Activation of Akt protects cancer cells from growth inhibition induced by PKM2 knockdown

Qin, Xiaodong; Du, Yiqing; Chen, Xing; Li, Wuyan; Zhang, Jinghong; Yang, Jinbo

doi:10.1186/2045-3701-4-20

Cited by 12 publications

(5 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…One study showed that knockdown of PKM2 leads to activation of Akt and inhibition of PI3K/Akt signaling pathway, resulting in significant growth inhibition and apoptosis in PKM2 knockdown cells, which indicated Akt activation was necessary for the survival of PKM2 knockdown cells. 78 In fact, activated Akt is a well-established survival factor and activated Akt modulates the function of many substrates involved in the regulation of cell survival, cell cycle progression and cellular growth. 79 Thus, our results offer additional evidence to support that PKM2 knockout cells may rely on regulation of the PI3K/Akt pathway to survive.…”

Section: Resultsmentioning

confidence: 99%

Site-specific characterization and quantitation ofN-glycopeptides in PKM2 knockout breast cancer cells using DiLeu isobaric tags enabled by electron-transfer/higher-energy collision dissociation (EThcD)

Chen

Hao

et al. 2018

Analyst

View full text Add to dashboard Cite

The system-wide site-specific analysis of intact glycopeptides is crucial for understanding the exact functional relevance of protein glycosylation. A dedicated workflow with the capability to simultaneously characterize and quantify intact glycopeptides in a site-specific and high-throughput manner is essential to reveal specific glycosylation alteration patterns in complex biological systems. In this study, an enhanced, dedicated, large-scale site-specific quantitative N-glycoproteomics workflow has been established, which includes improved specific extraction of membrane-bound glycoproteins using the filter aided sample preparation (FASP) method, enhanced enrichment of N-glycopeptides using sequential hydrophilic interaction liquid chromatography (HILIC) and multi-lectin affinity (MLA) enrichment, site-specific N-glycopeptide characterization enabled by EThcD, relative quantitation utilizing isobaric N,N-dimethyl leucine (DiLeu) tags and automated FDR-based large-scale data analysis by Byonic. For the first time, our study shows that HILIC complements to a very large extent to MLA enrichment with only 20% overlapping in enriching intact N-glycopeptides. When applying the developed workflow to site-specific N-glycoproteome study in PANC1 cells, we were able to identify 1067 intact N-glycopeptides, representing 311 glycosylation sites and 88 glycan compositions from 205 glycoproteins. We further applied this approach to study the glycosylation alterations in PKM2 knockout cells vs. parental breast cancer cells and revealed altered N-glycoprotein/N-glycopeptide patterns and very different glycosylation microheterogeneity for different types of glycans. To obtain a more comprehensive map of glycoprotein alterations, N-glycopeptides after treatment with PNGase F were also analyzed. A total of 484 deglycosylated peptides were quantified, among which 81 deglycosylated peptides from 70 glycoproteins showed significant changes. KEGG pathway analysis revealed that the PI3K/Akt signaling pathway was highly enriched, which provided evidence to support the previous finding that PKM2 knockdown cancer cells rely on activation of Akt for their survival. With glycosylation being one of the most important signaling modulators, our results provide additional evidence that signaling pathways are closely regulated by metabolism.

show abstract

Section: Resultsmentioning

confidence: 99%

Site-specific characterization and quantitation ofN-glycopeptides in PKM2 knockout breast cancer cells using DiLeu isobaric tags enabled by electron-transfer/higher-energy collision dissociation (EThcD)

Chen

Hao

et al. 2018

Analyst

View full text Add to dashboard Cite

show abstract

“…It is a regulated catabolic pathway to digest cellular organelles and macromolecules in order to generate energy 36 , 37 . Autophagy remains in a very high level in PC cells and plays an important role in carcinogenesis 38 , 39 . The present study demonstrated that hypoglucose induced remarkable autophagy in PC cells, which was further enhanced by PKM2 downregulation and repressed by PKM2 overexpression.…”

Section: Discussionmentioning

confidence: 99%

The responsively decreased PKM2 facilitates the survival of pancreatic cancer cells in hypoglucose

