Pyridine-Containing Macrocycles Display MMP-2/9 Inhibitory Activity and Distinct Effects on Migration and Invasion of 2D and 3D Breast Cancer Models.

The role of metalloproteinases (MMPs) on the migration and invasion of cancer cells has been correlated with tumor aggressiveness, namely with the up-regulation of MMP-2 and 9. Herein, two pyridine-containing macrocyclic compounds, [15]pyN5 and [16]pyN5, were synthesized, chemically characterized and evaluated as potential MMP inhibitors for breast cancer therapy using 3D and 2D cellular models. [15]pyN5 and [16]pyN5 (5-20 µM) showed a marked inhibition of MMPs activity (100% at concentrations ≥ 7.5 µM) when compared to ARP-100, a known MMP inhibitor. The inhibitory activity of [15]pyN5 and [16]pyN5 was further supported through in silico docking studies using Goldscore and ChemPLP scoring functions. Moreover, although no significant differences were observed in the invasion studies in the presence of all MMPs inhibitors, cell migration was significantly inhibited by both pyridine-containing macrocycles at concentrations above 5 µM in 2D cells (p < 0.05). In spheroids, the same effect was observed, but only with [16]pyN5 at 20 µM and ARP-100 at 40 µM. Overall, [15]pyN5 and [16]pyN5 led to impaired breast cancer cell migration and revealed to be potential inhibitors of MMPs 2 and 9.

Influence of culture conditions towards optimal carotenoid production by Gordonia alkanivorans strain 1B.

With the increasing awareness on the toxicity of several synthetic dyes, demand for pigments from natural sources, such as microbial carotenoids, has gained interest as a promising safe alternative colour additive. In this study, a surface response methodology based on the Doehlert distribution for two factors [% of glucose in a mixture of glucose + fructose (10 g/L total sugars), and sulfate concentration] was used towards the optimal carotenoids production by Gordonia alkanivorans strain 1B in the presence of light (400 lx). Time influence on pigment production by this bacterium was also evaluated, as well as the cell viability profile during longer incubation periods at optimal conditions. Indeed, the highest carotenoid production (2596-3100 µg/gDCW) was obtained when strain 1B was cultivated in the optimal conditions: glucose 10 g/L and sulfate ≥ 22 mg/L, in the presence of light for 19 days at 30 °C, 150 rpm. Flow cytometry showed that the highest production was somehow related with the cellular stress. These results highlight the great potential of strain 1B as a new hyperpigment producer to be exploited towards several applications.

Design of polymeric nanoparticles and its applications as drug delivery systems for acne treatment.

OBJECTIVE: The aim of this study was to evaluate a formulation made of poly(lactide-co-glycolide) (PLGA) nanoparticles containing azelaic acid for potential acne treatment. METHODS: Azelaic acid-loaded PLGA nanoparticles were prepared by spontaneous emulsification processes using poloxamer 188 as stabilizer. Several manufacturing parameters such as stirring rate, concentration of stabilizer and different recovery methods were investigated. Nanoparticles were evaluated in terms of size, zeta potential, encapsulation efficiency, release kinetics and permeation kinetics in vitro. Furthermore, in vitro toxicological studies were performed in Saccharomyces cerevisiae model. RESULTS: The results showed that by adjusting some formulation conditions it was possible to obtain nanoparticles with high loading and a controlled drug release. Freeze-dried recovery altered the nanoparticles structure by enhancing porous structures and mannitol was required to control the mean particle size. The centrifugation recovery was found to be the best approach to nanoparticles recovery. Similar toxicity profiles were observed for both drug-free and azelaic acid-loaded nanoparticles, with concentration-dependent decreases in cell viability. CONCLUSION: These results indicate a potential formulation for controlled release delivery of azelaic acid to the follicular unit.

[15]aneN4S: synthesis, thermodynamic studies and potential applications in chelation therapy.

The purpose of this work was to synthesize and characterize the thiatetraaza macrocycle 1-thia-4,7,10,13-tetraazacyclopentadecane ([15]aneN4S). Its acid-base behaviour was studied by potentiometry at 25 °C and ionic strength 0.10 M in KNO3. The protonation sequence of this ligand was investigated by 1H-NMR titration that also allowed the determination of protonation constants in D2O. Binding studies of [15]aneN4S with Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+ and Pb2+ metal ions were further performed under the same experimental conditions. The results demonstrated that this compound has a higher selectivity and thermodynamic stability for Hg2+ and Cu2+, followed by Ni2+. The UV-visible-near IR spectroscopies and magnetic moment data for the Co(II) and Ni(II) complexes indicated a tetragonal distorted coordination geometry for both metal centres. The value of magnetic moment and the X-band EPR spectra of the Cu(II) complex are consistent with a distorted square pyramidal geometry.

