-
Categories
-
Pharmaceutical Intermediates
-
Active Pharmaceutical Ingredients
-
Food Additives
- Industrial Coatings
- Agrochemicals
- Dyes and Pigments
- Surfactant
- Flavors and Fragrances
- Chemical Reagents
- Catalyst and Auxiliary
- Natural Products
- Inorganic Chemistry
-
Organic Chemistry
-
Biochemical Engineering
- Analytical Chemistry
-
Cosmetic Ingredient
- Water Treatment Chemical
-
Pharmaceutical Intermediates
Promotion
ECHEMI Mall
Wholesale
Weekly Price
Exhibition
News
-
Trade Service
Introduction Small cell lung cancer (SCLC) accounts for 13%-15% of lung cancers
.
SCLC is very aggressive (its doubling time is fast and it is easy to spread early), resulting in 80%-85% of patients being diagnosed with generalized disease, and the 5-year overall survival rate (OS) is only 5%-6%
.
SCLC is highly sensitive to chemotherapy and radiotherapy at first, but treatment resistance generally appears in the later stage, especially the lack of effective follow-up treatment after recurrence, which leads to poor prognosis of patients
.
Clinically, there is an urgent need to clarify the mechanism of SCLC treatment resistance
.
Recently, the research team of Professor Ming Chen from the Center for Cancer Prevention and Treatment of Sun Yat-sen University explored the mechanism of resistance to SCLC treatment by comparing the genotypes and phenotypes of treatment-sensitive and drug-resistant SCLC tumor samples.
The results of the study were published in Clinical cancer research (IF =12.
531)
.
Research background In the past thirty years, platinum-based dual-drug chemotherapy has been the main treatment for SCLC
.
Concurrent chemoradiotherapy (CCRT) is still the standard of treatment for limited-period (LS)-SCLC
.
Recently, immune checkpoint inhibitors targeting programmed death receptor-ligand 1 (PD-L1) have become the first-line standard treatment for patients with extensive stage (ES)-SCLC in combination with chemotherapy
.
SCLC is highly sensitive to chemotherapy and radiotherapy at first, but treatment resistance generally appears in the later stage, especially the lack of effective follow-up treatment after recurrence, which leads to poor prognosis of patients
.
Although radiotherapy for limited-stage disease and the increase in immunotherapy for extensive-stage disease, recurrence is usually inevitable
.
Therefore, it is urgent to clarify the mechanism of SCLC treatment resistance
.
Recently, a study using whole exome sequencing (WES) showed that WNT signal activation may be the mechanism of SCLC treatment failure, but so far there has been no similar study for Asian patients
.
Professor Chen Ming's research team from the Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital) explored the mechanism of SCLC treatment resistance by comparing the genotypes and phenotypes of treatment-sensitive and drug-resistant SCLC tumor samples
.
WES was performed on 11 newly diagnosed and recurring tumor samples of LS-SCLC who received CCRT treatment
.
Targeted sequencing of 1,021 cancer-related genes was performed on cell-free DNA (cfDNA) obtained at normal levels and at recurrence in 9 LS-SCLC patients who received CCRT treatment
.
In addition, proteomics based on label-free mass spectrometry was performed on formalin-fixed paraffin-embedded (FFPE) tumor samples from 28 chemotherapy-resistant and 23 chemotherapy-sensitive ES-SCLC patients
.
Finally, they further validated their findings by analyzing the transcriptome data of SCLC cell lines with different treatment sensitivities from public databases and conducting in vitro studies on chemotherapy-resistant and chemotherapy-sensitive SCLC cell lines
.
Enrichment of genome changes after radiotherapy and chemotherapy In the PI3K/AKT pathway, the genome profiles of newly treated and recurring SCLC tumors are first compared to determine the genomes related to recurrence after CCRT
.
Among the 2827 mutations in all patients, the baseline and recurrence samples shared 1997 mutations (Figure 1A)
.
Figure 1B shows treatment-naive specific mutations shared by each patient (present at the initial diagnosis but not at the time of relapse) and recurrence-specific mutations (present at the time of relapse but not at the time of initial diagnosis) Percentage
.
We observed a total of 71% (ranging from 39%-94%) mutations between newly treated and recurrent SCLC tumors, similar to non-small cell lung cancer (NSCLC), but significantly higher than breast cancer and colorectal cancer
.
An average of 94% of newly treated tumor mutations were also found in recurrent tumors
.
