Novel LIPA-Targeted Therapy for Treating Ovarian Cancer

Ovarian cancer (OCa) is the most lethal form of gynecologic cancer, and the tumor heterogeneities at the molecular, cellular, and tissue levels fuel tumor resistance to standard therapies and pose a substantial clinical challenge. Here, we tested the hypothesis that the heightened basal endoplasmic reticulum stress (ERS) observed in OCa represents an exploitable vulnerability and may overcome tumor heterogeneity. Our recent studies identified LIPA as a novel target to induce ERS in cancer cells using the small molecule ERX-41. However, the role of LIPA and theutility of ERX-41 to treat OCa remain unknown. Expression analysis using the TNMplot web tool, TCGA data sets, and immunohistochemistry analysis using a tumor tissue array showed that LIPA is highly expressed in OCa tissues, compared to normal tissues. ERX-41 treatment significantly reduced the cell viability and colony formation ability and promoted the apoptosis of OCa cells. Mechanistic studies revealed a robust and consistent induction of ERS markers, including CHOP, elF2α, PERK, and ATF4, upon ERX-41 treatment. In xenograft and PDX studies, ERX-41 treatment resulted in a significant reduction in tumor growth. Collectively, our results suggest that ERX-41 is a novel therapeutic agent that targets the LIPA with a unique mechanism of ERS induction, which could be exploited to treat heterogeneity in OCa.

Targeting PELP1 oncogenic signaling in TNBC with the small molecule inhibitor SMIP34

PURPOSE

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer. Oncogenic PELP1 is frequently overexpressed in TNBC, and it has been demonstrated that PELP1 signaling is essential for TNBC progression. The therapeutic utility of targeting PELP1 in TNBC, however, remains unknown. In this study, we investigated the effectiveness of SMIP34, a recently developed PELP1 inhibitor for the treatment of TNBC.

METHODS

To ascertain the impact of SMIP34 treatment, we used seven different TNBC models for testing cell viability, colony formation, invasion, apoptosis, and cell cycle analysis. Western blotting and RT-qPCR were used to determine the mechanistic insights of SMIP34 action. Using xenograft and PDX tumors, the ability of SMIP34 in suppressing proliferation was examined both ex vivo and in vivo.

RESULTS

TNBC cells' viability, colony formation, and invasiveness were all decreased by SMIP34 in in vitro cell-based assays, while apoptosis was increased. SMIP34 treatment promoted the degradation of PELP1 through the proteasome pathway. RT-qPCR analyses confirmed that SMIP34 treatment downregulated PELP1 target genes. Further, SMIP34 treatment substantially downregulated PELP1 mediated extranuclear signaling including ERK, mTOR, S6 and 4EBP1. Mechanistic studies confirmed downregulation of PELP1 mediated ribosomal biogenesis functions including downregulation of cMyc and Rix complex proteins LAS1L, TEX-10, and SENP3. The proliferation of TNBC tumor tissues was decreased in explant experiments by SMIP34. Additionally, SMIP34 treatment markedly decreased tumor progression in both TNBC xenograft and PDX models.

CONCLUSIONS

Together, these findings from in vitro, ex vivo, and in vivo models show that SMIP34 may be a useful therapeutic agent for inhibiting PELP1 signaling in TNBC.

Abstract 3986: Novel LIPA targeted therapy for treating ovarian cancer

BACKGROUND: Ovarian cancer (OCa) is the deadliest of all gynecologic cancers in the United States. Currently approved therapies have improved OCa survival for clinically localized disease, however, the majority (~90%) of patients with high-grade serous OCa (HGSOC) experience relapse with incurable metastases. There is a dire need for new therapeutic approaches. We hypothesized that the high basal endoplasmic reticulum stress (ERS) in OCa represents a critical and targetable vulnerability and may overcome the tumor heterogeneity. The objective of this project is to exploit increased ERS in ovarian cancer cells by engaging the novel target LIPA using the unique compound ERX-41.

METHODS: The utility of ERX-41 as a new therapy was evaluated using MTT and CellTiter-Glo Cell Viability Assays. We used multiple established and patient derived OCa cell lines. The effect of ERX-41 on the Cell viability of patient-derived organoids (PDO) was measured using CellTiter-Glo 3D Assay. Long term effects of ERX-41 on cell survival were measured using colony formation assays. Apoptosis was measured using Annexin V and Caspase-Glo® 3/7 Assays. Cell cycle analysis was analyzed by Flow Cytometry. Mechanistic studies were done using LIPA knockout (KO) cells, RT-qPCR, and western blotting. Status of LIPA in OCa was determined using TNMplot database. In vivo efficacy of ERX-41 was tested using both cell line derived (CDX) and patient derived (PDXs) xenografts.

RESULTS: TNM plot results showed that LIPA is highly expressed in OCa tumors compared to normal tissues and LIPA expression correlated with clinical grade. Kaplan-Meier plotter analyses of TCGA data revealed that LIPA expression is negatively correlated with overall survival in OCa patients. MTT and CellTitre-Glo assay results showed that ERX-41 significantly reduced the cell viability of both established and primary OCa cells, and PDO’s with an IC50 of ~500nM. ERX-41 treatment also significantly reduced the cell survival, increased S-phase arrest, and promoted apoptosis of OCa cells. A time course study revealed a robust and consistent induction of ERS markers (CHOP and sXBP1) in OCa cells by ERX-41 within 4h. Western blotting analyses also confirmed increased expression of ERS markers including CHOP, elF2α, PERK, and ATF4 upon ERX-41 treatment confirming that ERX-41 induces ERS. In xenograft studies, ERX-41 treatment resulted in ~66% reduction of tumor volume measured by Xenogen-IVIS. Further, in studies using PDX tumors, treatment with ERX-41 resulted in a significant reduction (~60%) of tumor volume and tumor weight.

CONCLUSION: Collectively, our results suggest that ERX-41 is a novel therapeutic agent that targets the LIPA with a unique mechanism of action and implicate ERX-41 binding to LIPA induces ER stress, and apoptosis of OCa cells. Further molecular characterization of how ERX-41 binding to LIPA induces ER stress in OCa cells is ongoing.

Citation Format: Alexia B. Collier, Suryavathi Viswanadhapalli, Tae-Kyung Lee, Kara Kassees, Karla Parra, Gaurav Sharma, Tanner Reese, Michael Hsieh, Xihui Liu, Xue Yang, Behnam Ebrahimi, Uday P. Pratap, Rahul Gopalam, Chia Yuan Chen, Scott Terry Elmore, Gangadhara Reddy Sareddy, Edward R. Kost, Jung-Mo Ahn, Ganesh V. Raj, Ratna K. Vadlamudi. Novel LIPA targeted therapy for treating ovarian 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 3986.

Abstract 4966: Targeting LIF/LIFR autocrine loops with EC359 in ovarian cancer: A novel LIFR targeted therapy

Background: Of all gynecologic cancers, ovarian cancer (OCa) has the highest mortality rates. Nearly 90% of patients who receive standard surgical and cytotoxic treatment experience disease recurrence. Leukemia inhibitory factor (LIF) and its receptor LIFR are implicated in the progression of several cancers. A knowledge gap exists on whether LIF/LIFR plays a role in the evolution of OCa. We recently developed EC359, a first-in-class LIFR inhibitor. Here, we examined whether autocrine loops of LIF/LIFR contribute to OCa progression and tested the utility of EC359 as a potential targeted therapy.

Methods: Eighteen different OCa model cells, both established and primary, were used to profile the expression of LIF and LIFR. Cell viability, colony formation, apoptosis, and reporter assays were used to assess EC359 impact on OCa cells. Mechanistic studies were carried out using RNA-seq and RT-qPCR analysis. Using cell-based xenografts, syngeneic xenografts, patient derived organoids (PDO), and patient derived xenograft (PDX) models, the effectiveness of LIFR inhibitor EC359 as a targeted therapy was examined.

Results: Kaplan-Meier survival analysis (KMplot) revealed increased expression of LIF and LIFR was linked to poor progression-free survival in OCa patients. The levels of LIF and LIFR were considerably greater in OCa chemotherapy non-responders than responders. We validated the existence of LIF/LIFR autocrine signaling using 18 distinct OCa cells. Treatment with the LIFR inhibitor EC359 dramatically decreased OCa cell viability, cell survival and increased apoptosis, with an IC50 of 5 to 50 nM. The activation of STAT3, mTOR, AKT, and p42/44 MAPKs as well as other downstream LIFR signaling was markedly decreased by EC359 treatment. Treatment with EC359 also decreased the stemness of OCa cells, slowed PDO development, and sensitized chemotherapy-resistant OCa cells to chemotherapy. One of the significant pathways elevated by EC359, according to RNA-seq data, is the regulation of apoptosis. In six different cell-based xenografts and PDX tumors, we demonstrated that the EC359 at 5mg/kg dose significantly reduced the OCa xenograft growth. In comparison to the vehicle control, the tumor volume was significantly reduced by EC359 treatment of murine ID8 xenografts in C57BL6 mice. Our findings indicated that EC359 had both intrinsic and extrinsic effects on tumors. Tumor-associated macrophages (TAMs) with a significant M1 polarity (CD11b+Gr1-CD68high/phosphoSTAT1+/cMAF-) and robust tumor infiltration by (CD45+) leukocytes were enhanced with EC359 therapy of ID8 xenograft tumors. Importantly, normal T, B, and other immune cells in the blood demonstrated that EC359 had no effect on immune cell homeostasis.

