Magnesium and tumors: Ally or foe?

Spectroscopic diagnosis and metabolite characterization of cisplatin resistance regulated by FDFT1 in bladder cancer tissue

As is the case for most solid tumours, chemotherapy remains the backbone in the management of metastatic disease. However, the occurrence of chemotherapy resistance is a cause to worry, especially in bladder cancer. Extensive evidence indicates molecular changes in bladder cancer cells to be the underlying cause of chemotherapy resistance, including the reduced expression of farnesyl-diphosphate farnesyltransferase 1 (FDFT1) - a gene involved in cholesterol biosynthesis. This can likely be a hallmark in examining the resistance and sensitivity of chemotherapy drugs. This work performs spectroscopic analysis and metabolite characterization on resistant, sensitive, stable-disease and healthy bladder tissues. Raman spectroscopy has detected peaks at around 1003 cm-1 (squalene), 1178 cm-1 (cholesterol), 1258 cm-1 (cholesteryl ester), 1343 cm-1 (collagen), 1525 cm-1 (carotenoid), 1575 cm-1 (DNA bases) and 1608 cm-1 (cytosine). The peak parameters were examined, and statistical analysis was performed on the peak features, attaining significant differences between the sample groups. Small-angle x-ray scattering (SAXS) measurements observed the triglyceride peak together with 6th, 7th and 8th - order collagen peaks; peak parameters were also determined. Neutron activation analysis (NAA) detected seven trace elements. Carbon (Ca), magnesium (Mg), chlorine (Cl) and sodium (Na) have been found to have the greatest concentration in the sample groups, suggestive of a role as a biomarker for cisplatin resistance studies. Results from the present research are suggested to provide an important insight into understanding the development of drug resistance in bladder cancer, opening up the possibility of novel avenues for treatment through personalised interventions.

Does insulin make breast cancer cells resistant to doxorubicin toxicity?

The effects of insulin on the doxorubicin (Dox) sensitivity of breast cancer cell line MCF-7 and its Dox-resistant counterpart MCF-7/Dox were studied and glucose metabolism, content of essential minerals, and the expression of several microRNAs in these cells upon exposure to insulin and Dox were compared. Cell viability colorimetric assay, colorimetric enzymatic technique, flow cytometry, immunocytochemical techniques, inductively-coupled plasma atomic emission spectroscopy, and quantitative polymerase chain reaction were used in the study. We found that insulin in high concentration significantly suppressed Dox toxicity, especially in parental MCF-7 cell line. The increase in proliferative activity triggered by insulin in MCF-7 but not MCF-7/Dox cells occurred in the setting of the increased level of specific binding sites for insulin and increased glucose uptake. Insulin treatment of MCF-7 cells in low and high concentrations resulted in the increase of Mg, Ca, and Zn content while in DOX-resistant cells, only Mg content increased upon exposure to insulin. High concentration of insulin increased the expression of kinase Akt1, P-glycoprotein 1 (P-gp1) and DNA excision repair protein ERCC-1 in MCF-7 cells, while in MCF-7/Dox cells, Akt1 expression decreased, and cytoplasmic expression of P-gp1 increased. In addition, insulin treatment affected expression of miR-122-5p, miR-133a-3p, miR-200b-3p, and miR-320a-3p. The decreased manifestation of biological effects of insulin in Dox-resistant cells could be partly explained by the different patterns of energy metabolism in MCF-7 cells and their Dox-resistant counterpart.

Inorganic material based macrophage regulation for cancer therapy: basic concepts and recent advances

Macrophages with the M1 phenotype are a type of immune cell with exciting prospects for cancer therapy; however, when these macrophages infiltrate into tumours, many of them are induced by the tumour microenvironment to transform into the M2 type, which can enable tumour defence against external therapeutic strategies, assisting in tumour development. Macrophages have strong plasticity and functional heterogeneity, and their phenotypic transformation is complex and still poorly understood in relation to cancer therapy. Recent material advances in inorganic nanomaterials, especially inorganic elements in vivo, have accelerated the development of macrophage regulation-based cancer treatments. This review summarizes the basics of recent research on macrophage phenotype transformation and discusses the current challenges in macrophage type regulation. Then, the current achievements involving inorganic material-based macrophage regulation and the related anticancer effects of induced macrophages and their extracellular secretions are reviewed systematically. Importantly, inorganic nanomaterial-based macrophage phenotype regulation is flexible and can be adapted for different types of cancer therapies, presenting a possible novel approach for the generation of immune materials for cancer therapy.

Assessment and Imaging of Intracellular Magnesium in SaOS-2 Osteosarcoma Cells and Its Role in Proliferation

Magnesium is an essential nutrient involved in many important processes in living organisms, including protein synthesis, cellular energy production and storage, cell growth and nucleic acid synthesis. In this study, we analysed the effect of magnesium deficiency on the proliferation of SaOS-2 osteosarcoma cells. When quiescent magnesium-starved cells were induced to proliferate by serum addition, the magnesium content was 2–3 times lower in cells maintained in a medium without magnesium compared with cells growing in the presence of the ion. Magnesium depletion inhibited cell cycle progression and caused the inhibition of cell proliferation, which was associated with mTOR hypophosphorylation at Serine 2448. In order to map the intracellular magnesium distribution, an analytical approach using synchrotron-based X-ray techniques was applied. When cell growth was stimulated, magnesium was mainly localized near the plasma membrane in cells maintained in a medium without magnesium. In non-proliferating cells growing in the presence of the ion, high concentration areas inside the cell were observed. These results support the role of magnesium in the control of cell proliferation, suggesting that mTOR may represent an important target for the antiproliferative effect of magnesium. Selective control of magnesium availability could be a useful strategy for inhibiting osteosarcoma cell growth.

Imbalance of Mg Homeostasis as a Potential Biomarker in Colon Cancer

BACKGROUND

Increasing evidences support a correlation between magnesium (Mg) homeostasis and colorectal cancer (CRC). Nevertheless, the role of Mg and its transporters as diagnostic markers in CRC is still a matter of debate. In this study we combined X-ray Fluorescence Microscopy and databases information to investigate the possible correlation between Mg imbalance and CRC.

METHODS

CRC tissue samples and their non-tumoural counterpart from four patients were collected and analysed for total Mg level and distribution by X-Ray Fluorescence Microscopy. We also reviewed the scientific literature and the main tissue expression databases to collect data on Mg transporters expression in CRC.

RESULTS

We found a significantly higher content of total Mg in CRC samples when compared to non-tumoural tissues. Mg distribution was also impaired in CRC. Conversely, we evidenced an uncertain correlation between Mg transporters expression and colon malignancies.