Figure 1.
Mutation frequency.
A total of 630 recurrence-specific (or acquired) mutations were identified in 684 genes in 11 patients (Figure 1A).
The median number of acquired mutations in recurrence samples was 74 (ranging from 1 -32)
.
The highest recurrence-specific mutation genes are RB1, PCLO, DNAH5, PRUNE2, SYNE1 and TACC2
.
Among these genes, PCLO is reported to be associated with etoposide resistance in ES-SCLC, while TACC2 has been shown to be associated with treatment resistance in neuroblastoma, renal cell carcinoma, and prostate cancer
.
These acquired mutations involve multiple pathways, especially the PI3K/AKT pathway
.
The genes with acquired mutations are enriched in the PI3K/AKT signaling pathway.
There are a total of 20 genes in 11 patients, of which 16 genes are located upstream of the pathway
.
The clonal evolution of SCLC under radiotherapy and chemotherapy.
Next, PyClone is used to infer the subclonal structure of newly treated and recurrent SCLC tumors to describe the clonal evolution under radiotherapy and chemotherapy
.
Most shared mutations (95%) showed an increase in CCF (referring to the proportion of cells containing a certain SNV in tumor cells) of recurrent tumors, including an increase in 714 CCFs
.
In addition, the number of clones in circulating samples was also significantly higher than that in untreated samples, indicating that new clones appeared after CCRT
.
Then, we compared the subclonal structure between the newly-treated tumor and the recurrent tumor matched by each patient
.
The cluster with the largest average CCF mutation is defined as the primary clone, otherwise it is defined as the secondary clone or subclone
.
In general, the major clones in newly treated tumors appear as major or minor clones in recurrent tumors (Figure 2)
.
Figure 2.
Acquired changes and KEGG pathway enrichment analysis.
Based on the changes in clonal structure in newly treated and recurrent tumors, we have identified two evolutionary models
.
The first model shows the presence of persistent major clones in both the newly treated and recurrent tumors (patients N04, N05, N06, N07, N09, and N10)
.
The second model is characterized by the weakening of the main clones in the newly treated tumors, and then continues to evolve into two evolutionary models
.
Specifically, patients N01, N03, and N11 showed that some minor clones in untreated tumors expanded into major clones in recurrent tumors (Figure 3)
.
On the other hand, patients N02 and N08 showed the emergence and rapid expansion of new clones as the main clones in recurrent tumors
.
Figure 3.
The paired cancer cell scores of the paired samples of each patient before treatment are verified in the independent SCLC patient cohort and public data set to verify the activation of the PI3K/AKT pathway due to the special activation of the PI3K/AKT pathway related to recurrence after SCLC treatment Interested, the researchers tried to verify these findings in other patient samples and publicly available SCLC data sets
.
First, 1,021 cancer-related genes were targeted for sequencing of cfDNA at the initial diagnosis, and an independent cohort of 9 LS-SCLC patients receiving CCRT treatment was studied
.
Next, a second independent set of 28 chemotherapy-resistant and 23 chemotherapy-sensitive ES-SCLC samples was obtained from patients receiving standard platinum-based chemotherapy
.
Proteomics based on label-free MS has been applied to identify the differentially expressed proteins between chemotherapy-resistant and chemotherapy-sensitive SCLC
.
MS analysis revealed 85 differentially expressed proteins, including 36 up-regulated genes and 49 down-regulated genes in chemotherapy-resistant small cell lung cancer
.
Many of these genes are related to aggressive cancer biology and treatment resistance of various cancers
.
In addition, KEGG pathway enrichment analysis showed that genes that differentially upregulated proteins were enriched in WNT signaling pathway, RNA degradation, purine metabolism, and HIF-1 signaling pathway
.
The PI3K/AKT pathway plays a key role in maintaining the transcription, translation and biological activity of HIF-1α in various malignant tumors
.
Seven of them: KT1, AKT3, BCL2, IL6R, PIK3CA, PIK3CB and RPS6 participate in the HIF-1 pathway, and six of them are located upstream of HIF-1
.
Figure 4.
Validation of PI3K/AKT pathway activation in other SCLC patients.
In vitro validation of PI3K/AKT pathway activation function related to treatment resistance of small cell lung cancer.
Researchers further tried to use a pair of chemotherapy sensitivity (H69) and chemotherapy resistance (H69AR) ) SCLC cell line to verify the role of PI3K/AKT pathway in the development of resistance to SCLC therapy
.
