The targeted SMAC mimetic SW IV-134 augments platinum-based chemotherapy in pre-clinical models of ovarian cancer

Background

Ovarian cancer is initially responsive to frontline chemotherapy. Unfortunately, it often recurs and becomes resistant to available therapies and the survival rate for advanced and recurrent ovarian cancer is unacceptably low. We thus hypothesized that it would be possible to achieve more durable treatment responses by combining cisplatin chemotherapy with SW IV-134, a cancer-targeted peptide mimetic and inducer of cell death. SW IV-134 is a recently developed small molecule conjugate linking a sigma-2 ligand with a peptide analog (mimetic) of the intrinsic death pathway activator SMAC (second-mitochondria activator of caspases). The sigma-2 receptor is overexpressed in ovarian cancer and the sigma-2 ligand portion of the conjugate facilitates cancer selectivity. The effector portion of the conjugate is expected to synergize with cisplatin chemotherapy and the cancer selectivity is expected to reduce putative off-target toxicities.

Methods

Ovarian cancer cell lines were treated with cisplatin alone, SW IV-134 alone and a combination of the two drugs. Treatment efficacy was determined using luminescent cell viability assays. Caspase-3/7, − 8 and − 9 activities were measured as complementary indicators of death pathway activation. Syngeneic mouse models and patient-derived xenograft (PDX) models of human ovarian cancer were studied for response to SW IV-134 and cisplatin monotherapy as well as combination therapy. Efficacy of the therapy was measured by tumor growth rate and survival as the primary readouts. Potential drug related toxicities were assessed at necropsy.

Results

The combination treatment was consistently superior in multiple cell lines when compared to the single agents in vitro. The expected mechanism of tumor cell death, such as caspase activation, was confirmed using luminescent and flow cytometry-based assay systems. Combination therapy proved to be superior in both syngeneic and PDX-based murine models of ovarian cancer. Most notably, combination therapy resulted in a complete resolution of established tumors in all study animals in a patient-derived xenograft model of ovarian cancer.

Conclusions

The addition of SW IV-134 in combination with cisplatin chemotherapy represents a promising treatment option that warrants further pre-clinical development and evaluation as a therapy for women with advanced ovarian cancer.

Abstract 110: Colon Cancer in Patients under 50 in Guatemala: A Retrospective Comparative Cohort Study

Purpose: Describing and comparing clinico-pathological characteristics of younger (<50 years) versus older (≥50 years) colon cancer patients treated at the Guatemalan Liga Nacional Contra el Cáncer e Institute of Cancer (Liga-INCAN).

Methods: This IRB-approved single-institution retrospective cohort study reviewed the medical and pathological records of patients ≥18 years diagnosed with colon cancer at the Liga-INCAN, the largest specialized oncologic hospital in Guatemala, from 2013-2019. Continuous data are presented as mean and standard deviation, categorical data as frequency and percentage. Subjects were categorized into two groups, younger group (<50 years) and older group (≥50 years). Statistical analyses were performed with Chi-squared, Fisher's exact test, and Kruskal-Wallis test.

Results: Among 123 patients, 34.74% were <50 and 65.26% ≥50 years. Most of patients in the younger group were male 68.83% in comparison to the older group where most were female (p<0.01), patients resided in the rural area 60.47% vs 50.0% respectively (p=0.18). BMI index in younger patients was below 25 in 56.1% vs 50.64% (p=0.30). Patients <50 years old were diagnosed at earlier stages (I and II) 39.54% vs 22.5% when compared with ≥50 years old patients (p<0.05), tumors were more common in the left compared to the right colon in younger patients (58.14% vs 50.0%), the difference was not significant (p=0.15). Histopathological features did not show significant differences, most tumors were adenocarcinomas for both groups, but signet ring cell carcinomas were more frequent in the younger than in older patients (9.30% vs 1.25%).

Conclusion: Our findings indicate that Guatemalan patients diagnosed with colon cancer younger than fifty years old are more frequently male and are diagnosed at earlier stages compared to older patients. Although, histopathological characteristics did not show significant differences, further studies are needed to understand how these impact the prognosis of the patients in the different age groups.

Funding: None

Citation Format: Angel Velarde, Alba Kihn-Alarcón, Hiram Gay, Jeff Michalski, Edgar Ruiz, Hugo Geoffrey, Vicky de Falla, Javier Figueroa, Kirk Douglas Najera, Carlos García, Kevin Ma, Ana Salazar, Abigail Zamorano, Sonia Dávila, Jacaranda van Rheenen. Colon Cancer in Patients under 50 in Guatemala: A Retrospective Comparative Cohort Study [abstract]. In: Proceedings of the 9th Annual Symposium on Global Cancer Research; Global Cancer Research and Control: Looking Back and Charting a Path Forward; 2021 Mar 10-11. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2021;30(7 Suppl):Abstract nr 110.

