Immunotherapy in Acute Leukemias: Past Success Paves the Way for Future Progress

Immunotherapy as a cancer treatment modality has undergone recent widespread proliferation across all cancer types, especially amongst patients with solid tumors. However, the longest tenured immunotherapy approach to cancer is allogeneic stem cell transplantation (allo-SCT) for two hematologic malignancies: acute myeloid and acute lymphoid leukemia (AML and ALL, respectively). While allo-SCT remains a standard of care for eligible patients, recent advances/applications of monoclonal antibodies, immune checkpoint inhibitors, bispecific T-cell engagers (BiTEs), and CAR T-cell therapy are changing the treatment landscape for these acute leukemias by either direct to tumor immune targeting or through decreased toxicities that expand patient eligibility. Pre-clinical data and clinical trials have shown promising results for novel immunotherapies in acute leukemia, and multiple ongoing trials are investigating these novel approaches. While there have been promising results with these approaches, particularly in the relapsed/refractory setting, there remain challenges in optimizing the use of these therapies, such as managing cytokine release syndrome and other immune-related toxicities. Immunotherapy is a rapidly evolving field in the treatment of acute leukemia and has the potential to significantly impact the management of both AML and ALL. This review highlights the history of immunotherapy in the treatment of acute leukemias, the evolution of immunotherapy into more targeted approaches, the potential benefits and limitations of different immune targeting approaches, and ongoing research and development in the field.

Survival analysis of patients with early and standard onset colorectal cancer: A single center study

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Background: While more aggressive clinical/pathological features have been consistently described in between patients with early-onset (EO) and standard-onset (SO) colorectal cancer (CRC), survival data have been conflicting. While some studies report better survival rates for EO-CRC; others found that outcomes among groups are not different. In a prior study, using the Surveillance, Epidemiology and End Results (SEER), we reported that cancer-related survival did not differ between EO-CRC and SO-CRC; however, a main limitation was the lack of molecular status and treatment details among groups. This study aims to compare the survival of EO-CRC and SO-CRC patients at Montefiore Medical Center. Methods: Retrospective cohort among 690 patients diagnosed with metastatic colorectal cancer (CRC) at Montefiore Medical Center between 2010 and 2018. Patients were identified using the software Clinical Looking Glass and charts were reviewed manually to gather information about demographics (race/ethnicity defined as Non-Hispanic White [NHW], Non-Hispanic Black [NHB] and Hispanic [H], gender, comorbidity index, calculated using the Charlson comorbidity score), clinicopathological features (grade, tumor sidedness, K-ras mutation) and treatment-related characteristics (metastatectomy, lines of chemotherapy and use of biologics). EO-CRC was defined as CRC diagnosis before age 50 and SO-CRC as CRC diagnosed at 50 years or older. Overall survival was compared between EO-CRC and SO-CRC using Kaplan Meier and Cox regression analyses. Stata v15.1 was used for statistical analysis. Results: Of 690 patients with CRC, 139 (20.1%) had EO-CRC and 551 (79.9%) had SO-CRC. Participants with EO-CRC had a higher frequency of poorly-differentiated tumors (35.5% vs. 23.8%, p = 0.02), a lower comorbidity index (6 vs. 7, p < 0.001). and a higher use of biologics (70.5% vs. 60.8%, p = 0.03) compared to SO-CRC. K-ras mutation was available for 377 (54.5%) of cases and did not differ among groups (45.9% vs. 45.9%, p = 0.99). In a model adjusted for race/ethnicity, gender, comorbidity index, sidedness, use of biologics and metastatectomy, there was no difference in mortality among groups (HR:0.9, 95%CI: 0.58 – 1.43, p = 0.68). This result remained unchanged in a model restricted to patients with available K-ras-status (n = 75), adjusted for all these variables. Conclusions: Despite more aggressive clinical/pathological features in patients with EO-CRC, survival does not differ compared to SO-CRC.

