Serine synthesis and catabolism in starved lung cancer and primary bronchial epithelial cells.

Serine and glycine give rise to important building blocks in proliferating cells. Both amino acids are either synthesized de novo or taken up from the extracellular space. In lung cancer, serine synthesis gene expression is variable, yet, expression of the initial enzyme, phosphoglycerate dehydrogenase (PHGDH), was found to be associated with poor prognosis. While the contribution of de novo synthesis to serine pools has been shown to be enhanced by serine starvation, the impact of glucose deprivation, a commonly found condition in solid cancers is poorly understood. Here, we utilized a stable isotopic tracing approach to assess serine and glycine de novo synthesis and uptake in different lung cancer cell lines and normal bronchial epithelial cells in variable serine, glycine, and glucose conditions. Under low glucose supplementation (0.2 mM, 3-5% of normal plasma levels), serine de novo synthesis was maintained or even activated. As previously reported, also gluconeogenesis supplied carbons from glutamine to serine and glycine under these conditions. Unexpectedly, low glucose treatment consistently enhanced serine to glycine conversion, along with an up-regulation of the mitochondrial one-carbon metabolism enzymes, serine hydroxymethyltransferase (SHMT2) and methylenetetrahydrofolate dehydrogenase (MTHFD2). The relative contribution of de novo synthesis greatly increased in low serine/glycine conditions. In bronchial epithelial cells, adaptations occurred in a similar fashion as in cancer cells, but serine synthesis and serine to glycine conversion, as assessed by label enrichments and gene expression levels, were generally lower than in (PHGDH positive) cancer cells. In summary, we found a variable contribution of glucose or non-glucose carbon sources to serine and glycine and a high adaptability of the downstream one-carbon metabolism pathway to variable glucose supply.

Metabolic heterogeneity in cancer.

Cancer cells rewire their metabolism to survive during cancer progression. In this context, tumour metabolic heterogeneity arises and develops in response to diverse environmental factors. This metabolic heterogeneity contributes to cancer aggressiveness and impacts therapeutic opportunities. In recent years, technical advances allowed direct characterisation of metabolic heterogeneity in tumours. In addition to the metabolic heterogeneity observed in primary tumours, metabolic heterogeneity temporally evolves along with tumour progression. In this Review, we summarize the mechanisms of environment-induced metabolic heterogeneity. In addition, we discuss how cancer metabolism and the key metabolites and enzymes temporally and functionally evolve during the metastatic cascade and treatment.

Men don't cry: The supporting role as necessary for women's well-being after termination of pregnancy.

OBJECTIVES: The present study investigated similarities and differences of grief between men and women as part of the parental couple 1 year after termination of pregnancy (TOP) following a diagnosis of fetal anomaly. METHODS: We applied a method triangulation approach. We assessed several aspects of perinatal grief, depressive symptoms, posttraumatic stress, and anxiety as well as health-related quality of life. In addition, we conducted qualitative interviews with the men to explore the fathers' roles in the partnership during pregnancy, the time of the diagnosis, TOP, and afterwards. RESULTS: Women showed a more elevated grief response compared with men. Qualitative data revealed that men in our sample were mainly concerned with their partners' well-being and concentrated on supporting their partners rather than on their own emotions. In addition, the supportive role of the male partner plays a central role in the well-being of women and the man's coping with the situation. CONCLUSION: In clinical work, but also when developing new questionnaires, the specific role of the male partners needs to be considered more thoroughly. Particular attention should be paid to identify the men who find it difficult to assume the supporting role.

Termination of pregnancy for fetal malformation: A traumatic event? A qualitative analysis of women's perception.

