Prevalence, geographic distribution and phenotypic differences of Piscirickettsia salmonis EM-90-like isolates

Early reports accounted for two main genotypes of Piscirickettsia salmonis, a fish pathogen and causative agent of piscirickettsiosis, placing the single isolate EM-90 apart from the prototypic LF-89 and related isolates. In this study, we provide evidence that, contrary to what has been supposed, the EM-90-like isolates are highly prevalent and disseminated across Chilean marine farms. Molecular analysis of 507 P. salmonis field isolates derived from main rearing areas, diverse hosts and collected over 6 years, revealed that nearly 50% of the entire collection were indeed typed as EM-90-like. Interestingly, these isolates showed a marked host preference, being recovered exclusively from Atlantic salmon (Salmo salar) samples. Although both strains produce undistinguishable pathological outcomes, differences regarding growth kinetics and susceptibility to the antibiotics and bactericidal action of serum could be identified. In sum, our results allow to conclude that the EM-90-like isolates represent an epidemiologically relevant group in the current situation of piscirickettsiosis. Based on the consistency between genotype and phenotype exhibited by this strain, we point out the need for genotypic studies that may be as important for the Chilean salmon industry as the continuous surveillance of antimicrobial susceptibility patterns.

Prevalence, geographic distribution and phenotypic differences of Piscirickettsia salmonis EM-90-like isolates

Early reports accounted for two main genotypes of Piscirickettsia salmonis, a fish pathogen and causative agent of piscirickettsiosis, placing the single isolate EM-90 apart from the prototypic LF-89 and related isolates. In this study, we provide evidence that, contrary to what has been supposed, the EM-90-like isolates are highly prevalent and disseminated across Chilean marine farms. Molecular analysis of 507 P. salmonis field isolates derived from main rearing areas, diverse hosts and collected over 6 years, revealed that nearly 50% of the entire collection were indeed typed as EM-90-like. Interestingly, these isolates showed a marked host preference, being recovered exclusively from Atlantic salmon (Salmo salar) samples. Although both strains produce undistinguishable pathological outcomes, differences regarding growth kinetics and susceptibility to the antibiotics and bactericidal action of serum could be identified. In sum, our results allow to conclude that the EM-90-like isolates represent an epidemiologically relevant group in the current situation of piscirickettsiosis. Based on the consistency between genotype and phenotype exhibited by this strain, we point out the need for genotypic studies that may be as important for the Chilean salmon industry as the continuous surveillance of antimicrobial susceptibility patterns.

A controlled trial of pravastatin vs probucol in the treatment of primary hypercholesterolemia

We compared the safety, tolerability and efficacy of the HMGCoA reductase inhibitor pravastatin and probucol in the treatment of patients with primary hypercholesterolemia using an active, drug controlled, double blind, randomized, double placebo design. Patients were included if LDL-C levels after a minimum of six weeks on an AHA phase I diet were greater than 150 mg/dL and triglycerides were less than 350 mg/dL. Included patients were randomly assigned to either pravastatin 40 mg pm or probucol 500 mg bi. They also received matching placebos for each drug. The active drug period lasted 16 weeks, during which the patients were seen at 4, 8, 12 and 16 weeks after baseline. There were no significant differences in baseline values between both treatment groups. Significantly lower values of total cholesterol and LDL-C were observed with pravastatin as compared to probucol. While a non significant increase of HDL-C was observed with pravastatin, a remarkable and statistically significant decrease was observed with probucol. A large dispersion of triglycerides levels was observed with both drugs and no statistically significant changes were demonstrated. Both pravastatin and probucol were well tolerated: only minimal clinical and laboratory changes, not considered to have been drug-related, were observed. No changes, considered drug-related, were observed in the cristalline lens. This study shows an overall superiority of pravastatin over probucol with significant larger decreases of total cholesterol and LDL-C and a better effect on HDL-C.

Cellular and molecular effects of PNCK, a non-canonical kinase target in renal cell carcinoma

Renal cell carcinoma (RCC) is a fatal disease when advanced. While immunotherapy and tyrosine kinase inhibitor-based combinations are associated with improved survival, the majority of patients eventually succumb to the disease. Through a comprehensive pan-cancer, pan-kinome analysis of the Cancer Genome Atlas (TCGA), pregnancy-upregulated non-ubiquitous calcium-calmodulin-dependent kinase (PNCK), was identified as the most differentially overexpressed kinase in RCC. PNCK overexpression correlated with tumor stage, grade and poor survival. PNCK overexpression in RCC cells was associated with increased CREB phosphorylation, increased cell proliferation, and cell cycle progression. PNCK down-regulation, conversely, was associated with the opposite, in addition to increased apoptosis. Pathway analyses in PNCK knockdown cells showed significant down-regulation of hypoxia and angiogenesis pathways, as well as the modulation of the cell cycle, DNA damage, and apoptosis pathways. These results demonstrate for the first time the biological role of PNCK, an understudied kinase, in RCC and validate PNCK as a druggable target.