DISCUSSION

Although further studies are necessary to determine the correlation between different cancer types and stages, this is the first report proposing the measurement of Mg tissue localisation as a marker in CRC. This study represents thus a proof-of-concept that paves the way for the design of a larger prospective investigation of Mg in CRC.

Plasma Magnesium Concentrations and Risk of Incident Cancer in Adults with Hypertension: A Nested Case-Control Study

OBJECTIVE

The association between plasma magnesium and risk of incident cancer remains inconclusive in previous studies. We aimed to investigate the prospective relationship of baseline plasma magnesium concentrations with the risk of incident cancer and to examine possible effect modifiers.

METHODS

A nested case-control study with 228 incident cancer cases and 228 matched controls was conducted using data from the China Stroke Primary Prevention Trial (CSPPT), a randomized, double-blind, controlled trial, conducted from May 2008 to August 2013. Study outcomes included incident cancer and its subtypes.

RESULTS

When plasma magnesium concentrations were assessed as quartiles, a significantly higher incident risk of total cancer was found in participants in quartile 1 (<0.76 mmol/L; odds ratio [OR] = 2.70; 95% CI: 1.33-5.49) and quartile 4 (≥0.89 mmol/L; OR = 2.05; 95% CI: 1.12-3.76), compared with those in quartile 3 (0.83 to <0.89 mmol/L). In cancer site-specific analyses, similar trends were found for gastrointestinal cancer, esophageal cancer, gastric cancer, breast cancer, lung cancer, and other cancers. Furthermore, none of the variables, including age, sex, current smoking status, current alcohol intake, BMI, systolic blood pressure, and total cholesterol levels at baseline significantly modified the association between plasma magnesium and cancer risk.

CONCLUSIONS

Both low and high plasma magnesium concentrations were significantly associated with an increased incident risk of cancer, compared with the reference concentrations of 0.83 to <0.89 mmol/L among hypertensive adults.

Magnesium Absorption in Intestinal Cells: Evidence of Cross-Talk between EGF and TRPM6 and Novel Implications for Cetuximab Therapy

Hypomagnesemia is very commonly observed in cancer patients, most frequently in association with therapy with cetuximab (CTX), a monoclonal antibody targeting the epithelial growth factor receptor (EGFR). CTX-induced hypomagnesemia has been ascribed to renal magnesium (Mg) wasting. Here, we sought to clarify whether CTX may also influence intestinal Mg absorption and if Mg supplementation may interfere with CTX activity. We used human colon carcinoma CaCo-2 cells as an in vitro model to study the mechanisms underlying Mg transport and CTX activity. Our findings demonstrate that TRPM6 is the key channel that mediates Mg influx in intestinal cells and that EGF stimulates such influx; consequently, CTX downregulates TRPM6-mediated Mg influx by interfering with EGF signaling. Moreover, we show that Mg supplementation does not modify either the CTX IC50 or CTX-dependent inhibition of ERK1/2 phosphorylation. Our results suggest that reduced Mg absorption in the intestine may contribute to the severe hypomagnesemia that occurs in CTX-treated patients, and Mg supplementation may represent a safe and effective nutritional intervention to restore Mg status without impairing the CTX efficacy.

Optimizing an Osteosarcoma-Fibroblast Coculture Model to Study Antitumoral Activity of Magnesium-Based Biomaterials

Osteosarcoma is among the most common cancers in young patients and is responsible for one-tenth of all cancer-related deaths in children. Surgery often leads to bone defects in excised tissue, while residual cancer cells may remain. Degradable magnesium alloys get increasing attention as orthopedic implants, and some studies have reported potential antitumor activity. However, most of the studies do not take the complex interaction between malignant cells and their surrounding stroma into account. Here, we applied a coculture model consisting of green fluorescent osteosarcoma cells and red fluorescent fibroblasts on extruded Mg and Mg-6Ag with a tailored degradation rate. In contrast to non-degrading Ti-based material, both Mg-based materials reduced relative tumor cell numbers. Comparing the influence of the material on a sparse and dense coculture, relative cell numbers were found to be statistically different, thus relevant, while magnesium alloy degradations were observed as cell density-independent. We concluded that the sparse coculture model is a suitable mechanistic system to further study the antitumor effects of Mg-based material.

Effect of magnesium-degradation products and hypoxia on the angiogenesis of human umbilical vein endothelial cells

Biodegradable magnesium (Mg) metals have been applied in orthopaedic and stent applications due to their biodegradability, bioabsorbability and adaptability to tissue regeneration. However, further investigations are still needed to understand how angiogenesis will respond to high concentrations of Mg and oxygen content differences, which are vital to vascular remodelling and bone fracture regeneration or tissue healing. Human primary endothelial cells were exposed to various concentrations (2-8 mM) of extracellular Mg degradation products under either hypoxia or normoxia. Increased proliferation was measured with Mg extracts under hypoxia but not under normoxia. Under normoxia and with Mg extracts, HUVEC migration exhibited a bell-shaped curve. The same pattern was observed with VEGFB expression, while VEGFA was constantly downregulated. Under hypoxia, migration and VEGFA levels remained constant; however, VEGFB was upregulated. Similarly, under normoxia, tube formation as well as VEGFA and VEGFB levels were downregulated. Nevertheless, under hypoxia, tube formation remained constant while VEGFA and VEGFB levels were upregulated. These results suggest that Mg extracts did not interfere with angiogenesis under hypoxia. STATEMENT OF SIGNIFICANCE: Neoangiogenesis, mediated by (e.g.) hypoxia, is a key factor for proper tissue healing Thus, effect of Mg degradation products under either hypoxia or normoxia on angiogenesis were investigated. Under normoxia and increased Mg concentrations, a general negative effect was measured on early (migration) and late (tubulogenesis) angiogenesis. However, under hypoxia, this effect was abolished. As magnesium degradation is an oxygen-dependant process, hypoxia condition may be a relevant factor to test material cytocompatibility in vitro.

