Breaking the Mucin Barrier: A New Affinity Chromatography-Mass Spectrometry Approach to Unveil Potential Cell Markers and Pathways Altered in Pseudomyxoma Peritonei.

BACKGROUND: Pseudomyxoma peritonei (PMP) is a rare peritoneal mucinous carcinomatosis with largely unknown underlying molecular mechanisms. Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy is the only therapeutic option; however, despite its use, recurrence with a fatal outcome is common. The lack of molecular characterisation of PMP and other mucinous tumours is mainly due to the physicochemical properties of mucin. RESULTS: This manuscript describes the first protocol capable of breaking the mucin barrier and isolating proteins from mucinous tumours. Briefly, mucinous tumour samples were homogenised and subjected to liquid chromatography using two specific columns to reduce mainly glycoproteins, albumins and immunoglobulin G. The protein fractions were then subjected to mass spectrometry analysis and the proteomic profile obtained was analysed using various bioinformatic tools. Thus, we present here the first proteome analysed in PMP and identified a distinct mucin isoform profile in soft compared to hard mucin tumour tissues as well as key biological processes/pathways altered in mucinous tumours. Importantly, this protocol also allowed us to identify MUC13 as a potential tumour cell marker in PMP. CONCLUSIONS: In sum, our results demonstrate that this protein isolation protocol from mucin will have a high impact, allowing the oncology research community to more rapidly advance in the knowledge of PMP and other mucinous neoplasms, as well as develop new and effective therapeutic strategies.

Laparoscopic versus open approach for interval cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) in advanced epithelial ovarian cancer: a matched comparative study.

BACKGROUND: The use of the laparoscopic approach for the treatment of carcinomatosis from epithelial ovarian cancer (EOC) is controversial. The aim of this study was to compare the short-term outcomes of both laparoscopic and open approach for interval CRS+HIPEC in a matched cohort of patients with advanced EOC. METHODS: A retrospective analysis of a prospectively maintained database including 254 patients treated with interval CRS-HIPEC between January 2016 and December 2021 was performed. Patients with primary disease and limited carcinomatosis (PCI ≤ 10) were selected. A comparative analysis of patients treated by either open (O-CRS-HIPEC) or the laparoscopic (L-CRS-HIPEC) approach was conducted. Overall survival (OS), disease-free survival (DFS), and perioperative outcomes were analysed. RESULTS: Fifty-three patients were finally selected and enrolled into two comparable groups in this study. Of these, 14 patients were treated by interval L-CRS-HIPEC and 39 by interval O-CRS-HIPEC. The L-CRS-HIPEC group had a shorter hospital stay (5.6 ± 1.9 vs. 9.7 ± 9.8 days; p < 0.001) and a shorter time to return to systemic chemotherapy (4.3 ± 1.9 vs. 10.3 ± 16.8 weeks; p = 0.003). There were no significant differences in postoperative complications between both groups. The 2-year OS and DFS was 100% and 62% in the L-CRS-HIPEC group versus 92% and 60% in the O-CRS-HIPEC group, respectively (p = 0.96; p = 0.786). CONCLUSION: This study suggests that the use of interval L-CRS-HIPEC for primary advanced EOC is associated with shorter hospital stay and return to systemic treatment while obtaining similar oncological results compared to the open approach. Further prospective research is needed to recommend this new approach for these strictly selected patients.

Learning curve for minimal invasive cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) procedures.

PURPOSE: The benefits of the minimally invasive approach for performing cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy (L-CRS + HIPEC) have been described previously, associating an early recovery with similar oncologic outcomes in patients with limited peritoneal carcinomatosis. Currently, no studies are focusing on the learning curve for this emerging procedure. This study aimed to evaluate the L-CRS + HIPEC learning curve and its knock-on effect on the perioperative outcomes. METHODS: We identified all consecutive unselected patients who underwent L-CRS + HIPEC by a single surgeon between April 2016 and January 2022 (n = 51). Patients who underwent risk-reducing CRS + HIPEC (PCI = 0) or initial conversion due to an intraoperative PCI > 10 were excluded from the final analysis. To evaluate the learning curve, perioperative data were analysed using the cumulative sum (CUSUM) analysis. RESULTS: Twenty-six patients were included in the final analysis. Major morbidity occurred in one patient (3.8%). The difficulty of the L-CRS + HIPEC procedures was categorised as low in 23.1% (n = 6), intermediate in 19.2% (n = 5), and advanced in 57.7% (n = 15). The mean length of hospital stay was 5.4 ± 1.5 days. No patient had a conversion to open surgery. The learning curve was divided into two distinct phases: the learning phase (1-14) and the consolidation phase (15-26). A significant decrease in the operative time (375 ± 103.1 vs 239.2 ± 63.6 min) was observed with no differences in complexity, the number of peritonectomy procedures, or morbidity. CONCLUSION: L-CRS + HIPEC is a complex procedure that must be performed in a high-volume and experienced oncologic unit, requiring a learning curve to achieve the consolidation condition, which could be established after 14 procedures.