The H69 cell line contains mutations in several PI3K/AKT pathway genes, and H69AR shows cisplatin resistance compared with H69 cells
.
They evaluated the expression of 14 genes that carry acquired CNV, with a copy number ratio (relapsed/newly treated tumor) >1.
5 copy number increase or <0.
5 copy number loss
.
Consistent with CNV analysis, MYB, PI3KCA, HSP90AA1, and BCL2 with increased copy number were up-regulated, while TP53 with copy number loss was down-regulated in H69AR cells
.
In addition, Western blotting was performed to evaluate the total protein and the phosphorylated form of key genes in the PI3K/AKT pathway
.
Phosphorylation of AKT and its downstream targets 4EBP-1 and p70S6 was increased in chemotherapy-resistant H69AR cells
.
Finally, H69AR, DMS53 and H446 cells treated with or without PI3K inhibitors (including BEZ235, BKM120 and GSK2126458) were treated with cisplatin for cell viability determination
.
Figure 5.
Validation study results of PI3K/AKT pathway activation in vitro.
Genomic analysis showed that when LS-SCLC relapses, genes in the PI3K/AKT signaling pathway are enriched by acquired somatic mutations or high-frequency acquired CNV
.
Pathway analysis of differentially upregulated proteins from the ES-SCLC cohort revealed the enrichment of the HIF-1 signaling pathway
.
Most importantly, 7 of the 62 PI3K/AKT pathway genes with acquired somatic copy number amplification are rich in HIF-1 pathway
.
Finally, the analysis of the transcriptome data of SCLC cell lines from public databases confirmed the upregulation of PI3K/AKT and HIF-1 pathways in chemotherapy-resistant SCLC cell lines
.
References: Jin, Y.
, Chen, Y.
, Tang, H.
, Hubert, SM, Li, Q.
, Hu, X.
, Su, D.
, Xu, H.
, Fan, Y.
, Yu, X .
, Chen, Q.
, Liu, J.
, Hong, W.
, Xu, Y.
, Deng, H.
, Zhu, D.
, Li, P.
, Gong, Y.
, Xia, X.
, Gay, CM ,… Chen, M.
(2021).
Activation of PI3K/AKT pathway is a potential mechanism of treatment resistance in small cell lung cancer.
Clinical cancer research: an official journal of the American Association for Cancer Research, clincanres.
1943.
2021.
Advance online publication.
https://doi.
org/10.
1158/1078-0432.
CCR-21-1943
.
SCLC is very aggressive (its doubling time is fast and it is easy to spread early), resulting in 80%-85% of patients being diagnosed with generalized disease, and the 5-year overall survival rate (OS) is only 5%-6%
.
SCLC is highly sensitive to chemotherapy and radiotherapy at first, but treatment resistance generally appears in the later stage, especially the lack of effective follow-up treatment after recurrence, which leads to poor prognosis of patients
.
Clinically, there is an urgent need to clarify the mechanism of SCLC treatment resistance
.
Recently, the research team of Professor Ming Chen from the Center for Cancer Prevention and Treatment of Sun Yat-sen University explored the mechanism of resistance to SCLC treatment by comparing the genotypes and phenotypes of treatment-sensitive and drug-resistant SCLC tumor samples.
The results of the study were published in Clinical cancer research (IF =12.
531)
.
Research background In the past thirty years, platinum-based dual-drug chemotherapy has been the main treatment for SCLC
.
Concurrent chemoradiotherapy (CCRT) is still the standard of treatment for limited-period (LS)-SCLC
.
Recently, immune checkpoint inhibitors targeting programmed death receptor-ligand 1 (PD-L1) have become the first-line standard treatment for patients with extensive stage (ES)-SCLC in combination with chemotherapy
.
SCLC is highly sensitive to chemotherapy and radiotherapy at first, but treatment resistance generally appears in the later stage, especially the lack of effective follow-up treatment after recurrence, which leads to poor prognosis of patients
.
Although radiotherapy for limited-stage disease and the increase in immunotherapy for extensive-stage disease, recurrence is usually inevitable
.
Therefore, it is urgent to clarify the mechanism of SCLC treatment resistance
.
Recently, a study using whole exome sequencing (WES) showed that WNT signal activation may be the mechanism of SCLC treatment failure, but so far there has been no similar study for Asian patients
.