Conclusions: Together, our findings support the existence of LIF/LIFR autocrine loops, and EC359 is a viable treatment option for OCa.

Citation Format: Behnam Ebrahimi, Suryavathi Viswanadhapalli, Uday P. Pratap, Rahul Gopalam, Xue Yang, Bindhu Santhamma, Swapna Konda, Xiaonan Li, Hui Yan, Gangadhara R. Sareddy, Zhenming Xu, Edward R. Kost, Rajeshwar R. Tekmal, Hareesh B. Nair, Ratna K. Vadlamudi. Targeting LIF/LIFR autocrine loops with EC359 in ovarian cancer: A novel LIFR targeted therapy. [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 4966.

Abstract 4813: ERX-208 as a novel therapeutic for treating ovarian cancer by enhancing endoplasmic reticulum stress

Background: Ovarian cancer (OCa) is the deadliest of all gynecologic cancers in the United States. Despite initial response to chemotherapy, most OCa patients become chemo resistant and progress to metastatic disease. Here, we tested the hypothesis that the high basal level of endoplasmic reticulum stress (ERS) in OCa represents a critical vulnerability and drugs that further aggravate this already engaged system in OCa may exhaust its protective features and contribute to apoptosis induction. The objective of this proposal is to identify a hit compound that enhances ERS in OCa and to conduct mechanistic studies.

Methods: We synthesized a small library of >200 chemically distinct oligobenzamide analogs with maintenance of the chemical backbone but altered R groups of ERX-11. We performed the primary screening of this library to evaluate the induction of mRNA levels of two canonical ERS/UPR (unfolded protein response) genes- sXBP1 and CHOP. Biological activity of ERX-208 was validated using multiple OCa cells. Mechanistic studies were conducted using CRISPR/Cas9 KO, Western blotting, reporter gene assays, IHC and RNA-seq analysis. PK (pharmacokinetics) and toxicity studies were done using C57BL/6 mice. Cell line-derived xenografts (CDXs), patient-derived xenografts (PDXs), patient-derived explants (PDEs), and patient-derived organoids (PDO) were used for preclinical evaluation.

Results: From a screen of a curated ERX-11 derived oligobenzamide library, we identified a hit compound, ERX-208 that potently (IC50~100nM) induces ERS/UPR and apoptosis in multiple OCa cells in vitro. CRISPR KO screen identified the lysosomal acid lipase A (LIPA) protein as the critical target of ERX-208. LIPA KO abrogates response to ERX-208, while reconstitution of LIPA restores ERX-208 response. The time course studies showed a robust and consistent induction (>15-fold CHOP, and >10-fold sXBP1) by ERX-208 treatment within 24h. We confirmed induction of classic UPR components peIF2α, CHOP and LC3B using Western blotting in multiple OCa cells. Functionally, ERX-208 causes growth inhibition of OCa cells, as noted by MTT cell viability assays using 15 OCa cells with an IC50 of ~50-100nM. The activity of ERX-208 is distinct among oligobenzamides as ERX-11 has limited/no activity against OCa cells. RNA-seq analysis confirmed that ERX-208 induces significant ERS, UPR, and apoptosis. Further, ERX-208 reduced the growth of OCa PDO’s in vitro, PDEs ex vivo and CDXs and PDXs in vivo. ERX-208 treatment did not show any signs of toxicity and body weight of mice was not affected. IHC analyses showed increased activation of ERS/UPR markers such as GRP78, p-PERK and decreased proliferation measured by Ki67.

Conclusions: Collectively, our results demonstrated the utility of ERX-208 and will establish a novel therapeutic paradigm in OCa that overcomes tumor heterogeneity by targeting LIPA and enhancing ERS leading to apoptosis.

Citation Format: Suryavathi Viswanadhapalli, Tae-Kyung Lee, Kara Kassees, Gaurav Sharma, Rahul Gopalam, Karla Parra, Tanner Reese, Michael Hsieh, Uday P. Pratap, Xue Yang, Behnam Ebrahimi, Chia Yuan Chen, Scott Terry Elmore, Christian Cervantes, Zhenming Xu, Edward Kost, Gangadhara Reddy Sareddy, Rajeshwar Rao Tekmal, Jung-Mo Ann, Ganesh V. Raj, Ratna K. Vadlamudi. ERX-208 as a novel therapeutic for treating ovarian cancer by enhancing endoplasmic reticulum stress. [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 4813.

A first-in-class inhibitor of ER coregulator PELP1 targets ER+ breast cancer

Most patients with estrogen receptor alpha-positive breast cancers (ER+ BC) initially respond to treatment but eventually develop therapy resistance with disease progression. Overexpression of oncogenic ER coregulators, including proline, glutamic acid, and leucine-rich protein 1 (PELP1), are implicated in BC progression. The lack of small molecules that inhibits PELP1 represents a major knowledge gap. Here, using a yeast-two-hybrid screen, we identified novel peptide inhibitors of PELP1 (PIPs). Biochemical assays demonstrated that one of these peptides, PIP1, directly interacted with PELP1 to block PELP1 oncogenic functions. Computational modeling of PIP1 revealed key residues contributing to its activity and facilitated the development of a small molecule inhibitor of PELP1, SMIP34, and further analyses confirmed that SMIP34 directly bound to PELP1. In BC cells, SMIP34 reduced cell growth in a PELP1-dependent manner. SMIP34 inhibited proliferation of not only wild-type (WT) but also mutant (MT) ER+ and therapy-resistant (TR) BC cells, in part by inducing PELP1 degradation via the proteasome pathway. RNA-seq analyses showed that SMIP34 treatment altered the expression of genes associated with estrogen response, cell cycle, and apoptosis pathways. In cell line-derived and patient-derived xenografts of both WT- and MT- ER+ BC models, SMIP34 reduced proliferation and significantly suppressed tumor progression. Collectively, these results demonstrate SMIP34 as a first-in-class inhibitor of oncogenic PELP1 signaling in advanced BC.

Abstract 648: A novel small molecule targeting oncogenic PELP1 demonstrates anti-tumor activity in wild-type and mutant ER-positive breast cancer

A significant proportion of estrogen receptor positive breast cancers (ER+BC) will initially respond to treatment, but many eventually develop therapy resistance (TR-BC), and progress to incurable metastases. Oncogenic ER coregulators overexpressed in BC can contribute to constitutive, ligand-independent and ligand-dependent signaling which drives growth, resistance to therapy and metastasis. Proline-, glutamic acid, and leucine-rich protein 1 (PELP1), is a known coregulator that plays a critical role in ER oncogenic functions. Its expression is deregulated in BC and is a prognostic indicator of poor BC survival. The lack of a small molecule inhibitor that directly targets PELP1 represents a major knowledge gap. Therefore, we conducted a large scale peptide library screening and identified novel Peptide Inhibitor of PELP1 (PIP1). We demonstrated that PIP1 directly interacts with PELP1, promotes its degradation and has the potential to block PELP1 oncogenic functions in vitro. Using innovative peptidomimetic technology, we modeled PIP1 and synthesized several derivatives as Small Molecule Inhibitors of PELP1 (SMIPs). Using MTT assay and multiple BC cell lines, we identified a lead compound, SMIP34 with an IC50 of 5-10µM and with minimal effect on human mammary epithelial cells. SMIP34 in vitro activity was assessed by colony formation and Matrigel invasion assays. Knockdown of PELP1 using shRNA in BC cells significantly reduced SMIP34 activity, indicating target specificity. Further, MST and biotin-SMIP34 pulldown confirmed direct binding of SMIP34 to PELP1. Using ER+WT, mtER (mutant ER), and TR-BC cell lines we demonstrated that SMIP34 exhibits antiproliferative effects and reduces invasiveness. Mechanistic studies using Western blot analysis confirmed that SMIP34 binding to PELP1 contributes to its degradation via the proteasome pathway. Thus MG132 treatment attenuated SMIP34 mediated degradation. RTqPCR analyses confirmed SMIP34 treatment reduced expression of PELP1 target genes. RNAseq analyses showed SMIP34 treatment altered the expression of genes associated with Estrogen response, Cell cycle and Apoptosis pathways. Cell cycle analyses revealed SMIP34 treatment promoted S phase arrest of BC cell lines. Using ER+WT, mtER, and PDX tumor tissues ex vivo, we demonstrated that SMIP34 significantly decreased tumor proliferation as measured by Ki67 staining. Further, SMIP34 (20mg/kg/IP) treatment in vivo significantly reduced tumor progression in mouse models of ER+WT, mtER, and mtER patient-derived xenograft BC. Our results using in vitro, ex vivo, and in vivo models showcase SMIP34 as a first-in-class inhibitor of oncogenic PELP1 signaling and may serve as a potential therapeutic molecule for treating ER+, mtER, and TR-BC. Supported by NIH 1F31CA257298 (KA) and VA I01BX004545 (RV).