Objective: To investigate women's experience of termination of pregnancy (TOP) for severe fetal malformation.We focus on women's individual perception of psychological counselling on decision making, experiencing the birth process, seeing and holding the baby as well as emotional processing. Methods: An explorative study was conducted with 42 women (the age range was between 21 and 45 years [mean 36.17; SD±6.66]) on average twelve months after TOP using semi-structured qualitative interviews. All women received psychological counselling before, during and after the time of TOP (mean 5.2; range 2-11), at the initial counselling session all partners were present. Data were analysed by means of qualitative content analysis by Mayring; the main research question focused on women's perception of psychological counselling on experiencing TOP and coping with this incisive life event. Results: After receiving psychological counselling most of the women felt sufficiently prepared to make a decision, to experience the birth process and to bid farewell to their child. Seeing and holding the baby were perceived as helpful for emotional processing. At the time of the interview, despite the emotional distress,most women reported having positivememories and felt they had coped with the loss. Conclusions: Long-term psychological care from the time of diagnosis through TOP and follow up impacts positively on experiencing TOP, saying farewell to the child and integrating the loss into life. Further studies to detect women at risk for prolonged mourning-reactions are needed.

Sexual health and sexual well-being of women with Mayer-Rokitansky-Kuester-Hauser syndrome after vaginal reconstruction: a qualitative analysis.

BACKGROUND: Contradictory findings on sexual health in women with Mayer-Rokitansky-Kuester-Hauser syndrome (MRKHS) after vaginal reconstruction point toward the need for more profound assessment of this subject, particularly as it is still unclear what constitutes sexual well-being, especially genital self-image or sexual self-esteem, in women with MRKHS and neovagina. AIM: The aim of this qualitative study was to assess individual sexual health and sexual well-being in the context of MRKHS after vaginal reconstruction, with an emphasis on genital self-image, sexual self-esteem, sexual satisfaction, and coping with MRKHS. METHODS: Qualitative semistructured interviews were conducted with women with MRKHS after vaginal reconstruction (n = 10) with the Wharton-Sheares-George surgical method and a matched control group without MRKHS (n = 20). Women were surveyed about their previous and current sexual activities, perception of and attitudes toward their genitals, disclosure to others, coping with the diagnosis, and perception of surgery. Data were analyzed through qualitative content analysis and compared with the control group. OUTCOMES: The primary outcomes of the study were major categories, such as sexual satisfaction, sexual self-esteem, genital self-image, and dealing with MRKHS, as well as subcategories related to the content analysis. RESULTS: Although half the women in the present study indicated that they were coping well with their condition and were satisfied with sexual intercourse, most felt insecure about their neovagina, were cognitively distracted during intercourse, and showed low levels of sexual self-esteem. CLINICAL IMPLICATIONS: A better understanding of expectations and uncertainties regarding the neovagina might help professionals to support women with MRKHS after vaginal reconstruction to increase sexual well-being. STRENGTHS AND LIMITATIONS: This is the first qualitative study focusing on individual aspects of sexual well-being, especially sexual self-esteem and genital self-image, in women with MRKHS and neovagina. The qualitative study indicates good interrater reliability and data saturation. The limitations of this study include the inherent lack of objectivity resulting from the method but also the fact that all the patients had a particular surgical technique, consequently resulting in limited generalizability of these findings. CONCLUSIONS: Our data indicate that integrating the neovagina into the genital self-image is a prolonged process that is essential for sexual well-being and should thus be the focus of sexual counseling.

Circulating microRNAs as molecular biomarkers for lung adenocarcinoma.

BACKGROUND: The potential of microRNAs (miRNAs) as molecular tumor biomarkers for early diagnosis and prognosis in lung cancer is still unclear. OBJECTIVE: To analyze expression of miRNAs in A549 lung adenocarcinoma (LUAD) cells and in primary, non-malignant bronchial epithelial (BE) cells from healthy donors. To analyze the most prominently deregulated miRNAs in plasma samples of LUAD patients and healthy donors. MATERIALS AND METHODS: The expression of 752 miRNAs in LUAD and BE cells was assessed by RT-qPCR with mean-centering restricted normalization. The relative plasma levels of 18 miRNAs in LUAD patients and healthy donors were analyzed using RT-qPCR and normalized to miR-191-5p and miR-16-3p. Putative interactions between miRNAs and their target genes were investigated in silico. RESULTS: Out of 752 miRNAs, 37 miRNAs were significantly deregulated in A549 cells compared to BE cells. MiR-15b-3p, miR-148a-3p, miR-193b-3p, and miR-195-5p were significantly deregulated in plasma samples of LUAD patients compared to donors. The target genes of those four miRNAs are involved in essential mechanisms in cancer development and progression. CONCLUSIONS: There are substantial differences between cancer and control miRNA expression in vitro and in plasma samples of LUAD patients compared to healthy donors. Four deregulated miRNAs are promising as a diagnostic biomarker for adenocarcinoma of the lung.

