Effect of folic acid and vitamin B12 on pemetrexed antifolate chemotherapy in nutrient lung cancer cells

The response of gut microbiota to arsenic metabolism is involved in arsenic-induced liver injury, which is influenced by the interaction between arsenic and methionine synthase

The drivers of changes in gut microbiota under arsenic exposure and the mechanism by which microbiota affect arsenic metabolism are still unclear. Here, C57BL/6 mice were exposed to 0, 5, or 10 ppm NaAsO2 in drinking water for 6 months. The results showed that arsenic exposure induced liver injury and increased the abundance of folic acid (FA)/vitamin B12 (VB12)- and butyrate-synthesizing microbiota. Statistical analysis and in vitro cultures showed that microbiota were altered to meet the demand for FA/VB12 by arsenic metabolism and to resist the toxicity of unmetabolized arsenic. However, at higher arsenic levels, changes of these microbiota were inconsistent. A 3D molecular simulation showed that arsenic bound to methionine synthase (MTR), which was confirmed by SEC-UV-DAD (1 μM recombinant human MTR was purified with 0 or 2 μM NaAsO2 at room temperature for 1 h) and fluorescence-labeled arsenic co-localization (primary hepatocytes were exposed to 0, 0.5, or 1 μM ReAsH-EDT2 for 24 h) in non-cellular and cellular systems. Mechanistically, the arsenic-MTR interaction in the liver interferes with the utilization of FA/VB12, which increases arsenic retention and thus results in a substantial increase in the abundance of butyrate-synthesizing microbiota compared to FA/VB12-synthesizing microbiota. By exposing C57BL/6J mice to 0 or 10 ppm NaAsO2 with or without FA (6 mg/L) and VB12 (50 μg/L) supplementation in their drinking water for 6 months, we constructed an FA/VB12 intervention mouse model and found that FA/VB12 supplementation blocked the disturbance of gut microbiota, restored MTR levels, promoted arsenic metabolism, and alleviated liver injury. We demonstrate that the change of gut microbiota is a response to arsenic metabolism, a process influenced by the arsenic-MTR interaction. This study provides new insights for understanding the relationship between gut microbiota and arsenic metabolism and present therapeutic targets for arseniasis.

Schedule-Dependent Treatment Increases Chemotherapy Efficacy in Malignant Pleural Mesothelioma

Malignant pleural mesothelioma (MPM) is a rare but aggressive thoracic malignancy with limited treatment options. One of the standard treatments for MPM is chemotherapy, which consists of concurrent treatment with pemetrexed and cisplatin. Pemetrexed limits tumor growth by inhibiting critical metabolic enzymes involved in nucleotide synthesis. Cisplatin causes direct DNA damage, such as intra-strand and inter-strand cross-links, which are repaired by the nucleotide excision repair pathway, which depends on relatively high nucleotide levels. We hypothesized that prolonged pretreatment with pemetrexed might deplete nucleotide pools, thereby sensitizing cancer cells to subsequent cisplatin treatment. The MPM cell lines ACC-MESO-1 and NCI-H28 were treated for 72 h with pemetrexed. Three treatment schedules were evaluated by initiating 24 h of cisplatin treatment at 0 h (concomitant), 24 h, and 48 h relative to pemetrexed treatment, resulting in either concomitant administration or pemetrexed pretreatment for 24 h or 48 h, respectively. Multicolor flow cytometry was performed to detect γH2AX (phosphorylation of histone H2AX), a surrogate marker for the activation of the DNA damage response pathway. DAPI staining of DNA was used to analyze cell cycle distribution. Forward and side scatter intensity was used to distinguish subpopulations based on cellular size and granularity, respectively. Our study revealed that prolonged pemetrexed pretreatment for 48 h prior to cisplatin significantly reduced long-term cell growth. Specifically, pretreatment for 48 h with pemetrexed induced a cell cycle arrest, mainly in the G2/M phase, accumulation of persistent DNA damage, and induction of a senescence phenotype. The present study demonstrates that optimizing the treatment schedule by pretreatment with pemetrexed increases the efficacy of the pemetrexed-cisplatin combination therapy in MPM. We show that the observed benefits are associated with the persistence of treatment-induced DNA damage. Our study suggests that an adjustment of the treatment schedule could improve the efficacy of the standard chemotherapy regimen for MPM and might improve patient outcomes.