The ATCC genome portal: 3,938 authenticated microbial reference genomes.

The ATCC Genome Portal (AGP, https://genomes.atcc.org/) is a database of authenticated genomes for bacteria, fungi, protists, and viruses held in ATCC's biorepository. It now includes 3,938 assemblies (253% increase) produced under ISO 9000 by ATCC. Here, we present new features and content added to the AGP for the research community.

Mechanistic insights into the cytotoxicity and genotoxicity induced by glycidamide in human mammary cells.

Acrylamide (AA) is a well-known industrial chemical classified as a probable human carcinogen. Benign and malignant tumours at different sites, including the mammary gland, have been reported in rodents exposed to AA. This xenobiotic is also formed in many carbohydrate-rich foods prepared at high temperatures. For this reason, AA is an issue of concern in terms of human cancer risk. The epoxide glycidamide (GA) is thought to be the ultimate genotoxic AA metabolite. Despite extensive experimental and epidemiological data focused on AA-induced breast cancer, there is still lack of information on the deleterious effects induced by GA in mammary cells. The work reported here addresses the characterisation and modulation of cytotoxicity, generation of reactive oxygen species, formation of micronuclei (MN) and quantification of specific GA-DNA adducts in human MCF10A epithelial cells exposed to GA. The results show that GA significantly induces MN, impairs cell proliferation kinetics and decreases cell viability at high concentrations by mechanisms not involving oxidative stress. KU55933, an inhibitor of ataxia telangiectasia mutated kinase, enhanced the cytotoxicity of GA (P < 0.05), supporting a role of this enzyme in regulating the repair of GA-induced DNA lesions. Moreover, even at low GA levels, N7-GA-Gua adducts were generated in a linear dose-response manner in MCF10A cells. These results confirm that human mammary cells are susceptible to GA toxicity and reinforce the need for additional studies to clarify the potential correlation between dietary AA exposure and breast cancer risk in human populations.

Synthesis and biological activity of 6-selenocaffeine: potential modulator of chemotherapeutic drugs in breast cancer cells.

We report the development of a new microwave-based synthetic methodology mediated by Woollins' reagent that allowed an efficient conversion of caffeine into 6-selenocaffeine. A preliminary evaluation on the modulation of antioxidant activity upon selenation of caffeine, using the DPPH assay, indicated a mild antioxidant activity for 6-selenocaffeine, contrasting with caffeine, that exhibited no antioxidant activity under the same experimental conditions. Interestingly, whereas 6-selenocaffeine has revealed to have a low cytotoxic potential in both MCF10A and MCF-7 breast cells (24 h, up to 100 µM, MTT assay), a differential effect was observed when used in combination with the anticancer agents doxorubicin and oxaliplatin in MCF-7 breast cancer cells. The co-treatment of doxorubicin (1 µM) and 6-selenocaffeine (100 µM) resulted in a slight decrease in cellular viability when compared to doxorubicin (1 µM) alone. Conversely, the seleno-caffeine derivative at the same concentration markedly increased the viability of oxaliplatin (100 µM)-treated cells (p < 0.01). Overall, this work highlights an emerging methodology to synthesize organoselenium compounds and points out the differential roles of 6-selenocaffeine in the modulation of the cytotoxicity of anticancer agents.

Functional Foods for Health: The Antioxidant and Anti-Inflammatory Role of Fruits, Vegetables and Culinary Herbs.

The concept of "functional foods" converges topics such as diet, food, health, and disease [...].

The Dietary Isothiocyanate Erucin Reduces Kidney Cell Motility by Disturbing Tubulin Polymerization.