Outlook of women in science: an interview with our authors.

Diversity in research teams ties alternative perspectives into research projects, and this can fast-forward scientific progress. Concerted efforts have been aimed at encouraging and supporting women to pursue a career in science, yet a gender disparity can still be observed at senior positions, with fewer women in leadership roles. To get insight into how the current landscape for women in science is perceived by different career stages, we interviewed female authors of Molecular Oncology from diverse career stages and disciplines about their inspiration, challenges they have faced as scientists as well as their thoughts on how gender diversity can be further enhanced.

PCK2 opposes mitochondrial respiration and maintains the redox balance in starved lung cancer cells.

Cancer cells frequently lack nutrients like glucose, due to insufficient vascular networks. Mitochondrial phosphoenolpyruvate carboxykinase, PCK2, has recently been found to mediate partial gluconeogenesis and hence anabolic metabolism in glucose starved cancer cells. Here we show that PCK2 acts as a regulator of mitochondrial respiration and maintains the redox balance in nutrient-deprived human lung cancer cells. PCK2 silencing increased the abundance and interconversion of tricarboxylic acid (TCA) cycle intermediates, augmented mitochondrial respiration and enhanced glutathione oxidation under glucose and serum starvation, in a PCK2 re-expression reversible manner. Moreover, enhancing the TCA cycle by PCK2 inhibition severely reduced colony formation of lung cancer cells under starvation. As a conclusion, PCK2 contributes to maintaining a reduced glutathione pool in starved cancer cells besides mediating the biosynthesis of gluconeogenic/glycolytic intermediates. The study sheds light on adaptive responses in cancer cells to nutrient deprivation and shows that PCK2 confers protection against respiration-induced oxidative stress.

Sexuality and Multiple Sclerosis: Patient and Doctor Perspectives.

BACKGROUND: Little is known on how to address sexuality in clinical care for patients with multiple sclerosis (pwMS). AIM: To describe and contrast the perception of sexuality and associated aspects of communication in pwMS and their treating neurologists ("MSologists") and provide a standard of care. METHODS: Patients were surveyed using a 13-item questionnaire investigating perception on their own sexuality and opinions on communication about sexuality in context with MS. Certified MSologists in Austria received an 18-item survey regarding their approach to taking a sexual history of their patients. OUTCOMES: We report the frequency of answers given in this survey and propose a possible standard of care how sexuality could be addressed in clinical routine. RESULTS: Ninety-three pwMS (mean age 39 ± 11 years, 57% female) and 75 MSologists (mean age 43 ± 9 years, 63% male) completed this survey. Seventy-six percent of patients report their own sexuality as being (very) important to them and 95% think that sexual dysfunction would influence their quality of life. 84% would like to be asked about their sexuality by their MSologist. In contrast, only 15% of MSologists reported discussing sexuality with every patient. The most common reason for not doing so was a fear of crossing personal borders (34%). There is a strong desire for further medical education on this subject (76%). CLINICAL IMPLICATIONS: Discussing sexuality is important to pwMS and MSologists should consider their patients' wishes and needs to talk about it. STRENGTHS & LIMITATIONS: This is the largest survey contrasting the views of patients and their treating physicians on the topic of communication about sexuality. The use of an empirical unvalidated questionnaire may have introduced bias. Moreover, patients that are open to talk about their sexuality may be potentially overrepresented in this study. CONCLUSION: MSologists should offer their patients an open opportunity and appropriate framework to discuss their sexuality during a consultation. Altmann P, Leithner K, Leutmezer F, et al. Sexuality and Multiple Sclerosis: Patient and Doctor Perspectives. J Sex Med 2021;18:743-749.

