Impact of low- or moderate-risk gonadotoxic chemotherapy prior to testicular tissue freezing on spermatogonia quantity in human (pre)pubertal testicular tissue.

STUDY QUESTION: What is the impact of low- or moderate-risk gonadotoxic chemotherapy received prior to testicular tissue freezing (TTF), and of the cancer itself, on spermatogonia quantity in testicular tissue from (pre)pubertal boys? SUMMARY ANSWER: Vincristine, when associated with alkylating agents, has an additional adverse effect on spermatogonia quantity, while carboplatin has no individual contribution to spermatogonia quantity, in testicular tissue of (pre)pubertal boys, when compared to patients who have received non-alkylating chemotherapy. WHAT IS KNOWN ALREADY: The improved survival rates after cancer treatment necessitate the inclusion of fertility preservation procedures as part of the comprehensive care for patients, taking into consideration their age. Sperm cryopreservation is an established procedure in post-pubertal males while the TTF proposed for (pre)pubertal boys remains experimental. Several studies exploring testicular tissue of (pre)pubertal boys after TTF have examined the tubular fertility index (TFI, percentage of seminiferous tubule cross-sections containing spermatogonia) and the number of spermatogonia per seminiferous tubule cross-section (S/T). All studies have demonstrated that TFI and S/T always decrease after the introduction of chemotherapeutic agents, especially those which carry high gonadotoxic risks such as alkylating agents. STUDY DESIGN, SIZE, DURATION: Testicular tissue samples from 79 (pre)pubertal boys diagnosed with cancer (from 6 months to 16 years of age) were cryopreserved between May 2009 and June 2014. Their medical diagnoses and previous chemotherapy exposures were recorded. We examined histological sections of (pre)pubertal testicular tissue to elucidate whether the chemotherapy or the primary diagnosis affects mainly TFI and S/T. PARTICIPANTS/MATERIALS, SETTING, METHODS: (Pre)pubertal boys with cancer diagnosis who had been offered TTF prior to conditioning treatment for hematopoietic stem cell transplantation were included in the study. All the patients had previously received chemotherapy with low- or moderate-risk for future fertility. We have selected patients for whom the information on the chemotherapy received was complete. The quantity of spermatogonia and quality of testicular tissue were assessed by both morphological and immunohistochemical analyses. MAIN RESULTS AND THE ROLE OF CHANCE: A significant reduction in the number of spermatogonia was observed in boys treated with alkylating agents. The mean S/T values in boys exposed to alkylating agents were significantly lower compared to boys exposed to non-alkylating agents (P = 0.018). In contrast, no difference was observed for patients treated with carboplatin as the sole administered alkylating agent compared to the group of patients exposed to non-alkylating agents. We observed an increase of S/T with age in the group of patients who did not receive any alkylating agent and a decrease of S/T with age when patients received alkylating agents included in the cyclophosphamide equivalent dose (CED) formula (r = 0.6166, P = 0.0434; r = -0.3759, P = 0.0036, respectively). The TFI and S/T decreased further in the group of patients who received vincristine in combination with alkylating agents (decrease of 22.4%, P = 0.0049 and P < 0.0001, respectively), but in this group the CED was also increased significantly (P < 0.0001). Multivariate analysis, after CED adjustment, showed the persistence of a decrease in TFI correlated with vincristine administration (P = 0.02). LIMITATIONS, REASONS FOR CAUTION: This is a descriptive study of testicular tissues obtained from (pre)pubertal boys who were at risk of infertility. The study population is quite heterogeneous, with a small number of patients in each sub-group. Our results are based on comparisons between patients receiving alkylating agents compared to patients receiving non-alkylating agents rather than chemotherapy-naive patients. The French national guidelines for fertility preservation in cancer patients recommend TTF before highly gonadotoxic treatment. Therefore, all the patients had received low- or moderate-risk gonadotoxic chemotherapy before TTF. Access to testicular tissue samples from chemotherapy-naive patients with comparable histological types of cancer was not possible. The functionality of spermatogonia and somatic cells could not be tested by transplantation or in vitro maturation due to limited sample sizes. WIDER IMPLICATIONS OF THE FINDINGS: This study summarizes the spermatogonial quantity of (pre)pubertal boys prior to TTF. We confirmed a negative correlation between the cumulative exposure to alkylating agents and spermatogonial quantity. In addition, the synergistic use of vincristine in combination with alkylating agents showed a cumulative deleterious effect on the TFI. For patients for whom fertility preservation is indicated, TTF should be proposed for chemotherapy with a predicted CED above 4000 mg/m2. However, the data obtained from vincristine and carboplatin use should be confirmed in a subsequent study including more patients. STUDY FUNDING/COMPETING INTEREST(S): This study had financial support from a French national research grant PHRC No. 2008/071/HP obtained by the French Institute of Cancer and the French Healthcare Organization. The sponsors played no role in the study. The authors declare no conflicts of interest. TRIAL REGISTRATION NUMBER: N/A.