Citation Format: Kristin Ann Altwegg, Monica Mann, Dimple Chakravarty, Zexuan Liu, Junhao Liu, Uday P. Pratap, Behnam Ebrahimi, John R. Sanchez, Ben H. Park, Hariprasad Vankayalapati, Gangadhara R. Sareddy, Suryavathi Viswanadhapalli, Ratna K. Vadlamudi. A novel small molecule targeting oncogenic PELP1 demonstrates anti-tumor activity in wild-type and mutant ER-positive breast cancer [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 648.

SETDB1 interactions with PELP1 contributes to breast cancer endocrine therapy resistance

Background

Methyltransferase SETDB1 is highly expressed in breast cancer (BC), however, the mechanisms by which SETDB1 promotes BC progression to endocrine therapy resistance remains elusive. In this study, we examined the mechanisms by which SETDB1 contribute to BC endocrine therapy resistance.

Methods

We utilized therapy sensitive (MCF7 and ZR75), therapy resistant (MCF7-TamR, MCF7-FR, MCF7-PELP1cyto, MCF7-SETDB1) estrogen receptor alpha positive (ER⁺)BC models and conducted in vitro cell viability, colony formation, 3-dimensional cell growth assays to investigate the role of SETDB1 in endocrine resistance. RNA-seq of parental and SETDB1 knock down ER⁺ BC cells was used to identify unique pathways. SETDB1 interaction with PELP1 was identified by yeast-two hybrid screen and confirmed by immunoprecipitation and GST-pull down assays. Mechanistic studies were conducted using Western blotting, reporter gene assays, RT-qPCR, and in vitro methylation assays. Xenograft assays were used to establish the role of PELP1 in SETDB1 mediated BC progression.

Results

RNA-seq analyses showed that SETDB1 regulates expression of a subset of estrogen receptor (ER) and Akt target genes that contribute to endocrine therapy resistance. Importantly, using yeast-two hybrid screen, we identified ER coregulator PELP1 as a novel interacting protein of SETDB1. Biochemical analyses confirmed SETDB1 and PELP1 interactions in multiple BC cells. Mechanistic studies confirmed that PELP1 is necessary for SETDB1 mediated Akt methylation and phosphorylation. Further, SETDB1 overexpression promotes tamoxifen resistance in BC cells, and PELP1 knockdown abolished these effects. Using xenograft model, we provided genetic evidence that PELP1 is essential for SETDB1 mediated BC progression in vivo. Analyses of TCGA datasets revealed SETDB1 expression is positively correlated with PELP1 expression in ER⁺ BC patients.

Conclusions

This study suggests that the PELP1/SETDB1 axis play an important role in aberrant Akt activation and serves as a novel target for treating endocrine therapy resistance in breast cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13058-022-01520-4.

Abstract P5-10-01: Leukemia inhibitory factor receptor inhibition reduces obesity driven progression of triple negative breast cancer

Background: The obesity epidemic is rapidly increasing in the USA and obese women are at a higher likelihood of developing triple negative breast cancer (TNBC). Several studies implicated the importance of the breast microenvironment on the aggressive cancer biology especially obese microenvironment. However, the underlying mechanism(s) by which obesity contributes to the progression of TNBC remains unclear. The objective of this study is to test a novel concept that obesity upregulates leukemia inhibitory factor receptor (LIFR) oncogenic signaling in TNBC and test whether LIFR inhibition blocks TNBC progression. Methods: Established TNBC cell lines were co-cultured with human primary adipocytes or incubated with adipocyte conditioned medium or with high glucose (HG) followed by treatment with LIFR inhibitor EC359. The effect of adiposity on TNBC cells was determined using cell viability, colony formation, and invasion assays. Mechanistic studies were performed using CRISPR/Cas9 KO of LIFR, Western blotting, RT-qPCR, and reporter gene assays. Utility of LIFR inhibitor EC359 was tested using xenografts, and patient derived organoid (PDO) models. Results: Treatment of TNBC cells with adipose conditions or HG increased the proliferation and invasion of TNBC cells. Western blot and RT-qPCR analyses confirmed that increased expression of LIFR correlated with enhanced downstream LIFR signaling such as STAT3 and subsequent activation of STAT3 target genes. CRISPR KO of LIFR or treatment of TNBC cells with EC359 significantly reduced the cell viability, colony formation and invasion under adipose conditions. Western blotting results showed that co-culture with adipocytes significantly enhanced LIFR downstream signaling in TNBC model cells and is effectively blocked by LIFR KO or EC359 treatment. Further, EC359 treatment blocked the adipose environment mediated growth of organoids. Importantly, co-implantation of adipocytes significantly enhanced TNBC xenograft tumor growth, however treatment with EC359 significantly attenuated adipocyte induced TNBC progression. Conclusions: Collectively, these results suggest that adiposity contributes to increased TNBC cell growth via upregulation of the LIF/LIFR pathway. The LIF/LIFR axis represents a potential therapeutic target for adiposity driven TNBC and the LIFR inhibitor EC359 could be used as a new therapeutic agent to treat obesity associated TNBC.

Citation Format: Suryavathi Viswanadhapalli, Uday P Pratap, Behnam Ebrahimi, Logan Blankenship, Jaitri Joshi, Zexuan Liu, Kristin A Altwegg, Xiaonan Li, Gangadhara R Sareddy, Bindu Santhamma, Swapna Konda, Manjeet Rao, Edward Kost, Rajeshwar R Tekmal, Hareesh B Nair, Ratna K Vadlamudi. Leukemia inhibitory factor receptor inhibition reduces obesity driven progression of triple negative breast cancer [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-10-01.

LIFR inhibition enhances the therapeutic efficacy of HDAC inhibitors in triple negative breast cancer

Histone deacetylase inhibitors (HDACi) are identified as novel therapeutic agents, however, recent clinical studies suggested that they are marginally effective in treating triple negative breast cancer (TNBC). Here, we show that first-in-class Leukemia Inhibitory Factor Receptor (LIFRα) inhibitor EC359 could enhance the therapeutic efficacy of HDACi against TNBC. We observed that both targeted knockdown of LIFR with CRISPR or treatment with EC359 enhanced the potency of four different HDACi in reducing cell viability, cell survival, and enhanced apoptosis compared to monotherapy in TNBC cells. RNA-seq studies demonstrated oncogenic/survival signaling pathways activated by HDACi were attenuated by the EC359 + HDACi therapy. Importantly, combination therapy potently inhibited the growth of TNBC patient derived explants, cell derived xenografts and patient-derived xenografts in vivo. Collectively, our results suggest that targeted inhibition of LIFR can enhance the therapeutic efficacy of HDACi in TNBC.

Phase I/II trial of palbociclib, pembrolizumab and letrozole in patients with hormone receptor-positive metastatic breast cancer

BACKGROUND

CDK4/6 inhibitors modulate immune response in breast cancer. This phase I/II trial was designed to test the safety and efficacy of palbociclib, pembrolizumab and letrozole in women with hormone receptor positive (HR⁺) human epidermal growth factor receptor 2 negative (HER2^-) metastatic breast cancer (MBC).

PATIENTS AND METHODS

Women with stage IV HR⁺ HER2^- MBC were enrolled and treated with palbociclib, pembrolizumab and letrozole. Primary end-points were safety, tolerability and efficacy.

RESULTS

Between November 2016 and July 2020, 23 patients were enrolled with 20 evaluable for response, including 4 patients in cohort 1 and 16 patients in cohort 2. Cohort 1 median age was 48 years (33-70) and cohort 2 median age was 55 (37-75). Cohort 1 closed early due to limited accrual. Grade III-IV adverse events were neutropenia (83%), leucopaenia (65%), thrombocytopenia (17%) and elevated liver enzymes (17%). In cohort 1, 50% achieved a partial response (PR) and 50% had stable disease (SD). In cohort 2, 31% achieved complete response (CR), 25% had PR and 31% had SD by Response Evaluation Criteria in Solid Tumours version 1.1. Median progression-free survival was 25.2 months (95% confidence interval [CI] 5.3, not reached) and median overall survival was 36.9 months (95% CI 36.9, not reached) in cohort 2 with a median follow-up of 24.8 months (95% CI 17.1, not reached). A correlative immune biomarker analysis was published separately.