Predisposing Factors for Sexual Dysfunction in Multiple Sclerosis.

Sexual dysfunction (SD) in people with multiple sclerosis (pwMS) has a detrimental impact on individual health-related quality of life (HRQoL). It is not clear whether SD in multiple sclerosis (MS) is an independent symptom or merely a byproduct of other symptoms such as depression or anxiety. This cross-sectional study of 93 pwMS determines risk factors for SD in MS based on prevalence, HRQoL, and associated disease outcomes. Diagnosis of SD was determined based on the Multiple Sclerosis Intimacy and Sexuality Questionnaire-19 (MSISQ-19) and correlated with physical disability (measured by Expanded Disability Status scale, EDSS), depression and anxiety [Hospital Anxiety and Depression Scale (HADS)], and HRQoL [Multiple Sclerosis Quality of Life-54 (MSQoL-54)]. Multivariate regression models were performed to determine independent risk factors for SD in pwMS. Almost half of the participants in this study (46%) reported SD. HRQoL was significantly poorer in patients with MS suffering from SD (median [IQR] MSQoL-54 scores: physical subscale 52 [41-68] vs. 81 [69-89], p < 0.001; mental subscale 50 [38-82] vs. 86 [70-89], p < 0.001). In the multivariate model, EDSS was the only independent risk factor for SD (OR 18.1 for EDSS ≥4 [95% CI 3.3-31.4, p < 0.001]), while depression and anxiety were not. We conclude that the risk for SD is growing with increasing EDSS and is independent of depression or anxiety. Screening for SD becomes particularly relevant in patients with growing disability.

Flexibility and Adaptation of Cancer Cells in a Heterogenous Metabolic Microenvironment.

The metabolic microenvironment, comprising all soluble and insoluble nutrients and co-factors in the extracellular milieu, has a major impact on cancer cell proliferation and survival. A large body of evidence from recent studies suggests that tumor cells show a high degree of metabolic flexibility and adapt to variations in nutrient availability. Insufficient vascular networks and an imbalance of supply and demand shape the metabolic tumor microenvironment, which typically contains a lower concentration of glucose compared to normal tissues. The present review sheds light on the recent literature on adaptive responses in cancer cells to nutrient deprivation. It focuses on the utilization of alternative nutrients in anabolic metabolic pathways in cancer cells, including soluble metabolites and macromolecules and outlines the role of central metabolic enzymes conferring metabolic flexibility, like gluconeogenesis enzymes. Moreover, a conceptual framework for potential therapies targeting metabolically flexible cancer cells is presented.

Phospholipid dynamics in ex vivo lung cancer and normal lung explants.

In cancer cells, metabolic pathways are reprogrammed to promote cell proliferation and growth. While the rewiring of central biosynthetic pathways is being extensively studied, the dynamics of phospholipids in cancer cells are still poorly understood. In our study, we sought to evaluate de novo biosynthesis of glycerophospholipids (GPLs) in ex vivo lung cancer explants and corresponding normal lung tissue from six patients by utilizing a stable isotopic labeling approach. Incorporation of fully 13C-labeled glucose into the backbone of phosphatidylethanolamine (PE), phosphatidylcholine (PC), and phosphatidylinositol (PI) was analyzed by liquid chromatography/mass spectrometry. Lung cancer tissue showed significantly elevated isotopic enrichment within the glycerol backbone of PE, normalized to its incorporation into PI, compared to that in normal lung tissue; however, the size of the PE pool normalized to the size of the PI pool was smaller in tumor tissue. These findings indicate enhanced PE turnover in lung cancer tissue. Elevated biosynthesis of PE in lung cancer tissue was supported by enhanced expression of the PE biosynthesis genes ETNK2 and EPT1 and decreased expression of the PC and PI biosynthesis genes CHPT1 and CDS2, respectively, in different subtypes of lung cancer in publicly available datasets. Our study demonstrates that incorporation of glucose-derived carbons into the glycerol backbone of GPLs can be monitored to study phospholipid dynamics in tumor explants and shows that PE turnover is elevated in lung cancer tissue compared to normal lung tissue.