New Aspects of Magnesium Function: A Key Regulator in Nucleosome Self-Assembly, Chromatin Folding and Phase Separation

Metal cations are associated with many biological processes. The effects of these cations on nucleic acids and chromatin were extensively studied in the early stages of nucleic acid and chromatin research. The results revealed that some monovalent and divalent metal cations, including Mg²⁺, profoundly affect the conformations and stabilities of nucleic acids, the folding of chromatin fibers, and the extent of chromosome condensation. Apart from these effects, there have only been a few reports on the functions of these cations. In 2007 and 2013, however, Mg²⁺-implicated novel phenomena were found: Mg²⁺ facilitates or enables both self-assembly of identical double-stranded (ds) DNA molecules and self-assembly of identical nucleosomes in vitro. These phenomena may be deeply implicated in the heterochromatin domain formation and chromatin-based phase separation. Furthermore, a recent study showed that elevation of the intranuclear Mg²⁺ concentration causes unusual differentiation of mouse ES (embryonic stem) cells. All of these phenomena seem to be closely related to one another. Mg²⁺ seems to be a key regulator of chromatin dynamics and chromatin-based biological processes.

Magnesium in Breast Cancer: What Is Its Influence on the Progression of This Disease?

Breast cancer is a disease of high mortality, characterized by the progressive accumulation of mutations that contribute to the uncontrolled development of breast tissue cells. Literature shows that disturbances in mineral homeostasis, such as magnesium, may interfere with tumor progression. The objective of this study is to provide updated information about magnesium's role in the pathogenesis of breast cancer. A review of literature was carried out from a search for articles in the PubMed and CAPES Periodicals databases published between 1995 and 2016 with the cross-references of the descriptors "magnesium," "breast neoplasms," and "oxidative stress" and the corresponding words in Portuguese. We included studies on the metabolism and bioavailability of magnesium and studies related to breast cancer and excluded articles in which only the abstract was available, dissertations, theses, articles involving adjuvant and/or neoadjuvant therapies, and supplementation of minerals in breast cancer patients. Magnesium is a mineral that participates in the metabolism of various nutrients and nucleic acids. In the presence of breast cancer, neoplastic cells increase the expression of magnesium transport channels, which raises the intracellular concentration of the mineral, contributing to tumor growth through its function of increasing energy demand. The data obtained in this review illustrates the influence of magnesium on the progression of breast cancer. However, the existing data are scarce and inconsistent, which demonstrates a need for further studies on the subject with a goal to have better control of the disease.

Hypomagnesemia and clinical benefits of anti-EGFR monoclonal antibodies in wild-type KRAS metastatic colorectal cancer: a systematic review and meta-analysis

Hypomagnesemia is a recognized side-effect of cetuximab- or panitumumab-based chemotherapy for metastatic colorectal cancer (mCRC). The clinical relevance of hypomagnesemia is under debate. Thus, a systematic review and meta-analysis of retrospective studies and randomized clinical trials (RCTs) comparing hypomagnesemia with normal magnesium levels in wild-type KRAS mCRC was performed. One RCT, two retrospective studies, and two American Society of Clinical Oncology (ASCO) and European Society for Medical Oncology (ESMO) conference presentations from phase III RCTs involving 1723 patients were included in this study. Patients with hypomagnesemia demonstrated better progression-free survival (PFS) (Hazard ratio [HR]: 0.64; 95% confidence interval [CI]: 0.47–0.88), overall survival (OS) (HR: 0.72; 95% CI: 0.53–0.92), and objective response rate (ORR) (Risk ratio [RR]: 1.81; 95% confidence interval [CI]: 1.30–2.52). By subgroup analysis, frontline, later lines or combination therapy with hypomagnesemia were associated with PFS benefits (HR: 0.78; 95% CI: 0.62–0.98; HR: 0.60; 95% CI: 0.40–0.90; HR: 0.62; 95% CI: 0.41–0.94, respectively). In patients with wild-type KRAS mCRC, hypomagnesemia is associated with better clinical benefits of PFS, OS and ORR when treated with cetuximab- or panitumumab-based chemotherapy. Future clinical trials should corroborate its predictive role.

Inhibition of TRPM7 suppresses cell proliferation of colon adenocarcinoma in vitro and induces hypomagnesemia in vivo without affecting azoxymethane-induced early colon cancer in mice

BACKGROUND

Magnesium (Mg2+) is an essential cation implicated in carcinogenesis, solid tumor progression and metastatic potential. The Transient Receptor Potential Melastatin Member 7 (TRPM7) is a divalent ion channel involved in cellular and systemic Mg2+ homeostasis. Abnormal expression of TRPM7 is found in numerous cancers, including colon, implicating TRPM7 in this process.

METHODS

To establish a possible link between systemic magnesium (Mg2+) status, the Mg2+ conducting channel TRPM7 in colon epithelial cells, and colon carcinogenesis, in vitro whole-cell patch clamp electrophysiology, qPCR, and pharmacological tools were used probing human colorectal adenocarcinoma HT-29 as well as normal primary mouse colon epithelial cells. This was extended to and combined with aberrant crypt foci development in an azoxymethane-induced colorectal cancer mouse model under hypomagnesemia induced by diet or pharmacologic intervention.

RESULTS

We find that TRPM7 drives colon cancer cell proliferation in human HT-29 and expresses in normal primary mouse colon epithelia. This is linked to TRPM7's dominant role as Mg2+ transporter, since high extracellular Mg2+ supplementation cannot rescue inhibition of cell proliferation caused by suppressing TRPM7 either genetically or pharmacologically. In vivo experiments in mice provide evidence that the specific TRPM7 inhibitor waixenicin A, given as a single bolus injection, induces transient hypomagnesemia and increases intestinal absorption of calcium. Repeated injections of waixenicin A over 3 weeks cause hypomagnesemia via insufficient Mg2+ absorption by the colon. However, neither waixenicin A, nor a diet low in Mg2+, affect aberrant crypt foci development in an azoxymethane-induced colorectal cancer mouse model.

CONCLUSION

Early stage colon cancer proceeds independent of systemic Mg2+ status and TRPM7, and waixenicin A is a useful pharmacological tool to study of TRPM7 in vitro and in vivo.

Biodegradable Mg-Cu alloys with enhanced osteogenesis, angiogenesis, and long-lasting antibacterial effects

A series of biodegradable Mg-Cu alloys is designed to induce osteogenesis, stimulate angiogenesis, and provide long-lasting antibacterial performance at the same time. The Mg-Cu alloys with precipitated Mg2Cu intermetallic phases exhibit accelerated degradation in the physiological environment due to galvanic corrosion and the alkaline environment combined with Cu release endows the Mg-Cu alloys with prolonged antibacterial effects. In addition to no cytotoxicity towards HUVECs and MC3T3-E1 cells, the Mg-Cu alloys, particularly Mg-0.03Cu, enhance the cell viability, alkaline phosphatase activity, matrix mineralization, collagen secretion, osteogenesis-related gene and protein expressions of MC3T3-E1 cells, cell proliferation, migration, endothelial tubule forming, angiogenesis-related gene, and protein expressions of HUVECs compared to pure Mg. The favorable osteogenesis and angiogenesis are believed to arise from the release of bioactive Mg and Cu ions into the biological environment and the biodegradable Mg-Cu alloys with osteogenesis, angiogenesis, and long-term antibacterial ability are very promising in orthopedic applications.