CONCLUSION

The combination of palbociclib, pembrolizumab and letrozole is well tolerated, and a complete response rate of 31% was identified in HR⁺ MBC patients who received this combination as front-line therapy. Confirmatory trials are required to better understand the immune-priming effects of CDK4/6 inhibitors.

LIF/LIFR oncogenic signaling is a novel therapeutic target in endometrial cancer

Endometrial cancer (EC) is the fourth most common cancer in women. Advanced-stage EC has limited treatment options with a poor prognosis. There is an unmet need for the identification of actionable drivers for the development of targeted therapies in EC. Leukemia inhibitory factor receptor (LIFR) and its ligand LIF play a major role in cancer progression, metastasis, stemness, and therapy resistance. However, little is known about the functional significance of the LIF/LIFR axis in EC progression. In this study using endometrial tumor tissue arrays, we identified that expression of LIF, LIFR is upregulated in EC. Knockout of LIFR using CRISPR/Cas9 in two different EC cells resulted in a significant reduction of their cell viability and cell survival. In vivo studies demonstrated that LIFR-KO significantly reduced EC xenograft tumor growth. Treatment of established and primary patient-derived EC cells with a novel LIFR inhibitor, EC359 resulted in the reduction of cell viability with an IC50 in the range of 20-100 nM and induction of apoptosis. Further, treatment with EC359 reduced the spheroid formation of EC cancer stem cells and reduced the levels of cancer stem cell markers SOX2, OCT4, NANOG, and Axin2. Mechanistic studies demonstrated that EC359 treatment attenuated the activation of LIF-LIFR driven pathways, including STAT3 and AKT/mTOR signaling in EC cells. Importantly, EC359 treatment resulted in a significant reduction of the growth of EC patient-derived explants ex vivo, EC cell line-derived xenografts, and patient-derived xenografts in vivo. Collectively, our work revealed the oncogenic potential of the LIF/LIFR axis in EC and support the utility of LIFR inhibitor, EC359, as a novel targeted therapy for EC via the inhibition of LIF/LIFR oncogenic signaling.

P–125 Evaluation of N-acetylcysteine (NAC) effect on in vitro culture of immature mouse testis following vitrification

Study question

Can the Culture of cryopreserved immature mouse testicular tissue in the presence of NAC improves the developmental process and prevent apoptosis induction during the culture?

Summary answer

An appropriate dosage of NAC in the culture medium of immature mouse testicular tissue was associated with increased cell survival and spermatogonia stem cell regeneration.

What is known already

Spermatogonial stem cells (SSCs) are the most advanced type of stem cells in the testes of prepubertal boys which are the main targets of oncological treatments. Therefore, the only possible alternative to maintain fertility in prepubertal boys is to preserve SSCs before their depletion by cryopreserving the testicular tissue. Despite the possibility of obtaining viable spermatozoa using cryopreserved testicular tissue cultivated in vitro,cryopreservation methods and damages caused by the culture procedure would be obstacles for maintaining the testicular tissueand it seems that optimizing the culture condition is vital.

Study design, size, duration

Testis tissues were harvested from 6-days-old immature NMRI male mice (n = 100) after cervical dislocation and vitrified. After 3 days testicular biopsies were warmed and distributed into control, culture Ӏ (not supplemented with NAC) and culture ӀӀ (supplemented with NAC) groups. To determine the appropriate NAC concentration 8 different dosages of NAC were evaluated in terms of cell survival and the best dose, a culture medium containing 125mmol/L NAC was selected to continue the study.

Participants/materials, setting, methods

Vitrified-warmed fragments (2mm3) obtaining from immature NMRI mice were cultured in vitro for 7 days on agar gel. The effects of culture conditions were assessed by Morphological evaluation of seminiferous tubules (using Hematoxylin-eosin staining). Cell viability, protein expression (caspase–3), and gene expression (Bax, Bcl2, Caspase–3, plzf) were evaluated by flow cytometry, immunofluorescence staining, and real time polymerase chain reaction respectively. Additionally, Malondialdehyde (MDA) concentration in the culture medium was measured by MAD Assay Kit.

Main results and the role of chance

Significant (p < 0.01) increase in cell viability was observed in the culture ӀӀ group after 7 days of culture compared to the culture Ӏ. Bax/Bcl2 ratio was significantly (p < 0.01) lower in the culture ӀӀ group compared to the control and culture Ӏ group. The expression of caspase–3 showed a significant (p < 0.001) increase in the culture ӀӀ group while immunofluorescence analysis showed low expression of it in all groups. These results were consistent with the high level of Bcl2expression that inhibited Caspase–3 expression and consequently the inhibition of apoptosis, and on the other hand, the presence of NAC showed that plzf expressions significantly (p < 0.001) increased in culture ӀӀ group compared to the control and culture Ӏ group. Although the presence of NAC did not inhibit all the deleterious effects of culture medium on tissue morphology, NAC was able to maintain better integrity of tissue and seminiferous tubules within central regions compared to the group without NAC. The decrease in MDA level in the presence of NAC (culture ӀӀ) was also a good indicator to confirm the desired results obtained from the presence of NAC in the culture medium.

Limitations, reasons for caution

Although the findings of the study were satisfactory in mice tissue after 1 week of culture, it is essential to replicate the experiments using human tissue and evaluate the quality and reproductive potential of surviving spermatogonia after long-term storage to become clinically applicable.

Wider implications of the findings: This study highlights the necessity for further experiments to improve the testicular tissue culture conditions for better spermatogonial survival and differentiation to sperm, as the prepubertal fertility restoration methods are promising to be implemented in the clinic in the near future.

Trial registration number

Not applicable

O-218 The effect of mTOR activation on human primordial follicle activation during in-situ culture

Study question

What is the effect of mTOR pathway activation on human primordial follicles in-situ activation and subsequent development following tissue cryopreservation?

Summary answer

Temporary treatment of cryopreserved human ovarian tissue with mTOR activators cause the initiation of primordial follicle development and influence steroidogenesis.

What is known already

In-vitro activation of primordial follicles to produce mature oocytes provides an alternative technique for fertility preservation. The employment of different stimulators of PI3K pathway has been successfully used to activate resting follicles during culture or prior to grafting in patients with premature ovarian insufficiency. The addition of phosphatidic acid (PA) and propranolol (PP), as mTOR stimulators, in the culture medium has promoted primordial follicle activation morphologically in mouse and human ovaries. Molecular and functional evaluations of primordial follicle activation after treatment with the mentioned stimulators has not been conducted.

Study design, size, duration

Ovarian tissues which were donated from 6 transsexual patients (23-35 years old), were dissected and cryopreserved with slow-freezing technique. After thawing, they were cut into 1x1x1 mm fragments and incubated with different stimulators in three groups: 1) Control (without stimulators), 2) PA (200µM), and 3) PA+PP (200µM & 50µM respectively). In groups two and three, ovarian fragments were cultured for 24 hours in presence of stimulators and then cultured for additional 6 days without stimulators.

Participants/materials, setting, methods

The cultured ovarian fragments were directly processed for Hematoxylin and Eosin staining and Western blot analysis. The proportion of morphologically normal and degenerated primordial and growing follicles and 17β-estradiol (E2) level in the culture medium were compared after 1 and 7 days of culture to assess follicular development and function. Western blot analysis for phosphorylated and non-phosphorylated status of FOXO3a and RSP6 proteins expression were compared after 24 hours of incubation.

Main results and the role of chance

The proportion of primordial and growing follicles were not significantly different in the experimental groups after 24 hours of incubation with either of the stimulators. Western blot analyses indicated a significant reduction of FOXO3a in the PA+PP group compared to the control group. The phosphorylation level of RPS6 protein did not significantly change in either of the groups. The proportion of transitional follicles were significantly higher in the PA group compared to other groups after 7 days of culture. The E2 secretion level was significantly higher at the last day of culture compared to day 1 for all groups. At the end of the culture period, E2 levels was significantly higher in both PA and PA+PP groups compared to the control group.

Limitations, reasons for caution

Due to ovarian fragmentation before culture, the HIPPO pathway downstream molecules should have also been evaluated by western blot, which was not contributed in this study.

Wider implications of the findings

The results demonstrate the beneficial effect of mTOR signaling to accelerate early primordial follicle recruitment in cryopreserved-thawed human ovarian fragments.