Intraoperative metabolic changes associated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

BACKGROUND: Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) causes considerable hemodynamic, respiratory, and metabolic changes during the perioperative period. OBJECTIVES: To evaluate metabolic changes associated with this procedure. Understanding perioperative factors and their association with morbidity may improve the perioperative management of patients undergoing this treatment. METHODS: A retrospective review of a prospectively maintained database was performed. All consecutive unselected patients who underwent CRS plus HIPEC between January 2018 and December 2020 (n = 219) were included. RESULTS: The mean age was 58 ± 11.7 years and 167 (76.3%) were female. The most frequent histology diagnosis was serous ovarian carcinoma 49.3% (n = 108) and colon carcinoma 36.1% (n = 79). Mean peritoneal cancer index was 14.07 ± 10.47. There were significant variations in pH, lactic acid, sodium, potassium, glycemia, bicarbonate, excess bases, and temperature (p < 0.05) between the pre-HIPEC and post-HIPEC periods. The closed HIPEC technique resulted in higher levels of temperature than the open technique (p < 0.05). Age, potassium level post-HIPEC potassium level, and pre-HIPEC glycemia were identified as prognostic factors for morbidity in multivariate analysis. CONCLUSION: The administration of HIPEC after CRS causes significant changes in internal homeostasis. Although the closed technique causes a greater increase in temperature, it is not related to higher morbidity rates. The patient's age, post-HIPEC potassium level, and pre-HIPEC glycemia are predictive factors for morbidity.

A Proposal for Modification of the PSOGI Classification According to the Ki-67 Proliferation Index in Pseudomyxoma Peritonei.

BACKGROUND: Pseudomyxoma peritonei (PMP) is a rare malignancy, classified according to the Peritoneal Surface Oncology Group International (PSOGI) classification, whose response to treatment remains highly heterogeneous within the high-grade (HG) category. Molecular profiling of PMP cases might help to better categorize patients and predict treatment responses. METHODS: We studied the Ki-67 proliferation rate and P53 overexpression in tissue samples from our historical cohort of HG-PMP patients. We established as cut-off levels the third quartile of each marker to perform univariate and multivariate Cox regression survival analyses. According to these results, the HG-PMP category was divided into subcategories and a new survival analysis was performed. RESULTS: A total of 90/117 patients with PMP undergoing cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) were selected for secondary analysis. The survival analysis of the HG-PMP category for preoperative variables showed that a proliferation index defined by Ki-67 >15% is a bad prognostic factor, with a hazard ratio (HR) of 3.20 (95% confidence interval [CI] 1.24-8.25). Accordingly, the HG-PMP group was divided using the Ki-67 15% cut-off. The new PSOGI/Ki-67 variable was an independent prognostic factor for overall survival (OS), with an HR of 3.74 (95% CI 1.88-7.47), and disease-free survival (DFS), with an HR of 4.184 (95% CI 1.79-9.75). The estimated 5-year OS rate was 100%, 70% and 24% for the LG-PMP, HG-PMP ≤15% and HG-PMP >15% groups, respectively (p = 0.0001), while the 5-year DFS rate was 90%, 44% and 0%, respectively (p = 0.0001). CONCLUSION: Division of the HG-PMP category of the PSOGI classification, according to the Ki-67 proliferation index, provides two well-defined subcategories, with significant differences in terms of OS and DFS, and hence high prognostic value.

Congenital ablation of Tacr2 reveals overlapping and redundant roles of NK2R signaling in the control of reproductive axis.