Professor Chen Ming's research team from the Cancer Hospital of the University of Chinese Academy of Sciences (Zhejiang Cancer Hospital) explored the mechanism of SCLC treatment resistance by comparing the genotypes and phenotypes of treatment-sensitive and drug-resistant SCLC tumor samples
.
WES was performed on 11 newly diagnosed and recurring tumor samples of LS-SCLC who received CCRT treatment
.
Targeted sequencing of 1,021 cancer-related genes was performed on cell-free DNA (cfDNA) obtained at normal levels and at recurrence in 9 LS-SCLC patients who received CCRT treatment
.
In addition, proteomics based on label-free mass spectrometry was performed on formalin-fixed paraffin-embedded (FFPE) tumor samples from 28 chemotherapy-resistant and 23 chemotherapy-sensitive ES-SCLC patients
.
Finally, they further validated their findings by analyzing the transcriptome data of SCLC cell lines with different treatment sensitivities from public databases and conducting in vitro studies on chemotherapy-resistant and chemotherapy-sensitive SCLC cell lines
.
Enrichment of genome changes after radiotherapy and chemotherapy In the PI3K/AKT pathway, the genome profiles of newly treated and recurring SCLC tumors are first compared to determine the genomes related to recurrence after CCRT
.
Among the 2827 mutations in all patients, the baseline and recurrence samples shared 1997 mutations (Figure 1A)
.
Figure 1B shows treatment-naive specific mutations shared by each patient (present at the initial diagnosis but not at the time of relapse) and recurrence-specific mutations (present at the time of relapse but not at the time of initial diagnosis) Percentage
.
We observed a total of 71% (ranging from 39%-94%) mutations between newly treated and recurrent SCLC tumors, similar to non-small cell lung cancer (NSCLC), but significantly higher than breast cancer and colorectal cancer
.
An average of 94% of newly treated tumor mutations were also found in recurrent tumors
.
Figure 1.
Mutation frequency.
A total of 630 recurrence-specific (or acquired) mutations were identified in 684 genes in 11 patients (Figure 1A).
The median number of acquired mutations in recurrence samples was 74 (ranging from 1 -32)
.
The highest recurrence-specific mutation genes are RB1, PCLO, DNAH5, PRUNE2, SYNE1 and TACC2
.
Among these genes, PCLO is reported to be associated with etoposide resistance in ES-SCLC, while TACC2 has been shown to be associated with treatment resistance in neuroblastoma, renal cell carcinoma, and prostate cancer
.
These acquired mutations involve multiple pathways, especially the PI3K/AKT pathway
.
The genes with acquired mutations are enriched in the PI3K/AKT signaling pathway.
There are a total of 20 genes in 11 patients, of which 16 genes are located upstream of the pathway
.
The clonal evolution of SCLC under radiotherapy and chemotherapy.
Next, PyClone is used to infer the subclonal structure of newly treated and recurrent SCLC tumors to describe the clonal evolution under radiotherapy and chemotherapy
.
Most shared mutations (95%) showed an increase in CCF (referring to the proportion of cells containing a certain SNV in tumor cells) of recurrent tumors, including an increase in 714 CCFs
.
In addition, the number of clones in circulating samples was also significantly higher than that in untreated samples, indicating that new clones appeared after CCRT
.
Then, we compared the subclonal structure between the newly-treated tumor and the recurrent tumor matched by each patient
.
The cluster with the largest average CCF mutation is defined as the primary clone, otherwise it is defined as the secondary clone or subclone
.
In general, the major clones in newly treated tumors appear as major or minor clones in recurrent tumors (Figure 2)
.
Figure 2.
Acquired changes and KEGG pathway enrichment analysis.
Based on the changes in clonal structure in newly treated and recurrent tumors, we have identified two evolutionary models
.
The first model shows the presence of persistent major clones in both the newly treated and recurrent tumors (patients N04, N05, N06, N07, N09, and N10)
.
The second model is characterized by the weakening of the main clones in the newly treated tumors, and then continues to evolve into two evolutionary models
.
Specifically, patients N01, N03, and N11 showed that some minor clones in untreated tumors expanded into major clones in recurrent tumors (Figure 3)
.
On the other hand, patients N02 and N08 showed the emergence and rapid expansion of new clones as the main clones in recurrent tumors
.
Figure 3.