Three or less? Decision making for or against selective reduction and psychological outcome in forty women with a triplet pregnancy.

OBJECTIVES: The aim of the study was to investigate decision making for or against multifetal pregnancy reduction (MFPR) and psychological outcome in women with a triplet pregnancy. METHODS: We investigated medical and sociodemographic variables and characteristics of the decision process for or against MFPR in forty women with triplet pregnancies who had either undergone MFPR (MFPR-group: N = 10) or had delivered triplets (triplet-group: N = 30). Moreover, emotional experiences of the reduction procedure were assessed. Psychological outcome was measured using the Beck Depression inventory (BDI) and the 36-Item Short Form Health Survey (SF-36). RESULTS: Women of the MFPR-group had a higher gestational age at delivery (p = 0.001), shorter NICU stay (p = 0.001), higher educational level (p = 0.010), more frequently utilized psychological counseling during the decision process (p = 0.016), rated their gynecologist as more helpful for the decision (p = 0.045), required more time for their decision (p = 0.016), and were more likely to be in paid employment at follow-up (p = 0.041) than women of the triplet-group. MFPR was experienced as stressful (90%) or terrifying (10%). At 3.2 (±2.2) years after delivery, the vast majority of women in both groups were free from clinically relevant depression. CONCLUSIONS: MFPR, though associated with emotional distress related to the procedure, results in a satisfactory psychological outcome in the majority of women. The decision for or against MFPR may be related to sociodemographic (such as educational) variables, which further supports the concept of framing in medical decision making. Having triplets most probably is associated with multiple (e.g. social or economic) consequences that may remain poorly investigated.

Distribution and prognostic significance of gluconeogenesis and glycolysis in lung cancer.

Inhibition of glycolysis has been considered as a therapeutic approach in aggressive cancers including lung cancer. Abbreviated gluconeogenesis, mediated by phosphoenolpyruvate carboxykinase (PEPCK), was recently discovered to partially circumvent the need for glycolysis in lung cancer cells. However, the interplay of glycolysis and gluconeogenesis in lung cancer is still poorly understood. Here, we analyzed the expression of GLUT1, the prime glucose transporter, and of PCK1 and PCK2, the cytoplasmic and mitochondrial isoforms of PEPCK, in 450 samples of non-small cell lung cancer (NSCLC) and in 54 NSCLC metastases using tissue microarrays and whole tumor sections. Spatial distribution was assessed by automated image analysis. Additionally, glycolytic and gluconeogenic gene expression was inferred from The Cancer Genome Atlas (TCGA) datasets. We found that PCK2 was preferentially expressed in the lung adenocarcinoma subtype, while GLUT1 expression was higher in squamous cell carcinoma. GLUT1 and PCK2 were inversely correlated, GLUT1 showing elevated expression in larger tumors while PCK2 was highest in smaller tumors. However, a mixed phenotype showing the presence of both, glycolytic and gluconeogenic cancer cells was frequent. In lung adenocarcinoma, PCK2 expression was associated with significantly improved overall survival, while the opposite was found for GLUT1. The metabolic tumor microenvironment and the 3-dimensional context play an important role in modulating both pathways, since PCK2 expression preferentially occurred at the tumor margin and hypoxia regulated both, glycolysis and gluconeogenesis, in NSCLC cells in vitro, albeit in opposite directions. PCK1/2 expression was enhanced in metastases compared to primary tumors, possibly related to the different environment. The results of this study show that glycolysis and gluconeogenesis are activated in NSCLC in a tumor size and oxygenation modulated manner and differentially correlate with outcome. The frequent co-activation of gluconeogenesis and glycolysis in NSCLC should be considered in potential future therapeutic strategies targeting cancer cell metabolism.

Epigenetic Marks Repressing Gluconeogenesis in Liver and Kidney Cancer.