Trial registration number

not applicable

Abstract 1253: Therapeutic targeting of endometrial cancer with novel LIFR inhibitor EC359

Background: Endometrial cancer (EC) is the fourth most common cancer in women. Approximately 80% of EC belong to the endometroid-EC subtype and are driven by estrogen signaling. Advanced-stage EC has limited treatment options with poor prognosis. There is an urgent need for the identification of actionable drivers as new targets for treating advance stage EC. Leukemia inhibitory factor receptor (LIFR) and its ligand LIF plays a major role in cancer progression, metastasis, stemness, and therapy resistance. Published and our preliminary data suggest a critical role of the LIF-LIFR signaling axis in EC progression. The objective of this study is to test the utility of targeting the LIF/LIFR axis using a novel LIFR inhibitor, EC359.

Methods: We used multiple established and primary EC cells to test the utility LIFR inhibitor, EC359 in treating EC. CRISPR/Cas9 system was used to generate LIFR KO EC cells. In vitro activity was tested using Cell-Titer Glo, MTT, invasion, and apoptosis assays. Mechanistic studies were conducted using Western blot, reporter gene assays, and RNA-seq analysis. EC cell-derived xenograft (CDX) and patient-derived explant (PDEX) models were used for preclinical evaluation and toxicity.

Results: EC359 treatment of seven EC cells showed anti-proliferative effects in MTT cell viability assays with an IC50 of 25-100 nM. Further, EC359 treatment reduced invasiveness, stemness, and promoted apoptosis of EC cells. The activity of EC359 is dependent on LIF/LIFR expression in EC cells. CRISPR mediated knockout of LIFR significantly abolished EC359 activity. In vivo xenograft studies using Ishikawa-vector or LIFR-KO cells demonstrated that LIFR-KO significantly reduced EC tumor growth, and tumor weights. Further, EC359 treatment attenuated the activation of LIF/LIFR driven pathways, including STAT3, AKT-mTOR signaling. Mechanistic studies using RNA-seq revealed that EC359 significantly upregulated 213 genes and down regulated 126 genes. Pathway analyses of differential genes revealed enrichment in the apoptotic pathways upon EC359 treatment. EC359 (5mg/kg body weight) treatment significantly reduced CDX tumor progression and reduced proliferation in PDEX models.

Conclusions: Collectively, these data support EC359 as a novel targeted therapy for EC by inhibiting LIF/LIFR oncogenic signaling pathway.

Citation Format: Weiwei Tang, Kumaraguruparan Ramasamy, Sureshkumar M. Pillai, Bindu Santhamma, Swapna Konda, Prabhakar P. Vekata, Logan Blankenship, Junhao Liu, Zexuan Liu, Kristin A. Altwegg, Behnam Ebrahimi, Uday P. Pratap, Xiaonan Li, Edward Kost, Gangadhara R. Sareddy, Ratna K. Vadlamudi, Hareesh B. Nair, Rajeshwar R. Tekmal, Suryavathi Viswanadhapalli. Therapeutic targeting of endometrial cancer with novel LIFR inhibitor EC359 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1253.

Abstract 733: Significance of PELP1/SETDB1 axis in endocrine therapy resistance

BACKGROUND: PELP1 is commonly overexpressed in breast cancer (BCa) and is implicated in endocrine therapy resistance. However, the mechanism by which PELP1 contributes to therapy resistance remains elusive. Our ongoing studies using yeast two hybrid screen identified histone methyltransferase SETDB1 as a novel interactor of PELP1. The objective of this study is to determine the significance of PELP1 interaction with SETDB1 in BCa endocrine therapy resistance.

METHODS: We used two ER+ BCa cell lines (MCF7 and ZR75) and three endocrine therapy resistant cell lines (Tamoxifen resistant MCF7-TamR, Fulvestrant resistant MCF7-FR, Tamoxifen resistant MCF7-PELP1-cyto). Additional BCa models with stable overexpression and under expression of SETDB1 and PELP1 (MCF7-SETDB1-PELP1shRNA, ZR75-SETDB1-PELP1shRNA, ZR75-SETDB1, MCF7-SETDB1, MCF7-TamR-SETDB1shRNA, MCF7-FR-SETDB1shRNA) were generated using lentiviral transduction. Functional significance of cross-talk was tested using MTT, soft agar, and colony formation assays. Mechanistic studies were conducted using immunoprecipitation, Western blotting, and RT-qPCR.

RESULTS: Analyses of TCGA databases showed that SETDB1 expression is positively correlated with PELP1 expression in ER+ BCa (r=0.30, p<0.0001). Immunoprecipitation assays using multiple ER+ BCa cell lysates confirmed the interaction of SETDB1 with PELP1. Using ER+ BCa models with overexpression of SETDB1 or knockdown, we provided evidence that SETDB1 plays an important role in the proliferation of BCa cells. PELP1 knockdown attenuated SETDB1 mediated BCa cells proliferation. SETDB1 upregulation contributed to tamoxifen resistance, while PELP1 knockdown re-sensitized cells to tamoxifen therapy. Further, endocrine therapy resistant model cells (MCF7-TamR, MCF7-FR, MCF7-PELP1-cyto) showed increased expression of SETDB1, and its knockdown sensitized them to endocrine therapy. Mechanistic studies revealed that PELP1 is needed for SETDB1 mediated Akt phosphorylation and activation of its downstream targets such as S6, and Cyclin D1.

CONCLUSIONS: The results of study suggest that the PELP1/SETDB1 interactions contribute to endocrine therapy resistance via aberrant activation of Akt signaling. Targeting PELP1/SETDB1 axis could represent a new therapeutic avenue to mitigate endocrine resistance. Supported by VA grant I01BX004545 (R.K. Vadlamudi)

Citation Format: Zexuan Liu, Junhao Liu, Weiwei Tang, Uday P. Pratap, Kristin A. Altwegg, Behnam Ebrahimi, Xiaonan Li, Gangadhara R. Sareddy, Suryavathi Viswanadhapalli, Ratna K. Vadlamudi. Significance of PELP1/SETDB1 axis in endocrine therapy resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 733.

Abstract PS17-09: Development of a potent mutant-ESR1 targeted agent, ERX-245, for treating metastatic therapy-resistant breast cancer

Background: ESR1 mutations are acquired following ERα targeted therapies and are a major determinant of therapy-resistance. These ESR1 mutations maintain ESR1 signaling, albeit in a ligand-independent manner. Effective drugs targeting these mutant (MT) ERα proteins represent a significant unmet clinical need. We had previously shown that ERX-11, an ESR1-coregulator binding inhibitor, could block the function of these MT ERα proteins. In this study, we sought to leverage recently published structures of MT ERα to develop more potent analogues of ERX-11. Methods: Virtual screening of >250,000 derivatives of ERX-11 was performed with simulated docking on the MT ERα to identify and design analogues of ERX-11. Several hundred analogues were synthesized and tested in vitro using multiple BC model cells that express wild type (WT) ESR1 or mutant (MT) ESR1 (Y537S or D538G). Mechanistic studies were performed using RNA-Seq, Western blotting, qRT-PCR and reporter gene assays. The in vivo efficacy of the most potent ERX-11 analogue ERX-245 was examined using xenograft, PDX and metastatic models of MT-ER driven BC. Results: From our virtual and functional screen, we identified an ERX-11 analogue, ERX-245 as the most potent hit to target MT-ERα. Docking studies modeled a better fit of ERX-245 into the ligand binding domain of both the Y537S and D538G MT-ERα. ERX-245 potently reduced (IC50 ~250 nM) the cell viability of both WT-ERα and MT-ERα driven BC cells but not ERα negative BC cells. ERX-245 significantly reduced the growth (colony formation, clonogenic and mammosphere assays) of MT-ERα BC cells. ERX-245 exhibited synergistic activity in combination with CDK4/6 inhibitors. In distinction to classic SERDs like fulvestrant (which degrade ERα with in 4h), ERX-245 treatment decreased MT-ERα protein levels over 24 hours. PK studies indicated that ERX-245 is more polar and has better solubility and pharmacokinetic properties than ERX-11. ERX-245 reduced tumor growth of subcutaneous xenograft and PDX models driven by MT-ERα as well as the proliferation of xenograft derived MT-ERα explant models. ERX-245 significantly reduced the invasive capability of MT-ERα BC cells in vitro and inhibited both the metastatic capability and growth of metastatic tumors derived from MT-ERα BC cells injected by intracardiac or intratibial routes. Conclusions: Taken together, these results indicate that ERX-245 is a potent and pharmacologically translatable analog of ERX-11, with activity against both primary and metastatic tumors driven by MT-ERα.