Tachykinin (TAC) signaling is an important element in the central control of reproduction. TAC family is mainly composed of substance P (SP), neurokinin A (NKA), and NKB, which bind preferentially to NK1, NK2, and NK3 receptors, respectively. While most studies have focused on the reproductive functions of NKB/NK3R, and to a lesser extent SP/NK1R, the relevance of NK2R, encoded by Tacr2, remains poorly characterized. Here, we address the physiological roles of NK2R in regulating the reproductive axis by characterizing a novel mouse line with congenital ablation of Tacr2. Activation of NK2R evoked acute luteinizing hormone (LH) responses in control mice, similar to those of agonists of NK1R and NK3R. Despite the absence of NK2R, Tacr2-/- mice displayed only partially reduced LH responses to an NK2R agonist, which, nonetheless, were abrogated after blockade of NK3R in Tacr2-/- males. While Tacr2-/- mice displayed normal pubertal timing, LH pulsatility was partially altered in Tacr2-/- females in adulthood, with suppression of basal LH levels, but no changes in the number of LH pulses. In addition, trends for increase in breeding intervals were detected in Tacr2-/- mice. However, null animals of both sexes were fertile, with no changes in estrous cyclicity or sex preference in social behavioral tests. In conclusion, stimulation of NK2R elicited LH responses in mice, while congenital ablation of Tacr2 partially suppressed basal and stimulated LH secretion, with moderate reproductive impact. Our data support a modest, albeit detectable, role of NK2R in the control of the gonadotropic axis, with partially overlapping and redundant functions with other tachykinin receptors.NEW & NOTEWORTHY We have explored here the impact of congenital ablation of the gene (Tacr2) encoding the tachykinin receptor, NK2R, in terms of neuroendocrine control of the reproductive axis, using a novel Tacr2 KO mouse line. Our data support a modest, albeit detectable, role of NK2R in the control of the gonadotropic axis, with partially overlapping and redundant functions with other tachykinin receptors.

From the Ronnett to the PSOGI Classification System for Pseudomyxoma Peritonei: A Validation Study.

BACKGROUND: Several classifications have been used for pseudomyxoma peritonei (PMP), and among these, the Ronnett classification is the most commonly used. However, a new consensual Peritoneal Surface Oncology Group International (PSOGI) classification has recently been proposed. Nonetheless, to date, the ability of the PSOGI classification to predict survival based on its different disease histologic categories has not been validated. METHODS: This study enrolled 117 patients with PMP who had undergone cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) between 1997 and 2020. Cox proportional hazards regression models and time-dependent curve receiver operating characteristic (ROC) analyses were used to assess the predictive capacity of both classification systems for the overall survival (OS) and disease-free survival (DFS) of these patients. RESULTS: Significant differences in the 5-year OS rate were found for the different histologic grades according to each of the classifications. The completeness of cytoreduction score (CCS) was identified as a factor that predicted patient OS prognosis (p = 0.006). According to the time-dependent ROC curves at the "100" time point, adjusted by the CCS and DFS, the capacity to predict OS was optimal and achieved an area under the curve (AUC) of about 69% for OS and approximately 62% for DFS. CONCLUSIONS: Both the Ronnett and PSOGI classifications were able to predict survival optimally for this patient cohort. However, when the classifications were adjusted by the CCS, the predictive availability for OS was better with the PSOGI classification than with the Ronnett classification.

Physical comorbidities as a marker for high risk of psychological distress in cancer patients.

AIMS: Physical and psychiatric comorbidities are common in cancer patients and could impact their treatment and prognosis. However, the evidence base regarding the influence of comorbidities in the management and health service use of patients is still scant. In this research we investigated how physical comorbidities are related to the mental health and help-seeking of cancer patients. METHODS: Data were obtained from the representative National Health Survey of Spain (2017). Participants were respondents who reported a cancer diagnosis (n = 484). These were also matched with controls without cancer history (n = 484) based on age, gender, and region. Four alternative physical comorbidities indices were created based on information regarding 28 chronic conditions. Outcomes of interest were psychological distress and having consulted a mental healthcare professional in the year before the survey. RESULTS: Thirty percent of cancer patients reported significant psychological distress but only 10% had consulted a professional. After adjusting for sociodemographic variables, among cancer patients each additional comorbidity was associated with 9% higher odds of reporting high psychological distress (odds ratio [OR] = 1.09, 95% confidence interval [CI]: 1.01-1.16) and 21% higher odds of having consulted a mental healthcare professional (OR = 1.21, 95% CI: 1.09-1.34). The effects of comorbidities depended on the type of index and were different in controls without cancer history. CONCLUSION: Physical comorbidities in cancer patients are associated with higher risk of psychological distress and higher demand for mental health services. We encourage further research on this issue as it could improve mental health screening and management in oncologic care.