First Report of Cherry green ring mottle virus and Cherry necrotic rusty mottle virus in Sweet Cherry (Prunus avium) in Chile and South America

Cherry green ring mottle virus (CGRMV) infects several Prunus species, while Cherry necrotic rusty mottle virus (CNRMV) has been detected mainly in sweet cherry. In Chile, sweet cherry represents one of the most valuable fruit crops, and the country is the main producer of cherries in the southern hemisphere. In October 2011, leaf samples were collected from 21 trees of cv. Bing in Libertador General Bernardo O'Higgins and Maule regions. Leaves of symptomatic plants showed brown angular necrotic spots, the center of which can drop out giving a shot-hole appearance. Total RNA was extracted by the silica capture method (1). Reverse transcription (RT)-PCR was carried out to test the presence of CGRMV and CNRMV using primer pairs GRM7950/GRM8316 (1), and DetCNR-F (TCCCACCTCAAGTCCTAGCAGAGA) / DetCNR-R (TCATTGCTAATTGCAAAATCCCA). Ten and six samples were tested positive for CGRMV and CNRMV, obtaining 366- and 333-bp fragments, respectively. Mixed infections occurred in five samples. Two sets of primer pairs were designed to amplify a region of the genome which includes the entire coat protein (CP) gene: CGRM-CPF (GGCTGATGAAGAATTTGA-GAAG) and CGRM-CPR (GAGTGGAATTGCAGGGGTTT), and CNRM-CPF (GAGTGTGTGTGAGCTTTCAAGTT) and CNRM-CPR (TTCGCCCCGTGTTGTAAAAC). Amplicons of the expected size of 828 bp (CGRMV) and 892 bp (CNRMV) were obtained from infected samples. Three amplicons for each virus were cloned into pGEM-T and three colonies per cloned fragment were sequenced in both directions. For CNRMV, Chilean isolates CP9754 (GenBank Accession No. KC432619) and CP9956N (KC432621) had 98% for nucleotide identity with isolate JK10 from India (FN546178), while isolate CP9879 (KC432620) had 97% of nucleotide identity. For CGRMV, Chilean isolate CP3359 (KC432616) had 98% identity with isolate HI17 from Poland (JX468873), while isolates CP9731 (KC432617) and CP9956G (KC432618) had 98% and 99% nucleotide identity with isolate ita7 (AF533161) from Italy, respectively. Nucleotide and amino acid sequence identity between Chilean isolates of CGRMV ranged between 94.5% and 99.3%, and from 97.8% to 99.2%, respectively. For Chilean isolates of CNRMV, sequence identity ranged between 98.0% and 98.5% (nucleotide), and from 98.6% to 98.9% (amino acid). Sequence analysis indicated that CGRMV isolates found in Chile belong to group II (3). Detection was confirmed by non-isotopic molecular hybridization. Riboprobes were designed on the basis of a consensus sequence of CP gene and labeled with digoxigenin (2); are complementary to the fragments located from the nucleotide 7415 to 7576 for CGRMV (reference sequence NC 001946.1), and 7475 to 7638 for CNRMV (reference sequence NC 002468.1). The cultivar Bing manifested symptoms only when infected by CNRMV. Results suggest that CNRMV is the cause of symptoms and yield loss observed in Bing, the most important cherry variety cultivated in Chile. To our knowledge, this is the first report of CGRMV and CNRMV infecting sweet cherry in South America. References: (1) M. E. Rott and W. Jelkmann. Eur. J. Plant Pathol. 107:411, 2001. (2) J. A Sánchez-Navarro et al. Plant Pathol. 47:780, 1998. (3) Y. P. Zhang et al. J. Plant. Pathol. 82:49, 2000.

Systematic approach for severe respiratory failure due to novel A (H1N1) influenza

AIM

In April 2009, a novel influenza A (H1N1) virus appeared in Mexico. It rapidly acquired the characteristics of a pandemic disease. Our objective is to present a case series of mechanically ventilated patients with severe influenza, treated with a systematic approach.

METHODS

Prospective, observational, single-center study in a University Hospital. A (H1N1) virus was confirmed by rRT-PCR. In this report, we only considered patients that required mechanical ventilation (MV). All patients received antibiotics, steroids and oseltamivir from the time of admission. The main strategies incorporated in the systematic approach were a lung-protective strategy, PEEP adjusted for each patient, protocol-guided sedoanalgesia, restrictive fluid management, weaning protocol, and prolonged prone ventilation and extracorporeal membrane oxygenation (ECMO) as rescue therapies.

RESULTS

We studied 19 patients: age 41 ± 13 years old, APACHE II 16 ± 7 and SOFA 8 ± 4. All patients presented PaO2/FiO2 ≤ 200 before connection to MV. Their worst values within the first 24 hours for oxygenation index, PaO2/FiO2, and PaCO2 on MV were 21.8 ± 13, 98 ± 39, and 48 ± 16 mmHg, respectively. Sixteen patients achieved ARDS; three exhibited acute lung injury criteria. Ten required a prone position, and two required ECMO (one patient required both therapies). Time on MV was 16 ± 13 days. Length of stay in the ICU and in hospital was 18 ± 12 and 28 ± 17 days, respectively. Mortality was 21%.

CONCLUSION

Severe hypoxemia and a high rate of rescue therapies were observed among our patients. Nevertheless, mortality was lower than previously reported in comparable populations, which may be related to the management by a critical care team and the use of a systematic approach for ventilatory and non-ventilatory therapeutic strategies.