Digital dynamic telepathology--the Virtual Microscope

The Virtual Microscope is being designed as an integrated computer hardware and software system that generates a highly realistic digital simulation of analog, mechanical light microscopy. We present our work over the past year in meeting the challenges in building such a system. The enhancements we made are discussed, as well as the planned future improvements. Performance results are provided showing the system scales well, so that many users can be adequately serviced by an appropriately configured data server.

[Epidermoid cyst of the testis. Report of 2 cases]

We report 2 patients with epidermoid cyst of the testis. Clinical, histological and echographic aspects are discussed. A radical orchyectomy was performed in one patient, a partial one in the other. A successful outcome followed in each case.

Follow-up of concomitant treatment with gemcitabine/radiotherapy in locally advanced squamous cell carcinoma of head and neck

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Background: The stages of the locally advanced head and neck cancer have a negative prognosis, therefore, new treatments are continuously explored. One of these treatments consists of the use of Gemcitabine concomitant with radiotherapy. We previously evaluated the rate of response and the toxicity profile of this treatment in 15 patients and now we are reporting the follow up of such study. Methods: Fifteen patients, with histological report of locally advanced squamous cell carcinoma of head and neck, initiated treatment of Gemcitabine at intravenously doses of 50 mg\m2 per application weekly concomitant with radiotherapy. The radiotherapy consisted of an initial photons dose of 3960 cGy in 22 fractions of 180 cGy to the primary site and regional lymph with posterior increments of 2880 cGy in 16 fractions of 180 cGy excluding the spinal cord and electrons increments if necessary. Results: In 9 of the 15 patients complete response was obtained, achieving organ preservation. Four of the 15 patients presented a partial response and two presented progression. The principal severe toxicity presented was mucositis. The mean follow-up is 23 months with a range of 19–27 months. From the 9 patients that presented a complete response, one presented bone recurrence 13 months after achieving the total response; another one of them died because an infectious process without evidence of tumoral activity. The rest 7 patients are to the present date without evidence of tumoral activity. One of the patients with partial response is still alive with tumoral activity in central nervous system. The remaining patients died due to tumoral activity. Conclusions: In our study with 15 patients an overall response of 87% was obtained. With a follow up to 23 months only one recurrence has been presented. We concluded that the treatment is feasible and it could have an impact in the overall survival but studies with a greater number of patients and a larger follow up are needed.

No significant financial relationships to disclose.

Abstract 95: In vitro, in vivo and molecular effects of triptolide and minnelide in renal cell carcinoma

Background: The worldwide incidence of Renal Cell Carcinoma (RCC) is increasing. Although new therapies have improved outcomes in advanced RCC, most patients eventually fail treatment and succumb to this devastating disease. Systemic therapy strategies have focused on TKI and immunotherapy, alone or in combination. Triptolide, a diterpenoid epoxide extracted from Tripterygium wilfordii Hook f (TWHf), has potent antitumor activity in multiple cancer models. Few studies have focused on the potential of triptolide as a novel therapeutic option in RCC.

Objective: the objectives of this study are to characterize the in vitro and in vivo effects of Triptolide (T) and its water-soluble form, Minnelide (M), in models of renal cell carcinoma.

Methods: The in vitro effects of triptolide (T) on human and murine RCC (786-0, A498, Caki-1, ACHN, and RENCA) cell proliferation was assessed using cell count and xCelligence assays at 24, 48, 72 and 96h. Molecular and mechanistic characterization of triptolide’s effects in 786-0 cells were analyzed by the (Reverse Phase Protein Array) and validated by western blot analysis. The in vivo effects (tumor progression and survival) of M were assessed in nude mice bearing 786-0 tumors (8x106 cells per mouse). M was administered to tumor-bearing mice at two different doses (0.21mg/kg and 0.42mg/kg daily), intraperitoneally, for 21 days. Correlative studies to explain the in vivo effect of M and the correlation with the molecular changes in vitro seen are being performed and will be shown in the poster.

