The 100,000 most influential scientists rank: the underrepresentation of Brazilian women in academia.

Despite the progress observed in recent years, women are still underrepresented in science worldwide, especially at top positions. Many factors contribute to women progressively leaving academia at different stages of their career, including motherhood, harassment and conscious and unconscious discrimination. Implicit bias plays a major negative role in recognition, promotions and career advancement of female scientists. Recently, a rank of the most influential scientists in the world was created based on several metrics, including the number of published papers and citations. Here, we analyzed the representation of Brazilian scientists in this rank, focusing on gender. Female Brazilian scientists are greatly underrepresented in the rank (11% in the Top 100,000; 18% in the Top 2%). Possible reasons for this observed scenario are related to the metrics used to rank scientists, which reproduce and amplify the well-known implicit bias in peer-review and citations. Male scientists have more self-citation than female scientists and positions in the rank varied when self-citations were included, suggesting that self-citation by male scientists increases their visibility. Discussions on the repercussions of such ranks are pivotal to avoid deepening the gender gap in science.

Glioblastoma: therapeutic challenges, what lies ahead.

Glioblastoma (GBM) is one of the most aggressive human cancers. Despite current advances in multimodality therapies, such as surgery, radiotherapy and chemotherapy, the outcome for patients with high grade glioma remains fatal. The knowledge of how glioma cells develop and depend on the tumor environment might open opportunities for new therapies. There is now a growing awareness that the main limitations in understanding and successfully treating GBM might be bypassed by the identification of a distinct cell type that has defining properties of somatic stem cells, as well as cancer-initiating capacity - brain tumor stem cells, which could represent a therapeutic target. In addition, experimental studies have demonstrated that the combination of antiangiogenic therapy, based on the disruption of tumor blood vessels, with conventional chemotherapy generates encouraging results. Emerging reports have also shown that microglial cells can be used as therapeutic vectors to transport genes and/or substances to the tumor site, which opens up new perspectives for the development of GBM therapies targeting microglial cells. Finally, recent studies have shown that natural toxins can be conjugated to drugs that bind to overexpressed receptors in cancer cells, generating targeted-toxins to selectively kill cancer cells. These targeted-toxins are highly effective against radiation- and chemotherapy-resistant cancer cells, making them good candidates for clinical trials in GBM patients. In this review, we discuss recent studies that reveal new possibilities of GBM treatment taking into account cancer stem cells, angiogenesis, microglial cells and drug delivery in the development of new targeted-therapies.

Bias against parents in science hits women harder.

Worldwide, parenthood remains a major driver for the reduced participation of women in the job market, where discrimination stems from people's biases against mothers, based on stereotypes and misconceptions surrounding the vision of motherhood in our society. In academia, parenthood may be perceived as negatively affecting scientists' commitment and dedication, especially women's. We conducted a survey amongst Brazilian scientists and found that mothers self-reported a higher prevalence of negative bias in their workplace when compared to fathers. The perception of a negative bias was influenced by gender and career status, but not by race, scientific field or number of children. Regarding intersections, mothers with less than 15 years of hiring reported having suffered a higher rate of negative bias against themselves. We discuss implications of these results and suggest how this negative bias should be addressed in order to promote an equitable environment that does not harm women in science.

Gender, Race and Parenthood Impact Academic Productivity During the COVID-19 Pandemic: From Survey to Action.

The coronavirus disease 2019 (COVID-19) pandemic is altering dynamics in academia, and people juggling remote work and domestic demands - including childcare - have felt impacts on their productivity. Female authors have faced a decrease in paper submission rates since the beginning of the pandemic period. The reasons for this decline in women's productivity need to be further investigated. Here, we analyzed the influence of gender, parenthood and race on academic productivity during the pandemic period based on a survey answered by 3,345 Brazilian academics from various knowledge areas and research institutions. Productivity was assessed by the ability to submit papers as planned and to meet deadlines during the initial period of social isolation in Brazil. The findings revealed that male academics - especially those without children - are the least affected group, whereas Black women and mothers are the most impacted groups. These impacts are likely a consequence of the well-known unequal division of domestic labor between men and women, which has been exacerbated during the pandemic. Additionally, our results highlight that racism strongly persists in academia, especially against Black women. The pandemic will have long-term effects on the career progression of the most affected groups. The results presented here are crucial for the development of actions and policies that aim to avoid further deepening the gender gap in academia.

Inhibition of pRB Pathway Differentially Modulates Apoptosis in Esophageal Cancer Cells.