Phytoplasmas Associated with Grapevine Yellows Disease in Chile

An extensive survey was performed from 2002 to 2006 to detect and identify phytoplasmas associated with Chilean grapevines. Nested polymerase chain reaction assays using phytoplasma universal primer pairs P1/P7 and R16F2n/R2 detected phytoplasmas in 34 out of the 94 samples tested (36%). Restriction fragment length polymorphism (RFLP) analyses, cloning, and sequencing allowed identification of phytoplasmas belonging to ribosomal subgroups 16SrI-B, 16SrI-C, 16SrVII-A, and 16SrXII-A. The 16SrVII-A phytoplasma represents a new finding in grapevine; moreover, variability of the RFLP profile was observed in some of the 16SrXII-A phytoplasmas, indicating possible new ribosomal subgroups. Mixed phytoplasma infections and infections of phytoplasmas together with one or more viruses also occurred.

Production of antimicrobial substances, by hospital bacteria, active against other micro-organisms

Fifty-nine clinical strains of bacteria, isolated from patients in the Regional Hospital of Talca, were studied. Seventy-four percent of these strains produced antibacterial substances, in comparison with 18% of the same bacterial species obtained from patients from a non-hospital habitat. Almost all the bacteria isolated from hospitalized patients demonstrated in vitro resistance to different antimicrobial agents. Pseudomonas aeruginosa was the most frequent species producing antibacterial substances and its products were of high potency, with a wide spectrum of antimicrobial activity. Cure of plasmid DNA, in most of the antibacterial-producer strains, resulted in the loss of their lethal activity and they also became susceptible in vitro to anti-microbials. These results indicated that such properties are encoded in extrachromosomal DNA. We believe that the knowledge of the antimicrobial activity and resistance to antimicrobials of bacteria from a hospital habitat can help explain the selection and persistence of such strains in this particular ecological niche.

Effects of exogenous neurotensin on intestinal postresectional growth in the suckling rat

BACKGROUND

In the suckling rat, massive bowel resection provokes intestinal malabsorption that leads to diminished growth. The object of this report was to test whether neurotensin, intestinal trophic peptide, enhances postresection intestinal adaptation, improving absorption and reducing the adverse effects of resection on growth.

METHODS

Fifty-seven 15-day-old suckling. Wistar rats were divided into four groups: 41 rats were subjected to resection of 90% of their small bowel, while the rest (n = 16) underwent laparotomy. Half of the animals, resected and laparotomized, were treated with neurotensin for 30 days. The body weight was monitored, and samples of bone and intestinal mucosa were obtained at the end of the study period for analysis. Blood was tested to determine iron, ferritin, folic acid, and vitamin B12 levels.

RESULTS

The resected animals lost body weight regardless of neurotensin administration. In the resected animals, femur weight increased significantly when they received neurotensin. Bowel resection provokes significant increases in the intestinal mucosa (crypts and villi), but after neurotensin administration, significant increases were detected only in the jejunum of the resected animals but not in the ileum of laparotomized rats. In the resected animals, significant decreases in iron, ferritin, folic acid, and vitamin B12 levels were observed. The postresection administration of neurotensin only produced a significant rise in the ferritin concentration.

CONCLUSIONS

In the suckling rat, neurotensin enhances the intestinal proliferative phenomenon but does not improve the course of medium-term postresection growth.

[The treatment of anemia in patients on hemodialysis with recombinant human erythropoietin]

BACKGROUND

Anaemia of chronic renal failure is primarily due to relative erythropoietin deficiency. This hormone has been recently cloned and it is now available for clinical use.

METHODS

Sixteen patients maintained on haemodialysis with non-complicated anaemia and on stable clinical condition were selected for 12 months' treatment with r-HuEPO. Our aim was to analyse the factors influencing r-HuEPO response and the modifications on main haematological and biochemical parameters and adverse reactions occurrence.

RESULTS

All patients responded with an increase of haemoglobin (from 78 +/- 9 to 103 +/- 18 g/dl at second month of therapy, p less than 0.001) and blood transfusions were eliminated. Time of response and doses were very different to one another. R-HuEPO requirements decreased slowly with time. Neither transfusion number, nor hyperparathyroidism, nor ferritin levels, nor diabetic condition influenced r-HuEPO response. Serum ferritin decreased significantly from 1,772 +/- 1,791 to 1,116 +/- 1,240 ng/ml (p less than 0.05), especially in patients without iron overload. Serum vitamin B12 levels did not decrease significantly. Both uric acid and phosporus increased significantly after the treatment period (5.25 +/- 1.18 to 6.29 +/- 0.99 mg/dl and 5.78 +/- 1.29 to 6.69 +/- 1.55 mg/dl respectively, p less than 0.01). Platelet counts did not modify. It was necessary to adjust antihypertensive therapy in a few patients because of a mild rise in blood pressure, although important adverse reactions did not occur.

CONCLUSIONS

Anaemia of haemodialysis patients improves with r-HuEPO treatment and reduces blood transfusion requirement. Adverse effects are not very remarkable.