Results: T significantly inhibited, in a dose-response manner, cell proliferation in all human and murine renal cancer cell lines, with IC50 ranging between 12.5 and 25 nM). T was associated with significant negative modulation of proliferation, cell cycle, survival, increased apoptosis, and ER stress pathways in 786-0 cells, as demonstrated by RPPA analysis and validated by western Blot of selected pathway proteins, such as apoptosis (PARP cleavage and Caspase 3 activation), ER stress induction (pEIF2a, CHOP), and down-regulation of survival and proliferation pathways (pAKT). In vivo, M was associated with significant antitumor effects in 786-0 xenografts, with complete responses in the majority of mice while on treatment. These effects were associated with significant prolongation in overall survival in M treated vs. control mice. No significant toxicity or treatment-related deaths were observed.

Conclusion: Our results have shown for the first time the potent in vitro and in vivo antitumor effects of T in RCC and the molecular changes associated with these effects. The profound antitumor effects in the aggressive 786-0 RCC xenograft model are highly encouraging and warrant further preclinical studies and potential clinical trials of M this devastating disease. Correlative tumor studies to understand the mechanisms of M in vivo antitumor effects are underway and will be presented at the meeting.

Citation Format: Valery A. Chavez, Floritza Bustamante, Abner Murray, Ashok Saluja, Jaime Merchan. In vitro, in vivo and molecular effects of triptolide and minnelide in renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 95.

Abstract 6793: In vivo effects and molecular mechanisms of Minnelide mediated enhancement of measles virus oncolysis in human colorectal cancer

Background: The development of novel biotherapies for metastatic colorectal cancer (CRC), a fatal disease when advanced, is an urgent medical need. Oncolytic viruses (OVs) are novel cancer biotherapies, and the oncolytic measles virus (MV) has demonstrated safety and antitumor activity in early clinical studies. Triptolide (TRP), a diterpenoid epoxide extracted from the thunder god vine, and Minnelide (MN), its water-soluble compound, are novel agents associated with potent antitumor, anti-proliferative, pro-apoptotic, antiangiogenic, and ER stress inducing effects. The objectives of this study are to characterize the in vitro and in vivo effects and molecular mechanisms of measles virotherapy in combination with TRP and MN in CRC.

Methods: The in vitro effects of TRP, MV-GFP (Edmonston strain of Measles virus expressing eGFP), MV-CD46-muPA (dual targeted MV against the murine uPA receptor and human CD46), or virus-triptolide combinations on tumor cell cytotoxicity were assessed on HT-29, HCT116 and SW620 CRC cells. Molecular and mechanistic characterization of TRP’s effects alone and combination with MV in HT29 cells was analyzed by the Reverse Phase Protein Array (RPPA) and validated by western blot analysis. In vivo effects (tumor progression and survival) of MN alone and in combination with MV vectors using different treatment schemes were assessed in HT-29 tumor bearing NSG mice, and tumor correlative studies were performed.

Results: MV and TRP had single agent antitumor activity against human CRC cell lines. MV-TRP combinations were associated with increased in vitro cytotoxicity compared to single agent treatments. Functional proteomics analysis showed that TRP-MV combinations were associated with inhibition of survival and proliferation pathways, such as AKT, ERK, inhibition of HSP70 as well as induction of autophagy, at a higher level than each agent alone. In vivo, both a 7-days MN treatment and a 21-days MN treatment significantly improved long term tumor control and significantly improved survival, compared to each agent alone. Tumor studies showed that MN increased MV tumor deposition, as well as enhancement in apoptosis and inhibition of proliferation. Molecular characterization of oncogenic pathways modulated by MV-Minnelide combinations (Nanostring) are underway and will be presented at the meeting.

Conclusions: Our results demonstrated that, in human CRC xenografts, Minnelide safely and significantly enhances measles virus oncolysis in vivo, leading to improved antitumor effects and prolonged survival. These effects were associated with enhanced antiproliferative and pro-apoptotic effects with the MV-Minnelide combination, suggesting in vivo synergy. Studies characterizing the molecular mechanisms of in vivo synergy and assessing this promising combination in immunocompetent CRC models are underway.

Citation Format: Valery A. Chavez, Floritza Bustamante, Carolina Merchan-Mendes, Ashok Saluja, Jaime Merchan. In vivo effects and molecular mechanisms of Minnelide mediated enhancement of measles virus oncolysis in human colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6793.