How the Warburg effect supports aggressiveness and drug resistance of cancer cells?

Cancer cells employ both conventional oxidative metabolism and glycolytic anaerobic metabolism. However, their proliferation is marked by a shift towards increasing glycolytic metabolism even in the presence of O₂ (Warburg effect). HIF1, a major hypoxia induced transcription factor, promotes a dissociation between glycolysis and the tricarboxylic acid cycle, a process limiting the efficient production of ATP and citrate which otherwise would arrest glycolysis. The Warburg effect also favors an intracellular alkaline pH which is a driving force in many aspects of cancer cell proliferation (enhancement of glycolysis and cell cycle progression) and of cancer aggressiveness (resistance to various processes including hypoxia, apoptosis, cytotoxic drugs and immune response). This metabolism leads to epigenetic and genetic alterations with the occurrence of multiple new cell phenotypes which enhance cancer cell growth and aggressiveness. In depth understanding of these metabolic changes in cancer cells may lead to the development of novel therapeutic strategies, which when combined with existing cancer treatments, might improve their effectiveness and/or overcome chemoresistance.

A Simple Method to Optimize the Effectiveness of Chemotherapy: Modulation of Glucose Intake During Chemotherapy

BACKGROUND/AIM

Cancer cells consume high amounts of glucose to produce ATP and molecules entering biosynthesis. Numerous experimental studies have demonstrated that glucose deprivation and/or glycolysis inhibition arrest cancer cell growth and may increase the efficiency of cytotoxic drugs. In contrast, increasing glycolysis in tumor-infiltrating lymphocytes (TILs) activates these cells that destroy cancer cells. We propose to increase the efficiency of chemotherapy by modulating glucose intake during the course of chemotherapy.

MATERIALS AND METHODS

Glucose and caloric intake should be drastically reduced the day before and during chemotherapy administration to deprive cancer cells of ATP and molecules required to repair cytotoxic lesions. Few hours after chemotherapy, glucose and caloric intake should be drastically increased for few days to promote the activation of TILs that reinforce the destruction of cancer cells.

RESULTS

This strategy could improve the results of chemotherapy by first enhancing cytotoxic stress against tumor cells and then promoting activation of the anti-cancer immune response.

CONCLUSION

The modulation of glucose intake during chemotherapy should be tested clinically. The proposed scheme is simple, surely easier to follow than a strict chronic diet, and should avoid weight loss.

Do atmospheric conditions influence the first episode of primary spontaneous pneumothorax?

OBJECTIVES

Several studies suggest that changes in airway pressure may influence the onset of primary spontaneous pneumothorax (PSP). The aim of this study was to investigate the influence of atmospheric changes on the onset of the first episode of PSP.

METHODS

We retrospectively analysed cases of pneumothorax admitted to our department between 1 January 2009 and 31 October 2013. Patients with recurrent pneumothorax, traumatic pneumothorax, older than 35 years or presenting history of underlying pulmonary disease were excluded. Meteorological data were collected from the Météo-France archives. Variation (Δ) of mean atmospheric pressure, and relative humidity, were calculated for each day between the day at which symptoms began (D-day), the day before first symptoms (D-1), 2 days before the first symptoms (D-2) and 3 days before the first symptoms (D-3).

RESULTS

Six hundred and thirty-eight cases of pneumothorax were observed during the period of this study; 106 of them (16.6%) were a first episode of PSP. We did not observe any significant differences between days with or without PSP admission for any of the weather parameters that we tested. We could not find any thresholds in the variation of atmospheric pressure that could be used to determine the probability of PSP occurrence.

CONCLUSIONS

Variation of atmospheric pressure, relative humidity, rainfall, wind speed and temperature were not significantly related to the onset of the first episode of PSP in healthy patients. These results suggest that the scientific community should focus on other possible aetiological factors than airway pressure modifications.

How do glycolytic enzymes favour cancer cell proliferation by nonmetabolic functions?