Magnesium Modulates Doxorubicin Activity through Drug Lysosomal Sequestration and Trafficking

Magnesium is directly involved in the control of cell growth and survival, but its role in cancer biology and therapy is multifaceted; in particular, it is highly controversial whether magnesium levels can affect therapy outcomes. Here we investigated whether magnesium availability can modulate cellular responses to the widely used chemotherapeutic doxorubicin. We used an in vitro model consisting of mammary epithelial HC11 cells and found that high magnesium availability was correlated with diminished sensitivity both in cells chronically adapted to high magnesium concentrations and in acutely magnesium-supplemented cells. This decrease in sensitivity resulted from reduced intracellular doxorubicin accumulation in the face of a similar drug uptake rate. We observed that high-magnesium conditions caused a decrease in intracellular drug retention by altering drug lysosomal sequestration and trafficking. In our model, magnesium supplementation correspondingly modulated expression of the TRPM7 channel, which is known to control cytoskeletal organization and dynamics and may be involved in the proposed mechanism. Our findings suggest that magnesium supplementation in hypomagnesemic cancer patients may hinder response to therapy.

Preliminary fsLIBS study on bone tumors

The aim of this study is to evaluate the capability of femtosecond Laser Induced Breakdown Spectroscopy (fsLIBS) to discriminate between normal and cancerous bone, with implications to femtosecond laser surgery procedures. The main advantage of using femtosecond lasers for surgery is that the same laser that is being used to ablate can also be used for a feedback system to prevent ablation of certain tissues. For bone tumor removal, this technique has the potential to reduce the number of repeat surgeries that currently must be performed due to incomplete removal of the tumor mass. In this paper, we performed fsLIBS on primary bone tumor, secondary tumor in bone, and normal bone. These tissues were excised from consenting patients and processed through the UC Davis Cancer Center Biorepository. For comparison, each tumor sample had a matched normal bone sample. fsLIBS was performed to characterize the spectral signatures of each tissue type. A minimum of 20 spectra were acquired for each sample. We did not detect significant differences between the fsLIBS spectra of secondary bone tumors and their matched normal bone samples, likely due to the heterogeneous nature of secondary bone tumors, with normal and cancerous tissue intermingling. However, we did observe an increase in the fsLIBS magnesium peak intensity relative to the calcium peak intensity for the primary bone tumor samples compared to the normal bone samples. These results show the potential of using femtosecond lasers for both ablation and a real-time feedback control system for treatment of primary bone tumors.

Assessment of frequency and severity of hypomagnesemia in patients with metastatic colorectal cancer treated with cetuximab, with a review of the literature

Currently, there are a few systemic treatment options for patients with metastatic colorectal cancer (mCRC). Targeted therapy used in this setting includes the use of monoclonal antibodies, such as cetuximab or panitumumab, directed against epidermal growth factor receptor. The aim of the present study was to estimate the frequency and severity of hypomagnesemia among patients with mCRC treated with cetuximab. The data from the Department of Clinical Oncology, University Hospital of Krakow (Krakow, Poland), concerning 52 patients treated between 2009 and 2013 were collected. Of these, 27 patients fulfilled the inclusion criteria to enter this retrospective study. The National Cancer Institute Common Terminology Criteria for Adverse Events version 4.0 were used to grade the level of hypomagnesemia. In total, 29.6% of all patients experienced hypomagnesemia during treatment, and the majority of cases were grade 1 (22.2%). There was no statistically significant correlation between magnesium (Mg) level and patient age, duration of treatment, localization of primary tumor or metastases, and the number of metastases. However, there was an upward trend in a logistic regression model showing that the risk of developing hypomagnesemia increases with age. Hypomagnesemia is a frequent problem among mCRC patients receiving cetuximab. It is essential to introduce guidelines regarding the monitoring of the Mg level and its supplementation in this group of patients.

N-Myc-induced up-regulation of TRPM6/TRPM7 channels promotes neuroblastoma cell proliferation

Intracellular levels of the divalent cations Ca2+ and Mg2+ are important regulators of cell cycle and proliferation. However, the precise mechanisms by which they are regulated in cancer remain incompletely understood. The channel kinases TRPM6 and TRPM7 are gatekeepers of human Ca2+/Mg2+ metabolism. Here, we investigated the human neuroblastoma cell line SHEP-21N in which the MYCN oncogene (encoding N-Myc) can be reversibly expressed under control of an inducible repressor. We report that N-Myc expression increases cell growth and up-regulates both TRPM6 and TRPM7 expression. Membrane current analyses reveal that endogenous TRPM6/TRPM7 currents exhibit reduced Mg·ATP suppression, increased Mg2+ sensitivity, and diminished sensitivity to 2-APB inhibition. These properties are consistent with N-Myc-induced increase of heteromeric TRPM7/TRPM6 channels promoting Ca2+ and Mg2+ uptake. Genetic suppression of TRPM6/TRPM7 through siRNA inhibits cell proliferation, suggesting that N-Myc can promote neuroblastoma cell proliferation through up-regulation of divalent cation-transporting channels.

Downregulation of transient receptor potential M6 channels as a cause of hypermagnesiuric hypomagnesemia in obese type 2 diabetic rats

