-15 represents a promising target for our pathophysiologic understanding in cardio-oncology linking conditions of both cardiac and neoplastic disease.

The impact of GDF-15, a biomarker for metformin, on the risk of coronary artery disease, breast and colorectal cancer, and type 2 diabetes and metabolic traits: a Mendelian randomisation study

AIMS/HYPOTHESIS

Growth differentiation factor 15 (GDF-15), a suggested biomarker for metformin use, may explain the potential cardioprotective and anti-cancer properties of metformin. We conducted a Mendelian randomisation study to examine the role of GDF-15 in risk of coronary artery disease (CAD) and breast and colorectal cancer. Secondary analyses included examination of the association of GDF-15 with type 2 diabetes, glycaemic traits, BP, lipids and BMI.

METHODS

We obtained SNPs strongly (p value <5 × 10^-8) predicting GDF-15 from a genome-wide association study (GWAS) (n = 5440) and applied them to genetic studies of CAD (CARDIoGRAMplusC4D 1000 Genomes-based GWAS [n = 184,305]), type 2 diabetes (DIAGRAM [DIAbetes Genetics Replication And Meta-analysis; n = 898,130]), glycaemic traits (MAGIC [the Meta-Analyses of Glucose and Insulin-related traits Consortium; HbA_1c: n = 123,665; fasting glucose: n = 46,186]), BP, breast cancer and colorectal cancer (UK Biobank [n ≤ 401,447]), lipids (GLGC [Global Lipids Genetic Consortium; n ≤ 92,820]) and adiposity (GIANT [Genetic Investigation of ANthropometric Traits Consortium; n = 681,275]). Causal estimates were obtained using inverse variance weighting, taking into account correlations between SNPs. Sensitivity analyses included focusing on the lead SNP (rs888663) and validation for CAD in the UK Biobank and for breast cancer in the Breast Cancer Association Consortium.

RESULTS

Using 5 SNPs, increased GDF-15 was associated with lower CAD (OR 0.93 per SD increase, 95% CI 0.87, 0.99) and breast cancer (OR 0.89 per SD increase, 95% CI 0.82, 0.96), with similar results from lead SNP analysis. However, the associations with CAD (OR 0.99 per SD increase, 95% CI 0.93, 1.04) and breast cancer (OR 0.97 per SD increase, 95% CI 0.94, 1.01) in the validation studies were not as apparent. GDF-15 was not associated with type 2 diabetes, glycaemic traits, CAD risk factors or colorectal cancer.

CONCLUSIONS/INTERPRETATION

There is no convincing evidence that GDF-15 reduces risk of CAD or breast or colorectal cancer. Whether the observed inverse association of metformin use with cancer risk is via other unexplored mechanistic pathways warrants further investigation.

Growth differentiation factor-15 predicts poor survival after cardiac arrest

BACKGROUND

Early prognostication in post-cardiac arrest (CA) patients remains challenging and biomarkers have evolved as helpful tools in risk assessment. The stress-response cytokine growth differentiation factor-15 (GDF-15) is dramatically up-regulated during various kinds of tissue injury and predicts outcome in many pathological conditions. We aimed to assess the predictive value of circulating GDF-15 in post-CA patients.

METHODS

This prospective observational study included 128 consecutive patients (median age 60.3 years, 75.8% male) with return of spontaneous circulation after in- or out-of-hospital CA who were treated at a tertiary university hospital. GDF-15 serum levels were determined at admission.

RESULTS

A total of 52 patients (40.6%) died during the 6-month follow-up. Median GDF-15 levels were significantly lower in survivors (1601 ng/L (interquartile range: 1114-2983 ng/L) than in non-survivors (3172 ng/L (1927-8340 ng/L); p < 0.001). GDF-15 levels were also significantly lower in patients with favourable neurological 6-month outcome (cerebral performance category (CPC) 1-2) than in those with poor neurological outcome (CPC 3-5; p < 0.001). GDF-15 significantly predicted 6-month mortality in univariate Cox regression analysis (hazard ratio (HR) per 1-standard deviation increase 1.76 [95% confidence interval (CI) 1.35-2.31; p < 0.001] and remained significant after multivariable adjustment (HR 1.57 [95% CI 1.19-2.07; p = 0.001]). Subgroup analysis revealed that the association between GDF-15 and 6-month outcome was present both in patients with in- and out-of-hospital CA.