The paired cancer cell scores of the paired samples of each patient before treatment are verified in the independent SCLC patient cohort and public data set to verify the activation of the PI3K/AKT pathway due to the special activation of the PI3K/AKT pathway related to recurrence after SCLC treatment Interested, the researchers tried to verify these findings in other patient samples and publicly available SCLC data sets
.
First, 1,021 cancer-related genes were targeted for sequencing of cfDNA at the initial diagnosis, and an independent cohort of 9 LS-SCLC patients receiving CCRT treatment was studied
.
Next, a second independent set of 28 chemotherapy-resistant and 23 chemotherapy-sensitive ES-SCLC samples was obtained from patients receiving standard platinum-based chemotherapy
.
Proteomics based on label-free MS has been applied to identify the differentially expressed proteins between chemotherapy-resistant and chemotherapy-sensitive SCLC
.
MS analysis revealed 85 differentially expressed proteins, including 36 up-regulated genes and 49 down-regulated genes in chemotherapy-resistant small cell lung cancer
.
Many of these genes are related to aggressive cancer biology and treatment resistance of various cancers
.
In addition, KEGG pathway enrichment analysis showed that genes that differentially upregulated proteins were enriched in WNT signaling pathway, RNA degradation, purine metabolism, and HIF-1 signaling pathway
.
The PI3K/AKT pathway plays a key role in maintaining the transcription, translation and biological activity of HIF-1α in various malignant tumors
.
Seven of them: KT1, AKT3, BCL2, IL6R, PIK3CA, PIK3CB and RPS6 participate in the HIF-1 pathway, and six of them are located upstream of HIF-1
.
Figure 4.
Validation of PI3K/AKT pathway activation in other SCLC patients.
In vitro validation of PI3K/AKT pathway activation function related to treatment resistance of small cell lung cancer.
Researchers further tried to use a pair of chemotherapy sensitivity (H69) and chemotherapy resistance (H69AR) ) SCLC cell line to verify the role of PI3K/AKT pathway in the development of resistance to SCLC therapy
.
The H69 cell line contains mutations in several PI3K/AKT pathway genes, and H69AR shows cisplatin resistance compared with H69 cells
.
They evaluated the expression of 14 genes that carry acquired CNV, with a copy number ratio (relapsed/newly treated tumor) >1.
5 copy number increase or <0.
5 copy number loss
.
Consistent with CNV analysis, MYB, PI3KCA, HSP90AA1, and BCL2 with increased copy number were up-regulated, while TP53 with copy number loss was down-regulated in H69AR cells
.
In addition, Western blotting was performed to evaluate the total protein and the phosphorylated form of key genes in the PI3K/AKT pathway
.
Phosphorylation of AKT and its downstream targets 4EBP-1 and p70S6 was increased in chemotherapy-resistant H69AR cells
.
Finally, H69AR, DMS53 and H446 cells treated with or without PI3K inhibitors (including BEZ235, BKM120 and GSK2126458) were treated with cisplatin for cell viability determination
.
Figure 5.
Validation study results of PI3K/AKT pathway activation in vitro.
Genomic analysis showed that when LS-SCLC relapses, genes in the PI3K/AKT signaling pathway are enriched by acquired somatic mutations or high-frequency acquired CNV
.
Pathway analysis of differentially upregulated proteins from the ES-SCLC cohort revealed the enrichment of the HIF-1 signaling pathway
.
Most importantly, 7 of the 62 PI3K/AKT pathway genes with acquired somatic copy number amplification are rich in HIF-1 pathway
.
Finally, the analysis of the transcriptome data of SCLC cell lines from public databases confirmed the upregulation of PI3K/AKT and HIF-1 pathways in chemotherapy-resistant SCLC cell lines
.
References: Jin, Y.
, Chen, Y.
, Tang, H.
, Hubert, SM, Li, Q.
, Hu, X.
, Su, D.
, Xu, H.
, Fan, Y.
, Yu, X .
, Chen, Q.
, Liu, J.
, Hong, W.
, Xu, Y.
, Deng, H.
, Zhu, D.
, Li, P.
, Gong, Y.
, Xia, X.
, Gay, CM ,… Chen, M.
(2021).
Activation of PI3K/AKT pathway is a potential mechanism of treatment resistance in small cell lung cancer.
Clinical cancer research: an official journal of the American Association for Cancer Research, clincanres.
1943.
2021.
Advance online publication.
https://doi.
org/10.
1158/1078-0432.
CCR-21-1943