Gluconeogenesis is frequently suppressed in tumors arising in gluconeogenic organs and reexpression of a gluconeogenesis enzyme, fructose-1,6-bisphosphatase (FBP1), was found to inhibit tumor growth. In this issue of Cancer Research, Liao and colleagues show that histone H3 trimethylation on lysine 27, induced by polycomb repressive complex 2 (PRC2), is responsible for downregulating FBP1 in liver and kidney cancer cells. Moreover, they identified FBP1 repression as an important downstream mechanism of PRC2-mediated carcinogenesis. FBP1 inhibits glycolysis but also directly interferes with PRC2 function, thus FBP1 and PRC2 are part of a novel negative feedback loop that is deregulated in liver and kidney cancer.See related article by Liao et al., p. 675.

MicroRNA-182-5p regulates hedgehog signaling pathway and chemosensitivity of cisplatin-resistant lung adenocarcinoma cells via targeting GLI2.

Lung cancer is one of the deadliest cancers worldwide. Late diagnosis at an advanced, inoperable stage makes chemotherapy a treatment of choice, yet, with low response rates. The hedgehog signaling pathway (HHSP) is often reactivated in cancer. We identified miR-182-5p as a regulator of GLI2, a transcriptional regulator of the HHSP, and explored the role of the miR-182-5p/GLI2 axis in carcinogenesis and cisplatin resistance of lung adenocarcinoma (LADC). Expression of miRNAs and target genes was analyzed by RT-qPCR, expression of the GLI-protein family in LADC and adjacent lung tissue (n = 27 pairs) by immunohistochemistry. MiR-182-5p was manipulated, and data were generated by immunoblotting, immunofluorescence, apoptosis, proliferation/viability, dual-luciferase-, and colony forming assays. MiR-182-5p was down-regulated in cisplatin-resistant LADC cells and directly targeted GLI2. Interference with miR-182-5p or GLI2 silencing resulted in modulation of cell proliferation, clonogenic potential, and cisplatin-sensitivity. HHSP was markedly reactivated in LADC tissue compared to adjacent non-malignant lung tissue. Our results indicate that the miR-182-5p/GLI2 axis modulates tumorigenesis and cisplatin-resistance in LADC cells, by influencing the HHSP. Therefore, this axis might be considered as a potential biomarker and future therapeutic target in LADC patients.

Oncogene addiction and tumor mutational burden in non-small-cell lung cancer: Clinical significance and limitations.

Lung cancer incidence has increased worldwide over the past decades, with non-small cell lung cancer (NSCLC) accounting for the vast majority (85%) of lung cancer specimens. It is estimated that lung cancer causes about 1.7 million global deaths per year worldwide. Multiple trials have been carried out, with the aim of finding new effective treatment options. Lately, special focus has been placed on immune checkpoint (PD1/PD-L1) inhibitors which impact the tumor immune microenvironment. Tumor mutational burden (TMB) has been found to predict response to immune checkpoint inhibitors. Conversely, recent studies have weakened the significance of TMB as a predictor of response to therapy and survival. In this review article, we discuss the significance of TMB, as well as possible limitations. Furthermore, we give a concise overview of mutations frequently found in NSCLC, and discuss the significance of oncogene addiction in lung cancer as an essential driver of tumorigenesis and tumor progression.

Gluconeogenesis in cancer cells - Repurposing of a starvation-induced metabolic pathway?

Cancer cells constantly face a fluctuating nutrient supply and interference with adaptive responses might be an effective therapeutic approach. It has been discovered that in the absence of glucose, cancer cells can synthesize crucial metabolites by expressing phosphoenolpyruvate carboxykinase (PEPCK, PCK1 or PCK2) using abbreviated forms of gluconeogenesis. Gluconeogenesis, which in essence is the reverse pathway of glycolysis, uses lactate or amino acids to feed biosynthetic pathways branching from glycolysis. PCK1 and PCK2 have been shown to be critical for the growth of certain cancers. In contrast, fructose-1,6-bisphosphatase 1 (FBP1), a downstream gluconeogenesis enzyme, inhibits glycolysis and tumor growth, partly by non-enzymatic mechanisms. This review sheds light on the current knowledge of cancer cell gluconeogenesis and its role in metabolic reprogramming, cancer cell plasticity, and tumor growth.