CONCLUSIONS

GDF-15 predicts poor survival and neurological outcome in post-CA patients. GDF-15 may reflect the extent of hypoxic injury to the brain and other organs and might help to improve early risk stratification after CA.

Growth differentiation factor 15 and its role in carcinogenesis: an update

Growth differentiation factor-15 (GDF-15) is a novel cytokine secreted by a variety of cells like macrophages, adipocytes, normally expressed in high amounts by placenta. It is also highly expressed in multiple carcinomas like Colon, Breast, Pancreas, Liver, and Ovarian. Several reports on serum GDF-15 as a potential biomarker for diagnosis and prognosis of cancer are hampered by the lack of robust data, with large sample size and critical patient recruitment. However, experimental accounts on cancer tumors, cell lines, and animal models suggest GDF-15's role in cancer progression via endothelial mesenchymal transition, angiogenesis, metastasis, drug resistance and even stemness of various cancers. GDF-15 could be the point of amalgamation for the various hallmarks of cancer and can prove a useful therapeutic target in cancer. The current review was conceptualized with a thought of critically appraising the existing information of GDF-15 in carcinogenesis.

Appraising growth differentiation factor 15 as a promising biomarker in digestive system tumors: a meta-analysis

Background

Previous studies have highlighted cytokine growth differentiation factor 15 (GDF-15) as a potential biomarker for digestive system tumors (DST). This study sought to assess the feasibility of using GDF-15 as a diagnostic and prognostic biomarker in DST.

Methods

Eligible studies from multiple online databases were reviewed. Meta-analyses of diagnostic parameters were carried out using standard statistical methods. Study-specific hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated to estimate the strength of the relationship between GDF-15 levels and clinical prognosis.

Results

We identified 17 eligible studies comprising 3966 patients with DST. The sensitivity, specificity, and area under the curve (AUC) for the discriminative performance of GDF-15 as a diagnostic biomarker were 0.74 (95% CI: 0.68–0.80), 0.83 (95% CI: 0.75–0.89), and 0.84, respectively. Moreover, increased GDF-15 expression levels were markedly associated with unfavorable overall survival (OS) in patients with DST (HR = 2.34, 95% CI: 2.03–2.70, P < 0.001; I² = 0.0%) and colorectal cancer (CRC) (HR = 2.27, 95% CI: 1.96–2.63, P < 0.001; I² = 0.0%). Stratification by cancer type, test matrix, ethnicity, and cut-off setting also illustrated the robustness of the diagnostic value of GDF-15 in DST.

Conclusion

Collectively, our data suggest that GDF-15 expression level may have value as a diagnostic and prognostic biomarker, independent of other, traditional biomarkers.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5385-y) contains supplementary material, which is available to authorized users.

Serum Hepcidin and GDF-15 levels as prognostic markers in urothelial carcinoma of the upper urinary tract and renal cell carcinoma

Background

Cancer is a life-threatening disease that causes every fourth death. It is often hard to determine the time point of progression. Therefore, biomarkers for cancer entities that indicate disease progression or aggressiveness and thereby guide therapeutic decisions are required. Unfortunately, reliable biomarkers are rare. In this study, the potential of serum hepcidin and serum GDF-15 as biomarkers that correlate with patient’s survival in the two entities upper urinary tract urothelial carcinomas (UUTUC) and renal cell carcinoma (RCC) were analyzed.

Methods

In this retrospective study n = 38 patients suffering from UUTUC, n = 94 patients suffering from RCC and n = 21 patients without infections or cancer, all hospitalized at the University Hospital Muenster, were included. Serum samples of patients were retrospectively analyzed. Serum hepcidin and GDF-15 levels were measured and correlated to aggressiveness and progression of the disease as well as patient’s outcome.

