Molecular evidence for increased antitumor activity of gemcitabine in combination with a cyclin-dependent kinase inhibitor, P276-00 in pancreatic cancers

Rathos, Maggie J.; Joshi, Kavita; Khanwalkar, Harshal; Manohar, Sonal M; Joshi, Kalpana

doi:10.1186/1479-5876-10-161

Cited by 32 publications

(29 citation statements)

References 27 publications

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“…Several reports documenting gemcitabine sensitivity of PDA cell lines show higher induction of apoptosis following chemotherapeutic treatment than prior to treatment, but these studies involve cells treated for 48 to 72 h and seeded at densities ranging from 5 to 15 times lower than in the present study (77)(78)(79). As our study was concerned with the ability of influenza virus to induce apoptosis following infection at a high MOI, we chose to study the response over a period of 24 h, starting with those of confluent monolayers, to monitor CPE following infection.…”

Section: Discussionmentioning

confidence: 50%

Oncolytic Activity of Avian Influenza Virus in Human Pancreatic Ductal Adenocarcinoma Cell Lines

Kasloff

Pizzuto

Silic-Benussi

et al. 2014

J Virol

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Pancreatic ductal adenocarcinoma (PDA) is the most lethal form of human cancer, with dismal survival rates due to late-stage diagnoses and a lack of efficacious therapies. Building on the observation that avian influenza A viruses (IAVs) have a tropism for the pancreas in vivo, the present study was aimed at testing the efficacy of IAVs as oncolytic agents for killing human PDA cell lines. Receptor characterization confirmed that human PDA cell lines express the alpha-2,3-and the alpha-2,6-linked glycan receptor for avian and human IAVs, respectively. PDA cell lines were sensitive to infection by human and avian IAV isolates, which is consistent with this finding. Growth kinetic experiments showed preferential virus replication in PDA cells over that in a nontransformed pancreatic ductal cell line. Finally, at early time points posttreatment, infection with IAVs caused higher levels of apoptosis in PDA cells than gemcitabine and cisplatin, which are the cornerstone of current therapies for PDA. In the BxPC-3 PDA cell line, apoptosis resulted from the engagement of the intrinsic mitochondrial pathway. Importantly, IAVs did not induce apoptosis in nontransformed pancreatic ductal HPDE6 cells. Using a model based on the growth of a PDA cell line as a xenograft in SCID mice, we also show that a slightly pathogenic avian IAV significantly inhibited tumor growth following intratumoral injection. Taken together, these results are the first to suggest that IAVs may hold promise as future agents of oncolytic virotherapy against pancreatic ductal adenocarcinomas. IMPORTANCEDespite intensive studies aimed at designing new therapeutic approaches, PDA still retains the most dismal prognosis among human cancers. In the present study, we provide the first evidence indicating that avian IAVs of low pathogenicity display a tropism for human PDA cells, resulting in viral RNA replication and a potent induction of apoptosis in vitro and antitumor effects in vivo. These results suggest that slightly pathogenic IAVs may prove to be effective for oncolytic virotherapy of PDA and provide grounds for further studies to develop specific and targeted viruses, with the aim of testing their efficacy in clinical contexts.

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Section: Discussionmentioning

confidence: 50%

Oncolytic Activity of Avian Influenza Virus in Human Pancreatic Ductal Adenocarcinoma Cell Lines

Kasloff

Pizzuto

Silic-Benussi

et al. 2014

J Virol

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“…8 Others have demonstrated similar potentiating activity of P276-00 in combination with doxorubicin in non-small cell lung carcinoma cell lines and xenografts as well as with gemcitabine in pancreas cancer xenografts. 16-18 In fact, the latter of these strategies was being investigated in a phase I/II clinical trial in patients with advanced pancreatic cancer, in which P276-00 was well-tolerated in these patients when administered with gemcitabine with mild trends of efficacy. 19 Others have shown potential deleterious effects of combining DNA-damaging agents with a CDK4/6 inhibitor (PD0332991; Pfizer, Inc.) in a mouse xenograft model of breast cancer.…”

Section: Discussionmentioning

confidence: 99%

A Phase II, Single-Arm, Open-Label, Multicenter Study to Evaluate the Efficacy and Safety of P276-00, a Cyclin-Dependent Kinase Inhibitor, in Patients With Relapsed or Refractory Mantle Cell Lymphoma