Esophageal cancer is the sixth most common cause of cancer-related death worldwide. Current chemotherapy regimens include a combination of 5-fluorouracil (5-FU) and cisplatin, but more efficient therapy strategies are needed to increase 5-year survival. Alterations in the signaling pathway of the tumor suppressor gene Rb-1, which encodes a phosphoprotein (pRB) that negatively regulates the G1/S transition of the cell cycle, are present in 70% of all tumors, but its role in esophageal cancer is still unclear. Most of these are alterations leading to up-regulation of the activity of cyclin-dependent kinases (CDKs) to phosphorylate pRB, which suggests that keeping the wild type pRB phosphorylated might be advantageous. Besides proliferation, pRB also regulates apoptosis induced by tumor necrosis factor-alpha (TNF-α) and DNA-damage. We investigated the status of phosphorylation of pRB along esophageal tumorigenesis stages, as well as whether hyperphosphorylation of pRB could suppress apoptosis induced by cisplatin, 5-FU, or TNF-α in esophageal cancer cells. pRB phosphorylation increased progressively from normal esophageal tissue to metaplasia and adenocarcinoma, suggesting that pRB phosphorylation increases along esophageal tumor stages. When RB-1 was knocked down or CDK inhibitors reduced the levels of phosphorylated pRB, opposite apoptotic effects were observed, depending on the combination of drugs tested: whereas TNF-α- and cisplatin-induced apoptosis increased, 5-FU-induced apoptosis decreased. Taken together, these data suggest that pRB plays a role in esophageal adenocarcinoma and that, depending on the type of anti-cancer treatment, combining CDK inhibitors and chemotherapy has the potential to increase the sensitivity of esophageal cancer cells to cell death.

Involvement of PKA, MAPK/ERK and CaMKII, but not PKC in the acute antidepressant-like effect of memantine in mice.

This study investigated the cellular signaling pathways involved in the acute antidepressant-like action of memantine in the forced swimming test (FST) in mice. The immobility time in the FST was reduced by memantine (3-10 mg/kg, i.p.). The anti-immobility effect of memantine (3 mg/kg, i.p.) was prevented by pretreatment with H-89 (1 microg/site, i.c.v., an inhibitor of PKA), PD098059 (5 microg/site, i.c.v., an inhibitor of MAPK/ERK), KN-62 (1 microg/site, i.c.v., an inhibitor of CaMKII), but not with chelerythrine (1 microg/site, i.c.v., an inhibitor of PKC). Taken together, these results firstly demonstrate that the acute antidepressant-like effect of memantine seems to be dependent on the cellular signaling modulated by PKA, CaMKII and MAPK/ERK, but not by PKC.

In Vivo Endoluminal Ultrasound Biomicroscopy and Endoscopy of Inflamed Rat Esophagus.

The development of high-frequency endoscopic ultrasound for the investigation of models of esophageal disease may offer insights for future translation to human imaging. With respect to small animal models of esophageal diseases, ultrasound imaging instrumentation must employ frequencies scaled up to maintain the compromise between image resolution and inspected region. In this sense, a 40-MHz endoluminal ultrasound biomicroscopy (eUBM) system and an endoscope were tested as diagnostic methods of imaging rat esophageal lesions in the acute and chronic phases caused by sodium hydroxide. Although endoscopy allowed grading of the esophagus in accordance with a classification specific to the epithelial alterations and including hyperemia, edema, exudates, fibrin and superficial and deep ulcerations, the eUBM images yielded the detection of superficial and deep ulcerations, as well as wall alterations caused by edema and inflammatory infiltrate in the submucosa. Additionally, eUBM enabled wall thickness measurements, which were statistically significantly increased (p < 0.05) in the acute phase.

In vivo endoluminal ultrasound biomicroscopic imaging in a mouse model of colorectal cancer.