SCOPE: Epidemiological evidence associates the consumption of cruciferous vegetables with reduced risk of several cancers, including renal cell carcinoma. Erucin can be generated by in vivo reduction of sulforaphane or by enzymatic hydrolysis of glucoerucin. Contrarily to sulforaphane, only limited studies have addressed the anticancer properties of erucin. This study aims at evaluating the impact of erucin on renal cell biology. METHODS AND RESULTS: The effects of erucin were assessed in 786-O and Vero-E6 cells, representative of human renal cancer and non- cancer kidney cells, respectively. Erucin induced a concentration-dependent decrease in cell viability and cell cycle arrest at G2/Mitosis. In Vero-E6 cells erucin modestly reduced intracellular reactive oxygen species levels while in 786-O no effects were detected. After erucin treatment, both cell lines revealed altered morphology, with a concentration-dependent change from an elongated shape towards a smaller round conformation. Moreover, erucin affected cell adhesion and strongly altered the tubulin network structure and specifically microtubule polymerization. These results are in line with the observed decrease in collective and single cell migration and G2/Mitosis arrest. CONCLUSIONS: Overall, erucin may have a beneficial impact in reducing the motility of renal cancer cells. Our results contribute to explore possible dietary approaches for secondary/tertiary renal cancer chemoprevention.

The Redox-Active Manganese(III) Porphyrin, MnTnBuOE-2-PyP5+, Impairs the Migration and Invasion of Non-Small Cell Lung Cancer Cells, Either Alone or Combined with Cisplatin.

Manganese(III) porphyrin MnTnBuOE-2-PyP5+ (MnBuOE, BMX-001) is a third-generation redox-active cationic substituted pyridylporphyrin-based drug with a good safety/toxicity profile that has been studied in several types of cancer. It is currently in four phase I/II clinical trials on patients suffering from glioma, head and neck cancer, anal squamous cell carcinoma and multiple brain metastases. There is yet an insufficient understanding of the impact of MnBuOE on lung cancer. Therefore, this study aims to fill this gap by demonstrating the effects of MnBuOE on non-small cell lung cancer (NSCLC) A549 and H1975 cell lines. The cytotoxicity of MnBuOE alone or combined with cisplatin was evaluated by crystal violet (CV) and/or 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulphophenyl)-2H-Tetrazolium (MTS) reduction assays. Intracellular ROS levels were assessed using two fluorescent probes. Furthermore, the impact of MnBuOE alone or in combination with cisplatin on collective cell migration, individual chemotactic migration and chemoinvasion was assessed using the wound-healing and transwell assays. The expression of genes related to migration and invasion was assessed through RT-qPCR. While MnBuOE alone decreased H1975 cell viability at high concentrations, when combined with cisplatin it markedly reduced the viability of the more invasive H1975 cell line but not of A549 cell line. However, MnBuOE alone significantly decreased the migration of both cell lines. The anti-migratory effect was more pronounced when MnBuOE was combined with cisplatin. Finally, MnBuOE alone or combined with cisplatin significantly reduced cell invasion. MnBuOE alone or combined with cisplatin downregulated MMP2, MMP9, VIM, EGFR and VEGFA and upregulated CDH1 in both cell lines. Overall, our data demonstrate the anti-metastatic potential of MnBuOE for the treatment of NSCLC.

Anthracyclines versus No Anthracyclines in the Neoadjuvant Strategy for HER2+ Breast Cancer: Real-World Evidence.

BACKGROUND AND OBJECTIVES: Deescalation strategies omitting anthracyclines (AC) have been explored in early human epidermal growth factor receptor 2-positive breast cancer (HER2+ EBC), showing similar efficacy regarding pathological complete response (pCR) and long-term outcomes as AC-containing regimens. The standard treatment for this tumor subtype is based on chemotherapy and dual HER2 blockade with trastuzumab and pertuzumab, with AC-containing regimens remaining a frequent option for these patients, even in non-high-risk cases. The primary aim of this study was to assess and compare the effectiveness of neoadjuvant regimens with and without AC used in the treatment of HER2+ EBC in the clinical practice according to the pCR achieved with each. METHODS: This retrospective multicentric study included patients with HER2+ EBC from Portuguese, Spanish, and Chilean hospitals (January 2018-December 2021). Patients receiving neoadjuvant therapy (NAT) with dual HER2 blockade (trastuzumab and pertuzumab), followed by surgery, were included. Statistical analysis used chi-squared/Fisher's exact test for associations, multivariate logistic regression for pCR, and Kaplan-Meier method for event-free survival (EFS). IBM SPSS Statistics 29.0 analyzed the data. RESULTS: The study included 371 patients from eight hospitals. Among them, 237 received sequential AC and taxane-based chemotherapy with 4 cycles of trastuzumab and pertuzumab, while 134 received 6 cycles of TCHP (docetaxel, carboplatinum, trastuzumab, and pertuzumab). The average age of the patients was 52.8 years and 52.7 years, respectively. Omitting AC from the neoadjuvant approach did not preclude achieving pCR [p = 0.246, 95% confidence interval (CI) 0.235-0.257] and was safe regardless of patient characteristics. Relapse rates were 6.8% (16 patients) in the AC group and 4.5% (6 patients) in the TCHP group. Over a median follow-up of 2.9 years, the estimated 3-year EFS was 92.5% in the AC group and 95.4% in the TCHP group (hazard ratio 0.602, 95% CI 0.234-1.547, p = 0.292, favoring TCHP). CONCLUSION: This study reports real-world evidence showing similar pCR and EFS outcomes with treatment regimens with and without AC and raises awareness of possible overtreatment and long-term toxicity in some patients with HER2+ EBC with the use of AC.