Results

For both entities, UUTUC and RCC, serum hepcidin levels as well as serum GDF-15 levels were increased compared to sera of controls. High serum hepcidin and GDF-15 levels were associated with metastases and cancer relapse. Also, in both entities, the overall survival was decreased in patients with increased serum hepcidin and GDF-15 levels. Hence, high serum hepcidin and GDF-15 levels correlated with patient’s outcome.

Conclusion

To conclude, the data of this study show a correlation of high serum hepcidin and GDF-15 levels with aggressiveness and progression of the disease and demonstrate potential prognostic properties of serum hepcidin and GDF-15 levels. The data support the further assessment of serum hepcidin and GDF-15 as prognostic markers in RCC and UUTUC.

Ras-ERK1/2 signaling contributes to the development of colorectal cancer via regulating H3K9ac

BACKGROUNDS/AIMS

Ras is a control switch of ERK1/2 pathway, and hyperactivation of Ras-ERK1/2 signaling appears frequently in human cancers. However, the molecular regulation following by Ras-ERK1/2 activation is still unclear. This work aimed to reveal whether Ras-ERK1/2 promoted the development of colorectal cancer via regulating H3K9ac.

METHODS

A vector for expression of K-Ras mutated at G12 V and T35S was transfected into SW48 cells, and the acetylation of H3K9 was measured by Western blot analysis. MTT assay, colony formation assay, transwell assay, chromatin immunoprecipitation and RT-qPCR were performed to detect whether H3K9ac was contributed to K-Ras-mediated cell growth and migration. Furthermore, whether HDAC2 and PCAF involved in modification of H3K9ac following Ras-ERK1/2 activation were studied.

RESULTS

K-Ras mutated at G12 V and T35S induced a significant activation of ERK1/2 signaling and a significant down-regulation of H3K9ac. Recovering H3K9 acetylation by using a mimicked H3K9ac expression vector attenuated the promoting effects of Ras-ERK1/2 on tumor cells growth and migration. Besides, H3K9ac can be deacetylated by HDAC2 and MDM2-depedent degradation of PCAF.

CONCLUSION

H3K9ac was a specific target for Ras-ERK1/2 signaling pathway. H3K9 acetylation can be modulated by HDAC2 and MDM2-depedent degradation of PCAF. The revealed regulation provides a better understanding of Ras-ERK1/2 signaling in tumorigenesis.

The MIC-1/GDF15-GFRAL Pathway in Energy Homeostasis: Implications for Obesity, Cachexia, and Other Associated Diseases

MIC-1/GDF15 is a stress response cytokine and a distant member of the transforming growth factor beta (TGFb) superfamily, with no close relatives. It acts via a recently identified receptor called glial-derived neurotrophic factor (GDNF) receptor alpha-like (GFRAL), which is a distant orphan member of the GDNF receptor family that signals through the tyrosine kinase receptor Ret. MIC-1/GDF15 expression and serum levels rise in response to many stimuli that initiate cell stress and as part of a wide variety of disease processes, most prominently cancer and cardiovascular disease. The best documented actions of MIC-1/GDF15 are on regulation of energy homeostasis. When MIC-1/GDF15 serum levels are substantially elevated in diseases like cancer, it subverts a physiological pathway of appetite regulation to induce an anorexia/cachexia syndrome initiated by its actions on hindbrain neurons. These effects make it a potential target for the treatment of both obesity and anorexia/cachexia syndromes, disorders lacking any highly effective, readily accessible therapies.

Growth/differentiation factor 15 (GDF-15) as new potential serum marker in patients with metastatic colorectal cancer

BACKGROUND

GDF-15 is a protein belonging to the transforming growth factor beta superfamily that has a role in regulating inflammatory and apoptotic pathways. High level GDF-15 in tumor tissues and plasma correlate with an increased risk of recurrence and reduced overall survival.

OBJECTIVE

The aim of this study was to screen GDF-15 capacity to detecting metastatic CRC and compare it with standard tumor markers CEA and CA19-9.

METHODS

We collected serum samples from 97 patients with metastatic colorectal cancer and 79 samples from healthy controls. Serum levels of GDF-15, CEA and CA19-9 were measured by immunochemically. A Kaplan-Meier curve was applied for analysis of survival rates, and a log-rank was used for univariate analysis.