RATIONALE AND OBJECTIVES: The gold-standard tool for colorectal cancer detection is colonoscopy, but it provides only mucosal surface visualization. Ultrasound biomicroscopy allows a clear delineation of the epithelium and adjacent colonic layers. The aim of this study was to design a system to generate endoluminal ultrasound biomicroscopic images of the mouse colon, in vivo, in an animal model of inflammation-associated colon cancer. MATERIALS AND METHODS: Thirteen mice (Mus musculus) were used. A 40-MHz miniprobe catheter was inserted into the accessory channel of a pediatric flexible bronchofiberscope. Control mice (n = 3) and mice treated with azoxymethane and dextran sulfate sodium (n = 10) were subjected to simultaneous endoluminal ultrasound biomicroscopy and white-light colonoscopy. The diagnosis obtained with endoluminal ultrasound biomicroscopy and colonoscopy was compared and confirmed by postmortem histopathology. RESULTS: Endoluminal ultrasound biomicroscopic images showed all layers of the normal colon and revealed lesions such as lymphoid hyperplasias and colon tumors. Additionally, endoluminal ultrasound biomicroscopy was able to detect two cases of mucosa layer thickening, confirmed by histology. Compared to histologic results, the sensitivities of endoluminal ultrasound biomicroscopy and colonoscopy were 0.95 and 0.83, respectively, and both methods achieved specificities of 1.0. CONCLUSIONS: Endoluminal ultrasound biomicroscopy can be used, in addition to colonoscopy, as a diagnostic method for colonic lesions. Moreover, experimental endoluminal ultrasound biomicroscopy in mouse models is feasible and might be used to further develop research on the differentiation between benign and malignant colonic diseases.

Nuclear expression of ß-catenin promotes RB stability and resistance to TNF-induced apoptosis in colon cancer cells.

Tumor necrosis factor (TNF)-α promotes tumor development under chronic inflammation. Because TNF also activates caspase-8, selective inhibition of TNF-induced extrinsic apoptosis would be required for inflammation-associated tumor growth. In a mouse model of inflammation-associated colon carcinogenesis, we found nuclear expression of ß-catenin in tumors of wild-type, but not mutant, mice that were made resistant to TNF-induced apoptosis by a germline mutation blocking caspase cleavage of the retinoblastoma (RB) protein, despite similar frequencies of ß-catenin exon-3 mutations in these two genetic backgrounds. TNF-induced apoptosis was also attenuated in human colon cancer cell lines with genetically activated ß-catenin. However, we found that HCT116 cells, which contain an activated allele of ß-catenin but do not express nuclear ß-catenin, were sensitive to TNF-induced apoptosis. In HCT116 cells, TNF stimulated efficient RB cleavage that preceded chromatin condensation. In contrast, TNF did not induce RB cleavage in colon cancer cells expressing nuclear ß-catenin and these cells could be sensitized to basal and/or TNF-induced apoptosis by the knockdown of ß-catenin or RB. In the apoptosis-resistant colon cancer cells, knockdown of ß-catenin led to a reduction in the RB protein without affecting RB mRNA. Furthermore, ectopic expression of the caspase-resistant, but not the wild-type, RB re-established resistance to TNF-induced caspase activation in colon cancer cells without ß-catenin. Together, these results suggest that nuclear ß-catenin-dependent RB stabilization suppresses TNF-induced apoptosis in caspase-8-positive colon cancer cells.

Simultaneous follow-up of mouse colon lesions by colonoscopy and endoluminal ultrasound biomicroscopy.