Lysyl Oxidases Expression and Breast Cancer Progression: A Bioinformatic Analysis.

LOX (Lysyl oxidase) and LOX like 1-4 (LOXL1-4) are amine oxidases that catalyse the cross-linking of elastin and collagen in the extracellular matrix (ECM). This activity can facilitate cell migration and the formation of metastases. Consequently, inhibition of these enzymes and, in particular of LOXL2, has been suggested as a therapeutic strategy to prevent breast cancer metastasis. Although medicinal chemistry studies have struggled to specifically inhibit LOXL2, the importance of selectivity in this context is not clear. To explore the role of each LOX in breast cancer and consequently their potential as biomarkers or therapeutic targets, a bioinformatic-based approach was followed. The expression profile of LOXs, the putative associations among mRNA expression from each LOX and clinical observations, the correlation between expression of LOX enzymes and other genes, and the association between expression of LOXs and the tumour infiltrates were assessed for breast cancer. Overall, the patient outcome and the characteristics of breast tumours with LOX, LOXL1 and LOXL2 upregulation is distinct from those with high expression of LOXL3 and LOXL4. Additionally, the expression correlation between LOXs and other genes involved in cellular processes relevant for cancer biology, also reveals a similar trend for LOX, LOXL1 and LOX2. This work further supports the relevance of LOXL2 as a breast cancer progression biomarker and therapeutic target. We speculate that while the impact of LOXL3 inhibition may vary with breast cancer subtype, the therapeutical inhibition of LOX, LOXL1 and LOXL2 but not of LOXL4 may be the most beneficial.

Polyphenols and Their Metabolites in Renal Diseases: An Overview.

Kidney diseases constitute a worldwide public health problem, contributing to morbidity and mortality. The present study aimed to provide an overview of the published data regarding the potential beneficial effects of polyphenols on major kidney diseases, namely acute kidney injury, chronic kidney disease, diabetic nephropathy, renal cancer, and drug-induced nephrotoxicity. This study consists of a bibliographical review including in vitro and in vivo studies dealing with the effects of individual compounds. An analysis of the polyphenol metabolome in human urine was also conducted to estimate those compounds that are most likely to be responsible for the kidney protective effects of polyphenols. The biological effects of polyphenols can be highly attributed to the modulation of specific signaling cascades including those involved in oxidative stress responses, anti-inflammation processes, and apoptosis. There is increasing evidence that polyphenols afford great potential in renal disease protection. However, this evidence (especially when in vitro studies are involved) should be considered with caution before its clinical translation, particularly due to the unfavorable pharmacokinetics and extensive metabolization that polyphenols undergo in the human body. Future research should consider polyphenols and their metabolites that indeed reach kidney tissues.

Tumor-infiltrating lymphocytes in early breast cancer: an exploratory analysis focused on HER2+ subtype in Portuguese patients.

Tumor-infiltrating lymphocytes (TILs) have shown prognostic value in breast cancer. This study evaluated the TILs scores in 186 Portuguese patients diagnosed with early breast cancer, with special focus on HER2 subtype. Stromal TILs were scored on the core needle biopsies, as well as in the resected specimen in HER2+ patients submitted to neoadjuvant treatment with trastuzumab and pertuzumab. TILs were higher in tumors with negative hormone receptor status and HER2 amplifications, and in triple-negative breast cancer. In HER2+ patients treated with dual anti-HER neoadjuvant therapy, the TILs score on the surgical specimen was generally lower than in the biopsy.

MnTnHex-2-PyP5+ Displays Anticancer Properties and Enhances Cisplatin Effects in Non-Small Cell Lung Cancer Cells.