Fertility restoration in mice with chemotherapy induced ovarian failure using differentiated iPSCs.

BACKGROUND: Treatment options for premature ovarian insufficiency (POI) are limited to hormone replacement and donor oocytes. A novel induced pluripotent stem cell (iPSC) transplant paradigm in a mouse model has potential translational applications for management of POI. METHODS: Mouse ovarian granulosa cell derived-iPSCS were labelled with green fluorescent protein (GFP) reporter and differentiated in vitro into oocytes. Differentiated cells were assayed for estradiol and progesterone secretion by enzyme-linked immunosorbent assays. After Fluorescence-Activated Cell Sorting (FACS) for the cell surface marker anti-Mullerian hormone receptor (AMHR2), enriched populations of differentiated cells were surgically transplanted into ovaries of mice that had POI secondary to gonadotoxic pre-treatment with alkylating agents. A total of 100 mice were used in these studies in five separate experiments with 56 animals receiving orthotopic ovarian injections of either FACS sorted or unsorted differentiated iPSCSs and the remaining animals receiving sham injections of PBS diluent. Following transplantation surgery, mice were stimulated with gonadotropins inducing oocyte development and underwent oocyte retrieval. Nine transplanted mice were cross bred with wild-type mice to assess fertility. Lineage tracing of resultant oocytes, F1 (30 pups), and F2 (42 pups) litters was interrogated by GFP expression and validation by short tandem repeat (STR) lineage tracing. FINDINGS: [1] iPSCs differentiate into functional oocytes and steroidogenic ovarian cells which [2] express an ovarian (GJA1) and germ cell (ZP1) markers. [3] Endocrine function and fertility were restored in mice pretreated with gonadotoxic alkylating agents via orthotopic transplantation of differentiated iPSCS, thus generating viable, fertile mouse pups. INTERPRETATION: iPSC-derived ovarian tissue can reverse endocrine and reproductive sequelae of POI. FUNDING: Center for Infertility and Reproductive Surgery Research Award, Siezen Foundation award (RMA). Reproductive Scientist Development Program, Marriott Foundation, Saltonstall Foundation, Brigham Ovarian Cancer Research Fund (K.E).

PQQ Dietary Supplementation Prevents Alkylating Agent-Induced Ovarian Dysfunction in Mice.

Alkylating agents (AAs) that are commonly used for cancer therapy cause great damage to the ovary. Pyrroloquinoline-quinine (PQQ), which was initially identified as a redox cofactor for bacterial dehydrogenases, has been demonstrated to benefit the fertility of females. The aim of this study was to investigate whether PQQ dietary supplementation plays a protective role against alkylating agent-induced ovarian dysfunction. A single dose of busulphan (20 mg/kg) and cyclophosphamide (CTX, 120 mg/kg) were used to establish a mouse model of ovarian dysfunction. Feed containing PQQNa2 (5 mg/kg) was provided starting 1 week before the establishment of the mouse model until the date of sacrifice. One month later, estrous cycle period of mice were examined and recorded for consecutive 30 days. Three months later, some mice were mated with fertile male mice for fertility test. The remaining mice were sacrificed to collect serum samples and ovaries. One day before sacrifice, some mice received a single injection of BrdU to label proliferating cells. Serum samples were used for test hormonal levels. Ovaries were weighted and used to detect follicle counts, cell proliferation, cell apoptosis and cell senescence. In addition, the levels of inflammation, oxidative damage and Pgc1α expression were detected in ovaries. Results showed that PQQ treatment increased the ovarian weight and size, partially normalized the disrupted estrous cycle period and prevented the loss of follicles of mice treated with AAs. More importantly, we found that PQQ treatment significantly increased the pregnancy rate and litter size per delivery of mice treated with AAs. The protective effects of PQQ appeared to be directly mediated by promoting cell proliferation of granulosa, and inhibiting cell apoptosis of granulosa and cell senescence of ovarian stromal cells. The underlying mechanisms may attribute to the anti-oxidative stress, anti-inflammation and pro-mitochondria biogenesis effects of PQQ.Our study highlights the therapeutic potential of PQQ against ovarian dysfunction caused by alkylating agents.