Cancer cells enhance their glycolysis, producing lactate, even in the presence of oxygen. Glycolysis is a series of ten metabolic reactions catalysed by enzymes whose expression is most often increased in tumour cells. HKII and phosphoglucose isomerase (PGI) have mainly an antiapoptotic effect; PGI and glyceraldehyde-3-phosphate dehydrogenase activate survival pathways (Akt and so on); phosphofructokinase 1 and triose phosphate isomerase participate in cell cycle activation; aldolase promotes epithelial mesenchymal transition; PKM2 enhances various nuclear effects such as transcription, stabilisation and so on. This review outlines the multiple non-glycolytic roles of glycolytic enzymes, which are essential for promoting cancer cells' survival, proliferation, chemoresistance and dissemination.

Migration of a Kirschner pin from the shoulder to the lung, requiring surgery

A 62-year-old woman underwent a reduction of a proximal reduced humeral fracture, which was fixed by 3 Kirschner pins. One year later, the orthopedic surgeon failed to remove one of the wires. The patient was lost to follow-up, and 4 years later, she presented with hemoptysis, revealing migration of the pin to the lung. The pin was removed through a thoracotomy. Migration to the lung is often revealed by hemoptysis or pneumothorax. Close follow-up and early removal of the pins are mandatory.

A misleading cause of pseudo-thymic tumor in ectopic Cushing's syndrome

A 27-year-old man was referred with typical features of severe Cushing's syndrome. A bilateral adrenalectomy was performed. Three months later, a triangular nodular mediastinal enlargement, evocative of a right anterior thymic tumor, was discovered. Thymectomy was undertaken. Histological examination revealed diffuse thymic hyperplasia with negative immunostaining for adrenocorticotropic hormone. Five years later, a right endobronchial tumor corresponding to a carcinoid tumor was removed.

Metabolic treatment of cancer: intermediate results of a prospective case series

BACKGROUND

The combination of hydroxycitrate and lipoic acid has been demonstrated by several laboratories to be effective in reducing murine cancer growth.

PATIENTS AND METHODS

All patients had failed standard chemotherapy and were offered only palliative care by their referring oncologist. Karnofsky status was between 50 and 80. Life expectancy was estimated to be between 2 and 6 months. Ten consecutive patients with chemoresistant advanced metastatic cancer were offered compassionate metabolic treatment. They were treated with a combination of lipoic acid at 600 mg i.v. (Thioctacid), hydroxycitrate at 500 mg t.i.d. (Solgar) and low-dose naltrexone at 5 mg (Revia) at bedtime. Primary sites were lung carcinoma (n=2), colonic carcinoma (n=2), ovarian carcinoma (n=1), esophageal carcinoma (n=1), uterine sarcoma (n=1), cholangiocarcinoma (n=1), parotid carcinoma (n=1) and unknown primary (n=1). The patients had been heavily pre-treated. One patient had received four lines of chemotherapy, four patients three lines, four patients two lines and one patient had received radiation therapy and chemotherapy. An eleventh patient with advanced prostate cancer resistant to hormonotherapy treated with hydroxycitrate, lipoic acid and anti-androgen is also reported.

RESULTS

One patient was unable to receive i.v. lipoic acid and was switched to oral lipoic acid (Tiobec). Toxicity was limited to transient nausea and vomiting. Two patients died of progressive disease within two months. Two other patients had to be switched to conventional chemotherapy combined with metabolic treatment, one of when had a subsequent dramatic tumor response. Disease in the other patients was either stable or very slowly progressive. The patient with hormone-resistant prostate cancer had a dramatic fall in Prostate-Specific Antigen (90%), which is still decreasing.

CONCLUSION

These very primary results suggest the lack of toxicity and the probable efficacy of metabolic treatment in chemoresistant advanced carcinoma. It is also probable that metabolic treatment enhances the efficacy of cytotoxic chemotherapy. These results are in line with published animal data. A randomized clinical trial is warranted.

Morbidity, mortality and survival after 110 consecutive bilobectomies over 12 years

OBJECTIVES

To analyse statistical aspects of mortality, morbidity and survival after bilobectomy (BT), an operation rarely studied in the literature.

METHODS

One hundred and ten cases were studied, comprising 58 upper-middle bilobectomies and 52 lower-middle bilobectomies performed between 1999 and 2010. Indications were of 9 benign diseases, 12 carcinoid tumours, 5 metastases and 84 non-small cell lung cancers (2 stage 0; 34 stage I; 22 stage II; 25 stage III and 1 stage IV).