We assessed the expression profile of Mg2+-transporting molecules in obese diabetic rats as a cause of hypermagnesiuric hypomagnesemia, which is involved in the development of insulin resistance, hypertension, and coronary diseases. Kidneys were obtained from male Otsuka Long-Evans Tokushima fatty (OLETF) and Long-Evans Tokushima Otsuka (LETO) obese diabetic rats at the ages of 16, 24, and 34 wk. Expression profiles were studied by real-time PCR and immunohistochemistry together with measurements of urine Mg2+excretion. Urine Mg2+excretion was increased in 24-wk-old OLETF rats and hypomagnesemia was apparent in 34-wk-old OLETF rats but not in LETO rats (urine Mg2+excretion: 0.16 ± 0.01 μg·min−1·g body wt−1in 24-wk-old LETO rats and 0.28 ± 0.01 μg·min−1·g body wt−1in 24-wk-old OLETF rats). Gene expression of transient receptor potential (TRP)M6 was downregulated (85.5 ± 5.6% in 34-wk-old LETO rats and 63.0 ± 3.5% in 34-wk-old OLETF rats) concomitant with Na+-Cl−cotransporter downregulation, whereas the expression of claudin-16 in tight junctions of the thick ascending limb of Henle was not different. The results of the semiquantitative analysis of immunohistochemistry were consistent with these findings (TRPM6: 0.49 ± 0.04% in 16-wk-old LETO rats, 0.10 ± 0.01% in 16-wk-old OLETF rats, 0.52 ± 0.03% in 24-wk-old LETO rats, 0.10 ± 0.01% in 24-wk-old OLETF rats, 0.48 ± 0.02% in 34-wk-old LETO rats, and 0.12 ± 0.02% in 34-wk-old OLETF rats). Gene expression of fibrosis-related proinflammatory cytokines as well as histological changes showed that the hypermagnesiuria-related molecular changes and tubulointerstitial nephropathy developed independently. TRPM6, located principally in distal convoluted tubules, appears to be a susceptible molecule that causes hypermagnesiuric hypomagnesemia as a tubulointerstitial nephropathy-independent altered tubular function in diabetic nephropathy.

Magnesium protects against cisplatin-induced acute kidney injury without compromising cisplatin-mediated killing of an ovarian tumor xenograft in mice

Cisplatin, a commonly used chemotherapeutic for ovarian and other cancers, leads to hypomagnesemia in most patients and causes acute kidney injury (AKI) in 25-30% of patients. Previously, we showed that magnesium deficiency worsens cisplatin-induced AKI and magnesium replacement during cisplatin treatment protects against cisplatin-mediated AKI in non-tumor-bearing mice (Solanki MH, Chatterjee PK, Gupta M, Xue X, Plagov A, Metz MH, Mintz R, Singhal PC, Metz CN. Am J Physiol Renal Physiol 307: F369-F384, 2014). This study investigates the role of magnesium in cisplatin-induced AKI using a human ovarian tumor (A2780) xenograft model in mice and the effect of magnesium status on tumor growth and the chemotherapeutic efficacy of cisplatin in vivo. Tumor progression was unaffected by magnesium status in saline-treated mice. Cisplatin treatment reduced tumor growth in all mice, irrespective of magnesium status. In fact, cisplatin-treated magnesium-supplemented mice had reduced tumor growth after 3 wk compared with cisplatin-treated controls. While magnesium status did not interfere with tumor killing by cisplatin, it significantly affected renal function following cisplatin. Cisplatin-induced AKI was enhanced by magnesium deficiency, as evidenced by increased blood urea nitrogen, creatinine, and other markers of renal damage. This was accompanied by reduced renal mRNA expression of the cisplatin efflux transporter Abcc6. These effects were significantly reversed by magnesium replacement. On the contrary, magnesium status did not affect the mRNA expression of cisplatin uptake or efflux transporters by the tumors in vivo. Finally, magnesium deficiency enhanced platinum accumulation in the kidneys and renal epithelial cells, but not in the A2780 tumor cells. These findings demonstrate the renoprotective role of magnesium during cisplatin AKI, without compromising the chemotherapeutic efficacy of cisplatin in an ovarian tumor-bearing mouse model.

Expression of magnesium transporter genes in head and neck cancer patients underwent neoadjuvant cisplatin-based chemotherapy

We aimed to investigate expression of magnesium transporter genes in patients with head and neck cancer who underwent cisplatin-based neoadjuvant chemotherapy and their association with serum magnesium level. Head and neck cancer patients scheduled to undergo neoadjuvant cisplatin-based chemotherapy were eligible for enrollment. Blood samples were obtained at three time points: prior to, during, and after completion of chemotherapy. Expression levels of magnesium transporter genes were determined by quantitative real-time PCR. A total of 23 patients were included in the final analysis. The average serum magnesium levels dropped 6.98 and 5.20% during and after completion of chemotherapy. There were neither significant associations between serum magnesium level and demographic variables nor tumor-related variables. SLC41A1 expression level was positively correlated with serum magnesium whereas TRPM6 expression level was negatively correlated with serum magnesium. Serum magnesium level decreased during cisplatin-based chemotherapy in head and neck cancer patients. Further studies are warranted to investigate optimal magnesium measurement and substitution protocol.

Magnesium supplementation and high volume hydration reduce the renal toxicity caused by cisplatin-based chemotherapy in patients with lung cancer: a toxicity study

BACKGROUND

Renal toxicity is a clinical problem that affects 28-42% of patients undergoing treatment with cisplatin. Renal toxicity can be minimized by high volume hydration with mannitol diuresis. Recent reports have shown that cisplatin induces depletion of Mg and that Mg supplementation can reduce renal toxicity. We hypothesized that Mg infusion combined with low volume hydration may not be sufficient to overcome cisplatin-induced renal toxicity.

METHODS

In total, 85 patients with lung cancer receiving their first cycle of cisplatin-based chemotherapy at the Osaka City University Hospital were classified into three groups: those administered high volume hydration without Mg infusion (high-volume Mg-), high volume hydration with Mg infusion (high-volume Mg+), and with low volume hydration with Mg infusion (low-volume Mg+). Serum creatinine (sCr) and creatinine clearance (CrCl) were examined before and after treatment with cisplatin. Multivariable analysis was carried out to identify the most important contributing factors.

RESULTS

There were no significant differences in pre-treatment sCr levels or CrCl between groups. In the high-volume Mg- group, post-treatment sCr significantly increased compared with pre-treatment levels, while post-CrCl significantly decreased compared with pre-treatment CrCl (p < 0.001 and p < 0.001, respectively). In the high-volume Mg+ group, there was no significant difference between pre- and post-treatment levels of sCr, or between pre- and post-treatment CrCl (p = 0.118 and p = 0.254, respectively). In the low-volume Mg+ group, there was a trend towards increased sCr levels and decreased CrCl after treatment (p = 0.068 and p = 0.055, respectively). Multivariate analysis revealed that the absence of Mg infusion and low-volume hydration were both independent factors for decreased CrCl (p < 0.001 and p = 0.001, respectively).

CONCLUSIONS

High-volume hydration and Mg infusion reduces the renal toxicity induced by cisplatin. A low-volume Mg+ regimen may be considered for patients with adequate renal function.

TRIAL REGISTRATION

Observational Study UMIN000013950; Registered 13 May 2014.