Microbiome, fibrosis and tumor networks in a non-alcoholic steatohepatitis model of a choline-deficient high-fat diet using diethylnitrosamine.

BACKGROUND & AIMS: Hepatocellular carcinoma in nonalcoholic steatohepatitis is caused by the complex factors of inflammation, fibrosis and microbiomes. We used network analysis to examine the interrelationships of these factors. METHODS: C57Bl/6 mice were categorized into groups: choline-sufficient high-fat (CSHF, n = 8), choline-deficient high-fat (CDHF, n = 9), and CDHF+ diethylnitrosamine (DEN, n = 8). All mice were fed CSHF or CDHF for 20 weeks starting at week 8, and mice in the CDHF + DEN group received one injection of DEN at 3 weeks of age. Bacterial gene was isolated from feces and analyzed using Miseq. RESULTS: The CSHF group had less fibrosis than the other groups. Tumors were found in 22.2% and 87.5% of the CDHF group and CDHF + DEN groups, respectively. Gene expression in the liver of Cdkn1a (p21: tumor-suppressor) and c-jun was highest in the CDHF group. Bacteroides, Roseburia, Odoribacter, and Clostridium correlated with fibrosis. Streptococcus and Dorea correlated with inflammation and tumors. Akkermansia and Bilophila were inversely correlated with fibrosis and Bifidobacterium was inversely correlated with tumors. CONCLUSIONS: DEN suppressed the overexpression of p21 caused by CDHF. Some bacteria formed a relationship networking associated with their progression and inhibition for tumors and fibrosis.

Quantification of 3-Hydroxypropyl Mercapturic Acid in the Urine of Patients with Breast Cancer to Monitor Cyclophosphamide Toxicity.

BACKGROUND: The alkylating agent cyclophosphamide is used in chemotherapy regimens for various type of cancer. However, cyclophosphamide may lead to toxic side effects on the bladder, namely hemorrhagic cystitis, which can cause hematuria, and, potentially, bladder cancer. These effects are caused by acrolein, a byproduct of cyclophosphamide metabolism. In this study, a method to quantify 3-hydroxypropyl mercapturic acid (3-HPMA) in urine was developed. 3-HPMA is a stable metabolite of acrolein that serves as biomarker of acrolein. METHODS: Urine samples were collected 4 hours after cyclophosphamide administration and analyzed to determine the risk of hematuria. 3-HPMA was analyzed by reverse-phase LC-MS/MS using a triple quadrupole electrospray ionization mass spectrometer in the positive-ion mode. The mobile phase was a 90:10 (vol/vol) mixture of 0.1% formic acid in water and 0.1% formic acid in acetonitrile. Multiple reaction monitoring mode was used, with m/z 222.10 → 90.97 for 3-HPMA and 164.10 → 122.02 for the internal standard N-acetyl cysteine (NAC). Samples were prepared by acidification and dilution. RESULTS: The analytical method produced a linear response within the concentration range of 40-10,000 ng/mL. The method was validated in accordance with 2018 FDA guidelines and applied to quantify 3-HPMA in the urine of 40 patients with breast cancer. The measured concentrations ranged from 820.3 to 5596.1 ng/mg creatinine. Seven patients identified with hematuria had low 3-HPMA concentrations of 4445.824 ± 411.17 ng/mg creatinine, and 33 patients without hematuria had low 3-HPMA concentrations of 2419.4 ± 1171.8 ng/mg creatinine. CONCLUSIONS: The method was applicable for the quantification of 3-HPMA in human urine. Large variations in 3-HPMA concentrations were found in 40 patients with breast cancer treated with cyclophosphamide, with a significant difference (P < 0.05) observed between patients with hematuria and those without hematuria.