Correlation between MTHFR 677C > T polymorphism and response of pemetrexed-based chemotherapy in advanced NSCLC: A meta-analysis

Objective

The aim of this study was to investigate the correlation between MTHFR 677C > T polymorphism and response of pemetrexed-based chemotherapy in advanced non-small-cell lung cancer (NSCLC) by pooling the open published relevant studies.

Methods

Clinical studies associated with MTHFR 677C > T polymorphism and response of pemetrexed-based chemotherapy in advanced NSCLC were systematically searched in databases of Pubmed, Embase, Cochrance Library, China national knowledge infrastructure (CNKI) and Wanfang. The correlation was expressed by odds ratio (OR) and corresponding 95% confidence interval (95% CI). The publication bias of the included studies was evaluated through Begg’s funnel plot and Egger’s line regression test.

Results

Ten prospective clinical studies relevant to MTHFR 677C > T polymorphism and response of pemetrexed-based chemotherapy in NSCLC were included in the present meta-analysis. The pooled results indicated that the partial response in NSCLC patients with TT or CT genotype was inferior to CC genotype in a dominant gene model (TT + CT vs CC) (OR = 0.16, 95% CI: 0.06–0.41, P = 0.001). NSCLC cases with T genotype were inferior to C genotype in the objective response rate treated with pemetrexed-based chemotherapy for dominant (OR = 0.28, 95% CI: 0.18–0.45, P = 0.001), recessive (OR = 0.43, 95% CI: 0.19–0.94, P = 0.03) and homozygous models (OR = 0.30, 95% CI: 0.13–0.67, P = 0.003). However, there was no statistical difference in disease control rate, progressive disease between different genotypes of different gene models (P all > 0.05).

Conclusion

The pemetrexed-based chemotherapy response was decreased in NSCLC cases with T genotype, which can be applied as a potential pemetrexed-based chemotherapy response marker.

Methyl-Donors Can Induce Apoptosis and Attenuate Both the Akt and the Erk1/2 Mediated Proliferation Pathways in Breast and Lung Cancer Cell Lines

Dietary methyl-donors play important roles in physiological processes catalyzed by B vitamins as coenzymes, and are used for complementary support in oncotherapy. Our hypothesis was that methyl-donors can not only assist in tolerating cancer treatment but may also directly interfere with tumor growth and proliferation. Therefore, we investigated the proposed cancer inhibitory effects of methyl-donors (in a mixture of L-methionine, choline chloride, folic acid, and vitamin B12) on MCF7 and T47D breast cancer as well as A549 and H1650 lung cancer cell lines. Indeed, methyl-donor treatment significantly reduced the proliferation in all cell lines, possibly through the downregulation of MAPK/ERK and AKT signaling. These were accompanied by the upregulation of the pro-apoptotic Bak and Bax, both in MCF7 and H1650 cells, at reduced anti-apoptotic Mcl-1 and Bcl-2 levels in MCF7 and H1650 cells, respectively. The treatment-induced downregulation of p-p53(Thr55) was likely to contribute to protecting the nuclear localization and apoptosis inducing functions of p53. The presented features are known to improve the sensitivity of cancer therapy. Therefore, these data support the hypothesis, i.e., that methyl-donors may promote apoptotic signaling by protecting p53 functions through downregulating both the MAPK/ERK and the AKT pathways both in breast and lung adenocarcinoma cell lines. Our results can emphasize the importance and benefits of the appropriate dietary supports in cancer treatments. However, further studies are required to confirm these effects without any adverse outcome in clinical settings.