RESULTS

Serum levels of GDF-15 were significantly higher in patients with colorectal cancer compared to healthy controls (p< 0.001). In addition, serum levels of GDF-15 correlated with extent of liver involvement and patients with higher GDF-15 levels had significantly worse outcome (p< 0.0001).

CONCLUSIONS

Our results show GDF-15 as an effective biomarker in patients with metastatic colorectal cancer with the same sensitivity as CEA. In addition, GDF-15 levels strongly correlate with extension of liver involvement in contrast with CEA.

Distinct response to GDF15 knockdown in pediatric and adult glioblastoma cell lines

INTRODUCTION

Glioblastoma (GBM) is the most common malignant primary brain tumor affecting adults. In pediatric patients, GBM exhibits genetic variations distinct from those identified in the adult GBM phenotype. This tumor exhibits complex genetic changes leading to malignant progression and resistance to standard therapies including radiotherapy and temozolomide treatment. The GDF15 gene codes for a growth factor whose expression is altered in the presence of inflammations and malignancies. GDF15 is associated with a poor prognosis and with radio- and chemoresistance in a variety of tumors. The aim of this study was to compare the response to GDF15 knockdown in adult (U343) and pediatric (KNS42) GBM cell line models.

METHODS

The expression of the GDF15 gene was investigated by qRT-PCR and overexpression was identified in both GBM cell lines. The KNS42 and U343 cell lines were submitted to lentiviral transduction with shRNA of GDF15 and validated at the protein level. To understand the difference between cell lines, RNAseq was performed after GDF15 knockdown.

RESULTS

The data obtained demonstrated that the pathways were differentially expressed in adult GBM and pediatric GBM cell lines. This was confirmed by functional assays perfomed after independent treatments (radiotherapy and TMZ).

CONCLUSION

These results demonstrated that GBM cell lines had distinct responses to GDF15 knockdown, a fact that can be explained by the different molecular profile of pediatric and adult GBM.

Circulating MIC-1/GDF15 is a complementary screening biomarker with CEA and correlates with liver metastasis and poor survival in colorectal cancer

Macrophage inhibitory cytokine 1 (MIC-1/GDF15) has been characterized as a candidate biomarker for colorectal cancer (CRC) recently. However, the role of serum MIC-1 in screening patients with early stage CRC and monitoring therapeutic response have not been well-established, particularly in the combination with CEA for the screening and the prejudgment of occurrence with liver metastasis. In this study, we performed a retrospective blinded evaluation of 987 serum samples from 473 individuals with CRC, 25 with adenomatous polyps, and 489 healthy individuals using ELISA or immunoassay. The sensitivity of serum MIC-1 was 43.8% and 38.5% for CRC diagnosis and early diagnosis, respectively, which were independent of and comparatively higher than for CEA (36.6% and 27.3%) at comparable specificity. Serum MIC-1 after surgery were significantly elevated at the time of tumor recurrence, and notable increase were observed in 100% patients with liver metastasis. Besides the TNM classification and differentiation grade, MIC-1 was an independent prognostic factor contributing to overall survival. We conclude that MIC-1 can act as a candidate complementary biomarker for screening early-stage CRC by combination with CEA, and furthermore, for the first time, identify a promising prognostic indicator for monitoring recurrence with liver metastasis, to support strategies towards personalized therapy.

Growth differentiation factor 15 contributes to marrow adipocyte remodeling in response to the growth of leukemic cells

Background

The adipocyte remodeling, including of the morphological change, might indicate special pathological function. Our previous study found that the morphological remodeling of larger marrow adipocytes into small marrow adipocytes correlates with a poor prognosis for acute myeloid leukemia (AML) patients. However, the mechanisms contributed to the marrow adipocyte remodeling are still poorly understood.

Methods

GDF15 expression was analyzed by RT-qPCR and western blotting assays in the leukemic cells. The enhancing and antibody neutralization tests in vitro were employed to evaluate the effect of GDF15 on the morphology of mature adipocytes. CCK8 test was used to detect the proliferation of leukemic cells after co-cultivation with small marrow adipocytes. Flow cytometry was used to analysis the proportion of cell cycle of leukemic cells. Immunofluorescence staining and linear analysis were applied to verify the GDF15 expression and the relationship between GDF15 and small marrow adipocytes in AML patients.