RESULTS

Mortality was nil. Twenty-six percent of patients experienced significant morbidity, influenced in multivariate analysis by the presence of three or more comorbidities (P = 0.03) and by a forced expiratory volume in 1 s of <60% (P = 0.01). Lower-middle BT was associated with more postoperative complications than upper-middle BT (P = 0.012). The 5-year survival rate of patients with non-small cell lung carcinoma was 82% in stage I, 59% in stage II and 20% in stage IIIA. Survival was significantly influenced by stage (P = 0.0018) and tobacco weaning (P = 0.0012).

CONCLUSIONS

BT can be achieved with low mortality, and survival results that are comparable with those unregistered after standard lobectomy. However, almost one quarter of patients experienced significant postoperative complications. Surgical techniques aiming to reduce residual pleural space should be especially considered after lower-middle BT, due to the highest morbidity being associated with this procedure.

siPGK1 sensitizes chemoresistant human ovarian cancer cell lines to cisplatin

Enhanced glycolysis provides essential intermediates for cancer cell proliferation. Its inhibition could be a promising approach for destroying tumors, especially those developing in hypoxic conditions, which are presumably the most chemoresistant. In hypoxic cells, glycolysis provides the main part of ATP. Phosphoglycerate kinase-1 (PGK1) catalyzes a crucial reaction of glycolysis that reconstitutes the two molecules of ATP previously consumed. PGK1 inhibition could arrest growth or kill hypoxic and/or chemoresistant cells. We tested siPGK1 transfection in two human ovarian cancer cells lines of increasing chemoresistance, and showed that: Expression of PGK1 was significantly reduced and associated with blockade of cell growth in the G(1) phase; siPGK1 associated with cisplatin was more effective than cisplatin-alone at inhibiting proliferation of chemoresistant cells; siPGK1 -alone and -associated with cisplatin strongly increased expression of the BH3-only pro-apoptotic protein BCL-2 Interacting Mediator of cell death (BIM). PGK1 might be a key target for sensitizing chemoresistant cells to cisplatin.

Pulmonary botryomycosis on a lung cavity: a rare pulmonary infection mimicking cancer

Lung botryomycosis is a rare disease. We report what is to our knowledge the first case occurring on a lung cavity. In a 42-year-old man suffering asthenia and cough, a chest radiograph revealed a right upper lobe opacity. Computed tomography scan showed a necrotic mass which was also spiculated. Repeated research for Mycobacterium tuberculosis was negative. The patient underwent a lobectomy. Histological and bacteriological examinations made the diagnosis of botryomycosis, because the cavity presented numerous colonies of pyogenic Fusobacterium nucleatum bacteria. Botryomycosis is a difficult diagnosis that clinically mimics actinomycosis, tuberculosis or cancer. In most cases, surgery is necessary to assess diagnosis and treatment.

Understanding the central role of citrate in the metabolism of cancer cells

Cancers cells strongly stimulate glycolysis and glutaminolysis for their biosynthesis. Pyruvate derived from glucose is preferentially diverted towards the production of lactic acid (Warburg effect). Citrate censors ATP production and controls strategic enzymes of anabolic and catabolic pathways through feedback reactions. Mitochondrial citrate diffuses in the cytosol to restore oxaloacetate and acetyl-CoA. Whereas acetyl-CoA serves de novo lipid synthesis and histone acetylation, OAA is derived towards lactate production via pyruvate and / or a vicious cycle reforming mitochondrial citrate. This cycle allows cancer cells to burn their host's lipid and protein reserves in order to sustain their own biosynthesis pathways. In vitro, citrate has demonstrated anti-cancer properties when administered in excess, sensitizing cancer cells to chemotherapy. Understanding its central role is of particular relevance for the development of new strategies for counteracting cancer cell proliferation and overcoming chemoresistance.

Citrate induces apoptotic cell death: a promising way to treat gastric carcinoma?