Factors associated with long-term survival in patients with early-onset and standard-onset colorectal cancer

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Background: Differences in incidence, clinical features, and survival between early-onset (EO) and standard-onset (SO) colorectal cancer (CRC) are well-established. Factors associated with longer survival have not been reported. We aim to determine clinical and treatment factors associated with longer survival in patients (pts) with metastatic EO and SO CRC. Methods: Pts with metastatic CRC diagnosed between 2010-2019 at two NYC hospitals were identified by tumor registry and classified as EO (diagnosis at < 50 years) or SO (diagnosis at ≥ 50 years). Median overall survival (OS) was calculated for each group using Kaplan Meier curves. Long-term survival was defined as OS > 2 years (EO-CTC median OS). Data was collected by chart review and compared between short vs long-term survivors in EO and SO CRC pts independently. Stata v15 was used for statistical analysis. Results: Of 646 pts, 144 (22.3%) had EO and 502 (77.7%) had SO. High grade tumors were more likely in EO (33.3% vs 24%, OR: 1.59, p = 0.04) than SO; whereas no differences were seen in gender, sidedness, KRAS mutation or chemotherapy. Biologics were used more frequently in EO than SO (OR = 1.7; p = 0.008]. Median OS was 2.1 and 1.9 years in EO and SO. There were 53 (36.8%) and 175 (35.1%) long-term survivors in EO and SO groups. In pts with SO, metastasectomy, irinotecan-based chemotherapy and use of biologics were significantly associated with long-term survival, whereas metastasectomy was the only associated factor in pts with EO. Conclusions: Metastatectomy was the only factor associated with longer survival in both EO and SO groups. Other clinical/pathological and treatment-related factors associated with long-term survival among SO-CRC were not associated with long-term survival among EO-CRC patients. [Table: see text]

Racial ethnic disparities in clinical/pathological features, treatment, and survival among patients with early-onset colorectal cancer

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Background: Globally, the incidence of early-onset colorectal cancer has risen. Racial disparities in colorectal cancer (CRC) are well-described, however data in EO by race/ethnicity is lacking. We aim to compare the presenting features, treatment, and survival features of patients with metastatic early-onset CRC (EO). Methods: Patients with metastatic CRC diagnosed between 2010-2019 at two NYC hospitals were identified by tumor registry (n = 646). Clinical/pathological features, treatment and survival data was collected by chart review and compared between Non-Hispanic Whites (NHW), Non-Hispanic Blacks (NHB) and Hispanics (H) using Chi-square or Fisher’s exact test. Kaplan Meier curves were plotted to compare overall survival (OS) among groups. Stata v15 was used for statistical analysis. Results: Of 646 CRC patients, 126 (21.5%) were NHW, NHB or H diagnosed with EO with a frequency ranging from 16.6% in NHW to 26.1% in H. Non statistically significant lower frequencies of male gender, low/moderate grade, left-sided tumors,and higher frequency of KRAS mutations were seen in NHB (Table). Metastectomy was performed in 20 patients (13.9%) and did not differ between groups. There was no difference in the use of chemotherapy or biologics in general (Table), but NHW were more likely to get cetuximab than NHB (OR:4.5, p = 0.02) and H (OR:4.7, p = 0.02).There were no differences in median OS (1.8 vs. 2.2 vs. 2 years, p = 0.9)or 1-year OS (72% vs 72.3% vs 70.8%) in NHW, NHB and H, respectively. A lower 5-year OS was seen in NBH (14.5%) and Hispanics (24.4%) compared to NHW (44%). Conclusions: EO-CRC is more frequently seen in minority racial/ethnic groups. Despite no differences in the use of chemotherapy or biologic treatment in general, NHB have a lower 5-year survival rate compared to NHW and H. [Table: see text]

Splenic Laceration: A Rare Complication of Abdominal Paracentesis

Abdominal paracentesis is a commonly performed diagnostic and therapeutic procedure with a low complication rate. Previously described complications include injury to the abdominal wall, small bowel perforation, and abdominal hemorrhage. Splenic injury has also been described as a complication from bedside procedures including colonoscopy, upper gastrointestinal endoscopy, thoracentesis, and pleural biopsy. This case highlights a previously unreported complication from an abdominal paracentesis, splenic laceration.