Results

In this study, we found that leukemic cell lines not only expressed significantly higher growth differentiation factor 15 (GDF15) than the other three cytokines associated with adipocyte differentiation in RNA level but also secreted GDF15 factor. Furthermore, the in vitro experiments demonstrated that GDF15 was involved in the conversion of small marrow adipocytes from larger marrow adipocytes. Correspondingly, the leukemic cells proliferated more rapidly through regulating the cell cycle when co-cultured with GDF15-induced small marrow adipocytes. The immunofluorescence staining on the bone marrow sections of AML patients further exhibited that GDF15 was partly produced by leukemic cells. The positive correlation between the concentration of GDF15 in the marrow aspirates and the number and the volume of small marrow adipocytes might suggest the contribution of GDF15 in AML patients (r = 0.72, r = 0.67).

Conclusions

GDF15 secreted by leukemic cells was involved in the morphological remodeling of marrow adipocytes, which can in turn promote leukemic cell growth, indicating that GDF15 may be a promising treatment target for AML patients.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0738-y) contains supplementary material, which is available to authorized users.

Solid Stress Facilitates Fibroblasts Activation to Promote Pancreatic Cancer Cell Migration

Pancreatic fibroblasts are continuously gaining ground as an important component of tumor microenvironment that dynamically interact with cancer cells to promote tumor progression. In addition, these tumor-infiltrated fibroblasts can acquire an activated phenotype and produce excessive amounts of extracellular matrix creating a highly dense stroma, a situation known as desmoplasia. Desmoplasia, along with the uncontrolled proliferation of cancer cells, leads to the development of compressive forces within the tumor, generating the so-called solid stress. Solid stress is previously shown to affect cancer cell proliferation and migration, however there is no pertinent study taking into account the effects of solid stress on fibroblasts and whether these effects contribute to tumor progression. In this work, we applied a defined compressive stress on pancreatic fibroblasts, similar in magnitude to that experienced by cells in native pancreatic tumors. Our results suggest that solid stress stimulates fibroblasts activation and strongly upregulates Growth Differentiation Factor-15 (GDF15) expression. Moreover, co-culture of compression-induced activated fibroblasts with pancreatic cancer cells significantly promotes cancer cell migration, which is inhibited by shRNA-mediated silencing of GDF15 in fibroblasts. Conclusively, our findings highlight the involvement of biophysical factors, such as solid stress, in tumor progression and malignancy revealing a novel role for GDF15.

An Assessment of Novel Biomarkers in Bone Metastatic Disease Using Multiplex Measurement and Multivariate Analysis

Aim:

Current diagnostics of bone metastatic disease is not satisfactory for early detection or regular process monitoring. The combination of biomarkers and the multiparametric approach was described as effective in other oncology diagnoses. The aim of the study was to improve the difference diagnostics between bone-metastatic disease and solid tumors using mutivariate logistic regression model.

Methods:

We assessed the group of 131 patients with the following diagnoses: prostate cancer, breast cancer, lung cancer, and colorectal cancer. According to the results of scintigraphy, the cohort was divided into 2 groups based on the occurrence of bone metastases. Group 0 was a control group of 75 patients with no signs of bone metastases and group 1 included 56 patients with bone metastases.

Results:

We used stepwise selection multivariate logistic regression for choosing the multimarker formula for calculation of risk score for bone metastases diagnostics. For detection of bone metastasis, it was shown to be most effective measurement of 3 biomarkers: procollagen type 1 N-terminal propeptide, growth differentiation factor-15, and osteonectin and combining with calculation of risk score by designating measured concentrations in mathematical formula: bone risk score = procollagen type 1 N-terminal propeptide × 0.0500 + growth differentiation factor-15 × 1.4179 + osteonectin × 0.00555.