Deng

Liu

et al. 2018

Cell Death Dis

View full text Add to dashboard Cite

Cancer cells predominantly produce energy at a high rate of glycolysis even in aerobic environment. It is termed as Warburg effect and is necessary for the tumorigenesis. Studies showed pyruvate kinase M2 (PKM2), a key regulator of the Warburg effect, is overexpressed and involved in numerous cancers. However, the expression and function of PKM2 in pancreatic cancer (PC) remain undefined. Our results showed that PKM2 is overexpressed in the PC tissue compared to the peritumoral tissue. Unexpected, the downregulation of PKM2 did not affect the proliferation, invasion, and chemoresistance of PC cells. Since pancreatic cancer is a hypovascular tumor with comparably insufficient energy supply, we further investigate the relationship between PKM2 and hypoglucose. Interestingly, we further discovered that decreased expression of PKM2 was detected in PC samples with lower microvessel density as well as in PC cells treated with hypoglucose condition (0.5 mM). Furthermore, the downregulation of PKM2 facilitated, while the upregulation of PKM2 inhibited, PC cells survival during hypoglucose. We further revealed that the repressed PKM2 induced autophagy, high NADPH/NADP ratio, and biomacromolecule production, but reduced ROS accumulation. Moreover, AMPKα1 knockdown repressed the autophagy and survival of PC cells during hypoglucose, which were promoted by PKM2 knockdown. Collectively, our study indicates that decreased PKM2 diverts glucose metabolism to biomacromolecule accumulation and antioxidants generation during glucose deprivation. This metabolism alteration elevates AMPKα1-dependent autophagy, which facilitates PC cell survival during glucose deprivation. Therefore, functions of PKM2 are complicated and cannot be defined as oversimplified promoter or inhibitor in PC.

show abstract

“…This opinion is supported by a recent study conducted by Israelsen et al (27), in which PKM2 knock out reprogrammed tumors to express PKM1, which instead of regressing, stimulated tumor propagation. A recent study by Qin et al (32) states that Akt survival signaling that activated, followed by PKM2 knockdown, conferred protection against growth inhibition and apoptosis.…”

Section: Discussionmentioning

confidence: 99%

Pyruvate kinase M knockdown–induced signaling via AMP-activated protein kinase promotes mitochondrial biogenesis, autophagy, and cancer cell survival

Prakasam¹,

Singh

Iqbal

et al. 2017

Journal of Biological Chemistry

View full text Add to dashboard Cite

Preferential expression of the low-activity (dimeric) M2 isoform of pyruvate kinase (PK) over its constitutively active splice variant M1 isoform is considered critical for aerobic glycolysis in cancer cells. However, our results reported here indicate co-expression of PKM1 and PKM2 and their possible physical interaction in cancer cells. We show that knockdown of either PKM1 or PKM2 differentially affects net PK activity, viability, and cellular ATP levels of the lung carcinoma cell lines H1299 and A549. The stable knockdown of PK isoforms in A549 cells significantly reduced the cellular ATP level, whereas in H1299 cells the level of ATP was unaltered. Interestingly, the PKM1/2 knockdown in H1299 cells activated AMP-activated protein kinase (AMPK) signaling and stimulated mitochondrial biogenesis and autophagy to maintain energy homeostasis. In contrast, knocking down either of the PKM isoforms in A549 cells lacking LKB1, a serine/threonine protein kinase upstream of AMPK, failed to activate AMPK and sustain energy homeostasis and resulted in apoptosis. Moreover, in a similar genetic background of silenced PKM1 or PKM2, the knocking down of AMPKα1/2 catalytic subunit in H1299 cells induced apoptosis. Our findings help explain why previous targeting of PKM2 in cancer cells to control tumor growth has not met with the expected success. We suggest that this lack of success is because of AMPK-mediated energy metabolism rewiring, protecting cancer cell viability. On the basis of our observations, we propose an alternative therapeutic strategy of silencing either of the PKM isoforms along with AMPK in tumors.

show abstract

Activation of Akt protects cancer cells from growth inhibition induced by PKM2 knockdown

Cited by 12 publications

References 9 publications

Site-specific characterization and quantitation ofN-glycopeptides in PKM2 knockout breast cancer cells using DiLeu isobaric tags enabled by electron-transfer/higher-energy collision dissociation (EThcD)

Site-specific characterization and quantitation ofN-glycopeptides in PKM2 knockout breast cancer cells using DiLeu isobaric tags enabled by electron-transfer/higher-energy collision dissociation (EThcD)

The responsively decreased PKM2 facilitates the survival of pancreatic cancer cells in hypoglucose

Pyruvate kinase M knockdown–induced signaling via AMP-activated protein kinase promotes mitochondrial biogenesis, autophagy, and cancer cell survival

Contact Info

Product

Resources

About