Deregulation of miR-324/KISS1/kisspeptin in early ectopic pregnancy: mechanistic findings with clinical and diagnostic implications.

BACKGROUND: Ectopic pregnancy is a life-threatening condition for which novel screening tools that would enable early accurate diagnosis would improve clinical outcomes. Kisspeptins, encoded by KISS1, play an essential role in human reproduction, at least partially by regulating placental function and possibly embryo implantation. Kisspeptin levels are elevated massively in normal pregnancy and reportedly altered in various gestational pathologic diseases. Yet, the pathophysiologic role of KISS1/kisspeptin in ectopic pregnancy has not been investigated previously. OBJECTIVE: The purpose of this study was to evaluate changes of KISS1/kisspeptin levels in ectopic pregnancy and their underlaying molecular mechanisms and to ascertain the diagnostic implications of these changes. STUDY DESIGN: A total of 122 women with normal pregnancy who underwent voluntary termination of pregnancy and 84 patients who experienced tubal ectopic pregnancy were recruited. Measurements of plasma kisspeptins and KISS1 expression analyses in human embryonic/placental tissue were conducted in ectopic pregnancy and voluntary termination of pregnancy control subjects during the early gestational window (<12 weeks). Putative microRNA regulators of KISS1 were predicted in silico, followed by expression analyses of selected microRNAs and validation of repressive interactions in vitro. Circulating levels of these microRNAs were also assayed in ectopic pregnancy vs voluntary termination of pregnancy. RESULTS: Circulating kisspeptins gradually increased during the first trimester of normal pregnancy but were reduced markedly in ectopic pregnancy. This profile correlated with the expression levels of KISS1 in human embryonic/placental tissue, which increased in voluntary termination of pregnancy but remained suppressed in ectopic pregnancy. Bioinformatic predictions and expression analyses identified miR-27b-3p and miR-324-3p as putative repressors of KISS1 in human embryonic/placental tissue at <12 weeks gestation, when expression of microRNAs was low in voluntary termination of pregnancy control subjects but significantly increased in ectopic pregnancy. Yet, a significant repressive interaction was documented only for miR-324-3p, occurring at the predicted 3'-UTR of KISS1. Interestingly, circulating levels of miR-324-3p, but not of miR-27b-3p, were suppressed distinctly in ectopic pregnancy, despite elevated tissue expression of the pre-microRNA. A decision-tree model that used kisspeptin and miR-324-3p levels was successful in discriminating ectopic pregnancy vs voluntary termination of pregnancy, with a receiver-operating characteristic area under the curve of 0.95±0.02 (95% confidence interval). CONCLUSION: Our results document a significant down-regulation of KISS1/kisspeptins in early stages of ectopic pregnancy via, at least partially, a repressive interaction with miR-324-3p. Our data identify circulating kisspeptins and miR-324-3p as putative biomarkers for accurate screening of ectopic pregnancy at early gestational ages.

Identification of candidate biomarkers for hepatocellular carcinoma in plasma of HCV-infected cirrhotic patients by 2-D DIGE.

BACKGROUND: The current methods available for screening and detecting hepatocellular carcinoma (HCC) have insufficient sensitivity and specificity, and only a low percentage of diagnosis of small tumours is based on these assays. Because HCC is usually asymptomatic at potentially curative stages, identification of biomarkers for the early detection of HCC is essential to improve patient survival. AIM: The aim of this study was to identify candidate markers for HCC development in the plasma from hepatitis C virus (HCV)-infected cirrhotic patients. METHODS: We compared protein expression profiles of plasma samples from HCV-infected cirrhotic patients with and without HCC, using two-dimensional fluorescence difference gel electrophoresis (2-D DIGE) coupled with MALDI-TOF/TOF mass spectrometry. The 2-D DIGE results were analysed statistically using Decyder™ software, and verified by western blot and enzyme-linked immunosorbent assay (ELISA). RESULTS: In the plasma of HCV-infected HCC patients, we observed decreased expression of complement component 9, ficolin-3 (FCN3), serum amyloid P component (SAP), fibrinogen-gamma and immunoglobulin gamma-1 chain, and increased expression of vitronectin (VTN) and galectin-3 binding protein (G3BP) by DIGE analysis. ELISA confirmed DIGE results for VTN and G3BP but not for SAP or FCN3 in a larger patient population. CONCLUSIONS: The proteins VTN and SAP are candidate biomarkers for HCC development in HCV-infected cirrhotic patients.