Antitumor activity of sitagliptin and vitamin B12 on Ehrlich ascites carcinoma solid tumor in mice

This study was carried out to investigate the potential effects of vitamin B12 and sitagliptin, and their possible synergistic effect with doxorubicin (DOX) on the Ehrlich solid tumor model. B12, sitagliptin, and their combination with DOX were administered to tumor-bearing mice for 21 days. Treatment with B12, sitagliptin, as well as their combinations with DOX caused a significant inhibition of tumor growth and increased the survival time. Malondialdehyde levels and the relative expression of tumor necrosis factor-α and nuclear factor kappa B were significantly decreased, whereas the total antioxidant capacity was significantly increased in all treated groups, except the DOX-treated one, when compared with the positive control group. Moreover, increased apoptosis was also observed by increased cleaved caspase-3 immunostaining and histopathological examination. In conclusion, the antitumor activity of B12 and sitagliptin could be attributed to their ability to induce apoptosis and suppress oxidative stress and inflammation.

Comparison of ESI-MS/MS and APCI-MS methods for the quantification of folic acid analogs in C. elegans

Folic acid (FA) plays a vital role in central metabolism, including the one carbon cycle, nucleotide, and amino acid biosynthesis. The development of sensitive, accurate analytical methods to measure FA intermediates in tissues is critical to understand their biological roles in diverse physiological and pathological contexts. Here, we developed a highly sensitive method for the simultaneous quantification of FA intermediates in the nematode Caenorhabditis elegans as a model to dissect metabolic networks. The method was further validated by analyzing the worm folate pool upon RNAi knockdown of the dihydrofolate reductase gene dhfr-1. Comparative mass spectrometry behavior of the FA analogs using two different ion sources, electrospray ionization (ESI) and atmospheric pressure chemical ionization (APCI), revealed ESI-MS/MS to be more sensitive, but APCI-MS provided more detailed structure inferences, which can elucidate chemical investigation and synthesis of FA analogs. Finally, we report on the use of in vitro oxidation coupled with high-resolution mass spectrometry as a tool to discover new endogenous FA derivatives in the nematode.

Systemic anticancer therapy (SACT) for lung cancer and its potential for interactions with other medicines

Background

Systemic anticancer therapy, comprising chemotherapy agents alongside targeted therapies and immunotherapy, is clinically indicated for late-stage lung cancer. It is delivered in regimens often containing multiple anticancer agents as well as supportive care medicines to reduce side effects, raising potential for polypharmacy and therefore the possibility of drug–drug interactions with medicines taken for comorbidities. A pharmacy-led process commonly performed to assist safe prescribing in secondary care is medicines reconciliation; its benefit in minimising interactions involving systemic anticancer therapy medicines has not been assessed previously.

Objectives

The objectives were to characterise the potential drug–drug interactions between systemic anticancer therapy medicines for lung cancer and other medicines and to evaluate the rate of medicines reconciliation being performed and the extent of documentation of potential interactions (clinical audit).

Methodology

This retrospective case series study involved recording the medicines being taken by lung cancer patients undergoing systemic anticancer therapy elicited in consultations at Chelsea and Westminster Hospital, United Kingdom. Potential interactions were identified and characterised in terms of severity using the British National Formulary and other sources. Patient consultation records were also searched for documentation of medicines reconciliation and acknowledgement of potential drug–drug interactions.

Results

Twenty-three patients were included in this study. Eighty-eight potential drug–drug interactions were identified across 21 patients, 39% (34/88) of which involved the supportive care medicine dexamethasone. 3.0% of consultations included a documented medicines reconciliation, and 15.9% of potential interactions were documented in the notes, with no correlation between the two. Potentially serious interactions were significantly more likely to be documented (p < 0.05).

Conclusions

Many potential drug–drug interactions involving anticancer agents and supportive care medicines exist; particular attention should be paid to dexamethasone. Documentation of interactions and medicines reconciliation occur much less often than expected, suggesting there is scope for implementing methods of safe prescribing to prevent adverse drug effects.