AIM: To evaluate the potential use of colonoscopy and endoluminal ultrasonic biomicroscopy (eUBM) to track the progression of mouse colonic lesions. METHODS: Ten mice were treated with a single azoxymethane intraperitoneal injection (week 1) followed by seven days of a dextran sulfate sodium treatment in their drinking water (week 2) to induce inflammation-associated colon tumors. eUBM was performed simultaneously with colonoscopy at weeks 13, 17-20 and 21. A 3.6-F diameter 40 MHz mini-probe catheter was used for eUBM imaging. The ultrasound mini-probe catheter was inserted into the accessory channel of a pediatric flexible bronchofiberscope, allowing simultaneous acquisition of colonoscopic and eUBM images. During image acquisition, the mice were anesthetized with isoflurane and kept in a supine position over a stainless steel heated surgical waterbed at 37 °C. Both eUBM and colonoscopic images were captured and stored when a lesion was detected by colonoscopy or when the eUBM image revealed a modified colon wall anatomy. During the procedure, the colon was irrigated with water that was injected through a flush port on the mini-probe catheter and that acted as the ultrasound coupling medium between the transducer and the colon wall. Once the acquisition of the last eUBM/colonoscopy section for each animal was completed, the colons were fixed, paraffin-embedded, and stained with hematoxylin and eosin. Colon images acquired at the first time-point for each mouse were compared with subsequent eUBM/colonoscopic images of the same sites obtained in the following acquisitions to evaluate lesion progression. RESULTS: All 10 mice had eUBM and colonoscopic images acquired at week 13 (the first time-point). Two animals died immediately after the first imaging acquisition and, consequently, only 8 mice were subjected to the second eUBM/colonoscopy imaging acquisition (at the second time-point). Due to the advanced stage of colonic tumorigenesis, 5 animals died after the second time-point image acquisition, and thus, only three were subjected to the third eUBM/colonoscopy imaging acquisition (the third time-point). eUBM was able to detect the four layers in healthy segments of colon: the mucosa (the first hyperechoic layer moving away from the mini-probe axis), followed by the muscularis mucosae (hypoechoic), the submucosa (the second hyperechoic layer) and the muscularis externa (the second hypoechoic layer). Hypoechoic regions between the mucosa and the muscularis externa layers represented lymphoid infiltrates, as confirmed by the corresponding histological images. Pedunculated tumors were represented by hyperechoic masses in the mucosa layer. Among the lesions that decreased in size between the first and third time-points, one of the lesions changed from a mucosal hyperplasia with ulceration at the top to a mucosal hyperplasia with lymphoid infiltrate and, finally, to small signs of mucosal hyperplasia and lymphoid infiltrate. In this case, while lesion regression and modification were observable in the eUBM images, colonoscopy was only able to detect the lesion at the first and second time-points, without the capacity to demonstrate the presence of lymphoid infiltrate. Regarding the lesions that increased in size, one of them started as a small elevation in the mucosa layer and progressed to a pedunculated tumor. In this case, while eUBM imaging revealed the lesion at the first time-point, colonoscopy was only able to detect it at the second time-point. All colonic lesions (tumors, lymphoid infiltrate and mucosal thickening) were identified by eUBM, while colonoscopy identified just 76% of them. Colonoscopy identified all of the colonic tumors but failed to diagnose lymphoid infiltrates and increased mucosal thickness and failed to differentiate lymphoid infiltrates from small adenomas. During the observation period, most of the lesions (approximately 67%) increased in size, approximately 14% remained unchanged, and 19% regressed. CONCLUSION: Combining eUBM with colonoscopy improves the diagnosis and the follow-up of mouse colonic lesions, adding transmural assessment of the bowel wall.

Equinatoxin II potentiates temozolomide- and etoposide-induced glioblastoma cell death.

Glioblastoma (GBM) is considered incurable due to its resistance to current cancer treatments. So far, all clinically available alternatives for treating GBM are limited, evoking the development of novel treatment strategies that can more effectively manage these tumors. Extensive effort is being dedicated to characterize the molecular basis of GBM resistance to chemotherapy and to explore novel therapeutic procedures that may improve overall survival. Cytolysins are toxins that form pores in target cell membranes, modifying ion homeostasis and leading to cell death. These pore-forming toxins might be used, therefore, to enhance the efficiency of conventional chemotherapeutic drugs, facilitating their entrance into the cell. In this study, we show that a non-cytotoxic concentration of equinatoxin II (EqTx-II), a pore-forming toxin from the sea anemone Actinia equina, potentiates the cytotoxicity induced by temozolomide (TMZ), a first-line GBM treatment, and by etoposide (VP-16), a second- or third-line GBM treatment. We also suggest that this effect is selective to GBM cells and occurs via PI3K/Akt pathway inhibition. Finally, Magnetic resonance imaging (MRI) revealed that a non-cytotoxic concentration of EqTx-II potentiates the VP-16-induced inhibition of GBM growth in vivo. These combined therapies constitute a new and potentially valuable tool for GBM treatment, leading to the requirement of lower concentrations of chemotherapeutic drugs and possibly reducing, therefore, the adverse effects of chemotherapy.

Features of in vitro ultrasound biomicroscopic imaging and colonoscopy for detection of colon tumor in mice.

The present work tested the capability of ultrasound biomicroscopy (UBM), at 45 MHz, to provide cross-sectional images with appropriate resolution and contrast to detect tumors and determine their penetration depths on the colon of mice, Mus musculus (Linnaeus 1758), treated with carcinogen for colon tumor induction. B-mode images were obtained, in vitro, from each animal (13 treated and 4 untreated) colon opened longitudinally and immersed in saline solution at room temperature. Prior to UBM inspection, all animals were also examined by colonoscopy. The layers of normal colon identified by UBM are: mucosa (hyperechoic), muscularis mucosae (hypoechoic), submucosa (hyperechoic) and muscularis externa (hypoechoic). UBM images of colon lesions presented structures corresponding to tumors (hyperechoic), lymphoid hyperplasia (hypoechoic) and polypoid tumors (hyperechoic). Additionally, tumoral lesion invasion through the colon was also identified. When compared with histopathologic analysis, all colon lesions detected by UBM were confirmed, while colonoscopic findings had two false negatives.