Kisspeptin signaling in astrocytes modulates the reproductive axis.

Reproduction is safeguarded by multiple, often cooperative regulatory networks. Kisspeptin signaling, via KISS1R, plays a fundamental role in reproductive control, primarily by regulation of hypothalamic GnRH neurons. We disclose herein a pathway for direct kisspeptin actions in astrocytes that contributes to central reproductive modulation. Protein-protein-interaction and ontology analyses of hypothalamic proteomic profiles after kisspeptin stimulation revealed that glial/astrocyte markers are regulated by kisspeptin in mice. This glial-kisspeptin pathway was validated by the demonstrated expression of Kiss1r in mouse astrocytes in vivo and astrocyte cultures from humans, rats and mice, where kisspeptin activated canonical intracellular signaling-pathways. Cellular co-expression of Kiss1r with the astrocyte markers, GFAP and S100-ß, occurred in different brain regions, with higher percentage in Kiss1- and GnRH-enriched areas. Conditional ablation of Kiss1r in GFAP-positive cells, in the G-KiRKO mouse, altered gene expression of key factors in PGE2 synthesis in astrocytes, and perturbed astrocyte-GnRH neuronal appositions, as well as LH responses to kisspeptin and LH pulsatility, as surrogate marker of GnRH secretion. G-KiRKO mice also displayed changes in reproductive responses to metabolic stress induced by high-fat diet, affecting female pubertal onset, estrous cyclicity and LH-secretory profiles. Our data unveil a non-neuronal pathway for kisspeptin actions in astrocytes, which cooperates in fine-tuning the reproductive axis and its responses to metabolic stress.

Spliceosomic dysregulation in pancreatic cancer uncovers splicing factors PRPF8 and RBMX as novel candidate actionable targets.

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal cancer, characterized by late diagnosis and poor treatment response. Surgery is the only curative approach, only available to early-diagnosed patients. Current therapies have limited effects, cause severe toxicities, and minimally improve overall survival. Understanding of splicing machinery alterations in PDAC remains incomplete. Here, we comprehensively examined 59 splicing machinery components, uncovering dysregulation in pre-mRNA processing factor 8 (PRPF8) and RNA-binding motif protein X-linked (RBMX). Their downregulated expression was linked to poor prognosis and malignancy features, including tumor stage, invasion and metastasis, and associated with poorer survival and the mutation of key PDAC genes. Experimental modulation of these splicing factors in pancreatic cancer cell lines reverted their expression to non-tumor levels and resulted in decreased key tumor-related features. These results provide evidence that the splicing machinery is altered in PDAC, wherein PRPF8 and RBMX emerge as candidate actionable therapeutic targets.

Prolyl hydroxylase-dependent modulation of eukaryotic elongation factor 2 activity and protein translation under acute hypoxia.

Early adaptive responses to hypoxia are essential for cell survival, but their nature and underlying mechanisms are poorly known. We have studied the post-transcriptional changes in the proteome of mammalian cells elicited by acute hypoxia and found that phosphorylation of eukaryotic elongation factor 2 (eEF2), a ribosomal translocase whose phosphorylation inhibits protein synthesis, is under the precise and reversible control of O(2) tension. Upon exposure to hypoxia, phosphorylation of eEF2 at Thr(56) occurred rapidly (<15 min) and resulted in modest translational arrest, a fundamental homeostatic response to hypoxia that spares ATP and thus facilitates cell survival. Acute inhibitory eEF2 phosphorylation occurred without ATP depletion or AMP kinase activation. Furthermore, eEF2 phosphorylation was mimicked by prolyl hydroxylase (PHD) inhibition with dimethyloxalylglycine or by selective PHD2 siRNA silencing but was independent of hypoxia-inducible factor α stabilization. Moreover, overexpression of PHD2 blocked hypoxic accumulation of phosphorylated eEF2. Therefore, our findings suggest that eEF2 phosphorylation status (and, as a consequence, translation rate) is controlled by PHD2 activity. They unravel a novel pathway for cell adaptation to hypoxia that could have pathophysiologic relevance in tissue ischemia and cancer.

