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Image based detection and targeting of therapy resistance in pancreatic adenocarcinoma

View Article: PubMed Central - PubMed

ABSTRACT

Pancreatic intraepithelial neoplasia (PanIN) is a premalignant lesion that can progress to pancreatic ductal adenocarcinoma, a highly lethal malignancy marked by its late stage at clinical presentation and profound drug resistance1. The genomic alterations that commonly occur in pancreatic cancer include activation of KRAS2 and inactivation of p53, and SMAD42-4. To date, however, it has been challenging to target these pathways therapeutically; thus the search for other key mediators of pancreatic cancer growth remains an important endeavor. Here we show that the stem cell determinant Musashi (Msi) is a critical element of pancreatic cancer progression in both genetic models and patient derived xenografts. Specifically, we developed Msi reporter mice that allowed image based tracking of stem cell signals within cancers, revealing that Msi expression rises as PanIN progresses to adenocarcinoma, and that Msi-expressing cells are key drivers of pancreatic cancer: they preferentially harbor the capacity to propagate adenocarcinoma, are enriched in circulating tumor cells, and are markedly drug resistant. This population could be effectively targeted by deletion of either Msi1 or Msi2, which led to a striking defect in PanIN progression to adenocarcinoma and an improvement in overall survival. Msi inhibition also blocked the growth of primary patient-derived tumors, suggesting that this signal is required for human disease. To define the translational potential of this work we developed antisense oligonucleotides against Msi; these showed reliable tumor penetration, uptake and target inhibition, and effectively blocked pancreatic cancer growth. Collectively, these studies highlight Msi reporters as a unique tool to identify therapy resistance, and define Msi signaling as a central regulator of pancreatic cancer.

No MeSH data available.


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Loss of Msi1 or Msi2 impairs tumor initiation and progression in a genetic mouse model of pancreatic cancer(a) Coronal and sagittal MRI images of normal, WT-KPf/fC and Msi1−/−-KPf/fC mice with 3-dimensional volume rendering of tumor mass (red). (b) Average volumes of isolated WT-KPf/fC (n=13) and Msi1−/−-KPf/fC tumors (n=9). (c-d) Histology and (e-f) quantification of PanIN and/or adenocarcinoma areas in WT-KPf/fC and Msi1−/−-KPf/fC tumors. (g) Survival of mice orthotopically grafted with Msi1−/−-KPf/fC or WTKPf/fC tumors (n=16). Analysis of Msi2−/−-KPf/fC tumors (h) by MRI and (i) after isolation, WT-KPf/fC (n=5), Msi2−/−-KPf/fC (n=7). (j-m) Histology of WT-KPf/fC and Msi2−/−-KPf/fC pancreatic tumors (40x magnification); (k) Adenocarcinoma, liver invasion (green arrows), (l) adenocarcinoma (yellow arrows), (m) PanINs (blue arrows). (n-o) quantification of PanIN and/or adenocarcinoma areas in WT-KPf/fC and Msi2−/−-KPf/fC tumors (n=6). (p) Survival of autochthonous Msi2−/−-KPf/fC (n=19) or WT-KPf/fC (n=32) mice. Log-rank (Mantel-Cox) survival analysis (p<0.0001). Data represented as mean ± SEM. ** P < 0.01, *** P < 0.001 by Student's t-test. Source Data for all panels are available online.
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Figure 2: Loss of Msi1 or Msi2 impairs tumor initiation and progression in a genetic mouse model of pancreatic cancer(a) Coronal and sagittal MRI images of normal, WT-KPf/fC and Msi1−/−-KPf/fC mice with 3-dimensional volume rendering of tumor mass (red). (b) Average volumes of isolated WT-KPf/fC (n=13) and Msi1−/−-KPf/fC tumors (n=9). (c-d) Histology and (e-f) quantification of PanIN and/or adenocarcinoma areas in WT-KPf/fC and Msi1−/−-KPf/fC tumors. (g) Survival of mice orthotopically grafted with Msi1−/−-KPf/fC or WTKPf/fC tumors (n=16). Analysis of Msi2−/−-KPf/fC tumors (h) by MRI and (i) after isolation, WT-KPf/fC (n=5), Msi2−/−-KPf/fC (n=7). (j-m) Histology of WT-KPf/fC and Msi2−/−-KPf/fC pancreatic tumors (40x magnification); (k) Adenocarcinoma, liver invasion (green arrows), (l) adenocarcinoma (yellow arrows), (m) PanINs (blue arrows). (n-o) quantification of PanIN and/or adenocarcinoma areas in WT-KPf/fC and Msi2−/−-KPf/fC tumors (n=6). (p) Survival of autochthonous Msi2−/−-KPf/fC (n=19) or WT-KPf/fC (n=32) mice. Log-rank (Mantel-Cox) survival analysis (p<0.0001). Data represented as mean ± SEM. ** P < 0.01, *** P < 0.001 by Student's t-test. Source Data for all panels are available online.