Cassaday

Goy

Advani

et al. 2015

Clinical Lymphoma Myeloma and Leukemia

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Overexpression of cyclin D1 is a hallmark feature of mantle cell lymphoma (MCL). Many of the oncogenic effects of cyclin D1 are mediated through cyclin dependent kinases (CDKs). P276-00 is a potent small-molecule inhibitor of CDK4-D1, CDK1-B, and CDK9-T with promising activity in pre-clinical models. In Phase I studies of P276-00 in patients with refractory solid neoplasms, it was well-tolerated with a mild trend of single-agent efficacy. A Phase II study of this agent was conducted in patients with relapsed or refractory MCL at the recommended dose of 185 mg/m2/day from days 1-5 of a 21-day cycle. Thirteen patients were enrolled on this study: 11 patients had disease progression, 1 patient was withdrawn due to an adverse event (AE), and 1 patient died. Eleven patients (84.6%) experienced a treatment-emergent AE deemed related to P276-00. Nine patients (69.2%) received at least 2 cycles of treatment, which was the pre-defined threshold to be evaluable for efficacy; treatment was discontinued early in 2 patients due to AEs (one of which was attributed to P276-00 administration) and in 2 patients due to disease progression. Two patients experienced stable disease for an estimated median duration of 60.5 days (range 58-63 days). The estimated median time to progression for the pre-defined efficacy population was 43 days (range 38-58 days). Given the results observed in this study, if continued evaluation of CDK inhibition in MCL occurs, it should be considered earlier in the disease course or as part of combination strategies for relapsed or refractory disease.

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“…SMAD3 is a CDK4 substrate, and CDK4 phosphorylation of SMAD3 in the linker region inhibits the transcriptional activity and tumor suppressive function of TGF-␤ signaling (11). There are currently several clinical trials ongoing with CDK4 inhibitors in combinatorial cancer treatment together with standard cytotoxic drugs (24). Among other effects on the cell cycle, these compounds may also contribute to reducing the levels of linker-phosphorylated SMADs in tumors.…”

Section: Cdk4 Inhibitors Reduce Levels Of P179smad3-mentioning

confidence: 99%

Single Chain Antibodies as Tools to Study transforming growth factor-β-Regulated SMAD Proteins in Proximity Ligation-Based Pharmacological Screens

Blokzijl

Zięba

Hust

et al. 2016

Molecular & Cellular Proteomics

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The cellular heterogeneity seen in tumors, with subpopulations of cells capable of resisting different treatments, renders single-treatment regimens generally ineffective. Accordingly, there is a great need to increase the repertoire of drug treatments from which combinations may be selected to efficiently target sets of pathological processes, while suppressing the emergence of resistance mutations. In this regard, members of the TGF-␤ signaling pathway may furnish new, valuable therapeutic targets. In the present work, we developed in situ proximity ligation assays (isPLA) to monitor the state of the TGF-␤ signaling pathway. Moreover, we extended the range of suitable affinity reagents for this analysis by developing a set of in-vitro-derived human antibody fragments (single chain fragment variable, scFv) that bind SMAD2 (Mothers against decapentaplegic 2), 3, 4, and 7 using phage display. These four proteins are all intracellular mediators of TGF-␤ signaling. We also developed an scFv specific for SMAD3 phosphorylated in the linker domain 3 (p179 SMAD3). This phosphorylation has been shown to inactivate the tumor suppressor function of SMAD3. The single chain affinity reagents developed in the study were fused tocrystallizable antibody fragments (Fc-portions) and expressed as dimeric IgG-like molecules having Fc domains (Yumabs), and we show that they represent valuable reagents for isPLA.Using these novel assays, we demonstrate that p179 SMAD3 forms a complex with SMAD4 at increased frequency during division and that pharmacological inhibition of cyclin-dependent kinase 4 (CDK4) 1 reduces the levels of p179SMAD3 in tumor cells. We further show that the p179SMAD3-SMAD4 complex is bound for degradation by the proteasome. Finally, we developed a chemical screening strategy for compounds that reduce the levels of p179SMAD3 in tumor cells with isPLA as a read-out, using the p179SMAD3 scFv SH544-IIC4. The screen identified two kinase inhibitors, known inhibitors of the insulin receptor, which decreased levels of p179SMAD3/SMAD4 complexes, thereby demonstrating the suitability of the recombinant affinity reagents applied in isPLA in screening for inhibitors of cell signaling. Molecular & Cellular

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Molecular evidence for increased antitumor activity of gemcitabine in combination with a cyclin-dependent kinase inhibitor, P276-00 in pancreatic cancers

Cited by 32 publications

References 27 publications

Oncolytic Activity of Avian Influenza Virus in Human Pancreatic Ductal Adenocarcinoma Cell Lines

Oncolytic Activity of Avian Influenza Virus in Human Pancreatic Ductal Adenocarcinoma Cell Lines

A Phase II, Single-Arm, Open-Label, Multicenter Study to Evaluate the Efficacy and Safety of P276-00, a Cyclin-Dependent Kinase Inhibitor, in Patients With Relapsed or Refractory Mantle Cell Lymphoma

Single Chain Antibodies as Tools to Study transforming growth factor-β-Regulated SMAD Proteins in Proximity Ligation-Based Pharmacological Screens

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