Gastric carcinoma is frequent, particularly in China, and therapy is often inefficient. Because cancer cells are partly or mainly dependent on glycolysis to generate adenosine triphosphate ATP (Warburg effect) and/or to produce precursors (of lipid, nucleotides, etc.) for building new cells, any inhibition of glycolysis may slow down the cell proliferation and/or may kill cells. The antitumor effect of citrate, an anti-glycolytic agent inhibiting phosphofructokinase (PFK) was tested on two human gastric carcinoma cell lines.

MATERIALS AND METHODS

Cell viability and morphology were assessed after 24-72 h exposure to citrate (5, 10, 220 mM). Apoptosis was assessed by annexin V-FITC/PI staining and Western immunobloting.

RESULTS

A 3-day continuous exposure to citrate led to near destruction of the cell population in both cell lines, apoptotic cell death occurred through the mitochondrial pathway in a dose- and time-dependent manner, associated with the reduction of the anti-apoptotic Mcl-1 protein in both lines.

CONCLUSION

Citrate demonstrates strong cytotoxic activity against two gastric cancer lines, leading to an early diminution of expression of Mcl-1 and to massive apoptotic cell death involving the mitochondrial pathway.

Downregulation of Bcl-xL and Mcl-1 is sufficient to induce cell death in mesothelioma cells highly refractory to conventional chemotherapy

Malignant pleural mesothelioma (MPM) is an aggressive tumor with poor prognosis and limited response to platinum-based chemotherapy. Several lines of evidence support a role for the anti-apoptotic protein Bcl-x(L) in MPM chemoresistance. Since it has been recently suggested that Mcl-1 cooperates with Bcl-x(L) for protection against cell death, we investigated the response of mesothelioma cell lines to the downregulation of Bcl-x(L) (alone or in combination with cisplatin) and the potential interest of its concomitant inhibition with that of Mcl-1. Using RNA interference, we showed that Bcl-x(L) depletion sensitized two highly chemoresistant mesothelioma cell lines to cisplatin and that under this treatment, one cell line, MSTO-211H, displayed an apoptotic type of cell death, whereas the other, NCI-H28, evidenced mainly necrotic-type cell death. Otherwise, the inhibition of Mcl-1 by cisplatin may contribute to this induction of cell death observed after Bcl-x(L) downregulation. Strikingly, we observed that the simultaneous inhibition of Bcl-x(L) and Mcl-1 using small interfering RNA (siRNA) induced a massive cell death in the absence of chemotherapy and was sufficient to avoid escape to treatment in MSTO-211H cells. In NCI-H28, the addition of a low cisplatin concentration allowed to impede the long-term recovery observed after treatment by the siRNA combination. Together, these findings provide a strong molecular basis for the clinical evaluation of therapies targeting both Bcl-x(L) and Mcl-1, alone or in combination with conventional chemotherapy, for the treatment of MPM.

Social-behavioural functioning in paediatric chronic kidney disease

Background The social-behavioural functioning of children and adolescents with chronic kidney disease (CKD) is not well studied and not fully understood, with available studies reflecting a mixed set of findings. The primary purpose of this paper is to compare the social-behavioural functioning of children with CKD with typical controls using multiple raters. A secondary analysis also examines the impact of disease severity on social-behavioural functioning. Methods Parental ratings and self-reports on the Behavior Assessment System for Children were obtained from a patient sample of 26 children and adolescents with CKD. This sample was comprised of those with end-stage renal disease (end-stage renal disease; n= 13) and those with chronic renal insufficiency (n= 13). For comparison, a typically developing control group (n= 33) also was ascertained. Results While behaviour ratings by parents and children fell within the average range, parent ratings showed an increased number of internalizing symptoms when compared with the CKD Group. Exploratory analyses revealed parental ratings showing more specific concerns on the Behavior Assessment System for Children individual clinical scales of Anxiety, Depression and Somatization. No differences were observed between the groups on the children's self-ratings, or in terms of numbers of children falling above the 90th percentile for both parent and child ratings. Secondary analyses did not produce any group differences between the chronic renal insufficiency and end-stage renal disease severity groupings. Conclusions These findings failed to show the presence of social-behavioural difficulties in children with CKD, although there may be specific concerns for the presence of internalizing symptoms as per parent ratings. These findings suggest the need for follow-up of the subtle affective symptoms that might be present in children with CKD as recognizing these subthreshold social-behavioural symptoms may be a critical part of their overall clinical care.