Citation Format: Ganesh V Raj, Suryavathi Viswanadhapalli, Karla Parra, Shihong Ma, Tae-Kyung Lee, Xihui Liu, Kara Kassees, Weiwei Tang, Junhao Liu, Zexuan Liu, Uday P Pratap, Behnam Ebrahimi, Rajeshwar Rao Tekmal, Jung-Mo Ann, Ratna K Vadlamudi. Development of a potent mutant-ESR1 targeted agent, ERX-245, for treating metastatic therapy-resistant breast cancer [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS17-09.

Histone deacetylase inhibitors enhance estrogen receptor beta expression and augment agonist-mediated tumor suppression in glioblastoma

BACKGROUND

Glioblastomas (GBMs) are the most lethal primary brain tumors. Estrogen receptor β (ESR2/ERβ) function as a tumor suppressor in GBM, however, ERβ expression is commonly suppressed during glioma progression. In this study, we examined whether drugs that reverse epigenetic modifications will enhance ERβ expression and augment ERβ agonist-mediated tumor suppression.

METHODS

We tested the utility of epigenetic drugs which act as an inhibitor of histone deacetylases (HDACs), histone methylases, and BET enzymes. Mechanistic studies utilized RT-qPCR, chromatin immunoprecipitation (ChIP), and western blotting. Cell viability, apoptosis, colony formation, and invasion were measured using in vitro assays. An orthotopic GBM model was used to test the efficacy of in vivo.

RESULTS

Of all inhibitors tested, HDACi (panobinostat and romidepsin) showed the potential to increase the expression of ERβ in GBM cells. Treatment with HDACi uniquely upregulated ERβ isoform 1 expression that functions as a tumor suppressor but not ERβ isoform 5 that drives oncogenic functions. Further, combination therapy of HDACi with the ERβ agonist, LY500307, potently reduced cell viability, invasion, colony formation, and enhanced apoptosis. Mechanistic studies showed that HDACi induced ERβ is functional, as it enhanced ERβ reporter activities and ERβ target genes expression. ChIP analysis confirmed alterations in the histone acetylation at the ERβ and its target gene promoters. In orthotopic GBM model, combination therapy of panobinostat and LY500307 enhanced survival of tumor-bearing mice.

CONCLUSIONS

Our results suggest that the combination therapy of HDACi and LY500307 provides therapeutic utility in overcoming the suppression of ERβ expression that commonly occurs in GBM progression.

Prevalence and genotyping identification of Cryptosporidium in adult ruminants in central Iran

Background

Apicomplexan parasites of the genus Cryptosporidium infect a wide range of animal species as well as humans. Cryptosporidium spp. can cause life threatening diarrhea especially in young animals, children, immunocompromised patients and malnourished individuals. Asymptomatic cryptosporidial infections in animals can also occur, making these animals potential reservoirs of infection.

Methods

In the present study, a molecular survey of Cryptosporidium spp. in ruminants that were slaughtered for human consumption in Yazd Province, located in central Iran was conducted. Faeces were collected per-rectum from 484 animals including 192 cattle, 192 sheep and 100 goats. DNA was extracted from all samples and screened for Cryptosporidium by PCR amplification of the 18S rRNA gene. Positives were Sanger sequenced and further subtyped by sequence analysis of the 60 kDa glycoprotein (gp60) locus.

Results

In total, Cryptosporidium spp. were detected in 22 animals: C. andersoni and C. bovis in seven and two cattle faecal samples, respectively, C. ubiquitum in five sheep, and C. xiaoi in six sheep and two goat samples, respectively. To our knowledge, this study provides for the first time, molecular information concerning Cryptosporidium species infecting goats in Iran, and is also the first report of C. ubiquitum and C. xiaoi from ruminants in Iran.

Conclusion

The presence of potentially zoonotic species of Cryptosporidium in ruminants in this region may suggest that livestock could potentially contribute to human cryptosporidiosis, in particular among farmers and slaughterhouse workers, in the area. Further molecular studies on local human populations are required to more accurately understand the epidemiology and transmission dynamics of Cryptosporidium spp. in this region.

Molecular typing of Giardia duodenalis in cattle, sheep and goats in an arid area of central Iran

Giardia duodenalis is one of the most common intestinal parasites in humans as well as livestock and wildlife. It is of both public and veterinary health importance in developing nations. A molecular survey of Giardia duodenalis assemblages in ruminants from Yazd Province, Iran was conducted on 484 animal faecal samples collected per rectum from slaughtered ruminants including 192 cattle, 192 sheep and 100 goats from June to November 2017. Species-specific and assemblage-specific PCRs for assemblages A, B and E at the triose phosphate isomerase (tpi) gene were performed, and samples positive for Giardia were confirmed by sequencing. In total, 25 (5.16%) of examined faecal samples including eight cattle (4.2%), twelve sheep (6.2%) and five goats (5%) were infected with G. duodenalis. Assemblage-specific PCR detected G. duodenalis assemblage E in seven faecal samples (six in sheep and one in a goat). Assemblages A and B were not detected. This study provides the first insight into Giardia infection in slaughtered livestock in Iran. Although the prevalence of infection with Giardia in this hot-arid area of Iran was low, educating people about direct contact with livestock such as farmers and abattoirs workers about this zoonotic infection is important.

Cardiac progenitor reprogramming for heart regeneration

Myocardial infarction leads to the loss of a huge number of cardiomyocytes and the reparatory response to this phenomenon is scar tissue formation, which impairs heart function. Direct reprogramming technology offers an alternative strategy for the generation of functional cardiomyocytes not only in vitro, but also in vivo in the site of injury. Results have demonstrated cardiac tissue regeneration and improvement in heart function after myocardial infarction following local injection of vectors encoding reprogramming transcription factors or miRNAs. This shows the great potential of cardiac reprogramming technology for heart regeneration. However, in addition to cardiomyocytes, other cell types, including endothelial cells and smooth muscle cells are also required to be generated in the damaged area in order to achieve complete cardiac tissue regeneration. To this aim induced proliferative/expandable cardiovascular progenitor cells (iCPCs) appear to be an appropriate cell source, which is capable of differentiation into three cardiovascular lineages both in vitro and in vivo. In this regard, this study goes over in vitro and in vivo cardiac reprogramming technology and specifically deals with cardiac progenitor reprogramming and its potential for heart regeneration.

In vivo reprogramming for heart regeneration: A glance at efficiency, environmental impacts, challenges and future directions

Replacing dying or diseased cells of a tissue with new ones that are converted from patient's own cells is an attractive strategy in regenerative medicine. In vivo reprogramming is a novel strategy that can circumvent the hurdles of autologous/allogeneic cell injection therapies. Interestingly, studies have demonstrated that direct injection of cardiac transcription factors or specific miRNAs into the infarct border zone of murine hearts following myocardial infarction converts resident cardiac fibroblasts into functional cardiomyocytes. Moreover, in vivo cardiac reprogramming not only drives cardiac tissue regeneration, but also improves cardiac function and survival rate after myocardial infarction. Thanks to the influence of cardiac microenvironment and the same developmental origin, cardiac fibroblasts seem to be more amenable to reprogramming toward cardiomyocyte fate than other cell sources (e.g. skin fibroblasts). Thus, reprogramming of cardiac fibroblasts to functional induced cardiomyocytes in the cardiac environment holds great promises for induced regeneration and potential clinical purposes. Application of small molecules in future studies may represent a major advancement in this arena and pharmacological reprogramming would convey reprogramming technology to the translational medicine paradigm. This study reviews accomplishments in the field of in vitro and in vivo mouse cardiac reprogramming and then deals with strategies for the enhancement of the efficiency and quality of the process. Furthermore, it discusses challenges ahead and provides suggestions for future research. Human cardiac reprogramming is also addressed as a foundation for possible application of in vivo cardiac reprogramming for human heart regeneration in the future.

Chemicals as the Sole Transformers of Cell Fate

Forced expression of lineage-specific transcription factors in somatic cells can result in the generation of different cell types in a process named direct reprogramming, bypassing the pluripotent state. However, the introduction of transgenes limits the therapeutic applications of the produced cells. Numerous small-molecules have been introduced in the field of stem cell biology capable of governing self-renewal, reprogramming, transdifferentiation and regeneration. These chemical compounds are versatile tools for cell fate conversion toward desired outcomes. Cell fate conversion using small-molecules alone (chemical reprogramming) has superiority over arduous traditional genetic techniques in several aspects. For instance, rapid, transient, and reversible effects in activation and inhibition of functions of specific proteins are of the profits of small-molecules. They are cost-effective, have a long half-life, diversity on structure and function, and allow for temporal and flexible regulation of signaling pathways. Additionally, their effects could be adjusted by fine-tuning concentrations and combinations of different small-molecules. Therefore, chemicals are powerful tools in cell fate conversion and study of stem cell and chemical biology in vitro and in vivo. Moreover, transgene-free and chemical-only transdifferentiation approaches provide alternative strategies for the generation of various cell types, disease modeling, drug screening, and regenerative medicine. The current review gives an overview of the recent findings concerning transdifferentiation by only small-molecules without the use of transgenes.

