The paradox of Bcl-2: How does paclitaxel convert Bcl-2 function from antiapoptotic to proapoptotic?

Bcl-2 is an antiapoptotic protein often overexpressed in human cancer and exerts an antiapoptotic function at mitochondrial level, through the opening suppression of the permeability transition pore complex (PTPC). This process prevents the consequent leakage of mitochondrial transmembrane potential and effluxing from mitochondria of proapoptotic factors such as Cytochrome C, AIF and APAF-1. Recently, in ovarian cancer cells paclitaxel (PTX)-resistance has been associated to downregulation of Bcl-2. In order to investigate this paradox, human Bcl-2 was stably transfected in PTX-resistant ovarian cancer cells and mitochondria were isolated from these cells. Mitochondria prepared from untransfected control cells showed undetectable levels of Bcl-2 and PTX was unable to modulate the opening of PTPC, as demonstrated by the uptake of the cationic fluorochrome Rhodamine 123. In the same cells transfected with Bcl-2, sensitivity to paclitaxel was restored and the drug was able to induce the opening of PTPC and the leakage of mitochondrial transmembrane potential. Among Bcl-2 family members, the peculiar difference of Bcl-2 consists in the disordered loop domain. Therefore, we prepared stable Bcl-2 transformed cells with a construct devoid of the loop domain (Bcl-2-Δ). In mitochondria prepared from these cells, PTX was unable to modulate the opening of PTPC. These findings suggest that the disordered loop of Bcl-2 is involved in the PTX binding, but did not clarify if this occurs in a direct or indirect way, with the involvement of other proteins. In order to address this issue, we used plasmon resonance-based optical biosensor technology. In vitro Bcl-2 and Bcl-2-Δ translated proteins were immobilised on a optical biochip to permit a real time monitoring of the potential binding of paclitaxel to Bcl-2. The experimental output pointed out that PTX directly binds to Bcl-2, and not to Bcl-2-Δ, this signaling that the PTX binding site is located within the disordered loop domain of the protein. With the aim of better understanding the binding mechanism, we performed molecular modelling investigations, taking as template the experimentally determined structure of class I beta-tubulin in complex with PTX. Results indicated that the putative binding site of PTX in the disordered loop domain is indeed very similar to that present in beta tubulin. In beta-tubulin PTX binds to a pocket with strong interactions with His229, Pro360-Pro359 and the sequence Arg278-Ser277-Thr276-Leu275-Pro274. Similar interactions were found in our paclitaxel/Bcl-2 docked complex: His58, Pro39-Pro40 and the sequence Thr69-Arg68-Ala-67-Val66-Pro65. Due to the similarity in the binding, it is likely that PTX is a peptide-mimicking structure with a structure similar to endogenous agonist(s) able to bind to both beta-tubulin and Bcl-2, and consequently transferring a death signal from microtubules to mitochondria

HPV Vaccination in Women with Cervical Intraepithelial Neoplasia Undergoing Excisional Treatment: Insights into Unsolved Questions

Several questions regarding the role of vaccination in women treated for high-grade cervical intraepithelial lesion (HSIL) have not been clarified. One of the main queries is whether the time at which the vaccine is administered (before or after treatment) influences the protection against post-treatment HSIL. A second unanswered question is whether the vaccine has any effect in women with persistent HPV after treatment. We aimed to address these questions in a study of 398 women undergoing excisional treatment from July 2016 to December 2019. Vaccination was funded and offered to all women undergoing treatment. A total of 306 women (76.9%) accepted HPV vaccination (vaccinated group): 113 (36.9%) received the first dose before excision and 193 (63.1%) after the procedure. A total of 92 women (23.1%) refused the vaccine (non-vaccinated group). Women vaccinated before treatment showed a lower rate of post-treatment HSIL compared with non-vaccinated women (0.9% vs. 6.5%; p = 0.047). Among women with persistent HPV infection after treatment, those who had received the vaccine showed a lower prevalence of post-treatment HSIL than non-vaccinated women (2.6% vs. 10.5%; p = 0.043). In conclusion, this study shows that HPV vaccination before treatment reduces the prevalence of post-treatment HSIL and suggests that vaccination might even benefit women with persistent HPV after treatment

Penile Squamous Cell Carcinomas in Sub-Saharan Africa and Europe: Differential Etiopathogenesis

Penile squamous cell carcinomas (PSCC) are classified by the World Health Organization into two categories based on their relationship with the human papillomavirus (HPV): HPV-associated and HPV-independent. We compared a cohort of PSCC from Mozambique, a sub-Saharan country in southeast Africa with a high prevalence of HPV and HIV infection, and Spain, a country in southwestern Europe with a low prevalence of HPV and HIV, to study the distribution of the etiopathogenic categories of these tumors in both sites. A total of 79 PSCC were included in the study (28 from Mozambique and 51 from Spain). All cases underwent HPV-DNA polymerase chain reaction (PCR) testing, genotyping, and immunohistochemistry for p16 and p53. Any PSCC showing either p16 overexpression or HPV-DNA in PCR analysis was considered HPV-associated. Overall, 40/79 (50.6%) tumors were classified as HPV-associated and 39 (49.4%) as HPV-independent. The two sites showed marked differences: 25/28 (89.3%) tumors from Mozambique and only 15/51 (29.4%) from Spain were HPV-associated (p p = 0.8). On average, patients from Mozambique were almost two decades younger than those from Spain (mean age 50.9 ± 14.9 and 69.2 ± 13.3, respectively [p < 0.001]). In conclusion, significant etiopathogenic differences between PSCC in Mozambique and Spain were observed, with a remarkably high prevalence of HPV-associated tumors in Mozambique and a relatively low prevalence in Spain. These data may have important consequences for primary prevention of PSCC worldwide

Pest sensitization to cockroach, mouse, and rat: An Italian multicenter study

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Autism Spectrum Disorder from the Womb to Adulthood: Suggestions for a Paradigm Shift

The wide spectrum of unique needs and strengths of Autism Spectrum Disorders (ASD) is a challenge for the worldwide healthcare system. With the plethora of information from research, a common thread is required to conceptualize an exhaustive pathogenetic paradigm. The epidemiological and clinical findings in ASD cannot be explained by the traditional linear genetic model, hence the need to move towards a more fluid conception, integrating genetics, environment, and epigenetics as a whole. The embryo-fetal period and the first two years of life (the so-called &lsquo;First 1000 Days&rsquo;) are the crucial time window for neurodevelopment. In particular, the interplay and the vicious loop between immune activation, gut dysbiosis, and mitochondrial impairment/oxidative stress significantly affects neurodevelopment during pregnancy and undermines the health of ASD people throughout life. Consequently, the most effective intervention in ASD is expected by primary prevention aimed at pregnancy and at early control of the main effector molecular pathways. We will reason here on a comprehensive and exhaustive pathogenetic paradigm in ASD, viewed not just as a theoretical issue, but as a tool to provide suggestions for effective preventive strategies and personalized, dynamic (from womb to adulthood), systemic, and interdisciplinary healthcare approach