Clinical characteristics and outcomes of patients with advanced hepatocellular carcinoma treated with immunotherapy: A “real world” retrospective study

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Background: Advanced hepatocellular carcinoma (HCC) is an aggressive malignancy with dismal prognosis. Newer agents, including immunotherapy (IO), have been granted accelerated approval for patients previously treated or unable to tolerate sorafenib. However, information outside clinical trials is scarce. This study aims to describe clinical characteristics and outcomes of HCC patients treated with IO. Methods: HCC patients treated with IO were identified using the institutional software, Clinical Looking Glass. Data regarding demographics, clinical and treatment characteristics were collected by chart review. Neutrophil/lymphocyte ratio (NLR) and AFP were collected at IO treatment initiation and considered low if below 4 and 400, respectively. Progression-free survival (PFS) was defined as time from treatment initiation to progression of disease or death, and overall-survival (OS) as time from IO initiation to death from any cause. Disease characteristics were analyzed using descriptive statistics, PFS and OS were plotted using Kaplan-Meier curves. Results: 52 patients with a median age of 64.5 years and male predominance (38, 73.1%) were identified. There were 24 (54.5%) Hispanics, 9 (20.5%) Non-Hispanic Blacks, 7 (15.9%) Non-Hispanic White and 4 (9.1%) Asians. Cirrhosis present in 41 (83.7%), median MELD of 8 (IQ: 7-10). 37 (77.1%) patients had ECOG 0-1. Hepatitis B and C and B infection were encountered in 12 (24.5%) and 22 (44%) patients, respectively. Intravascular invasion present in 16 (34.8%) and extrahepatic metastases in 7 (14.9%). Local treatment was provided to 29 (59.2%) and radiation to 14 (28.6%). First line treatment (tx1) was Sorafenib in 29 (55.8%) and Nivolumab in 21 (40.4%). Nivolumab was second line treatment or beyond (tx2) in 31 (59.6%). Median PFS was 6.2 (3.1-10.6) months and it did not differ between tx1 and tx2 (8 vs 5.9 months, p = 0.90). Median OS was 13.2 months; there was a tendency towards higher survival rates in patients that were treated in tx2 (11.8 vs 14.3 months, 0 = 0.59) and in patients with low NLR (14.8 vs 9.2 months, p = 0.14). Median OS was higher in patients with low AFP at IO treatment initiation (15.7 vs. 9.2 months, p = 0.03). Conclusions: In this multiethnic cohort, the “real world” experience of the benefit of IO in HCC is encouraging, with a median OS exceeding one year. NLR showed potential as a possible biomarker. Expanded data may elucidate the differences if any, between use of IO as front vs. second line therapy, in PFS and OS.

The impact of biologic agents in patients with metastatic colorectal cancer by race/ethnicity

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Background: Biologic agents have shown to improve overall survival (OS) in patients with metastatic colorectal cancer (mCRC). However, minority racial/ethnic groups were underrepresented in clinical trials. A retrospective study in a racially-diverse population diagnosed between 2000 - 2011, done by our group, reported a survival benefit with biologics; but, a subgroup analysis suggested that it was restricted to Non-Hispanic whites (NHW) only. This study aims to compare OS in patients with mCRC treated with chemotherapy and biologic agents (CBT) among racial/ethnic groups. Methods: Patients diagnosed with mCRC between 2012-2018 and treated with CBT at 3 cancer centers in the Bronx, NY were identified. Clinical data was collected by retrospective review for demographics (age at metastasis, gender and race/ethnicity categorized as Non-hispanic Black (NHB), NHW or Hispanic), pathological/ treatment characteristics (tumor grade, primary location, chemotherapy regimen, biologic agent). Cases without available race/ethnicity were excluded. OS was measured as time from mCRC diagnosis to death (verified from the National Death Index) and was compared among racial/ethnic groups using Kaplan-Meier curves. Results: A total of 278 patients; of whom 84 (42.4%) were Hispanic, 70 (35.4%) NHB and 44 (22.2%) NHW were included. The median age at diagnosis was 60 years and did not differ among racial/ethnic groups (62.5 vs 55.5 vs 56 years, p=0.07). There was a female predominance in NHB and Hispanics. Bevacizumab was more frequently used in Hispanics and NHB compared to NHW (95.2% vs. 92.9% vs. 77.3%, p=0.003, respectively). There were no differences in the frequency of cetuximab and panitumumab use. Median OS did not differ by racial/ethnic groups (21 in NHW vs. 22.8 in Hispanics and 28.6 months in NHB, p=0.40). Conclusions: Minority groups attain a similar survival benefit from the addition of biologics compared to NHW. Population-based studies are required to confirm these results.