Reduced folate and serum vitamin metabolites in patients with rectal carcinoma: an open-label feasibility study of pemetrexed with folic acid and vitamin B12 supplementation

The objectives of this single-center, open-label, phase II study were to evaluate (a) the feasibility and safety of neoadjuvant administration of pemetrexed with oral folic acid and vitamin B₁₂ (FA/B₁₂) in newly diagnosed patients with resectable rectal cancer and (b) intracellular and systemic vitamin metabolism. Patients were treated with three cycles of pemetrexed (500 mg/m², every 3 weeks) and FA/B₁₂ before surgery. The reduced folates tetrahydrofolate, 5-methyltetrahydrofolate, and 5,10-methylenetetrahydrofolate were evaluated from biopsies in tumor tissue and in adjacent mucosa. Serum levels of homocysteine, cystathionine, and methylmalonic acid were also measured. All 37 patients received three cycles of pemetrexed; 89.2% completed their planned dosage within a 9-week feasibility time frame. Neither dose reductions nor study drug-related serious adverse events were reported. Reduced folate levels were significantly higher in tumor tissue compared with adjacent mucosa at baseline. After FA/B₁₂ administration, tissue levels of reduced folates increased significantly and remained high during treatment in both tumor and mucosa until surgery. Serum levels of cystathionine increased significantly compared with baseline after FA/B₁₂ administration, but then decreased, fluctuating cyclically during pemetrexed therapy. Homocysteine and methylmalonic acid levels decreased significantly after FA/B₁₂ administration, and remained below baseline levels during the study. These results indicate that administration of three neoadjuvant cycles of single-agent pemetrexed, every 3 weeks, with FA/B₁₂ in patients with resectable rectal cancer is feasible and tolerable. Tissue and serum vitamin metabolism results demonstrate the influence of pemetrexed and FA/B₁₂ on vitamin metabolism and warrant further study.

Efficacies and adverse reactions of modified vitamin supplement programs before pemetrexed chemotherapy as a second-line treatment against epidermal growth factor receptor (EGFR) mutant wild-type lung adenocarcinoma

OBJECTIVE

This study aims to observe the efficacies and adverse reactions of modified vitamin programs before pemetrexed chemotherapy (second-line treatment) against epidermal growth factor receptor (EGFR) mutant wild-type lung adenocarcinoma.

METHODS

477 patients with IIIB, phase IV glomerular filtration rate (GFR) mutant-negative lung adenocarcinomas and performed pemetrexed chemotherapy were collected and divided into group A (167 cases, with modified program) and group B (310 cases, with traditional program). The modified program was: orally administrated 400 μg folic acid once per day and 1 day before the first-round pemetrexed chemotherapy, until the 21st day of the final administration of pemetrexed, and intramuscularly injected 500 μg vitamin B12 1 day before the first-round pemetrexed chemotherapy, and injected once 1 day before every round pemetrexed treatment.

RESULTS

Comparison between group A and group B: mean chemotherapy cycles (4.08 vs 3.98); effectiveness rate (22.16% vs 22.90%); disease control rate (56.51% vs 55.00%); without significant difference (P > 0.05). Two groups currently all reached the median overall survival (OS). The median progression-free survival (PFS): 4.2 vs 4.1 months; OS: 12.9 vs 13.2 months, without statistical difference (P > 0.05). Such side effects between the two groups as leukopenia, neutropenia, thrombocytopenia, anemia, nausea, vomiting, diarrhea, fatigue, creatinine increasing, alanine transaminase (ALT) increasing, stomatitis, peripheral neuropathy, alopecia and rash had no significant difference (P > 0.05).

CONCLUSIONS

The modified vitamin supportive treatment could ensure the efficacy, significantly simplify, facilitate the clinical application, and increase the associated toxicities, indicating that the pemetrexed-based chemotherapy did not need to be delayed because applying the vitamin supportive treatment.