The manganese(III) porphyrin MnTnHex-2-PyP5+ (MnTnHex) is a potent superoxide dismutase mimic and modulator of redox-based transcriptional activity that has been studied in the context of different human disease models, including cancer. Nevertheless, for lung cancer, hardly any information is available. Thus, the present work aims to fill this gap and reports the effects of MnTnHex in non-small cell lung cancer (NSCLC) cells, more specifically, A549 and H1975 cells, in vitro. Both cell lines were initially characterized in terms of innate levels of catalase, glutathione peroxidase 1, and peroxiredoxins 1 and 2. To assess the effect of MnTnHex in NSCLC, alone or in combination with cisplatin, endpoints related to the cell viability, cell cycle distribution, cell motility, and characterization of the volatile carbonyl compounds (VCCs) generated in the extracellular medium (i.e., exometabolome) were addressed. The results show that MnTnHex as a single drug markedly reduced the viability of both NSCLC cell lines, with some IC50 values reaching sub-micromolar levels. This redox-active drug also altered the cell cycle distribution, induced cell death, and increased the cytotoxicity pattern of cisplatin. MnTnHex also reduced collective cell migration. Finally, the metabolomics study revealed an increase in the levels of a few VCCs associated with oxidative stress in MnTnHex-treated cells. Altogether these results suggest the therapeutic potential of MnTnHex to be further explored, either alone or in combination therapy with cisplatin, in NSCLC.

LOXL2 Inhibitors and Breast Cancer Progression.

LOX (lysyl oxidase) and lysyl oxidase like-1-4 (LOXL 1-4) are amine oxidases, which catalyze cross-linking reactions of elastin and collagen in the connective tissue. These amine oxidases also allow the cross-link of collagen and elastin in the extracellular matrix of tumors, facilitating the process of cell migration and the formation of metastases. LOXL2 is of particular interest in cancer biology as it is highly expressed in some tumors. This protein also promotes oncogenic transformation and affects the proliferation of breast cancer cells. LOX and LOXL2 inhibition have thus been suggested as a promising strategy to prevent metastasis and invasion of breast cancer. BAPN (ß-aminopropionitrile) was the first compound described as a LOX inhibitor and was obtained from a natural source. However, novel synthetic compounds that act as LOX/LOXL2 selective inhibitors or as dual LOX/LOX-L inhibitors have been recently developed. In this review, we describe LOX enzymes and their role in promoting cancer development and metastases, with a special focus on LOXL2 and breast cancer progression. Moreover, the recent advances in the development of LOXL2 inhibitors are also addressed. Overall, this work contextualizes and explores the importance of LOXL2 inhibition as a promising novel complementary and effective therapeutic approach for breast cancer treatment.

A narrative review of the migration and invasion features of non-small cell lung cancer cells upon xenobiotic exposure: insights from in vitro studies.

Lung cancer (LC) is the leading cause of cancer deaths worldwide, being non-small lung cancer (NSCLC) sub-types the most prevalent. Since most LC cases are only detected during the last stage of the disease the high mortality rate is strongly associated with metastases. For this reason, the migratory and invasive capacity of these cancer cells as well as the mechanisms involved have long been studied to uncover novel strategies to prevent metastases and improve the patients' prognosis. This narrative review provides an overview of the main in vitro migration and invasion assays employed in NSCLC research. While several methods have been developed, experiments using conventional cell culture models prevailed, specifically the wound-healing and the transwell migration and invasion assays. Moreover, it is provided herewith a summary of the available information concerning chemical contaminants that may promote the migratory/invasive properties of NSCLC cells in vitro, shedding some light on possible LC risk factors. Most of the reported agents with pro-migration/invasion effects derive from cigarette smoking [e.g., Benzo(a)pyrene and cadmium] and air pollution. This review further presents several studies in which different dietary/plant-derived compounds demonstrated to impair migration/invasion processes in NSCLC cells in vitro. These chemicals that have been proposed as anti-migratory consisted mainly of natural bioactive substances, including polyphenols non-flavonoids, flavonoids, bibenzyls, terpenes, alkaloids, and steroids. Some of these compounds may eventually represent novel therapeutic strategies to be considered in the future to prevent metastasis formation in LC, which highlights the need for additional in vitro methodologies that more closely resemble the in vivo tumor microenvironment and cancer cell interactions. These studies along with adequate in vivo models should be further explored as proof of concept for the most promising compounds.