Biological computational approaches: new hopes to improve (re)programming robustness, regenerative medicine and cancer therapeutics

Hundreds of transcription factors (TFs) are expressed and work in each cell type, but the identity of the cells is defined and maintained through the activity of a small number of core TFs. Existing reprogramming strategies predominantly focus on the ectopic expression of core TFs of an intended fate in a given cell type regardless of the state of native/somatic gene regulatory networks (GRNs) of the starting cells. Interestingly, an important point is that how much products of the reprogramming, transdifferentiation and differentiation (programming) are identical to their in vivo counterparts. There is evidence that shows that direct fate conversions of somatic cells are not complete, with target cell identity not fully achieved. Manipulation of core TFs provides a powerful tool for engineering cell fate in terms of extinguishment of native GRNs, the establishment of a new GRN, and preventing installation of aberrant GRNs. Conventionally, core TFs are selected to convert one cell type into another mostly based on literature and the experimental identification of genes that are differentially expressed in one cell type compared to the specific cell types. Currently, there is not a universal standard strategy for identifying candidate core TFs. Remarkably, several biological computational platforms are developed, which are capable of evaluating the fidelity of reprogramming methods and refining existing protocols. The current review discusses some deficiencies of reprogramming technologies in the production of a pure population of authentic target cells. Furthermore, it reviews the role of computational approaches (e.g. CellNet, KeyGenes, Mogrify, etc.) in improving (re)programming methods and consequently in regenerative medicine and cancer therapeutics.

Reprogramming barriers and enhancers: strategies to enhance the efficiency and kinetics of induced pluripotency

Induced pluripotent stem cells are powerful tools for disease modeling, drug screening, and cell transplantation therapies. These cells can be generated directly from somatic cells by ectopic expression of defined factors through a reprogramming process. However, pluripotent reprogramming is an inefficient process because of various defined and unidentified barriers. Recent studies dissecting the molecular mechanisms of reprogramming have methodically improved the quality, ease, and efficiency of reprogramming. Different strategies have been applied for enhancing reprogramming efficiency, including depletion/inhibition of barriers (p53, p21, p57, p16(Ink4a)/p19(Arf), Mbd3, etc.), overexpression of enhancing genes (e.g., FOXH1, C/EBP alpha, UTF1, and GLIS1), and administration of certain cytokines and small molecules. The current review provides an in-depth overview of the cutting-edge findings regarding distinct barriers of reprogramming to pluripotency and strategies to enhance reprogramming efficiency. By incorporating the mechanistic insights from these recent findings, a combined method of inhibition of roadblocks and application of enhancing factors may yield the most reliable and effective approach in pluripotent reprogramming.

A low-cost mesocosm for the study of behaviour and reproductive potential in Afrotropical mosquito (Diptera: Culicidae) vectors of malaria

A large-scale mesocosm was constructed and tested for its effectiveness for use in experiments on behaviour, reproduction and adult survivorship in the Afrotropical malaria vector Anopheles gambiae s.s. Giles (Diptera: Culicidae) in temperate climates. The large space (82.69 m(3) ) allowed for semi-natural experiments that increased demand on a mosquito's energetic reserves in an environment of widely distributed resources. A one-piece prefabricated enclosure, made with white netting and vinyl, prevented the ingress of predators and the egress of mosquitoes. Daylight and white materials prompted the mosquitoes to seclude themselves in restricted daytime resting sites and allowed the easy collection of dead bodies so that daily mortality could be assessed accurately using a method that accounts for the loss of a proportion of bodies. Here, daily, age-dependent mortality rates of males and females were estimated using Bayesian Markov chain Monte Carlo simulation. In overnight experiments, mosquitoes successfully located plants and took sugar meals. A 3-week survival trial with a single cohort demonstrated successful mating, blood feeding, oviposition and long life. The relatively low cost of the mesocosm and the performance of the mosquitoes in it make it a viable option for any behavioural or ecological study of tropical mosquitoes in which space and seasonal cold are constraining factors.

A modified efficient method for dental pulp stem cell isolation

BACKGROUND

Dental pulp stem cells can be used in regenerative endodontic therapy. The aim of this study was to introduce an efficient method for dental pulp stem cells isolation.

MATERIALS AND METHODS

In this in-vitro study, 60 extracted human third molars were split and pulp tissue was extracted. Dental pulp stem cells were isolated by the following three different methods: (1) digestion of pulp by collagenase/dispase enzyme and culture of the released cells; (2) outgrowth of the cells by culture of undigested pulp pieces; (3) digestion of pulp tissue pieces and fixing them. The cells were cultured in minimum essential medium alpha modification (αMEM) medium supplemented with 20% fetal bovine serum(FBS) in humid 37°C incubator with 5% CO 2. The markers of stem cells were studied by reverse transcriptase polymerase chain reaction (PCR). The student t-test was used for comparing the means of independent groups. P <0.05 was considered as significant.

RESULTS

The results indicated that by the first method a few cell colonies with homogenous morphology were detectable after 4 days, while in the outgrowth method more time was needed (10-12 days) to allow sufficient numbers of heterogeneous phenotype stem cells to migrate out of tissue. Interestingly, with the improved third method, we obtained stem cells successfully with about 60% efficiency after 2 days. The results of RT-PCR suggested the expression of Nanog, Oct-4, and Nucleostemin markers in the isolated cells from dental pulps.

CONCLUSION

This study proposes a new method with high efficacy to obtain dental pulp stem cells in a short time.

Effect of cysteine and glutamine added to extender on post-thaw sperm functional parameters of buffalo bull

Amino acids seem to be crucial components for semen freezing extender due to antioxidant properties. Therefore, this study aimed to assess motility parameters, membrane integrity, intracellular reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and DNA damage to detect the optimum concentrations of cysteine and glutamine for buffalo semen cryopreservation. Twenty ejaculates of four buffalo bulls were diluted in tris-egg yolk extender and divided into seven equal groups consisting of cysteine (5, 7.5 and 10 mmol), glutamine (10, 15 and 20 mmol) and no additive. Supplementation of 5 and 7.5 mmol cysteine and 15 mmol glutamine in cryopreservation extender significantly increased post-thaw motility and plasma membrane integrity of spermatozoa with significant reduction in intracellular ROS when compared with control groups (P < 0.05). Cysteine at 7.5 mmol concentration elevated progressive motility and MMP, compared with control (P < 0.05). No significant differences were observed for motion patterns and DNA damage of frozen-thawed buffalo spermatozoa in extender containing amino acids. The findings of this study showed that supplementation of 7.5 mmol cysteine and 15 mmol glutamine in semen cryopreservation extender has more potential to decrease intracellular ROS, and subsequently elevate motility and membrane integrity of buffalo frozen-thawed spermatozoa.

Most human metapneumovirus and human respiratory syncytial virus in infant nasal secretions is cell free

BACKGROUND

Nasopharyngeal secretions aspirated from infants with bronchiolitis (NPA) are a valuable resource for the study of virus dynamics and local inflammatory responses, however samples are small and difficult to manipulate.

OBJECTIVES

To improve yield of NPA from infants. To establish if removal of the cellular component of NPA affects quantification of human metapneumovirus (hMPV) or human respiratory syncytial virus (hRSV) genome.

STUDY DESIGN

Weight of NPA collected into traps from 30 infants was compared with that collected in trap plus catheter and washed through with saline from another 30 infants. hMPV (n=33) and hRSV (n=30) genome was measured by reverse-transcribed real-time polymerase chain reaction (RT-RT-PCR) in paired whole and cell-free NPA collected by the improved method.

RESULTS

The improved method of NPA collection gave near two-fold greater weight (p = 0.002) of NPA (mean = 0.52 g (S.D. = 0.30 g)) than the traditional method (0.32 g (S.D. 0.19)). There was strong agreement and no significant difference between viral load measured in whole and cell-free fractions of NPA for both viruses (samples (n), correlation coefficient (cc) and significance (p)); hMPV (n=33, cc=0.938, p<0.001) and hRSV (n=30, cc=0.977 and p<0.001).

CONCLUSIONS

The majority of hRSV and hMPV in nasal secretions is not associated with cells. Removal of the cellular component of NPA does not interfere with quantification of hRSV and hMPV.