Characterization of the reproductive effects of the Vgf-derived peptide TLQP-21 in female rats: in vivo and in vitro studies.

BACKGROUND: VGF (non-acronymic), a protein expressed in the hypothalamus and pituitary, is involved in the control of metabolism and body weight homeostasis. Different active peptide fragments are generated from VGF, including TLQP-21. Previous studies of our group reported that this molecule participates also in the regulation of reproductive function in male rats, with predominant stimulatory effects. METHODS: We report herein a series of studies on the reproductive effects of TLQP-21 in female rats, as evaluated by a combination of in vivo and in vitro analyses. RESULTS: TLQP-21 modestly increased serum LH levels after systemic administration and directly stimulated pituitary LH and FSH secretion in prepubertal female rats, while acute central injection of TLQP-21 was unable to modify LH secretion at this age. Repeated central administration of TLQP-21 during the pubertal transition (between PND-28 and -35) to female rats fed ad libitum advanced the timing of vaginal opening and increased the percentage of animals with signs of ovulation. Moreover, an analogous treatment slightly enhanced ovarian maturation in pubertal female rats subjected to chronic undernutrition, but was unable to rescue the delay of vaginal opening induced by food deprivation. In addition, TLQP-21 oppositely modified LH secretion in adult female rats depending on the stage of the ovarian cycle: it stimulated LH secretion when injected in the morning of diestrus and decreased the magnitude of the preovulatory LH (but not FSH) surge when injected in the afternoon of proestrus. CONCLUSIONS: Our data are the first to document the potential involvement of TLQP-21 in the control of reproductive function in female rats.

Intraoperative oxygen tension and redox homeostasis in Pseudomyxoma peritonei: A short case series.

Introduction: Pseudomyxoma peritonei (PMP) is a rare malignant disease characterized by a massive multifocal accumulation of mucin within the peritoneal cavity. The current treatment option is based on complete cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy. However, the recurrence is frequent with subsequent progression and death. To date, most of the studies published in PMP are related to histological and genomic analyses. Thus, the need for further studies unveiling the underlying PMP molecular mechanisms is urgent. In this regard, hypoxia and oxidative stress have been extensively related to tumoral pathologies, although their contribution to PMP has not been elucidated. Methods: In this manuscript, we have evaluated, for the first time, the intratumoral real-time oxygen microtension (pO2mt) in the tumor (soft and hard mucin) and surrounding healthy tissue from five PMP patients during surgery. In addition, we measured hypoxia (Hypoxia Inducible Factor-1a; HIF-1α) and oxidative stress (catalase; CAT) markers in soft and hard mucin from the same five PMP patient samples and in five control samples. Results: The results showed low intratumoral oxygen levels, which were associated with increased HIF-1α protein levels, suggesting the presence of a hypoxic environment in these tumors. We also found a significant reduction in CAT activity levels in soft and hard mucin compared with healthy tissue samples. Discussion: In conclusion, our study provides the first evidence of low intratumoral oxygen levels in PMP patients associated with hypoxia and oxidative stress markers. However, further investigation is required to understand the potential role of oxidative stress in PMP in order to find new therapeutic strategies.

Antitumor effect of a small-molecule inhibitor of KRASG12D in xenograft models of mucinous appendicular neoplasms.

Pseudomyxoma peritonei (PMP) is a rare disease characterized by a massive accumulation of mucus in the peritoneal cavity. The only effective treatment is aggressive surgery, aimed at removing all visible tumors. However, a high percentage of patients relapse, with subsequent progression and death. Recently, there has been an increase in therapies that target mutated oncogenic proteins. In this sense, KRAS has been reported to be highly mutated in PMP, with KRASG12D being the most common subtype. Here, we tested the efficacy of a small-molecule KRASG12D inhibitor, MRTX1133, in a high-grade PMP xenograft mouse model carrying a KRASG12D mutation. The results obtained in this work showed a profound inhibition of tumor growth, which was associated with a reduction in cell proliferation, an increase in apoptosis, and a reduction in the MAPK and PI3K/AKT/mTOR signaling pathways. In conclusion, these results demonstrate the high potency and efficacy of MRTX1133 in KRASG12D-PMP tumors and provide a rationale for clinical trials.