Clinical characteristics and outcomes of patients with advanced hepatocellular carcinoma treated with immunotherapy: A real-world retrospective study

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Background: Advanced HCC is an aggressive malignancy with dismal prognosis. Newer agents, including immunotherapy (IT), have been granted accelerated approval. Information outside clinical trials is scarce. This study is aimed to describe the clinical characteristics and outcomes of HCC patients treated with IT. Methods: Patients with HCC treated with IT were identified using the institutional data-mining software, Clinical Looking Glass. Patient demographics, clinical, and treatment characteristics were collected. Progression-free survival (PFS) was defined as time from treatment initiation to disease progression or death, and overall-survival (OS) as time from diagnosis of advanced disease to death. PFS and OS were plotted using Kaplan-Meier curves. Results: A total of 52 patients; median age 64 years; male predominance (38, 73.1%) were identified. There were 24 (54.5%) Hispanics, 9 (20.5%) Non-Hispanic Blacks, 7 (15.9%) Non-Hispanic White and 4 (9.1%) Asians. Cirrhosis was seen in 41 (83.7%), and median MELD score was 8 (IQ: 7-10). Hepatitis B and C infection were encountered in 12 (24.5%) and 22 (44%) patients, respectively. Imaging evidence of intravascular invasion was seen in 16 (34.8%) and extrahepatic metastases in 7 (14.9%) cases. Local treatment was provided to 29 (59.2%) and radiation treatment to 14 (28.6%) patients. Nivolumab was used in all the cases, as first-line treatment in 17 (32.7%) and as ≥ second line in 35(67.3%). The median PFS was 6.2 (3.1-10.6) months and was similar in first-line and ≥ second line treatment (8 vs 5.9 months, p=0.90). The median OS was 24.2 (18-28) months; there was a tendency towards higher survival rates in patients that were treated in ≥ second line (16.8 vs 25.2 months, 0=0.07). Conclusions: In this multiethnic cohort, the “real world” experience of the benefit of IT in HCC is encouraging, with a median OS exceeding two years. Expanded data may elucidate the differences if any, between use of IT as front vs. second line therapy, in PFS and OS.

Differential Efficacy of Anti-VEGF Antibodies Based on Sex and Race in a Diverse Cohort of Advanced Nonsquamous Non-Small Cell Lung Cancer

OBJECTIVES

Bevacizumab with chemotherapy improved overall survival (OS) in the E4599 trial in metastatic nonsquamous non-small cell lung cancer (NS-NSCLC). A meta-analysis demonstrated an OS benefit with bevacizumab only in a subset of nonwhite patients. We explored the efficacy of antivascular endothelial growth factor antibodies (AVA) in a diverse cohort.

MATERIALS AND METHODS

Patients with advanced (stage IIIB/IV, American Joint Committee Cancer 7th edition) recurrent or metastatic NS-NSCLC diagnosed January 2006 to December 2017 at a single medical center were included. Survival analysis was performed with log-rank testing of the Kaplan-Meier estimator. Univariate models were constructed, and significant variables, age, sex, race were incorporated into a multivariate Cox proportional hazard model. Data analysis was performed on SAS.