Inhibition of MAPK/ERK, PKC and CaMKII signaling blocks cytolysin-induced human glioma cell death.

BACKGROUND: Cytolysins are pore-forming toxins that show anticancer activity by a mechanism hitherto poorly investigated. MATERIALS AND METHODS: To investigate how cytolysins are cytotoxic to resistant cancer cells, proliferation and cell death were evaluated on U87 glioblastoma cells treated with toxin Bc2 or equinatoxin-II (EqTx-II). RESULTS: Toxins Bc2 and EqTx-II decreased cell viability and increased lactate dehydrogenase (LDH) release in a concentration-dependent manner. Swollen, dead or dying cells were negative for TUNEL staining. The pre-treatment with inhibitors of mitogen-activated/extracellular regulated kinase (MEK1), protein kinase C (PKC) or Ca(2+)/calmodulin-dependent kinase II (CaMKII) blocked the toxic effects of toxin Bc2 and EqTx-II, suggesting that calcium entry, activation of MEK1, PKC and CaMKII pathways are involved in the cytotoxicity induced by these cytolysins. CONCLUSION: Cytolysins were shown to be toxic to glioblastoma cells by activating several intracellular signaling pathways and resulting in necrosis-like cell death.

Peptide gomesin triggers cell death through L-type channel calcium influx, MAPK/ERK, PKC and PI3K signaling and generation of reactive oxygen species.

Gomesin is an antimicrobial peptide isolated from hemocytes of a common Brazilian tarantula spider named Acanthoscurria gomesiana. This peptide exerts antitumor activity in vitro and in vivo by an unknown mechanism. In this study, the cytotoxic mechanism of gomesin in human neuroblastoma SH-SY5Y and rat pheochromocytoma PC12 cells was investigated. Gomesin induced necrotic cell death and was cytotoxic to SH-SY5Y and PC12 cells. The peptide evoked a rapid and transient elevation of intracellular calcium levels in Fluo-4-AM loaded PC12 cells, which was inhibited by nimodipine, an L-type calcium channel blocker. Preincubation with nimodipine also inhibited cell death induced by gomesin in SH-SY5Y and PC12 cells. Gomesin-induced cell death was prevented by the pretreatment with MAPK/ERK, PKC or PI3K inhibitors, but not with PKA inhibitor. In addition, gomesin generated reactive oxygen species (ROS) in SH-SY5Y cells, which were blocked with nimodipine and MAPK/ERK, PKC or PI3K inhibitors. Taken together, these results suggest that gomesin could be a useful anticancer agent, which mechanism of cytotoxicity implicates calcium entry through L-type calcium channels, activation of MAPK/ERK, PKC and PI3K signaling as well as the generation of reactive oxygen species.

Potentiation of anticancer-drug cytotoxicity by sea anemone pore-forming proteins in human glioblastoma cells.

The search for new drugs and treatment approaches is of particular importance for glioblastomas (GBMs), as with other types of malignant gliomas, as they are lethal without the available medical care. Current anticancer cocktails have failed to prolong survival beyond 1 year, in part owing to the natural resistance of GBM cells and to the toxic side effects of the available drugs. In many organisms, cell death can be induced by cytolysins, which are proteins that can form pores in biological membranes. Perhaps by facilitating drugs to enter into the cytosol, cytolysins might be used to increase the efficacy of conventional anticancer agents. Here, the cytotoxicity of two sea anemone pore-forming cytolysins, toxin Bc2, and equinatoxin (EqTx-II) were investigated. Toxin Bc2 and EqTx-II were cytotoxic against human U87 and A172 GBM cell lines either wild type or p53 mutant, a tumor suppressor frequently mutated in malignant gliomas. Moreover, noncytotoxic concentrations of Bc2 or EqTx-II potentiated the cytotoxicity induced by low dose concentrations of all classical chemotherapeutics agents tested: cytosine arabinoside, doxorubicin, and vincristine. In comparison with the cytotoxicity induced by each of these classical anticancer drugs alone, 10-300-fold less of the therapeutic drug was needed when combined with the cytolysins. These results are promising, since lower concentrations of chemotherapeutic drugs could reduce the adverse effects of chemotherapy.