Magnesium protects against cisplatin-induced acute kidney injury by regulating platinum accumulation

Despite its success as a potent antineoplastic agent, ∼25% of patients receiving cisplatin experience acute kidney injury (AKI) and must discontinue therapy. Impaired magnesium homeostasis has been linked to cisplatin-mediated AKI, and because magnesium deficiency is widespread, we examined the effect of magnesium deficiency and replacement on cisplatin-induced AKI in physiologically relevant older female mice. Magnesium deficiency significantly increased cisplatin-associated weight loss and markers of renal damage (plasma blood urea nitrogen and creatinine), histological changes, inflammation, and renal cell apoptosis and modulated signaling pathways (e.g., ERK1/2, p53, and STAT3). Conversely, these damaging effects were reversed by magnesium. Magnesium deficiency alone significantly induced basal and cisplatin-mediated oxidative stress, whereas magnesium replacement attenuated these effects. Similar results were observed using cisplatin-treated LLC-PK1 renal epithelial cells exposed to various magnesium concentrations. Magnesium deficiency significantly amplified renal platinum accumulation, whereas magnesium replacement blocked the augmented platinum accumulation after magnesium deficiency. Increased renal platinum accumulation during magnesium deficiency was accompanied by reduced renal efflux transporter expression, which was reversed by magnesium replacement. These findings demonstrate the role of magnesium in regulating cisplatin-induced AKI by enhancing oxidative stress and thus promoting cisplatin-mediated damage. Additional in vitro experiments using ovarian, breast, and lung cancer cell lines showed that magnesium supplementation did not compromise cisplatin's chemotherapeutic efficacy. Finally, because no consistently successful therapy to prevent or treat cisplatin-mediated AKI is available for humans, these results support developing more conservative magnesium replacement guidelines for reducing cisplatin-induced AKI in cancer patients at risk for magnesium deficiency.

Do fasudil and Y-27632 affect the level of transient receptor potential (TRP) gene expressions in breast cancer cell lines?

Breast cancer (BC) is the most frequent cancer type in women, and the mortality rate is high especially in metastatic disease. Ion channels such as the transient receptor potential (TRP) channels correlate with malignant growth and cancer progression. Hence, some authors have suggested that the expression levels of TRP channels may be used as a marker in the diagnosis and predicting the prognosis of BC. Also, in some recent studies, targeting TRP channels are suggested as a novel treatment strategy in BC. The aim of this study was to investigate the effect of two Rho-kinase (ROCK) inhibitors, fasudil and Y-27632, on the expression levels of TRP channel genes in breast cancer cell lines (ZR-75-1, MCF7, and MDA-MB-231) and breast epithelial cell line (hTERT-HME1). The expression levels of TRP genes were determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR). We found that fasudil had reduced the TRPC1, TRPV2 expression levels in the ZR-75-1, MCF7, and MDA-MB-231 cell lines. On the other hand, fasudil and Y-27632 had reduced TRPM6 expression levels in all cell lines. Y-27632 increased the expression levels of TRPC7 in all cell lines. In conclusion, this is the first study demonstrating that the inhibition of ROCK pathway changes the expression levels of some TRP genes. Also, our study has firstly shown that the expression levels of the TRP genes which are suggested as a diagnostic and prognostic biomarker in BC, were changed with the treatment of fasudil and Y-27632.

Protective effect of magnesium preloading on cisplatin-induced nephrotoxicity: a retrospective study

OBJECTIVE

Magnesium supplementation has been reported to have a nephroprotective effect on cisplatin-induced renal dysfunction, but little evidence exists regarding the effect of magnesium preloading before cisplatin administration. We started to include magnesium preloading (8 mEq) in cisplatin-containing treatment regimens in January 2011. The aim of the present study was to evaluate whether magnesium preloading reduces cisplatin-induced nephrotoxicity.

METHODS

We retrospectively reviewed 496 thoracic malignancy patients treated with cisplatin (≥60 mg/m²)-containing regimens as a first-time chemotherapy between January 2009 and December 2011. We compared the incidence of Grade ≥2 serum creatinine elevation according to the Common Terminology Criteria for Adverse Events, version 4.0, between magnesium preloading group (n = 161 [32%]) and non-magnesium preloading group (n = 335 [68%]) during the first cycle and all cycles.

RESULTS

The median number of administered cycles was four in both groups. The incidence of Grade ≥2 serum creatinine elevation in magnesium preloading group was significantly lower during both the first cycle and all cycles than in the non-magnesium preloading group (4.9 versus 19.1% during the first cycle, and 14.2 versus 39.7% during all the cycles). A multivariate analysis indicated that magnesium preloading significantly reduced cisplatin-induced nephrotoxicity throughout the entire period from after the first administration (odds ratio: 0.262, 95% confidence interval: 0.106-0.596 during the first cycle, and odds ratio: 0.234, 95% confidence interval: 0.129-0.414 during all cycles).

CONCLUSIONS

Magnesium preloading before cisplatin administration significantly reduced cisplatin-induced nephrotoxicity.

Elevated plasma magnesium and calcium may be associated with shorter telomeres in older South Australian women

Telomeres are structures that cap the ends of chromosomes. The integrity of the telomere structure and its DNA hexamer (TTAGGG)n repeat sequence is critical for protecting the ends of chromosomes from degradation and in maintaining overall chromosomal stability. Currently, there are limited data on the influence that nutrition has on telomere length. Recent studies have suggested that micronutrients may influence telomere length. Here we examined the relationship between telomere length in lymphocytes and plasma calcium, magnesium, selenium and zinc status in a healthy cohort of younger and older adults. We report a negative association between telomere length and both plasma calcium and magnesium levels, (r=-0.47, P=0.03 and r=-0.61, P=0.001 respectively), in older females; Intriguingly Ca/Mg ratio was positively associated with telomere length (r=0.55, P=0.007). These relationships were not observed in the younger adults, nor in the older males. In conclusion, our study provides preliminary evidence suggesting that levels of plasma magnesium and calcium may impact on telomere length in lymphocytes in older women.

Hydration with magnesium and mannitol without furosemide prevents the nephrotoxicity induced by cisplatin and pemetrexed in patients with advanced non-small cell lung cancer

BACKGROUND

The aim of this study was to examine the effect of hydration with magnesium and mannitol without furosemide on the nephrotoxocity accompanying combination chemotherapy using cisplatin and pemetrexed in patients with advanced non-small cell lung cancer (NSCLC).

METHODS

Fifty patients with NSCLC who received cisplatin plus pemetrexed, using either old hydration protocol including normal saline with mannitol and furosemide, or a new one including normal saline with magnesium and mannitol without furosemide were retrospectively analyzed. Nephrotoxicity was compared between patients treated using the old protocol and those treated with the new protocol. Univariate and multivariate analyses were performed to identify the independent factors associated with protection against nephrotoxicity in patients with NSCLC who received cisplatin plus pemetrexed.