A phase 1 study of daily oral perifosine (P) and weekly gemcitabine (G)

13084

Background: Miltefosine (M) has been shown to be synergistic with gemcitabine (G) in vitro (Georgieva Cancer Letters 182: 163–174, 2002). Perifosine (P) is a derivative of M with less GI toxicity. Methods: Twenty-two patients (pts) were enrolled on a phase 1 study to determine if G could be given at a dose of 1000 mg/m2 on days 1 and 8 of a 21-day cycle with 50 mg of P given orally 1, 2 or 3 times a day on days 1–14. Three pts were entered at each dose and the cohort expanded to 6 if 2 or more experienced a grade 3/4 non-hematologic toxicity (DLT) during the first cycle. A dose was toxic if 4 or more pts experienced a DLT during cycle 1. Ten additional pts were entered at the highest dose achieved. Results: Disease sites: lung 6, pancreas 3, breast 3, renal 2, sarcoma 2, other 5. The median age was 61 (range 29–82); 11 pts were male and median ECOG performance status was 1 (range 0–2). All pts had received prior chemotherapy (median 3, range 1–4) & 6 had received prior G. 10 pts had received prior radiotherapy. The grade 3/4 non hematologic toxicities for each cohort are given in the table below: One pt on cohort 3 died from pneumonia and sepsis unrelated to therapy after cycle 1. A median of 4 cycles (range 1 - 18) were delivered. At each dose 50% of pts had no G dose reductions. P doses were reduced in 7% of cycles (50 mg - 5%, 100 mg - 15%, 150 mg - 7%). Fifteen pts were evaluable & 4 partial responses (lung, breast, pancreas and unknown primary) were seen; 6 pts had stable disease (renal (2), sarcoma (2), liver and head/neck) for a median of 6 (range 3 - 9) months. No responder had received prior G. Pharmacokinetic (PK) studies showed that the steady state level at 150 mg was 9.47 ± 4.56 μM compared to 10.14 ± 2.02 μM in an earlier study (Crul, Eur. J. Cancer 38: 1615–21, 2002) when this dose of perifosine was used alone. Conclusions: It is concluded that full dose G can be safely administered with perifosine doses up to 150 mg with manageable toxicity and without affecting the PK of P. Phase II studies are warranted to further define the activity of the combination and the contribution of P.

[Table: see text]

[Table: see text]

Aromatase inhibitor (AI)-associated arthralgia (A) and bone pain (BP): Frequency and characterization in clinical practice

6137

Background: Prior studies of AI have identified A and/or BP as side effects. Reported incidences have varied from 4% (IMPACT) to 35.6% (ATAC). In order to determine the frequency of A or BP in clinical practice, we reviewed a consecutive series of patients (PTs) receiving AI in community cancer centers. Methods: The charts of consecutive PTs receiving AI were reviewed, and PTs were interviewed regarding the occurrence of A or BP (ABP), severity, whether ABP was worse than before AI therapy, preexisting co-morbidities, type of therapy for ABP, and pain characterization. Results: 56 PTs were receiving AI. The type of AI used was anastrazole in 44 PTs, letrozole in 10 PTs, and exemestane in 2 PTs. The age range was 45 to 89 years. All PTs had breast cancer. The duration AI usage was 1 to 44 mo. Worsening of ABP compared to pretreatment ABP was reported in 34 PTs (61%). In 11 Pts (20%), severity was sufficient and control poor enough to result in discontinuation of AI at a median of 2 mo of AI therapy. The median severity of ABP, when present, was 7.5 on a 10 point pain scale. The character of the ABP was continuous in 20 (59%) and intermittent in 14 (41%), affected central/axial bones in 20 (36%), and peripheral bones in 35 (64%). Coexisting conditions possibly contributing to worsening of ABP occurred in 36%, consisting of degenerative joint disease 10, fibromyalgia 1, osteoporosis 4, and degenerative disc disease 1. Therapy associated with amelioration of symptoms included acetaminophen in 26%, NSAIDs in 45%, mild opiates in 11%, strong opiates in 5%, and glucosamine in 13%. The occurrence of ABP was not associated with age (68% in PTs less than 60 versus 57% in PTs over 60). The occurrence of ABP was not associated with duration of use of AI (50% of 16 Pts on AI for 3–6 mo, 75% for 7–12 mo, and 56% for over 12 mo). Conclusions: The occurrence of AI associated ABP is higher in a non-clinical trial population of PTs than reported in most clinical trials. This side effect is severe enough to cause discontinuation of needed AI therapy in 20%. Further studies are warranted to determine the mechanism of AI associated ABP, and optimal therapy. It is reasonable to consider glucosamine as well as standard analgesics in controlling this syndrome.

No significant financial relationships to disclose.

Perifosine (P) can be combined with docetaxel (T) without dose reduction of either drug

13066

Background: Perifosine is an alkylphospholipid that modulates several signal transduction pathways, including Akt, which is often activated in taxane resistant tumors and is thought to be one mediator of such resistance. The combination of T, 75 mg/m2 every 3 weeks, and prednisone (Pr), 5 mg bid has become standard therapy for patients (pts) with metastatic prostate cancer. The addition of P might decrease resistance to T in these patients who often have activated Akt because of PTEN mutations. This phase I trial is the first attempt to combine these agents. Methods: Between 12/04 and 9/05, 39 pts were enrolled. P was given either daily as a 50 mg tablet 1, 2 or 3 times per day on days 1–14 or weekly in doses of 300 mg every 4 - 6 hours 3, 4 or 5 times on days 1–2, 8–9 and 15–16 of each 21 day cycle. T, 75 mg/m2, was given on day 8 of a 21 day cycle with or without Pr. Results: Disease sites: prostate 11, NSCLC 9, ovary 4, head/neck 3, pancreas 3, breast 2 & other 7. Median age was 63 (range 37–80); 24 patients were male and median ECOG performance status was 1 (range 0–2). 34 pts had received prior chemotherapy including 24 previously given a taxane. Three patients were entered at each dose level for each schedule and the cohort expanded to 6 patients if 2 or more patients experienced a grade 3/4 non-hematologic toxicity (DLT) during the first cycle of therapy. A dose level was toxic if 4 or more patients experienced a DLT during cycle 1. The grade 3/4 toxicities for each perifosine dosing schedule are given in the table . Glucose values for the grade 3 toxicities were between 253 and 306. This was seen only in the Pr pts & has not been observed in other P trials. P dose reductions were required in 4% of cycles for daily P, 5% for daily P+Pr and 37% for weekly P. Conclusions: Daily doses up to 150 mg could be administered either with or without Pr but the maximum tolerated dose for the weekly regimen was 1200 mg It is concluded that daily P ± Pr is well tolerated with T 75 mg/m2 q 3 weeks and that daily doses are preferred for phase II studies to further define activity of the combination.

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[Table: see text]

A phase 1 study of daily oral perifosine (P) with weekly paclitaxel (T)

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Background: P is an oral signal transduction modulator with limited toxicity. P combined with 3-weekly T led to no toxicity beyond that expected with each drug alone. Weekly T is more effective than 3-weekly T in some settings (Seidman, ASCO 2004:512), so this study evaluated whether weekly T altered the tolerance to P. Methods: Twelve patients (pts) were enrolled. T was given at 80 mg/m2 on days 1, 8 and 15 of a 28 day cycle. P, 50 mg, was given 1, 2 or 3 times a day on days 1–21 of each cycle. Results: Tumor types were lung 2, breast 4, endometrium 3 and other 3. Median age was 55 (range 41–82). All pts had received prior chemotherapy (median 2.5, range 1–3 regimens) and 6 a prior taxane. Three pts were entered at each dose and the cohort expanded to 6 pts if 2 or more experienced a grade 3/4 non-hematologic toxicity (DLT) during cycle 1. A dose was toxic if 4 or more pts experienced a DLT during cycle 1. Since toxicity was not dose limiting in any cohort, the 150 dose was expanded to 6 pts. There were no grade 3/4 hematologic toxicities. The grade 3/4 non-hematologic toxicities at least possibly related to perifosine are given in the table below: The high glucose values were 276 and 277. A total of 38 cycles and a median of 2.5 cycles per pt (range 1–10+) were delivered. Full dose T was given in 85% of cycles (50 mg–100%, 100 mg–85%, 150 mg–86%). Dose reductions of T in 3 pts were related to neuropathy, suspected bronchitis and fatigue. One pt treated at 100 mg requested T be stopped after 6 cycles due to neurotoxicity and has received 6 additional cycles of perifosine alone. Perifosine dose reductions were required in 13% of cycles (50 mg - 0%, 100 mg - 21%, 150 mg - 9%). One pt each was reduced due to constipation, nausea and diarrhea. Five of 7 evaluable pts had stable disease (breast 2, cervix, endometrium, thyroid) for at least 3 months. Four remain stable at 3+ to 10+ months. Conclusions: The single agent doses of P (150 mg daily) & T (80 mg/m2 weekly) were given without increasing the toxicities expected from using each drug alone. Phase II studies are warranted to define the activity of the combination.

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[Table: see text]