In vitro metabolism of naphthalene and its alkylated congeners by human and rat liver microsomes via alkyl side chain or aromatic oxidation.

Mineral oils are widely applied in food production and processing and may contain polycyclic aromatic hydrocarbons (PAHs). The PAHs that may be present in mineral oils are typically alkylated, and have been barely studied. Metabolic oxidation of the aromatic ring is a key step to form DNA-reactive PAH metabolites, but may be less prominent for alkylated PAHs since alkyl substituents would facilitate side chain oxidation as an alternative. The current study investigates this hypothesis of preferential side chain oxidation at the cost of aromatic oxidation using naphthalene and a series of its alkyl substituted analogues as model compounds. The metabolism was assessed by measuring metabolite formation in rat and human liver microsomal incubations using UPLC and GC-MS/MS. The presence of an alkyl side chain markedly reduced aromatic oxidation for all alkyl-substituted naphthalenes that were converted. 1-n-Dodecyl-naphthalene was not metabolized under the experimental conditions applied. With rat liver microsomes for 1-methyl-, 2-methyl-, 1-ethyl-, and 2-ethyl- naphthalene, alkyl side chain oxidation was preferred over aromatic oxidation. With human liver microsomes this was the case for 2-methyl-, and 2-ethyl-naphthalene. It is concluded that addition of an alkyl substituent in naphthalene shifts metabolism in favor of alkyl side chain oxidation at the cost of aromatic ring oxidation. Furthermore, alkyl side chains of 6 or more carbon atoms appeared to seriously hamper and reduce overall metabolism, metabolic conversion being no longer observed with the C12 alkyl side chain. In summary, alkylation of PAHs likely reduces their chances of aromatic oxidation and bioactivation.

A Novel Depurination Methodology to Assess DNA Alkylation of Chloro-Bis-Seco-Cyclopropylbenzoindoles Allowed for Comparison of Minor-Groove Reactivity.

Duocarmycins [including cyclopropyl pyrroloindole (CPI) or cyclopropyl benzoindole (CBI)] are a class of DNA minor-groove alkylators and seco-CPI/CBIs are synthetic pro-forms that can spirocyclize to CPI/CBI. Bis-CPI/CBIs are potential drug candidates because of their enhanced cytotoxicity from DNA crosslinking, but it is difficult to analyze them for structure-activity correlation because of their DNA reactivity. To study their DNA alkylation, neutral thermal hydrolysis has been frequently applied to process depurination. However, unwanted side reactions under this condition have been reported, which could lead to poor correlation of DNA alkylation data with efficacy results, especially for bis-CPI/CBIs. In this study, an acidic depurination method was developed and applied for analysis of DNA alkylation and shown to be an easier and milder method than the traditional neutral thermal hydrolysis. DNA alkylation and stability of three bis-seco-CBIs were characterized in comparison with two mono-seco-CPIs. The results suggested that: 1) The acidic depurination method was capable of capturing a more representative population, sometimes a different population, of DNA adducts as they existed on DNA compared with the heat depurination method. 2) Di-adenine adducts were captured as expected for the CBI dimers, although the major type of adduct was still mono-adenine adducts. 3) The rate of DNA alkylation, DNA adduct profile, and relative amounts of di-adduct versus mono-adduct were significantly affected by the size, and possibly lipophilicity, of the nonalkylating part of the molecules. 4) Spirocyclization and amide hydrolysis represented two major pathways of degradation. Overall, by applying acidic depurination analyses, this study has illustrated DNA adduct characteristics of novel bis-seco-CBIs with dominating mono-alkylation and provides an alternative method for evaluating DNA minor-groove alkylators. These findings provide an effective analytical tool to evaluate DNA alkylators and to study the DNA alkylation that is a disposition mechanism of these compounds.

Community dynamics in a nitrate-reducing microbial consortium cultivated with p-alkylated vs. non-p-alkylated aromatic compounds.