Increased antibacterial properties of indoline-derived phenolic Mannich bases.

The search for antibacterial agents for the combat of nosocomial infections is a timely problem, as antibiotic-resistant bacteria continue to thrive. The effect of indoline substituents on the antibacterial properties of aminoalkylphenols was studied, leading to the development of a library of compounds with minimum inhibitory concentrations (MICs) as low as 1.18 µM. Two novel aminoalkylphenols were identified as particularly promising, after MIC and minimum bactericidal concentrations (MBC) determination against a panel of reference strain Gram-positive bacteria, and further confirmed against 40 clinical isolates (Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Enterococcus faecium, and Listeria monocytogenes). The same two aminoalkylphenols displayed low toxicity against two in vivo models (Artemia salina brine shrimp and Saccharomyces cerevisiae). The in vitro cytotoxicity evaluation (on human keratinocytes and human embryonic lung fibroblast cell lines) of the same compounds was also carried out. They demonstrated a particularly toxic effect on the fibroblast cell lines, with IC50 in the 1.7-5.1 µM range, thus narrowing their clinical use. The desired increase in the antibacterial properties of the aminoalkylphenols, particularly indoline-derived phenolic Mannich bases, was reached by introducing an additional nitro group in the indolinyl substituent or by the replacement of a methyl by a bioisosteric trifluoromethyl substituent in the benzyl group introduced through use of boronic acids in the Petasis borono-Mannich reaction. Notably, the introduction of an additional nitro moiety did not confer added toxicity to the aminoalkylphenols.

Oxidative injury in V79 Chinese hamster cells: protective role of the superoxide dismutase mimetic MnTM-4-PyP.

Oxidative cell injury could be induced by different reactive oxygen species (ROS) operating in multiple pathways. The present work is focused on three different models of oxidative stress: the xanthine/xanthine oxidase system (XXO), an extracellular superoxide anion generator; tert-butylhydroperoxide (TBHP), an analogue of lipid hydroperoxides; and doxorubicin (Dox), an anticancer drug. Superoxide and peroxyl radicals, among other ROS, could be effectively scavenged by MnTM-4-PyP, a polyfunctional catalytic antioxidant. In this report, we have addressed the role of MnTM-4-PyP on the protection against the cytotoxicity induced by the three aforementioned oxidants. The effect of MnTM-4-PyP (0.1-100 microM) was evaluated in V79 fibroblasts using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide reduction and the crystal violet assays, as well as the mitotic index. Also, the generation of intracellular ROS was studied by the fluorescent probe dihydroethidium. MnTM-4-PyP has shown significant protective effects against the cytotoxicity of XXO and TBHP, increasing the cell viability in approximately 40% and reducing the intracellular level of ROS. However, no considerable protection occurred against Dox. The three oxidants caused a mitotic index reduction that was not altered by MnTM-4-PyP. In summary, MnTM-4-PyP appears to be a promising agent for the protection against oxidative injury. However, it has shown differential responses, reinforcing the need to study different experimental models for the adequate evaluation of its potentialities as a catalytic antioxidant.

Exploring Volatile Organic Compound Exposure and Its Association with Wheezing in Children under 36 Months: A Cross-Sectional Study in South Lisbon, Portugal.

Air quality and other environmental factors are gaining importance in public health policies. Some volatile organic compounds (VOCs) have been associated with asthma and symptoms of respiratory disease such as wheezing. The aim of this study was to measure the concentration of Total VOCs and assess their possible association with the occurrence of wheezing episodes in children under 36 months of age, in a region south of Lisbon, Portugal. A cross-sectional study was performed from October 2015 to March 2016. The sample of children under 36 months of age was selected by convenience, by inviting parents to take part in the study. A survey was applied to collect information on bedroom features, as well as to verify the occurrence of wheezing episodes. The indoor air quality parameters of bedrooms were measured using three 3M Quest® EVM-7 environmental monitors. In total, 34.4% of infants had had wheezing episodes since birth, with 86.7% of these presenting at least one episode in the previous 12 months. Total VOC levels were above the reference values in 48% of the analyzed bedrooms. No significant association of VOC exposure in a domestic setting with episodes of wheezing was found. However, children living in households with smokers were 4 times more likely to develop wheezing episodes. Thus, this study provides relevant information that warrants further studies to assess infant exposure to indoor air pollution and parental smoking in a residential context.