Phase 1 dose de-escalation trial of the endogenous folate [6R]-5,10-methylene tetrahydrofolate in combination with fixed-dose pemetrexed as neoadjuvant therapy in patients with resectable rectal cancer

Background Modufolin® ([6R]-5,10-methylene tetrahydrofolate; [6R]-MTHF) is an endogenous biomodulator that is being developed as an alternative to leucovorin, a folate prodrug used in the treatment of colorectal cancer. The objective of this phase 1 dose de-escalation trial was to estimate the minimum tolerated dose of [6R]-MTHF to be used in combination with pemetrexed 500 mg/m² in the neoadjuvant treatment of patients with rectal cancer. Methods Adult patients (≥18 years) with resectable rectal adenocarcinoma were allocated to [6R]-MTHF doses of 500, 100, 50, and 10 mg/m² in combination with pemetrexed 500 mg/m². [6R]-MTHF was administered as an intravenous (i.v.) bolus injection 1 week prior to the first dose of pemetrexed and then once weekly for 9 weeks; pemetrexed was administered by i.v. infusion once every 21 days for three cycles. Results Twenty-four patients (mean [SD] age, 63.1 [12.9] years) were enrolled in the study. A total of 72 treatment-related adverse events (AEs) were reported, of which the most common were fatigue (n = 17; 23.6 %), nausea (n = 10; 13.9 %), and diarrhea (n = 5; 6.9 %). The incidence of treatment-related AEs by [6R]-MTHF dose level (500, 100, 50, 10 mg/m²) was 11.1 % (n = 8), 13.9 % (n = 10), 45.8 % (n = 33), and 29.2 % (n = 21), respectively. There were no dose-limiting toxicities, and only two (2.8 %) treatment-related AEs were grade 3 in severity. Of the 11 serious AEs reported, none were considered to be related to [6R]-MTHF treatment. Conclusions The results of this phase 1 study indicate that the estimated minimum tolerated dose of [6R]-MTHF was 100 mg/m² once weekly in combination with pemetrexed 500 mg/m². The low toxicity profile of [6R]-MTHF supports its further evaluation as a component of systemic chemotherapy in the management of colon and rectal cancer.

Should we be more cautious about replacement of vitamin B12 in patients with cancer receiving cytotoxic chemotherapy?

Vitamin B12 (Cbl) deficiency may cause hematologic and neurologic dysfunction. Replacement therapy is effective in correcting hematologic abnormalities and improving neurologic symptoms. Cbl is known to have antioxidant activity. This antioxidant activity may antagonize the effects of chemotherapeutics (i.e. genotoxic effects of paclitaxel) on tumor DNA. We claim that Cbl replacement should be done more cautiously in patients receiving cytotoxic chemotherapy.

Changes in vitamin and mineral supplement use after breast cancer diagnosis in the Pathways Study: a prospective cohort study

BACKGROUND

Vitamin and mineral supplement use after a breast cancer diagnosis is common and controversial. Dosages used and the timing of initiation and/or discontinuation of supplements have not been clearly described.

METHODS

We prospectively examined changes in use of 17 vitamin/mineral supplements in the first six months following breast cancer diagnosis among 2,596 members (28% non-white) of Kaiser Permanente Northern California. We used multivariable logistic regression to examine demographic, clinical, and lifestyle predictors of initiation and discontinuation.

RESULTS

Most women used vitamin/mineral supplements before (84%) and after (82%) diagnosis, with average doses far in excess of Institute of Medicine reference intakes. Over half (60.2%) reported initiating a vitamin/mineral following diagnosis, 46.3% discontinuing a vitamin/mineral, 65.6% using a vitamin/mineral continuously, and only 7.2% not using any vitamin/mineral supplement before or after diagnosis. The most commonly initiated supplements were calcium (38.2%), vitamin D (32.01%), vitamin B6 (12.3%) and magnesium (11.31%); the most commonly discontinued supplements were multivitamins (17.14%), vitamin C (15.97%) and vitamin E (45.62%). Higher education, higher intake of fruits/vegetables, and receipt of chemotherapy were associated with initiation (p-values <0.05). Younger age and breast-conserving surgery were associated with discontinuation (p-values <0.05).

CONCLUSIONS

In this large cohort of ethnically diverse breast cancer patients, high numbers of women used vitamin/mineral supplements in the 6 months following breast cancer diagnosis, often at high doses and in combination with other supplements. The immediate period after diagnosis is a critical time for clinicians to counsel women on supplement use.