RESULTS

A total of 171 patients, 80 were treated with AVA and 91 were untreated. Median age: 63 years, 55% females, 19% non-Hispanic whites, 44% blacks and 32% Hispanic whites; median 40 pack-years of smoking; 11.7% had sensitizing epidermal growth factor receptor mutations. Patients who received AVA had a survival benefit (26.6 vs. 19 mo, P=0.025). Adjusting for age, sex, race/ethnicity, epidermal growth factor receptor mutations, Eastern Cooperative Oncology Group performance status and number of metastases; AVA therapy was associated with improved OS (adjusted hazard ratio=0.62; P=0.049). In a subgroup analysis, females had survival benefit with AVA (median survival: 29.1 vs. 14.2 mo, log-rank P=0.02) which was significant in the adjusted model (adjusted hazard ratio=0.52; P=0.049).

CONCLUSIONS

In a diverse cohort of patients with advanced NS-NSCLC, a survival benefit was confirmed with AVA. The greatest magnitude of benefit was in blacks and non-Hispanic whites. A significant survival benefit was limited to female patients.

Clinicopathologic predictors of worse outcome in early onset colorectal cancer (EO-CRC): A single-institution experience

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Background: A growing body of evidence indicates an increasing incidence of CRC diagnosis prior to age 50 years. Despite improvements in morbidity and mortality in metastatic CRC (mCRC), racial disparities persist. Limited data is available on the influence of clinical and pathologic factors on outcomes in EO-CRC. We aim to analyze variables which may serve as prognostic markers in a racially diverse, under-served EO-CRC population. Methods: All mCRC patients (n=321) diagnosed between 2004-12 were identified through the institutional tumor registry and charts were reviewed for age at diagnosis, gender, race, site of primary and metastatic tumors and histologic grade. Clinical outcome was measured in terms of overall survival (OS). Clinicopathologic characteristics were compared with a t test between EO and standard onset (SO) groups. Multivariate analyses were performed to assess influence on EO-CRC. Results: Of the 321 patients, 60 (18.7%) had EO-CRC, with median age at diagnosis 42 years. Both groups showed a female preponderance (Table), with colon being the prevalent primary site (~70%). On analysis of racial distribution, non-Hispanic whites (NHW) and non-Hispanic blacks (NHB) had a lower incidence of EO-CRC compared with Hispanic (H) and Asian (A) patients (12.7% v 17.6% v 26.7% v 40%, p= 0.07). Additionally, EO-CRC had a higher incidence of high-grade histology (42.6% v 25.8%, p=0.09), which on multivariate analysis had a significant influence on clinical outcome (p<0.01). Median OS in the EO group was 2.1 years compared to 2.7 years in the SO group. Conclusions: EO-CRC is an aggressive malignancy with distinct pattern of racial distribution. Histologic grade has the potential to serve as a negative prognostic marker. Further analysis of patients diagnosed between 2013-18 is underway. [Table: see text]

Identification of Natural Products That Inhibit the Catalytic Function of Human Tyrosyl-DNA Phosphodiesterase (TDP1)

Tyrosyl-DNA phosphodiesterase 1 (TDP1) is an enzyme crucial for cleavage of the covalent topoisomerase 1-DNA complex, an intermediate in DNA repair. TDP1 plays a role in reversing inhibition of topoisomerase I by camptothecins, a series of potent and effective inhibitors used in the treatment of colorectal, ovarian, and small-cell lung cancers. It is hypothesized that inhibition of TDP1 activity may enhance camptothecin sensitivity in tumors. Here, we describe the design, development, and execution of a novel assay to identify inhibitors of TDP1 present in natural product extracts. The assay was designed to address issues with fluorescent "nuisance" molecules and to minimize the detection of false-positives caused by polyphenolic molecules known to nonspecifically inhibit enzyme activity. A total of 227,905 purified molecules, prefractionated extracts, and crude natural product extracts were screened. This yielded 534 initial positives (0.23%). Secondary prioritization reduced this number to 117 (0.05% final hit rate). Several novel inhibitors have been identified showing micromolar affinity for human TDP1, including halenaquinol sulfate, a pentacyclic hydroquinone from the sponge Xestospongia sp.