Conclusion:

We identified growth differentiation factor-15 as the best individual marker for bone metastasis diagnostics. The best formula for risk score includes levels of 3 biomarkers—procollagen type 1 N-terminal propeptide, growth differentiation factor-15, and osteonectin. The new score has better performance described by higher area under the curve than individual biomarkers. A further study is necessary to confirm these findings incorporating a larger number of patients.

miR-34a Regulates Expression of the Stathmin-1 Oncoprotein and Prostate Cancer Progression

In aggressive prostate cancers, the oncoprotein STMN1 (also known as stathmin 1 and oncoprotein 18) is often overexpressed. STMN1 is involved in various cellular processes, including cell proliferation, motility, and tumor metastasis. Here, it was found that the expression of STMN1 RNA and protein is elevated in metastatic prostate cancers. Knockdown of STMN1 resulted in reduced proliferation and invasion of cells and tumor growth and metastasis in vivo Furthermore, miR-34a downregulated STMN1 by directly binding to its 3'-UTR. Overexpression of miR-34a in prostate cancer cells reduced proliferation and colony formation, suggesting that it is a tumor suppressor. The transcriptional corepressor C-terminal binding protein 1 (CtBP1) negatively regulated expression of miR-34a. Furthermore, gene expression profiling of STMN1-modulated prostate cancer cells revealed molecular alterations, including elevated expression of growth differentiation factor 15 (GDF15), which is involved in cancer progression and potentially in STMN1-mediated oncogenesis. Thus, in prostate cancer, CtBP1-regulated miR-34a modulates STMN1 expression and is involved in cancer progression through the CtBP1\miR-34a\STMN1\GDF15 axis.Implications: The CtBP1\miR-34a\STMN1\GDF15 axis is a potential therapeutic target for treatment of aggressive prostate cancer. Mol Cancer Res; 16(7); 1125-37. ©2017 AACR.

Genetic and epigenetic markers in colorectal cancer screening: recent advances

INTRODUCTION

Colorectal cancer (CRC) is a heterogenous disease which develops from benign intraepithelial lesions known as adenomas to malignant carcinomas. Acquired alterations in Wnt signaling, TGFβ, MAPK pathway genes and clonal propagation of altered cells are responsible for this transformation. Detection of adenomas or early stage cancer in asymptomatic patients and better prognostic and predictive markers is important for improving the clinical management of CRC. Area covered: In this review, the authors have evaluated the potential of genetic and epigenetic alterations as markers for early detection, prognosis and therapeutic predictive potential in the context of CRC. We have discussed molecular heterogeneity present in CRC and its correlation to prognosis and response to therapy. Expert commentary: Molecular marker based CRC screening methods still fail to gain trust of clinicians. Invasive screening methods, molecular heterogeneity, chemoresistance and low quality test samples are some key challenges which need to be addressed in the present context. New sequencing technologies and integrated omics data analysis of individual or population cohort results in GWAS. MPE studies following a GWAS could be future line of research to establish accurate correlations between CRC and its risk factors. This strategy would identify most reliable biomarkers for CRC screening and management.

GDF15 contributes to radioresistance and cancer stemness of head and neck cancer by regulating cellular reactive oxygen species via a SMAD-associated signaling pathway

Radiotherapy is an integral part for the treatment of head and neck cancer (HNC), while radioresistance is a major cause leads to treatment failure. GDF15, a member of the TGF-β superfamily, is hypothesized to participate in various types of homeostasis. However, the potential role of this molecule in regulation of radiosensitivity remains unclear. In this study, we demonstrated that GDF15 contributed to radioresistance of HNC, as determined by both gain- and lost-of-functional experiments. These results were achieved by the induction of mitochondrial membrane potential and suppression of intracellular reactive oxygen species (ROS). We further showed that GDF15 facilitated the conversion of cancer stemness, as assessed by the promotion of CD44+ and ALDH1+ cell populations and spheroid cell formation. At molecular level, GDF15 conferred to these cellular functions was through phosphorylated SMAD1 proteins to elite downstream signaling molecules. These cellular results were further confirmed in a tumor xenograft mouse study. Taken together, our results demonstrated that GDF15 contributed to radioresistance and cancer stemness by regulating cellular ROS levels via a SMAD-associated signaling pathway. GDF15 may serve as a prediction marker of radioresistance and a therapeutic target for the development of radio-sensitizing agents for the treatment of refractory HNC.