RESULTS

Thirty patients received the old hydration protocol, while 20 patients were treated using the new hydration protocol. The patients treated using the new hydration protocol showed a significantly greater increase in creatinine clearance (P=0.0004) and a decrease in the serum creatinine level (P=0.0148) after one course of chemotherapy compared with those treated using the old hydration protocol. There were no differences in the chemotherapeutic response or overall survival between the groups (P=0.572). The new hydration protocol with supplemented magnesium with mannitol without furosemide was an independent factor for the protection against nephrotoxicity induced by cisplatin and pemetrexed in patients with advanced NSCLC [HR 0.232 (95% CI: 0.055-0.986), P=0.039].

CONCLUSIONS

These results demonstrate that the new hydration protocol comprising supplementation with magnesium without furosemide could prevent the nephrotoxicity induced by cisplatin and pemetrexed without affecting the treatment outcome.

Crown Ether Host-Rotaxanes as Cytotoxic Agents

Highly toxic bacterial ionophores are commonly used in veterinary medicine, but their therapeutic index is too narrow for human usage. With the goal of developing ionophores with a broader therapeutic index, we constructed highly derivatized synthetic ionophores. The toxicities of crown ether host-rotaxanes (CEHR's) against the SKOV-3 cell line were measured. The effect of Mg²⁺ or Ca²⁺ on toxicity was explored because changes in the intracellular concentration of these cations can cause cell death through apoptosis. We found Boc-CEHR is highly toxic and Arg-CEHR is slightly less toxic with IC₅₀ values of 0.5 μM and 6 μM, respectively, in standard growth medium. Increasing the concentration of Ca²⁺ resulted in greater toxicity of the CEHRs, whereas increasing the concentration of Mg²⁺ was less effective on reducing IC₅₀. Cell death occurs mainly through apoptosis. Although preliminary, these results suggest that the CEHRs deliver Ca²⁺ and perhaps Mg²⁺ into cells inducing apoptosis.

Association of hypomagnesemia with inferior survival in a phase III, randomized study of cetuximab plus best supportive care versus best supportive care alone: NCIC CTG/AGITG CO.17

BACKGROUND

Cetuximab-induced hypomagnesemia has been associated with improved clinical outcomes in advanced colorectal cancer (CRC). We explored this relationship from a randomized clinical trial of cetuximab plus best supportive care (BSC) versus BSC alone in patients with pretreated advanced CRC.

PATIENTS AND METHODS

Day 28 hypomagnesemia grade (0 versus ≥1) and percent reduction (<20% versus ≥20%) of Mg from baseline was correlated with outcome.

RESULTS

The median percentage Mg reduction at day 28 was 10% (-42.4% to 63.0%) for cetuximab (N = 260) versus 0% (-21.1% to 25%) for BSC (N = 251) [P < 0.0001]. Grade ≥1 hypomagnesemia and ≥20% reduction from baseline at day 28 were associated with worse overall survival (OS) [hazard ratio, HR 1.61 (95% CI 1.12-2.33), P = 0.01 and 2.08 (95% CI 1.32-3.29), P = 0.002, respectively] in multivariate analysis including grade of rash (0-1 versus 2+). Dyspnea (grade ≥3) was more common in patients with ≥20% versus < 20% Mg reduction (68% versus 45%; P = 0.02) and grade 3/4 anorexia were higher in patients with grade ≥1 hypomagnesemia (81% versus 63%; P = 0.02).

CONCLUSIONS

In contrast to prior reports, cetuximab-induced hypomagnesemia was associated with poor OS, even after adjustment for grade of rash.

Cetuximab-induced hypomagnesaemia aggravates peripheral sensory neurotoxicity caused by oxaliplatin

Calcium and magnesium replacement is effective in reducing oxaliplatin-induced neurotoxicity. However, cetuximab treatment has been associated with severe hypomagnesaemia. Therefore, we retrospectively investigated whether cetuximab-induced hypomagnesaemia exacerbated oxaliplatin-induced neurotoxicity. Six patients with metastatic colorectal cancer who were previously treated with oxaliplatin-fluorouracil combination therapy were administered cetuximab in combination with irinotecan alone or irinotecan and fluorouracil as a second-line treatment. All patients had normal magnesium levels before receiving cetuximab. The Common Terminology Criteria for Adverse Events version 3.0 was used to evaluate the grade of neurotoxicity, hypomagnesaemia, hypocalcaemia, and hypokalemia every week. All six patients had grade 1 or higher hypomagnesaemia after starting cetuximab therapy. The serum calcium and potassium levels were within the normal range at the onset of hypomagnesaemia. Oxaliplatin-induced neurotoxicity occurred in all patients at the beginning of cetuximab therapy, with grade 1 neurotoxicity in five patients and grade 2 in one patient. After cetuximab administration, the neurotoxicity worsened in all six patients, and three progressed to grade 3. Among the three patients with grade 3 neurotoxicity, two required a dose reduction and one had to discontinue cetuximab therapy. A discontinuation or dose reduction in cetuximab therapy was associated with exacerbated oxaliplatin-induced neurotoxicity due to cetuximab-induced hypomagnesaemia in half of patients who had previously received oxaliplatin. Therefore, when administering cetuximab after oxaliplatin therapy, we suggest serially evaluating serum magnesium levels and neurotoxicity.

Magnesium and its transporters in cancer: a novel paradigm in tumour development

The relationship between magnesium and cancer is not as simple as could be assumed from the well-established requirement of magnesium for cell proliferation. Basic and pre-clinical studies indicate that magnesium deficiency can have both anti- and pro-tumour effects. In the present review, we briefly outline the new findings on the role of magnesium in angiogenesis and metastatization, and focus on the relationship between tumour cell proliferation and metabolic reprogramming, discussing how magnesium and its transporters are involved in these processes. The role of magnesium in cancer is also critically examined with regard to mitochondrial function, apoptosis and resistance to treatment. Finally, we bring together the latest experimental evidence indicating that alteration in the expression and/or activity of magnesium channels is a frequent finding in cancer cells and human tumour tissues examined to date, and we discuss the potential implications for developing novel diagnostic and therapeutic strategies.