Mentions: Because Msi expression rose during progression (Extended Data Fig. 1f-k, 4a), and marked therapy resistant cells, we tested if genetic or pharmacologic targeting of Msi could eradicate this ‘high risk’ population. Deletion of Msi1 led to a 5-fold reduction in tumor volume by MRI (Fig. 2a-b, Extended Data Fig. 4b, Supplementary Videos S2-S4). Histologically, adenocarcinoma areas comprised 67% of WT-KPf/fC but less than 10% of Msi1−/−KPf/fC pancreata; further while Msi1 loss allowed low grade PanINs to form, it largely blocked progression to adenocarcinoma (Fig. 2c-f, Extended Data Fig. 4 c, d). Finally, Msi1 deletion improved survival in orthotopic grafts: median survival for WT-KPf/fC graft recipients was 28.5 days, and for Msi1−/−-KPf/fC grafts was 70.5 days, representing a 2.5-fold increase in survival time and a 23-fold decrease in risk of death (Fig. 2g).


Image based detection and targeting of therapy resistance in pancreatic adenocarcinoma
Loss of Msi1 or Msi2 impairs tumor initiation and progression in a genetic mouse model of pancreatic cancer(a) Coronal and sagittal MRI images of normal, WT-KPf/fC and Msi1−/−-KPf/fC mice with 3-dimensional volume rendering of tumor mass (red). (b) Average volumes of isolated WT-KPf/fC (n=13) and Msi1−/−-KPf/fC tumors (n=9). (c-d) Histology and (e-f) quantification of PanIN and/or adenocarcinoma areas in WT-KPf/fC and Msi1−/−-KPf/fC tumors. (g) Survival of mice orthotopically grafted with Msi1−/−-KPf/fC or WTKPf/fC tumors (n=16). Analysis of Msi2−/−-KPf/fC tumors (h) by MRI and (i) after isolation, WT-KPf/fC (n=5), Msi2−/−-KPf/fC (n=7). (j-m) Histology of WT-KPf/fC and Msi2−/−-KPf/fC pancreatic tumors (40x magnification); (k) Adenocarcinoma, liver invasion (green arrows), (l) adenocarcinoma (yellow arrows), (m) PanINs (blue arrows). (n-o) quantification of PanIN and/or adenocarcinoma areas in WT-KPf/fC and Msi2−/−-KPf/fC tumors (n=6). (p) Survival of autochthonous Msi2−/−-KPf/fC (n=19) or WT-KPf/fC (n=32) mice. Log-rank (Mantel-Cox) survival analysis (p<0.0001). Data represented as mean ± SEM. ** P < 0.01, *** P < 0.001 by Student's t-test. Source Data for all panels are available online.
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Figure 2: Loss of Msi1 or Msi2 impairs tumor initiation and progression in a genetic mouse model of pancreatic cancer(a) Coronal and sagittal MRI images of normal, WT-KPf/fC and Msi1−/−-KPf/fC mice with 3-dimensional volume rendering of tumor mass (red). (b) Average volumes of isolated WT-KPf/fC (n=13) and Msi1−/−-KPf/fC tumors (n=9). (c-d) Histology and (e-f) quantification of PanIN and/or adenocarcinoma areas in WT-KPf/fC and Msi1−/−-KPf/fC tumors. (g) Survival of mice orthotopically grafted with Msi1−/−-KPf/fC or WTKPf/fC tumors (n=16). Analysis of Msi2−/−-KPf/fC tumors (h) by MRI and (i) after isolation, WT-KPf/fC (n=5), Msi2−/−-KPf/fC (n=7). (j-m) Histology of WT-KPf/fC and Msi2−/−-KPf/fC pancreatic tumors (40x magnification); (k) Adenocarcinoma, liver invasion (green arrows), (l) adenocarcinoma (yellow arrows), (m) PanINs (blue arrows). (n-o) quantification of PanIN and/or adenocarcinoma areas in WT-KPf/fC and Msi2−/−-KPf/fC tumors (n=6). (p) Survival of autochthonous Msi2−/−-KPf/fC (n=19) or WT-KPf/fC (n=32) mice. Log-rank (Mantel-Cox) survival analysis (p<0.0001). Data represented as mean ± SEM. ** P < 0.01, *** P < 0.001 by Student's t-test. Source Data for all panels are available online.