The glycerol backbone of phospholipids derives from noncarbohydrate precursors in starved lung cancer cells.

Cancer cells are reprogrammed to consume large amounts of glucose to support anabolic biosynthetic pathways. However, blood perfusion and consequently the supply with glucose are frequently inadequate in solid cancers. PEPCK-M (PCK2), the mitochondrial isoform of phosphoenolpyruvate carboxykinase (PEPCK), has been shown by us and others to be functionally expressed and to mediate gluconeogenesis, the reverse pathway of glycolysis, in different cancer cells. Serine and ribose synthesis have been identified as downstream pathways fed by PEPCK in cancer cells. Here, we report that PEPCK-M-dependent glycerol phosphate formation from noncarbohydrate precursors (glyceroneogenesis) occurs in starved lung cancer cells and supports de novo glycerophospholipid synthesis. Using stable isotope-labeled glutamine and lactate, we show that PEPCK-M generates phosphoenolpyruvate and 3-phosphoglycerate, which are at least partially converted to glycerol phosphate and incorporated into glycerophospholipids (GPL) under glucose and serum starvation. This pathway is required to maintain levels of GPL, especially phosphatidylethanolamine (PE), as shown by stable shRNA-mediated silencing of PEPCK-M in H23 lung cancer cells. PEPCK-M shRNA led to reduced colony formation after starvation, and the effect was partially reversed by the addition of dioleyl-PE. Furthermore, PEPCK-M silencing abrogated cancer growth in a lung cancer cell xenograft model. In conclusion, glycerol phosphate formation for de novo GPL synthesis via glyceroneogenesis is a newly characterized anabolic pathway in cancer cells mediated by PEPCK-M under conditions of severe nutrient deprivation.

No erythropoietin-induced growth is observed in non-small cell lung cancer cells.

Lung cancer patients have the highest incidence of anemia among patients with solid tumors. The use of recombinant human erythropoietin (Epo) has consistently been shown to reduce the need for blood transfusions and to increase hemoglobin levels in lung cancer patients with chemotherapy-induced anemia. However, clinical and preclinical studies have prompted concerns that Epo and the presence of its receptor, EpoR, in tumor cells may be responsible for adverse effects and, eventually, death. The question has been raised whether Epo promotes tumor growth and inhibits the death of cancer cells. In this study, we investigated the presence and functionality of EpoR, as well as the implications of Epo upon the proliferation and survival of lung cancer cells. Since the protein expression of both Epo and EpoR is induced by hypoxia, which is frequently present in lung cancer, the cells were treated with Epo under both normoxic and hypoxic conditions (1% O2). By using quantitative (real-time) PCR, western blot analysis, and immunocytochemical staining, three non-small cell lung cancer (NSCLC) cell lines (A427, A549 and NCI-H358) were analyzed for the expression of EpoR and its specific downstream signaling pathways [Janus kinase 2 (Jak2)-signal transducer and activator of transcription 5 (STAT5), phosphatidylinositol-3-kinase (PI3K)-Akt, mitogen-activated protein (MAP) kinase]. The effects of 100 U/ml Epo on cell proliferation and cisplatin-induced apoptosis were assessed. All NSCLC cell lines expressed EpoR mRNA and protein, while these levels differed considerably between the cell lines. We found the constitutive phosphorylation of EpoR and most of its downstream signaling pathways (STAT5, Akt and ERK1/2) independently of Epo administration. While Epo markedly enhanced the proliferation and reduced apoptosis of Epo-dependent UT-7/Epo leukemia cells, it did not affect tumor cell proliferation or the cisplatin-induced apoptosis of NSCLC cells. Thus, this in vitro study suggests that there are no tumor-promoting effects of Epo in the NSCLC cell lines studied, neither under normoxic nor under hypoxic conditions.