Silencing TRPM7 mimics the effects of magnesium deficiency in human microvascular endothelial cells

Evidence has accumulated to suggest that magnesium might play a role in controlling angiogenesis. Since microvascular endothelial cells are protagonists in this process, we investigated the behavior of these cells cultured in low extracellular magnesium or silenced for its transporter Transient Receptor Potential Melastatin (TRPM)7, essential for cellular magnesium homeostasis. In particular, we focused on some crucial steps of the angiogenic process, i.e. proliferation, migration, protease production and organization in tridimensional structures. Silencing TRPM7 mimics the effects of low extracellular magnesium on human microvascular endothelial cells (HMEC). Indeed, while no effects were observed on the production of metalloproteases and on tridimensional organization on matrigel, both magnesium deficiency and silencing of TRPM7 impair cell migration and inhibit growth by arresting the cells in the G0/G1 and G2/M phases of the cell cycle. Since low extracellular magnesium markedly decreases TRPM7 in HMEC, we suggest that TRPM7 downregulation might mediate low magnesium-induced inhibition of cell growth and migration. Human endothelial cells from the umbilical vein are growth inhibited by low magnesium and growth stimulated after TRPM7 silencing. An impairment of ERK phosphorylation in HMEC silencing TRPM7 is responsible, in part, for the different proliferative behavior of these two cell types. We broadened our studies also to endothelial colony-forming cells and found that they are sensitive to fluctuations of the concentrations of extracellular magnesium, while their proliferation rate is not modulated by TRPM7 silencing. Our results point to magnesium and TRPM7 as a modulators of the angiogenic phenotype of microvascular endothelial cells.

Waixenicin A inhibits cell proliferation through magnesium-dependent block of transient receptor potential melastatin 7 (TRPM7) channels

Transient receptor potential melastatin 7 (TRPM7) channels represent the major magnesium-uptake mechanism in mammalian cells and are key regulators of cell growth and proliferation. They are expressed abundantly in a variety of human carcinoma cells controlling survival, growth, and migration. These characteristics are the basis for recent interest in the channel as a target for cancer therapeutics. We screened a chemical library of marine organism-derived extracts and identified waixenicin A from the soft coral Sarcothelia edmondsoni as a strong inhibitor of overexpressed and native TRPM7. Waixenicin A activity was cytosolic and potentiated by intracellular free magnesium (Mg(2+)) concentration. Mutating a Mg(2+) binding site on the TRPM7 kinase domain reduced the potency of the compound, whereas kinase deletion enhanced its efficacy independent of Mg(2+). Waixenicin A failed to inhibit the closely homologous TRPM6 channel and did not significantly affect TRPM2, TRPM4, and Ca(2+) release-activated Ca(2+) current channels. Therefore, waixenicin A represents the first potent and relatively specific inhibitor of TRPM7 ion channels. Consistent with TRPM7 inhibition, the compound blocked cell proliferation in human Jurkat T-cells and rat basophilic leukemia cells. Based on the ability of the compound to inhibit cell proliferation through Mg(2+)-dependent block of TRPM7, waixenicin A, or structural analogs may have cancer-specific therapeutic potential, particularly because certain cancers accumulate cytosolic Mg(2+).

Elemental fingerprinting of tumorous and adjacent non-tumorous tissues from patients with colorectal cancer using ICP-MS, ICP-OES and chemometric analysis

Tumorous and adjacent non-tumorous paired biopsies from 38 patients with colorectal cancer were analyzed by inductively coupled plasma mass spectrometry and inductively coupled plasma optical emission spectrometry after low-volume microwave digestion. 18 elements were investigated: Ag, Al, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Ni, P, Pb, S, Se and Zn. Different chemometric tools were used for data evaluation: Wilcoxon signed rank test, Hieratical clustering analysis, principal component analysis (PCA) and linear discriminant analysis (LDA). With the exception of Al, tumours were observed to have significantly more elevated concentrations of essential elements as compared to non-tumours. On the contrary, elements considered potentially carcinogenic such as Cr, Ni, Mo or Co do not display significant differences. When PCA was applied, different components were obtained for tumorous and non-tumorous tissues. When LDA was applied for the elements studied (including essential and non-essential elements) about 90% of cases were correctly classified.

Cellular magnesium homeostasis

Magnesium, the second most abundant cellular cation after potassium, is essential to regulate numerous cellular functions and enzymes, including ion channels, metabolic cycles, and signaling pathways, as attested by more than 1000 entries in the literature. Despite significant recent progress, however, our understanding of how cells regulate Mg(2+) homeostasis and transport still remains incomplete. For example, the occurrence of major fluxes of Mg(2+) in either direction across the plasma membrane of mammalian cells following metabolic or hormonal stimuli has been extensively documented. Yet, the mechanisms ultimately responsible for magnesium extrusion across the cell membrane have not been cloned. Even less is known about the regulation in cellular organelles. The present review is aimed at providing the reader with a comprehensive and up-to-date understanding of the mechanisms enacted by eukaryotic cells to regulate cellular Mg(2+) homeostasis and how these mechanisms are altered under specific pathological conditions.

[Cutaneous toxicity associated with cetuximab treatment in metastatic colorectal cancer]

OBJECTIVE

To evaluate the impact and type of side-effects in patients treated with cetuximab and provide a description of the general measures and treatment.

METHODS

Retrospective safety study. We included all patients that received cetuximab from January to December 2009. All information was obtained from the Pharmacy and Oncology Department's Access databases and reviewed the patient's medical history. All data was registered in an Excel workbook. Skin toxicity was graded by the current National Cancer Institute-Common Toxicity Criteria (NCI-CTC).

RESULTS

During the study period 43 patients received treatment with cetuximab. Acneiform eruption was present in 30 of the cases (69.8%): 14 patients with grade 1 (48.3%), 13 with grade 2 (44.8%) and 3 with grade 3 (10.3%). These adverse effects appeared in a median of seven (4-28) days. In a median of 40 (20-56) days, ten patients (23.3%) presented xerosis, and three (7%) suffered painful fissures in hands and feet after a median of 28 (21-35) days. Paronychia was present in two patients after a median of 42 (35-49) days. Finally, an alteration in hair growth was observed in two patients with overgrowth of facial hair and one patient with overgrowth of the eyelashes. Five patients presented important conjunctivitis. Three infusion reactions occurred. A grade-based treatment algorithm was used for all patients that presented cutaneous toxicity.

CONCLUSIONS

A considerable number of patients treated with cetuximab develop dermatological side-effects which left untreated could represent a threat to the efficacy of the therapy. Therefore effective management is mandatory, patient education and immediate treatment based on a grade-based algorithm to alleviate symptoms is necessary, so that patient compliance is guaranteed.