Mentions: Because Msi expression rose during progression (Extended Data Fig. 1f-k, 4a), and marked therapy resistant cells, we tested if genetic or pharmacologic targeting of Msi could eradicate this ‘high risk’ population. Deletion of Msi1 led to a 5-fold reduction in tumor volume by MRI (Fig. 2a-b, Extended Data Fig. 4b, Supplementary Videos S2-S4). Histologically, adenocarcinoma areas comprised 67% of WT-KPf/fC but less than 10% of Msi1−/−KPf/fC pancreata; further while Msi1 loss allowed low grade PanINs to form, it largely blocked progression to adenocarcinoma (Fig. 2c-f, Extended Data Fig. 4 c, d). Finally, Msi1 deletion improved survival in orthotopic grafts: median survival for WT-KPf/fC graft recipients was 28.5 days, and for Msi1−/−-KPf/fC grafts was 70.5 days, representing a 2.5-fold increase in survival time and a 23-fold decrease in risk of death (Fig. 2g).

View Article: PubMed Central - PubMed

ABSTRACT

Pancreatic intraepithelial neoplasia (PanIN) is a premalignant lesion that can progress to pancreatic ductal adenocarcinoma, a highly lethal malignancy marked by its late stage at clinical presentation and profound drug resistance1. The genomic alterations that commonly occur in pancreatic cancer include activation of KRAS2 and inactivation of p53, and SMAD42-4. To date, however, it has been challenging to target these pathways therapeutically; thus the search for other key mediators of pancreatic cancer growth remains an important endeavor. Here we show that the stem cell determinant Musashi (Msi) is a critical element of pancreatic cancer progression in both genetic models and patient derived xenografts. Specifically, we developed Msi reporter mice that allowed image based tracking of stem cell signals within cancers, revealing that Msi expression rises as PanIN progresses to adenocarcinoma, and that Msi-expressing cells are key drivers of pancreatic cancer: they preferentially harbor the capacity to propagate adenocarcinoma, are enriched in circulating tumor cells, and are markedly drug resistant. This population could be effectively targeted by deletion of either Msi1 or Msi2, which led to a striking defect in PanIN progression to adenocarcinoma and an improvement in overall survival. Msi inhibition also blocked the growth of primary patient-derived tumors, suggesting that this signal is required for human disease. To define the translational potential of this work we developed antisense oligonucleotides against Msi; these showed reliable tumor penetration, uptake and target inhibition, and effectively blocked pancreatic cancer growth. Collectively, these studies highlight Msi reporters as a unique tool to identify therapy resistance, and define Msi signaling as a central regulator of pancreatic cancer.

No MeSH data available.


Related in: MedlinePlus