Effect of citrate on malignant pleural mesothelioma cells: a synergistic effect with cisplatin

BACKGROUND

Because cancer cells are partly or mainly dependent on glycolysis to generate ATP (Warburg effect), any inhibition of glycolysis may slow down their proliferation or kill them.

MATERIALS AND METHODS

The anti-tumor effect of citrate, an inhibitor of phosphofructokinase, was tested on particularly chemoresistant MSTO-211H human mesothelioma cells.

RESULTS

A 3-day continuous exposure to citrate led to apoptotic cell death via a mitochondrial pathway, associated with a reduction of anti-apoptotic protein Bcl-x(L) and Mcl-1 expression. However, when citrate was removed, the remaining cells resumed their proliferation. The treatment of cells with a non-cytotoxic dose of cisplatin at the end of the citrate exposure led to a strong cytotoxicity, almost all cells being killed.

CONCLUSION

Depletion of ATP, diminution of the expression of the anti-apoptotic proteins and inhibition of hexokinase secondary to inhibition of phosphofructokinase by citrate may explain the cytotoxic activity of this molecule and its synergistic effect with cisplatin.

Novel therapy for malignant pleural mesothelioma based on anti-energetic effect: an experimental study using 3-Bromopyruvate on nude mice

BACKGROUND

Most cancer cells exhibit increased anaerobic glycolysis and use this metabolic pathway for the generation of ATP as a main source of energy. This impaired metabolism of glucose, leading to the secretion of lactic acid even in the presence of oxygen, is named the Warburg effect. Because cancer cells are partly or mainly dependent on such a pathway to generate ATP, inhibition of glycolysis may slow down the proliferation or kill cells.

MATERIALS AND METHODS

The effect of 3-Bromopyruvate (3-BrPA) alone or associated to cisplatin on nude mice presenting intraperitoneal carcinomatosis developed after intraperitoneal injection of human mesothelioma cells (MSTO-211H) was investigated.

RESULTS

3-BrPA significantly prolonged survival of animals. Combined with cisplatin, it demonstrated significant benefit on survival whereas cisplatin alone had no or a mild effect.

CONCLUSION

3-BrPA may thus constitute an interesting novel anticancer drug that could be tested in humans.

A single 24F Blake drain after wedge resection or lobectomy: a study on 100 consecutive cases

OBJECTIVE

To evaluate the results of chest drainage using one 24F Blake drain after standard thoracic operations (wedge resection and lobectomy).

METHODS

In 2005, 100 consecutive patients underwent drainage of their pleural cavity following lobectomy or wedge resection(s). There were 70 men and 30 women, with a mean age of 55 years (17-83). There were 47 lobectomies (23 upper, 5 middle, 19 lower), 3 bilobectomies (2 right upper and middle, 1 right lower and middle), and 2 anatomical segmentectomies. All these anatomical resections were performed by standard thoracotomy, mainly for cancer diseases (45 cases). Furthermore, 48 atypical resections by single or multiple wedge(s) were realized, 20 of them by VATS. They included 14 various benign diseases, 16 malignant diseases, 8 significant emphysema bullous, and 10 blebs. Chest X rays were performed regularly in the postoperative period to detect residual pleural effusion or pneumothorax necessitating additional drainage or reoperation. Patients were controlled one month after discharge.

RESULTS

One patient with pleural carcinosis died of pulmonary embolus on day 8. Neither replacement of chest tube nor reoperation was necessary for pleural space problems. Median duration of drainage was 5 days (3-15), 6 days after lobectomy and 4 days after wedge resection. In 15 cases, the duration of drainage was more than 8 days: 11 persistent air leaks and 4 drainages exceeding 150-200 cm3 daily. Ninety percent of patients were discharged the day following the drain removal.

CONCLUSIONS

Postoperative courses after standard thoracic procedures using a single 24F Blake drainage appear similar to that accounting after a classical semi-rigid drainage. Such single drainage may appear now as an acceptable option. The flexible quality of the drain, its reduced caliber, and the character unique of the drainage, may contribute to improve comfort of the operated patients.