Association between pre-treatment indicators and compliance to neoadjuvant/perioperative chemotherapy in operable gastric cancer

Background and aims: perioperative treatment is currently the gold standard approach for locally advanced gastric cancer (GC). Unfortunately, the phenomenon of patients dropping out of treatment has been frequently observed. The primary aims of this study were to verify if routine blood parameters, the inflammatory response markers, sarcopenia, and the depletion of adipose tissues were associated with compliance with neoadjuvant/perioperative chemotherapy. Methods and study design: sarcopenia and adipose indices were calculated with a CT scan before starting chemotherapy and before surgery. Blood samples were considered before the first and second cycles of chemotherapy. Results: A total of 84 patients with localized operable GC, were identified between September 2010 and January 2021. Forty-four patients (52.4%) did not complete the treatment according to the number of cycles planned/performed. Eight patients (9.5%) decided to suspend chemotherapy, seven patients (8.3%) discontinued because of clinical decision-making, 14 patients (16.7%) because of toxicity, and 15 patients (17.9%) for miscellaneous causes. Sarcopenia before starting chemotherapy was found to be present in 38 patients (50.7%) while it was in 47 patients (60%) at the CT scan before the gastrectomy. In multivariable analysis, both for changes tending to have a value of PLR at basal and in the second control a higher one than the cut-off (OR = 5.03, 95% CI: 1.34 - 18.89, p-value = 0.017), and for PLR which increased from a lower to a higher value in second control with respect to the cut off (OR = 4.64, 95% CI: 1.02 -21.02, p-value = 0.047) resulted associated with incomplete compliance. Conclusions: among the biological indicators, changes in the value of PLR with a tendency towards increasing compared to the cut-off appear to be an immediate indicator of incomplete compliance with neoadjuvant/perioperative treatment. More information is needed to reduce the causes of interruption.

Advanced studies on two animal models, murine and fish. RadKI21A626T mouse model: new insights into molecular mechanisms of enteric neuro-epithelial pathology. European sea bass: study of the effects of essential oils in different diets on the gastric system.

My PhD research period was focused on the anatomical, physiological and functional study of the gastrointestinal system on two different animal models. In two different contexts, the purpose of these two lines of research was contribute to understand how a specific genetic mutation or the adoption of a particular dietary supplement can affect gastrointestinal function. Functional gastrointestinal disorders are chronic conditions characterized by symptoms for which no organic cause can be found. Although symptoms are generally mild, a small subset of cases shows severe manifestations. This subset of patients may also have recurrent intestinal sub-occlusive episodes, but in absence of mechanical causes. This condition is referred to as chronic intestinal pseudo-obstruction, a rare, intractable chronic disease. Some mutations have been associated with CIPO. A novel causative RAD21 missense mutation was identified in a large consanguineous family, segregating a recessive form of CIPO. The present thesis was aimed to elucidate the mechanisms leading to neuropathy underlying CIPO via a recently developed conditional KI mouse carrying the RAD21 mutation. The experimental studies are based on the characterization and functional analysis of the conditional KI Rad21A626T mouse model. On the other hand aquaculture is increasing the global supply of foods. The species selected and feeds used affects the nutrients available from aquaculture, with a need to improve feed efficiency, both for economic and environmental reasons, but this will require novel innovative approaches. Nutritional strategies focused on the use of botanicals have attracted interest in animal production. Previous research indicates the positive results of using essential oils (EOs) as natural feed additives for several farmed animals. Therefore, the present study was designed to compare the effects of feed EO supplementation in two different forms (natural and composed of active ingredients obtained by synthesis) on the gastric mucosa in European sea bass.

Targeting epigenetic mechanisms in gastric cancer

Gastric cancer (GC) is a hard challenge for medical oncology, with globally over one million of new diagnoses each year and low survival rates. Gastric carcinogenesis is guided by the interaction of several risk factors, exerting through sequential histopathologic steps, including chronic gastritis, atrophic gastritis, intestinal metaplasia, dysplasia and cancer. GC is classified on the basis of anatomical, histological or molecular classification, reflecting the wide cancer heterogeneity, also highlighted by the inefficacy of the actual treatment schedules. Epigenetic mechanisms alterations affecting DNA methylation, histone methylation and acetylation, are a recognized hallmark of cancer and stand at the basis of gastric carcinogenesis and tumor development. The pharmacological targeting of these altered mechanisms is an attractive option for new cancer treatments. Aim of this study was to test the therapeutic potential of the compound CM-272 for GC, a selective and strong dual inhibitor of DNMT1 and EHMT2, which reached important results in pre-clinical models of other gastrointestinal malignancies. Moreover, in a GC patients case series, the expression of the target of the compound was tested, to prove the rationale for inhibition of DNMT1, EHMT2 and their functional adaptor were over-expressed in the majority of GC patients tissues. Through in-vitro testing of CM-272 alone and in combination with the most used chemotherapeutic treatments for GC in a panel of GC cell lines, this study demonstrated that the compound has a strong ability in inhibiting GC cells growth. Even though not directly inducing apoptosis, CM-272 was able to induce a senescent phenotype in GC cells, and to epigenetically reprogram the transcription of genes involved in phosphorylation cascades and mitochondria metabolism, thus affecting the growth and energetic machinery of cancer cells. In conclusion, the pharmacological targeting of epigenetic mechanisms demonstrated good potential pre-clinical models of GC, and further investigations to test in-vivo efficacy are needed.

EBV Type II latency relies on PARP1 activity and is essential for gastric epithelial cell transformation in EBV-associated Gastric Cancer (EBVaGC)

Epstein-Barr virus (EBV) establishes a lifelong asymptomatic infection by replicating its chromatinized genome, called episome, together with the host genome. EBV exhibits different latency-associated transcriptional repertoires that mirror its three-dimensional structures of the genome. CTCF, Cohesin and PARP1 are involved in maintaining viral latency and establishing episome architecture. Epstein-Barr virus-associated gastric cancer (EBVaGC) represents almost 10% of all gastric cancers globally. EBVaGC exhibit an intermediate viral transcription profile known as "Latency II", expressing specific viral genes and non-coding RNAs. In this study, we investigated the impact of PARP1 inhibition on CTCF/Cohesin binding in Type II latency. We observed a destabilization of the binding of both factors, leading to a disrupted three-dimensional architecture of the episomes and consequently, an altered viral gene expression. Despite sharing the same CTCF binding profile, Type I, II, and III latencies display different 3D episomal structures that correlate with variations in viral gene expression. Additionally, our analysis of H3K27ac-enriched chromatin interactions revealed differences between Type II latency episomes and a link to cellular transformation through docking of the EBV episomes at specific sites of the Human genome, thus promoting oncogene expression. Overall, this work provides insights into the role of PARP1 in maintaining active latency and novel mechanisms of EBV-induced cellular transformation.