Biosorption of Ni(II) by Fig Male: Optimization and Modeling Using a Full Factorial Design

The fig male (FM) is successfully used as biosorbent for Ni(2+) removal. The maximum removal efficiency (96.6%) is obtained at pH ~ 5 for a concentration of 1.70 mmol L(-1) and catalyst dose of 5 g L(-1) in less than 10 minutes. The Ni(2+) uptake follows a pseudo-second-order kinetic, the rate constants increase with increasing temperature, and an activation energy of 55.48 kJ mol(-1) is found. The thermodynamic parameters indicate a spontaneous endothermic bisorption. The isotherm data are fitted by the Langmuir and Dubinin-Radushkevich models. The former indicates a maximum Ni(2+) uptake of 0.459 mmol g(-1), which is higher than that of most biosorbents investigated to date. The FTIR spectra reveal the biosorption mechanism between Ni(2+) and FM functional groups. An empirical modeling is performed by using a 2(3) full factorial design, and a regression equation for Ni(2+) biosorption is determined. The biosorbent mass and pH are the most significant parameters affecting the Ni(2+) biosorption.

Biochemical assays for the discovery of TDP1 inhibitors

Drug screening against novel targets is warranted to generate biochemical probes and new therapeutic drug leads. TDP1 and TDP2 are two DNA repair enzymes that have yet to be successfully targeted. TDP1 repairs topoisomerase I-, alkylation-, and chain terminator-induced DNA damage, whereas TDP2 repairs topoisomerase II-induced DNA damage. Here, we report the quantitative high-throughput screening (qHTS) of the NIH Molecular Libraries Small Molecule Repository using recombinant human TDP1. We also developed a secondary screening method using a multiple loading gel-based assay where recombinant TDP1 is replaced by whole cell extract (WCE) from genetically engineered DT40 cells. While developing this assay, we determined the importance of buffer conditions for testing TDP1, and most notably the possible interference of phosphate-based buffers. The high specificity of endogenous TDP1 in WCE allowed the evaluation of a large number of hits with up to 600 samples analyzed per gel via multiple loadings. The increased stringency of the WCE assay eliminated a large fraction of the initial hits collected from the qHTS. Finally, inclusion of a TDP2 counter-screening assay allowed the identification of two novel series of selective TDP1 inhibitors.

Discovery and structure-activity relationship of novel 2,3-dihydrobenzofuran-7-carboxamide and 2,3-dihydrobenzofuran-3(2H)-one-7-carboxamide derivatives as poly(ADP-ribose)polymerase-1 inhibitors

Novel substituted 2,3-dihydrobenzofuran-7-carboxamide (DHBF-7-carboxamide) and 2,3-dihydrobenzofuran-3(2H)-one-7-carboxamide (DHBF-3-one-7-carboxamide) derivatives were synthesized and evaluated as inhibitors of poly(ADP-ribose)polymerase-1 (PARP-1). A structure-based design strategy resulted in lead compound 3 (DHBF-7-carboxamide; IC₅₀ = 9.45 μM). To facilitate synthetically feasible derivatives, an alternative core was designed, DHBF-3-one-7-carboxamide (36, IC₅₀ = 16.2 μM). The electrophilic 2-position of this scaffold was accessible for extended modifications. Substituted benzylidene derivatives at the 2-position were found to be the most potent, with 3′,4′-dihydroxybenzylidene 58 (IC₅₀ = 0.531 μM) showing a 30-fold improvement in potency. Various heterocycles attached at the 4′-hydroxyl/4′-amino of the benzylidene moiety resulted in significant improvement in inhibition of PARP-1 activity (e.g., compounds 66–68, 70, 72, and 73; IC₅₀ values from 0.718 to 0.079 μM). Compound 66 showed selective cytotoxicity in BRCA2-deficient DT40 cells. Crystal structures of three inhibitors (compounds (−)-13c, 59, and 65) bound to a multidomain PARP-1 structure were obtained, providing insights into further development of these inhibitors.