In this study, we established the nitrate-reducing, aromatic compound-degrading enrichment culture pMB18. Its community structure was controlled by the aromatic substrate applied. In the presence of a p-alkylated substrate, microorganisms related to Sulfuritalea, Ignavibacterium and Comamonadaceae were abundant. Non-p-alkylated structural analogues promoted the enrichment of Azoarcus, which was probably favored by the excretion of nitrite. The analysis of the bamA gene, which is a functional marker for anaerobic aromatic compound degradation, as well as a differential abundance analysis suggested the involvement of Sulfuritalea and Comamonadaceae in the degradation of p-alkylated substrates. Members of the genus Azoarcus were assumed to be the key players for the degradation of the non-p-alkylated substrates. A gene cluster encoding a putative 4-methylbenzoyl-CoA reductase, which is supposed to be specific for the dearomatization of p-alkylated benzoyl-CoA intermediates, was detected in culture pMB18 dominated by Sulfuritalea, Ignavibacterium and Comamonadaceae, but not in an Azoarcus-dominated culture. This study allowed insight into a microbial community, whose composition was guided by the aromatic substrate applied.

Design, synthesis, nuclear localization, and biological activity of a fluorescent duocarmycin analog, HxTfA.

HxTfA 4 is a fluorescent analog of a potent cytotoxic and antimalarial agent, TfA 3, which is currently being investigated for the development of an antimalarial vaccine, PlasProtect®. HxTfA contains a p-anisylbenzimidazole or Hx moiety, which is endowed with a blue emission upon excitation at 318 nm; thus enabling it to be used as a surrogate for probing the cellular fate of TfA using confocal microscopy, and addressing the question of nuclear localization. HxTfA exhibits similar selectivity to TfA for A-tract sequences of DNA, alkylating adenine-N3, albeit at 10-fold higher concentrations. It also possesses in vitro cytotoxicity against A549 human lung carcinoma cells and Plasmodium falciparum. Confocal microscopy studies showed for the first time that HxTfA, and by inference TfA, entered A549 cells and localized in the nucleus to exert its biological activity. At biologically relevant concentrations, HxTfA elicits DNA damage response as evidenced by a marked increase in the levels of γH2AX observed by confocal microscopy and immunoblotting studies, and ultimately induces apoptosis.

Simultaneous Mass Spectrometric Analysis of Methylated and Ethylated Peptides in Human Hemoglobin: Correlation with Cigarette Smoking.

Alkylating agents contained in cigarettes smoke might be related to cancer development. Post-translational protein methylation and ethylation may cause alteration of protein functions. Human hemoglobin (Hb) has been a target for molecular dosimetry because of its easy accessibility. The goal of this study is to investigate the relationship between the levels of methylation and ethylation at specific sites of Hb with smoking. Because of the low extent of modification of Hb isolated from blood, the methylation and ethylation sites were identified in Hb incubated with a methylating agent (methyl methanesulfonate, MMS) and ethylating agent (ethyl methanesulfonate, EMS), respectively, by accurate mass measurements. After trypsin digestion, the modification sites were identified by nanoflow LC-nanospray ionization coupled with high-resolution mass spectrometry. The selected reaction monitoring mode was used to quantify the relative extent of methylation and ethylation in human Hb incubated with MMS and EMS, respectively. Methylation occurred at 9 sites, including 1V, 20H, 50H, 72H of α-globin and 1V, 26E, 66K, 77H, 93C of ß-globin. Ethylation was detected at 11 sites, including 1V, 16K, 50H, 72H, 87H of α-globin and 1V, 17K, 66K, 77H, 92H, 93C of ß-globin. The relative extents of methylation and ethylation were measured in blood samples from 13 smokers and 13 nonsmokers. No statistically significant difference was found in the methylated peptides. On the other hand, the extents of ethylation at α-terminal Val, α-His-50, α-His-87, ß-terminal Val, ß-His-77, and ß-Cys-93 in Hb were significantly higher in smokers than in nonsmokers (p < 0.05). Furthermore, the relative extents of ethylation at these sites were statistically significantly correlated with the number of cigarettes smoked per day. Therefore, this assay, which requires as little as one drop of blood, should be helpful in measuring Hb ethylation as a potential biomarker for assessing the exposure to cigarette smoking.