Identification of novel PARP inhibitors using a cell-based TDP1 inhibitory assay in a quantitative high-throughput screening platform

Anti-cancer topoisomerase I (Top1) inhibitors (camptothecin and its derivatives irinotecan and topotecan, and indenoisoquinolines) induce lethal DNA lesions by stabilizing Top1-DNA cleavage complex (Top1cc). These lesions are repaired by parallel repair pathways including the tyrosyl-DNA phosphodiesterase 1 (TDP1)-related pathway and homologous recombination. As TDP1-deficient cells in vertebrates are hypersensitive to Top1 inhibitors, small molecules inhibiting TDP1 should augment the cytotoxicity of Top1 inhibitors. We developed a cell-based high-throughput screening assay for the discovery of inhibitors for human TDP1 using a TDP1-deficient chicken DT40 cell line (TDP1-/-) complemented with human TDP1 (hTDP1). Any compounds showing a synergistic effect with the Top1 inhibitor camptothecin (CPT) in hTDP1 cells should either be a TDP1-related pathway inhibitor or an inhibitor of alternate repair pathways for Top1cc. We screened the 400,000-compound Small Molecule Library Repository (SMLR, NIH Molecular Libraries) against hTDP1 cells in the absence or presence of CPT. After confirmation in a secondary screen using both hTDP1 and TDP1-/- cells in the absence or presence of CPT, five compounds were confirmed as potential TDP1 pathway inhibitors. All five compounds showed synergistic effect with CPT in hTDP1 cells, but not in TDP1-/- cells, indicating that the compounds inhibited a TDP1-related repair pathway. Yet, in vitro gel-based assay revealed that the five compounds did not inhibit TDP1 catalytic activity directly. We tested the compounds for their ability to inhibit poly(ADP-ribose)polymerase (PARP) because PARP inhibitors are known to potentiate the cytotoxicity of CPT by inhibiting the recruitment of TDP1 to Top1cc. Accordingly, we found that the five compounds inhibit catalytic activity of PARP by ELISA and Western blotting. We identified the most potent compound (Cpd1) that offers characteristic close to veliparib, a leading clinical PARP inhibitor. Cpd1 may represent a new scaffold for the development of PARP inhibitors.

Synthesis and biological evaluation of new carbohydrate-substituted indenoisoquinoline topoisomerase I inhibitors and improved syntheses of the experimental anticancer agents indotecan (LMP400) and indimitecan (LMP776)

Carbohydrate moieties were strategically transported from the indolocarbazole topoisomerase I (Top1) inhibitor class to the indenoisoquinoline system in search of structurally novel and potent Top1 inhibitors. The syntheses and biological evaluation of 20 new indenoisoquinolines glycosylated with linear and cyclic sugar moieties are reported. Aromatic ring substitution with 2,3-dimethoxy-8,9-methylenedioxy or 3-nitro groups exerted strong effects on antiproliferative and Top1 inhibitory activities. While the length of the carbohydrate side chain clearly correlated with antiproliferative activity, the relationship between stereochemistry and biological activity was less clearly defined. Twelve of the new indenoisoquinolines exhibit Top1 inhibitory activity equal to or better than that of camptothecin. An advanced synthetic intermediate from this study was also used to efficiently prepare indotecan (LMP400) and indimitecan (LMP776), two anticancer agents currently under investigation in a Phase I clinical trial at the National Institutes of Health.

Synthesis and biological evaluation of indenoisoquinolines that inhibit both tyrosyl-DNA phosphodiesterase I (Tdp1) and topoisomerase I (Top1)

Tyrosyl-DNA phosphodiesterase I (Tdp1) plays a key role in the repair of damaged DNA resulting from the topoisomerase I (Top1) inhibitor camptothecin and a variety of other DNA-damaging anticancer agents. This report documents the design, synthesis, and evaluation of new indenoisoquinolines that are dual inhibitors of both Tdp1 and Top1. Enzyme inhibitory data and cytotoxicity data from human cancer cell cultures were used to establish structure-activity relationships. The potencies of the indenoisoquinolines against Tdp1 ranged from 5 μM to 111 μM, which places the more active compounds among the most potent known inhibitors of this target. The cytotoxicity mean graph midpoints ranged from 0.02 to 2.34 μM. Dual Tdp1-Top1 inhibitors are of interest because the Top1 and Tdp1 inhibitory activities could theoretically work synergistically to create more effective anticancer agents.

5-Arylidenethioxothiazolidinones as inhibitors of tyrosyl-DNA phosphodiesterase I

Tyrosyl-DNA phosphodiesterase I (Tdp1) is a cellular enzyme that repairs the irreversible topoisomerase I (Top1)-DNA complexes and confers chemotherapeutic resistance to Top1 inhibitors. Inhibiting Tdp1 provides an attractive approach to potentiating clinically used Top1 inhibitors. However, despite recent efforts in studying Tdp1 as a therapeutic target, its inhibition remains poorly understood and largely underexplored. We describe herein the discovery of arylidene thioxothiazolidinone as a scaffold for potent Tdp1 inhibitors based on an initial tyrphostin lead compound 8. Through structure-activity relationship (SAR) studies we demonstrated that arylidene thioxothiazolidinones inhibit Tdp1 and identified compound 50 as a submicromolar inhibitor of Tdp1 (IC₅₀ = 0.87 μM). Molecular modeling provided insight into key interactions essential for observed activities. Some derivatives were also active against endogenous Tdp1 in whole cell extracts. These findings contribute to advancing the understanding on Tdp1 inhibition.

Synthesis and biological evaluation of the first dual tyrosyl-DNA phosphodiesterase I (Tdp1)-topoisomerase I (Top1) inhibitors

Substances with dual tyrosyl-DNA phosphodiesterase I-topoisomerase I inhibitory activity in one low molecular weight compound would constitute a unique class of anticancer agents that could potentially have significant advantages over drugs that work against the individual enzymes. The present study demonstrates the successful synthesis and evaluation of the first dual Top1-Tdp1 inhibitors, which are based on the indenoisoquinoline chemotype. One bis(indenoisoquinoline) had significant activity against human Tdp1 (IC(50) = 1.52 ± 0.05 μM), and it was also equipotent to camptothecin as a Top1 inhibitor. Significant insights into enzyme-drug interactions were gained via structure-activity relationship studies of the series. The present results also document the failure of the previously reported sulfonyl ester pharmacophore to confer Tdp1 inhibition in this indenoisoquinoline class of inhibitors even though it was demonstrated to work well for the steroid NSC 88915 (7). The current study will facilitate future efforts to optimize dual Top1-Tdp1 inhibitors.

[Echographic monitoring of post-hemorrhagic ventricular dilatations in premature newborn infants. Value of the determination of a ventricular index]

The target of this work was the determination of a quantifiable measurement of the ventricular dilatation with an index during the ultrasonographic supervision of intraventricular hemorrhages (IVH) in premature infants. An investigation by cerebral ultrasonography through the fontanelles was performed in 63 non hypotrophic prematures. Thirty-one children (mean gestational age 32 +/- 1.8 weeks) had an IVH. All had ventricular dilatation at one time during evolution. The 32 other children (mean gestational age 34 +/- 2 weeks) showed normal ultrasonographic data and a ventricular index between 0.15 and 0.25 (mean 0.23 +/- 0.02). Post-hemorrhagic ventricular dilatation can be classified into 3 stages: slight dilatation: ventricular index between 0.26 and 0.30; moderate dilatation: ventricular index between 0.31 and 0.40; severe dilatation: ventricular index greater than 0.40. The use of a ventricular index allows precise following of the ventricular dilatation during the supervision of intraventricular hemorrhages.

[Non invasive measurement of the cerebral blood flow in infants with hydrocephalus]

The present study was undertaken to verify by a non invasive Doppler technique the effect of ventricular dilatation on cerebral blood flow in infants with hydrocephalus. The measurement of pulsatile flow in cerebral arteries is also a valuable parameter for determination of optimal timing of corrective intervention.